&EPA
United States
Environmental Protection
Agency
Office of
Research and Development
Washington, DC 20460
EPA/600/4-79/020
March 1983
Methods for
Chemical Analysis of
Water and Wastes
-------
MANUAL DISTRIBUTION RECORD
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future revisions of existing methods and the addition of new methods may be distributed to Manual
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any revisions and new additions to this Manual as they become available
-------
U S. Environmental Protection Agency
Environmental Monitoring and Support Laboratory
26 W St. Clair Street
Cincinnati, OH 45268
ATTN: Distribution Record System
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EPA-600/4-79-020
METHODS FOR CHEMICAL ANALYSIS
OF WATER AND WASTES
March 1983
Second Printing June 1982
ENVIRONMENTAL MONITORING AND SUPPORT
LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U S ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
Printed on Recycled Paper _
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DISCLAIMER
The mention of trade names or commercial products in this manual is for illustration purposes, and
does not constitute endorsement or recommendation for use by the U S Environmental Protection
Agency
n
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FOREWORD
The accomplishment of our objective m protecting the environment requires a reliable assessment of
the present condition and a determination of the effectiveness of corrective measures Decisions
which must be made on the need for pollution abatement and the most efficient means of achieving
environmental quality depend upon the availability of sound data Test procedures for measurement
of the presence and concentration of substances hazardous to human health as well as an evaluation
of the quality of the environment are essential to satisfactory decision-making
This manual of chemical methods was prepared by the staff of the Environmental Monitoring and
Support Laboratory of the Environmental Research Laboratory, Cincinnati to provide procedures
for monitoring water supplies, waste discharges, and the quality of ambient waters These test
methods have been carefully selected to meet the needs of Federal Legislation and to provide
guidance to laboratories engaged in protecting human health and the aquatic environment The
contributions and counsel of scientists in other EPA laboratories are gratefully acknowledged
Test procedures contained herein, that are approved for water and waste monitoring under the Safe
Drinking Water Act (SDWA) and the National Pollutant Discharge Elimination System (NPDES),
of PL 92-500 are so indicated at the bottom of each title page These approved methods are also
recommended for ambient monitoring needs of Section 106 and 208 of PL 92-500 Methods without
this stated approval are presented for information only Correspondence on these methods is invited
)<£r£z*v4^
Robert L Booth
Acting Director, Environmental Monitoring and
Support Laboratory, Cincinnati, Ohio 45268
111
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ABSTRACT
This manual provides test procedures approved for the monitoring of water supplies, waste
discharges, and ambient waters, under the Safe Drinking Water Act, the National Pollutant
Discharge Elimination System, and Ambient Monitoring Requirements of Section 106 and 208
of Public Law 92-500 The test methods have been selected to meet the needs of federal legislation
and to provide guidance to laboratories engaged in the protection of human health and the
aquatic environment
IV
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CONTENTS
Foreword
Abstract
Introduction
Sample Preservation
EPA Quality Assurance Coordinators
100 Physical Properties
Color
Colonmetnc, ADMI
Colonmetnc, Platinum-Cobalt
Spectrophotometnc
Conductance
Specific Conductance
Hardness, Total (mg/1 as CaCO3)
Colonmetnc, Automated EDTA
Titnmetnc, EDTA
Odor
pH
Threshold Odor (Consistent Series)
Electrometnc
Electrometric (Continuous Monitoring)
Residue
Filterable
Gravimetric, Dried at 180°C
Non-Filterable
Gravimetric, Dried at 103-105°C
Total
Gravimetric, Dried at 103-105°C
Volatile
Gravimetric, Ignition at 550°C
Settleable Matter
Volumetric, Imhoff Cone
111
IV
*,
xni
XV
XX
Method 110 1
Method 1102
Method 1103
Method 120 1
Method 130 1
Method 1302
Method 140 1
Method 150 1
Method 150 2
Method 1601
Method 1602
Method 1603
Method 1604
Method 1605
-------
Temperature
Thermometnc
Turbidity
Nephelometnc
Atomic Absorption Methods
200 Metals
Inductively Coupled Plasma
Aluminum
AA, Direct Aspiration
AA, Furnace
Antimony
AA, Direct Aspiration
AA, Furnace
Arsenic
AA, Furnace
AA, Hydride
Spectrophotometnc, SDDC
Digestion Method for Hydride and SDDC
Barium
AA, Direct Aspiration
AA, Furnace
Beryllium
AA, Direct Aspiration
AA, Furnace
Boron
Colonmetnc, Curcumm
Cadmium
AA, Direct Aspiration
AA, Furnace .
Calcium
AA, Direct Aspiration
Titnmetnc, EDTA
Method 170 1
Method 1801
Section 2000
Method 200 7
Method 202 1
Method 202 2
Method 204 1
Method 2042
Method 206 2
Method 206 3
Method 2064
Method 206 5
Method 208 1
Method 208 2
Method 210 1
Method 2102
Method 212 3
Method 213 1
Method 213 2
Method 215 1
Method 215 2
VI
-------
Chromium
AA, Direct Aspiration
AA, Furnace
Chelation-Extraction
Hexavalent, Chelation-Extraction
Hexavalent, Dissolved
Cobalt
AA, Direct Aspiration
AA, Furnace
Copper
AA, Direct Aspiration
AA, Furnace
Gold
AA, Direct Aspiration
AA, Furnace
Indium
AA, Direct Aspiration
AA, Furnace
Iron
Lead
AA, Direct Aspiration
AA, Furnace
AA, Direct Aspiration
AA, Furnace
Magnesium
AA, Direct Aspiration
Manganese
AA, Direct Aspiration
AA, Furnace
Mercury
Cold Vapor, Manual
Cold Vapor, Automated
Cold Vapor, Sediments
Method 218 1
Method 218 2
Method 218 3
Method 2184
Method 2185
Method 219 1
Method 2192
Method 220 1
Method 2202
Method 231 1
Method 231 2
Method 235 1
Method 235 2
Method 236 1
Method 236 2
Method 239 1
Method 239 2
Method 242 1
Method 243 1
Method 243 2
Method 245 1
Method 245 2
Method 245 5
Vll
-------
Molybdenum
AA, Direct Aspiration
AA, Furnace
Nickel
AA, Direct Aspiration
AA, Furnace
Osmium
AA, Direct Aspiration
AA, Furnace
Palladium
AA, Direct Aspiration
AA, Furnace
Platinum
AA, Direct Aspiration
AA, Furnace
Potassium
AA, Direct Aspiration
Rhenium
AA, Direct Aspiration
AA, Furnace
Rhodium
AA, Direct Aspiration
AA, Furnace
Ruthenium
AA, Direct Aspiration
AA, Furnace
Selenium
AA, Furnace
AA, Hydride
Silver
AA, Direct Aspiration
AA, Furnace
Method 246 1
Method 246 2
Method 249 1
Method 249 2
Method 252 1
Method 252 2
Method 253 1
Method 253 2
Method 255 1
Method 255 2
Method 258 1
Method 264 1
Method 264 2
Method 265 1
Method 265 2
. Method 267 1
Method 267 2
Method 270 2
Method 2703
Method 272 1
Method 272 2
Vlll
-------
Sodium
AA, Direct Aspiration
AA, Furnace
Thallium
AA, Direct Aspiration
AA, Furnace
Tin
AA, Direct Aspiration
AA, Furnace
Titanium
AA, Direct Aspiration
AA, Furnace
Vanadium
AA, Direct Aspiration
AA, Furnace
Zinc
AA, Direct Aspiration
AA, Furnace
300 Inorganic, Non-metalhcs
Acidity
Titnmetnc
Titnmetric (acid rain) ...
Alkalinity
Titnmetnc (pH 4 5)
Colonmetnc, Automated Methyl Orange
Bromide
Titnmetnc
Chlonde
Colonmetnc, Automated Ferncyamde, AA I
Colonmetnc, Automated Ferncyamde, AA II
Titnmetnc, Mercunc Nitrate
Chlonne, Total Residual
Titnmetnc, Amperometnc
Titnmetnc, Back-Iodometnc
Method 273 1
Method 273 2
Method 279 1
Method 279 2
Method 282 1
Method 2822
Method 283 1
Method 283 2
Method 286 1
Method 286 2
Method 289 1
Method 289 2
Method 305 1
Method 305 1
Method 310 1
Method 3102
Method 320 1
Method 325 1
Method 3252
Method 325 3
Method 330 1
Method 3302
IX
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Titrimetric, lodometric [[[ Method 330.3
Titrimetric, DPD-FAS .................................................. . ................... .. Method 330.4
Spectrophotometric, DPD [[[ Method 330.5
; i ,.-,'• #
Cyanide -;
Amenable to Chlorination
Titrimetric, Spectrophotometric ................................................ Method 335.1
Total
Titrimetric, Spectrophotometric ................................................ Method 335.2
Colorimetric, Automated UV...., ..... . ........ ....... ................. ........ Method 335.3
Fluoride
Colorimetric, SPADNS with Bellack
Distillation [[[ ....... ..... . ..... Method 340.1
Potentiometric, Ion Selective Electrode ............................................. Method 340.2
Colorimetric, Automated Complexone .................. ..... . ....................... Method 340.3
Iodide
Titrimetric [[[ .Method 345.1
Nitrogen t;f
Ammonia
Colorimetric, Automated Phenate ............................... . ............ Method 350.1
Colorimetric; Titrimetric; Potentiometric -
Distillation Procedure [[[ Method 350.2
Potentiometric, Ion Selective Electrode ................................... Method 350.3
Kjeldahl, Total
Colorimetric, Automated Phenate
Colorimetric, Semi-Automated
Block Digester AAII
Colorimetric; Titrimetric; Potentiometric
Potentiometric, Ion Selective Electrode
Nitrate
Colorimetric, Brucine.
Nitrate-Nitrite
Colorimetric, Automated Hydrazine
Reduction ,
Colorimetric, Automated Cadmium Reduction
Colorimetric, Manual Cadmium Reduction ......
Method 351.1
Method 351.2
Method 351.3
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Nitrite
Spectrophotometnc
Oxygen, Dissolved
Membrane Electrode
Modified Wmkler (Full Bottle Technique)
Phosphorus
All Forms
Colonmetric, Automated, Ascorbic Acid
Colonmetnc, Ascorbic Acid,
Single Reagent
Colonmetnc, Ascorbic Acid,
Two Reagent
Total
Colonmetnc, Automated, Block Digester, AA II
Silica, Dissolved
Colonmetnc
Sulfate
Colonmetnc, Automated Chloramlate
Colonmetnc, Automated Methyl Thymol Blue, AA II
Gravimetnc
Turbidimetric
Sulfide
Titnmetric, Iodine
Colonmetnc, Methylene Blue
Sulfite
Titnmetric
400 Orgamcs
Biochemical Oxygen Demand
BOD (5 day, 20°C)
Chemical Oxygen Demand
Titnmetric, Mid-Level
Titrimetric, Low Level
Titnmetric, High Level for Saline Waters
Colonmetnc, Automated, Manual
Method 354 1
Method 360 1
Method 3602
Method 365 1
Method 365 2
Method 365 3
Method 3654
Method 370 1
Method 375 1
Method 375 2
Method 375 3
Method 375.4
Method 376 1
Method 3762
Method 377 1
Method 405 1
Method 410.1
Method 4102
Method 410 3
Method 4104
XI
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Oil and Grease, Total Recoverable
Gravimetric, Separatory Funnel Extraction Method 413 1
Spectrophotometnc, Infrared Method 413 2
Organic Carbon, Total
Combustion or Oxidation Method 415 1
UV Promoted, Persulfate Oxidation. Method 4152
Petroleum Hydrocarbons, Total, Recoverable
Spectrophotometnc, Infrared . Method 418 1
Phenolics, Total Recoverable
Spectrophotometnc, Manual 4-AAP with Distillation . Method 420 1
Colonmetnc, Automated 4-AAP with Distillation Method 4202
Spectrophotometnc, MBTH with Distillation Method 420 3
Methylene Blue Active Substances (MBAS)
Colonmetnc . Method 425 1
NTA
Colonmetnc, Manual, Zmc-Zmcon . Method 4301
Colonmetnc, Automated, Zinc-Zmcon, Method 430 2
Xll
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INTRODUCTION
j
NO TL Since the first printing of this edition in March 1979, various editorial errors have been
brought to our attention which have been corrected in this second printing In
addition, it has been found necessary to add to this printing an updated preservation
and holding times table (Table 1), as well as six new methods They are undeTpH,
Llectrome tries (continuous monitoring), Method 1502, under Metals, Inductively
Coupled Plasma, 200 7, under Metals/Chromium Hexavalent, Dissolved, Method
218 5, under Metals/Sodium AA, Furnace, ^Method 2732, under Inorganic, non-
metalhcslAcidity Titnmetnc(acid ram), Method305 1, and under Organics, Organic
Carbon, Total UV Promoted, Persulfate, Oxidation, Method 415 2
These additions have been made so as to keep users of the manual current with the
procedures the Agency uses in determining compliance with applicable water and
effluent standards it has established
Persons who already possess a copy of the 1979 edition of the manual and who wish to
update it by including the cited additions need not request another copy The new
material is available as a separate volume, entitled, "Technical Additions to Methods
for Chemical Analysis of Water and Wastes, LPA-600/4-79-020," LPA-600/4-82-055,
from ORD Publications, CLRI, U S Environmental Protection Agency, Cincinnati,
OH 45268
This third edition of "Methods for Chemical Analysis of Water and Wastes" contains the chemical
analytical procedures used in U S Environmental Protection Agency (EPA) laboratories for the
examination of ground and surface waters, domestic and industrial waste effluents, and treatment
process samples Except where noted under "Scope and Application", the methods are-applicable to
both water and wastewaters, and both fresh and saline water samples The manual provides test
procedures for the measurement of physical, inorganic, and selected organic constituents and
pirameters Methods for pesticides, industrial organic waste materials, and sludges are given in other
publications of the Agency The methods were chosen through the combined efforts of the EPA
Regional Quality Assurance Coordinators, the staff of the Physical and Chemical Methods Branch,
Environmental Monitoring and Support Laboratory, and other senior chemists in both federal and
state laboratories Method selection was based on the following criteria
(1) The method should measure the desired property or constituent with precision,
accuracy, and specificity sufficient to meet the data needs of EPA, in the presence of the
interfering materials encountered in water and waste samples
(2) The procedure should utilize the equipment and skills available in modern water
pollution control laboratories
(3) The selected method is in use in many laboratories or has been sufficiently tested to
establish its validity
(4) The method should be rapid enough to permit routine use for the examination of a large
number of samples
Xlll
-------
Instrumental methods have been selected in preference to manual procedures because of the
improved speed, accuracy, and precision In keeping with this policy, procedures for the Techmcon
AutoAnalyzer have been included for laboratories having this equipment available Other
continuous flow automated systems using these identical procedures are acceptable
Intralaboratory and mterlaboratory precision and accuracy statements are provided where such data
are available These mterlaboratory statements are derived from mterlaboratory studies conducted
by the Quality Assurance Branch, Environmental Momtonng and Support Laboratory, the
American Society for Testing Materials, or the Analytical Reference Service of the US Public Health
Service, DHEW These methods may be used for measuring both total and dissolved constituents of
the sample When the dissolved concentration is to be determined, the sample is filtered through a
0 45-micron membrane filter and the filtrate analyzed by the procedure specified The sample should
be filtered as soon as possible after it is collected, preferably in the field Where field filtration is not
practical, the sample should be filtered as soon as it is received in the laboratory
Many water and waste samples are unstable In situations where the interval between sample
collection and analysis is long enough to produce changes in either the concentration or the physical
state of the constituent to be measured, the preservation practices in Table I are recommended
This manual is a basic reference for monitoring water and wastes in compliance with the
requirements of the Federal Water Pollution Control Act Amendments of 1972 Although other test
procedures may be used, as provided in the Federal Register issue of October 16, 1973 (38FR 28758)
and in subsequent amendments, the methods described in this manual will be used by the
Environmental Protection Agency in determining compliance with applicable water and effluent
standards established by the Agency
Although a sincere effort has been made to select methods that are applicable to the widest range of
sample types, significant interferences may be encountered in certain isolated samples In these
situations, the analyst will be providing a valuable service to EPA by defining the nature of the
interference with the method and bringing this information to the attention of the Director,
Environmental Momtonng and Support Laboratory, through the appropriate Quality Assurance
Coordinator
X1.V
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SAMPLE PRESERVATION
Complete and unequivocal preservation of samples, either domestic sewage, industrial wastes, or
natural waters, is a practical impossibility Regardless of the nature of the sample, complete stability
for every constituent can never be achieved At best, preservation techniques can only retard the
chemical and biological changes that inevitably continue after the sample is removed from the parent
source The changes that take place m a sample are either chemical or biological In the former case,
certain changes occur in the chemical structure of the constituents that are a function of physical
conditions Metal cations may precipitate as hydroxides or form complexes with other constituents,
cations or anions may change valence states under certain reducing or oxidizing conditions, other
constituents may dissolve or volatilize with the passage of time Metal cations may also adsorb onto
surfaces (glass, plastic, quartz, etc ), such as, iron and lead Biological changes taking place in a
sample may change the valence of an element or a radical to a different valence Soluble constituents
may be converted to organically bound materials in cell structures, or cell lysis may result in release
of cellular material into solution The well known nitrogen and phosphorus cycles are examples of
biological influence on sample composition Therefoie, as a general rule, it is best to analyze the
samples as soon as possible after collection This is especially true when the analyte concentration is
expected to be m the low ug/1 range
Methods of preservation are relatively limited and are intended generally to (1) retard biological
action, (2) retard hydrolysis of chemical compounds and complexes, (3) reduce volatility of
constituents, and (4) reduce absorption effects Preservation methods are generally limited to pH
control, chemical addition, refrigeration, and freezing
The recommended preservative for various constituents is given in Table 1 These choices are based
on the accompanying references and on information supplied by various Quality Assurance
Coordinators As more data become available, these recommended holding times will be adjusted to
reflect new information Other information provided in the table is an estimation of the volume of
sample required for the analysis, the suggested type of container, and the maximum recommended
holding times for samples properly preserved
xv
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TABLE 1
RECOMMENDATION FOR SAMPLING AND PRESERVATION
OF SAMPLES ACCORDING TO MEASUREMENT™
Measurement
100 Physical Properties
Color
Conductance
Hardness
Odor
pH
Residue
Filterable
Non-
Filterable
Total
Volatile
Settleable Matter
Temperature
Turbidity
200 Metals
Dissolved
Suspended
Total
Vol
Req
(ml)
50
100
100
200
25
100
100
100
100
1000
1000
100
200
200
100
Container2
P,G
P,G
P,G
G only
P,G
P,G
P,G
P,G
P,G
P,G
P,G
P,G
P,G
P,G
Preservative3''
Cool, 4°C
Cool, 4°C
HNO3 to pH<2
Cool, 4°C
None Req
Cool, 4°C
Cool, 4°C
Cool, 4°C
Cool, 4°C
Cool, 4°C
None Req
Cool, 4°C
Filter on site
HNO3 to pH<2
Filter on site
HNO3 to PH<2
Holding
Time5
4.8 Hrs
28 Days
6 Mos
24 Hrs
Analyze
Immediately
7 Days
7 Days
7 Days
7 Days
48 Hrs
Analyze
Immediately
48 Hrs
6 Mos
6 Mos
6 Mos
(8)
XVI
-------
TABLE 1 (CONT)
Vol
Req
Measurement (ml)
Chromium*6
Mercury
Dissolved
Total
300 Inorganics, Non-Metalhcs
Acidity
Alkalinity
Bromide
Chloride
Chlorine
Cyanides
Fluoride
Iodide
Nitrogen
Ammonia
Kjeldahl, Total
Nitrate plus Nitrite
Nitrate9
Nitrite
200
100
100
100
100
100
50
200
500
300
100
400
500
100
100
50
Container2 Preservative3'4
P,G
P,G
P,G
P,G
P,G
P,G
P,G
P,G
P,G
P,G
P,G
P,G
P,G
P,G
P,G
P,G
f f
Cool, 4°C
Filter
HNO3 to pH<2
HN03 to pH<2
Cool,4°C
Cool, 4°C
None Req
None Req
None Req
Cool, 4°C
NaOH to pH >12
0 6g ascorbic acid6
None Req
Cool, 4°C
Cool,4°C
H2SO4 to pH<2
Cool, 4°C
H2SO4 to pH<2
Cool, 4°C
H2SO4 to pH<2
Cool, 4°C
Cool, 4°C
Holding
Time5
i
24Hrs
28 Days
28 Days
14 Days
14 Days
28 Days
28 Days
Analyze
Immediately
14 Days7
28 Days
24 Hrs
28 Days
28 Days
28 Days
48 Hrs
48 Hrs
xvu
-------
TABLE 1 (CONT)
Measurement
Dissolved Oxygen
Probe
Wmkler
Phosphorus
Ortho-
phosphate,
Dissolved
Hydrolyzable
Total
Total,
Dissolved
Silica
Sulfate
Sulfide
Sulfite
400 Orgamcs
BOD
COD
Oil & Grease
Organic carbon
Phenohcs
Vol
Req
(ml)
300
300
50
50
50
50
50
50
500
50
1000
50
1000
25
500
n
Container
G bottle and top
G bottle and top
P,G
P,G
P,G
P,G
P only
P,G
P,G
P,G
P,G
P,G
G only
P,G
G only
Preservative3'4
None Req
Fix on site
and store
in dark
Filter on site
Cool, 4°C
Cool, 4°C
H2SO4 to pH<2
Cool, 4°C
H2SO4 to pH<2
Filter on site
Cool, 4°C
H2SO4 to pH<2
Cool, 4°C
Cool, 4°C
Cool, 4°C
add 2 ml zinc
acetate plus NaOH
topH>9
None Req
Cool, 4°C
Cool, 4°C
H2SO4 to pH<2
Cool, 4°C
H2SO4 to pH<2
Cool, 4°C
H2SO4 or HC1 to pH<2
Cool, 4°C
Holding
Time5
Analyze
Immediately
8 Hours
48 Hrs
28 Days
28 Days
24 Hrs
28 Days
28 Days
7 Days
Analyze
Immediately
48 Hrs
28 Days
28 Days
28 Days
28 Days
to pH <2
XVlll
-------
TABLE 1 (CONT)
Vol
Req Holding
Measurement (ml) Container2 Preservative3'4 Time5
MBAS 250 P,G Cool, 4°C 48 Hrs
NTA 50 P,G Cool, 4°C 24 Hrs
1 More specific instructions for preservation and sampling are found with each procedure as
detailed in this manual A general discussion on sampling water and industrial wastewater may
be found in ASTM, Part 31, p 72-82 (1976) Method D-3370
2 Plastic (P) or Glass (G) For metals, polyethylene with a polypropylene cap (no liner) is
preferred
3 Sample preservation should be performed immediately upon sample collection For
composite samples each aliquot should be preserved at the time of collection When use of
an automated sampler makes it impossible to preserve each aliquot, then samples may be
preserved by maintaining at 4°C until compositing and sample splitting is completed
4 When any sample is to be shipped by common carrier or sent through the United States
Mails, it must comply with the Department of Transportation Hazardous Materials
Regulations (49 CFR Part 172) The person offering such material for transportation is
responsible for ensuring such compliance For the preservation requirements of Table 1,
the Office of Hazardous Materials, Materials Transportation Bureau, Department of
Transportation has determined that the Hazardous Materials Regulations do not apply to
the following materials Hydrochloric acid (HC1) in water solutions at concentrations of
0 04% by weight or less (pH about 1 96 or greater), Nitric acid (HNO3) in water solutions at
concentrations of 0 15% by weight or less (pH about 1 62 or greater), Sulfunc acid (H2SO4)
in water solutions at concentrations of 0 35% by weight or less (pH about 1 15 or greater),
Sodium hydroxide (NaOH) in water solutions at concentrations of 0 080% by weight or
less (pH about 12 30 or less)
5 Samples should be analyzed as soon as possible after collection The times listed are the
maximum times that samples may be held before analysis and still considered valid
Samples may be held for longer periods only if the permittee, or monitoring laboratory,
has data on file to show that the specific types of sample under study are stable for the
longer time, and has received a variance from the Regional Administrator Some samples
may not be stable for the maximum time period given in the table A permittee, or
monitoring laboratory, is obligated to hold the sample for a shorter time if knowledge
exists to show this is necessary to maintain sample stability
6 Should only be used in the presence of residual chlorine
xix
-------
Maximum holding time is 24 hours when sulfide is present Optionally, all samples may
be tested with lead acetate paper before the pH adjustment in order to determine if sulfide
is piesent If sulfide is present, it can be removed by the addition of cadmium nitrate
powder until a negative spot test is obtained The sample is filtered and then NaOH is
added to pH 12
Samples should be filtered immediately on-site before adding preservative for dissolved
metals
For samples fiom non-chlorinated drinking water supplies cone HzSO4 should be added
to lower sample pH to less than 2 The sample should be analyzed before 14 days
x,x
-------
ENVIRONMENTAL PROTECTION AGENCY
REGIONAL QUALITY ASSURANCE COORDINATORS
REGION I
Warren H Oldaker
Central Regional Laboratory
Environmental Services Division
60 Westview Street
Lexington, MA 02173
FTS 671-6700
COML 617-671-6700
REGION II
Gerald F McKenna
Research and Quality Assurance
Branch
Environmental Services Division
Edison, NJ 08837
FTS 340-6645
COML 201-321-6645
REGION HI
Charles Jones, Jr
(3SA60)
Water Quality Monitoring Branch
Environmental Services Division
6th & Walnut Streets, Curtis Bldg
Philadelphia, PA 19106
FTS 597-9162
COML 215-597-9162
REGION IV
Wade Knight
Laboratory Services Branch
Environmental Services Division
College Station Road
Athens, GA 30613
FTS 250-3165
COML 404-546-3165
REGION V
David Payne
Quality Assurance Office
Environmental Services Division
536 South Clark Street
Chicago, IL 60605
FTS 353-7712
COML 312-353-7712
REGION VI
El oy R Lozano
Environmental Services Division
1201 Elm St, First Int'l Bldg
Dallas, TX 75270
FTS 729-2697
COML 214-767-2697
REGION VII
Charles P Hensley
Laboratory Branch
Environmental Services Division
25 Funston Road
Kansas City, KS 66115
FTS 758-4285
COML 816-374-4285
REGION VIII
Juanita Hillman
Environmental Services Division
Lincoln Tower Bldg , Suite 900
1860 Lincoln Street
Denver, CO 80295
FTS 327-4935
COML 303-837-4935
REGION IX
Ho Lee Young
Office of Quality Assurance
and Monitoring Systems
215 Fremont Street
San Francisco, CA 94105
FTS 454-8002
COML 415-556-8002
REGION X
Barry Townes
Environmental Services Division
1200 Sixth Avenue
Seattle, WA 98101
FTS 399-1675
COML 206-442-1675
XXI
-------
COLOR
Method 110.1 (Colorimetric, ADMI)
STORET NOS.
00082 at pH 7.6
00083 at ORIGINAL SAMPLE pH
Scope and Application
1 1 This method is applicable to colored waters and waste that have color characteristics
significantly different from the yellow platinum-cobalt standard
12 A working range of 25 to 250 color units is recommended Sample values above 250 units
may be determined by quantitative dilution
Summary of Method
2 1 This method is an extension of the Tnstimulus Filter Method1 Tnstimulus values are
converted to an ADMI single number color difference, of the same magnitude assigned
to platinum-cobalt standards, using the Adams Nickerson Color Difference (DE)
22 Tnstimulus values obtained by Spectrophotometnc Method 204B1 may be used to
calculate ADMI values as outlined m this procedure under Calculation 9 2
Interferences
3 1 Since very slight amounts of turbidity interfere with the determination, turbid samples
must be filtered prior to analysis The optimum filter media to remove turbidity without
removing color has not been found Membrane and glass fiber filters with functional pore
sizes of approximately 0 45 u are convenient to use Other techniques such as
centnfuging and/or filter aids may be used
Sample Handling and Preservation
4 1 Since biological activity may change the color characteristics of a sample, the
determination should be made as soon as possible Refrigeration at 4°C is recommended
Calibration
5 1 Standard curves must be established (as outlined in Procedure 8 3) for each photometer
used, and are not interchangeable For color values less than 250, a 5 cm cell path is
recommended Less than 5 cm cell paths may be used if calibration is performed with the
shorter cell
Apparatus
6 1 Spectrophotometer or filter photometer capable of transmission measurements using
tnstimulus filters listed below
Approved for NPDES
Issued 1978
1101-1
-------
Filter number Wavelength of maximum Corning designation*
transmittance m nm
1 590 CS 3-107
2 , 540 CS 4-98
3 438 CS 5-70
*Available from Corning Glass Works, Optical Products Department,
Corning, NY 14830
7. Reagents
7 1 Standard chloroplatmate solution Dissolve 1 246 g potassium chloroplatmate, K2PtQ6,
(equivalent to 0 500 g metallic Pt) and 1 g crystalline cobaltous chloride, CoCl2«6H2O, m
distilled water containing 100 ml of cone HC1 Dilute to 1000 ml with distilled water
This standard solution is defined as 500 ADMI color units
7.2 Sulfunc acid, concentrated
7.3 Sodium hydroxide, 10 N Dissolve 40 g of sodium hydroxide m 80 ml of distilled water
Cool to room temperature and dilute to 100 ml with distilled water
8. Procedure
8 1 Prepare two 100 ml volumes of sample by maintaining the original pH of one aliquot and
adjusting the second aliquot as necessary to pH 7 6 with sulfunc acid (7 2) or sodium
hydroxide (7 3)
8 2 Filter samples to remove turbidity through a 0 45 u membrane filter, glass fiber filter or
other suitable media (see interferences 3 1)
8 3 Use distilled water to set the transmittance at 100% and then determine the
transmittance of the clarified sample or standard with each of the three tnstimulus
filters Calibration standards from 25 to 250 units are recommended
9. Calculations
9.1 Calculate intermediate tnstimulus values for samples and standards from the
transmittance data in 8 3 using the following equations
Xs = (T3 x 0 1899) + (Tj x 0 791)
Zs = T3x 11835
where
TI = transmittance value in % using filter number 1
T2 = transmittance value in % using filter number 2
110 1-2
-------
T3 = transmittance value m % using filter number 3
9 2 Convert tnstimulus values to the corresponding Munsell values Vx, Vy and Vz by the use
of published tables2'3'4, or the equation suggested by Bndgeman5
9 3 Calculate DE values for samples and standards, construct a calibration curve by plotting
DE against ADMI units of standards and determine ADMI color units of samples from
the calibration curve
DE = M [0 23 X (V,, - V,)]2 + [(V, - V,c) - (V~ - V,,)]2 + [04[(V,C - V2C) - (Vys - ¥
where Vxs, Vys and Vzs = the Munsell values for Xs, Ys and Zs respectively and Vxc, Vyc
and Vzc = the Munsell values for a blank solution whose tnstimulus values are Xc, Y0
andZc
NOTE 1: If the photometer used is set at 100% transmittance with distilled water, the
tnstimulus values for the blank are 9809, 10000 and 11835 for Xc, Yc and Zc
respectively If necessary, tnstimulus values for the blank are determined as in
calculation (9 1)
9 4 Report ADMI color values at pH 7 6 and at the original pH
NOTE 2: The intermediate tnstimulus values calculated under 9 1, using the three
tnstimulus filters, are used only to calculate the ADMI color value They should not be
reported as tristimulus values or used to determine dominant wavelength, luminance and
punty
10 Precision and Accuracy
101 Accuracy data on actual samples cannot be obtained
10 2 Precision data are not available at this time
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, 14th Edition (1975), p 64
2 J Soc Dyers and Colorists, 86, No 8, 354 (1970)
3 Wys/,ecki and Stiles, Color Science, Wiley, N Y, 1967, Tables 6 4 A, B and C
4 Judd and Wyszecki, Color in Business, Science and Industry, 2nd Edition, Wiley, N Y (1963)
Tables A, B and C m Appendix
5 J Opt Soc Am , Volume 53, page 499, Apnl 1963
6. Dyes and the Environment-Report on Selected Dyes and Their Effects, Volume 1, Sept 1973
Appendix, American Dye Manufacturers Institute, Inc
1101-3
-------
COLOR
Method 110.2 (Colorimetric-Platinum-Cobalt)
STORET NOS.
TRUE COLOR 00080
APPARENT COLOR 00081
Scope and Application
1 1 The Platinum-Cobalt method is useful for measuring color of water derived from
naturally occurring materials, i e , vegetable residues such as leaves, barks, roots, humus
and peat materials The method is not applicable to color measurement on waters
containing highly colored industrial wastes See ADMI color method m this manual
NOTE 1. The Spectrophotometric and Tnstimulus methods are useful for detecting
specific color problems The use of these methods, however, is laborious and unless
determination of the hue, purity, and luminance is desired, they are of limited value
Summary of Method
2 1 Color is measured by visual comparison of the sample with platinum-cobalt standards
One unit of color is that produced by 1 mg/1 platinum in the form of the chloroplatmate
ion
Interferences
3 1 Since very slight amounts of turbidity interfere with the determination, samples showing
visible turbidity should be clarified by centnfugation
3 2 Method is pH dependent
Sample Handling and Preservation
4 1 Representative samples shall be taken in scrupulously clean glassware
42 Since biological activity may change the color characteristics of a sample, the
determination should be made as soon as possible Refrigeration at 4°C is recommended
Apparatus
5 1 Nessler tubes Matched, tall form, 50 ml capacity
Reagents
6 1 Standard chloroplatmate solution Dissolve 1 246 g potassium chloroplatmate, K2PtCl6,
(equivalent to 0 500 g metallic Pt) and 1 g crystalline cobaltous chloride, CoC12»H2O, in
distilled water containing 100 ml of cone HC1 Dilute to 1000 ml with distilled water
This standard solution is equivalent to 500 color units
Preparation of Standards
7 1 Prepare standards in increments from 5 to 70 units The following series is suggested
Approved for NPDES
Issued 1971
1102-1
-------
Ml of Standard Solution
Diluted to 500 ml Color in
with Distilled Water Chloroplatmate Units
00 0
05 5
10 10
15 15
20 20
25 25
30 30
35 35
40 40
45 45
50 50
60 60
70 70
7.2 Protect these standards against evaporation and contamination by use of clean, inert
stoppers
NOTE 2: The standards also must be protected against the absorption of ammonia since
an increase in color will result
8. Procedure
8 1 Apparent color Observe the color of the sample by filling a matched Nessler tube to the
50 ml mark with the water and compare with standards This comparison is made by
looking vertically downward through the tubes toward a white or specular surface placed
at such an angle that light is reflected upward through the columns of liquid If turbidity
has not been removed by the procedure given m (8 2), report the color as "appaient
color" If the color exceeds 70 units, dilute the sample with distilled water m known
proportions until the color is within the range of the standards
8.2 True color Remove turbidity by centnfuging the sample until the supernatant is clear
The time required will depend upon the nature of the sample, the speed of the motor, and
the radius of the centrifuge, but rarely will more than one hour be necessary Compare
the centnfuged sample with distilled water to insure that turbidity has been removed If
the sample is clear, then compare with standards as given m (8 1)
9. Calculation
9.1 Calculate the color units by means of the following equation
Color units = A * S0
where
A = estimated color of diluted sample
V = ml sample taken for dilution
1102-2
-------
9 2 Report the results m whole numbers as follows
Color Units Record to Nearest
1-50 1
51-100 5
101-250 10
251-500 20
10 Precision and Accuracy
101 Precision and accuracy data are not available at this time
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 64, Method
204A(1975)
110 2-3
-------
COLOR
Method 110.3 (Spectrophotometric)
STORET NO. 00080
Scope and Application
1 1 This method is applicable to drinking, surface, and saline waters, domestic and industrial
wastes It must be used for industrial wastes that cannot be determined by the Platinum-
Cobalt method
Summary of Method
2 1 Color characteristics are measured at pH 7 6 and at the original pH by obtaining the
visible absorption spectrum of the sample on a spectrophotometer The percent
transmission at certain selected wavelengths is used to calculate the results
2 2 The results are expressed in terms of dominant wavelength, hue, luminance, and purity
Interferences
3 1 Since very slight amounts of turbidity interfere with the determination, samples must be
filtered before analysis
Sample Handling and Preservation
4 1 Since biological activity may change the color characteristics of a sample, the
determination should be made as soon as possible Refrigeration at 4°C is recommended
Reference
5 1 The procedure to be used for this determination is found in
Standard Methods for the Examination of Water and Wastewater, 14th Edition,
p 66, Method 204B (1975)
Approved for NPDES
Issued 1974
1103-1
-------
CONDUCTANCE
Method 120.1 (Specific Conductance, umhos at 25°Q
STORET NO. 00095
1 Scope and Application
1 1 This method is applicable to drinking, surface, and saline wates, domestic and indus-
trial wastes and acid rain (atmospheric deposition)
2 Summary of Method
2 1 The specific conductance of a sample is measured by use of a self-contained conductivity
meter, Wheatstone bridge-type, or equivalent
2 2 Samples are preferable analyzed at 25°C If not, temprature corrections aremade and
results reported at 25°C
3 Comments
3 1 Instrument must be standardized with KC1 solution before daily use
3 2 Conductivity cell must be kept clean
3 3 Field measurements with comparable instruments are reliable
3 4 Temperature variations and corrections represent the largest source of potential error
4 Sample Handling and Preservation
4 1 Analyses can be performed either in the field or laboratory
42 If analysis is not completed within 24 hours of sample collection, sample should be
filtered through a 0 45 micron filter and stored at 4°C Filter and apparatus must be
washed with high quality distilled water and pre-rmsed with sample before use
5 Apparatus
5 1 Conductivity bridge, range 1 to 1000 jumho per centimeter
5 2 Conductivity cell, cell constant 1 0 or micro dipping type cell with 1 0 constant YSI
#3403 or equivalent
5 4 Thermometer
6 Reagents
6 1 Standard potassium chloride solutions, 0 01 M Dissolve 0 7456 gm of pre-dried (2 hour
at 105°C) KC1 in distilled water and dilute to 1 liter at 25°C
7 Cell Calibration
7 1 The analyst should use the standard potassium chloride solution (6 1) and the table
below to check the accuracy of the cell constant and conductivity bridge
Approved for NPDES
Issued 1971
Editorial revision, 1982
120 1-1
-------
Conductivity 0 01 m KC1
°C
Micromhos/cm
10.
21
22
23
24
25
26
27
28
1305
1332
1359
1386
1413
1441
1468
1496
Procedure
8.1 Follow the direction of the manufacturer for the operation of the instrument
8 2 Allow samples to come to room temperature (23 to 27°C), if possible
8.3 Determine the temperature of samples within 0 5°C If the temperature of the samples
is not 25°C, make temperature correction in accordance with the instruction in Section
9 to convert reading to 25°
Calculation
9 1 These temperature corrections are based on the standard KC1 solution
9.1 1 If the temperature of the sample is below 25°C, add 2% of the reading per degree
912 If the temperature is above 25°C, subtract 2% of the reading per degree
9.2 Report results as Specific Conductance, //mhos/cm at 25°
Precision and Accuracy
10.1 Forty-one analysts in 17 laboratories analyzed six synthetic water samples containing
increments of inorganic salts, with the following results
Increment as
Specific Conductance
100
106
808
848
1640
1710
Precision as
Standard Deviation
755
814
661
796
106
119
(FWPCA Method Study 1, Mineral and Physical Analyses )
Bias,
-202
-076
-363
-454
-536
-508
Accuracy as
Bias,
omhos/cm
-20
-08
-293
-385
-879
-869
10 2 In a single laboratory (EMSL) using surface water samples with an average
conductivity of 536 //mhos/cm at 25°C, the standard deviation was ±6
120 1-2
-------
Bibliography
1 The procedure to be used for this determination is found in
Annual Book of ASTM Standards Part 31, "Water," Standard Dl 125-64, p 120 (1976)
2 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 71,
Method 205 (1975)
3 Instruction Manual for YSI Model 31 Conductivity Bridge
4 Peden, M E , and Skowron "Ionic Stability of Precipitation Samples," Atmospheric
Environment, Vol 12, p 2343-2344, 1978
120 1-3
-------
HARDNESS, Total (mg/1 as CaCO3)
Method 130.1 (Colorimetric, Automated EDTA)
STORET NO. 00900
Scope and Application
1 1 This automated method is applicable to drinking, surface, and saline waters The
applicable range is 10 to 400 mg/1 as CaCO3 Approximately 12 samples per hour can be
analyzed
Summary of Method
2 1 The magnesium EDTA exchanges magnesium on an equivalent basis for any calcium
and/or other cations to form a more stable EDTA chelate than magnesium The free
magnesium reacts with calmagite at a pH of 10 to give a red-violet complex Thus, by
measuring only magnesium concentration in the final reaction stream, an accurate
measurement of total hardness is possible
Sample Handling and Preservation
3 1 Cool to 4°C, HNO3 to pH < 2
Interferences
4 1 No significant interferences
Apparatus
5 1 Techmcon AutoAnalyzer consisting of
511 Sampler I
5 12 Continuous Filter
5 1 3 Manifold
514 Proportioning Pump
515 Colorimeter equipped with 15 mm tubular flow cell and 520 nm filters
516 Recorder equipped with range expander
Reagents
6 1 Buffer Dissolve 67 6 g NH4C1 in 572 ml of NH4OH and dilute to 1 liter with distilled
water
6 2 Calmagite Indicator Dissolve 0 25 g m 500 ml of distilled water by stirring
approximately 30 minutes on a magnetic stirrer Filter
6 3 Monomagnesium ethylenediamme-tetraacetate (MgEDTA) Dissolve 0 2 g of MgEDTA
in 1 liter of distilled water
6 4 Stock Solution Weigh 1 000 g of calcium carbonate (pre-dned at 105°C) into 500 ml
Erlenmeyer flask, add 1 1 HC1 until all CaCO3 has dissolved Add 200 ml of distilled
water and boil for a few minutes Cool, add a few drops of methyl red indicator, and
adjust to the orange color with 3N NH4OH and dilute to 1000 ml with distilled water 1 0
ml=10mgCaCO3
Approved for NPDES
Issued 1971
130 1-1
-------
641 Dilute each of the following volumes of stock solutions to 250 ml in a volumetric
flask for appropriate standards
Stock Solution, ml CaCO3, mg/1
25 ' 100
50 200
10 0 40 0
150 60 0
25 0 100 0
35 0 140 0
50 0 200 0
75 0 300 0
100 0 400 0
6 5 Ammonium Hydroxide, IN Dilute 70 ml of cone NH4OH to 1 later with distilled water
7. Procedure
71 Pretreatment
711 For drinking waters, surface waters, saline waters, and dilutions thereof, no
pretreatment steps are necessary Proceed to 7 2
712 For most wastewaters, and highly polluted waters, the sample must be digested as
given in the Atomic Absorption Methods section of this manual, paragraphs 413
and 414 Following this digestion, proceed to 7 2
7 2 Neutralize 50 0 ml of sample with IN ammonium hydroxide (6 5) and note volume of
NH4OHused
7 3 Set up manifold as shown in Figure 1
7 4 Allow both colorimeter and recorder to warm up for 30 minutes Run a baseline with all
reagents, feeding distilled water through the sample line Adjust dark current and
operative opening on colorimeter to obtain stable baseline
7 5 Place distilled water wash tubes in alternate openings in Sampler and set sample timing
at 2 5 minutes
7 6 Arrange working standards in Sampler in order of decreasing concentrations Complete
loading of Sampler tray with unknown samples
7.7 Switch sample line from distilled water to Sampler and begin analysis
8. Calculation
8 1 Prepare standard cun'e by plotting peak heights of processed standards against
concentration values Compute concentration of samples by comparing sample peak
heights with standard curve Correct for amount of NH4OH used in 7 2 as follows
mg/1 = ^x B
where;
A= Vol of sample plus volume of NH4OH
B = Concentration from standard curve
130 1-2
-------
9 Precision and Accuracy
91 In a single laboratory (EMSL), using surface water samples at concentrations of 19, 120,
385, and 366 mg/1 as CaCO3, the standard deviations were ±15, ±15, ±4 5, and ±50,
respectively
92 In a single laboratory (EMSL), using surface water samples at concentrations of 39 and
296 mg/1 as CaCO3, recoveries were 89% and 93%, respectively
Bibliography
1 Techmcon AutoAnalyzer Methodology, Bulletin No 2/Techmcon Controls, Inc , Chauncey,
New York (July 1960)
2 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 202,
Method 309B (1975)
130 1-3
-------
8- =
( o
vlx
CO C9
LU
1—
CO
in
CO
CO
at x =
•< — C3
_i X cj>
00000000
CD
130 1-4
-------
HARDNESS, Total (mg/1 as CaCO3)
Method 130.2 (Titrimetric, EDTA)
STORET NO. 00900
Scope and Application
1 1 This method is applicable to drinking, surface, and saline waters, domestic and industrial
wastes
1 2 The method is suitable for all concentration ranges of hardness, however, in order to
avoid large titration volumes, use a sample aliquot containing not more than 25 mg
CaCO3
1 3 Automated titration may be used
Summary of Method
2 1 Calcium and magnesium ions in the sample are sequestered upon the addition of
disodium ethylenediamme tetraacetate (Na2EDTA) The end point of the reaction is
detected by means of Enochrome Black T indicator, which has a red color in the
presence of calcium and magnesium and a blue color when the cations are sequestered
Sample Handling and Preservation
3 1 Cool to 4°C, HNO3 to pH < 2
Comments
4 1 Excessive amounts of heavy metals can interfere This is usually overcome by
complexing the metals with cyanide
411 Routine addition of sodium cyanide solution (Caution deadly poison) to prevent
potential metallic interference is recommended
Apparatus
5 1 Standard laboratory titnmetnc equipment
Reagents
6.1 Buffer solution
6 1 1 If magnesium EDTA is available Dissolve, 16 9 g NH4C1 in 143 ml cone
NH4OH in a 250 ml volumetric, add 1 25 g of magnesium salt of EDTA and dilute
to the mark with distilled water Then go to 6 1 3
612 If magnesium EDTA is unavailable Dissolve 1 179 g disodium EDTA (analytical
reagent grade) and 780 mg MgSO4»7H2O (or 644 mg MgCl2«6H2O) in 50 ml
distilled water Add this solution to a 250 ml volumetric flask containing 16 9 g
NH4C1 and 143 ml cone NH4OH with mixing and dilute to the mark with
distilled water
613 Store in a tightly stoppered plastic bottle, stable for approximately one month
Dispense with bulb operated pipet Discard when 1 or 2 ml added to sample fails to
produce a pH of 10 0 ±01 at end point of titration
Approved for NPDES
Issued 1971
Editorial revision 1978 and 1982
130 2-1
-------
614 Commercially available "odorless buffers" which are more stable, may be used
6.2 Inhibitors For most waters inhibitors are not necessary If interfering ions are present
use one of the following
621 Inhibitor I NaCN powder (Caution extremely poisonous) Flush solutions or
sample containing this down dram using large quantities of water Make sure no
acids are present which might liberate HCN gas
6.2 2 Inhibitor II Dissolve 5 0 g Na2S-9 H2O or 3 7 g Na2S»5 H2O in 100 ml distilled
water Exclude air with tightly fitted rubber stopper This gives sulfide precipitates
which may obscure the end point if large quantities of heavy metals are present
Deteriorates rapidly through air oxidation
623 Inhibitor III Dissolve 4 5 g hydroxylamme hydrochlonde in 100 ml of 95%
ethanol or isopropanol
6 3 Indicator Use a commercially available indicator such as Calmagite indicator
(Malhnckrodt) or one of the formulations descnbed below (6 3 1-6 3 3)
6.3 1 Mix 0 5 g Enochrome Black T with 4 5 g hydroxylamme hydrochlonde Dissolve
in 100 ml of 95% ethanol or isopropanol
632 Dissolve 0 5 to 1 0 g Enochrome Black T in an appropnate solvent such as
tnethanolamme or 2-methoxyethanol Stable approximately one week
633 Mix together 0 5 g Enochrome Black T and 100 g NaCl
64 Standard EDTA titrant, 0 02 N 'Place 3 723 g analytical reagent grade disodium
ethylenediamme tetraacetate dihydrate, Na2H2C10H12O8N2»2 H2O in a 1 liter volumetric
flask and dilute to the mark with distilled water Check with standard calcium solution
(6 4 1) by titration (6 4 5) Store in polyethylene Check penodically because of gradual
detenoration
64.1 Standard calcium solution 0 02 N Place 1 000 g anhydrous calcium carbonate
(primary standard low in metals) in a 500 ml flask Add, a little at a time, 1 +1
HCL (6 4 2) until all of the CaCO3 has dissolved Add 200 ml distilled water
Boil for a few minutes to expel COa Cool Add a few drops of methyl red
indicator (6 4 3) and adjust to intermediate orange color by adding 3N
NH4OH (6 4 4) or 1 + 1 HC1 (6 4 2) as required Quantitatively transfer to a
1 liter volumetric flask and dilute to mark with distilled water
642 Hydrochlonc acid solution, 1 + 1
643 Methyl red indicator Dissolve 0 10 g methyl red in distilled water in a 100 ml
volumetric flask and dilute to the mark
644 Ammonium hydroxide solution, 3 N Dilute 210 ml of cone NH4OH to 1 liter with
distilled water
645 Standardization titration procedure Place 10 0 ml standard calcium solution
(6 4 1) in vessel containing about 50 ml distilled water Add 1ml buffer solution
(6 1) Add 1-2 drops indicator (6 3) or small scoop of dry indicator (6 3 3) Titrate
slowly with continuous stirnng until the last reddisl^ tinge disappears, adding last
130 2-2
-------
few drops at 3-5 second intervals At end point the color is blue Total titration
duration should be 5 minutes from the time of buffer addition
N of EDTA =
. f.~A
ml of EDTA
6 5 Ammonium Hydroxide, IN Dilute 70 ml of cone NH4OHto 1 liter with distilled water
Procedure
7 1 Pretreatment
711 For drinking waters, surface waters, saline waters, and dilutions thereof, no
pretreatment steps are necessary Proceed to 7 2
712 For most wastewaters, and highly polluted waters, the sample must be digested as
given in the Atomic Absorption Methods section of this manual, paragraphs 413
and 414 Following this digestion, proceed to 7 2
7 2 Titration of sample-normal to high hardness
721 Sample should require <15 ml EDTA titrant (64) and titration should be
completed within 5 minutes of buffer addition
722 Place 25 0 ml sample in titration vessels, neutralize with IN ammonium hydroxide
(6 5) and dilute to about 50 ml
723 Add 1 to 2 ml buffer solution (6 1)
724 If end point is not sharp (as determined by practice run) add inhibitor at this point
(see 7 4)
725 Add 1 to 2 drops indicator solution (63 1 or 6 3 2) or small scoop of dried powder
indicator formulation (6 3 3)
726 Titrate slowly with continuous stirring with standard EDTA titrant (6 4) until last
reddish tint disappears Solution is normally blue at end point
7 3 Titration of sample-low hardness (less than 5 mg/1)
731 Use a larger sample (100 ml)
732 Use proportionately larger amounts of buffer, inhibitor and indicator
733 Use a microburet and run a blank using redistilled, distilled or deiomzed water
7 4 To correct for interferences
741 Some metal ions interfere by causing fading or indistinct end points Inhibitors
reduce this in accord with the scheme below for 25 0 ml samples diluted to 50 ml
130 2-3
-------
Interfering
Substance
Maximum Concentrations of Interferences Permissible
with Various Inhibitors8
Maximum Interference
Concentration mg/1
Aluminum
Barium
Cadmium
Cobalt
Copper
Iron
Lead
Manganese (Mn2+)
Nickel
Strontium
Zinc
Polyphosphate
Inhibitor I
20
b
b
over 20
over 30
over 30
b
b
over 20
b
b
a Based on 25-ml sample diluted to 50
b Titrates as hardness
c Inhibitor fails if substance is present
Inhibitor II
20
b
20
03
20
5
20
1
03
b
200
10
ml
Inhibitor III
20
b
b
DC
03
20
b
1
Oc
b
b
742 Inhibitor I At step 7 2 4 add 250 mg NaCN Add sufficient buffer to achieve pH
10 0 ± 0 1 to offset alkalinity resulting from hydrolysis of sodium cyanide
7.4 3 Inhibitor II At step 7 2 4 add 1 ml of inhibitor II (6 2 2)
744 Inhibitor III At step 7 2 4 add 1 ml of inhibitor III (6 2 3)
Calculations
Hardness (EDTA) pi A x N x 50,000
mg CaCO3/! g ml sample
where
A = ml EDTA titrant (6 4)
N = normality of EDTA titrant
1302-4
-------
Precision and Accuracy
9 1 Forty-three analysts in nineteen laboratories analyzed six synthetic water samples
containing exact increments of calcium and magnesium salts, with the following results
Increment as
Total Hardness
mg/liter, CaCO3
Precision as
Standard Deviation
mg/hter, CaCO3
Accuracy as
Bias, Bias,
% mg/hter, CaCO3
31
33
182
194
417
444
287
252
487
298
965
973
-087
-073
-019
-104
-335
-323
-0003
-024
-04
-20
-130
-143
(FWPCA Method Study 1, Mineral and Physical Analyses)
92 In a single laboratory (EMSL), using surface water samples at an average concentration
of 194 mg CaCO3/1, the standard deviation was ± 3
93 A synthetic unknown sample containing 610 mg/1 total hardness as CaCO3 contributed
by 108 mg/1 Ca and 82 mg/1 Mg, and the following supplementary substances 3 1 mg/1
K, 19 9 mg/1 Na, 241 mg/1 chloride, 0 25 mg/1 nitrite N, 1 1 mg/1 nitrate N, 259 mg/1
sulfate, and 42 5 mg/1 total alkalinity (contributed by NaHCO3) in distilled water was
analyzed m 56 laboratories by the EDTA titnmetnc method with a relative standard
deviation of 2 9% and a relative error of 0 8%
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 202,
Method 309B (1975) '
2 Annual Book of ASTM Standards, Part 31, "Water", Standard D 1126-67, p 161, Method B
(1976)
130 2-5
-------
ODOR
Method 140.1 (Threshold Odor, Consistent Series)
STORET NO. 60°C: 00086
Room Temp: 00085
Scope and Application
1 1 This method is applicable to the determination of threshold odor of drinking, surface,
and saline waters, domestic and industrial wastes
1 2 Highly odorous samples are reduced in concentration proportionately before being
tested Thus, the method is applicable to samples ranging from nearly odorless natural
waters to industrial wastes with threshold odor numbers in the thousands
Summary of Method"'
2 1 The sample of water is diluted with odor-free water until a dilution that is of the least
definitely perceptible odor to each tester is found The resulting ratio by which the
sample has been diluted is called the "threshold odor number" (TON)
2 2 People vary widely as to odor sensitivity, and even the same person will not be consistent
in the concentrations they can detect from day to day Therefore, panels of not less than
five persons, and preferably 10 or more, are recommended to overcome the variability of
using one observer m As an absolute minimum, two persons are necessary One to make
the sample dilutions and one to determine the threshold odor
Sample Handling and Preservation
3 1 Water samples must be collected m glass bottles with glass or Teflon-lined closures
Plastic containers are not reliable for odor samples and must not be used
3 2 Odor tests should be completed as soon as possible after collection of the sample If
storage is necessary, collect at least 1000 ml of sample in a bottle filled to the top
Refrigerate, making sure no extraneous odors can be drawn into the sample as the water
cools
Interferences
4 1 Most tap waters and some waste waters are chlorinated It is often desirable to determine
the odor of the chlorinated sample as well as of the same sample after removal of
chlorine Dechlormation is achieved using sodium thiosulfate in exact stoichiometnc
quantity
411 It is important to check a blank to which a similar amount of dechlonnating agent
has been added to determine if any odor has been imparted Such odor usually
disappears upon standing if excess reagent has not been added
Apparatus
5 1 Odor-free glassware Glassware must be freshly cleaned shortly before use, with non-
odorous soap and acid cleaning solution followed by rinsing with odor-free water (6 1)
Issued 1971
140 1-1
-------
Glassware used in odor testing should be reserved for that purpose only Rubber, cork,
and plastic stoppers must not be used
5 2 Constant temperature bath A water bath or electric hotplate capable of maintaining a
temperature control of ± 1°C for performing the odor test at 60°C The temperature bath
must not contribute any odor to the odor flasks
5 3 Odor flasks Glass stoppered 500 ml (1)32) Erlenmeyer flasks, or wide-mouthed 500 ml
Erlenmeyer flasks equipped with Petn dishes a$ cover plates
NOTE: Narrow-mouth vessels are not suitable for running odor tests Potential positive
bias due to color and/or turbidity of water sample under observation can be eliminated
by wrapping odor flasks in aluminum foil, painting flasks with non-odorous paint, or by
using red actinic Erlenmeyer flasks
5 4 Sample bottles Glass bottles with glass or Teflon-lined closures
5.5 Pipets, measuring 10 0 and 1 0 ml graduated in tenths
5.6 Graduated cylinders 250,200,100, 50, and 25 ml
5 7 Thermometer 0-110°C (± 1°C), chemical or metal stem dial type
5.8 Odor-free water generator See Figure 1
6. Reagents
6 1 Odor-free water Odor-free dilution water must be prepared as needed by filtration
through a bed of activated carbon Most tap waters are suitable for preparation of odor-
free waters, except that it is necessary to check the filtered water for chlorine residual,
unusual salt concentrations, or unusually high or low pH All these may affect some
odorous samples
Where supplies are adequate, distilled water avoids these problems as a source of odor-
free water A convenient odor-free water generator may be made as shown in Figure 1
Pass tap or distilled water through the odor-free water generator at a rate of 0 1
liter/minute When the generator is first started, it should be flushed to remove carbon
fines before the odor-free water is used
611 The quality of water obtained from the odor-free water generator should be
checked daily at the temperature tests are to be conducted (room temperature
and/or 60°C) The life of the carbon will vary with the condition and amount of
water filtered Subtle odors of biological origin are often found if moist carbon
filters are permitted to stand idle between test periods Detection of odor in the
water coming through the carbon indicates a change of carbon is needed
7 Procedure
7 1 Precaution Selection of persons to make odor tests should be carefully made Extreme
sensitivity is not required, but insensitive persons should not be used A good observer
has a sincere interest in the test Extraneous odor stimuli such as those caused by
smoking and eating prior to the test or through the use of scented soaps, perfumes, and
shaving lotions must be avoided The tester should be free from colds or allergies that
affect odor-response Frequent rests in an odor-free atmosphere are recommended The
room in which the tests are to be conducted should be free from distractions, drafts, and
other odor In certain industrial atmospheres, a special odor-free room may be required,
ventilated by air filtered through activated carbon and maintained at a constant
140 1-2
-------
comfortable temperature and humidity For precise work a panel of five or more testers
should be used The persons making the odor measurements should not prepare the
samples and should not know the dilution concentrations being evaluated These persons
should have been made familiar with the procedure before participating in a panel test
Always start.with the most dilute sample to avoid tiring the senses with the concentrated
sample The temperature of the samples during testing should be kept within 1 degree of
the specified temperature for the test
7 2 Threshold measurement The ratio by which the odor-bearing sample has to be diluted
with odor-free water for the odor to be just detectable by the odor test is the "threshold
odor number" (TON) The total volume of sample and odor-free water used in each
test is 200 ml The proper volume of odor-free water is put into the flask first, the sample
is then added to the water Table 1 gives the dilutions and corresponding threshold
numbers
Table 1
Threshold Odor Number
Corresponding to Various Dilutions
Sample Volume (ml) Threshold Odor
Diluted to 200 ml Number
200 1
100 2
50 4
25 8
125 16
63 32
31 64
16 128
08 256
7 3 Determine the approximate range of the threshold odor by
7 3 1 Adding 200 ml, 50 ml, 12 5 ml, and 3 1 ml of the sample to separate 500 ml glass-
stoppered Erlenmeyer flasks containing odor-free water to make a total volume of
200 ml A separate flask containing only odor-free water serves as the reference for
comparison If run at 60'C, heat the dilutions and the reference in the constant
temperature bath at 60°C (± 1°C)
732 Shake the flask containing the odor-free water, remove the stopper, and sniff the
vapors Test the sample containing the least amount of odor-bearing water m the
same way If odor can be detected in this dilution, more dilute samples must be
prepared as described in (7 3 3) If odor cannot be detected in the first dilution,
repeat the above procedure using the sample containing the next higher
concentration of the odor-bearing watei, and continue this process until odor is
clearly detected
140 1-3
-------
2 HOLE
RUBBER STOPPER
WtitfM
r&'iWj&
% ,,
•**
'*
"w
GRANULAR
4 x 10-MESH
ACTIVATED
CARBON
PEA SIZE
GRAVEL
FIGURE 1. ODOR-FREE WATER GENERATOR
140 1-4
-------
7 3 3 If the sample being tested requires more extensive dilution than is provided by
Table 1, an intermediate dilution is prepared from 20 ml of sample diluted to 200
ml with odor-free water Use this dilution for the threshold determination
Multiply the T O N obtained by ten to correct for the intermediate dilution In
rare cases more than one tenfold intermediate dilution step may be required
7 4 Based on the results obtained in the preliminary test, prepare a set of dilutions using
Table 2 as a guide One or more blanks aie inserted in the series, in the vicinity of the
expected threshold, but avoiding any repeated pattern The observer does not know
which dilutions are odorous and which are blanks He smells each flask in sequence,
beginning with the least concentrated sample and comparing with a known flask of odor-
free water, until odor is detected with utmost certainty
Table 2
Dilutions for Various Odor Intensities
Sample Volume m Which Odor First Noted
200 ml 50 ml 12 5 ml 3 1 ml
Volume (ml) of Sample to be Diluted to 200 ml
200 100 50 (intermediate
100 50 25 Dilution
50 25 12 5 See 7 3 3)
25 12 5 63
125 63 31
7 5 Record the observations of each tester by indicating whether odor is noted (+ sign) in
each test flask
For example
ml sample
diluted to 200 ml 12 5 0 25 0 50 100 200
Response - - + - + + +
Calculations
8 1 The threshold odor number is the dilution ratio at which odor is just detectable In the
example above (7 5), the first detectable odor occurred when 25 ml sample was diluted to
200 ml Thus, the threshold is 200 divided by 25, equals 8 Table 1 lists the threshold odor
numbers that correspond to common dilutions
8 2 Anomalous responses sometimes occur, a low concentration may be called positive and a
higher concentration in the senes may be called negative In such a case, the threshold is
designated as that point of detection after which no further anomalies occur
140 1-5
-------
For instance
ml sample
diluted to 200 ml
63
125
0
25
50
100
Response +-- + + +
threshold I
Threshold
8 3 Calculations of panel results to find the most probable average threshold are best
accomplished by appropriate statistical methods For most purposes, the threshold of a
group can be expressed as the geometric mean of the individual thresholds The
geometric mean is calculated in the following manner
831 Obtain odor response as outlined m Procedure and record results
For example
ml of Odor-
free water
Table 3
Sample Odor Series
ml of
Sample
Observer Response*
3
188
175
200
150
200
100
0
125
25
0
50
0
100
200
*Circled plus equals threshold level
832 Obtain individual threshold odor numbers from Table 1
Observer
1
2
3
4
5
TON
4
8
2
2
8
8.3 3 The geometric mean is equal to the nth root of the product of n numbers
Therefore
4x8x2x2x8 = 1,024
and tf 1,024 = log 1,024 = 30103 = 0 6021
5 5
and anti-log of 0 6021 = 4 = T O N
140 1-6
-------
9 Precision and Accuracy
9 1 Precision and accuracy data are not available at this time
92 A threshold number is not a precise value In the case of the single observer, it represents
a judgment at the time of testing Panel results are more meaningful because individual
differences have less influence on the result One or two observers can develop useful data
if comparison with larger panels has been made to check their sensitivity Comparisons
of data from time to time or place to place should not be attempted unless all test
conditions have been carefully standardized and some basis for comparison of observer
intensities exists
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 75, Method
206, (1975)
2 ASTM, Comm E-18, STP 433, "Basic Principles of Sensory Evaluation", STP 434, Manual on
Sensory Testing Methods, STP 440, "Correlation of Subjective-Objective Methods in the Study
of Odors and Taste", Phil, Pennsylvania (1968)
3 Baker, R A, "Critical Evaluation of Olfactory Measurement" Jour WPCF, 34, 582 (1962)
140 1-7
-------
pH
Method 150.1 (Electrometric)
STORET NO.
Determined on site 00400
Laboratory 00403
1 Scope and Application
1 1 This method is applicable to drinking, surface, and saline waters, domestic and industrial
wastes and acid rain (atmospheric deposition)
2 Summary of Method
2 1 The pH of a sample is determined electrometncally using either a glass electrode in
combination with a reference potential or a combination electrode
3 Sample Handling and Preservation
3 1 Samples should be analyzed as soon as possible preferably in the field at the time of
sampling
3 2 High-purity waters and waters not at equilibrium with the atmosphere are subject to
changes when exposed to the atmosphere, therefore the sample containers should be
filled completely and kept sealed prior to analysis
4 Interferences
4 1 The glass electrode, in general, is not subject to solution interferences from color,
turbidity, colloidal matter, oxidants, reductants or high salinity
4 2 Sodium error at pH levels greater than 10 can be reduced or eliminated by using a "low
sodium error" electrode
4 3 Coatings of oily material or particulate matter can impair electrode response These
coatings can usually be removed by gentle wiping or detergent washing, followed by
distilled water rinsing An additional treatment with hydrochloric acid (1 + 9) may be
necessary to remove any remaining film
4 4 Temperature effects on the electrometnc measurement of pH arise from two sources
The first is caused by the change in electrode output at various temperatures This
interference can be controlled with instruments having temperature compensation or by
calibrating the electrode-instrument system at the temperature of the samples The
second source is the change of pH inherent in the sample at various temperatures This
error is sample dependent and cannot be controlled, it should therefore be noted by
reporting both the pH and temperature at the time of analysis
5 Apparatus
51 pH Meter-laboratory or field model A wide variety of instruments are commercially
available with vanous specifications and optional equipment
>
Approved for NPDES
Issued 1971
Editorial revision 1978 and 1982
150 1-1
-------
5 2 Glass electrode
5 3 Reference electrode-a calomel, silver-silver chloride or other reference electrode of
constant potential may be used
NOTE 1: Combination electrodes incorporating both measuring and reference
functions are convenient to use and are available with solid, gel type filling materials that
require minimal maintenance
5 4 Magnetic stirrer and Teflon-coated stirring bar
5 5 Thermometer or temperature sensor for automatic compensation
6 Reagents
6 1 Primary standard buffer salts are available from the National Bureau of Standards and
should be used in situations where extreme accuracy is necessary
6.1 1 Preparation of reference solutions from these salts require some special precautions
and handling0' such as low conductivity dilution water, drying ovens, and carbon
dioxide free purge gas These solutions should be replaced at least once each
month
6 2 Secondary standard buffers may be prepared from NBS salts or purchased as a solution
from commercial vendors Use of these commercially available solutions, that have been
validated by comparison to NBS standards, are recommended for routine use,
7. Calibration
7.1 Because of the wide variety of pH meters and accessories, detailed operating procedures
cannot be incorporated into this method Each analyst must be acquainted with the
operation of each system and familiar with all instrument functions Special attention to
care of the electrodes is recommended
7 2 Each instrument/electrode system must be calibrated at a minimum of two points that
bracket the expected pH of the samples and are approximately three pH units or more
apart
721 Various instrument designs may involve use of a "balance" or "standardize" dial
and/or a slope adjustment as outlined in the manufacturer's instructions Repeat
adjustments on successive portions of the two buffer solutions as outlined in
procedure 8 2 until readings are within 0 05 pH units of the buffer solution value
8 Procedure
8 1 Standardize the meter and electrode system as outlined in Section 7
8.2 Place the sample or buffer solution in a clean glass beaker using a sufficient volume to
cover the sensing elements of the electrodes and to give adequate clearance for the
magnetic stirring bar
821 If field measurements are being made the electrodes may be immersed directly in
the sample stream to an adequate depth and moved in a manner to insure sufficient
sample movement across the electrode sensing element as indicated by drift free
( < 0 1 pH) readings
83 If the sample temperature differs by more than 2°C from the buffer solution the measured
pH values must be corrected Instruments are equipped with automatic or manual
'"National Bureau of Standards Special Publication 260
150 1-2
-------
10
compensators that electronically adjust for temperature differences Refer to
manufacturer's instructions
8 4 After rinsing and gently wiping the electrodes, if necessary, immerse them into the
sample beaker or sample stream and stir at a constant rate to provide homogeneity and
suspension of solids Rate of stirring should minimize the air transfer rate at the air water
interface of the sample Note and record sample pH and temperature Repeat
measurement on successive volumes of sample until values differ by less than 0 1 pH
units Two or three volume changes are usually sufficient
8 5 For acid rain samples it is most important that the magnetic stirrer is not used
Instead, swirl the sample gently for a few seconds after the introduction of the
electrode(s) Allow the electrode(s) to equilibrate The air-water interface should
not be disturbed while measurement is being made If the sample is not in
equilibrium with the atmosphere, pH values will change as the
dissolved gases are either absorbed or desorbed Record sample pH and
temperature
Calculation
9 1 pH meters read directly in pH units Report pH to the nearest 0 1 unit and temperature
to the nearest °C
Precision and Accuracy
10 1 Forty-four analysts in twenty laboratories analyzed six synthetic water samples
containing exact increments of hydrogen-hydroxyl ions, with the following results
pH Units
35
35
71
72
80
80
Standard Deviation
pH Units
010
Oil
020
018
013
012
(FWPCA Method Study 1, Mineral and Physical Analyses)
Bias,
%
Accuracy as
-029
-000
+ 101
-003
-012
+016
Bias,
pH Units
-001
+007
-0002
-001
+001
102 In a single laboratory (EMSL), using surface water samples at an average pH of 7 7, the
standard deviation was ±0 1
1
2
Bibliography
Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 460, (1975)
Annual Book of ASTM Standards, Part 31, "Water", Standard D1293-65, p 178 (1976)
Peden, M E and Skowron, L M , Ionic Stability of Precipitation Samples,
Atmospheric Environment, Vol 12, pp 2343-2349, 1978
150 1-3
-------
United States
Environmental Protection
Agency
Environmental Monitoring and
Support Laboratory
Cincinnati OH 45268
Research and Development
pH, Continuous Monitoring
(Electrometric)—Method 150.2
1 Scope and Application
1 1 This method is applicable to the
continuous pH measurement of
drinking surface, and saline waters
domestic and industrial waste waters
2 Summary of Method
2 1 The pH of a sample is determined
electrometncally using a glass
electrode with a reference electrode
or a single combination electrode
3 Sample Handling and
Preservation
3 1 The composition of the water or
waste contacting the measuring
electrode system must be
representative of the total flow from
the water body
4 Interferences
4 1 The glass electrode in general,
is not subject to solution interferences
from color turbidity colloidal matter
oxidants reductants or high salinity
4 2 Sodium error at pH levels
greater than 10 can be reduced or
eliminated by using a low sodium
error electrode
4 3 Manually inspect the conditions
of the electrodes every 30 days for
coating by oily materials or buildup of
lime If oil and grease and/or scale
buildup are not present, this time
interval may be extended
431 Coatings of oil, grease and
very fine solids can impair electrode
response These can usually be
removed by gentle wiping and
detergent washing The use of flow-
through electrode housings which
provide higher flow velocity helps to
prevent the coating action
432 Heavy paniculate matter such
as lime accumulation can be removed
by careful scrubbing or immersion in
dilute (1+9) hydrochloric acid
Continuous monitoring under these
conditions benefits from ultrasonic or
other m-lme continuous cleaning
methods
4 4 Temperature effects on the
eJectrometric measurement of pH
arise from two sources The first is
caused by the change m electrode
output at various temperatures This
interference can be controlled with
instruments having temperature
compensation or by calibrating the
electrode-instrument system at the
temperature of the samples For best
results meters having automatic
temperature compensation should be
calibrated with solutions within 5°C of
the temperature of the stream to be
measured The second source is the
change of pH inherent in the sample
at various temperatures This error is
sample dependent and cannot be
controlled, it should therefore be
noted by reporting both the pH and
temperature at the time of analysis
5 Apparatus
51 pH Monitor - A wide variety of
instruments are commercially
available with various specifications
and optional equipment For
unattended use, the monitor should
be equipped with automatic or fixed
1oO2
Dec 1982
-------
temperature compensation and with a
recorder or alarm function
5 2 Glass electrode - with shielded
cable between electrode and monitor
unless preamplification is used
5.3 Reference electrode - a
reference electrode with a constant
potential and with either a visible
electrolyte or viscous gel fill
NOTE 1 Combination electrodes in-
corporating both measuring and refer-
ence functions are convenient to use
and are available with solid, gel-type fil-
ling materials that require minimal
maintenance
5 4 Temperature sensor - for
automatic compensator covering
general ambient temperature range
5.5 Electrode mounting - to hold
electrodes, may be flow through (for
small flows), pipe mounted or
immersion
6. Reagents
6.1 Primary standard buffer salts are
available from the National Bureau of
Standards and should be used in
situations where extreme accuracy is
required
611 Preparation of reference
solutions from these salts require
some special precautions and
handling1 such as low conductivity
dilution water, drying ovens, and
carbon dioxide free purge gas These
solutions should be replaced at least
once each month
6.2 Secondary buffers may be
prepared from NBS salts or purchased
as a solution from commercial
vendors, Use of these commercially
available solutions, which have been
validated by comparison to NBS
standards, is recommended for
routine operation These buffers may
be retained for at least six months if
kept stoppered
7. Calibration
7.1 Immersion type electrodes -
easily removed from mounting
7.1 1 The electrode should be
calibrated at a minimum of two points
that bracket the expected pH of the
water/waste and are approximately
three pH units or more apart
'National Bureau of Standards Special Publication
260
712 Repeat calibration
adjustments on successive portions of
the two buffer solutions until readings
are within ±0 05 pH units of the buffer
value If calibration problems occur,
see 4 3
713 Because of the wide variety of
instruments available, no detailed
operating instructions are provided
Instead, the analyst should refer to
the particular manufacturer s
instructions
714 Calibration against two buffers
should be carried out at least daily If
the pH of the fluid being measured
fluctuates considerably, the calibration
should be carried out more often
Calibration frequencies may be
relaxed if historical data supports a
longer period between calibration
7 2 Immersion type electrodes -
not easily removed from mounting
727 Collect a grab sample of the
flowing material from a point as close
to the electrode as possible Measure
the pH of this grab sample as quickly
as possible with a laboratory - type pH
meter Adjust the calibration control
of the continuous monitor to the
reading obtained
722 The temperature and condition
of the grab sample must remain
constant until its pH has been
measured by the laboratory pH meter
The temperature of the sample should
be measured and the temperature
compensator of the laboratory pH
meter adjusted
723 The laboratory - type pH meter
should be calibrated prior to use
against two buffers as outlined in 7 1
724 The continuous pH monitoring
system should be initially calibrated
against two buffers as outlined in 7 1
before being placed into service
Recalibration (every 30 days) at two
points is recommended if at all
possible to ensure the measuring
electrode is in working order If this is
not possible, the use of electrode
testing features for a broken or
malfunctioning electrode should be
considered when purchasing the
equipment
725 The indirect calibration should
be carried out at least once a day If
the pH of the fluid being measured
fluctuates considerably, the calibration
should be carried out more often
Calibration frequencies may be
relaxed if historical data support a
longer period between calibration
725 If the electrode can be
removed from the system, but with
difficulty, it should be directly
calibrated as in 7 1 at least once a
month
7 3 Flow-through type electrode -
easily removed from its mounting
7 3 7 Calibrate using buffers as in
7 1 The buffers to be used may be
the piocess stream itself as one
buffer and as a second buffer after
adjustment of pH by addition of an
acid or base This will provide the
larger volumes necessary to calibrate
this type electrode
732 Since the velocity of sample
flow-through a flow through electrode
can produce an offset error in pH
reading, the user must have data on
hand to show that the offset is known
and compensation has been
accomplished
7 4 Flow-through type electrode -
not easily removed from its mounting
741 Calibrate as in 7 2
742 Quality control data must be
on hand to show the user is aware of
possible sample flow velocity effects
8 Procedure
8 1 Calibrate the monitor and
electrode system as outlined in
Section 7
8 2 Follow the manufacturer's
recommendation for operation and
installation of the system
83 In wastewaters, the electrode
may require periodic cleaning After
manual cleaning, the electrode should
be calibrated as in 7 1 or 7 2 before
returning to service
8 4 The electrode must be placed so
that the water or waste flowing past
the electrode is representative of the
system
9 Calculations
91 pH meters read directly in pH
units Reports pH to the nearest 0 1
unit and temperature to the nearest
°C
10 Precision and Accuracy
101 Because of the wide variability
of equipment and conditions and the
changeable character of the pH of
many process waters and wastes, the
precision of this method is probably
less than that of Method 150 1,
however, a precision of 0 1 pH unit
Dec 1982
ISO 2-2
-------
be attamatAe )n the range of
pH 6 0 to 8 0 Accuracy data for
continuous monitoring equipment
are not available at this time
Bibliography
1 Annual Book of ASTM
'Standards Part 31, Water
Standard 1293-78, Method D, p 226
(1981)
75023 Dec 1982
-------
RESIDUE, FILTERABLE
Method 160.1 (Gravimetric, Dried at 180°C)
STORE! NO. 70300
1 Scope and Application
1 1 This method is applicable to drinking, surface, and saline waters, domestic and industrial
wastes
1 2 The practical range of the determination is 10 mg/1 to 20,000 mg/1
2 Summary of Method
21 A well-mixed sample is filtered through a standard glass fiber filter The filtrate is
evaporated and dried to constant weight at 180°C
22 If Residue, Non-Filterable is being determined, the filtrate from that method may be
used for Residue, Filterable
3 Definitions
3 1 Filterable residue is defined as those solids capable of passing through a glass fiber filter
and dried to constant weight at 180°C
4 Sample Handling and Preservation
4 1 Preservation of the sample is not practical, analysis should begin as soon as possible
Refrigeration or icing to 4°C, to minimize microbiological decomposition of solids, is
recommended
5 Interferences
5 1 Highly mineralized waters containing significant concentrations of calcium, magnesium,
chloride and/or sulfate may be hygroscopic and will require prolonged drying,
desiccation and rapid weighing
5 2 Samples containing high concentrations of bicarbonate will require careful and possibly
prolonged drying at 180°C to insure that all the bicarbonate is converted to carbonate
5 3 Too much residue in the evaporating dish will crust over and entrap water that will not
be driven off during drying Total residue should be limited to about 200 mg
6 Apparatus
6 1 Glass fiber filter discs, 4 7 cm or 2 1 cm, without organic binder, Reeve Angel type 934-
AH, Gelman type A/E, or equivalent
6 2 Filter holder, membrane filter funnel or Gooch crucible adapter
6 3 Suction flask, 500 ml
6 4 Gooch crucibles, 25 ml (if 2 1 cm filter is used)
6 5 Evaporating dishes, porcelain, 100 ml volume (Vycor or platinum dishes may be
substituted)
6 6 Steam bath
67 Drying oven, 180°C ±2°C
6 8 Desiccator
Approved for NPDES
Issued 1971
160 1-1
-------
6 9 Analytical balance, capable of weighing to 0 1 mg
7 Procedure
7 1 Preparation of glass fiber filter disc Place the disc on the membrane filter apparatus or
insert into bottom of a suitable Gooch crucible While vacuum is applied, wash the disc
with three successive 20 ml volumes of distilled water Remove all traces of water by
continuing to apply vacuum after water has passed through Discard washings
7 2 Preparation of evaporating dishes If Volatile Residue is also to be measured heat the
clean dish to 550 ±50°C for one hour in a muffle furnace If only Filterable Residue is to
be measured heat the clean dish to 180 ±2°C for one hour Cool in desiccator and store
until needed Weigh immediately before use
7 3 Assemble the filtering apparatus and begin suction Shake the sample vigorously and
rapidly transfer 100 ml to the funnel by means of a 100 ml graduated cylinder If total
filterable residue is low, a larger volume may be filtered
7 4 Filter the sample through the glass fiber filter, rmse with three 10 ml portions of distilled
water and continue to apply vacuum for about 3 minutes after filtration is complete to
remove as much water as possible
7 5 Transfer 100 ml (or a larger volume) of the filtrate to a weighed evaporating dish and
evaporate to dryness on a steam bath
7 6 Dry the evaporated sample for at least one hour at 180 ±2°C Cool in a desiccator and
weigh Repeat the drying cycle until a constant weight is obtained or until weight loss is
less than 0 5 mg
8. Calculation
8 1 Calculate filterable residue as follows
„, ,. , ., (A - B)x 1,000
Filterable residue, mg/1 =
where
A = weight of dried residue + dish in mg
B = weight of dish in mg
C = volume of sample used in ml
9 Precision and Accuracy
9.1 Precision and accuracy are not available at this time
Bibliography
1. Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 92, Method
208B,(1975)
160 1-2
-------
RESIDUE, NON-FILTERABLE
Method 160.2 (Gravimetric, Dried at 103-105°C)
STORET NO. 00530
Scope and Application
1 1 This method is applicable to drinking, surface, and saline waters, domestic and industrial
wastes
1 2 The practical range of the determination is 4 mg/1 to 20,000 mg/1
Summary of Method
21 A well-mixed sample is filtered through a glass fiber filter, and the residue retained on the
filter is dried to constant weight at 103-105°C
2 2 The filtrate from this method may be used for Residue, Filterable
Definitions
3 1 Residue, non-filterable, is defined as those solids which are retained by a glass fiber filter
and dried to constant weight at 103-105°C
Sample Handling and Preservation
4 1 Non-representative particulates such as leaves, sticks, fish, and lumps of fecal matter
should be excluded from the sample if it is determined that their inclusion is not desired
in the final result
4 2 Preservation of the sample is not practical, analysis should begin as soon as possible
Refrigeration or icing to 4°C, to minimize microbiological decomposition of solids, is
recommended
Interferences
5 1 Filtration apparatus, filter material, pre-washing, post-washing, and drying temperature
are specified because these variables have been shown to affect the results
5 2 Samples high in Filterable Residue (dissolved solids), such as saline waters, brines and
some wastes, may be subject to a positive interference Care must be taken in selecting the
filtering apparatus so that washing of the filter and any dissolved solids in the filter (7 5)
minimizes this potential interference
Apparatus
6 1 Glass fiber filter discs, without organic binder, such as Millipore AP-40, Reeves Angel
934-AH, Gelman type A/E, or equivalent
NOTE: Because of the physical nature of glass fiber filters, the absolute pore size cannot
be controlled or measured Terms such as "pore size", collection efficiencies and effective
retention are used to define this property in glass fiber filters Values for these parameters
vary for the filters listed above
6 2 Filter support filtering apparatus with reservoir and a coarse (40-60 microns) fritted
disc as a filter support
Approved for NPDES
Issued 1971
160 2-1
-------
NOTE: Many funnel designs are available m glass or porcelain Some of the most
common are Hirsch or Buchner funnels, membrane filter holders and Gooch crucibles
All are available with coarse fritted disc
6 3 Suction flask
6 4 Drying oven, 103-105°C
6 5 Desiccator
6 6 Analytical balance, capable of weighing to 0 1 mg
Procedure
7.1 Preparation of glass fiber filter disc Place the glass fiber filter on the membrane filter
apparatus or insert into bottom of a suitable Gooch crucible with wrinkled surface up
While vacuum is applied, wash the disc with three successive 20 ml volumes of distilled
water Remove all traces of water by continuing to apply vacuum after water has passed
through Remove filter from membrane filter apparatus or both crucible and filter if
Gooch crucible is used, and dry in an oven at 103-105°C for one hour Remove to
desiccator and store until needed Repeat the drying cycle until a constant weight is
obtained (weight loss is less than 0 5 mg) Weigh immediately before use After weighing,
handle the filter or crucible/filter with forceps or tongs only
7 2 Selection of Sample Volume
For a 4.7 cm diameter filter, filter 100 ml of sample If weight of captured residue is less
than 1 0 mg, the sample volume must be increased to provide at least 1 0 mg of residue If
other filter diameters are used, start with a sample volume equal to 7 ml/cm2 of filter area
and collect at least a weight of residue proportional to the 1 0 mg stated above
NOTE: If during filtration of this initial volume the filtration rate drops rapidly, or if
filtration time exceeds 5 to 10 minutes, the following scheme is recommended Use an
unweighed glass fiber filter of choice affixed in the filter assembly Add a known volume
of sample to the filter funnel and record the time elapsed after selected volumes have
passed through the filter Twenty-five ml increments for timing are suggested Continue
to record the time and volume increments until fitration rate drops rapidly Add
additional sample if the filter funnel volume is inadequate to reach a reduced rate Plot
the observed tune versus volume filtered Select the proper filtration volume as that just
short of the time a significant change in filtration rate occurred
7 3 Assemble the filtering apparatus and begin suction Wet the filter with a small volume of
distilled water to seat it against the fritted support
7.4 Shake the sample vigorously and quantitatively transfer the predetermined sample
volume selected in 7 2 to the filter using a graduated cylinder Remove all traces of water
by continuing to apply vacuum after sample has passed through
7 5 With suction on, wash the graduated cylinder, filter, non-filterable residue and filter
funnel wall with three portions of distilled water allowing complete drainage between
washing Remove all traces of water by continuing to apply vacuum after water has
passed through
NOTE: Total volume of wash water used should equal approximately 2 ml per cm2 For a
4 7 cm filter the total volume is 30 ml
160 2-2
-------
7 6 Carefully remove the filter from the filter support Alternatively, remove crucible and
filter from crucible adapter Dry at least one hour at 103-105°C Cool in a desiccator and
weigh Repeat the drying cycle until a constant weight is obtained (weight loss is less than
05mg)
Calculations
8 1 Calculate non-filterable residue as follows
TVT PI. ui A n (A - B)X 1,000
Non-filterable residue, mg/1 = * —'•—
where
A — weight of filter (or filter and crucible) + residue in mg
B = weight of filter (or filter and crucible) in mg
C = ml of sample filtered
Precision and Accuracy
9 1 Precision data are not available at this time
9 2 Accuracy data on actual samples cannot be obtained
Bibliography
NCASI TechmcarBulletm No 291, March 1977 National Council of the Paper Industry for
Air and Stream Improvement, Inc , 260 Madison Ave , NY
160 2-3
-------
RESIDUE, TOTAL
Method 160.3 (Gravimetric, Dried at 103-105°C)
STORET NO. 00500
Scope and Application
1 1 This method is applicable to drinking, surface, and saline waters, domestic and industrial
wastes
1 2 The practical range of the determination is from 10 mg/1 to 20,000 mg/1
Summary of Method
21 A well mixed aliquot of the sample is quantitatively transferred to a pre-weighed
evaporating dish and evaporated to dryness at 103-105°C
Definitions
3 1 Total Residue is defined as the sum of the homogenous suspended and dissolved
materials m a sample
Sample Handling and Preservation
4 1 Preservation of the sample is not practical, analysis should begin as soon as possible
Refrigeration or icing to 4°C, to minimize microbiological decomposition of solids, is
recommended
Interferences
5 1 Non-representative particulates such as leaves, sticks, fish and lumps of fecal matter
should be excluded from the sample if it is determined that their inclusion is not desired
in the final result
5 2 Floating oil and grease, if present, should be included m the sample and dispersed by a
blender device before ahquotmg
Apparatus
6 1 Evaporating dishes, porcelain, 90 mm, 100 ml capacity (Vycor or platinum dishes may
be substituted and smaller size dishes may be used if required )
Procedure
7 1 Heat the clean evaporating dish to 103-105°C for one hour, if Volatile Residue is to be
measured, heat at 550 ±50°C for one hour in a muffle furnace Cool, desiccate, weigh and
store in desiccator until ready for use
7 2 Transfer a measured aliquot of sample to the pre-weighed dish and evaporate to dryness
on a steam bath or in a drying oven
721 Choose an aliquot of sample sufficient to contain a residue of at least 25 mg To
obtain a weighable residue, successive aliquots of sample may be added to the same
dish
722 If evaporation is performed m a drying oven, the temperature should be lowered to
approximately 98°C to prevent boiling and splattering of the sample
Approved for NPDES
Issued 1971
160 3-1
-------
7 3 Dry the evaporated sample for at least 1 hour at 103-105°C Cool in a desiccator and
weigh Repeat the cycle of drying at 103-105°C, cooling, desiccating and weighing until a
constant weight is obtained or until loss of weight is less than 4% of the previous weight,
or 0 5 mg, whichever is less
8 Calculation
8.1 Calculate total residue as follows
Total rescue,
where
A = weight of sample + dish in mg
B = weight of dish in mg
C = volume of sample in ml
9. Precision and Accuracy
9.1 Precision and accuracy data are not available at this time
Bibliography
1. Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 91, Method
208A, (1975)
160 3-2
-------
RESIDUE, VOLATILE
Method 160.4 (Gravimetric, Ignition at 550°C)
STORET NO. Total 00505
Non-Filterable 00535
Filterable 00520
Scope and Application
1 1 This method determines the weight of solid material combustible at 550°C
1 2 The test is useful in obtaining a rough approximation of the amount of organic matter
present in the solid fraction of sewage, activated sludge, industrial wastes, or bottom
sediments
Summary of Method
2 1 The residue obtained from the determination of total, filterable or non-filterable residue
is ignited at 550°C in a muffle furnace The loss of weight on ignition is reported as mg/1
volatile residue
Comments
3 1 The test is subject to many errors due to loss of water of crystallization, loss of volatile
organic matter prior to combustion, incomplete oxidation of certain complex organics,
and decomposition of mineral salts during combustion
3 2 The results should not be considered an accurate measure of organic carbon in the
sample, but may be useful in the control of plant operations
3 3 The principal source of error in the determination is failure to obtain a representative
sample
Sample Handling and Preservation
4 1 Preservation of the sample is not practical, analysis should begin as soon as possible
Refrigeration or icing to 4°C, to minimize microbiological decompostion of solids is
recommended
Precision and Accuracy
5 1 A collaborative study involving three laboratories examining four samples by means of
ten replicates showed a standard deviation of +11 mg/1 at 170 mg/1 volatile residue
concentration
Reference
6 1 The procedure to be used for this determination is found in
Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 95,
Method 208E, (1975)
Approved for NPDES
Issued 1971
160 4-1
-------
SETTLEABLE MATTER
Method 160.5 (Volumetric, Imhoff Cone)
STORET NO. 50086
Scope and Application
1 1 This method is applicable to surface and saline waters, domestic and industrial wastes
1 2 The practical lower limit of the determination is about 0 2 ml/l/hr
Summary of Method
2 1 Settleable matter is measured volumetncally with an Imhoff cone
Comments
3 1 For some samples, a separation of settleable and floating materials will occur, in such
cases the floating materials are not measured
32 Many treatment plants, especially plants equipped to perform gravimetric
measurements, determine residue non-filterable (suspended solids), m preference to
settleable matter, to insure that floating matter is included in the analysis
Precision and Accuracy
4 1 Data on this determination are not available at this time
References
5 1 The procedure to be used for this determination is found in
Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 95,
Method 208F, Procedure 3a (1975)
Approved for NPDES
Issued 1974
160 5-1
-------
TEMPERATURE
Method 170.1 (Thermometric)
STORET NO. 00010
1 Scope and Application
1 1 This method is applicable to drinking, surface, and saline waters, domestic and industrial
wastes
2 Summary of Method
2 1 Temperatuf e measurements may be made with any good grade of mercury-filled or dial
type centigrade thermometer, or a thermistor
3 Comments
3 1 Measurement device should be routinely checked against a precision thermometer
certified by the National Bureau of Standards
4 Precision and Accuracy
4 1 Precision and accuracy for this method have not been determined
5 Reference
5 1 The procedure to be used for this determination is found in
Standard Methods for the Examination of Water and Wastewater, 14th Edition D 125
Method 212 (1975)
Approved for NPDES
Issued 1971
170 1-1
-------
TURBIDITY
Method 180.1 (Nephelometric)
STORET NO. 00076
1 Scope and Application
1 1 This method is applicable to drinking, surface, and saline waters in the range of turbidity
from 0 to 40 nephelometnc turbidity units (NTU) Higher values may be obtained with
dilution of the sample
NOTE 1: NTU's are considered comparable to the previously reported Formazm
Turbidity Units (FTU) and Jackson Turbidity Units (JTU)
2 Summary of Method
2.1 The method is based upon a comparison of the intensity of light scattered by the sample
under defined conditions with the intensity of light scattered by a standard reference
suspension The higher the intensity of scattered light, the higher the turbidity Readings,
in NTU's, are made in a nephelometer designed according to specifications outlined in
Apparatus A standard suspension of Formazm, prepared under closely defined
conditions, is used to calibrate the instrument
2 1 1 Formazm polymer is used as the turbidity reference suspension for water because it
is more reproducible than other types of standards previously used for turbidity
standards
2 1 2 A commercially available polymer standard is also approved for use for the
National Interim Primary Drinking Water Regulations This standard is identified
as AMCO-AEPA-1 available from Amco Standard International, Inc
3 Sample Handling and Preservation
3 1 Preservation of the sample is not practical, analysis should begin as soon as possible
Refrigeration or icing to 4°C, to minimize microbiological decomposition of solids, is
recommended
4 Interferences
4 1 The presence of floating debris and coarse sediments which settle out rapidly will give
low readings Finely divided air bubbles will affect the results in a positive manner
4 2 The presence of true color, that is the color of water which is due to dissolved substances
which absorb light, will cause turbidities to be low, although this effect is generally not
significant with finished waters
5 Apparatus
5 1 The turbidimeter shall consist of a nephelometer with light source for illuminating the
sample and one or more photo-electric detectors with a readout device to indicate the
intensity of light scattered at right angles to the path of the incident light The
turbidimeter should be so designed that little stray light reaches the detector in the
Approved for NPDES and SDWA
Issued 1971
Editorial revision 1974
Editorial revision 1978
180 1-1
-------
absence of turbidity and should be free from significant drift after a short warm-up
period
5 2 The sensitivity of the instrument should permit detection of a turbidity difference of 0 02
unit or less in waters having turbidities less than 1 unit The instrument should measure
from 0 to 40 units turbidity Several ranges will be necessary to obtain both adequate
coverage and sufficient sensitivity for low turbidities
5 3 The sample tubes to be used with the available instrument must be of clear, colorless
glass They should be kept scrupulously clean, both inside and out, and discarded when
they become scratched or etched They must not be handled at all where the light strikes
them, but should be provided with sufficient extra length, or with a protective case, so
that they may be handled
5 4 Differences in physical design of turbidimeters will cause differences in measured values
for turbidity even though the same suspension is used for calibration To minimize such
differences, the following design criteria should be observed
541 Light source Tungsten lamp operated at a color temperature between
2200-3000°K
542 Distance traversed by incident light and scattered light within the sample tube
Total not to exceed 10 cm
543 Detector Centered at 90° to the incident light path and not to exceed ±30° from
90° The Detector, and filter system if used, shall have a spectral peak response
between 400 and 600nm
5 5 The Hach Turbidimeter, Model 2100 and 2100 A, is in wide use and has been found to be
reliable, however, other instruments meeting the above design criteria are acceptable
Reagents
6.1 Turbidity-free water Pass distilled water through a 0 45u pore size membrane filter if
such filtered water shows a lower turbidity than the distilled water
6 2 Stock formazin turbidity suspension
Solution 1 Dissolve 1 00 g hydrazine sulfate, (NH2)2«H2SO4, in distilled water and dilute
to 100 ml in a volumetric flask
Solution 2 Dissolve 10 00 g hexamethylenetetramme in distilled water and dilute to 100
ml in a volumetric flask
In a 100 ml volumetric flask, mix 5 0 ml Solution 1 with 5 0 ml Solution 2 Allow to stand
24 hours at 25 ±3°C, then dilute to the mark and mix
6 3 Standard formazin turbidity suspension Dilute 10 00 ml stock turbidity suspension to
100 ml with turbidity-free water The turbidity of this suspension is defined as 40 units
Dilute portions of the standard turbidity suspension with turbidity-free water as
required
6 3 1 A new stock turbidity suspension should be prepared each month The standard
turbidity suspension and dilute turbidity standards should be prepared weekly by
dilution of the stock turbidity suspension
6 4 The AMCO-AEPA-1 standard as supplied requires no preparation or dilution prior to
use
180 1-2
-------
Procedure
7 1 Turbidimeter calibration The manufacturer's operating instructions should be followed
Measure standards on the turbidimeter covering the range of interest If the instrument is
already calibrated in standard turbidity units, this procedure will check the accuracy of
the calibration scales At least one standard should be run m each instrument range to be
used Some instruments permit adjustments of sensitivity so that scale values will
correspond to turbidities Reliance on a manufacturer's solid scattering standard for
setting overall instrument sensitivity for all ranges is not an acceptable practice unless the
turbidimeter has been shown to be free of drift on all ranges If a pre-cahbrated scale is
not supplied, then calibration curves should be prepared for each range of the
instrument
7 2 Turbidities less than 40 units Shake the sample to thoroughly disperse the solids Wait
until air bubbles disappear then pour the sample into the turbidimeter tube Read the
turbidity directly from the instrument scale or from the appropriate calibration curve
7 3 Turbidities exceeding 40 units Dilute the sample with one or more volumes of turbidity-
free water until the turbidity falls below 40 units The turbidity of the original sample is
then computed from the turbidity of the diluted sample and the dilution factor For
example, if 5 volumes of turbidity-free water were added to 1 volume of sample, and the
diluted sample showed a turbidity of 30 units, then the turbidity of the original sample
was 180 units
7 3 1 The Hach Turbidimeters, Models 2100 and 2100A, are equipped with 5 separate
scales 0-0 2, 0-1 0, 0-100, and 0-1000 NTU The upper scales are to be used only
as indicators of required dilution volumes to reduce readings to less than 40 NTU
NOTE 2: Comparative work performed in the MDQAR Laboratory indicates a
progressive error on sample turbidities in excess of 40 units
Calculation
8 1 Multiply sample readings by appropriate dilution to obtain final reading
8 2 Report results as follows
Record to Nearest
00-10 005
1-10 01
10-40 ,
40 - 100 5
100 - 400 10
400 - 1000 50
>1Q00 100
Precision and Accuracy
91 In a single laboratory (EMSL), using surface water samples at levels of 26,41, 75 and 180
NTU, the standard deviations were ±0 60, ±0 94, ±12 and ±4 7 units, respectively
9 2 Accuracy data are not available at this time
180 1-3
-------
Bibliography
1 Annual Book of ASTM Standards, Part 31, "Water", Standard D1889-71, p 223 (1976)
2. Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 132,
Method 214A, (1975)
180 1-4
-------
METALS
(Atomic Absorption Methods)
1 Scope and Application
1 1 Metals in solution may be readily determined by atomic absorption spectroscopy The
method is simple, rapid, and applicable to a large number of metals in drinking, surface,
and saline waters, and domestic and industrial wastes While drinking waters free of
particulate matter may be analyzed directly, domestic and industrial wastes require
processing to solubihze suspended material Sludges, sediments and other solid type
samples may also be analyzed after proper pretreatment
1 2 Detection limits, sensitivity and optimum ranges of the metals will vary with the various
makes and models of satisfactory atomic absorption spectrophotometers The data
shown in Table 1, however, provide some indication of the actual concentration ranges
measurable by direct aspiration and using furnace techniques In the majority of
instances the concentration range shown in the table by direct aspiration may be
extended much lower with scale expansion and conversely extended upwards by using a
less sensitive wavelength or by rotating the burner head Detection limits by direct
aspiration may also be extended through concentration of the sample and/or through
solvent extraction techniques Lower concentrations may also be determined using the
furnace techniques The concentration ranges given in Table 1 are somewhat dependent
on equipment such as the type of spectrophotometer and furnace accessory, the energy
source and the degree of electrical expansion of the output signal When using furnace
techniques, however, the analyst should be cautioned as to possible chemical reactions
occurring at elevated temperatures which may result in either suppression or
enhancement of the analysis element To insure valid data with furnace techniques, the
analyst must examine each matrix for interference effects (see 521) and if detected, treat
accordingly using either successive dilution, matrix modification or method of standard
additions (see 8 5)
1 3 Where direct aspiration atomic absorption techniques do not provide adequate
sensitivity, m addition to the furnace procedure, reference is made to specialized
procedures such as the gaseous hydride method for arsenic and selenium, the cold vapor
technique for mercury, and the chelation-extraction procedure for selected metals
Reference to approved colonmetnc methods is also made
1 4 Atomic absorption procedures are provided as the methods of choice, however, other
instrumental methods have also been shown to be capable of producing precise and
accurate analytical data These instrumental techniques include emission spectroscopy,
X-ray fluorescence, spark source mass spectroscopy, and anodic stripping to name but a
few The analyst should be cautioned that these methods are highly specialized
techniques requiring a high degree of skill to interpret results and obtain valid data
Approved for NPDES and SDWA
Issued 1969
Editorial revision 1974 and 1978
METALS-1
-------
These above mentioned techniques are presently considered as alternate test procedures
and approval must be obtained prior to their use
2. Summary of Method
2.1 In direct aspiration atomic absorption spectroscopy a sample is aspirated and atomized
in a flame A light beam from a hollow cathode lamp whose cathode is made of the
element to be determined is directed through the flame into a monochromator, and onto
a detector that measures the amount of light absorbed Absorption depends upon the
presence of free unexcited ground state atoms m the flame Since the wavelength of the
light beam is characteristic of only the metal being determined, the light energy absorbed
by the flame is a measure of the concentration of that metal in the sample This principle
is the basis of atomic absorption spectroscopy
2.2 Although methods have been reported for the analysis of solids by atomic absorption
spectroscopy (Spectrochim Acta, 24B 53, 1969) the technique generally is limited to
metals in solution or solubihzed through some form of sample processing
221 Preliminary treatment of wastewater and/or industrial effluents is usually
necessary because of the complexity and variability of the sample matrix
Suspended material must be subjected to a solubihzation process before analysis
This process may vary because of the metals to be determined and the nature of the
sample being analyzed When the breakdown of organic material is necessitated,
the process should include a wet digestion with nitric acid
2 2 2 In those instances where complete characterization of a sample is desired, the
suspended material must be analyzed separately This may be accomplished by
filtration and acid digestion of the suspended material Metallic constituents in this
acid digest are subsequently determined and the sum of the dissolved plus
suspended concentrations will then provide the total concentrations present The
sample should be filtered as soon as possible after collection and the filtrate
acidified immediately
223 The total sample may also be treated with acid without prior filtration to measure
what may be termed "total recoverable" concentrations
2 3 When using the furnace technique in conjunction with an atomic absorption
spectrophotometer, a representative aliquot of a sample is placed in the graphite tube in
the furnace, evaporated to dryness, charred, and atomized As a greater percentage of
available analyte atoms are vaporized and dissociated for absorption in the tube than the
flame, the use of small sample volumes or detection of low concentrations of elements is
possible The principle is essentially the same as with direct aspiration atomic absorption
except a furnace, rather than a flame, is used to atomize the sample Radiation from a
given excited element is passed through the vapor containing ground state atoms of that
element The intensity of the transmitted radiation decreases in proportion to the amount
of the ground state element in the vapor
METALS-2
-------
TABLE 1
Atomic Absorption Concentration Ranges0'
Direct Aspiration Furnace Procedure'4 »S)
Metal
Aluminum
Antimony
Arsenic0'
Banum(p)
Beryllium
Cadmium
Calcium
Chromium
Cobalt
Copper
Gold
Indmm(p)
Iron
Lead
Magnesium
Manganese
Mercury™
Molybdenum(p)
Nickel(p)
Osmium
Palladmm(p)
Platmum(p)
Potassium
Rhemum(p)
Rhodium(p)
Ruthenium
Selenium"'
Silver
Sodium
Thallium
Tin
Titanium (p)
Vanadium (p)
Zinc
Detection
Limit
mg/1
01
02
0002
01
0005
0005
001
005
005
002
01
3
003
01
0001
001
00002
01
004
03
01
02
001
5
005
02
0002
001
0002
01
08
04
02
0005
Optimum
Concentration
Sensitivity
mg/1
1
05
-
04
0025
0025
008
025
02
01
025
8
012
05
0007
005
-
04
015
1
025
2
004
15
03
05
-
006
0015
05
4
2
08
002
Range
mg/1
5
1
0002 -
1
005
005
02
05
05
02
05
20
03
1
002
01
00002 -
1
03
2
05
5
01
50
1
1
0002 -
01
003
1
10
5
2
005
50
40
002
20
2
2
7
10
5
5
20
500
5
20
0,5
3
001
40
5
100
15
75
2
1000
30
50
002
4
1
20
300
100
100
1
Detection
Limit
ug/1
3
3
1
2
02
01
1
1
1
1
30
1
1
02
1
1
20
5
20
200
5
20
2
02
1
5
10
4
005
Optimum
Concentration
Range
ug/1
20
20
5
10
1
05 -
5
5
5
5
100
5
5
1 _
3
5
50
20
100
500
20
100
5 _
1
5
20
50
10
02 -
200
300
100
200
30
10
100
100
100
100
1500
100
100
30
60
50
500
400
2000
5000
400
2000
100
25
100
300
500
200
4
(1)
(2)
(3)
(4)
(5)
The concentrations shown are not contrived values and should be obtainable with any satisfactory atomic absorption
spectrophotometer
Gaseous hydride method
Cold vapor technique
For furnace sensitivity values consult instrument operating manual
The listed furnace values are those expected when using a 20 u\ injection and normal gas flow except in the case of arsenic and
selenium where gas interrupt is used The symbol (p) indicates the use of pyrolytic graphite with the furnace procedure
METALS-3
-------
The metal atoms to be measured are placed in the beam of radiation by increasing the temperature of
the furnace thereby causing the injected specimen to be volatilized A monochromator isolates the
characteristic radiation from the hollow cathode lamp and a photosensitive device measures the
attenuated transmitted radiation
3 Definition of Terms
3 1 Optimum Concentration Range A range, defined by limits expressed in concentration,
below which scale expansion must be used and above which curve correction should be
considered This range will vary with the sensitivity of the instrument and the operating
condition employed
3 2 Sensitivity The concentration in milligrams of metal per liter that produces an
absorption of 1 %
3 3 Detection Limit Detection limits can be expressed as either an instrumental or method
parameter The limiting factor of the former using acid water standards would be the
signal to noise ratio and degree of scale expansion used, while the latter would be more
affected by the sample matrix and preparation procedure used The Scientific Apparatus
Makers Association (SAMA) has approved the following definition for detection limit
that concentration of an element which would yield an absorbance equal to twice the
standard deviation of a series of measurements of a solution, the concentraton of which is
distinctly detectable above, but close to blank absorbance measurement The detection
limit values listed in Table I and on the individual analysis sheets are to be considered
minimum working limits achievable with the procedures given in this manual These
values may differ from the optimum detection limit reported by the various instrument
manufacturers
34 Dissolved Metals Those constituents (metals) which will pass through a 045 u
membrane filter
3 5 Suspended Metals Those constituents (metals) which are retained by a 0 45 u membrane
filter
3 6 Total Metals The concentration of metals determined on an unfiltered sample following
vigorous digestion (Section 4 1 3), or the sum of the concentrations of metals in both the
dissolved and suspended fractions
3 7 Total Recoverable Metals The concentration of metals in an unfiltered sample following
treatment with hot dilute mineral acid (Section 414)
4 Sample Handling and Preservation
4.1 For the determination of trace metals, contamination and loss are of prime concern Dust
in the laboratory environment, impurities in reagents and impurities on laboratory
apparatus which the sample contacts are all sources of potential contamination For
liquid samples, containers can introduce either positive or negative errors in the
measurement of trace metals by (a) contributing contaminants through leaching or
surface desorption and (b) by depleting concentrations through adsorption Thus the
collection and treatment of the sample prior to analysis requires particular attention The
sample bottle whether borosihcate glass, polyethylene polypropylene or Teflon should
be thoroughly washed with detergent and tap water, rinsed with 1 1 nitric acid, tap
METALS-4
-------
water, 1 1 hydrochloric acid, tap water and finally deionized distilled water in that
order
NOTE 1: Chromic acid may be useful to remove organic deposits from glassware,
however, the analyst should be cautioned that the glassware must be thoroughly rinsed
with water to remove the last traces of chromium This is especially important if
chromium is to be included in the analytical scheme A commercial product—
NOCHROMIX—available from Godax Laboratories, 6 Vanck St New York, N Y
10013, may be used in place of chromic acid [Chromic acid should not be used with
plastic bottles ]
NOTE 2 If it can be documented through an active analytical quality control program
using spiked samples, reagent and sample blanks, that certain steps in the cleaning
procedure are not required for routine samples, those steps may be eliminated from the
procedure
Before collection of the sample a decision must be made as to the type of data desired, i e,
dissolved, suspended, total or total recoverable For container preference, maximum
holding time and sample preservation at time of collection see Table 1 in the front part of
this manual Drinking water samples containing suspended and setteable material should
be prepared using the total recoverable metal procedure (section 4 1 4)
4 1 1 For the determination of dissolved constituents the sample must be filtered
through a 0 45 u membrane filter as soon as practical after collection (Glass or
plastic filtering apparatus using plain, non-grid marked, membrane filters are
recommended to avoid possible contamination ) Use the first 50-100 ml to rinse
the filter flask Discard this portion and collect the required volume of filtrate
Acidify the filtrate with 1 1 redistilled HNO3 to a pH of <2 Normally, 3 ml of
(1 1) acid per liter should be sufficient to preserve the sample (See Note 3) If
hexavalent chromium is to be included in the analytical scheme, a portion of the
filtrate should be transferred before acidification to a separate container and
analyzed as soon as possible using Method 2184 Analyses performed on a sample
so treated shall be reported as "dissolved" concentrations
NOTE 3 If a precipitate is formed upon acidification, the filtrate should be digested
using 413 Also, it has been suggested (International Biological Program, Symposium
on Analytical Methods, Amsterdam, Oct 1966) that additional acid, as much as 25 ml of
cone HCl/liter, may be required to stabilize certain types of highly buffered samples if
they are to be stored for any length of time Therefore, special precautions should be
observed for preservation and storage of unusual samples intended for metal analysis
412 For the determination of suspended metals a representative volume of unpreserved
sample must be filtered through a 0 45 u membrane filter When considerable
suspended material is present, as little as 100 ml of a well mixed sample is filtered
Record the volume filtered and transfer the membrane filter containing the
insoluble material to a 250 ml Griffin beaker and add 3 ml cone redistilled HNO3
Cover the beaker with a watch glass and heat gently The warm acid will soon
dissolve the membrane Increase the temperature of the hot plate and digest the
material When the acid has nearly evaporated, cool the beaker and watch glass
and add another 3 ml of cone redistilled HNO3 Cover and continue heating until
METALS-5
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the digestion is complete, generally indicated by a light colored digestate
Evaporate to near dryness (DO NOT BAKE), add 5 ml distilled HC1 (1 1) and
warm the beaker gently to dissolve any soluble material (If the sample is to be
analyzed by the furnace procedure, 1 ml of 1 1 distilled HNO3 per 100 ml dilution
should be substituted for the distilled 1 1 HC1) Wash down the watch glass and
beaker walls with deiomzed distilled water and filter the sample to remove silicates
and other insoluble material that could clog the atomizer Adjust the volume to
some predetermined value based on the expected concentrations of metals present
This volume will vary depending on the metal to be determined The sample is now
ready for analysis Concentrations so determined shall be reported as "suspended"
(See Note 4)
NOTE 4: Certain metals such as antimony arsenic, gold, indium, mercury,
osmium, palladium, platimum, rhenium, rhodium, ruthenium, selenium, silver,
thallium, tin and titanium require modification of the digestion procedure and the
individual sheets for these metals should be consulted
413 For the determination of total metals the sample is acidified with 1 1 redistilled
HNO3 to a pH of less than 2 at the time of collection The sample is not filtered
before processing Choose a volume of sample appropriate for the expected level of
metals If much suspended material is present, as little as 50-100 ml of well mixed
sample will most probably be sufficient (The sample volume required may also
vary proportionally with the number of metals to be determined )
Transfer a representative aliquot of the well mixed sample to a Griffin beaker and
add 3 ml of cone redistilled HNO3 Place the beaker on a hot plate and evaporate
to near dryness cautiously, making certain that the sample does not boil (DO NOT
BAKE ) Cool the beaker and add another 3 ml portion of cone redistilled HNO3
Cover the beaker with a watch glass and return to the hot plate Increase the
temperature of the hot plate so that a gentle reflux action occurs Continue heating,
adding additional acid as necessary, until the digestion is complete (generally
indicated when the digestate is light in color or does not change in appearance with
continued refluxmg) Again, evaporate to near dryness and cool the beaker Add a
small quantity of redistilled 1 1 HC1 (5 ml/100 ml of final solution) and warm the
beaker to dissolve any precipitate or residue resulting from evaporation (If the
sample is to be analyzed by the furnace procedure, substitute distilled HNO3 for 1 1
HC1 so that the final dilution contains 0 5% (v/v) HNO3) Wash down the beaker
walls and watch glass with distilled water and filter the sample to remove silicates
and other insoluble material that could clog the atomizer Adjust the volume to
some predetermined value based on the expected metal concentrations The sample
is now ready for analysis Concentrations so determined shall be reported as
"total" (see Note 4)
4 1.4 To determine total recoverable metals, acidify the entire sample at the time of
collection with cone redistilled HNO3, 5 ml/1 At the time of analysis a 100 ml
aliquot of well mixed sample is transferred to a beaker or flask Five ml of distilled
HC1 (1 1) is added and the sample heated on a steam bath or hot plate until the
METALS-6
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volume has been reduced to 15-20 ml making certain the samples do not boil (If
the sample is being prepared for furnace analysis, the same process should be
followed except HC1 should be omitted ) After this treatment the sample is filtered
to remove silicates and other insoluble material that could clog the atomizer and
the volume adjusted to 100 ml The sample is then ready for analysis
Concentrations so determined shall be reported as "total" (See Notes 4, 5, and 6 )
NOTE 5: The analyst should be cautioned that this digestion procedure may not be
sufficiently vigorous to destroy certain metal complexes if a colonmetnc procedure
is to be employed for the final determination When this is suspect, the more
vigorous digestion given in 4 1 3 should be followed
NOTE 6: For drinking water analyses by direct aspiration, the final volume may be
reduced to effect up to a 10X concentration of the sample, provided the total
dissolved solids m the original sample do not exceed 500 mg/1, the determination
is corrected for any non-specific absorbance and there is no loss by precipitation
Interferences
5 1 Direct Aspiration
511 The most troublesome type of interference in atomic absorption
spectrophotometry is usually termed "chemical" and is caused by lack of
absorption of atoms bound in molecular combination in the flame This
phenomenon can occur when the flame is not sufficiently hot to dissociate the
molecule, as in the case of phosphate interference with magnesium, or because the
dissociated atom is immediately oxidized to a compound that will not dissociate
further at the temperature of the flame The addition of lanthanum will overcome
the phosphate interference in the magnesium, calcium and barium determinations
Similarly, silica interference in the determination of manganese can be eliminated
by the addition of calcium
512 Chemical interferences may also be eliminated by separating the metal from the
interfering material While complexmg agents are primarily employed to increase
the sensitivity of the analysis, they may also be used to eliminate or reduce
interferences
5 1 3 The presence of high dissolved solids m the sample may result in an interference
from non-atomic absorbance such as light scattering If background correction is
not available, a non-absorbing wavelength should be checked Preferably, high
solids type samples should be extracted (see 511 and 9 2)
514 lomzation interferences occur where the flame temperature is sufficiently high to
generate the removal of an electron from a neutral atom, giving a positive charged
ion This type of interference can generally be controlled by the addition, to both
standard and sample solutions, of a large excess of an easily ionized element
515 Although quite rare, spectral interference can occur when an absorbing
wavelength of an element present in the sample but not being determined falls
within the width of the absorption line of the element of interest The results of the
determination will then be erroneously high, due to the contribution of the
interfering element to the atomic absorption signal Also, interference can occur
METALS-7
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when resonant energy from another element in a multi-element lamp or a metal
impurity m the lamp cathode falls within the bandpass of the slit setting and that
metal is present in the sample This type of interference may sometimes be reduced
by narrowing the slit width
5.2 Flameless Atomization
521 Although the problem of oxide formation is greatly reduced with furnace
procedures because atomization occurs in an inert atmosphere, the technique is
still subject to chemical and matrix interferences The composition of the sample
matrix can have a major effect on the analysis It is those effects which must be
determined and taken into consideration in the analysis of each different matrix
encountered To help verify the absence of matrix or chemical interference use the
following procedure Withdraw from the sample two equal ahquots To one of the
ahquots add a known amount of analyte and dilute both ahquots to the same
predetermined volume [The dilution volume should be based on the analysis of the
undiluted sample Preferably, the dilution should be 1 4 while keeping in mind the
optimum concentration range of the analysis Under no circumstances should the
dilution be less than 1 1] The diluted ahquots should then be analyzed and the
unspiked results multiplied by the dilution factor should be compared to the
original determination Agreement of the results (within ±10%) indicates the
absence of interference Comparison of the actual signal from the spike to the
expected response from the analyte in an aqueous standard should help confirm the
finding from the dilution analysis Those samples which indicate the presence of
interference, should be treated in one or more of the following ways
a The samples should be successively diluted and reanalyzed to
determine if the interference can be eliminated
b The matrix of the sample should be modified in the furnace Examples
are the addition of ammonium nitrate to remove alkali chlorides,
ammonium phosphate to retain cadmium, and nickel nitrate for
arsenic and selenium analyses [ATOMIC ABSORPTION
NEWSLETTER Vol 14, No 5, p 127, Sept-Oct 1975] The mixing of
hydrogen with the inert purge gas has also been used to suppress
chemical interference The hydrogen acts as a reducing agent and aids
in molecular dissociation
c Analyze the sample by method of standard additions while noting the
precautions and limitations of its use (See 8 5)
522 Gases generated m the furnace during atomization may have molecular absorption
bands encompassing the analytical wavelength When this occurs, either the use of
background correction or choosing an alternate wavelength outside the absorption
band should eliminate this interference Non-specific broad band absorption
interference can also be compensated for with background correction
523 Interference from a smoke-producing sample matrix can sometimes be reduced by
extending the charring time at a higher temperature or utilizing an ashing cycle in
METALS-8
-------
the presence of air Care must be taken, however, to prevent loss of the analysis
element
524 Samples containing large amounts of organic materials should be oxidized by
conventional acid digestion prior to being placed in the furnace In this way broad
band absorption will be minimized
525 From anion interference studies in the graphite furnace it is generally accepted that
nitrate is the preferred anion Therefore nitric acid is preferable for any digestion or
solubihzation step If another acid in addition to HN03 is required a minimum
amount should be used This applies particularly to hydrochloric and to a lesser
extent to sulfunc and phosphoric acids
526 Carbide formation resulting from the chemical environment of the furnace has
been observed with certain elements that form carbides at high temperatures
Molybdenum may be cited as an example When this takes place, the metal will be
released very slowly from the carbide as atomization continues For molybdenum,
one may be required to atomize for 30 seconds or more before the signal returns to
baseline levels This problem is greatly reduced and the sensitivity increased with
the use of pyrolytically-coated graphite
527 lonization interferences have to date not been reported with furnace techniques
528 For comments on spectral interference see section 515
529 Contamination of the sample can be a major source of error because of the extreme
sensitivities achieved with the furnace The sample preparation work area should
be kept scrupulously clean All glassware should be cleaned as directed in part 6 9
of the Atomic Absorption Methods section of this manual Pipet tips have been
known to be a source of contamination If suspected, they should be acid soaked
with 1 5 HNO3 and rinsed thoroughly with tap and deiomzed water The use of a
better grade plpet tip can greatly reduce this problem It is very important that
special attention be given to reagent blanks in both analysis and the correction of
analytical results Lastly, pyrolytic graphite because of the production process and
handling can become contaminated As many as five to possibly ten high
temperature burns may be required to clean the tube before use
Apparatus
6 1 Atomic absorption spectrophotometer Single or dual channel, smgle-or double-beam
instrument having a grating monochromator, photomultipher detector, adjustable slits, a
wavelength range of 190 to 800 nm, and provisions for interfacing with a strip chart
recorder
6 2 Burner The burner recommended by the particular instrument manufacturer should be
used For certain elements the nitrous oxide burner is required
6 3 Hollow cathode lamps Single element lamps are to be preferred but multi-element lamps
may be used Electrodeless discharge lamps may also be used when available
6 4 Graphite furnace Any furnace device capable of reaching the specified temperatures is
satisfactory
METALS-9
-------
6 5 Strip chart recorder A recorder is strongly recommended for furnace work so that there
will be a permanent record and any problems with the analysis such as drift, incomplete
atomization, losses during charring, changes in sensitivity, etc, can be easily recognized
6 6 Pipets Microhter with disposable tips Sizes can range from 5 to 100 microhters as
required NOTE 7 Pipet tips which are white m color, do not contain CdS, and have
been found suitable for research work are available from Ulster Scientific, Inc 53 Mam
St Highland, NY 12528 (914) 691-7500
6.7 Pressure-reducing valves The supplies of fuel and oxidant shall be maintained at
pressures somewhat higher than the controlled operating pressure of the instrument by
suitable valves
6 8 Separatory flasks 250 ml, or larger, for extraction with organic solvents
6 9 Glassware All glassware, linear polyethylene, polyproplyene or Teflon containers,
including sample bottles, should be washed with detergent, rinsed with tap water, 1 1
nitric acid, tap water, 1 1 hydrochloric acid, tap water and deiomzed distilled water in
that order [See Notes 1 and 2 under (4 1) concerning the use of chromic acid and the
cleaning procedure ]
610 Borosilicate glass distillation apparatus
7. Reagents
7 1 Deiomzed distilled water Prepare by passing distilled water through a mixed bed of
cation and amon exchange resins Use deiomzed distilled water for the preparation of all
reagents, calibration standards, and as dilution water
7 2 Nitric acid (cone ) If metal impurities are found to be present, distill reagent grade
nitric acid m a borosilicate glass distillation apparatus or use a spectrograde acid
Caution Distillation should be performed in hood with protective sash in place
721 Nitric Acid (1 1) Prepare all dilution with deiomzed, distilled water by
adding the cone acid to an equal volume of water
7.3 Hydrochloric acid (11) Prepare all solution of reagent grade hydrochloric acid and
deiomzed distilled water If metal impurities are found to be present, distill this mixture
from a borosilicate glass distillation apparatus or use a spectrograde acid
7 4 Stock standard metal solutions Prepare as directed in (8 1) and under the individual
metal procedures Commercially available stock standard solutions may also be used
7 5 Calibration standards Prepare a series of standards of the metal by dilution of the
appropriate stock metal solution to cover the concentration range desired
7 6 Fuel and oxidant Commercial grade acetylene is generally acceptable Air may be
supplied from a compressed air line, a laboratory compressor, or from a cylinder of
compressed air Reagent grade nitrous oxide is also required for certain determinations
Standard, commercially available argon and nitrogen are required for furnace work
7 7 Special reagents for the extraction procedure
771 Pyrrohdine dithiocarbamic acid (PDCA) "see footnote" Prepare by adding 18
ml of analytical reagent grade pyrrohdme to 500 ml of chloroform in a liter flask
The name pyrrohdine dithiocarbamic acid (PDCA), although commonly referenced in the scientific
literature is ambiguous From the chemical reaction of pyrrohdme and carbon disulfide a more
proper name would be 1-pyrrolidme carbodithioic acid, PCDA (CAS Registry No 25769-03-3)
METALS-10
-------
(See Note 8) Cool and add 15 ml of carbon disulfide in small portions and with
swirling Dilute to 1 liter with chloroform The solution can be used for several
months if stored in a brown bottle in a refrigerator
NOTE 8: An acceptable grade of pyrrolidme may be obtained from the Aldnch
Chemical Co , 940 West St Paul Ave , Milwaukee, WI 53233(414,273-3850)
772 Ammonium hydroxide, 2N Dilute 13 ml cone NH4OH to 100 ml with
deiomzed distilled water
773 Bromophenol blue indicator (1 g/hter) Dissolve 0 1 g bromophenol blue m 100
ml of 50 percent ethanol or isopropanol
774 HC1,2 5% v/v Dilute 2 ml redistilled HC1 (6N) to 40 ml with deiomzed distilled
water
Preparation of Standards and Calibration
8 1 Stock standard solutions are prepared from high purity metals, oxides or nonhygroscopic
reagent grade salts using deiomzed distilled water and redistilled nitric or hydrochloric
acids (See individual analysis sheets for specific instruction ) Sulfuric or phosphoric
acids should be avoided as they produce an adverse effect on many elements The stock
solutions are prepared at concentrations of 1000 mg of the metal per liter Commercially
available standard solutions may also be used
8 2 Calibration standards are prepared by diluting the stock metal solutions at the time of
analysis For best results, calibration standards should be prepared fresh each time an
analysis is to be made and discarded after use Prepare a blank and at least four
calibration standards in graduated amounts in the appropriate range The calibration
standards should be prepared using the same type of acid or combination of acids and at
the same concentration as will result in the samples following processing As filtered
water samples are preserved with 1 1 redistilled HNO3 (3 ml per liter), calibration
standards for these analyses should be similarly prepared with HNO3 Beginning with
the blank and working toward the highest standard, aspirate the solutions and record the
readings Repeat the operation with both the calibration standards and the samples a
sufficient number of times to secure a reliable average reading for each solution
Calibration standards for furnace procedures should be prepared as described on the
individual sheets for that metal
8 3 Where the sample matrix is so complex that viscosity, surface tension and components
cannot be accurately matched with standards, the method of standard addition must be
used This technique relies on the addition of small, known amounts of the analysis
element to portions of the sample—the absorbance difference between those and the
original solution giving the slope of the calibration curve The method of standard
addition is described in greater detail in (8 5)
METALS-11
-------
8.4 For those instruments which do not read out directly in concentration, a calibration
curve is prepared to cover the appropriate concentration range Usually, this means the
preparation of standards which produce an absorption of 0 to 80 percent The correct
method is to convert the percent absorption readings to absorbance and plot that value
against concentration The following relationship is used to convert absorption values to
absorbance
absorbance = log (100/%T) == 2-log % T
where % T = 100-% absorption
As the curves are frequently nonlinear, especially at high absorption values, the number
of standards should be increased m that portion of the curve
8 5 Method of Standard Additions In this method, equal volumes of sample are added to a
deiomzed distilled water blank and to three standards containing different known
amounts of the test element The volume of the blank and the standards must be the
same The absorbance of each solution is determined and then plotted on the vertical axis
of a graph, with the concentrations of the known standards plotted on the horizontal
axis When the resulting line is extrapolated back to zero absorbance, the point of
interception of the abscissa is the concentration of the unknown The abscissa on the left
of the ordmate is scaled the same as on the right side, but in the opposite direction from
theordmate An example of a plot so obtained is shown in Fig 1
o>
o
o
J3
Zero
Absorbance
Concentration
'Cone of
Sample
Addn 0
No Addn
Addn I
Addn of 50%
of Expected
Amount
Addn 2
Addn of 100%
of Expected
Amount
Addn 3
Addn of 150%
of Expected
Amount
FIGURE 1. STANDARD ADDITION PLOT
METALS-12
-------
The method of standard additions can be very useful, however, for the results to be valid
the following limitations must be taken into consideration
a) the absorbance plot of sample and standards must be linear over the
concentration range of concern For best results the slope of the plot should
be nearly the same as the slope of the aqueous standard curve If the slope is
significantly different (more than 20%) caution should be exercised
b) the effect of the interference should not vary as the ratio of analyte
concentration to sample matrix changes and the standard addition should
respond in a similar manner as the analyte
c) the determination must be free of spectral interference and corrected for non-
specific background interference
General Procedure for Analysis by Atomic Absorption
9 1 Direct Aspiration Differences between the various makes and models of satisfactory
atomic absorption spectrophotometers prevent the formulation of detailed instructions
applicable to every instrument The analyst should follow the manufacturer's operating
instructions for his particular instrument In general, after choosing the proper hollow
cathode lamp for the analysis, the lamp should be allowed to warm up for a minimum of
15 minutes unless operated in a double beam mode During this period, align the
instrument, position the monochromator at the correct wavelength, select the proper
monochromator sht width, and adjust the hollow cathode current according to the
manufactuerer's recommendation Subsequently, light the flame and regulate the flow of
fuel and oxidant, adjust the burner and nebulizer flow rate for maximum percent
absorption and stability, and balance the photometer Run a series of standards of the
element under analysis and construct a calibration curve by plotting the concentrations
of the standards against the absorbance For those instruments which read directly in
concentration set the curve corrector to read out the proper concentration Aspirate the
samples and determine the concentrations either directly or from the calibration curve
Standards must be run each time a sample or series of samples are run
911 Calculation - Direct determination of liquid samples Read the metal value in
mg/1 from the calibration curve or directly from the readout system of the
instrument
9111 If dilution of sample was required
mg/1 metal in sample = A
where
A — mg/1 of metal indiluted aliquot from calibration curve
B = ml of deiomzed distilled water used for dilution
C= ml of sample aliquot
METALS-13
-------
912 For samples containing particulates
mg/1 metal m sample = /
where
A = mg/1 of metal m processed sample from calibration curve
V = final volume of the processed sample m ml
C = ml of sample aliquot processed
913 For solid samples report all concentrations as mg /kg dry weight
9131 Dry sample:
mg metal/kg sample = —g—
where
A = mg/1 of metal m processed sample from calibration curve
V = final volume of the processed sample in ml
D= weight of dry sample in grams
9132 Wet sample
A x V
mg metal/kg sample = „. v, p
W X sr
where
A = mg/1 of metal in processed sample from calibration curve
V = final volume of the processed sample m ml
W = weight of wet sample in grams
P = % solids
9 2 Special Extraction Procedure When the concentration of the metal is not sufficiently
high to determine directly, or when considerable dissolved solids are present in the
sample, certain metals may be chelated and extracted with organic solvents Ammonium
pyrrohdine dithiocarbamate (APDC) (see footnote) in methyl isobutyl ketone (MIBK) is
widely used for this purpose and is particularly useful for zinc, cadmium, iron,
manganese, copper, silver, lead and chromium"1"6 Tn-valent chromium does not react
with APDC unless it has first been converted to the hexavalent form [Atomic Absorption
Newsletter 6, p 128 (1967)] This procedure is described under method 218 3
The name ammonium pyrrohdine dithiocarbamate (APDC) is somewhat ambiguous and should more
properly be called ammonium, 1 -pyrrohdine carbodithioate (APCD), CAS Registry No 5108-96-3
METALS-14
-------
Aluminum, beryllium, barium and strontium also do not react with APDC While the
APDC-MIBK chelatmg-solvent system can be used satisfactorily, it is possible to
experience difficulties (See Note 9 )
NOTE 9: Certain metal chelates, manganese-APDC m particular, are not stable in
MIBK and will redissolve into the aqueous phase on standing The extraction of other
metals is sensitive to both shaking rate and time As with cadmium, prolonged extraction
beyond 1 minute, will reduce the extraction efficiency, whereas 3 minutes of vigorous
shaking is required for chromium
Also, when multiple metals are to be determined either larger sample volumes must be
extracted or individual extractions made for each metal being determined The acid form
of APDC-pyrrohdme dithiocarbamic acid prepared directly in chloroform as described
by Lakanen, [Atomic Absorption Newsletter 5, p 17 (1966)], (see 771) has been found
to be most advantageous In this procedure the more dense chloroform layer allows for
easy combination of multiple extractions which are carried out over a broader pH range
favorable to multielement extractions Pyrrohdme dithiocarbamic acid in chloroform is
very stable and may be stored in a brown bottle in the refrigerator for months Because
chloroform is used as the solvent, it may not be aspirated into the flame The following
procedure is suggested
921 Extraction procedure with pyrrohdme dithiocarbamic acid (PDCA) in
chloroform
9211 Transfer 200 ml of sample into a 250 ml separatory funnel, add 2 drops
bromphenol blue indicator solution (7 7 3) and mix
9212 Prepare a blank and sufficient standards in the same manner and adjust
the volume of each to approximately 200 ml with deiomzed distilled
water All of the metals to be determined may be combined into single
solutions at the appropriate concentration levels
9213 Adjust the pH by addition of 2N NH4OH solution (7 7 2) until a blue
color persists Add HC1 (7 7 4) dropwise until the blue color just
disappears, then add 2 0 ml HC1 (7 7 4) in excess The pH at this point
should be 2 3 (The pH adjustment may be made with a pH meter
instead of using indicator )
9214 Add 5 ml of PDCA-chloroform reagent (7 7 1) and shake vigorously
for 2 minutes Allow the phases to separate and dram the chloroform
layer into a 100 ml beaker (See NOTE 10 )
NOTE 10: If hexavalent chromium is to be extracted, the aqueous
phase must be readjusted back to a pH of 2 3 after the addition of
PDCA-chloroform and maintained at that pH throughout the
r extraction For multielement extraction, the pH may adjusted upward
after the chromium has been extracted
METALS-15
-------
9.2 1 5 Add a second portion of 5 ml PDCA-chloroform reagent (7 7 1) and
shake vigorously for 2 minutes Allow the phases to separate and
combine the chloroform phase with that obtained in step (9214)
9216 Determine the pH of the aqueous phase and adjust to 4 5
9217 Repeat step (9214) again combining the solvent extracts
9218 Readjust the pH to 5 5, and extract a fourth tune Combine all extracts
and evaporate to dryness on a steam bath
9.2 1 9 Hold the beaker at a 45 degree angle, and slowly add 2 ml of cone
distilled nitric acid, rotating the beaker to effect thorough contact of
the acid with the residue
9 2 1 10 Place the beaker on a low temperature hotplate or steam bath and
evaporate just to dryness
92111 Add 2 ml of nitric acid (1 1) to the beaker and heat for 1 minute Cool,
quantitatively transfer the solution to a 10 ml volumetric flask and
bring to volume with distilled water The sample is now ready for
analysis
9.2 2 Prepare a calibration curve by plotting absorbance versus the concentration of the
metal standard (ug/1) in the 200 ml extracted standard solution To calculate
sample concentration read the metal value in ug/1 from the calibration curve or
directly from the readout system of the instrument If dilution of the sample was
required use the following equation
mg/1 metal m sample
where
Z = ug/1 of metal in diluted aliquot from calibration curve
B = ml of deiomzed distilled water used for dilution
C = ml of sample aliquot
9 3 Furnace Procedure Furnace devices (flameless atomization) are a most useful means of
extending detection limits Because of differences between various makes and models of
satisfactory instruments, no detailed operating instuctions can be given for each
instrument Instead, the analyst should follow the instructions provided by the
manufacturer of his particular instrument and use as a guide the temperature settings
and other instrument conditions listed on the individual analysis sheets which are
recommended for the Perkm-Elmer HGA-2100 In addition, the following points may be
helpful
931 With flameless atomization, background correction becomes of high importance
especially below 350 nm This is because certain samples, when atomized, may
absorb or scatter light from the hollow cathode lamp It can be caused by the
presence of gaseous molecular species, salt particules, or smoke in the sample
METALS-16
-------
beam If no correction is made, sample absorbance will be greater than it should be,
and the analytical result will be erroneously high
9 3 2 If during atomization all the analyte is not volatilized and removed from the
furnace, memory effects will occur This condition is dependent on several factors
such as the volatility of the element and its chemical form, whether pyrolytic
graphite is used, the rate of atomization and furnace design If this situation is
detected through blank burns, the tube should be cleaned by operating the furnace
at full power for the required time period as needed at regular intervals in the
analytical scheme
933 Some of the smaller size furnace devices, or newer furnaces equipped with feedback
temperature control (Instrumentation Laboratories MODEL 555, Perkm-Elmer
MODELS HGA 2200 and HGA 76B, and Varian MODEL CRA-90) employing
faster rates of atomization, can be operated using lower atomization temperatures
for shorter time periods than those listed in this manual
934 Although prior digestion of the sample in many cases is not required providing a
representative aliquot of sample can be pipeted into the furnace, it will provide for a
more uniform matrix and possibly lessen matrix effects
935 Inject a measured microhter aliquot of sample into the furnace and atomize If the
concentration found is greater than the highest standard, the sample should be
diluted in the same acid matrix and reanalyzed The use of multiple injections can
improve accuracy and help detect furnace pipetting errors
9 3 6 To verify the absence of interference, follow the procedure as given in part 521
9 3 7 A check standard should be run approximately after every 10 sample injections
Standards are run in part to monitor the life and performance of the graphite tube
Lack of reproducibihty or significant change in the signal for the standard
indicates that the tube should be replaced Even though tube life depends on
sample matrix and atomization temperature, a conservative estimate would be that
a tube will last at least 50 firings A pyrolytic-coatmg would extend that estimate
by a factor of 3
938 Calculation-For determination of metal concentration by the furnace Read the
metal value in ug/1 from the calibration curve or directly from the readout system
of the instrument
9381 If different size furnace injection volumes are used for samples than for
standards
-'(*)
ug/1 of metal in sample =
where
Z = ug/1 of metal read from calibration curve or readout system
S = ul volume standard injected into furnace for calibration curve
U = ul volume of sample injected for analysis
METALS-17
-------
9382 If dilution of sample was required but sample injection volume same as
for standard
ug/1 of metal in sample = Z
where
Z = ug/1 metal in diluted aliquot from calibration curve
B = ml of deiomzed distilled water used for dilution
C = ml of sample aliquot
939 For sample containing particulates
ug/1 of metal in sample = Z I TT
where
Z = ug/1 of metal in processed sample from calibration curve (See 9381)
V = final volume of processed sample in ml
C = ml of sample aliquot processed
9310 For solid samples Report all concentrations as mgAg dry weight
9 3 10 1 Dry sample
x1,000 ^V
mg metal/kg sample =
where
Z = ug/1 of metal in processed sample from calibration curve (See 9381)
V = final volume of processed sample in ml
D= weight of dry sample in grams
93102 Wet sample
[,000 ' V
mg metal/kg sample =
W X A
where
Z = ug/1 of metal in processed sample from calibration curve (See 9381)
V = final volume of processed sample in ml
W = weight of wet sample in grams
P = % solids
METALS-18
-------
10 Quality Control For Drinking Water Analysis
10 1 Minimum requirements l
10 1 1 All quality control data should be maintained and available for easy
reference or inspection
10 1 2 An unknown performance sample (when available) must be analyzed once
per year for the metals measured Results must be within the control limit
established by EPA If problems arise, they should be corrected, and a
follow-up performance sample should be analyzed
10 2 Minimum Daily control
10 2 1 After a calibration curve compojsed of a minimum of a reagent blank and
three standards has been prepared, subsequent calibration curves must be
verified by use of at least a reagent blank and one standard at or near the
MCL Daily checks must be within ±10 percent of original curve
1022 If 20 or more samples per day are [analyzed, the working standard curve must
be verified by running an additional standard at or near the MCL every 20
samples Checks must be within i 10 percent of original curve
10 3 Optional Requirements
10 3 1 A current service contract should be in effect on balances and the atomic
absorption spectrophotometer j
1032 Class S weights should be available to make periodic checks on balances
1033 Chemicals should be dated upon receipt of shipment and replaced as needed
or before shelf life has been exceedjed
10 3 4 A known reference sample (when available) should be analyzed once per
quarter for the metals measured |xhe measured value should be within the
control limits established by EPA'
10 3 5 At least one duplicate sample should be run every 10 samples, or with each
set of samples to verify precision of the method Checks should be within the
control limit established by EPA
10 3 6 Standard deviation should be obtained and documented for all
measurements being conducted |
10 3 7 Quality Control charts or a tabulation of mean and standard deviation
should be used to document vahdi(y of data on a daily ba
basis
METALS-19
-------
United States
Environmental Protection
Agency
Environmental Monitoring and
Support Laboratory
Cincinnati OH 45268
Research and Development
•ERA
Test Method
Inductively Coupled Plasma—
Atomic Emission Spectrometric
Method for Trace Element
Analysis of Water and
Wastes—Method 200.7
1 Scope and Application
1 1 This method may be used for
the determination of dissolved
suspended, or total elements in
drinking water, surface water
domestic and industrial wastewaters
1 2 Dissolved elements are
determined in filtered and acidified
samples Appropriate steps must be
taken in all analyses to ensure that
potential interference are taken into
account This is especially true when
dissolved solids exceed 1 500 mg/L
(See 5 )
1 3 Total elements are determined
after appropriate digestion procedures
are performed Since digestion
techniques increase the dissolved
solids content of the samples,
appropriate steps must be taken to
correct for potential interference
effects (See 5 )
1 4 Table 1 lists elements for which
this method applies along with
recommended wavelengths and
typical estimated instrumental
detection limits using conventional
pneumatic nebuhzation Actual
working detection limits are sample
dependent and as the sample matrix
varies, these concentrations may also
vary In time, other elements may be
added as more information becomes
available and as required
1 5 Because of the differences
between various makes and models of
satisfactory instruments, no detailed
instrumental operating instructions
can be provided Instead, the analyst
is referred to the instructions provided
by the manufacturer of the particular
instrument
2 Summary of Method
2 1 The method describes a
technique for the simultaneous or
sequential multielement
determination of trace elements in
solution The basis of the method is
the measurement of atomic emission
by an optical spectroscopic technique
Samples are nebulized and the
aerosol that is produced is transported
to the plasma torch where excitation
occurs Characteristic atomic-line
emission spectra are produced by a
radio-frequency inductively coupled
plasma (ICP) The spectra are
dispersed by a grating spectrometer
and the intensities of the lines are
monitored by photomultipher tubes
The photocurrents from the
photomultipher tubes are processed
and controlled by a computer system
A background correction technique is
required to compensate for variable
background contribution to the
Metals-2O
Dec 1982
-------
determination of trace elements
Background must be measured
adjacent to analyte lines on samples
during analysis The position selected
for the background intensity
measurement on either or both sides
of the analytical line, will be
determined by the complexity of the
spectrum adjacent to the analyte line
The position used must be free of
spectral interference and reflect the
same change in background
intensity as occurs at the analyte
wavelength measured Background
correction is not required in cases of
line broadening where a background
correction measurement would
actually degrade the analytical result
The possibility of additional
interferences named in 5 1 (and tests
for their presence as described in 5 2)
should also be recognized and
appropriate corrections made
3 Definitions
3 1 Dissolved — Those elements
which will pass through a 0 45 /urn
membrane filter
3 2 Suspended — Those elements
which are retained by a 0 45 fjm
membrane filter
3 3 Total — The concentration
determined on an unfiltered sample
following vigorous digestion (9 3) or
the sum of the dissolved plus
suspended concentrations (9 1 plus
92)
3 4 Total recoverable — The
concentration determined on an
unfiltered sample following treatment
with hot dilute mineral acid (9 4)
3 5 Instrumental detection limit —
The concentration equivalent to a
signal, due to the analyte which is
equal to three times the standard
deviation of a series of ten replicate
measurements of a reagent blank
signal at the same wavelength
3 6 Sensitivity — The slope of the
analytical curve, i e functional
relationship between emission
intensity and concentration
3 7 Instrument check standard — A
multielement standard of known
concentrations prepared by the
analyst to monitor and verify
instrument performance on a daily
basis (See 761)
3 8 Interference check sample — A
solution containing both interfering
and analyte elements of known
concentration that can be used to
verify background and mterelement
correction factors (See 762)
3 9 Quality control sample — A
solution obtained from an outside
source having known, concentration
values to be used to verify the
calibration standards (See 763)
3 10 Calibration standards — a
series of know standard solutions
used by the analyst for calibration of
the instrument (i e , preparation of the
analytical curve) (See 7 4)
311 Linear dynamic range — The
concentration range over which the
analytical curve remains linear
3 12 Reagent blank — A volume of
deionized distilled water containing
the same acid matrix as the
calibration standards carried through
the entire analytical scheme (See
752)
3 13 Calibration blank — A volume
of deionized distilled water acidified
with HNO3 and HCI (See 751)
3 14 Method of standard addition —
The standard addition technique
involves the use of the unknown and
the unknown plus a known amount of
standard (See 1061)
4 Safety
4 1 The toxicity or carcmogenicity of
each reagent used in this method has
not been precisely defined however
each chemical compound should be
treated as a potential health hazard
From this viewpoint exposure to
these chemicals must be reduced to
the lowest possible level by whatever
means available The laboratory is
responsible for maintaining a current
awareness file of OSHA regulations
regarding the safe handling of the
chemicals specified in this method A
reference file of material data
handling sheets should also be made
available to all personnel involved in
the chemical analysis Additional
references to laboratory safety are
available and have been identified
(147 148 and 14 9) for the
information of the analyst
5 Interferences
5 1 Several types of interference
effects may contribute to inaccuracies
in the determination of trace
elements They can be summarized as
follows
511 Spectral interferences can be
categorized as 1) overlap of a spectral
line from another element, 2)
unresolved overlap of molecular band
spectra, 3) background contribution
from continuous or recombination
phenomena, and 4) background
contribution from stray light from the
line emission of high concentration
elements The first of these effects
can be compensated by utilizing a
computer correction of the raw data,
requiring the monitoring and
measurement of the interfering
element The second effect may
require selection of an alternate
wavelength The third and fourth
effects can usually be compensated by
a background correction adjacent to
the analyte line In addition, users of
simultaneous multielement
instrumentation must assume the
responsibility of verifying the absence
of spectral interference from an
element that could occur in a sample
but for which there is no channel in
the instrument array Listed in Table 2
are some interference effects for the
recommended wavelengths given in
Table 1 The data in Table 2 are
intended for use only as a
rudimentary guide for the indication of
potential spectral interferences For
this purpose, linear relations between
concentration and intensity for the
analytes and the mterferents can be
assumed
The interference information which
was collected at the Ames Laboratory,1
is expressed at analyte concentration
eqivalents (i e false analyte concen-
trations) arising from 1OO mg/L of the
mterferent element The suggested use
of this information is as follows
Assume that arsenic (at 193 696 nm)
is to be determined in a sample
containing approximately 10 mg/L of
aluminum According to Table 2, 100
mg/L of aluminum would yield a false
signal for arsenic equivalent to
approximately 1 3 mg/L Therefore,
10 mg/L of aluminum would result in
a false signal for arsenic equivalent to
approximately 0 13 mg/L The reader
is cautioned that other analytical
systems may exhibit somewhat
different levels of interference than
those shown in Table 2, and that the
interference effects must be evaluated
for each individual system
Only those mterferents listed werp
investigated and the blank spaces in
Table 2 indicate that measurable inter-
ferences were not observed for the
mterferent concentrations listed in
Table 3 Generally interferences were
discernible if they produced peaks or
background shifts corresponding to
2-5% of the peaks generated by the
'Ames Laboratory USDOE Iowa State University
Ames Iowa 50011
Dec 1982
Metals-21
-------
analyte concentrations also listed in
Table 3
At present, information on the listed
silver and potassium wavelengths are
not available but it has been reported
that second order energy from the
magnesium 383 231 nm wavelength
interferes with the listed potassium line
at 766 491 nm
5.1.2 Physical interferences are
generally considered to be effects
associated with the sample nebuhza-
tion and transport processes Such
properties as change in viscosity and
surface tension can cause significant
inaccuracies especially in samples
which may contain high dissolved
solids and/or acid concentrations The
use of a peristaltic pump may lessen
these interferences If these types of
interferences are operative, they must
be reduced by dilution of the sample
and/or utilization of standard addition
techniques Another problem which
can occur from high dissolved solids
is salt buildup at the tip of the
nebulizer This affects aersol flow-rate
causing instrumental drift Wetting
the argon prior to nebulization, the
use of a tip washer, or sample dilution
have been used to control this
problem. Also, it has been reported
that better control of the argon flow
rate improves instrument
performance This is accomplished
with the use of mass flow controllers
5 1.3 Chemical Interferences are
characterized by molecular compound
formation, lonlzation effects and
solute vaporization effects Normally
these effects are not pronounced with
the ICP technique, however, if
observed they can be minimized by
careful selection of operating
conditions (that is, incident power,
observation position, and so forth), by
buffering of the sample, by matrix
matching, and by standard addition
procedures These types of
interferences can be highly dependent
on matrix type and the specific
analyte efement
5.2 It is recommended that
whenever a new or unusual sample
matrix is encountered, a series of
tests be performed prior to reporting
concentration data for analyte
elements These tests, as outlined in
521 through 524, will ensure the
analyst that neither positive nor
negative interference effects are
operative on any of the analyte el-
ements thereby distorting the
accuracy of the reported values
521 Serial dilution—If the analyte
concentration is sufficiently high (min-
imally a factor of 10 above the instru-
mental detection limit after dilution),
an analysis of a dilution should agree
within 5 % of the original determina-
tion (or within some acceptable con-
trol limit (14 3) that has been estab-
lished for that matrix) If not, a
chemical or physical interference ef-
fect should be syspected
522 Spike addition—The recovery
of a spike addition added at a
minimum level of 10X the in-
strumental detection limit (maximum
100X) to the original determination
should be recovered to within 90 to
110 percent or within the established
control limit for that matrix If not, a
matrix effect should be suspected The
use of a standard addition analysis
procedure can usually compensate for
this effect Caution The standard ad-
dition technique does not detect coin-
cident spectral overlap If suspected,
use of computerized compensation, an
alternate wavelength, or comparison
with an alternate method is recom-
mended (See 523)
523 Comparison with alternate
method of analysis—When investi-
gating a new sample matrix, compari-
son tests may be performed with other
analytical techniques such as atomic
absorption spectrometry, or other
approved methodology
524 Wavelength scanning of
analyte line region—\i the appropriate
equipment is available, wavelength
scanning can be performed to detect
potential spectral interferences
6 Apparatus
6 1 Inductively Coupled Plasma-
Atomic Emission Spectrometer
611 Computer controlled atomic
emission spectrometer with background
correction
612 Radiofrequency generator
613 Argon gas supply, welding
grade or better
6 2 Operating conditions — Because
of the differences between various
makes and models of satisfactory
instruments, no detailed operating
instructions can be provided Instead,
the analyst should follow the
instructions provided by the
manufacturer of the particular
instrument Sensitivity, instrumental
detection limit, precision, linear dy-
namic range, and interference effects
must be investigated and established
for each individual analyte line on that
particular instrument It is the
responsibility of the analyst to verify
that the instrument configuration and
operating conditions used satisfy the
analytical requirements and to
maintain quality control data
confirming instrument performance
and analytical results
7 Reagents and standards
7 1 Acids used in the preparation
of standards and for sample processing
must be ultra-high purity grade or
equivalent Redistilled acids are
acceptable
777 Acetic acid, cone (sp gr 1 06)
7/2 Hydrochloric acid cone (sp gr
1 19)
713 Hydrochloric acid, (1+1) Add
500 ml cone HCI (sp gr 1 19) to 400
mL deiomzed, distnlled water and
dilute to 1 liter
714 Nitric acid cone (sp gr 1 41)
7/5 Nitric ac/o:(1+1) Add 500 mL
cone HN03 (sp gr 1 41) to 400 ml
deiomzed, distilled water and dilute to
1 liter
7 2 Dionized distilled water Prepare
by passing distilled water through a
mixed bed of cation and anion ex-
change resins Use deiomzed, distilled
water for the preparation of all
reagents, calibration standards and as
dilution water The purity of this water
must be equivalent to ASTM Type II
reagent water of Specification D 1193
(146)
7 3 Standard stock solutions may be
purchased or prepared from ultra high
purity grade chemicals or metals All
salts must be dried for 1 h at 105°C
unless otherwise specified
(CAUTION Many metal salts are ex-
tremely toxic and may be fatal if swal-
lowed Wash hands thoroughly after
handling ) Typical stock solution pre-
paration procedures follow
731 Aluminum solution, stock, 1
mL = 100 yug Al Dissolve 0 100 g of
aluminum metal in an acid mixture of 4
mL of (1+1) HCI and 1 mL of cone HNO3
in a beaker Warm gently to effect
solution When solution is complete,
transfer quantitatively to a liter flask,
add an additional 10 mL of (1 + 1) HCI
and dilute to 1 000 mL with deiomzed,
distilled water
732 Antimony solution stock, 1 mL
= 100 //g Sb Dissolve 0 2669 g K(SbO)
C^iH/iOe in deiomzed distilled water,
add 10 mL (1+1) HCI and dilute
to 1000 mL with deiomzed, distilled
water
Metals-22
Dec 1982
-------
733 Arsenic solution stock, 1 mL =
TOO /jig As Dissolve 0 1320 g of As2O3
in 100 mL of deiomzed, distilled water
containing 0 4 g NaOH Acidify the
solution with 2 mL cone HNO3 and
dilute to 1,000 mL with deiomzed
distilled Water
734 Barium solution stock 1 mL
= 100 ,ug Ba Dissolve 0 1516 g BaCI2
(dried at 250°C for 2 hrs) in 10 mL
deiomzed, distilled water with 1 mL
(1+1) HCI Add 100 mL(1+1) HCI
and dilute to 1,000 mL with deiomzed,
distilled water
735 Beryllium solution stock 1
mL = 100 HQ Be Do not dry Dis-
solve 1 966 g BeSCU 4 4H2O in
deiomzed, distilled water add 100 mL
cone HN03 and dilute to 1 000 mL
with deiomzed, distilled water
736 Boron solution stock, 1 mL
= 100 //g B Do not dry Dissolve
0 5716 g anhydrous H3BO3 in deiomzed
distilled water dilute to 1,000 mL
Use a reagent meeting ACS specifica-
tions, keep the bottle tightly stoppered
and store in a desiccator to prevent
the entrance of atmospheric moisture
737 Cadmium solution stock 1
mL = 100 fj.g Cd Dissolve 0 1142 g
CdO in a minimum amount of (1 + 1)
HNO3 Heat to increase rate of dis-
solution Add 10 OmL cone HIM03
and dilute to 1,000 mL with deiomzed,
distilled water
738 Calcium solution stock 1 mL
= 100 ^g Ca Suspend 0 2498 g
CaCO3 dried at 180°C for 1 h before
weighing in deiomzed distilled water
and dissolve cautiously with a min-
imum amount of (1 + 1) HN03 Add
10 OmL cone HNO3 and dilute to
1,000 mL with deiomzed distilled
water
739 Chromium solution stock 1
mL = 100 /jg Cr Dissolve 0 1923
g of Cr03 m deiomzed, distilled
water When solution is complete,
acidify with 10 mL cone HNO3 and
dilute to 1,000 mL with deiomzed
distilled water
73 JO Cobalt solution stock 1
mL = 100/jg Co Dissolve 0 1000 g
of cobalt metal in a minimum amount
of (1+1) HNO3 Add 100 mL (1+1) HCI
and dilute to 1,000 mL with deiomzed
distilled water
7311 Copper solution stock 1
mL = 100 fig Cu Dissolve 0 1 252 g
CuO in a minimum amount of (1 + 1)
HNO3 Add 10 OmL cone HN03 and
dilute to 1 000 mL with deiomzed
distilled water
7312 Iron solution stock 1 mL
= 100/ug Fe Dissolve 0 1430 g
Fe2O3 in a warm mixture of 20 mL
(1+1) HCI and 2 mL of cone HNO3
Cool, add an additional 5 mL of cone
HN03 and dilute to 1000 mL with
deiomzed, distilled water
7313 Lead solution stock 1 mL
= 100 fjg Pb Dissolve 0 1599 g
Pb(IMO3)2 in minimum amount of
(1+1) HN03 Add 10 OmL cone HNO3
and dilute to 1,000 mL with deiomzed,
distilled water
7314 Magnesium solution stock 1
mL = 100/ug Mg Dissolve 0 1658 g
MgO m a minimum amount of (1 + 1)
HNO3 Add 10 OmL cone HNO3 and
dilute to 1,000 mL with deiomzed,
distilled water
73 15 Manganese solution stock 1
mL = 100yug Mn Dissolve 0 1000 g
of manganese metal in the acid mix-
ture 10 mL cone HCI and 1 mL cone
HNO3, and dilute to 1,000 mL with
deiomzed distilled water
7316 Molybdenum solution stock
1 mL = 100 yt/g Mo Dissolve 0 2043 g
(NH4)2MoCU m deiomzed distilled
water and dilute to 1 000 mL
7317 Nickel solution stock 1
mL = 100 yug Ni Dissolve 0 1000 g
of nickel metal in 10 mL hot cone
HNO3, cool and dilute to 1,000 mL
with deiomzed, distilled water
7318 Potassium solution stock 1
mL = 100 /ug K Dissolve 0 1907 g
KCI, dried at 110°C m deiomzed
distilled water dilute to 1 000 mL
7319 Selenium solution stock 1
mL = 100 /ug Se Do not dry Dissolve
0 1 727 g H2SeO3 (actual assay 94 6%)
in deiomzed distilled water and dilute
to 1,000 mL
7 3 20 Silica solution stock 1 mL
= 100y(/g SiO2 Do not dry Dissolve
0 4730 g Na2SiO3 9H20 in deiomzed
distilled water Add 10 0 mL cone
HNO3 and dilute to 1,000 mL with
deiomzed distilled water
7 3 21 Silver solution stock 1
mL = 100 fig Ag Dissolve 0 1575 g
AgNO3 in 100 mL of deiomzed dis-
tilled water and 10 mL cone HNO3
Dilute to 1 000 mL with deiomzed
distilled water
7 3 22 Sodium solution stock 1
mL = 100 yug Na Dissolve 0 2542 g
NaCI in deiomzed distilled water
Add 10 OmL cone HNO3 and dilute
to 1 000 mL with deiomzed distilled
water
7 3 23 Thallium solution, stock, 1
mL = 100 yug Tl Dissolve 0 1303 g
TINO3 iri deiomzed, distilled water
Add 10 0 mL cone HN03 and dilute
to 1,000 mL with deiomzed, distilled
water
7 3 24 Vanadium solution stock, 1
mL = 100 fig V Dissolve 0 2297
NH/A/Os m a minimum amount of
cone HN03 Heat to increase rafe
of dissolution Add 10 0 mL cone
HN03 and dilute to 1,000 mL with
deiomzed distilled water
7 3 25 Zinc solution stock 1 mL
= 100 //g Zn Dissolve 0 1245 g ZnO
in a minimum amount of dilute HIMOa
Add 10 0 mL cone HNO3 and dilute
to 1,000 mL with deiomzed, distilled
water
7 4 Mixed calibration standard so-
lutions—Prepare mixed calibration
standard solutions by combining ap-
propriate volumes of the stock solu-
tions in volumetric flasks (See 7 4 1
thru 745) Add 2 mL of (1 + 1)
HCI and dilute to 100 mL with
deiomzed, distilled water (See Notes
1 and 6 ) Prior to preparing the mixed
standards each stock solution should
be analyzed separately to determine
possible spectral interference or the
presence of impurities Care should
be taken when preparing the mixed
standards that the elements are com-
patible and stable Transfer the mixed
standard solutions to a FEP fluoro-
carbon or unused polyethylene bottle
for storage Fresh mixed standards
should be prepared as needed with
the realization that concentration can
change on aging Calibration stand-
ards must be initially verified using
a quality control sample and moni-
tored weekly for stability (See 763)
Although not specifically required,
some typical calibration standard com-
binations follow when using those
specific wavelengths listed in Table
1
741 Mixed standard solution I—
Manganese beryllium cadmium lead
and zinc
742 Mixed standard solution II—
Barium, copper, iron vanadium and
cobalt
743 Mixed standard solution III—
Molybdenum silica arsenic, and
selenium
744 Mixed standard solution IV—
Calcium sodium potassium alumi-
num chromium and nickel
Dec 1982
Meta/s-23
-------
745 Mixed standard solution V—
Antimony, boron, magnesium, silver,
and thallium
NOTE 1 If the addition of silver
to the recommended acid combination
results in an initial precipitation,
add 15 ml of deionized distilled
water and warm the flask until the
solution clears Cool and dilute to 100
mL with deionized, distilled water For
this acid combination the silver con-
centration should be limited to 2
mg/L Silver under these conditions
Is stable in a tap water matrix
for 30 days Higher concentrations
of silver require additional HCI
7 5 Two types of blanks are required
for the analysis The calibration blank
(3 13) is used in establishing the
analytical curve while the reagent
blank (3 12) is used to correct for
possible contamination resulting from
varying amounts of the acids used m
the sample processing
7 5.1 The calibration blank is pre-
pared by diluting 2 mLof (1+1) HNO3
and 10 mL of (1+1) HCI to 100 mL
with deionized, distilled water (See
Note 6 ) Prepare a sufficient quantity
to be used to flush the system be-
tween standards and samples
752 The reagent blank must con-
contain all the reagents and in the
same volumes as used in the pro-
cessing of the samples The reagent
blank must be carried through the
complete procedure and contain the
same acid concentration in the final
solution as the sample solution
used for analysis
7.6 In addition to the calibration
standards, an instrument check stan-
dard (3 7), an interference check
sample (3 8) and a quality control
sample (3 9) are also required for the
analyses
761 The instrument check standard
is prepared by the analyst by com-
bining compatible elements at a con-
centration equivalent to the midpoint
of their respective calibration curves
(See 121 1)
752 The interference check sample
is prepared by the analyst in the
following manner Select a
representative sample which contains
minimal concentrations of the
analytes of interest by known con-
centration of interfering elements that
will provide an adequate test of the
correction factors Spike the sample
with the elements of interest at the
approximate concentration of either
100 /ug/L or 5 times the estimated
detection limits given in Table 1 (For
effluent samples of expected high
concentrations, spike at an
appropriate level) If the type of
samples analyzed are varied a
synthetically prepared sample may be
used if the above criteria and intent
are met A limited supply of a
synthetic interference check sample
will be available from the Quality
Assurance Branch of EMSL-
Cmcmnati (See 1212)
753 The quality control sample
should be prepared in the same acid
matrix as the calibration standards
at a concentration near 1 mg/L and in
accordance with the instructions
provided by the supplier The Quality
Assurance Branch of EMSL-Cmcmnati
will either supply a quality control
sample or information where one of
equal quality can be procured (See
1213)
8 Sample handling an
preservation
8 1 For the determination of trace
elements, contamination and loss are
of prime concern Dust in the labora-
tory environment impurities in
reagents and impurities on laboratory
apparatus which the sample contacts
are all sources of potential
contamination Sample containers can
introduce either positive or negative
errors in the measurement of trace
elements by (a) contributing con-
taminants through leaching or surface
desorption and (b) by depleting
concentrations through adsorption
Thus the collection and treatment of
the sample prior to analysis requires
particular attention Laboratory
glassware including the sample bottle
(whether polyethylene, polyproplyene
or FEP-fluorocarbon) should be
thoroughly washed with detergent
and tap water, rinsed with (1+1) nitric
acid, tap water, (1+1) hydrochloric
acid, tap and finally deionized, distilled
water in that order (See Notes 2 and
3)
NOTE 2 Chromic acid may be useful to
remove organic deposits from glass-
ware, however, the analyst should be
be cautioned that the glassware must
be thoroughly rinsed with water to
remove the last traces of chromium
This is especially important if chromium
is to be included in the analytical
scheme A commercial product, NOCH-
ROMIX, available from Godax Labor-
atories, 6 Varick St, New York, NY
10013, may be used in place of
chromic acid Chomic acid should not
be used with plastic bottles
NOTES Ifitcanbedocumentedthrough
an active analytical quality control
program using spiked samples and re-
agent blanks, that certain steps m the
cleaning procedure are not required for
routine samples, those steps may be
eliminated from the procedure
8 2 Before collection of the sample a
decision must be made as to the type
of data desired, that is dissolved,
suspended or total, so that the appro-
priate preservation and pretreatment
steps may be accomplished Filtration,
acid preservation, etc , are to be per-
formed at the time the sample is
collected or as soon as possible
thereafter
821 For the determination of dis-
solved elements the sample must be
filtered through a 045-yum membrane
filter as soon as practical after collec-
tion (Glass or plastic filtering appara-
tus are recommended to avoid possi-
ble contamination ) Use the first 50-
100 mL to rinse the filter flask Dis-
card this portion and collect the
required volume of filtrate Acidify the
filtrate with (1 +1) HNO3 to a pH of 2
or less Normally, 3 mL of (1+1) acid
per liter should be sufficient to pre-
serve the sample
822 For the determination of sus-
pended elements a measured volume
of unpreserved sample must be fil-
tered through a 045-/t/m membrane
filter as soon as practical after
collection The filter plus suspended
material should be transferred to a
suitable container for storage and/or
shipment No preservative is required
823 For the determination of total
or total recoverable elements, the
sample is acidified with (1+1) HNOs
to pH 2 or less as soon as possible,
preferable at the time of collection
The sample is not filtered before
processing
9 Sample Preparation
9 1 For the determinations of dis-
solved elements, the filtered,
preserved sample may often be
analyzed as received The acid matrix
and concentration of the samples and
calibration standards must be the
same (See Note 6) If a precipitate
formed upon acidification of the
sample or during transit or storage, it
must be redissolved before the
analysis by adding additional acid
and/or by heat as described m 9 3
9 2 For the determination of sus-
pended elements, transfer the mem-
brane filter containing the insoluble
material to a 150-mL Griffin beaker
and add 4 mL cone HNOs Cover the
Metals-24
Dec 1982
-------
beaker with a watch glass and heat
gently The warn acid will soon dis-
solve the membrane
Increase the temperature of the
hot plate and digest the material
When the acid has nearly evaporated
cool the beaker and watch glass and
add another 3 mL of cone HIMO3
Cover and continue heating until the
digestion is complete generally indi-
cated by a light colored digestate
Evaporate to near dryness (2 mL), cool
add lOmLHCI (1+1) and 15 mL
deionized distilled water per 100 mL
dilution and warm the beaker gently
for 15 mm to dissolve any precipi-
tated or residue material Allow to
cool, wash down the watch glass and
beaker walls with deionized distilled
water and filter the sample to remove
insoluble material that could clog the
nebulizer (See Note 4 ) Adjust the
volume based on the expected con-
centrations of elements present This
volume will vary depending on the
elements to be determined (See Note
6) The sample is now ready for
analysis Concentrations so determined
shall be reported as suspended
NOTE 4 In place of filtering, the
sample after diluting and mixing may
be centnfuged or allowed to settle by
gravity overnight to remove insoluble
material
9 3 For the determination of total
elements, choose a measured, volume
of the well mixed acid preserved
sample appropriate for the expected
level of elements and transfer to a
Griffin beaker (See Note 5 ) Add 3 mL
of cone HNO3 Place the beaker on
a hot plate and evaporate to near dry-
ness cautiously, making certain that
the sample does not boil and that no
area of the bottom of the beaker is
allowed to go dry Cool the beaker and
add another 5 mL portion of cone
HNO3 Cover the beaker with a watch
glass and return to the hot plate
Increase the temperature of the hot
plate so that a gentle reflux action
occurs Continue heating, adding addi-
tional acid as necessary, until the
digestion is complete (generally indi-
cated when the digestate is light
in color or does not change in appear-
ance with continued refluxmg ) Again
evaporate to near dryness and cool
the beaker Add 10 mL of 1+1 HCI
and 15 mL of deionized distilled
water per 100 mL of final solution
and warm the beaker gently for 15
mm to dissolve any precipitate or
residue resulting from evaporation
Allow to cool, wash down the beaker
walls and watch glass with deionized
distilled water and filter the sample to
remove insoluble material that could
clog the nebulizer (See Note 4 ) Adjust
the sample to a predetermined volume
based on the expected concentrations
of elements present The sample is
now ready for analysis (See Note 6)
Concentrations so determined shall be
reported as total
NOTE 5 If low determinations of
boron are critical, quartz glassware
should be use
NOTE 6 If the sample analysis solution
has a different acid concentration
from that given in 9 4, but does not
introduce a physical interference or
affect the analytical result the same
calibration standards may be used
9 4 For the determination of total
recoverable elements choose a mea-
sured volume of a well mixed, acid
preserved sample appropriate for the
expected level of elements and trans-
fer to a Griffin beaker (See Note 5 )
Add 2 mL of (1+1) HNO3 and 10 mL
of (1+1) HCI to the sample and heat
on a steam bath or hot plate until the
volume has been reduced to near 25
mL making certain the sample does
not boil After this treatment cool
the sample and filter to remove inso-
luble material that could clog the
nebulizer (See Note 4 ) Adjust the
volume to 100 mL and mix The sample
is now ready for analysis Concentra-
tions so determined shall be reported
as total
10 Procedure
101 Set up instrument with proper
operating parameters established m
6 2 The instrument must be allowed
to become thermally stable before be-
ginning This usually requires at least
30 mm of operation prior to calibra-
tion
102 Initiate appropriate operating
configuration of computer
103 Profile and calibrate instru-
ment according to instrument
manufacturer s recommended
procedures, using the typical mixed
calibration standard solutions
described in 7 4 Flush the system
with the calibration blank (751)
between each standard (See Note 7 )
(The use of the average intensity of
multiple exposures for both
standardization and sample analysis
has been found to reduce random
error)
NOTE 7 For boron concentrations
greater than 500 jjg/L extended flush
times of 1 to 2 mm may be required
104 Before beginning the sample
run reanalyze the highest mixed
calibration standard as if it were a
sample Concentration values obtained
should not deviate from the actual
values by more than ± 5 percent
(or the established control limits
whichever is lower) If they do, follow
the recommendations of the instru-
ment manufacturer to correct for this
condition
105 Begin the sample run flushing
the system with the calibration blank
solution (751) between each sample
(See Note 7 ) Analyze the instrument
check standard (761) and the calibra-
tion blank (751) each 10 samples
106 If it has been found that
method of standard addition are
required, the following procedure is
recommended
10 6 1 The standard addition tech-
nique (14 2) involves preparing new
standards in the sample matrix by
adding known amounts of standard to
one or more ahquots of the processed
sample solution This technique com-
pensates for a sample constituent that
enhances or depresses the analyte
signal thus producing a different slope
from that of the calibration standards
It will not correct for additive inter-
ference which causes a baseline shift
The simplest version of this technique
is the single-addition method The
procedure is as follows Two identical
ahquots of the sample solution, each
of volume Vx, are taken To the
first (labeled A) is added a small
volume Vs of a standard analyte
solution of concentration cs To the
second (labeled B) is added the same
volume Vs of the solvent The analy-
tical signals of A and B are measured
and corrected for nonanalyte signals
The unknown sample concentration
cx is calculated
cx = SBVscs
(SA - SB) Vx
where SA and SB are the analytical
signals (corrected for the blank) of
solutions A and B respectively Vs
and cs should be chosen so that SA
is roughly twice SB on the average It
is best if Vs is made much less than
Vx, and thus Cs is much greater than
cx, to avoid excess dilution of the
sample matrix If a separation or
concentration step is used, the
additions are best made first and
carried through the entire procedure
For the results from this technique to
be valid, the following limitations
must be taken into consideration
1 The analytical curve must be linear
2 The chemical form of the analyte
added must respond the same as the
analyte m the sample
Dec 1982
Metals-25
-------
3 The interference effect must be
constant over the working range of
concern
4 The signal must be corrected for
any additive interference
11. Calculation
11.1 Reagent blanks (7 5 2) should
be subtracted from all samples This is
particularly important for digested
samples requiring large quantities of
acids to complete the digestion
112 If dilutions were performed,
the appropriate factor must be applied
to sample values
113 Data should be rounded to the
thousandth place and all results
should be reported in mg/L up to
three significant figures
12. Quality Control
(Instrumental)
12.1 Check the instrument
standardization by analyzing
appropriate quality control check
standards as follow
12.1.1 Analyze an appropriate
Instrument check standard (761)
containing the elements of interest at
a frequency of 10% This check
standard is used to determine
Instrument drift If agreement is not
within ±5% of the expected values or
within the established control limits,
whichever is lower, the analysis is out
of control The analysis should be
terminated, the problem corrected,
and the instrument recalibrated
Analyze the calibration blank (751)
at a frequency of 10% The result
should be within the established
control limits of two standard devia-
tions of the mean value If not, repeat
the analysis two more times and
average the three results If the
average is not within the control limit,
terminate the analysis, correct the
problem and recalibrate the
instrument
1212 To verify interelement and
background correction factors analyze
the interference check sample (7 6 2)
at the beginning, end, and at periodic
Intervals throughout the sample run
Results should fall within the
established control limits of 1 5 times
the standard deviation of the mean
value If not. terminate the analysis,
correct the problem and recalibrate
the instrument
12.1,3 A quality control sample
(7 6 3) obtained from an outside
source must first be used for the
initial verification of the calibration
standards A fresh dilution of this
sample shall be anlayzed every week
thereafter to monitor their stability If
the results are not within ±5% of the
true value listed for the control
sample, prepare a new calibration
standard and recalibrate the
instrument If this does not correct the
problem, prepare a new stock
standard and a new calibration
standard and repeat the calibration
Precision and Accuracy
131 In an EPA round robin phase 1
study, seven laboratories applied the
ICP technique to acid-distilled water
matrices that had been dosed with
various metal concentrates Table 4
lists the true value, the mean reported
value and the mean % relative
standard deviation
References
1 Wmge RK VJ Peterson and
VA Fassel Inductively Coupled
Plasma-Atomic Emission
Spectroscopy Prominent Lines EPA-
600/4-79-017
2 Wmefordner J D Trace
Analysis Spectroscopic Methods for
Elements, Chemical Analysis Vol
46, pp 41 -42
3 Handbook for Analytical Quality
Control in Water and Wastewater
Laboratories, EPA-600/4-79-019
4 Garbarmo, J R and Taylor H E
An Inductively-Coupled Plasma
Atomic Emission Spectrometric
Method for Routine Water Quality
Testing Applied Spectroscopy 33,
No 3(1979)
5 Methods for Chemical Analysis of
Water and Wastes EPA-600/4-79-
020
6 Annual Book of ASTM Standards
Part 31
7 Carcinogens - Working With
Carcinogens Department of Health,
Education and Welfare Public Health
Service, Center for Disease Control,
National Institute for Occupational
Safety and Health Publication No 77-
206, Aug 1977
8 OSHA Safety and Health Stan-
dards General Industry (29 CFR
1910), Occupational Safety and Health
Administration OSHA 2206 (Revised
January 1976)
9 Safety in Academic Chemistry
Laboratories American Chemical So-
ciety Publication Committee on
Chemical Safety 3rd Edition 1979
Metals-26
Dec 1982
-------
Table 1 Recommended Wavelengths ' and Estimated Instrumental
Detection Limits
Element
Aluminum
Arsenic
Antimony
Barium
Beryllium
Boron
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Molybdenum
Nickel
Potassium
Selenium
Silica (SiOz)
Silver
Sodium _.
Thallium
Vanadium
Zinc
Wavelength, nm
308215
193 696
2O6 833
455 403
313042
249 773
226 502
317933
267716
228 616
324 754
259 940
220 353
279 079
257610
202 030
231 604
766491
196 026
288 158
328 068
588 995
19O 864
292 402
213856
Estimated detection
limit [ig/Lz
45
53
32
2
03
5
4
10
7
7
6
7
42
30
2
8
15
see3
75
58
7
29
40
8
2
overall acceptance Other wavelengths may be substituted if they can
provide the needed sensitivity and are treated with the same corrective
techniques for spectral interference (See 511)
zThe estimated instrumental detection limits as shown are taken from
'Inductively Coupled Plasma-Atomic Emission Spectroscopy-Promment
Lines EPA-600/4-79-017 They are given as a guide for an instrumental
limit The actual method detection limits are sample dependent and may vary
as the sample matrix varies
^Highly dependent on operating conditions and plasma position
'982 Metals-27
-------
Table 2 Analyte Concentration Equivalents (mg/L) Arising From Interferents at the 100 mg/L Level
Analvte Wavelength, nm Interferent
Aluminum
Antimony
Arsenic
Bsnum
Beryl/ium
Boron
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Molybdenum
Nickel
Selenium
Silicon
Sodium
Thallium
Vanadium
Zinc
308215
206 833
193 696
455403
313042
249 773
226502
317933
267 716
228 616
324 754
259 940
220 353
279 O79
257 610
202 030
231 604
196 026
288 158
588 995
190 864
292 402
213 856
Al Ca
— —
047 —
13 —
:
— —
004 —
— —
— —
_ _
— —
— —
077 —
— 002
0005 —
005 —
— —
023 —
— —
030 —
— —
Cr
—
29
044
_
•
008
—
003
—
—
0 11
001
—
—
—
007
—
—
005
—
Cu Fe
— —
— oos
— —
—
— —
— 032
— 003
— OO7
— 0003
— 0005
— OO03
— 0/3
— 0002
— 003
— —
— 003
— —
— —
— —
— 0005
014 —
Mg Mn
— 021
— —
—
— —
— —
— —
— —
007 O04
— 004
—
— —
— 0 72
— —
— 025
0002 —
— —
— —
— —
— —
— —
— —
— —
— —
Ni Ti
— —
— 25
~~ ~~
— —
— 004
~~ ~~
002 —
— 003
— —
0 03 0 75
— 005
~ ~~
— —
— 007
__
— —
— —
— — '
— —
— OOS
:
— 002
023 —
V
1 4
0 45
;*
1
— '
005
—
003
004
—
002
' —
0 72
—
007
:
__
—
Table 3. Interferent and Analyte Elemental Concen-
trations Used for Interference Measurements
in Table 2
Ana/ytes (mg/L)
Interferents
(mg/L)
Al
As
B
Ba
Be
Ca
Cd
Co
Cr
Cu
Fe
Mg
Mn
Mo
Na
Ni
Pb
Sb
Se
Si
TI
V
Zn
10
JO
1O
1
1
1
10
1
1
1
1
1
1
JO
10
10
JO
JO
JO
1
JO
1
10
Al
Ca
Cr
Cu
Fe
Mg
Mn
Ni
Ti
V
1000
10OO
200
200
1000
1000
200
200
200
200
Metals-28
Dec 1982
-------
Table 4
Element
Be
Mn
V
As
Cr
Cu
Fe
Al
Cd
Co
Ni
Pb
Zn
Se
ICP Precision and Accuracy Data
Sample # /
True
Value
M/L
750
350
750
200
150
250
600
700
50
500
250
250
200
40
Mean
Reported
Value
fjg/L
733
345
749
208
149
235
594
, 696
48
512
245
236
20 1
32
Mean
Percent
PSD
62
27
18
75
38
51
30
56
12
10
58
16
56
21 9
True
Value
Pff/L
20
15
70
22
JO
11
20
60
25
20
30
24
16
6
Sample #2
Mean
Reported
Value
H9/L
20
15
69
19
10
11
19
62
29
20
28
30
19
85
Mean
Percent
RSD
98
67
29
23
18
40
15
33
16
4 1
11
32
45
42
True
Value
V9/L
180
100
170
60
50
70
180,
160
14
120
60
80
80
10
Sample #3
Mean
Reported
Value
Pff/i-
176
99
169
63
50
67
178
161
13
108
55
80
82
85
-
.
Mean
Percent
RSD
52
33
1 1
17
33
79
60
13
16
21
14
14
94
83
Dec 1982
Meta/s-29
-------
ALUMINUM
Method 202.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01105
Dissolved 01106
Suspended 01107
Optimum Concentration Range: 5-50 mg/1 using a wavelength of 309 3 nm
Sensitivity: 1 mg/1
Detection Limit 0 1 mg/1
Preparation of Standard Solution
1 Stock Solution Carefully weigh 1 000 gram of aluminum metal (analytical reagent
grade) Add 15 ml of cone HC1 and 5 ml cone HNO3 to the metal, cover the beaker and
warm gently When solution is complete, transfer quantitatively to a 1 liter volumetric
flask and make up to volume with deiomzed distilled water 1 ml = 1 mg Al (1000 mg/1)
2 Potassium Chloride Solution Dissolve 95 g potassium chloride (KC1) in deiomzed
distilled water and make up to 1 liter
3 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared using the same type of acid and at
the same concentration as will result in the sample to be analyzed either directly or after
processing To each 100 ml of standard and sample alike add 2 0 ml potassium chloride
solution
Sample Preservation
1 For sample handling and preservation, see part 4,1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for the preparation of the sample as given in part 4 1 1 through 4 1 4 of
the Atomic Absorption Methods section of this manual have been found to be
satisfactory
Instrumental Parameters (General)
1 Aluminum hollow cathode lamp
2 Wavelength 309 3 nm
3 Fuel Acetylene
4 Oxidant Nitrous oxide
Approved for NPDES
Issued 1971
Editorial revision 1974 and 1978
202.1-1
-------
5. Type of flame Fuel rich
Analysis Procedure
1 For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Interferences
1 Aluminum is partially ionized in the nitrous oxide-acetylene flame This problem may be
controlled by the addition of an alkali metal (potassium, 1000 ug/ml) to both sample and
standard solutions
i *
Notes
1 The following lines may also be used
308 2 nm Relative Sensitivity 1
396 2 nm Relative Sensitivity 2
394 4 nm Relative Sensitivity 2 5
2 Data to be entered into STORET must be reported as ug/1
3 For concentrations of aluminum below 0 3 mg/1, the furnace procedure (Method 202 2)
is recommended
4 The Enochrome cyanme R colonmetnc method may also be used The optimum range
for this method lies between 20 and 300 ug/1 (Standard Methods, 14th Edition, p 171 )
In the absence of fluorides and complex phosphates, a detection limit of 6 ug/1 is
possible
Precision and Accuracy
1 An Intel-laboratory study on trace metal analyses by atomic absorption was conducted by
the Quality Assurance and Laboratory Evaluation Branch of EMSL Six synthetic
concentrates containing varying levels of aluminum, cadmium, chromium, copper, iron,
manganese, lead and zinc were added to natural water samples The statistical results for
aluminum were as follows
Number True values Mean Value Deviation Accuracy as
of Labs ug/liter ug/liter r ug/liter %Bias
38 1205 1281 299 63
38 1004 1003 391 -01
37 500 463 202 -74
37 625 582 272 -68
22 35 96 108 175
21 15 109 168 626
202 1-2
-------
ALUMINUM
Method 202.2 (Atomic Absorption, furnace technique)
STORET NO. Total 01105
Dissolved 01106
, , , Suspended 01107
tf
Optimum Concentration Range: 20-200 ug/1
Detection Limit: 3 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 0 5 % (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 0 5% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30 sec-125°C
2 Ashing Time and Temp 30sec-1300°C
3 Atomizing Time and Temp 10 sec-2700°C
4 Purge Gas Atmmosphere Argon
5 Wavelength 309 3 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer f
Analysis Procedure
1 For the analysis procedure and the caculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Approved for NPDES
Issued 1978
202 2-1
-------
Notes
1. The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and non-pyrolytic
graphite
2 Background correction may be required if the sample contains high dissolved solids
3 It has been reported that chloride ion and that nitrogen used as a purge gas suppress the
aluminum signal Therefore the use of halide acids and nitrogen as a purge gas should be
avoided
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
6 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 Precision and accuracy data are not available at this time
202 2-2
-------
ANTIMONY
Method 204.1 (Atomic absorption, direct aspiration)
STORET NO. Total 01097
Dissolved 01095
Suspended 01096
Optimum Concentration Range: 1-40 mg/1 using a wavelength of 217 6 nm
Sensitivity: 0 5 mg/1
Detection Limit: 0 2 mg/1
Preparation of Standard Solution
1 Stock Solution Carefully weigh 2 7426 g of antimony potassium tartrate
K(SbO)C4H4O6« ^H2O (analytical reagent grade) and dissolve in deiomzed distilled
water Dilute to 1 liter with deiomzed distilled water 1 ml = 1 mg Sb (1000 mg//l)
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared using the same type of acid and at
the same concentration as will result in the sample to be analyzed either directly or after
processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 through 414 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
Instrumental Parameters (General)
1 Antimony hollow cathode lamp
2 Wavelength 2176 nm
3 Fuel Acetylene
4 Oxidant Air
5 Type of flame Fuel lean
Analysis Procedure
1 For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Approved for NPDES
Issued 1974
Editorial revision 1978
204 1-1
-------
Interferences
1. In the presence of lead (1000 mg/1), a spectral interference may occur at the 217 6 nm
resonance line In this case the 2311 nm antimony line should be used
2 Increasing acid concentrations decrease antimony absorption To avoid this effect, the
acid concentration m the samples and in the standards should be matched
Notes
1 Data to be entered into STORET must be reported as ug/1
2 For concentrations of antimony below 0 35 mg/1, the furnace procedure (Method 204 2)
is recommended
Precision and Accuracy
1 In a single laboratory (EMSL), using a mixed industrial-domestic waste effluent at
concentrations of 5 0 and 15 mg Sb/1, the standard deviations were ±0 08 and ±0 1,
respectively Recoveries at these levels were 96% and 97%, respectively
204 1-2
-------
ANTIMONY
Method 204.2 (Atomic Absorption, furnace technique)
STORET NO. Total 01097
Dissolved 01095
Suspended 01096
Optimum Concentration Range* 20-300 ug/1
Detection Limit: 3 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 0 2% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 thru 4 1 3 of the
Atomic Absorption Methods section of this manual should be followed including the
addition of sufficient 1 1 HC1 to dissolve the digested residue for the analysis of
suspended or total antimony The sample solutions used for analysis should contain 2%
(v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30 sec-125°C
2 Ashing Time and Temp 30sec-800°C
3 Atomizing Time and Temp 10 sec-2700°C
4 Purge Gas Atmosphere Argon
5 Wavelength 217 6 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Approved for NPDES
Issued 1978
204 2-1
-------
Notes
1 1 he above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and non-pyrolytic
graphite Smaller size furnace devices or those employing faster rates of atomization can
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings
2 The use of background correction is recommended
3 Nitrogen may also be used as the purge gas
4 If chloride concentration presents a matrix problem or causes a loss previous to
atomization, add an excess of 5 mg of ammonium nitrate to the furnace and ash using a
ramp accessory or with incremental steps until the recommended ashing temperature is
reached
5 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
6 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
7 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 Precision and accuracy data are not available at this time
204 2-2
-------
ARSENIC
Method 206.2 (Atomic Absorption, furnace technique)
STORET NO. Total 01002
Dissolved 01000
Suspended 01001
Optimum Concentration Range: 5-100 ug/1
Detection Limit: 1 ug/1
Preparation of Standard Solution
1 Stock solution Dissolve 1 320 g of arsenic tnoxide, As203 (analytical reagent grade) in
100 ml of deiomzed distilled water containing 4 g NaOH Acidify the solution with 20 ml
cone HNO3 and dilute to 1 liter 1 ml = 1 mg As (1000 mg/1)
2 Nickel Nitrate Solution, 5% Dissolve 24 780 g of ACS reagent grade Ni(NO3)2«6H2O in
deiomzed distilled water and make up to 100ml
3 Nickel Nitrate Solution, 1% Dilute 20 ml of the 5% nickel nitrate to 100 ml with
deiomzed distilled water
4 Working Arsenic Solution Prepare dilutions of the stock solution to be used as
calibration standards at the time of analysis Withdraw appropriate ahquots of the stock
solution, add 1 ml of cone HNO3, 2ml of 30% H2O2 and 2ml of the 5% nickel nitrate
solution Dilute to 100 ml with deiomzed distilled water
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Transfer 100 ml of well-mixed sample to a 250 ml Griffin beaker, add 2 ml of 30% H2O2
and sufficient cone HNO3 to result in an acid concentration of 1 %(v/v) Heat for 1 hour
at 95°C or until the volume is slightly less than 50 ml
2 Cool and bring back to 50 ml with deiomzed distilled water
3 Pipet 5 ml of this digested solution into a 10-ml volumetric flask, add 1 ml of the 1%
nickel nitrate solution and dilute to 10 ml with deiomzed distilled water The sample is
now ready for injection into the furnace
Approved for NPDES and SDWA
Issued 1978
206 2-1
-------
NOTE: If solubilization or digestion is not required, adjust the HNO3 concentration of
the sample to 1% (v/v) and add 2 ml of 30%H2O2 and 2 ml of 5% nickel nitrate to each
100 ml of sample The volume of the calibration standard should be adjusted with
deiomzed distilled water to match the volume change of the sample
Instrument Parameters (General)
1. Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-1100°C
3 Atomizing Time and Temp 10sec-2700°C
4 Purge Gas Atmosphere Argon
5. Wavelength 193 7 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
»
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Notes
1 The above concentration values and instrument conditions are for a Perkin-Elmer HGA-
2100, based on the use of a 20 ul injection, purge gas interrupt and non-pyrolytic
graphite Smaller size furnace devices or those employing faster rates of atomization can
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings
2 The use of background correction is recommended
3 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
4 If method of standard addition is required, follow the procedure given earlier m part 8 5
of the Atomic Absorption Methods section of this manual
5. For quality control requirements and optional recommendations for use in drinking
water analyses, see part 10 of the Atomic Absorption Methods section of this manual
6. Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 In a single laboratory (EMSL), using a mixed industrial-domestic waste effluent
containing 15 ug/1 and spiked with concentrations of 2, 10 and 25 ug/1, recoveries of
85%, 90% and 88% were obtained respectively The relative standard deviation at these
concentrations levels were ±88%, ±& 2%, ±5 4% and ±8 7%, respectively
2 In a single laboratory (EMSL), using Cincinnati, Ohio tap water spiked at concentrations
of 20, 50 and 100 ug As/1, the standard deviations were ±07, ±11 and ±16
respectively Recoveries at these levels were 105%, 106% and 101%, respectively
206 2-2
-------
ARSENIC
Method 206.3 (Atomic Absorption—gaseous hydride)
STORET NO. Total 01002
Dissolved 01000
Suspended 01001
Scope and Application
1 1 The gaseous hydride method determines inorganic arsenic when present in
concentrations at or above 2 ug/1 The method is applicable to drinking water and most
fresh and saline waters in the absence of high concentrations of chromium, cobalt,
copper, mercury, molybdenum, nickel and silver
Summary of Method
2 1 Arsenic in the sample is first reduced to the tnvalent form using SnCl2 and converted to
arsine, AsH3, using zinc metal The gaseous hydride is swept into an argon-hydrogen
flame of an atomic absorption spectrophotometer The working range of the method is
2-20 ug/1 The 193 7 nm wavelength line is used
Comments
3 1 In analyzing drinking water and most surface and ground waters, interferences are rarely
encountered Industrial waste samples should be spiked with a known amount of arsenic
to establish adequate recovery
3 2 Organic forms of arsenic must be converted to inorganic compounds and organic matter
must be oxidized before beginning the analysis The oxidation procedure given in
Method 206 5 (Standard Methods, 14th Edition, Method 404B, p 285, Procedure 4 a)
has been found suitable
3 3 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
3 4 For quality control requirements and optional recommendations for use in drinking
water analyses, see part 10 of the Atomic Absorption Methods section of this manual
3 5 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
4 1 Ten replicate solutions of o-arsemhc acid at the 5,10 and 20 ug/1 level were analyzed by
a single laboratory Standard deviations were ±03, ±09 and ±1 1 with recoveries of 94,
93 and 85%, respectively (Caldwell, J S, Lishka, R J, and McFarren, E F,
"Evaluation of a Low Cost Arsenic and Selenium Determination at Microgram per Liter
Levels", JAWWA , vol 65, p 731, Nov , 1973 )
Approved for NPDES and SDWA
Issued 1974
2063-1
-------
5. References
5 1, Except for the perchloric acid step, the procedure to be used for this determination is
found m Standard Methods for the Examination of Water and Wastewater, 14th
Edition, p!59, Method 301 A(VII),(1975)
206 3-2
-------
ARSENIC ,
o i
Method 206.4 (Spectrophotometric-SDDC)
STORET NO. 01002
Inorganic, Dissolved 00095
Inorganic, Total 00997
Inorganic, Suspended 00996
1 Scope and Application
1 1 The silver diethyldithiocarbamate method determines inorganic arsenic when present m
concentrations at or above 10 ug/1 The method is applicable to drinking water and most
fresh and saline waters in the absence of high concentrations of chromium, cobalt,
copper, mercury, molybdenum, nickel, and silver Domestic and industrial wastes may
also be analyzed after digestion (see 3 3)
1 2 Difficulties may be encountered with certain industrial waste materials containing
volatile substances High sulfur content of wastes may exceed removal capacity of the
lead acetate scrubber
2 Summary of Method
2 1 Arsenic in the sample is reduced to arsme, AsH3, in acid solution in a hydrogen
generator The arsme is passed through a scrubber to remove sulfide and is absorbed in a
solution of silver diethyldithiocarbamate dissolved in pyndine The red complex thus
formed is measured in a spectrophotometer at 535 nm
3 Comments
31 In analyzing drinking water and most surface and ground waters, interferences are rarely
encountered Industrial waste samples should be spiked with a known amount of arsenic
to establish adequate recovery
32 It is essential that the system be airtight during evolution of the arsme, to avoid losses
33 If concentration of the sample and/or oxidation of any organic matter is required, refer
to Method 206 5 [Standard Methods, 14th Edition, Method 404B, p 284, Procedure 4 a
(1975)] For sample handling and preservation, see part 4 1 of the Atomic Absorption
Methods section of this manual
331 Since nitric acid gives a negative interference in this test, use sulfunc acid as a
preservative if only inorganic arsenic is being measured
3 4 1-Ephedrme in chloroform has been found to be a suitable solvent for silver
diethyldithiocarbamate if the analyst finds the odor of pyndine objectionable [Anal
Chem 45, 1786 (1973)]
3 5 For quality control requirements and optional recommendations for use in drinking
water analyses, see part 10 of the Atomic Absorption Methods section of this manual
Approved for NPDES and SDWA
Issued 1971
Editorial revision 1974
206 4-1
-------
4. Precision and Accuracy
41 In a round-robm study reported by Standard Methods a synthetic unknown sample
containing 40 ug/1, as As, with other metals was analyzed in 46 laboratories Relative
standard deviation was ±138% and relative error was 0%
5. Reference
5 1 The procedure to be used for this determination is found in
Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 283,
Method 404A (1975)
206 4-2
-------
ARSENIC
Method 206.5 (Sample Digestion Prior to Total Arsenic
Analysis by Silver Diethyldithiocarbamate or Hydride
Procedures)
Scope and Application
1 1 Both the silver diethyldithiocarbamate spectrophotometric method and the AA hydride
procedure measure inorganic arsenic Therefore, if either of these procedures are being
employed for the purpose of measuring total arsenic (inorganic plus organic), all
organically bound arsenic must first be converted to an inorganic form prior to the
analytical determination This may be accomplished with H2SO4-HNO3
Procedure
21 To a suitable sample containing from 2 to 30 ug of arsenic, add 7 ml (1 +1) H2SO4 and 5
ml cone HNO3 Evaporate the sample to SO3 fumes Caution If the sample chars, stop
the digestion immediately, cool and add additional cone HNO3 Continue digestion
adding additional cone HNO3 as necessary
22 If the sample remains colorless, or straw-yellow during evolution of SO3 fumes, the
digestion is complete
2 3 Cool the digested sample, add about 25 ml distilled water, and again evaporate to SO3
fumes to expel oxides of nitrogen
2 4 The sample is now ready for analysis using either the hydride or spectrophotometric
procedure
Interferences
3 1 All traces of nitric acid must be removed before either the spectrophotometric or the
hydride procedures are applied Oxides of nitrogen should be expelled by taking the
sample to fumes of SO3
Notes
4 1 The digestion step may be carried out in a flask on a hot-plate or in a Kjeldahl apparatus
This digestion step may also be used, in effect, to concentrate the sample, inasmuch as
any size volume may be processed
Bibliography
Standard Methods for the Examination of Water and Wastewater, p285, method 404B, step 4a,
14th Edition (1975)
Approved for NPDES and SDWA
Issued 1978
206 5-1
-------
BARIUM
Method 208.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01007
Dissolved 01005
Suspended 01006
Optimum Concentration Range; 1-20 mg/1 using a wavelength of 553 6 nm
Sensitivity: 0 4 mg/1
Detection Limit: 0 1 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 1 7787 g barium chloride (BaCl2«2H2O, analytical reagent
grade) in deiomzed distilled water and dilute to 1 liter 1 ml = 1 mg Ba (1000 mg/1)
2 Potassium chloride solution Dissolve 95 g potassium chloride, KC1, in deiomzed
distilled water and make up to 1 liter
3 Prepare dilutions of the stock barium solution to be used as calibration standards at the
time of analysis To each 100 ml of standard and sample alike add 2 0 ml potassium
chloride solution The calibration standards should be prepared using the same type of
acid and the same concentration as will result in the sample to be analyzed either directly
or after processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 through 414 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
Instrumental Parameters (General)
1 Barium hollow cathode lamp
2 Wavelength 553 6 nm
3 Fuel Acetylene
4 Oxidant Nitrous oxide
5 Type of flame Fuel rich
Approved for NPDES and SDWA
Issued 1974
208 1-1
-------
Analysis Procedure
1 For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Interferences
1 The use of a nitrous oxide-acetylene flame virtually eliminates chemical interference,
however, barium is easily ionized in this flame and potassium must be added (1000 mg/1)
to standards and samples alike to control this effect
2 If the nitrous oxide flame is not available and acetylene-air is used, phosphate, silicon and
aluminum will severely depress the barium absorbance This may be overcome by the
addition of 2000 mg/1 lanthanum
Notes
1 Data to be entered into STORET must be reported as ug/1
2 For concentrations of barium below 0 2 mg/1, the furnace procedure (Method 208 2) is
recommended '
3 For quality control requirements and optional recommendations for use in drinking
water analyses, see part 10 of the Atomic Absorption Methods section of this manual
Precision and Accuracy
1 In a single laboratory (EMSL), using a mixed industrial-domestic waste effluent at
concentrations of 040 and 20 mg Ba/1, the standard deviations were ±0043
and ±0 13, respectively Recovereis at these levels were 94% and 113%, respectively
2 In a round-robin study reported by Standard Methods (13th Edition, p215, method
129A, 1971), three synthetic samples containing barium were analyzed by 13
laboratories At concentrations of 500, 1000 and 5000 ug Ba/1, the reported standard
deviations were ±50, ±89 and ±185 ug, respectively The relative error at these
concentrations was 8 6%, 2 7% and 1 4%, respectively
208 1-2
-------
BARIUM
Method 208.2 (Atomic Absorption, furnace technique)
STORET NO. 01007
Dissolved 01005
Suspended 01006
Optimum Concentration Range: 10-200 ug/1
Detection Limit: 2 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to used for "standard additions"
3 The calibration standard should be diluted to contain 0 5 % (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 0 5% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-1200°C
3 Atomizing Time and Temp 10 sec-2800°C
4 Purge Gas Atmosphere Argon
5 Wavelength 553 6 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and pyrolytic
graphite
Approved for NPDES and SDWA
Issued 1978
208 2-1
-------
2 The use of hahde acid should be avoided
3 Because of possible chemical interaction, nitrogen should not be used as a purge gas
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
6 For quality control requirements and optional recommendations for use in drinking
water analyses, see part 10 of the Atomic Absorption Methods section of this manual
7 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1. In a single laboratory (EMSL), using Cincinnati, Ohio tap water spiked at concentrations
of 500 and 1000 ug Ba/1, the standard deviations were ±25 and ±2 2 ug, respectively
Recoveries at these levels were 96% and 102%, respectively A dilution of 1 10 was
required to bring the spikes within the analytical range of the method
2082-2
-------
BERYLLIUM
Methods 210.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01012
Dissolved 01010
Suspended 01011
Optimum Concentration Range: 0 05-2 mg/1 using a wavelength of 234 9 nm
Sensitivity: 0 025 mg/1
Detection Limit: 0 005 mg/1
Preparation of Standard Solution
1 Stock solution Dissolve 19 6558 g beryllium sulfate, BeSO«4H2O, in deionized
distilled water containing 2 ml cone nitric acid and dilute to 1 liter 1 ml = 1 mg Be
(1000 mg/1)
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared using the same type of acid and at
the same concentration as will result in the sample to be analyzed either directly or after
processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 through 414 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
Instrumental Parameters (General)
1 Beryllium hollow cathode lamp
2 Wavelength 234 9 nm
3 Fuel Acetylene
4 Oxidant Nitrous oxide
5 Type of flame Fuel rich
Analysis Procedure
1 For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Approved for NPDES
Issued 1974
210 1-1
-------
Interferences
1 Sodium and silicon at concentrations m excess of 1000 mg/1 have been found to severely
depress the beryllium absorbance
2 Bicarbonate ion is reported to interfere, however, its effect is eliminated when samples
are acidified to a pH of 1 5
3. Aluminum at concentrations of 500 ug/1 is reported to depress the sensitivity of
beryllium [Spectrochim Acta 22,1325 (1966)]
Notes
1. Data to be entered into STORET must be reported as ug/1
2 The "aluminon colonmetnc method" may also be used (Standard Methods, 14th
Edition, p 177) The minimum detectable concentration by this method is 5 ug/1
3 For concentrations of beryllium below 0 02 mg/1, the furnace procedure (Method 2102)
is recommended
Precision and Accuracy
1. In a single laboratory (EMSL), using a mixed industrial-domestic waste effluent at
concentrations of 0 01, 0 05 and 0 25 mg Be/1, the standard deviations were ±0 001,
±0 001 and ±0 002, respectively Recoveries at these levels were 100%, 98% and 97%,
respectively
210 1-2
-------
BERYLLIUM
i I
Method 210.2 (Atomic Absorption, furnace technique)
STORET NO. 01012
Dissolved 01010
Suspended 01011
Optimum Concentration Range: 1-30 ug/1
Detection Limit 0 2 ug/1
Preparation of Standard Solution
1 Stock solution- Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 05% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
1 section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 05% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-1000°C
3 Atomizing Time and Temp 10 sec-2800°C
4 Purge Gas Atmosphere Argon
5 Wavelength 234 9 nm
6 The operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation see "Furnace Procedure" part 9 3 of the
Atomic Absorption methods section of this manual
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and non-pyrolytic
graphite Smaller size furnace devices or those employing faster rates of atomization can
Approved for NPDES
Issued 1978
210 2-1
-------
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings
2. The use of background correction is recommended
3 Because of possible chemical interaction and reported lower sensitivity, nitrogen should
not be used as the purge gas
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
6 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 Precision and Accuracy data are not available at this time
210 2-2
-------
BORON
Method 212.3 (Colorimetric, Curcumin)
STORET NO. Total 01022
Dissolved 01020
Suspended 01021
Scope and Application
1 1 This colonmetnc method finds maximum utility for waters whose boron content is
below 1 mg/1
1 2 The optimum range of the method on undiluted or unconcentrated samples is 0 1-1 0
mg/1 of boron
1 3 This method is applicable to drinking, and surface waters, domestic and industrial
wastes
Summary of Method
2 1 When a sample of water containing boron is acidified and evaporated in the presence of
curcumm, a red-colored product called rosocyanine is formed The rosocyamne is taken
up in a suitable solvent, and the red color is compared with standards photometrically
Comments
3 1 Nitrate nitrogen concentrations above 20 mg/1 interfere
3 2 Significantly high results are possible when the total of calcium and magnesium hardness
exceeds 100 mg/1 as CaCO3 Passing the sample through a cation exchange resin
eliminates this problem
3 3 Close control of such variables as volumes and concentrations of reagents, as well as time
and temperature of drying, must be exercised for maximum accuracy
3 4 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
4 1 A synthetic sample prepared by the Analytical Reference Service, PHS, containing 240
ug/1 B, 40 ug/1 As, 250 ug/1 Be, 20 ug/1 Se, and 6 ug/1 V in distilled water, was
analyzed by the curcumm method with a relative standard deviation of 22 8% and a
relative error of 0% in 30 laboratories
Reference
5 1 The procedure to be used for this determination is found in
Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 287,
Method 405 A (1975)
Approved for NPDES
Issued 1974
2123-1
-------
CADMIUM
Method 213.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01027
Dissolved 01025
Suspended 01026
Optimum Concentration Range: 0 05-2 mg/1 using a wavelength of 228 8 nm
Sensitivity: 0 025 mg/1
Detection Limit. 0 005 mg/1
Preparation of Standard Solution
1 Stock Solution Carefully weigh 2 282 g of cadmium sulfate (3CdSO4»8H2O, analytical
reagent grade) and dissolve in deionized distilled water make up to 1 liter with
deionized distilled water 1 ml = 1 mg Cd (1000 mg/1)
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared using the same type of acid and at
the same concentration as will result in the sample to be analyzed either directly or after
processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 4 1 1 through 414 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
Instrumental Parameters (General)
1 Cadmium hollow cathode lamp
2 Wavelength 228 8 nm
3 Fuel Acetylene
4 Oxidant Air
5 Type of flame Oxidizing
Analysis Procedure
1 For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Approved for NPDES and SDWA
Issued 1971
Editorial revision 1974
213 1-1
-------
Notes
1 For levels of cadmium below 20 ug/1, either the Special Extraction Procedure given in
Part 9 2 of the Atomic Absorption methods section as the furnace technique, Method
213 2 is recommended
2 Data to be entered into STORET must be reported as\ug/l
3 For quality control requirements and optional recommendations for use in drinking
water analyses, see part 10 of the Atomic Absorption Methods section of this manual
Precision and Accuracy
1 An mterlaboratory study on trace metal analyses by atomic absorption was conducted by
the Quality Assurance and Laboratory Evaluation Branch of EMSL Six synthetic
concentrates containing varying levels of aluminum, cadmium, chromium, copper, iron,
manganese, lead and zinc were added to natural water samples The statistical results for
cadmium were as follows
Standard
Number True Values Mean Value Deviation Accuracy as
of Labs ug/liter ug/liter ug/liter % Bias
74 71 70 21 -22
73 78 74 18 -5 /
63 14 168 110 198
68 18 183 103 19
55 14 33 50 135
51 28 29 28 47
213 1-2
-------
CADMIUM
Method 213.2 (Atomic Absorption, furnace technique)
STORET NO. 01027
Dissolved 01025
Suspended 01026
Optimum Concentration Range: 05-10 ug/1
Detection Limit: 0 1 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Ammonium Phosphate solution (40%) Dissolve 40 grams of ammonium phosphate,
(NH4)2HPO4 (analytical reagent grade) in deiomzed distilled water and dilute to 100 ml
3 Prepare dilutions of the stock cadmium solution to be used as calibration standards at the
time of analysis To each 100 ml of standard and sample alike add 2 0 ml of the
ammonium phosphate solution The calibration standards should be prepared to contain
0 5% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 05% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30 sec-125°C
2 Ashing Time and Temp 30 sec-500°C
3 Atomizing Time and Temp 10 sec-1900°C
4 Purge Gas Atmosphere Argon
5 Wavelength 228 8 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Approved for NPDES and SDWA
Issued 1978
213 2-1
-------
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and non-pyrolytic
graphite Smaller size furnace devices or those employing faster rates of atomization can
be operated using lower atomization temperatures for shorter tune periods than the
above recommended settings
2 The use of background correction is recommended
3. Contamination from the work area is critical in cadmium analysis Use of pipet tips
j ill '* I
which are free of cadmium is of particular importance (See part 5 2 9 of the Atomic
Absorption Methods section of this manual)
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 52 I of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
6 For quality control requirements and optional recommendations for use in drinking
water analyses, see part 10 of the Atomic Absorption Methods section of this manual
7 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 In a single laboratory (EMSL), using Cincinnati, Ohio tap water spiked at concentrations
of 2 5, 50 and 10 0 ug Cd/1, the standard deviations were ±0 10, ±016 and ±0 33,
respectively Recoveries at these levels were 96%, 99% and 98%, respectively
213 2-2
-------
CALCIUM
s
Method 215.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 00916
Dissolved 00915
Optimum Concentration Range: 0 2-7 mg/i using a wavelength,of 422 7 nm
Sensitivity: 0 08 mg/1
Detection Limit: 001 mg/1
Preparation of Standard Solution
, 1 Stock Solution Suspend 1 250 g of CaCO3 (analytical reagent grade), dried at 180°C for 1
hour before weighing, in deiomzed distilled water and dissolve cautiously with a
minimum of dilute HC1 Dilute to 1000 ml with, deiomzed distilled water 1 ml = 05
mgCa (500 mg/1)
2 Lanthanum chloride solution Dissolve 29 g of La2O3, slowly and in small portions, in
250 ml cone HC1 (Caution Reaction is violent) and dilute to 500 ml with deiomzed
distilled water
3 Prepare dilutions of the stock calcium solutions to be used as calibration standards at the
time of analysis To each 10 ml volume of calibration standard and sample alike add 1 0
ml of the lanthanum chloride solution, i e, 20 ml of standard or sample + 2 ml LaCl3 =
22ml
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 For the analysis of total calcium in domestic and industrial effluents, the procedures for
the determination of total metals as given in parts 413 and 4 1 4 of the Atomic
Absorption Methods section of this manual have been found to be satisfactory
2 For ambient waters, a representative aliquot of a well-mixed sample may be used directly
for analysis If suspended solids are present in sufficient amounts to clog the nebulizer,
the sample may be allowed to settle and the supernatant liquid analyzed directly
Instrumental Parameters (General)
1 Calcium hollow cathode lamp
2 Wavelength 422 7 nm
Approved for NPDES
Issued 1971
Editorial revision 1974
215 1-1
-------
3 Fuel Acetylene
4. Oxidant Air
5 Type of flame Reducing
Analysis Procedure
1. For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Notes
1 Phosphate, sulfate and aluminum interfere but are masked by the addition of lanthanum
Since low calcium values result if the pH of the sample is above 7, both standards and
samples are prepared in dilute hydrochloric acid solution Concentrations of magnesium
greater than 1000 mg/1 also cause low calcium values Concentrations of up to 500 mg/1
each of sodium, potassium and nitrate cause no interference
2 Anionic chemical interferences can be expected if lanthanum is not used in samples and
standards
3 The nitrous oxide-acetylene flame will provide two to five times greater sensitivity and
freedom from chemical interferences lomzation interferences should be controlled by
adding a large amount of alkali to the sample and standards The analysis appears to be
free from chemical suppressions in the nitrous oxide-acetylene flame (Atomic
Absorption Newsletter 14,29 [1975])
4 The 239 9 nm line may also be used This line has a relative sensitivity of 120
5. Data to be entered into STORET must be reported as mg/1
6 The EDTA titnmetnc method may also be used (Standard Methods, 14th Edition, p
189)
Precision and Accuracy
1 In a single laboratory (EMSL), using distilled water spiked at concentrations of 9 0 and
36 ragCa/1, the standard deviations were ±0 3 and ±0 6, respectively Recoveries at
both these levels were 99%
215 1-2
-------
CALCIUM
Method 215.2 (Titrimetric, EDTA)
STORET NO. Calcium (mg/1 CaCO3) 00910
Calcium, Total (mg/1 Ca) 00916
Scope and Application
1 1 This method is applicable to drinking and surface waters, domestic and industrial wastes
1 2 The lower detection limit of this method is approximately 0 5 mg/1 as CaCO3, the upper
limit can be extended to all concentrations by sample dilution It is recommended that a
sample aliquot containing not more than 25 mg CaCO3 be used
Summary of Method
2 1 Calcium ion is sequestered upon the addition of disodium dihydrogen ethylenediamme
tetraacetate (EDTA) The titration end point is detected by means of an indicator which
combines with calcium only
Interferences
3 1 Strontium and barium interfere and alkalinity in excess of 30 mg/1 may cause an
indistinct end point Magnesium interference is reduced or eliminated by raising the pH
between 12-13 to precipitate magnesium hydroxide
Apparatus
4 1 Routine laboratory titnmetnc glassware
Reagents
5 1 Sodium hydroxide, NaOH, 1 N
5 2 Indicators
521 Many indicators are available, both laboratory prepared and commercial, and may
be used Two are described here
522 Murexide (ammonium purpurate) indicator This changes from pink to purple
Dissolve 150 mg of the dye in 100 g absolute ethylene, glycol If a dry powder is
preferred mix 200 mg murexide with 100 g solid NaCl and grind to 40 to 50 mesh
Titrate immediately after adding indicator because it is unstable under alkaline
conditions
523 Eriochrome Blue Black R (sodium-l-(2-hydroxy-l-naphthylazo)-2-naphthol-4-
sulfonic acid) indicator This changes from red through purple to bluish purple to a
pure blue without any trace of red or purple tint The pH of some waters must be
raised to 14 (rather than 12-13) by the use of 8 N NaOH in order to get a good
color change Grind in a mortar 200 mg powdered dye and 100 g solid NaCl to 40
to 50 mesh Store in tightly stoppered bottle Use 0 2 g of this mixture for titration
Approved for NPDES
Issued 1974
Editorial revision 1978
215 2-1
-------
5 3 Standard EDTA titrant, 0 02 N Place 3 723 g analytical reagent grade disodium
ethylenediamme tetraacetate dihydrate, Na2H2C10H12O8N2»2 H2O in a 1 liter volumetric
flask and dilute to the mark with distilled water Check with standard calcium solution
(5 3 1) by titration (5 3 5) Store in polyethylene Check periodically because of gradual
deterioration
531 Standard calcium solution, 0 02 N Place 1 000 g anhydrous calcium carbonate
(pnmai y standard low in heavy metals, alkalies and magnesium) in a 500 ml
flask Add, a little at a time 1 +1 HC1 (5 3 2) until all of the CaCO3 has dissolved
Add 200 ml distilled water Boil for a few minutes to expel CO2 Cool Add a few
drops of methyl red indicator (533) and adjust to intermediate orange color by
adding 3N NH4OH (5 3 4) or 1 +1 HC1 (5 3 2) as required Quantitatively
transfer to a 1 liter volumetric flask and dilute to mark with distilled water
532 Hydrochloric acid solution, 1 + 1
5.3 3 Methyl red indicator Dissolve 0 10 g methyl red in distilled water in a 100 ml
volumetric flask and dilute to mark
534 Ammonium hydroxide solution, 3 N
535 Standardization titration procedure Place 10 ml standard calcium solution
(5 3 1) in a vessel containing about 50 ml distilled water Addl ml buffer solution
(5 3 6) Add 1-2 drops indicator (5 3 7) or small scoop of dry indicator (5 3 7)
Titrate slowly with continuous stirring until the last reddish tinge disappears,
adding last few drops at 3-5 second intervals At end point the color is blue Total
titration duration should be < 5 minutes from the time of buffer addition
62
N of EDTA =
ml EDTA
536 Buffer solution Dissolve 16 9 g ammonium chloride in 143 ml cone ammonium
hydroxide in a 250 ml volumetric flask Add 1 25 g of magnesium salt of EDTA
(5 3 8) and dilute to the mark with distilled water Store in tightly stoppered plastic
bottle
537 Indicator Commercially available Enochrome Black T is used in one of the three
methods described All gradually detenorate
5371 Mix 0 5 g dye with 4 5 g hydroxylamme hydrochlonde Dissolve in 100
ml of 95% ethanol or isopropanol
5372 Place 0 5-1 0 g dye in 100 g of tnethanolamine or 2-methoxyethanol
5373 Mix 0 5 g dye and 100 g NaCl for dry formulation
538 EDTA Magnesium Salt Commercially available
Procedure
61 Pretreatment
611 For drinking waters, surface waters, saline waters, and dilutions thereof, no
pretreatment steps are necessary Proceed to 6 2
612 For most wastewaters and highly polluted waters, the sample must be digested as
given m the Atomic Absorption Methods section of this manual, paragraphs 413
and 414 Following this digestion, proceed to 6 2
6 2 Sample Preparation
621 The calcium content of the 50 ml aliquot to be titrated should be 5-10 mg,
therefore dilution should be used for high calcium concentrations
215 2-2
-------
622 If the alkalinity is > 300 mg/1 CaCO3 and cannot be reduced by dilution because
of low calcium concentration, the alkalinity must be decreased by acidifying,
boiling one minute and cooling
6 3 Titration
631 Add 2 0 ml NaOH solution (5 1), or a volume sufficient to produce pH 12 to 13, to
50 ml of sample
632 Stir Add 0 1 to 0 2 g indicator (5 2 2, or 5 2 3) or 1-2 drops if indicator solution is
used
633 Immediately titrate with continuous stirring Check to see that no further color
change occurs when using murexide (5 2 2) by adding 1 to 2 more drops of titrant
after recording millihters of titrant at first judged end point
7 Calculations
7 1 Total calcium
., _ A x N x 20,040
m§/1Ca= ml of sample
where
A = ml titrant
N = Normality of EDT A solution
7 2 Calcium hardness
mg/lCaC03= Ax NX 50,000
ml of sample
where A and N are the same as in 7 1
8 Precision and Accuracy
81 A synthetic unknown sample containing 108 mg/1 Ca, 82 mg/1 Mg, 3 1 mg/1 K, 19 9
mg/1 Na, 241 mg/1 chloride, 1 1 mg/1 nitrate N, 250 ug/l nitrite N, 259 mg/1 sulfate,
and 42 5 mg/1 total alkalinity in distilled water was determined by this method with a
relative standard deviation of 9 2% and a relative error of 19% in 44 laboratories
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 189,
Method 306C (1975)
2 Annual Book of ASTM Standards, Part 31, "Water", Standard D511-76, Method B, p 253
(1976)
215 2-3
-------
CHROMIUM
Method 218.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01034
Dissolved 01030
Suspended 01031
Optimum Concentration Range: 0 5-10 mg/1 using a wavelength of 357 9 nm
Sensitivity: 0 25 mg/1
Detection Limit: 0 05 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 1 923 g of chromium tnoxide (CrO3, reagent grade) in deiomzed
distilled water When solution is complete, acidify with redistilled HNO3 and dilute to 1
liter with deiomzed distilled water 1ml = 1 mg Cr (1000 mg/1)
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared using the same type of acid and at
the same concentration as will result in the sample to be analyzed either directly or after
processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 thru 4 1 4 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
Instrumental Parameters (General)
1 Chromium hollow cathode lamp
2 Wavelength 357 9 nm
3 Fuel Acetylene
4 Oxidant Nitrous oxide
5 Type of flame Fuel rich
Analysis Procedure
1 For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Approved for NPDES and SDWA
Issued 1971
Editorial revision 1974 and 1978
218 1-1
-------
Notes
1 The following wavelengths may also be used
359 3 nm Relative Sensitivity 1 4
425 4 nm Relative Sensitivity 2
427 5 nm Relative Sensitivity 3
428 9 nm Relative Sensitivity 4
2 The fuel nch air-acetylene flame provides greater sensitivity but is subject to chemical
and matrix interference from iron, nickel, and other metals If the analysis is performed
m a lean flame the interference can be lessened but the sensitivity will also be reduced
3 The suppression of both Cr (III) and Cr (VI) absorption by most interfering ions in fuel
nch air-acetylene flames is reportedly controlled by the addition of 1% ammonium
bifluonde in 0 2% sodium sulfate [Talanta 20, 631 (1973)] A 1% oxine solution is also
reported to be useful
4 For levels of chromium between 50 and 200 ug/1 where the air-acetylene flame can not
be used or for levels below 50 ug/1, either the furnace procedure or the extraction
procedure is recommended See Method 218 2 for the furnace procedure and Method
218 3 for the chelation-extraction procedure
5 For quality control requirements and optional recommendations for use in drinking
water analyses, see part 10 of the Atomic Absorption Methods section of this manual
6 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 An interlaboratory study on trace metal analyses by atomic absorption was conducted by
the Quality Assurance and Laboratory Evaluation Branch of EMSL Six synthetic
concentrates containing varying levels of aluminum, cadmium, chromium, copper, iron,
manganese, lead and zinc were added to natural water samples The statistical results for
chromium were as follows
Standard
Number True Values Mean Value Deviation Accuracy as
of Labs ug/liter ug/liter ug/hter % Bias
74 370 353 105 -45
76 407 380 128 -65
72 74 72 29 -3 1
70 93 84 35 -102
47 74 10 2 78 37 7
47 150 160 90 68
218 1-2
-------
CHROMIUM
Method 218.2 (Atomic Absorption, furnace technique)
STORET NO. 01034
Dissolved 01030
Suspended 01031
Optimum Concentration Range: 5-100 ug/1
Detection Limit: 1 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Calcium Nitrate Solution Dissolve 11 8 grams of calcium nitrate, Ca(NO3)2 • 4H2O
(analytical reagent grade) in deiomzed distilled water and dilute to 100 ml 1 ml = 20 mg
Ca
3 Prepare dilutions of the stock chromium solution to be used as calibration standards at
the time of analysis The calibration standards should be prepared to contain 0 5% (v/v)
HNO3 To each 100 ml of standard and sample alike, add 1 ml of 30% H2O2 and 1 ml of
the calcium nitrate solution
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 05% v/v HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-1000°C
3 Atomizing Time and Temp 10sec-2700°C
4 Purge Gas Atmosphere Argon
5 Wavelength 357 9 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Approved for NPDES and SDWA
Issued 1978
218 2-1
-------
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul mjecton, continuous flow purge gas and non-pyrolytic
graphite
2 Hydrogen peroxide is added to the acidified solution to convert all chromium to the
tnvalent state Calcium is added to a level above 200 mg/1 where its suppressive effect
becomes constant up to 1000 mg/1
3 Background correction may be required if the sample contains high dissolved solids
4 Nitrogen should not be used as a purge gas because of possible CN band interference
5 Pipet tips have been reported to be a possible source of contamination (See part 5 2 9 of
the Atomic Absorption Methods section of this manual)
6 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
7 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
8. For quality control requirements and optional recommendations for use in drinking
water analyses, see part 10 of the Atomic Absorption Methods section of this manual
9 Data to be entered into STORET must be reported as ug/1
I
Precision and Accuracy
1 In a single laboratory (EMSL), using Cincinnati, Ohio tap water spiked at concentrations
of 19, 48, and 77 ug Cr/1, the standard deviations were ±01, ±0 2, and ±0 8,
respectively Recoveries at these levels were 97%, 101%, and 102%, respectively
218 2-2
-------
CHROMIUM
Method 218.3 (Atomic Absorption, chelation-extraction)
*
STORET NO. 01034
1 Scope and Application
1 1 This method covers the determination of total chromium in drinking, surface and saline
waters The method may also be applicable to certain domestic and industrial wastes
provided that no interfering substances are present (See 3 1)
1 2 The method may be used to analyze samples containing from 1 0 to 25 ug of chromium
per liter
1 3 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
2 Summary of the Method
2 1 This method is based on the chelation of hexavalent chromium with ammonium
pyrrohdme dithiocarbamate (APDC) following oxidation of tnvalent chromium The
chelate is extracted with methyl isobutyl ketone (MIBK) and aspirated into the flame of
the atomic absorption spectrophotometer
2 2 Hexavalent chromium may also be chelated with pyrrohdme dithiocarbamic acid in
chloroform as described in section 9 2 of the atomic absorption text found in this manual
3 Interferences
3 1 High concentrations of other reactive metals, as may be found in wastewaters, may
interfere The method is free from interferences from elements normally occurring in
fresh water
4 Instrumental Parameters (General)
4 1 Chromium hollow cathode lamp
4 2 Wavelength 357 9 nm
4 3 Fuel Acetylene
44 Oxidant Air
4 5 Type of flame Fuel rich (adjust for organic solvent)
5 Reagents
5 1 Ammonium pyrrohdme dithiocarbamate (APDC) solution Dissolve 1 0 g APDC in
demmerahzed water and dilute to 100 ml Prepare fresh daily
5 2 Bromophenol blue indicator solution Dissolve 0 1 g bromophenol blue in 100 ml
50-percent ethanol
5 3 Potassium dichromate standard solution, 10ml = 0 08 mg Cr Dissolve 0 2263 g dried
analytical reagent grade K2Cr2O7 in demmerahzed water and make up to 1000 ml
5 4 Tnvalent chromium stock solution, 10ml = 0 002 mg Cr+3 Pipet 5 00 ml of the
potassium dichromate standard solution (5 3) into an Erlenmeyer flask Add
approximately 15 mg Na2SO3 and 0 5 ml concentrated HNO3 Gently evaporate to
/
Approved for NPDES and SDWA
Issued 1978
218 3-1
-------
dryness, strong heating reoxidizes the chromium Add 05ml concentrated HNO3 and
again evaporate to dryness to destroy any excess sulfite Take up m 1 ml concentrated
HNO3 with warming and dilute to 200 Oml with demmerahzed water
5 5 Trivalent chromium working solution, 10ml =0 005 mg Cr+3 Immediately before
use, dilute 250 ml of tnValent chromium stock solution (54) to 1000 ml with
demmeralized water
5 6 Potassium permanganate, 0 1 N Dissolve 0 32 g potassium permanganate in 100 ml
demmeralized water
5 7 Sodium azide, 01% Dissolve 100 mg sodium azide in deminerahzed water and dilute to
100ml
5 8 Methyl isobutyl ketone (MIBK)
5 9 Sodium hydroxide solution, 1 M Dissolve 40 g NaOH in demmeralized water and dilute
to 1 liter
5.10 Sulfunc acid, 0 12 M Slowly add 6 5 ml concentrated H2SO4 (sp gr 184) to
demmeralized water and dilute to 1 liter
6. Procedure
6 1 Pipet a volume of sample contamig less than 2 5 ug chromium (100 ml maximum) into a
200 ml volumetnc flask, and adjust the volume to approximately 100 ml The pH must
be 2 0 or less Add concentrated HNO3 if necessary
6 2 Acidify a liter of deminerahzed water with 1 5 ml concentrated HNO3 Prepare a blank
and sufficient standards using tnvalent chromium and adjust volumes to approximately
100 ml with the acidified deminerahzed water
6 3 Add 0 1 N KMnO4 dropwise to both standards and samples until a faint pink color
persists
6 4 Heat on a steam bath for 20 minutes If the color disappears, add additional KMnO4
solution dropwise to maintain a slight excess
6 5 While still on the steam bath, add sodium azide solution dropwise until the KMnO4 color
just disappears Heat for about 2 mm between each addition and avoid adding any excess
Continue heating for 5 mm after adding the last drop of sodium azide solution
6 6 Transfer the flasks to a water bath and cool to room temperature
6 7 Remove from the water bath and filter (through Whatman No 40 filter paper or
equivalent) any sample which has a brownish precipitate or coloration which may
interfere with the pH adjustment
6 8 Add 2 0 ml of 1 M NaOH and 2 drops bromophenol blue indicator solution Continue
the addition of 1 M NaOH dropwise to all samples and standards in which the indicator
change from yellow to blue has not occurred Add 0 12 M H2SO4 dropwise until the blue
color just disappears, then add 2 0 ml m excess The pH at this point will be 2 4
6 9 The pH adjustment to 2 4 may also be made with a pH meter instead of using an
indicator
6.10 Add 50ml APDC solution and mix The pH should then be approximately 2 8
611 Add 100ml MIBK and shake vigorously for 3 minutes
6 12 Allow the layers to separate and add demmeralized water until the ketone layer is
completely in the neck of the flask
218 3-2
-------
613 Aspirate the ketone layer, record the instrument reading for each sample and standard
against the blank Repeat, and average the duplicate results
Calculations
7 1 Determine the ug/1 Cr in each sample from a plot of the instrument readings of
standards A working curve must be prepared with each set of samples Report Cr
concentrations as follows Less than 10 ug/1, nearest ug/1, 10 ug/1 and above, two
significant figures
Precision and Accuracy
8 1 Precision and accuracy data are not available at this time
Reference
9 1 Atomic Absorption Newsletter 6, p 128 (1967)
218 3-3
-------
CHROMIUM, HEXAVALENT
Method 218.4 (Atomic Absorption, chelation-extraction)
STORET NO. 01032
1 Scope and Application
1 1 This method covers the determination of dissolved hexavalent chromium in drinking,
surface and saline waters The method may also be applicable to certain domestic and
industrial wastes after filtration provided that no interfernng substances are present (See
41)
1 2 The method may be used to analyze samples containing from 10 to 250 ug of chromium
per liter
2 Summary of the Method
2 1 This method is based on the chelation of hexavalent chromium with ammonium
pyrrohdme dithiocarbamate (APDC) and extraction with methyl isobutyl ketone
(MIBK) The extract is aspirated into the flame of the atomic absorption
spectrophotometer
2 2 Hexavalent chromium may also be chelated with pyrrohdme dithiocarbamic acid in
chloroform as described in section 9 2 of the atomic absorption text found in this manual
A pH of 2 3 must be maintained throughout the extraction
2 3 The diphenylcarbazide colonmetnc procedure as found on p 192 of "Standard Methods
for the Examination of Water and Wastewater", 14th edition, 1975, may also be used
3 Sample Handling and Preservation
3 1 Stability of hexavalent chromium is not completely understood at this time Therefore,
the chelation and extraction should be earned out as soon as possible
32 To retard the chemical activity of hexavalent chromium, the sample should be
transported and stored until time of anlysis at 4°C
4 Interferences
4 1 High concentrations of other reactive metals, as may be found in wastewaters, may
interfere The method is free from interferences from elements normally occurring in
fresh water
5 Instrumental Parameters (General)
5 1 Chromium hollow cathode lamp
5 2 Wavelength 357 9 nm
5 3 Fuel Acetylene
5 4 Oxidant Air
5 5 Type of Flame Fuel rich (adjust for organic solvent)
6 Reagents
6 1 Ammonium pyrrohdme dithiocarbamate (APDC) solution Dissolve 1 0 g APDC in
\ demmeralized water and dilute to 100 ml Prepare fresh daily
Approved for NPDES
Issued 1978
2184-1
-------
62 Bromophenol blue indicator solution Dissolve 0 1 g bromophenol blue in 100 ml
50-percent ethanol
6 3 Chromium standard solution I, 1 0 ml = 100 ug Cr Dissolve 0 2829 g pure, dried
K2Cr2O7 in demmerahzed water and dilute to 1000 ml
6 4 Chromium standard solution II, 1 0 ml = 10 0 ug Cr Dilute 100 ml chromium standard
solution I to 1000 ml with demmerahzed water
6 5 Chromium standard solution III, 1 0 ml = 0 10 ug Cr Dilute 10 0 ml chromium
standard solution II to 1000 ml with deminerahzed water
6 6 Methyl isobutyl ketone (MIBK)
6 7 Sodium hydroxide solution, 1 M Dissolve 40 g NaOH in demmerahzed water and dilute
to 1 liter
6 8 Sulfunc acid, 0 12 M Slowly add 6 5 ml concentrated H2SO4 (sp gr 1 84) to
deminerahzed water and dilute to 1 liter
7 Procedure
7 1 Pipet a volume of sample containing less than 25 ug chromium (100 ml maximum)
into a 200 ml volumetric flask, and adjust the volume to approximately 100 ml
7 2 Prepare a blank and sufficient standards, and adjust the volume of each to approximately
100ml
7 3 Add 2 drops bromophenol blue indicator solution (The pH adjustment to 2 4 may also
be made with a pH meter instead of using an indicator )
7 4 Adjust the pH by addition of 1 M NaOH solution dropwise until a blue color persists
Add 0 12 M H2SO4 dropwise until the blue color just disappears in both the standards
and sample Then add 2 0 ml of 0 12 M H2SO4 in excess The pH at this point should be
24
7 5 Add 5 0 ml APDC solution and mix The pH should then be approximately 2 8
7.6 Add 10 0 ml MIBK and shake vigorously for 3 minutes
7 7 Allow the layers to separate and add demmerahzed water until the ketone layer is
completely in the neck of the flask
7 8 Aspirate the ketone layer and record the scale reading for each sample and standard
against the blank Repeat, and average the duplicate results
8. Calculations
8 1 Determine the ug/1 Cr+s m each sample from a plot of scale readings of standards A
working curve must be prepared with each set of samples Report Cr+6 concentrations as
follows Less than 10 ug/1, nearest ug/1,10 ug/1 and above, two significant figures
9 Precision and Accuracy
91 In a single laboratory (EMSL), using the (PDCA) extraction procedure and Cincinnati
Ohio tap water spiked at a concentration of 50 ug Cr+«/l the standard deviation was
±2.6 with a mean recovery of 96%
2184-2
-------
United States
Environmental Protection
Agency
Environmental Monitoring and
Support Laboratory
Cincinnati OH 45268
Research and Development
vxEPA
Test Method
Chromium, Dissolved
Hexavalent (Atomic
Absorption, Furnace
Technique)—Method 218.5
1 Scope and Application
1 1 This method covers the
determination of dissolved hexavalent
chromium (Cr6+) m drinking and
surface waters The method may also
be applicable to certain domestic and
industrial wastes after filtration
provided that potential interfering
substances are taken into account
(See 41 )
1 2 The method may be used to
analyze samples containing from 5 to
100 yug of Cr6+ per liter The range of
the method may be extended upward
by dilution
2 Summary of Method
2 1 The method is based on the
separation of Cr6+ from the sample by
coprecipitation of lead chromate with
lead sulfate in a solution of acetic
acid After separation, the supernate
is drawn off and the Cr6 precipitate
resolubihzed in nitric acid as tnvalent
chromium (Cr3+) and quantified by
furnace atomic absorption
2 2 Hexavalent chromium may also
be analyzed by the chelation/
extraction technique (see Method
218 4 or the procedure described in
9 2 of the Atomic Absorption methods
found in this manual)
3 Sample Handling and
Preservation
3 1 For sample handling cleaning
glassware and the filtration procedure
see part 4 1 of the Atomic Absorption
Method section of this manual
3 2 The sample must not be
preserved by acidification, but instead
transported and stored until time of
analysis at.4°C
3 3 Stability of Cr6+ in environmental
samples is n ot completely understood
at this time The chemical nature of
the sample matrix can have a definite
affect on the chemistry of chromium
Therefore the analysis should be
carried out as soon as possible but no
longer than 24 hours after collection
4 Interferences
4 1 The possible interference from
other elements which form stable
chromates is not known at this time
4 2 Samples with either sulfate or
chloride concentrations above 1000
mg/liter should be diluted before
analysis
4 3 The potential reduction of Cr6+
from highly reductive substances
increases as pH is lowered When
sulfites and sulfides are present the
2185-1
Dec 1982
-------
sample aliquot taken for analysis
should be neutralized and aerated
before beginning
5. instrument Parameters
(General)
5.1 Drying Time and Temp 30 sec-
125°C
5.2 Ashing Time and Temp 30 sec-
1000°C
5.3 Atomizing Time and Temp 10
sec-2700°C
5.4 Purge Gas Atmosphere Argon
5.5 Wavelength 357 9nm
5 6 Other operating parameters
should be as specified by the
particular instrument manufacturer
6. Special Apparatus
6 1 Glassware
6.1 J Filtering flask, heavy wall, 1
liter capacity
5.1 2 Centrifuge tubes, heavy duty,
conical, graduated, glass stoppered,
10 mL capacity
6.1.3 Pasteur pipets, borosilicate
glass, 5 34 inches
6 2 Centrifuge any centrifuge
capable of reaching 2000 rpm and
accepting the centrifuge tubes
described in 6 1 2 may be used
63 pH Meter a wide variety of
instruments are commercially
available and suitable for this work
6 4 Test Tube Mixer any mixer
capable of thorough vortex is
acceptable
7. Reagents
7.1 Lead Nitrate Solution Dissolve
33 1 grams of lead nitrate, Pb(NO3)2
(analytical reagent grade), in deionized
distilled water and dilute to 100 mL
7.2 Ammonium Sulfate Solution
Dissolve 2 7 grams of ammonium
sulfate, (NH<)2SO< (analytical reagent
grade), in deionized distilled water and
dilute to 100mL
7 3 Calcium Nitrate Solution
Dissolve 118 grams of calcium
nitrate, Ca(NO3)z 4HaO (analytical
reagent grade), in. deionized distilled
water and dilute to 100 mL T mL =
20 mg Ca.
7 4 Nitric Acid, cone Distilled
reagent grade or equivalent to
spectrograde quality
7 5 Acetic Acid, Glacial ACS
reagent grade
751 Acetic Acid, 10% (v/v) Dilute
10 mL glacial acetic acid to 100 mL
with deionized distilled water
7 6 Ammonium Hydroxide, 10%
(v/v) Dilute 10 mL cone ammonium
hydroxide, NH4OH (analytical reagent
grade), to 100 mL with deionized
distilled water
7 7 Hydrogen Peroxide, 30% ACS
reagent grade
7 8 Potassium Dichromate Standard
Solution Dissolve 2 8285 grams of
dried potassium dichromate, KaCraO?
(analytical reagent grade), in deionized
distilled water and dilute to 1 liter 1
mL = 1 mg Cr (1000 mg/L)
7 9 Tnvalent Chromium Working
Stock Solution To 50 mL of the
potassium dichromate standard
solution (7 8) add 1 mL of 30% H202
(7 7) and 1 mL cone HN03 (7 4) and
dilute to 100 mL with deionized
distilled water 1 mL = 0 5 mg Cr3+
Prepare fresh monthly or as needed
8 Calibration
81 At the time of analysis prepare a
blank and a series of at least four
calibration standards from the Cr3+
working stock (7 9) that will
adequately bracket the sample The
normal working range covers a
concentration range of 5 to 100 ug
Cr/L Add to the blank and each
standard 1 mL 30% H2O2 (7 7), 5 mL
CONC HNOa (7 4), and 1 mL calcium
nitrate solution (7 3) for each 100 mL
of prepared solution before diluting to
final volume These calibration
standard should be prepared fresh
weekly or as needed
8 2 The listed instrumental
conditions (5 ) and the stated
calibration concentration range are for
a Perkm-Elmer HGA-2100 based on
the use of a 20/uL injection, contmous
flow purge gas and non-pyrolytic
graphite The use of simultaneous
background correction is required for
both calibration and sample analysis
9 Procedure
9 1 Transfer a 50 mL portion of the
filtered sample to a 10OmL Griffin
beaker and adjust to pH 3 5±0 3 by
adding 10% acetic acid dropwise
Record the volume of acid added and
adjust the final result to account for
the dilution
Note Care must be exercised not to
take the pH below 3 If the pH is
inadvertently lowered to < 3, 10%
NH4OH (7 6) should be used to raise
the pH to above 3
9 2 Pipet a 10 mL aliquot of the
adjusted sample into a centrifuge tube
(6 1 2) Add 100/A. of the lead nitrate
solution (7 1), stopper the tube, mix the
sample and allow to stand for 3mm
9 3 After the formation of lead
chromate, retain the Cr3+ complex in
solution by addition of 0 5 mL glacial
acetic acid (7 5) Stopper and mix
94 To provide adequate lead sulfate
for coprecipitation add 100 mL
ammonium sulfate solution (7 2),
stopper and mix
9 5 Place the stoppered centrifuge
tube in the centrifuge, making sure
that the tube is properly
counterbalanced Start the centrifuge
and slowly increase the speed to
2000 rpm in small increments over a
period of 5 mm Centrifuge the sam-
ple at 2000 rpm for 10 mm
Note 2 The speed of the centrifuge
must be increased slowly to insure
complete coprecipitation
9 6 After centrifugmg remove the
tube and draw off the supernate using
the apparatus detailed in Figure 1 As
the pasteur pipet is lowered into the
tube the supernate is sucked into the
filtering flask With care the supernate
can be withdrawn to within
approximately 0 1 mL above the
precipitate
97 To the remaining precipitate add
0 5 mL cone HN03 (7 4), 100/L/L 30%
H202 (7 7) and 100//L calcium nitrate
solution (7 3) Stopper the tube and
mix using a vortex mixer to disrupt
the precipitate and solubilize the lead
chromate Dilute to 10mL, mix and
analyze in the same manner as the
calibration standard (8 2)
9 8 For the general furnace
procedure and calculation, see
Furnace Procedure part 9 3 of the
Atomic Absorption Methods section of
this manual
10 Verification
101 For every sample matrix
analyzed verification is necessary to
determine that neither a reducing
condition nor a chemical interference
affecting precipitation is present This
Dec 1982
2185-2
-------
must be accomplished by analyzing a
second 10mL aliquot of the pH
adjusted filtrate (9 1) spiked with Cr6*
(7 8) The amount of spike added
should double the concentration found
in the original aliquot Under no
circumstance should the increase be
of less than 3Qug Cr6+/L To verify the
absence of an interference the spike
recovery should be between 85% and
115%
102 If the addition of the spike
extends the concentration beyond the
range of the calibration curve, the
analysis solution should be diluted
with blank solution and the calculated
results adjusted accordingly
103 If the verification indicates a
suppressive interference, the sample
should be diluted and reanalyzed
11 Analytical Notes
111 Nitrogen should not be used as
a purge gas because of possible CN
band interference
112 The use of pyrolytic graphite
should be avoided when possible
Generally, pyrolytic graphite resulted
in a more limited analytical working
range and in some situations an
enhancement effect
113 Pipet tips have been reported
to be a possible source of
contamination (See part 5 2 9 of the
Atomic Absorption Methods section of
this manual)
114 The method of standard
addition should not be required in as
much as the Cr6+ has been separated
from the original sample solution and
redissolved in a uniform matrix having
an absorption response coincident to
the calibration curve
115 Data to be entered into
STORET (No 01032) must be reported
as jug/L
123 Using Cincinnati, Ohio tap
water spiked at concentrations of
5,10, and 50 //g Cr6+/L the standard
deviations were ±07, ±0 6, and
±0 6 respectively Spike recovery at
all three levels was 102%
124 A 1000 fjtS Cr3VL standard
solution analyzed by this method
yielded a result of 8 yug Cr6+/L with a
relative standard deviation of 19%
125 The data from 5 /jg Cr6+/L tap
water spike was used to calculate
method detection limit (MDL) with
99% confidence as described in
Trace Analyses for Wastewater," J
Glaser, D Foerst, G McKee, S
Quave, W Budde, Environmental
Science and Technology Vol 15,
Number 12, page 1426, December
1981 The calculated MDL for
Cincinnati drinking water is 2 3 /ug/L
12 Precision and Accuracy
121 In a single laboratory (EMSL)
using a mixed industrial-domestic
waste effluent containing 22 /ug
Cr8VL and spiked with a
concentration of 50 A/g Cr8Vl_ the
standard deviations were ±10 and ±
2 7, respectively with a spike recovery
of 94%
122 Recoveries of a 40 /ug Cr6VL
spike in diluted tannery and plating
waste effluents were 96% and 93%,
respectively
2185 3
Dec 1982
-------
COBALT
Method 219.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01037
Dissolved 01035
Suspended 01036
Optimum Concentration Range: 0 5-5 mg/1 using a wavelength of 240 7 nm
Sensitivity. 0 2 mg/1
Detection Limit: 0 05 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 4 307 g of cobaltous chloride, CoCl2»6H2O (analytical reagent
grade), in deiomzed distilled water Add 10 ml of concentrated nitric acid and dilute to 1
liter with deiomzed distilled water 1 ml = 1 mg Co (1000 mg/1)
2 Prepare dilutions of the stock cobalt solution to be used as calibration standards at the
time of analysis The calibration standards should be prepared using the same type of
acid and at the same concentration as will result in the sample to be analyzed either
directly or after processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 thru 4 1 4 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
Instrumental Parameters (General)
1 Cobalt hollow cathode lamp
2 Wavelength 240 7 nm
3 Fuel Acetylene
4 Oxidant Air
5 Type of Flame Oxidizing
Analysis Procedure
1 For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Approved for NPDES
Issued 1974
Editorial revision 1978
219 1-1
-------
Notes
1 For levels of cobalt below 100 ug/1, either the Special Extraction Procedure, given in
part 9 2 of the Atomic Absorption Methods section or the furnace technique, Method
219 2 is recommended
2 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 In a single laboratory (EMSL), using a mixed industrial-domestic waste effluent at
concentrations of 0 20,1 0 and 5 Omg Co/1, the standard deviations were ±0 013, ±0 01
and ±005, respectively Recoveries at these levels were 98%, 98%, and 97%,
respectively
219 1-2
-------
COBALT
Method 219.2 (Atomic Absorption, furnace technique)
STORET NO. Total 01037
Dissolved 01035
Suspended 01036
Optimum Concentration Range: 5-100 ug/1
Detection Limit: 1 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 0 5 % (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 05% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125'C
2 Ashing Time and Temp 30sec-900°C
3 Atomizing Time and Temp 10sec-2700°C
4 Purge Gas Atmosphere Argon
5 Wavelength 240 7 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and non-pyrolytic
Approved for NPDES
Issued 1978
2192-1
-------
graphite Smaller size furnace devices or those employing faster rates of atomization can
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings
2 The use of background correction is recommended
3. Nitrogen may also be used as the purge gas but with reported lower sensitivity
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier m part 8 5
of the Atomic Absorption Methods section of this manual
6 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 Precision and accuracy data are not available at this time
219 2-2
-------
CQPPER
Method 220.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01042
Dissolved 01040
Suspended 01041
Optimum Concentration Range: 0 2-5 mg/1 using a wavelength of 324 7 nm
Sensitivity: 0 1 mg/1"
Detection Limit: 002 mg/1
Preparation of Standard Solution
1 Stock Solution Carefully weigh 1 00 g of electrolyte copper (analytical reagent grade)
Dissolve in 5 ml redistilled HNO3 and make up to 1 liter with deiomzed distilled water
Final concentration is 1 mg Cu per ml (1000 mg/1)
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared using the same type of acid and at
the same concentration as will result m the sample to be analyzed either directly or after
processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 thru 4 1 4 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
Instrumental Parameters (General)
1 Copper hollow cathode lamp
2 Wavelength 324 7 nm
3 Fuel Acetylene
4 Oxidant Air
5 Type of flame Oxidizing
Analysis Procedure
1 For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Approved for NPDES
Issued 1971
Editorial revision 1974 and 1978
220 1-1
-------
Notes
1 For levels of copper below 50 ug/1, either the Special Extraction Procedure, given in part
9 2 of the Atomic Absorption Methods section or the furnace technique, Method 220 2,
is recommended
2. Numerous absorption lines are available for the determination of copper By selecting a
suitable absorption wavelength, copper samples may be analyzed over a very wide range
of concentration The folio wing lines may be used
327.4 nm Relative Sensitivity 2
216.5 nm Relative Sensitivity 7
222.5 nm Relative Sensitivity 20
3 Data to be entered into STORET must be reported as ug/1
4 The 2,9-dimethyl-l, 10-phenanthrohne colonmetnc method may also be used (Standard
Methods, 14th Edition, p 196)
Precision and Accuracy
1. An mterlaboratory study on trace metal analyses by atomic absorption was conducted by
the Quality Assurance and Laboratory Evaluation Branch of EMSL Six synthetic
concentrates containing varying levels of aluminum, cadmium, chromium, copper, iron,
manganese, lead and zinc were added to natural water samples The statistical results for
copper were as follows
Standard
Number True Values Mean Value Deviation Accuracy as
of Labs ug/liter ug/liter ug/hter % Bias
91 302 305 56 09
92 332 324 56 -24
86 60 64 23 70
84 75 76 22 13
66 75 97 61 297
66 120 139 97 155
220 1-2
-------
COPPER
Method 220.2 (Atomic Absorption, furnace technique)
STORET NO. 01042
Dissolved 01040
Suspended 01041
Optimum Concentration Range: 5-100 ug/1
Detection Limit: lug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 05% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 05% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-'900°C
3 Atomizing Time and Temp 10sec-2700°C
4 Purge Gas Atmosphere Argon
5 Wavelength 324 7 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and non-pyrolytic
Approved for NPDES
Issued 1978
220 2-1
-------
graphite Smaller size furnace devices or those employing faster rates of atomization can
be operated using lower atomization temperatures for shorter time penods than the
above recommended settings
2 Background correction may be required if the sample contains high dissolved solids
3 Nitrogen may also be used as the purge gas
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5. If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
6 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 Precision and accuracy data are not available at this time
220 2-2
-------
GOLD
Method 231.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 71910
Optimum Concentration Range: 0 5-20 mg/1 using a wavelength of 242 8 nm
Sensitivity: 0 25 mg/1
Detection Limit: 0 1 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 0 1000 g of gold metal in a minimum volume of aqua regiaf
Take to near dryness, cool, add 5 ml HC1, and dilute to 100 ml with deionized water
Store in an amber glass bottle (1 ml = 1 mg Au)
2 A standard AAS solution of chloroaunc acid, HAuCl4, 1000 mg/1 in aqueous matrix is
available from Alfa Products, Beverly, Massachusetts 01915
Cat #88068
3 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared to contain 05% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Transfer a representative aliquot of the well mixed sample to a Griffin beaker and add 3
ml of cone distilled HNO3 Place the beaker on a steam bath and evaporate to near
dryness Cool the beaker and cautiously add a 5 ml portion of aqua regia (See below for
preparation of aqua regia f) Cover the beaker with a watch glass and return to the steam
bath Continue heating the covered beaker for 30 minutes Remove cover and evaporate
to near dryness Cool and add 1 1 distilled HNO3 (1 ml per 100 ml dilution) Wash down
the beaker walls and watch glass with distilled water and filter the sample to remove
silicates and other insoluble material that could clog the atomizer Adjust the volume to
some predetermined value based on the expected metal concentration The sample is now
ready for analysis
fAqua regia-prepare immediately before use by carefully adding three volumes of
cone HCL to one volume of cone HNO3
Approved for NPDES
Issued 1976
Technical revision 1978
231 1-1
-------
Instrumental Parameters (General)
1 Gold hollow cathode lamp
2 Wavelength 242 8 nm
3 Fuel Acetylene
4 Oxidant Air
5. Type of flame Oxidizing
Analysis Procedure
1. For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
%
Notes
1 For concentrations of gold below 100 ug/1, the furnace procedure, Method 231 2, is
recommended
Precision and Accuracy
1. Precision and accuracy data are not available at this time
231 1-2
-------
GOLD
Method 231.2 (Atomic Absorption, furnace technique)
STORET NO. 71910
Optimum Concentration Range: 5-100 ug/1
Detection Limit: 1 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 0 5% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 0 5% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-600°C
3 Atomizing Time and Temp 10sec-2700°C
4 Purge Gas Atmosphere Argon
5 Wavelength 242 8 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of his manual
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and non-pyrolytic
graphite
Approved for NPDES
Issued 1978
231 2-1
-------
2 The use of background correction is recommended
3 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
4 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
5 Data to entered into STORET must be reported as ug/1
ii i<
Precision and Accuracy
1 Precision and accuracy data are not available at this time
231 2-2
-------
IRIDIUM
" i •
Method 235.1 (Atomic Absorption, direct aspiration)
STORET NO. Total*
Optimum Concentration Range: 20-500 mg/1 using a wavelength of 264 0 nm
Sensitivity: 8 mg/1
Detection Limit* 3 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 1 147 g of ammonium chloroindate (NH4)2 IrCl6, in a minimum
volume of 1 % (v/v) HC1 and dilute to 100 ml with 1 % HC1 (1 ml = 5 mg Ir)
2 A standard AAS solution of chloroindic acid, H2IrCl6, 1000 mg/1 in aqueous matrix is
available from Alfa Products, Beverly, Massachusetts 01915
* Cat #88072
3 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared to contain 05% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Transfer a representative aliquot of the well mixed sample to a Gnffiu beaker and add 3
ml of cone distilled HNO3 Place the beaker on a steam bath and evaporate to near
dryness Cool the beaker and cautiously add a 5 ml portion of aqua regia (See below for
preparation of aqua regia f) Cover the beaker with a watch glass and return to the steam
bath Continue heating the covered beaker for 30 minutes Remove cover and evaporate
to near dryness Cool and add 1 1 distilled HNO3 (1 ml per 100 ml dilution) Wash down
the beaker walls and watch glass with distilled water and filter the sample to remove
silicates and other insoluble material that could clog the atomizer Adjust the volume to
some predetermined value based on the expected metal concentration The sample is now
ready for analysis
fAqua regia-prepare immediately before use by carefully adding three volumes
cone HC1 to one volume of cone HNO3
*Not Assigned
Approved for NPDES
Issued 1976
Technical revision 1978
235 1-1
-------
Instrumental Parameters (General)
1. Indium hollow cathode lamp
2. Wavelength 264 Onm
3 Fuel Acetylene
4 Oxidant Air
' MI
5. Type of flame Reducing
Analysis Procedure
1. For analysis and calculation, see "Direct Aspiration", part 9 1 of the Atomic Absorption
Methods section of this manual
Notes
1. For concentrations of indium below 3 mg/1, the furnace procedure, Method 235 2, is
recommended
Precision and Accuracy
1. Precision and accuracy data are not available at this time
235 1-2
-------
IRIDIUM
Method 235.2 (Atomic Absorption, furnace technique)
STORET NO. Total*
Optimum Concentration Range: 0 1-1 5mg/l
Detection Limit: 0 03 mg/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calculation standard should be diluted to contain 05% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as descnbed under "direct aspiration method" Sample solutions for analysis
should contain 0 5% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-600°C
3 Atomizing Time and Temp 10sec-2800°C
4 Purge Gas Atmosphere Argon
5 Wavelength 264 Onm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
*Not Assigned
Approved for NPDES
Issued 1978
235 2-1
-------
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and pyrolytic
graphite
2 The use of background correction is recommended
3 Nitrogen may also be used as the purge gas
4 The 208 9 nm line is a factor of 3X more sensitive than the 264 0 nm line, but requires a
very narrow slit to be discriminated from nearby non-absorbing lines
5 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
6 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
Precision and Accuracy
1 Precision and accuracy data are not available at this time
235 2-2
-------
IRON
Method 236.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01045
Dissolved 01046
Suspended 01044
Optimum Concentration Range: 0 3-5 mg/1 using a wavelength of 248 3 nm
Sensitivity: 0 12 mg/1
Detection Limit 0 03 mg/1
Preparation of Standard Solution
1 Stock Solution Carefully weigh 1 000 g of pure iron wire (analytical reagent grade) and
dissolve in 5 ml redistilled HNO3, warming if necessary When solution is complete make
up to 1 liter with deiomzed distilled water 1 ml = 1 mg Fe (1000 mg/1)
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared using the same type of acid and at
the same concentration as will result in the sample to be analyzed either directly or after
processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 thru 4 1 4 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
Instrumental Parameters (General)
1 Iron hollow cathode lamp
2 Wavelength 248 3 nm
3 Fuel Acetylene
4 Oxidant Air
5 Type of flame Oxidizing
Analysis Procedure
1 For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Approved for NPDES
Issued 1971
Editorial revision 1974 and 1978
236 1-1
-------
Notes
1 The following lines may also be used
248 8 nm Relative Sensitivity 2
271 9 nm Relative Sensitivity 4
302 1 nm Relative Sensitivity 5
252 7 nm Relative Sensitivity 6
372 0 nm Relative Sensitivity 10
2 Data to be reported into STORET must be reported as ug/1
3. The 1,10-phenanthrokne colonmetnc method may also be used (Standard Methods,
14th Edition, p 208)
4. For concentrations of iron below 0 05 mg/1, either the Special Extraction Procedure
given m part 9 2 of the Atomic Absorption Methods section or the furnace procedure,
Method 236 2, is recommended
Precision and Accuracy
1 An mterlaboratory study on trace metal analyses by atomic absorption was conducted by
the Quality Assurance and Laboratory Evaluation Branch of EMSL Six synthetic
concentrates containing varying levels of aluminum, cadmium, chrommm, copper, iron,,
manganese, lead and zinc were added to natural water samples The statistical results for
iron were as follows
Standard
Number True Values Mean Value Deviation Accuracy as
Of Labs ug/liter ug/liter ug/hter % Bias
82 840 855 173 1 8
85 700 680 178 -28
78 350 348 131 -Or5
79 438 435 183 -07
57 24 58 69 141
54 10 48 69 382
236 1-2
-------
IRON
Method 236.2 (Atomic Absorption, furnace technique)
STORET NO. Total 01045
Dissolved 01046
Suspended 01044
Optimum Concentration Range: 5-100 ug/1
Detection Limit: 1 ug/1
Preparation of Standard Solution
1 Stock Solution Prepare as described under "direct aspiration method"
2, Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 0 5 % (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as descnbed under "direct aspiration method" Sample solutions for analysis
should contain 0 5% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-1000°C
3 Atomizing Time and Temp 10sec-2700°C
4 Purge Gas Atmosphere Argon
5 Wavelength 248 3 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and non-pyrolytic
Approved for NPDES
Issued 1978
236 2-1
-------
graphite Smaller size furnace devices or those employing faster rates of atomization can
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings
2 The use of background correction is recommended
3 Nitrogen may also be used as the purge gas
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
6 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 Precision and accuracy data are not available at this time
236 2-2
-------
LEAD
Method 239.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01051
Dissolved 01049
Suspended 01050
Optimum Concentration Range: 1-20 mg/1 using a wavelength of 283 3 nm
Sensitivity: 0 5 mg/1
Detection Limit: 0 1 mg/1
Preparation of Standard Solution
1 Stock Solution Carefully weigh 1 599 g of lead nitrate, Pb(NO3)2 (analytical reagent
grade), and dissolve in deiomzed distilled water When solution is complete acidify with
10 ml redistilled HNO3 and dilute to 1 liter with deiomzed distilled water 1 ml = 1 mg
Pb (1000 mg/1)
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared using the same type of acid and at
the same concentration as will result in the sample to be analyzed either directly or after
processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 thru 4 1 4 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
Instrumental Parameters (General)
1 Lead hollow cathode lamp
2 Wavelength 283 3 nm
3 Fuel Acetylene
4 Oxidant Air
5 Type of flame Oxidizing
Analysis Procedure
1 For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Approved for NPDES and SDWA
Issued 1971
Editorial revision 1974 and 1978
239 1-1
-------
Notes
1. The analysis of this metal is exceptionally sensitive to turbulence and absorption bands in
the flame Therefore, some care should be taken to position the light beam m the most
stable, center portion of the flame To do this, first adjust the burner to maximize the
absorbance reading with a lead standard Then, aspirate a water blank and make minute
adjustments in the burner alignment to minimize the signal
2 For levels of lead below 200 ug/1, either the Special Extraction Procedure given in part
9 2 of the Atomic Absorption Methods section or the furnace technique, Method 239 2,
is recommended
3. The following lines may also be used
217 0 nm Relative Sensitivity 0 4
261 4 nm Relative Sensitivity 10
4 For quality control requirements and optional recommendations for use in drinking
water analyses, see part 10 of the Atomic Absorption Methods section of this manual
5 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 An Intel-laboratory study on trace metal analyses by atomic absorption was conducted by
the Quality Assurance and Laboratory Evaluation Branch of EMSL Six synthetic
concentrates containing varying levels of aluminum, cadmium, chromium, copper, iron,
manganese, lead and zinc were added to natural water samples The statistical results for
lead were as follows
Standard
Number True Values Mean Value Deviation Accuracy as
of Labs ug/hter ug/liter ug/liter % Bias
74 367 377 128 29
74 334 340 111 18
64 101 101 46 -O2
64 84 85 40 11
61 37 41 25 96
60 25 31 22 257
239 1-2
-------
LEAD
Method 239.2 (Atomic Absorption, furnace technique)
STORET NO. Total 01051
Dissolved 01049
Suspended 01050
Optimum Concentration Range: 5-100 ug/1
Detection Limit: 1 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as descnbed under "direct aspiration method"
2 Lanthanum Nitrate Solution Dissolve 58 64 g of ACS reagent grade La2O3 in 100 ml
cone HNO3 and dilute to 1000 ml with deiomzed distilled water 1 ml = 50 mg La
3 Working Lead Solution Prepare dilutions of the stock lead solution to be used as
calibration standards at the time of analysis Each calibration standard should contain
05% (v/v) HNO3 To each 100 ml of diluted standard add 10 ml of the lanthanum
nitrate solution
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section qf this manual
Sample Preparation
1 Prepare as descnbed under "direct aspiration method" Sample solutions for analysis
should contain 05% (v/v) HNO3
2 To each 100 ml of prepared sample solution add 10 ml of the lanthanum nitrate solution
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-500°C
3 Atomizing Time and Temp 10sec-2700°C
4 Purge Gas Atmosphere Argon
5 Wavelength 283 3 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure in the calculation see "Furnace Procedure", part 9 3 of the
Atomic Absorption Methods section of this manual
Approved for NPDES and SDWA
Issued 1978
239 2-1
-------
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 u\ injection, continuous flow purge gas and non-pyrolytic
graphite Smaller size furnace devices or those employing faster rates of atomization can
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings '
2 The use of background correction is recommended
3 Greater sensitivity can be achieved using the 2170 nm line, but the optimum
concentration range is reduced The use of a lead electrodeless discharge lamp at this
lower wavelength has been found to be advantageous Also a lower atomization
temperature (2400°C) may be preferred
4 To suppress sulfate interference (up to 1500 ppm) lanthanum is added as the nitrate to
both samples and calibration standards (Atomic Absorption Newsletter Vol 15, No 3,
p 71, May-June 1976)
5 Since glassware contamination is a severe problem in lead analysis, all glassware should
be cleaned immediately prior to use, and once cleaned, should not be open to the
atmosphere except when necessary
6 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
7 For quality control requirements and optional recommendations for use in drinking
water analyses, see part 10 of the Atomic Absorption Methods section of this manual
8 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
9 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 In a single laboratory (EMSL), using Cincinnati, Ohio tap water spiked at concentrations
of 25, 50, and 100 ug Pb/1, the standard deviations were ±\ 3, ±1 6, and ±37,
respectively Recoveries at these levels were 88%, 92%, and 95% respectively
239 2-2
-------
MAGNESIUM
Method 242.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 00927
Dissolved 00925
Suspended 00926
Optimum Concentration Range: 0 02-0 5 mg/1 using a wavelength of 285 2 nm
Sensitivity: 0 007 mg/1
Detection Limit: 0 001 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 0 829 g of magnesium oxide, MgO (analytical reagent grade), in
10 ml of redistilled HNO3 and dilute to 1 liter with deiomzed distilled water 1 ml = 0 50
mgMg (500 mg/1)
2 Lanthanum chloride solution Dissolve 29 g of La2O3, slowly and in small portions in 250
ml cone HC1, (Caution Reaction is violent), and dilute to 500 ml with deiomzed distilled
water
3 Prepare dilutions of the stock magnesium solution to be used as calibration standards at
the time of analysis To each 10 ml volume of calibration standard and sample alike add
1 0 ml of the lanthanum chloride solution, i e , 20 ml of standard or sample +2 ml LaCl3
= 22 ml
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 For the analysis of total magnesium in domestic and industrial effluents, the procedures
for the determination of total metals as given in parts 413 and 4 1 4 of the Atomic
Absorption Methods section of this manual have been found to be satisfactory
2 For ambient waters, a representative aliquot of a well-mixed sample may be used directly
for analysis If suspended solids are present m sufficient amounts to clog the nebulizer,
the sample may be allowed to settle and the supernatant liquid analyzed directly
3 Samples should be preserved with (11) nitric acid to a pH of 2 at the time of collection
Instrumental Parameters (General)
1 Magnesium hollow cathode lamp
2 Wavelength 285 2 nm
Approved for NPDES
Issued 1971
Editorial revision 1974 and 1978
242 1-1
-------
3. Fuel Acetylene
4. Oxidant Air
5 Type of flame Oxidizing
Notes
1. The interference caused by aluminum at concentrations greater than 2 mg/1 is masked
by addition of lanthanum Sodium, potassium and calcium cause no interference at
concentrations less than 400 mg/1
2. The following line may also be used
202 5 nm Relative Sensitivity 25
3 To cover the range of magnesium values normally observed in surface waters (0 1-20
mg/1), it is suggested that either the 202 5 nm line be used or the burner head be rotated
A 90' rotation of the burner head will produce approximately one-eighth the normal
sensitivity
4 Data to be entered into STORET must be reported as mg/1
5 The gravimetric method may also be used (Standard Methods, 14th Edition, p 221)
Precision and Accuracy
1 In a single laboratory (EMSL), using distilled water spiked at concentrations of 2 1 and
8 2 mg Mg/1 the standard deviations were ±0 1 and ±0 2, respectively Recoveries at
both of these levels were 100%
242 1-2
-------
MANGANESE
Method 243.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01055
Dissolved 01056
Suspended 01054
%
Optimum Concentration Range: 0 1-3 mg/1 using a wavelength of 279 5 nm
Sensitivity: 0 05 mg/1
Detection Limit: 001 mg/1
Preparation of Standard Solution
1 Stock Solution Carefully weigh 1 000 g of manganese metal (analytical reagent grade)
and dissolve in 10 ml of redistilled HNO3 When solution is complete, dilute to 1 liter
withl%(V/V)HCl 1ml = ImgMn (1000 mg/1)
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared using the same type of acid and at
the same concentration as will result in the sample to be analyzed either directly or after
processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 thru 4 1 4 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
Instrumental Parameters (General)
1 Manganese hollow cathode lamp
2 Wavelength 279 5 nm
3 Fuel Acetylene
4 Oxidant Air
5 Type of flame Oxidizing
Analysis Procedure
1 For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Approved for NPDES
Issued 1971
Editorial revision 1974 and 1978
243 1-1
-------
Notes
1 For levels of manganese below 25 ug/1, either the furnace procedure, Method 243 2, or
the Special Extraction Procedure given in part 9 2 of the Atomic Absorption Methods
section is recommended The extraction is earned out at a pH of 4 5 to 5 The manganese
chelate is very unstable and the analysis must be made without delay to prevent its re-
solution in the aqueous phase
2 The following line may also be used
403.1 nm Relative Sensitivity 10
3 Data to be entered into STORET must be reported as ug/1
4 The persulfate colonmetnc method may also be used (Standard Methods, 14th Edition,
p225)
Precision and Accuracy
1 An mterlaboratory study on trace metal analyses by atomic absorption was conducted by
the Quality Assurance and Laboratory Evaluation Branch of EMSL Six synthetic
concentrates containing varying levels of aluminum, cadmium, chromium, copper, iron,
manganese, lead and zinc were added to natural water samples The statistical results for
manganese were as follows
Standard
Number True Values Mean Value Deviation Accuracy as
of Labs ug/liter ug/liter ug/hter % Bias
77 426 432 70 1 5
78 469 474 97 12
71 84 86 26 21
70 106 104 31 -21
55 11 21 27 93
55 17 21 20 22
243 1-2
-------
MANGANESE
Method 243.2 (Atomic Absorption, furnace technique)
STORET NO. Total 01055
Dissolved 01056
Suspended 01054
Optimum Concentration Range 1-30 ug/1
Detection Limit: 0 2 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 05% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 05% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-1000°C
3 Atomizing Time and Temp 10sec-2700°C
4 Purge Gas Atmosphere Argon
5 Wavelength 279 5 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Notes
1 The above concentration values and instrument conditions are for a Perkin-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and non-pyrolytic
Approved for NPDES
Issued 1978
243 2-1
-------
graphite Smaller size furnace devices or those employing faster rates of atomization can
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings
2 The use of background correction is recommended
3 Nitrogen may also be used as the purge gas
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
6. Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 Precision and accuracy data are not available at this time
243 2-2
-------
MERCURY
Method 245.1 (Manual Cold Vapor Technique)
STORET NO. Total 71900
Dissolved 71890
Suspended 71895
Scope and Application
1 1 This method is applicable to drinking, surface, and saline waters, domestic and industrial
wastes
12 In addition to inorganic forms of mercury, organic mercurials may also be present These
organo-mercury compounds will not respond to the cold vapor atomic absorption
technique unless they are first broken down and converted to mercuric ions Potassium
permanganate oxidizes many of these compounds, but recent studies have shown that a
number of organic mercurials, including phenyl mercuric acetate and methyl mercuric
chloride, are only partially oxidized by this reagent Potasssmm persulfate has been
found to give approximately 100% recovery when used as the oxidant with these
compounds Therefore, a persulfate oxidation step following the addition of the
permanganate has been included to insure that organo-mercury compounds, if present,
will be oxidized to the mercuric ion before measurement A heat step is required for
methyl mercuric chloride when present m or spiked to a natural system For distilled
water the heat step is not necessary
1 3 The range of the method may be varied through instrument and/or recorder expansion
Using a 100 ml sample, a detection limit of 0 2 ug Hg/1 can be achieved, concentrations
below this level should be reported as < 0 2 (see Appendix 112)
Summary of Method
2 1 The flameless A A procedure is a physical method based on the absorption of radiation at
253 7 nm by mercury vapor The mercury is reduced to the elemental state and aerated
from solution in a closed system The mercmy vapor passes through a cell positioned in
the light path of an atomic absorption spectrophotometer Absorbance (peak height) is
measured as a function of mercury concentration and recorded in the usual manner
Sample Handling and Preservation
3 1 Until more conclusive data are obtained, samples should be preserved by acidification
with nitric acid to a pH of 2 or lower immediately at the time of collection If only
dissolved mercury is to be determined, the sample should be filtered through an all glass
apparatus before the acid is added For total mercury the filtration is omitted
Interference
4 1 Possible interference from sulfide is eliminated by the addition of potassium
permanganate Concentrations as high as 20 mg/1 of sulfide as sodium sulfide do not
interfere with the recovery of added inorganic mercury from distilled water
Approved for NPDES and SDWA
Issued 1974
245 1-1
-------
4 2 Copper has also been reported to interfere, however, copper concentrations as high as 10
mg/1 had no effect on recovery of mercury from spiked samples
43 Sea waters, brines and industrial effluents high in chlorides require additional
permanganate (as much as 25 ml) During the oxidation step, chlorides are converted to
free chlorine which will also absorb radiation of 253 nm Care must be taken to assure
that free chlorine is absent before the mercury is reduced and swept into the cell This
may be accomplished by using an excess of hydroxylamme sulfate reagent (25 ml) In
addition, the dead air space in the BOD bottle must be purged before the addition of
stannous sulfate Both inorganic and organic mercury spikes have been quantitatively
recovered from sea water using this technique
4 4 Interference from certain volatile organic materials which will absorb at this wavelength
is also possible A preliminary run without reagents should determine if this type of
interference is present (see Appendix 111)
5. Apparatus
5 1 Atomic Absorption Spectrophotometer (See Note 1) Any atomic absorption unit having
an open sample presentation area in which to mount the absorption cell is suitable
Instrument settings recommended by the particular manufacturer should be followed
Note 1 Instruments designed specifically for the measurement of mercury using the cold
vapor technique are commercially available and may be substituted for the atomic
absorption Spectrophotometer
5.2 Mercury Hollow Cathode Lamp Westinghouse WL-22847, argon filled, or equivalent
5 3 Recorder Any multi-range variable speed recorder that is compatible with the UV
detection system is suitable
54 Absorption Cell Standard Spectrophotometer cells 10 cm long, having quartz end
windows may be used Suitable cells may be constructed from plexiglass tubing, 1" O D
X 4-1/2" The ends are ground perpendicular to the longitudinal axis and quartz
windows (1" diameter X 1/16" thickness) are cemented in place The cell is strapped to a
burner for support and aligned in the light beam by use of two 2" by 2" cards One inch
diameter holes are cut in the middle of each card, the cards are then placed over each end
of the cell The cell is then positioned and adjusted vertically and horizontally to give the
maximum transmittance
5.5 Air Pump Any peristaltic pump capable of delivering 1 liter of air per minute may be
used A Masterflex pump with electronic speed control has been found to be satisfactory
5 6 Flowmeter Capable of measuring an air flow of 1 liter per minute
5 7 Aeration Tubing A straight glass frit having a coarse porosity Tygon tubing is used for
passage of the mercury vapor from the sample bottle to the absorption cell and return
5 8 Drying Tube 6" X 3/4" diameter tube containing 20 g of magnesium perchlorate (see
Note 2) The apparatus is assembled as shown in Figure 1
NOTE 2: In place of the magnesium perchlorate drying tube, a small reading lamp with
60W bulb may be used to prevent condensation of moisture inside the cell The lamp is
positioned to shine on the absorption cell maintaining the air temperature in the cell
about 10°C above ambient
245 1-2
-------
Reagents
6 1 Sulfunc Acid, Cone Reagent grade
611 Sulfunc acid, 0 5 N Dilute 14 0 ml of cone sulfunc acid to 1 0 liter
6 2 Nitric Acid, Cone Reagent grade of low mercury content (See Note 3)
NOTE 3: If a high reagent blank is obtained, it may be necessary to distill the nitric acid
6 3 Stannous Sulfate Add 25 g stannous sulfate to 250 ml of 0 5 N sulfunc acid This
mixture is a suspension and should be stirred continuously during use (Stannous
chloride may be used in place of stannous sulfate )
6 4 Sodium Chlonde-Hydroxylamme Sulfate Solution Dissolve 12 g of sodium chloride and
12 g of hydroxylamme sulfate in distilled water and dilute to 100 ml (Hydroxylamme
hydrochlonde may be used in place of hydroxylamme sulfate )
6 5 Potassium Permanganate 5% solution, w/v Dissolve 5 g of potassium permanganate in
100 ml of distilled water
6 6 Potassium Persulfate 5% solution, w/v Dissolve 5 g of potassium persulfate m 100 ml
of distilled water
6 7 Stock Mercury Solution Dissolve 0 1354 g of mercuric chloride in 75 ml of distilled
water Add 10 ml of cone nitric acid and adjust the volume to 100 0 ml 1 ml = 1 mg
Hg
•BUBBLER
SAMPLE SOLUTION
IN BOD BOTTLE
ABSORPTION
CELL
SCRUBBER
CONTAINING
A MERCURY
ABSORBING
MEDIA
FIGURE 1. APPARATUS FOR FLAMELESS
MERCURY DETERMINATION
245 1-3
-------
6 8 Working Mercury Solution Make successive dilutions of the stock mercury solution to
obtain a working standard containing 0 1 ug per ml This working standard and the
dilutions of the stock mercury solution should be prepared fresh daily Acidity of the
working standard should be maintained at 0 15% nitric acid This acid should be added
to the flask as needed before the addition of the ahquot
7. Calibration
7 1 Transfer 0, 0 5, 1 0, 2 0, 5 0 and 10 0 ml aliquots of the working mercury solution
containing 0 to 1 0 ug of mercury to a series of 300 ml BOD bottles Add enough distilled
water to each bottle to make a total volume of 100 ml Mix thoroughly and add 5 ml of
cone sulfunc acid (6 1) and 2 5 ml of cone nitric acid (6 2) to each bottle Add 15 ml of
KMnO4 (6 5) solution to each bottle and allow to stand at least 15 minutes Add 8 ml of
potassium persulfate (6 6) to each bottle and heat for 2 hours in a water bath maintmed at
95"C Cool and add 6 ml of sodium chloride-hydroxylamine sulfate solution (6 4) to
reduce the excess permanganate When the solution has been decolorized wait 30
seconds, add 5 ml of the stannous sulfate solution (6 3) and immediately attach the bottle
to the aeration apparatus forming a closed system At this point the sample is allowed to
stand quietly without manual agitation The circulating pump, which has previously
been adjusted to a rate of 1 liter per minute, is allowed to run continuously (See Note 4)
The absorbance will increase and reach maximum within 30 seconds As soon as the
recorder pen levels off, approximately 1 minute, open the bypass valve and continue the
aeration until the absorbance returns to its minimum value (see Note 5) Close the bypass
valve, remove the stopper and frit from the BOD bottle and continue the aeration
Proceed with the standards and construct a standard curve by plotting peak height
versus micrograms of mercury
NOTE 4: An open system where the mercury vapor is passed through the absorption cell
only once may be used instead of the closed system
NOTE 5: Because of the toxic nature of mercury vapor precaution must be taken to avoid
its inhalation Therefore, a bypass has been included in the system to either vent the
mercury vapor into an exhaust hood or pass the vapor through some absorbing media,
such as
a) equal volumes of 0 1 M KMnO4 and 10% H2SO4
b) 0 25 % iodine in a 3 % KI solution
A specially treated charcoal that will adsorb mercury vapor is also available from
Barnebey and Cheney, E 8th Ave andN CassidySt, Columbus, Ohio 43219,
Cat #580-13 or #580-22
8 Procedure
8 1 Transfer 100 ml, or an aliquot diluted to 100 ml, containing not more than 1 0 ug of
mercury, to a 300 ml BOD bottle Add 5 ml of sulfunc acid (6 1) and 2 5 ml of cone
nitnc acid (6 2) mixing after each addition Add 15 ml of potassium permanganate
solution (6 5) to each sample bottle For sewage samples additional permanganate may
be required Shake and add additional portions of potassium permanganate solution, if
necessary, until the purple color persists for at least 15 minutes Add 8 ml of potassium
persulfate (6 6) to each bottle and heat for 2 hours in a water bath at 95°C Cool and add 6
245 1-4
-------
ml of sodium chlonde-hydroxylamme sulfate (6 4) to reduce the excess permanganate
After a delay of at least 30 seconds add 5 ml of stannous sulfate (6 3) and immediately
attach the bottle to the aeration apparatus Continue as described under Calibration
Calculation
9 1 Determine the peak height of the unknown from the chart and read the mercury value
from the standard curve
9 2 Calculate the mercury concentration in the sample by the formula
neHR/l= ("ZHZm\ I l$™ \
5 e ^ aliquot I \ volume of aliquot in ml I
9 3 Report mercury concentrations as follows Below 02 ug/1, <02, between 1 and 10
ug/1, one decimal, above 10 ug/1, whole numbers
10 Precision and Accuracy
10 1 In a single laboratory (EMSL), using an Ohio River composite sample with a
background mercury concentration of 0 35 ug/1, spiked with concentrations of 1 0, 3 0
and 4 0 ug/1, the standard deviations were ±0 14, ±0 10 and ±0 08, respectively
Standard deviation at the 0 35 level was ±0 16 Percent recoveries at the three levels
were 89, 87, and 87%, respectively
10 2 In a joint EPA/ASTM interlaboratory study of the cold vapor technique for total
mercury in water, increments of organic and inorganic mercury were added to natural
waters Recoveries were determined by difference A statistical summary of this study
follows
Standard
Number True Values Mean Value Deviation Accuracy as
of Labs Hg/liter ug/liter ug/hter % Bias
76 021 0349 0276 66
80 027 0414 0279 53
82 051 0674 0541 32
77 060 0709 0390 18
82 34 341 149 034
79 41 3 81 1 12 -71
79 88 877 369 -04
78 96 910 357 -52
11 Appendix
111 While the possibility of absorption from certain organic substances actually being present
in the sample does exist, EMSL has not encountered such samples This is mentioned
only to caution the analyst of the possibility A simple correction that may be used is as
follows If an interference has been found to be present (4 4), the sample should be
analyzed both by using the regular procedure and again under oxidizing conditions only,
245 1-5
-------
that is without the reducing reagents The true mercury value can then be obtained by
subtracting the two values
112 If additional sensitivity is required, a 200 ml sample with recorder expansion may be used
provided the instrument does not produce undue noise Using a Coleman MAS-50 with a
drying tube of magnesium perchlorate and a variable recorder, 2 mv was set to read full
scale. With these conditions, and distilled water solutions of mercuric chloride at
concentrations of 015, 0 10, 0 05 and 0 025 ug/1 the standard deviations
were ±0 027, ±0 006, ±0 01 and ±0 004 Percent recoveries at these levels were 107,
83, 84 and 96%, respectively
113 Directions for the disposal of mercury-containing wastes are given m ASTM Standards,
Part 31, "Water", p 349, Method D3223 (1976)
Bibliography
1 Kopp, J F, Longbottom, M C and Lobnng, L B , "Cold Vapor Method for Determining
Mercury", AWWA, vol 64, p 20, Jan, 1972
2 Annual Book of ASTM Standards, Part 31, "Water", Standard D3223-73, p 343 (1976)
3. Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 156 (1975)
245 1-6
-------
MERCURY
Method 245.2 (Automated Cold Vapor Technique)
STORET NO. Total 71900
Dissolved 71890
Suspended 71895
1 Scope and Application
1 1 This method is applicable to surface waters It may be applicable to saline waters,
wastewaters, effluents, and domestic sewages providing potential interferences are not
present (See Interference 4)
1 2 The working range is 0 2 to 20 0 ug Hg/1
2 Summary of Method
2 1 The flameless A A procedure is a physical method based on the absorption of radiation at
253 7 nm by mercury vapor The mercury is reduced to the elemental state and aerated
from solution The mercury vapor passes through a cell positioned in the light path of an
atomic absorption spectrophotometer Absorbance (peak height) is measured as a
function of mercury concentration and recorded in the usual manner
22 In addition to inorganic forms of mercury, organic mercurials may also be present These
organo-mercury compounds will not respond to the flameless atomic absorption
technique unless they are first broken down and converted to mercunc ions Potassium
permanganate oxidizes many of these compounds but recent studies have shown that a
number of organic mercurials, including phenyl mercunc acetate and methyl mercunc
chloride, are only partially oxidized by this reagent Potassium persulfate has been found
to give approximately 100% recovery when used as the oxidant with these compounds
Therefore, an automated persulfate oxidation step following the automated addition of
the permanganate has been included to insure that organo-mercury compounds, if
present, will be oxidized to the mercunc ion before measurement
3 Sample Handling and Preservation
3 1 Until more conclusive data are obtained, samples should be preserved by acidification
with nitric acid to a pH of 2 or lower immediately at the time of collection(1) If only
dissolved mercury is to be determined, the sample should be filtered before the acid is
added For total mercury the filtration is omitted
4 Interference (See NOTE 1)
4 1 Some sea waters and waste-waters high in chlorides have shown a positive interference,
probably due to the formation of free chlorine
4 2 Interference from certain volatile organic materials which will absorb at this wavelength
is also possible A preliminary run under oxidizing conditions, without stannous sulfate,
would determine if this type of interference is present
Approved for NPDES and SDWA
Issued 1974
245 2-1
-------
4 3 Formation of a heavy precipitate, in some wastewaters and effluents, has been reported
upon addition of concentrated sulfunc acid If this is encountered, the problem sample
cannot be analyzed by this method
4 4 Samples containing solids must be blended and then mixed while being sampled if total
mercury vlaues are to be reported
NOTE 1: All the above interferences can be overcome by use of the Manual Mercury
method in this manual
5. Apparatus
5 1 Techmcon Auto Analyzer consisting of
511 Sampler II with provision for sample mixing
5 1 2 Manifold
5.13 Proportioning Pump II or III
514 High temperature heating bath with two distillation coils (Techmcon Part
#116-0163) in series
5 2 Vapor-liquid separator (Figure 1)
5 3 Absorption cell, 100 mm long, 10 mm diameter with quartz windows
5 4 Atomic Absorption Spectrophotometer (See Note 2) Any atomic absorption unit having
an open sample presentation area in which to mount the absorption cell is suitable
Instrument settings recommended by the particular manufacturer should be followed
NOTE 2: Instruments designed specifically for the measurement of mercury using the
cold vapor technique are commercially available and may be substituted for the atomic
absorption Spectrophotometer
5 5 Mercury Hollow Cathode Lamp Westinghouse WL-22847, argon filled, or equivalent
5.6 Recorder Any multi-range variable speed recorder that is compatible with the UV
detection system is suitable
5 7 Source of cooling water for jacketed mixing coil and connector A-7
5 8 Heat lamp A small reading lamp with 60W bulb may be used to prevent condensation of
moisture inside the cell The lamp is positioned to shine on the absorption cell
maintaining the air temperature in the cell about 10°C above ambient
6. Reagents
6 1 Sulfunc Acid, Cone Reagent grade
611 Sulfunc acid, 2 N Dilute 56 ml of cone sulfunc acid to 1 liter with distilled water
612 Sulfunc acid, 10% Dilute 100 ml cone sulfunc acid to 1 liter with distilled water
6 2 Nitnc acid, Cone Reagent grade of low mercury content
621 Nitnc Acid, 05% Wash Solution Dilute 5 ml of cone mtnc acid to 1 liter with
distilled water
6 3 Stannous Sulfate Add 50 g stannous sulfate to 500 ml of 2 N sulfunc acid (6 1 1) This
mixture is a suspension and should be stirred continuously during use
NOTE 3: Stannous chlonde may be used in place of stannous sulfate
6 4 Sodium Chlonde-Hydroxylamme Sulfate Solution Dissolve 30 g of sodium chloride
and 30 g of hydroxylamme sulfate in distilled water to 1 liter
245 2-2
-------
NOTE 4: Hydroxylamme hydrochlonde may be used m place of hydroxylamme sulfate
6 5 Potassium Permanganate 0 5% solution, w/v Dissolve 5 g of potassium permanganate
in 1 liter of distilled water
6 6 Potassium Permanganate, 0 1 N Dissolve 3 16 g of potassium permanganate in distilled
water and dilute to 1 liter
6 7 Potassium Persulfate 05% solution, w/v Dissolve 5 g potassium persulfate in 1 liter of
distilled water
6 8 Stock Mercury Solution Dissolve 0 1354 g of mercuric chloride in 75 ml of distilled
water Add 10 ml of cone nitric acid and adjust the volume to 100 0 ml 1 0 ml = 10
mgHg
6 9 Working Mercury Solution Make successive dilutions of the stock mercury solution
(6 8) to obtain a working standard containing 0 1 ug per ml This working standard and
the dilutions of the stock mercury solution should be prepared fresh daily Acidity of the
working standard should be maintained at 0 15% nitric acid This acid should be added
to the flask as needed before the addition of the aliquot From this solution prepare
standards containing 0 2,0 5,1 0,2 0, 5 0, 10 0, 15 0 and 20 0 ug Hg/1
6 10 Air Scrubber Solution Mix equal volumes of 0 1 N potassium permanganate (6 6) and
10% sulfunc acid (6 1 2)
Procedure
7 1 Set up manifold as shown in Figure 2
7 2 Feeding all the reagents through the system with acid wash solution (6 2 1) through the
sample line, adjust heating bath to 105°C
7 3 Turn on atomic absorption spectrophotometer, adjust instrument settings as
recommended by the manufacturer, align absorption cell in light path for maximum
transmittance and place heat lamp directly over absorption cell
7 4 Arrange working mercury standards from 0 2 to 20 0 ug Hg/1 in sampler and start
sampling Complete loading of sample tray with unknown samples
7 5 Prepare standard curve by plotting peak height of processed standards against
concentration values Determine concentration of samples by comparing sample peak
height with standard curve
NOTE 5: Because of the toxic nature of mercury vapor, precaution must be taken to
avoid its inhalation Venting the mercury vapor into an exhaust hood or passing the
vapor through some absorbing media such as
a) equal volumes of 0 1 N KMnO4 (6 6) and 10% H2SO4 (6 1 2)
b) 0 25% iodine in a 3% KI solution, is recommended
A specially treated charcoal that will adsorb mercury vapor is also available from
Barnebey and Cheney, E 8th Ave and North Cassidy St, Columbus, Ohio 43219,
Cat #580-13 or #580-22
7 6 After the analysis is complete put all lines except the H2SO4 line in distilled water to wash
out system After flushing, wash out the H2SO4 line Also flush the coils in the high
temperature heating bath by pumping stannous sulfate (6 3) through the sample lines
followed by distilled water This will prevent build-up of oxides of manganese
245 2-3
-------
8. Precision and Accuracy
81 In a single laboratory (SEWL), using distilled water standards at concentrations of 0 5,
10, 20, 50, 100 and 200 ug Hg/1, the standard deviations
were ±004, ±007, ±009, ±020, ±040 and ±0 84 ug/1, respectively
82 In a single laboratory (SEWL), using surface water samples spiked with ten organic
mercurials at the 10 ug/1 level, recoveries ranged from 87 to 117% Recovenes of the
same ten organic mercurials m distilled water at the 10 ug/1 level, ranged from 92% to
125%
Bibliography
1 Wallace, R A, Fulkerson, W , Shults, W D , and Lyon, W S , "Mercury in the Environment-
The Human Element", Oak Ridge National Laboratory, ORNL-NSF-EP-1, p 31, (January,
1971)
2 Hatch, W R and Ott, W L, "Determination of Sub-Microgram Quantities of Mercury by
Atomic Absorption Spectrophotometry", Anal Chem 40,2085(1968)
3 Brandenberger, H and Bader, H , "The Determination of Nanogram Levels of Mercury in
Solution by a Flameless Atomic Absorption Technique", Atomic Absorption Newsletter 6^
101 (1967)
4 Brandenberger, H and Bader, H, "The Determination of Mercury by Flameless Atomic
Absorption II, A Static Vapor Method", Atomic Absorption Newsletter 7^53 (1968)
5. Goulden, P D and Afghan, B K, "An Automated Method for Determining Mercury in
Water", Techmcon, Adv in Auto Anal 2,_p 317 (1970)
245 2-4
-------
AIR
OUT
AIR AND
SOLUTION
IN
04 cm ID
7/25
07cm ID
l4cm
SOLUTION
OUT
FIGURE 1. VAPOR LIQUID SEPARATOR
245 2-5
-------
245 2-6
-------
MERCURY IN SEDIMENT
Method 245.5 (Manual Cold Vapor Technique)
Scope and Application
1 1 This procedure"' measures total mercury (organic f inorganic) in soils, sediments,
bottom deposits and sludge type materials
1 2 The range of the method is 0 2 to 5 ug/g The range may be extended above or below the
normal range by increasing or decreasing sample size or through instrument and
recorder control
Summary of Method
21 A weighed portion of the sample is digested in aqua regia for 2 minutes at 95°C, followed
by oxidation with potassium permanganate Mercury m the digested sample is then
measured by the conventional cold vapor technique
22 An alternate digestion"' involving the use of an autoclave is described in (8 2)
Sample Handling and Preservation
3 1 Because of the extreme sensitivity of the analytical procedure and the omnipresence of
mercury, care must be taken to avoid extraneous contamination Sampling devices and
sample containers should be ascertained to be free of mercury, the sample should not be
exposed to any condition in the laboratory that may result in contact or air-borne
mercury contamination
3 2 While the sample may be analyzed without drying, it has been found to be more
convenient to analyze a dry sample Moisture may be driven off in a drying oven at a
temperature of 60°C No mercury losses have been observed by using this drying step
The dry sample should be pulverized and thoroughly mixed before the aliquot is
weighed
Interferences
4 1 The same types of interferences that may occur in water samples are also possible with
sediments, i e , sulfides, high copper, high chlorides, etc
4 2 Volatile materials which absorb at 253 7 nm will cause a positive interference In order to
remove any interfering volatile materials, the dead air space in the BOD bottle should be
purged before the addition of stannous sulfate
Apparatus
5 1 Atomic Absorption Spectrophotometer (See Note 1) Any atomic absorption unit
having an open sample presentation area in which to mount the absorption cell is
suitable Instrument settings recommended by the particular manufacturer should be
followed
NOTE 1 Instruments designed specifically for the measurement of mercury using the
cold vapor technique are commercially available and may be substituted for the atomic
absorption Spectrophotometer
Issued 1974
245 5-1
-------
5 2 Mercury Hollow Cathode Lamp Westmghouse WL-22847, argon filled, or equivalent
5 3 Recorder- Any multi-range variable speed recorder that is compatible with the UV
detection system is suitable
5.4 Absorption Cell Standard spectrophotometer cells 10 cm long, having quartz end
windows may be used Suitable cells may be constructed from plexiglass tubing, 1" O D
X 4-1/2" The ends are ground perpendicular to the longitudinal axis and quartz
windows (1" diameter X 1/16" thickness) are cemented in place Gas inlet and outlet
ports (also of plexiglass but 1/4" O D ) are attached approximately 1/2" from each end
The cell is strapped to a burner for support and aligned in the light beam to give the
maximum transmittance
NOTE 2: Two 2" X 2" cards with one inch diameter holes may be placed over each end
of the cell to assist in positioning the cell for maximum transmittance
5.5 Air Pump Any peristaltic pump capable of delivering 1 liter of air per minute may be
used A Masterflex pump with electronic speed control has been found to be satisfactory
(Regulated compressed air can be used in an open one-pass system )
5 6 Flowmeter Capable of measuring an air flow of 1 liter per minute
5.7 Aeration Tubing Tygon tubing is used for passage of the mercury vapor from the sample
bottle to the absorption cell and return Straight glass tubing terminating in a coarse
porous frit is used for sparging air into the sample
5 8 Drying Tube 6" X 3/4" diameter tube containing 20 g of magnesium perchlorate (See
Note 3) The apparatus is assembled as shown in the accompanying diagram
NOTE 3: In place of the magnesium perchlorate drying tube, a small reading lamp with
60W bulb may be used to prevent condensation of moisture inside the cell The lamp is
positioned to shine on the absorption cell maintaining the air temperature in the cell
about 10°C above ambient
Reagents
6 1 Aqua Regia Prepare immediately before use by carefully adding three volumes of cone
HC1 to one volume of cone HNO3
6 2 Sulfunc Acid, 0 5 N Dilute 14 0 ml of cone sulfunc acid to 1 liter
6 3 Stannous Sulfate Add 25 g stannous sulfate to 250 ml of 0 5 N sulfunc acid (6 2) This
mixture is a suspension and should be stirred continuously during use
6,4 Sodium Chlonde-Hydroxylamme Sulfate Solution Dissolve 12 g of sodium chloride
and 12 g of hydroxylamme sulfate in distilled water and dilute to 100 ml
NOTE 4: A 10% solution of stannous chloride may be substituted for (6 3) and
hydroxylamme hydrochlonde may be used in place of hydroxylamme sulfate in (6 4)
65 Potassium Permanganate 5% solution, w/v Dissolves g of potassium permanganate in
100 ml of distilled water
6 6 Stock Mercury Solution Dissolve 0 1354 g of mercuric chloride in 75 ml of distilled
water Add 10 ml of cone nitric acid and adjust the volume to 100 0 ml 1 0 ml = 10
mgHg
6 7 Working Mercury Solution Make successive dilutions of the stock mercury solution
(6 6) to obtain a working standard containing 0 1 ug/ml This working standard and the
dilution of the stock mercury solutions should be prepared fresh daily Acidity of the
245 5-2
-------
working standard should be maintained at 0 15% nitric acid This acid should be added
to the flask as needed before the addition of the aliquot
Calibration
7 1 Transfer 0, 0 5, 1 0, 2 0, 5 0 and 10 ml ahquots of the working mercury solution (6 7)
containing 0 to 1 0 ug of mercury to a series of 300 ml BOD bottles Add enough distilled
water to each bottle to make a total volume of 10 ml Add 5 ml of aqua regia (6 1) and
heat 2 minutes in a water bath at 95°C Allow the sample to cool and add 50 ml distilled
water and 15 ml of KMnO4 solution (6 5) to each bottle and return to the water bath for
30 minutes Cool and add 6 ml of sodium chlonde-hydroxylamme sulfate solution (6 4)
to reduce the excess permanganate Add 50 ml of distilled water Treating each bottle
individually, add 5 ml of stannous sulfate solution (6 3) and immediately attach the
bottle to the aeration apparatus At this point, the sample is allowed to stand quietly
without manual agitation The circulating pump, which has previously been adjusted to
rate of 1 liter per minute, is allowed to run continuously The absorbance, as exhibited
either on the spectrophotometer or the recorder, will increase and reach maximum
within 30 seconds As soon as the recorder pen levels off, approximately 1 minute, open
the bypass value and continue the aeration until the absorbance returns to its minimum
value (See Note 5) Close the bypass value, remove the fritted tubing from the BOD
bottle and continue the aeration Proceed with the standards and construct a standard
curve by plotting peak height versus microgiams of mercury
NOTE 5: Because of the toxic nature of mercury vapor precaution must be taken to avoid
its inhalation Therefore, a bypass has been included in the system to either vent the
mercury vapor into an exhaust hood or pass the vapor through some absorbing media,
such as
a) equal volumes of 0 1 N KMnO4 and 10% H2SO4
b) 0 25% iodine in a 3% KI solution
A specially treated charcoal that will absorb mercury vapor is also available from
Barnebey and Cheney, E 8th Ave , and North Cassidy St, Columbus, Ohio 43219,
Cat #580-13 or #580-22
Procedure
8 1 Weigh triplicate 0 2 g portions of dry sample and place in bottom of a BOD bottle Add 5
ml of distilled water and 5 ml of aqua regia (6 1) Heat 2 minutes in a water bath at 95°C
Cool, add 50 ml distilled water and 15 ml potassium permanganate solution (6 5) to each
sample bottle Mix thoroughly and place in the water bath for 30 minutes at 95°C Cool
and add 6 ml of sodium chloride-hydroxylamme sulfate (6 4) to reduce the excess
permanganate Add 55 ml of distilled water Treating each bottle individually, add 5 ml
of stannous sulfate (6 3) and immediately attach the bottle to the aeration apparatus
Continue as described under (71)
8 2 An alternate digestion procedure employing an autoclave may also be used In this
method 5 ml of cone H2SO4 and 2 ml of cone HNO3 are added to the 0 2 g of sample 5
ml of saturated KMnO4 solution is added and the bottle covered with a piece of
aluminum foil The samples are autoclaved at 121°C and 15 Ibs for 15 minutes Cool,
make up to a volume of 100 ml with distilled water and add 6 ml of sodium chlonde-
245 5-3
-------
hydroxylamme sulfate solution (6 4) to reduce the excess permanganate Purge the dead
air space and continue as described under (7 1)
9. Calculation
9 1 Measure the peak height of the unknown from the chart and read the mercury value from
the standard curve
9 2 Calculate the mercury concentration in the sample by the formula
.„,„_/_ _ ugHgm the aliquot
ugng/g - wt of the aliquot in gr
aliquot in gms
9 3 Report mercury concentrations as follows Below 0 1 ug/gm, <0 1, between 0 1 and 1
ug/gm, to the nearest 001 ug, between 1 and 10 ug/gm, to nearest 0 1 ug, above 10
ug/gm, to nearest ug
10 Precision and Accuracy
10.1 The following standard deviations on replicate sediment samples were recorded at the
indicated levels, 0 29 ug/g ±0 02 and 0 82 ug/g ±0 03 Recovery of mercury at these
levels, added as methyl mercuric chloride, was 97% and 94%, respectively
Bibliography
1. Bishop, J N, "Mercury in Sediments", Ontano Water Resources Comm, Toronto, Ontario,
Canada, 1971
2 Salma, M , private communication, EPA Cal/Nev Basin Office, Almeda, California
245 5-4
-------
MOLYBDENUM
Method 246.1 (Atomic Absorption, direct aspiration)
STORET No. Total 01062
Dissolved 01060
Suspended 01061
Optimum Concentration Range: 1-40 mg/1 using a wavelength of 313 3 nm
Sensitivity: 0 4 mg/1
Detection Limit: 0 1 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 1 840 g of ammonium molybdate (NH4)6Mo7O24«4H2O
(analytical reagent grade) in deiomzed distilled water and dilute to 1 liter 1 ml = 1 mg
Mo (1000 mg/1)
2 Aluminum nitrate solution Dissolve 139 g aluminum nitrate, A1(NO3)3»9H2O, in 150 ml
of deiomzed distilled water, heat to effect solution Allow to cool and make up to 200 ml
3 Prepare dilutions of the stock molybdenum solution to be used as calibration standards
at the time of analysis The calibration standards should be prepared using the same type
of acid and at the same concentration as will result in the sample to be analyzed either
directly or after processing To each 100 ml of standard and sample alike, add 2 ml of the
aluminum nitrate solution
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 thru 4 1 4 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
Instrumental Parameters (General)
1 Molybdenum hollow cathode lamp
2 Wavelength 3133nm
3 Fuel Acetylene
4 Oxidant Nitrous Oxide
5 Type of flame Fuelnch
Approved for NPDES
Issued 1974
Editorial revision 1978
246 1-1
-------
Analysis Procedure
1 For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Interferences
1 With the recommended nitrous oxide-acetylene flame, interferences of calcium and other
ions may be controlled by adding 1000 mg/1 of a refractory metal such as aluminum
[Anal Chem Acta 44, 437 (1969)] This should be done to both samples and standards
alike
Notes
1 Data to be entered into STORET must be reported as ug/1
2 For concentrations of molybdenum below 0 2 mg/1, the furnace procedure, Method
246 2, is recommended
Precision and Accuracy
1 In a single laboratory (EMSL), using a mixed industrial-domestic waste effluent at
concentrations of 0 30, 15 and 7 5 mg Mo/1, the standard deviations were ±0 007,
±0 02 and ±0 07, respectively Recoveries at these levels were 100%, 96% and 95%,
respectively
246 1-2
-------
MOLYBDENUM
Method 246.2 (Atomic Absorption, furnace technique)
STORET No. Total 01062
Dissolved 01060
Suspended 01061
Optimum Concentration Range: 3-60 ug/1
Detection Limit: 1 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 05% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 05% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-1400°C
3 Atomizing Time and Temp 15sec-2800°C
4 Purge Gas Atmosphere Argon
5 Wavelength 313 3 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure", part 9 3 of the
Atomic Absorption Methods section of this manual
Approved for NPDES
Issued 1978
246 2-1
-------
Notes
1 • The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and pyrolytic
graphite
2 Background correction may be required if the sample contains high dissolved solids
3 The use of nitrogen as a purge gas is not recommended
4. For every sample matrix analyzed, verfication is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
6 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 Precision and accuracy data are not available at this time
246 2-2
-------
NICKEL
Method 249.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01067
Dissolved 01065
Suspended 01066
Optimum Concentration Range: 0 3-5 mg/1 using a wavelength of 232 0 nm
Sensitivity. 015 mg/1
Detection Limit: 0 04 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 4 953 g of nickel nitrate, Ni(NO3)2»6H2O (analytical reagent
grade) in deiomzed distilled water Add 10 ml of cone nitric acid and dilute to 1 liter
with deiomzed distilled water 1 ml = 1 mgNi( 1000 mg/1)
1 Prepare dilutions of the stock nickel solution to be used as calibration standards at the
time of analysis The calibration standards should be prepared using the same type of
acid and at the same concentration as will result in the sample to be analyzed either
directly or after processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 thru 4 1 4 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
Instrumental Parameters (General)
1 Nickel hollow cathode lamp
2 Wavelength 232 0 nm
3, Fuel Acetylene
4 Oxidant Air
5 Type of Flame Oxidizing
Analysis Procedure
1 For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Approved for NPDES
Issued 1974
Editonal revision 1978
249 1-1
-------
Interferences
1 The 352 4 nm wavelength is less susceptible to spectral interference and may be used
The calibration curve is more linear at this wavelength, however, there is some loss of
sensitivity
Notes
1 For levels of nickel below 100 ug/1, either the Special Extraction Procedure, given in
part 9 2 of the Atomic Absorption Methods section or the furnace technique, Method
249 2, is recommended
2 Data to be entered into STORET must be reported as ug/1
3 The heptoxime method may also be used (Standard Methods, 14th Edition, p 232)
Precision and Accuracy
1 In a single laboratory (EMSL), using a mixed industrial-domestic waste effluent at
concentrations of 0 20,1 0 and 5 0 mg Ni/1, the standard deviations were ±0011, ±0 02
and ±004, respectively Recoveries at these levels were 100%, 97% and 93%,
respectively
249 1-2
-------
NICKEL
Method 249.2 (Atomic Absorption, furnace technique)
STORET NO. Total 01067
Dissolved 01065
Suspended 01066
Optimum Concentration Range: 5-50 ug/1
Detection Limit: 1 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to used for "standard additions"
1 3 The calibration standard should be diluted to contain 05% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 05% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30 sec-800°C
3 Atomizing Time and Temp 10sec-2700°C
4 Purge Gas Atmosphere Argon
5 Wavelength 232 0 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and pyrolytic
Approved for NPDES
Issued 1978
249 2-1
-------
graphite Smaller size furnace devices or those employing faster rates of atomization can
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings
2 The use of background correction is recommended
3 Nitrogen may also be used as the purge gas
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
6 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 Precision and accuracy data are not available at this time
249 2-2
-------
OSMIUM
Method 252.1 (Atomic Absorption, direct aspiration)
STORET NO. Total*
Optimum Concentration Range: 2-100 mg/1 using a wavelength of 290 9 nm
Sensitivity: 1 mg/1
Detection Limit: 0 3 mg/1
Preparation of Standard Solution
1 Stock Solution A standard AAS solution of osmium tetroxide, OsO4, 1000 mg/1 m
aqueous matrix is available from Alfa Products, Beverly, Massachusetts 01915
Cat #88084
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared to contain \% (v/v) HNO3 and
l%(v/v)H2SO4
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Transfer a representative 100 ml aliquot of the well mixed sample to a Griffin beaker and
add 1 ml of cone distilled HNO3 Place the beaker on a steam bath or hot plate and warm
for 15 minutes Cool the beaker and filter to remove insoluble material that could clog
the atomizer Add 1 ml of cone H2SO4 and adjust the volume back to 100 ml The sample
is now ready for analysis
Instrumental Parameters (General)
1 Osmium hollow cathode lamp
2 Wavelength 290 9 nm
3 Fuel Acetylene
4 Oxidant Nitrous oxide
5 Type of flame Fuel rich
Analysis Procedure
1 For the analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the
Atomic Absorption Methods section of this manual
*Not Assigned
Approved for NPDES
Issued 1976
Technical revision 1978
252 1-1
-------
Notes
1 Osmium tetroxide, the usual commercial form, is very volatile and highly toxic Care
should be exercised when working with this compound
2 For concentrations of osmium below 0 5 mg/1 the furnace procedure, Method 252 2, is
recommended
Precision and Accuracy
1 Precision and accuracy data are not available at this time
252 1-2
-------
OSMIUM
Method 252.2 (Atomic Absorption, furnace technique)
STORET NO Total*
Optimum Concentration Range. 50-500 ug/1
Dectection Limit 20 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 1 % (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method", except omit the addition of
H2SO4 on the final volume adjustment Sample solutions for analysis should contain 1%
(v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-105°C
2 Ashing Time and Temp See NOTE 3 below
3 Atomizing Time and Temp 10 sec-2700°C
4 Purge Gas Atmosphere Argon
5 Wavelength 290 9 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Notes
1 Osmium tetroxide, the usual commercial form, is very volatile and highly toxic Care
should be exercised when working with this compound
*Not Assigned
Approved for NPDES
Issued 1978
252 2-1
-------
2. The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and non-pyrolytic
graphite
3 Since OSO4 volatilizes near 150°C, the allowable ashing temperature must be verified m
the sample matrix being analyzed
4. The use of background correction is recommended
5 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
6 If method of standard addition is required, follow the procedure given earlier m part 8 5
of the Atomic Absorption Methods section of this manual
Precision and Accuracy
1 Precision and accuracy data are not available at this time
252 2-2
-------
PALLADIUM
Method 253.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01210
Optimum Concentration Range: 05-15 mg/1 using a wavelength of 247 6 nm
Sensitivity. 0 25 mg/1
Detection Limit: 0 1 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 0 1000 g of palladium wire m a minimum volume of aqua regia
and evaporate just to dryness Add 5 ml cone HC1 and 25 ml deiomzed water and warm
until dissolution is complete Dilute to 100 ml with deiomzed water (1 ml = 1 mg Pd)
2 A standard A AS solution of palladous chloride, PdCl2, 1000 mg/1 in aqueous matrix is
available from Alfa Products, Beverly, Massachusetts 01915
Cat #88085
3 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared to contain 05% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Transfer a representative aliquot of the well mixed sample to a Griffin beaker and add 3
ml of cone distilled HNO3 Place the beaker on a steam bath and evaporate to near
dryness Cool the beaker and cautiously add a 5 ml portion of aqua regia (See below for
preparation of aqua regia f) Cover the beaker with a watch glass and return to the steam
bath Continue heating the covered beaker for 30 minutes Remove cover and evaporate
to near dryness Cool and add 1 1 redistilled HNO3 (1 ml per 100 ml dilution) Wash
down the beaker walls and watch glass with distilled water and filter the sample to
remove silicates and other insoluble material that could clog the atomizer Adjust the
volume to some predetermined value based on the expected metal concentration The
sample is now ready for analysis
fAqua regia-prepare immediately before use by carefully adding three volume of
cone HC1 to one volume of cone HNO3
Approved for NPDES
Issued 1976
Technical revision 1978
253 1-1
-------
Instrumental Parameters (General)
1 Palladium hollow cathode lamp
2 Wavelength 247 6 nm
3. Fuel Acetylene
4 Oxidant Air
5 Type of flame Oxidizing
Analysis Procedure
1 For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Notes
1 For concentrations of palladium below 0 25 mg/1, the furnace procedure, Method 253 2,
is recommended
Precision and Accuracy
1 Precision and accuracy data are not available at this time
253 1-2
-------
PALLADIUM
Method 253.2 (Atomic Absorption, furnace technique)
STORET NO. Total 01210
Optimum Concentration Range: 20-400 ug/1
Detection Limit: 5 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 05% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solution for analysis
should contain 0 5%(v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-1000°C
3 Atomizing Time and Temp 10sec-2800°C
4 Purge Gas Atmosphere Argon
5 Wavelength 247 6 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and pyrolytic
graphite Smaller size furnace devices or those employing faster rates of atonuzation can
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings
Approved for NPDES
Issued 1978
253 2-1
-------
2 The use of background correction is recommended
3 Nitrogen may also be used as the purge gas
4. For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
i
Precision and Accuracy
1 Precision and accuracy data are not available at this time
253 2-2
-------
PLATINUM
Method 255.1 (Atomic Absorption, direct aspiration)
STORET NO. Total*
Optimum Concentration Range: 5-75 mg/1 using a wavelength of 265 9 nm
Sensitivity: 2 mg/1
Detection Limit: 0 2 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 0 1000 g of platinum metal in a minimum volume of aqua regia
and evaporate just to dryness Add 5 ml HC1 and 0 1 g NaCl and again evaporate just to
dryness Dissolve the residue in 20 ml of (1 1) HCl and dilute to 100 ml with deiomzed
water (1 ml = ImgPt)
2 A standard AAS solution of chloroplatimc acid, H2PtCl6) 1000 mg/1 in aqueous matrix
is available from Alfa Products, Beverly, Massachusetts 01915
Cat #88086
3 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared to contain 0 5%(v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Transfer a representative aliquot of the well mixed sample to a Griffin beaker and add 3
ml of cone distilled HNO3 Place the beaker on a steam bath and evaporate to near
dryness Cool the beaker and cautiously add a 5 ml portion of aqua regia (See below for
preparation of aqua regia f) Cover the beaker with a watch glass and return to the steam
bath Continue heating the covered beaker for 30 minutes Remove cover and evaporate
to near dryness Cool and add 1 1 distilled HNO3 (1 ml per 100 ml dilution) Wash down
the beaker walls and watch glass with distilled water and filter the sample to remove
silicates and other insoluble material that could clog the atomizer Adjust the volume to
some predetermined value based on the expected metal concentration The sample is now
ready for analysis
fAqua regia-prepare immediately before use by carefully adding three volumes of cone HCl
to one volume of cone HNO3
*Not Assigned
Approved for NPDES
Issued 1976
Technical revision 1978
255 1-1
-------
Instrumental Parameters (General)
1 Platinum hollow cathode lamp
2 Wavelength 265 9 nm
3 Fuel Acetylene
4 Oxidant Air
5 Type of flame Oxidizing
Analysis Procedure
1 For analysis procedure and calculation, see "Direct Aspiration", part 9 1 of the Atomic
Absorption Methods section of this manual
Notes ,
1 For concentrations of platinum below 1.0 mg/1, the furnace procedure, Method 255 2, is
recommended
Precision and Accuracy
1 Precision and accuracy data are not available at this time
255 1-2
-------
PLATINUM
Method 255.2 (Atomic Absorption, furnace technique)
STORET NO. Total*
Optimum Concentration Range: 01-2 mg/1
Detection Limit: 0 02 mg/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 0 5% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 0 5% (v/v)HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-1300°C
3 Atomizing Time and Temp 10sec-2800°C
4 Purge Gas Atmosphere Argon
5 Wavelength 265 9 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and pyrolytic
graphite Smaller size furnace devices or those employing faster rates of atomization can
*Not Assigned
Approved for NPDES
Issued 1978
255 2-1
-------
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings
2 The use of background correction is recommended
3 Nitrogen may also be used as the purge gas
4, For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
Precision and Accuracy
1 Precision and accuracy data are not available at this time
255 2-2
-------
POTASSIUM
Method 258.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 00937
Dissolved 00935
Suspended 00936
Optimum Concentration Range: 01-2 mg/1 using a wavelength of 766 5 nm
Sensitivity: 0 04 mg/1
Detection Limit: 0 01 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 0 1907 g of KC1 (analytical reagent grade), dried at 110°C, in
deiomzed distilled water and make up to 1 liter 1 ml = 0 10 mg K (100 mg/1)
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared using the same type of acid and at
the same concentration as will result in the sample to be analyzed either directly or after
processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 For the analysis of total potassium in domestic and industrial effluents, the procedures
for the determination of total metals as given in parts 413 and 4 1 4 of the Atomic
Absorption Methods section of this manual have been found to be satisfactory
2 For ambient waters, a representative aliquot of a well mixed sample may also be used
directly for analysis If suspended solids are present in sufficient amounts to clog the
nebulizer, the sample may be allowed to settle and the supernatant liquid analyzed
directly
Instrumental Parameters (General)
1 Potassium hollow cathode lamp
2 Wavelength 766 5 nm
3 Fuel Acetylene
4 Oxidant Air
5 Type of flame Slightly oxidizing
Approved for NPDES
Issued 1971
Editorial revision 1974
258 1-1
-------
Analysis Procedure
1 For the analysis procedure and the calculation, see "Direct Aspiration", part 9 1 of the
Atomic Absorption Methods section of this manual
Notes
1 In air-acetylene or other high temperature flames ( > 2800°C), potassium can experience
partial lomzation which indirectly affects absorption sensitivity The presence of other
alkali salts in the sample can reduce this lomzation and thereby enhance analytical
results The lomzation suppressive effect of sodium is small if the ratio of Na to K is
under 10 Any enhancement due to sodium can be stabilized by adding excess sodium
(1000 ug/ml) to both sample and standard solutions If more stringent control of
lomzation is required, the addition of cesium should be considered Reagent blanks
should be analyzed to correct for potassium impurities m the buffer stock
2 The 404 4 nm line may also be used This line has a relative sensitivity of 500
3 To cover the range of potassium values normally observed in surface waters (0 1-20
mg/1), it is suggested that the burner head be rotated A 90° rotation of the burner head
provides approximately one-eighth the normal sensitivity
4. The flame photometric or colonmetnc methods may also be used (Standard Methods,
14th Edition, p 234 & 235)
5 Data to be entered into STORET must be reported as mg/1
Precision and Accuracy
1 In a single laboratory (EMSL), using distilled water samples spiked at concentrations of
1 6 and 6 3 mg K/l The standard deviations were ±0 2 and ±0 5, respectively
Recoveries at these levels were 103% and 102%, respectively
258 1-2
-------
RHENIUM
Method 264.1 (Atomic Absorption, direct aspiration)
* * , i
STORET NO. Total*
Optimum Concentration Range: 50-1000 mg/1 using a wavelength of 346 0 nm
Sensitivity: 15 mg/1
Detection Limit: 5 mg/1
Preparation of Standard Solution
1 Stock solution Dissolve 1 554 g of potassium perrhenate, KReO4, in 200 ml deiomzed
water Dilute to 1 liter with 1% (v/v) H2SO4 (1 ml = 1 mg Re)
2 A standard AAS solution of ammonium perrhenate, NH4ReO4, 1000 mg/1 in aqueous
matrix is available from Alfa Products, Beverly, Massachussetts.01915
Cat #88089
3 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared using 1 % (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see p'art 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Transfer a representative 100 ml aliquot of the well mixed sample to a Griffin beaker and
add 1 ml of cone distilled HNO3 Place the beaker on a steam bath or hot plate and warm
for 15 minutes Cool and filter to remove insoluble material that could clog the atomizer
Adjust the volume back to 100 ml The sample is now ready for analysis
Instrumental Parameters (General)
1 Rhenium hollow cathode lamp
2 Wavelength 346 Onm
3 Fuel Acetylene
4 Oxidant Nitrous Oxide
5 Type of flame Fuel rich
Analysis Procedure
1 For the analysis procedure and the calculation, see "direct aspiration" part 9,1 of the
Atomic Absorption Methods section of this manual
*Not Assigned
Issued 1976
Technical revision 1978
264 1-1
-------
Notes
1 For concentrations of rhenium below 10 mg/1, the furnace procedure, Method 264 2, is
recommended
Precision and Accuracy
1 Precision and accuracy data are not available at this time
264 1-2
-------
RHENIUM
Method 264.2 (Atomic Absorption, furnace technique)
STORET NO. Total*
Optimum Concentration Range 0 5-5 mg/1
Detection Limit 0 2 mg/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standards should be diluted to contain 1 % (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain l%(v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-300°C
3 Atomizing Time and Temp 10 sec-2800°C
4 Purge Gas Atmosphere Argon
5 Wavelength 346 Onm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
*Not Assigned
Issued 1978
264 2-1
-------
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and pyrolytic
graphite
2 Background correction may be required if the sample contains high dissolved solids
3 Since many rhenium compounds volatilize near 300°C, the allowable ashing temperature
should be verified in the sample matrix being analyzed
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
Precision and Accuracy
1 Precision and accuracy data are not available at this time
264 2-2
-------
RHODIUM
Method 265.1 (Atomic Absorption, direct aspiration)
STORET NO. Total*
Optimum Concentration Range: 1-30 mg/1 using a wavelength of 343 5 nm
Sensitivity: 0 3 mg/1
Detection Limit: 0 05 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 0 3768 g of ammonium chlororhodite, (NH4)3RhCl6«H2O, in a
minimum volume of 10% (v/v) HC1 and dilute to 100 ml with 10% HC1 (1 ml = Img
Rh)
2 A standard AAS solution of rhodium trichloride, RhCl3, 1000 mg/1 in aqueous matrix is
available from Alfa Products, Beverly, Massachusetts 01915
Cat #88090
3 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared to contain 05% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Transfer a representative aliquot of the well mixed sample to a Griffin beaker and add 3
ml of cone distilled HNO3 Place the beaker on a steam bath and evaporate to near
dryness Cool the beaker and cautiously add a 5 ml portion of aqua regia (See below for
preparation of aqua regia f) Cover the beaker with a watch glass and return to the steam
bath Continue heating the covered beaker for 30 minutes Remove cover and evaporate
to near dryness Cool and add 1 1 distilled HNO3 (1 ml per 100 ml dilution) Wash down
the beaker walls and watch glass with distilled water and filter the sample to remove
silicates and other insoluble material that could clog the atomizer Adjust the volume to
some predetermined value based on the expected metal concentration The sample is now
ready for analysis
fAqua regia-prepare immediately before use by carefully adding three volumes
of cone HC1 to one volume of cone HNO3
*Not Assigned
Approved for NPDES
Issued 1976
Technical revision 1978
265 1-1
-------
Instrumental Parameters (General)
1 Rhodium hollow cathode lamp
2 Wavelength 343 5 nm
3 Fuel Acetylene
4 Oxidant Air
5. Type of flame Oxidizing
Analysis Procedure
1 For the analysis procedure and the calculation, see "Direct Aspiration", part 9 1 of the
Atomic Absorption Methods section of this manual
Notes
1 For concentrations of rhodium below 0 2 mg/1, the furnace procedure, Method 265 2, is
recommended
Precision and Accuracy
1. Precision and accuracy data are not available at this time
265 1-2
-------
RHODIUM
Method 265.2 (Atomic Absorption, furnace technique)
STORET NO. Total*
Optimum Concentration Range: 20-400 ug/1
Detection Limit: 5 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
, 2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 05% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 05% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-1200°C
3 Atomizing Time and Temp 10sec-2800°C
4 Purge Gas Atmosphere Argon
5 Wavelength 343 5 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
*Not Assigned
Approved for NPDES
Issued 1978
265 2-1
-------
Notes
1. The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and pyrolytic
graphite
2. Background correction may be required if the sample contains high dissolved solids
3 The use of nitrogen as a purge gas is not recommended
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
Precision and Accuracy
1, Precision and accuracy data are not available at this time
265 2-2
-------
RUTHENIUM
> " *
Method 267.1 (Atomic Absorption, direct aspiration)
STORET NO. Total*
> ,
Optimum Concentration Range: 1-50 mg/1 using a wavelength of 349 9 nm
^Sensitivity: 0 5 mg/1
Detection Limit: 0 2 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 0 2052 g of ruthenium chloride, RuCl3, in a minimum volume of
20% (v/v) HC1 and dilute to 100 ml with 20% HC1 (1 ml = 1 mg Ru)
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared using 1 % (v/v) HC1
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Transfer a representative 100 ml aliquot of the well mixed sample to a Griffin beaker and
add 2 ml of distilled (11) HC1 Place the beaker on a steam bath or hot plate and warm at
95°C for 15 minutes Cool the beaker and filter the sample to remove insoluble material
that could clog the atomizer Adjust the volume back to 100 ml The sample is now ready
for analysis
Instrumental Parameters (General)
1 Ruthenium hollow cathode lamp
2 Wavelength 349 9 nm
3 Fuel Acetylene
4 Oxidant Air
5 Type of flame Oxidizing
Analysis Procedure
1 For the analysis procedure and the calculation, see "Direct Aspiration", part 9 1 of the
Atomic Absorption Methods section of this manual
*Not Assigned
Approved for NPDES
Issued 1976
Technical revision 1978
267 1-1
-------
Notes
1 For concentrations of ruthenium below 0 5 mg/1, the furnace procedure, Method 267 2,
is recommended
Precision and Accuracy
1. Precision and accuracy data are not available at this time
267 1-2
-------
RUTHENIUM
Method 267.2 (Atomic Absorption, furnace technique)
STORET NO. Total*
Optimum Concentration Range* 0 1-2 mg/1
Detection Limit. 0 02 mg/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 Using distilled (11) HC1, the calibration standards should be diluted to contain 1 % (v/v)
HC1
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 1% (v/v) HC1
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-^00°C
3 Atomizing Time and Temp 10sec-2800°C
4 Purge Gas Atmosphere Argon
5 Wavelength 349 9 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
*Not Assigned
Approved for NPDES
Issued 1978
267 2-1
-------
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and non-pyrolytic
graphite
2 Background correction may be required if the sample contains high dissolved solids
3. Nitrogen may also be used as the purge gas
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
Precision and Accuracy
1 Precision and accuracy data are not available at this time
267 2-2
-------
SELENIUM
Method 270.2 (Atomic Absorption, furnace technique)
STORET NO. Total 01147
Dissolved 01145
Suspended 01146
Optimum Concentration Range: 5-100 ug/1
Detection Limit: 2 ug/1
Preparation of Standard Solution
1 Stock Selenium Solution Dissolve 0 3453 g of selenous acid (actual assay 94 6% H2SeO3)
in deiomzed distilled water and make up to 200 ml 1 ml — 1 mg Se (1000 mg/1)
2 Nickel Nitrate Solution, 5% Dissolve 24 780 g of ACS reagent grade Ni(NO3)2»6H2O in
deiomzed distilled water and make up to 100 ml
3 Nickel Nitrate Solution, 1% Dilute 20 ml of the 5% nickel nitrate to 100 ml with
deiomzed distilled water
4 Working Selenium Solution Prepare dilutions of the stock solution to be used as
calibration standards at the time of analysis Withdraw appropriate aliquots of the stock
solution, add 1 ml of cone HNO3, 2 ml of 30% H2O2 and 2 ml of the 5% nickel nitrate
solution Dilute to 100 ml with deiomzed distilled water
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Transfer 100 ml of well-mixed sample to a 250 ml Griffin beaker, add 2 ml of 30% H2O2
and sufficient cone HNO3 to result in an acid concentration of 1 %(v/v) Heat for 1 hour
at 95°C or until the volume is slightly less than 50 ml
2 Cool and bring back to 50 ml with deiomzed distilled water
3 Pipet 5 ml of this digested solution into a 10-ml volumetric flask, add 1 ml of the 1%
nickel nitrate solution and dilute to 10 ml with deiomzed distilled water The sample is
now ready for injection into the furnace NOTE If solubihzation or digestion is not
required adjust the HNO3 concentration of the sample to 1% (v/v) and add 2 ml of 30%
H2O2 and 2 ml of 5% nickel nitrate to each 100 ml of sample The volume of the
calibration standard should be adjusted with deiomzed distilled water to match the
volume change of the sample
Approved for NPDES and SDWA
Issued 1978
270 2-1
-------
Instrument Parameters
1 Drying time and temperature 30 sec® 125°C
2 Charring time and temperature 30 see® 1200°C
3. Atomizing time and temperature 10 sec @ 2700°C
4 Purge Gas Atmosphere Argon , • , > '
5 Wavelength 196 Onm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer '
Analysis Procedure
1 For the analysis procedure and the calculation see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Notes
1. The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, purge gas interrupt and non-pyrolytic
graphite Smaller size furnace devices or those employing faster rates of atomization can
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings
2. The use of background correction is recommended
3 Selenium analysis suffers interference from chlorides (> 800 mg/1) and sulfate (> 200
mg/1) For the analysis of industrial effluents and samples with concentrations of sulfate
from 200 to 2000 mg/1, both samples and standards should be prepared to contain 1%
nickel
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 For quality control requirements and optional recommendations for use in drinking
water analyses, see part 10 of the Atomic Absorption Methods section of this manual
6 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
7 Data to entered into STORET must be reported as ug/1
Precision and Accuracy
1 Using a sewage treatment plant effluent containing <2 ug/1 and spiked with a
concentration of 20 ug/1, a recovery of 99% was obtained
2 Using a series of industrial waste effluents spiked at a 50 ug/1 level, recoveries ranged
from 94 to 112%
3 Using a 0 1% nickel nitrate solution as a synthetic matrix with selenium concentrations
of 5, 10, 20, 40, 50, and 100 ug/1, relative standard deviations of 14 2, 11 6, 9 3, 7 2, 6 4
and 41%, respectively, were obtained at the 95% confidence level
270 2-2
-------
4 In a single laboratory (EMSL), using Cincinnati, Ohio tap water spiked at concentrations
of 5, 10, and 20 ug Se/1, the standard deviations were ±06, ±04, and ±05,
respectively Recoveries at these levels were 92%, 98%, and 100%, respectively
Reference:
"Determining Selenium in Water, Wastewater, Sediment and Sludge By Flameless Atomic
Absorption Spectroscopy", Martin, T D , Kopp, J F and Ediger, R D Atomic Absorption
Newsletter 14,109 (1975)
270 2-3
-------
SELENIUM
Method 270.3 (Atomic Absorption, gaseous hydride)
STORET NO. Total 01147
Dissolved 01145
Suspended 01146
Scope and Application
1 1 The gaseous hydride method determines inorganic selenium when present in
concentrations at or above 2 ug/1 The method is applicable to drinking water and most
fresh and saline waters, in the absence of high concentrations of chromium, cobalt,
copper, mercury, molybdenum, nickel and silver
Summary of Method
2 1 Selenium in the sample is reduced from the + 6 oxidation state to the +4 oxidation state
by the addition of SnCl2 Zinc is added to the acidified sample, producing hydrogen and
converting the selenium to the hydride, SeH2 The gaseous selenium hydride is swept into
an argon-hydrogen flame of an atomic absorption spectrophotometer The working
range of the method is 2-20 ug/1 using the 196 0 nm wavelength
Comments
31 In analyzing drinking water and most surface and ground waters, interferences are rarely
encountered Industrial waste samples should be spiked with a known amount of
selenium to establish adequate recovery
3 2 Organic forms of selenium must be converted to an inorganic form and organic matter
must be oxidized before beginning the analysis The oxidation procedure given in method
206 5 (Standard Methods, 14th Ed 404B, p 285, Procedure 4 1) should be used
3 3 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
3 4 For quality control requirements and optional recommendations for use in drinking
water analyses, see part 10 of the Atomic Absorption Methods section of this manual
35 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
4 1 Ten replicate solutions of selenium oxide at the 5, 10 and 15 ug/1 level were analyzed by
a single laboratory Standard deviations at these levels were ±06, ±11 and ±2 9 with
recoveries of 100, 100 and 101% (Caldwell, J S , Lishka, R J, and McFarren, E F ,
"Evaluation of a Low-Cost Arsenic and Selenium Determination at Microgram per Liter
Levels", JAWWA,vol 65, p 731,Nov 1973)
Approved for NPDES and SDWA
Issued 1974
270 3-1
-------
5. References
5.1 Except for the perchloric acid step, the procedure to be used for this determination is
found in
Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 159,
Method 301A(VII), (1975)
270 3-2
-------
SILVER
Method 272.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01077
Dissolved 01075
Suspended 01076
Optimum Concentration Range: 0 1-4 mg/1 using a wavelength of 328 1 nm
Sensitivity: 0 06 mg/1
Detection Limit: 001 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 1 575 g of AgNO3 (analytical reagent grade) in deiomzed
distilled water, add 10 ml cone HNO3 and make up to 1 liter 1 ml = 1 mg Ag (1000
mg/1)
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared using nitric acid and at the same
concentration as will result in the sample to be analyzed either directly or after
processing
3 Iodine Solution, 1 N Dissolve 20 grams of potassium iodide, KI (analytical reagent
grade) in 50 ml of deiomzed distilled water, add 127 grams of iodine, I2 (analytical
reagent grade) and dilute to 100 ml Store in a brown bottle
4 Cyanogen Iodide (CNI) Solution To 50 ml of deiomzed distilled water add 4 0 ml cone
NH4OH, 6 5 grams KCN, and 5 0 ml of 1 0 NI2 solution Mix and dilute to 100 ml with
deiomzed distilled water Fresh solution should be prepared every two weeks a)
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 thru 4 1 3 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory,
however, the residue must be taken up in dilute nitric acid rather than hydrochloric to
prevent precipitation of AgCl
Approved for NPDES and SDWA
Issued 1971
Editorial revision 1974
Technical revision 1978
272 1-1
-------
Instrumental Parameters (General)
1. Silver hollow cathode lamp
2. Wavelength 328 1 nm
3 Fuel Acetylene
4 Oxidant Air
5 Type of flame Oxidizing
Analysis Procedure
1 For the analysis procedure and the calculation, see "Direct Aspiration", part 9 1 of the
Atomic Absorption Methods section of this manual
Notes
1 For levels of silver below 30 ug/1, either the Special Extraction Procedure, given in part
9 2 of the Atomic Absorption Methods section or the furnace procedure, Method 272 2,
is recommended
2 Silver nitrate standards are light sensitive Dilutions of the stock should be discarded
after use as concentrations below 10 mg/1 are not stable over long periods of time
3 If absorption to container walls or the formation of AgCl is suspected, make the sample
basic using cone NH4OH and add 1 ml of (CNI) solution per 100 ml of sample Mix the
sample and allow to stand for 1 hour before proceeding with the analysis (1)
4 The 338 2 nm wavelength may also be used This has a relative sensitivity of 2
5 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 In a round-robin study reported by Standard Methods, a synthetic sample containing 50
ug Ag/1 was analyzed by 50 laboratories with a reported standard deviation of ±8 8 and
a relative error 10 6%
References
1. "The Use of Cyanogen Iodide (CNI) as a Stabilizing Agent for Silver in Photographic
Processing Effluent Sample", Owerbach, Daniel, Photographic Technology Division,
Eastman Kodak Company, Rochester, N Y 14650
2 Standard Methods for Examination of Water and Wastewater, 14th Edition, p 148,
Method 301A
272 1-2
-------
SILVER
Method 272.2 (Atomic Absorption, furnace technique)
STORET NO. Total 01077
Dissolved 01075
Suspended 01076
Optimum Concentration Range: 1-25 ug/1
Detection Limit: 0 2 ug/1
Preparation of Standard Solution
1 Stock Solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 05% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 0 5% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-400°C
3 Atomizing Time and Temp 10sec-2700°C
4 Purge Gas Atmosphere Argon
5 Wavelength 328 1 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Approved for NPDES and SDWA
Issued 1978
272 2-1
-------
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and non-pyrolytic
graphite Smaller size furnace devices or those employing faster rates of atomization can
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings
2 Background correction may be required if the sample contains high dissolved solids
3 The use of hahde acids should be avoided
4 If adsorption to container walls or formation of AgCl is suspected, see NOTE 3 under the
Direct Aspiration Method 272 1
5 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
6 For quality control requirements and optional recommendations for use in drinking
water analyses, see part 10 of the Atomic Absorption Methods section of this manual
7 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
8 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy:
1. In a single laboratory (EMSL), using Cincinnati, Ohio tap water spiked at concentrations
of 25, 50, and 75 ug Ag/1, the standard deviations were ±04, ±07, and +09,
respectively Recoveries at these levels were 94%, 100% and 104%, respectively
272 2-2
-------
SODIUM
Method 273.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 00929
Dissolved 00930
Suspended 00928
Optimum Concentration Range 0 03-1 mg/1 using a wavelength of 589 6 nm
Sensitivity 0015 mg/1
Detection Limit 0 002 mg/1
Preparation of Standard Solutions
1 Stock Solution Dissolve 2 542 g of NaCl (analytical reagent grade), dried at 140°C, in
deiomzed distilled water and make up to 1 liter 1 ml = 1 mg Na (1000 mg/1)
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared using the same type of acid and at
the same concentration as will result in the sample to be analyzed either directly or after
processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 For the analysis of total sodium in domestic and industrial effluents, the procedures for
the determination of total metals as given in parts 413 and 4 1 4 of the Atomic
Absorption Methods section of this manual have been found to be satisfactory
2 For ambient waters, a representative aliquot of a well-mixed sample may be used directly
for analysis If suspended solids are present in sufficient amounts to clog the nebulizer,
the sample may be allowed to settle and the supernatant liquid analyzed directly
Instrumental Parameters (General)
1 Sodium hollow cathode lamp
2 Wavelength 589 6 nm
3 Fuel Acetylene
4 Oxidant Air
5 Type of flame Oxidizing
Approved for NPDES
Issued 1971
Editorial revision 1974
273 1-1
-------
Analysis Procedure
1 For the analysis procedure and the calculation, see "Direct Aspiration", part 9 1 of the
Atomic Absorption Methods, section of this manual
Notes
1 The 330 2 nm resonance line of sodium, which has a relative sensitivity of 185, provides a
convenient way to avoid the need to dilute more concentrated solutions of sodium
2 Low-temperature flames increase sensitivity by reducing the extent of lomzation of this
easily ionized metal lomzation may also be controlled by adding potassium (1000 mg/1)
to both standards and samples
3 Data to be entered into STORET must be reported as mg/1
4 The flame photometric method may also be used (Standard Methods, 14th Edition, p
250)
Precision and Accuracy
1 In a single laboratory (EMSL), using distilled water samples spiked at levels of 8 2 and 52
mgNa/1, the standard deviations were ±0 1 and ±0 8, respectively Recoveries at these
levels were 102% and 100%
273 1-2
-------
United States
Environmental Protection
Agency
Environmental Monitoring and
Support Laboratory
Cincinnati OH 45268
Research and Development
vvEPA
Test Method
Sodium (Atomic
Absorption, furnace
technique)—Method 273.2
Optimum Concentration Range 1-30
/"9/L
Detection Limit 0 2 /yg/L
Preparation of Standard Solution
1 Stock solution Prepare as
described under direct
aspiration method
2 Prepare dilutions of the stock
solution to be used as calibration
standards at the time of analysis
These solutions are also to be
used for standard additions
3 The calibration standard should
be diluted to contain 0 5% (v/v)
HNO3
Sample Preservation
1 For sample handling and preser-
vation see part 4 1 of the Atomic
Absorption Methods section of
this manual
Sample Preparation
1 Prepare as described under di-
rect aspiration method Sample
solutions for analysis should
contain 0 5% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30 sec @
125°C
2 Ashing Time and Temp 30 sec @
250°C
3 Atomizing Time and Temp 10 sec
@ 2000°C
4 Purge Gas atmosphere Argon
5 Wavelength 589 6 nm
6 Other operating parameters
should be set as specified by the
particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and
the calculation, see Furnace
Procedure 9 3 of the Atomic
Absorption method section of
this manual
Notes
1 The above concentration values
and instrument conditions are
for a Perkm-Elmer HGA-2100
based on the use of a 20 fjL
injection continuous flow purge
gas and non-pyrolytic graphite
Smaller size furnace devices or
those employing faster rates of
atomization can be operated
using lower atomization
temperatures for shorter time
periods than the above
recommended settings
2 Samples containing
concentrations higher than those
given in the optimum range
should be analyzed by either the
direct aspiration method (Method
273 1) or the flame photometric
method (Std Methods 14th
Edition p 250)
3 Nitrogen may also be used as
the purge gas
4 For every sample matrix
analyzed, verification is
necessary to determine that
method of standard addition is
not required (see 5 2 1 of
the Atomic Absorption method
section of this manual)
5 If method of standard addition is
required follow the procedure
given earlier in 8 5 of the
Atomic Absorption methos
section of this manual
2732 1
Dec 1982
-------
6 Data to be entered into STORE!
must be reported as //g/L
Precision and Accuracy
1 Precision and accuracy data are
not available at this time
Dec 1982 2732-2
-------
THALLIUM
Method 279.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01059
Dissolved 01057
Suspended 01058
Optimum Concentration Range. 1-20 mg/1 using a wavelength of 276 8 nm
Sensitivity 0 5 mg/1
Detection Limit. 0 1 mg/1
Preparation of Standai d Solution
1 Stock Solution Dissolve 1 303 g of thallium nitrate, T1NO3 (analytical reagent grade) m
deiomzed distilled water Add 10 ml of cone nitric acid and dilute to 1 liter with
deiomzed distilled water 1ml = 1 mgTl( 1000 mg/1)
2 Prepare dilutions of the stock thallium solution to be used as calibration standards at the
time of analysis The calibration standards should be prepared using nitric acid and at the
same concentration as will result in the sample to be analyzed either directly or after
processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 4 1 1 thru 4 1 4 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory if
HC1 is omitted
Instrumental Parameters (General)
1 Thallium hollow cathode lamp
2 Wavelength 276 8 nm
3 Fuel Acetylene
4 Oxidant Air
5 Type of flame Oxidizing
Approved for NPDES
Issued 1974
Technical revision 1978
279 1-1
-------
Analysis Procedure
1 For the analysis procedure and the'calculation, see "Direct Aspiration", part 9 1 of the
Atomic Absorption Methods section of this manual
" i t i J ' l
Notes
1 For concentrations of thallium below 0 2 mg/1, the furnace procedure, Method 279 2, is
recommended
2 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 In a single laboratory (EMSL), using a mixed industrial-domestic waste effluent at
concentrations of 0 60, 3 0 and 15 mg Tl/1, the standard deviations were ±0 018, ±6 05
and ±02, respectively Recoveries at these levels were 100%, 98% and 98%,
respectively
279 1-2
-------
THALLIUM
Method 279.2 (Atomic Absorption, furnace technique)
STORET NO. Total 01059
Dissolved 01057
Suspended 01058
Optimum Concentration Range: 5-100 ug/1
Detection Limit: 1 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 05% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 05% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30 sec® 125°C
2 Ashing Time and Temp 30 sec @ 400°C
3 Atomizing Time and Temp 10 sec @ 2400°C
4 Purge Gas Atmosphere Argon
5 Wavelength 276 8 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Approved for NPDES
Issued 1978
279 2-1
-------
Notes
1 The above concentration values and instrument conditions are for a, Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and non-pyrolytic
graphite Smaller size furnace devices or those employing faster rates of atomization can
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings
2 The use of background correction is recommended
3 Nitrogen may also be used as the purge gas
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
6 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 Precision and accuracy data are not available at this time
279 2-2
-------
TIN
Method 282.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01102
Dissolved 01100
Suspended 01101
Optimum Concentration Range: 10-300 mg/1 using a wavelength of 286 3 nm
Sensitivity. 4mg/l
Detection Limit 0 8 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 1 000 g of tin metal (analytical reagent grade) in 100 ml of cone
HC1 and dilute to 1 liter with deiomzed distilled water 1 ml = 1 mg Sn (1000 mg/1)
2 Prepare dilutions of the stock tin solution to be used as calibration standards at the time
of analysis The calibration standards should be prepared using the same type of acid and
at the same concentration as will result in the sample to be analyzed either directly or
after processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 thru 4 1 4 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
Instrumental Parameters (General)
1 Tin hollow cathode lamp
2 Wavelength 286 3 nm
3 Fuel Acetylene
4 Oxidant Nitrous Oxide
5 Type of flame Fuel rich
Analysis Procedure
1 For the analysis procedure and the calculation, see "Direct Aspiration", part 9 1 of the
Atomic Absorption Methods section of this manual
Approved for NPDES
Issued 1974
Editorial revision 1978
282 1-1
-------
Notes
1 For concentrations of tin below 2 mg/1, the furnace procedure, Method 282 2, is
recommended
2 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 In a single laboratory (EMSL), using a mixed industrial-domestic waste effluent spiked
at concentrations of 4 0, 20 and 60 mg Sn/1, the standard deviations were ±0 25, ±0 5
and ±05, respectively Recoveries at these levels were 96%, 101%, and 101%,
respectively
282 1-2
-------
TIN
Method 282.2 (Atomic Absorption, furnace technique)
STORET NO. Total 01102
Dissolved 01100
Suspended 01101
Optimum Concentration Range:
Detection Limit: 5 ug/1
20-300 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 2% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 4 1 1 thru 4 1 3 of the
Atomic Absorption Methods section of this manual should be followed including the
addition of sufficient 1 1 HC1 to dissolve the digested residue for the analysis of
suspended or total tin The sample solutions used for analysis should contain 2% (v/v)
HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-600°C
3 Atomizing Time and Temp 10sec-2700°C
4 Purge Gas Atmospere Argon
5 Wavelength 224 6 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Approved for NPDES
Issued 1978
282 2-1
-------
Notes
1 The above concentration values and instrument conditions are for a Perkin-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and non-pyrolytic
graphite Smaller size furnace devices or those employing faster rates of atomization can
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings
2 The use of background correction is recommended
3 Nitrogen may also be used as the purge gas
4 Tin analysis is sensitive to chloride concentration If chloride concentration presents a
matrix problem or causes a loss previous to atomization, add an excess of 5 mg of
ammonium nitrate to the furnace and ash using a ramp necessary or with incremental
steps until the recommended ashing temperature is reached Extended ashing times have
been reported to improve precision
5. For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
6 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
7 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 Precision and accuracy data are not available at this time
282 2-2
-------
TITANIUM
Method 283.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01152
Dissolved 01150
Suspended 01151
Optimum Concentration Range: 5-100 mg/1 using a wavelength of 365 3 nm
Sensitivity: 2 mg/1
Detection Limit: 0 4 mg/1
Preparation of Standard Solution
1 Stock solution Dissolve 1 000 g of titanium metal (powder or small pieces) in 200 ml
6N HC1 Heat to near 100olC|to effect dissolution Cool and dilute to 1 liter with
deiomzed distilled water (1 ml = 1 mg Ti (1000 mg/1)
2 Potassium chloride solution Dissolve 95 g potassium chloride, KC1, in distilled water
and make up to 1 liter
3 Prepare dilutions of the stock titanium solution to be used as calibration standards at the
time of analysis The calibration standards should be prepared using the same type of
acid and at the same concentration as will result m the sample to be analyzed either
directly or after processing To each 100 ml of standard and sample alike, add 2 ml of
potassium chloride solution
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 thru 4 1 3 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
with the following modification For processing total and suspended titanium,
concentrated H2SO4 (2 ml per 100 ml of final dilution) must be added m addition to the
nitric acid Reflux the sample adding additional nitric acid as needed When
solubilization is complete, heat until the appearance of SO3 fumes Cool and add
sufficient distilled nitric acid so that the final dilution contains 05% (v/v) HNO3
Instrumental Parameters (General)
1 Titanium hollow cathode lamp
2 Wavelength 365 3 nm
3 Fuel Acetylene
Approved for NPDES
Issued 1974
283 1-1
-------
4 Oxidant Nitrous Oxide
5 Type of flame Fuel rich
( i f \
Analysis Procedure
1. For the analysis procedure and the calculation, see "Direct Aspiration" part 9 1 of the
Atomic Absorption Methods section of this manual
Interferences
1 A number of elements increase the sensitivity of titanium To control this problem,
potassium (1000 mg/1) must be added to standards and samples alike [Atomic
Absorption Newsletter 6,_p 86 (1967)]
Notes
1 For concentrations of titanium below 1 0 mg/1, the furnace procedure, Method 283 2, is
recommended
2. Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 In a single laboratory (EMSL), using a mixed industrial-domestic waste effluent spiked
at concentrations of 2 0, 10 and 50 mg Ti/1, the standard deviations were ±0 07, ±0 1
and ±0 4, respectively Recovenes at these levels were 97%, 91% and 88%, respectively
283 1-2
-------
TITANIUM
Method 283.2 (Atomic Absorption, furnace technique)
STORET NO. Total 01152
Dissolved 01150
Suspended 01151
Optimum Concentration Range: 50-500 ug/1
Detection Limit: 10 ug/1
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis
3 The calibration standards should be prepared using the same type of acid and at the same
concentration as will result in the sample to be analyzed either directly or after
processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solutions for analysis
should contain 05% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-1400°C
3 Atomizing Time and Temp 15 sec-2800°C
4 Purge Gas Atmosphere Argon
5 Wavelength 365 4 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Approved for NPDES
Issued 1978
283 2-1
-------
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and pyrolytic
graphite
2 Background correction may be required if the sample contains high dissolved solids
3 Because of possible chemical interactions, nitrogen should not be used as the purge gas
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
6. Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 Precision and accuracy data are not available at this time
283 2-2
-------
VANADIUM
f ^
Method 286.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01087
Dissolved 01085
Suspended 01086
Optimum Concentration Range: 2-100 mg/1 using a wavelength of 318 4 nm
Sensitivity: 0 8 mg/1
Detection Limit* 0 2 mg/1
Preparation of Standard Solution
1 Stock Solution Dissolve 1 7854 g of vanadium pentoxide, V2O5 (analytical reagent
grade) in 10 ml of cone nitric acid and dilute to 1 liter with deiomzed distilled water 1
ml = ImgV (1000 mg/1)
2 Aluminum nitrate solution Dissolve 139 g aluminum nitrate, A1(NO3)3«9H2O, in 150 ml
of deiomzed distilled water, heat to effect solution Allow to cool and make up to 200 ml
3 Prepare dilutions of the stock vanadium solution to be used as calibration standards at
the time of analysis The calibration standards should be prepared using the same type of
acid and at the same concentration as will result in the sample to be analyzed either
directly or after processing To each 100 ml of standard and sample alike, add 2 ml of the
aluminum, nitrate solution
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 411 thru 4 1 4 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
Instrumental Parameters (General)
1 Vanadium hollow cathode lamp
2 Wavelength 3184nm
3 Fuel Acetylene
4 Oxidant Nitrous oxide
5 Type of flame Fuel rich
Approved for NPDES
Issued 1974
286 1-1
-------
Analysis Procedure
1 For the analysis procedure and the calculation, see "Direct Aspiration" part 9 1 of the
Atomic Absorption Methods section of this manual
Interferences
1 It has been reported that high concentrations of aluminum and titanium increase the
sensitivity of vanadium This interference can be controlled by adding excess aluminum
(1000 ppm) to both samples and standards [Talanta^S, 871 (1968)]
Notes
1 For concentrations of vanadium below 0 5 mg/1, the furnace procedure, Method 286 2,
is recommended
2 The gallic acid colonmetnc method may also be used (Standard Methods, 14th Edition,
p260)
3 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 In a single laboratory (EMSL), using a mixed industrial-domestic waste effluent spiked
at concentrations of 2 0, 10 and 50 mg V/l, the standard deviations were ±0 10, ±0 1
and ±02, respectively Recoveries at these levels were 100%, 95% and 97%,
respectively
286 1-2
-------
I i
VANADIUM
' j
Method 286.2 (Atonic Absorption, furnace technique)
STORET NO. Total 01087
' Dissolved 01085
Suspended 01086
Optimum Concentration Range: 10-200 ug/l
Detection Limit: 4 ug/l
' i f
Preparation of Standard Solution
1 Stock solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be, diluted to contain 05% (v/v) HNO3
?
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solution for analysis
should contain 05% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-1400°C
3 Atomizing Time and Temp 15sec-2800°C
4 Purge Gas Atmosphere Argon
5 Wavelength 318 4 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Approved for NPDES
Issued 1978
286 2-1
-------
Notes
1 The above concentration values and instrument conditions are for a Perkm-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and pyrolytic
graphite Smaller size furnace devices or those employing faster rates of atomization can
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings
2 Background correction may be required if the sample contains high dissolved solids
3 Because of possible chemical interaction, nitrogen should not be used as the purge gas
4 For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
5 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
6 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 Precision and accuracy data are not available at this time
286 2-2
-------
ZINC
Method 289.1 (Atomic Absorption, direct aspiration)
STORET NO. Total 01092
Dissolved 01090
Suspended 01091
Optimum Concentration Range: 0 05-1 mg/1 using a wavelength of 213 9 nm
Sensitivity: 0 02 mg/1
Detection Limit: 0 005 mg/1
Preparation of Standard Solution
1 Stock Solution Carefully weigh 1 00 g of zinc metal (analytical reagent grade) and
dissolve cautiously in 10 ml HNO3 When solution is complete make up to 1 liter with
deiomzed distilled water 1 ml = 1 mg Zn (1000 mg/1)
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis The calibration standards should be prepared using the same type of acid and at
the same concentration as will result in the sample to be analyzed either directly or after
processing
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 The procedures for preparation of the sample as given in parts 4 1 1 thru 4 1 4 of the
Atomic Absorption Methods section of this manual have been found to be satisfactory
Instrumental Parameters
1 Zinc hollow cathode lamp
2 Wavelength 213 9 nm
3 Fuel Acetylene
4 Oxidant Air
5 Type of flame Oxidizing
Analysis Procedure
1 For the analysis procedure and the calculation, see "direct aspiration" part 9 1 of the
Atomic Absorption Methods section of this manual
Approved for NPDES
Issued 1971
Editorial revision 1974
289 1-1
-------
Notes
1 High levels of silicon may interfere
2 The air-acetylene flame absorbs about 25% of the energy at the 2139 nm line
3 The sensitivity may be increased by the use of low-temperature flames
4 Some sample container cap liners can be a source of zinc contamination To circumvent
or avoid this problem, the use of polypropylene caps is recommended
5 The dithizone colonmetnc method may also be used (Standard Methods, 14th Edition, p
265)
6 For concentrations of zinc below 001 mg/1, either the Special Extraction Procedure
given in part 9 2 of the Atomic Absorption Methods section or the furnace procedure,
Method 289 2, is recommended
7 Data to entered into Storet must be reported as ug/1
Precision and Accuracy
1. An mterlaboratory study on trace metal analyses by atomic absorption was conducted by
the Quality Assurance and Laboratory Evaluation Branch of EMSL Six synthetic
concentrates containing varying levels of aluminum, cadmium, chromium, copper, iron,
manganese, lead and zinc were added to natural water samples The statistical results for
zinc were as follows
Number
of Labs
86
89
82
81
62
61
True Values
ug/hter
281
310
56
70
7
11
Mean Value
ug/hter
284
308
62
75'
22
17
Standard
Deviation
ug/hter
97
114
28
28
26
18
Accuracy as
% Bias
12
-07
113
66
206
566
289 1-2
-------
ZINC
Method 289.2 (Atomic Absorption, furnace technique)
STORET NO. Total 01092
Dissolved 01090
Suspended 01091
Optimum Concentration Range: 0 2-4 ug/1
Detection Limit: 0 05 ug/1
Preparation of Standard Solution
1 Stock Solution Prepare as described under "direct aspiration method"
2 Prepare dilutions of the stock solution to be used as calibration standards at the time of
analysis These solutions are also to be used for "standard additions"
3 The calibration standard should be diluted to contain 05% (v/v) HNO3
Sample Preservation
1 For sample handling and preservation, see part 4 1 of the Atomic Absorption Methods
section of this manual
Sample Preparation
1 Prepare as described under "direct aspiration method" Sample solution for analysis
should contain 05% (v/v) HNO3
Instrument Parameters (General)
1 Drying Time and Temp 30sec-125°C
2 Ashing Time and Temp 30sec-400°C
3 Atomizing Time and Temp 10sec-2500°C
4 Purge Gas Atmosphere Argon
5 Wavelength 2139 nm
6 Other operating parameters should be set as specified by the particular instrument
manufacturer
Analysis Procedure
1 For the analysis procedure and the calculation, see "Furnace Procedure" part 9 3 of the
Atomic Absorption Methods section of this manual
Approved for NPDES
Issued 1978
289 2-1
-------
Notes
1 The above concentration values and instrument conditions are for a Perkin-Elmer HGA-
2100, based on the use of a 20 ul injection, continuous flow purge gas and non-pyrolytic
graphite Smaller size furnace devices or those employing faster rates of atonuzation can
be operated using lower atomization temperatures for shorter time periods than the
above recommended settings
2 The use of background correction is recommended
3 Nitrogen may also be used as the purge gas
4. The analysis of zinc by the graphite furnace is extremely sensitive and very subject to
contamination from the work area, reagents, and pipet tips Since all these factors affect
the precision and accuracy, zinc should be analyzed by the direct aspiration procedure
whenever possible
5. For every sample matrix analyzed, verification is necessary to determine that method of
standard addition is not required (see part 5 2 1 of the Atomic Absorption Methods
section of this manual)
6 If method of standard addition is required, follow the procedure given earlier in part 8 5
of the Atomic Absorption Methods section of this manual
7 Data to be entered into STORET must be reported as ug/1
Precision and Accuracy
1 Precision and accuracy data are not available at this time
289 2-2
-------
ACIDITY
Method 305.1 (Titrimetric)
STORET NO. 70508
Scope and Application
1 1 This method is applicable to surface waters, sewages and industrial wastes, particularly
mine drainage and receiving streams, and other waters containing ferrous iron or other
polyvalent cations in a reduced state
1 2 The method covers the range from approximately 10 mg/1 acidity to approximately
1000 mg/1 as CaCO3, using a 50 ml sample
Summary of Method
2 1 The pH of the sample is determined and a measured amount of standard acid is added, as
needed, to lower the pH to 4 or less Hydrogen peroxide is added, the solution boiled for
several minutes, cooled, and titrated electrometncally with standard alkali to pH 8 2
Definitions
3 1 This method measures the mineral acidity of a sample plus the acidity resulting from
oxidation and hydrolysis of polyvalent cations, including salts of iron and aluminum
Interferences
4 1 Suspended matter present in the sample, or precipitates formed during the titration may
cause a sluggish electrode response This may be offset by allowing a 15-20 second pause
between additions of titrant or by slow drop wise addition of titrant as the endpomt pH is
approached
Apparatus
5 1 pH meter, suitable for electrometric titrations
Reagents
6 1 Hydrogen peroxide (H2O2, 30% solution)
6 2 Standard sodium hydroxide, 0 02 N
6 3 Standard sulfunc acid, 0 02 N
Procedure
7 1 Pipet 50 ml of the sample into a 250 ml beaker
7 2 Measure the pH of the sample If the pH is above 4 0, add standard sulfunc acid (6 3) in
5 0 ml increments to lower the pH to 4 0 or less If the initial pH of the sample is less than
4 0, the incremental addition of sulfunc acid is not required
7 3 Add 5 drops of hydrogen peroxide (61)
7 4 Heat the sample to boiling and continue boiling for 2 to 4 minutes In some instances, the
concentration of ferrous iron in a sample is such that an additional amount of hydrogen
peroxide and a slightly longer boiling time may be required
Approved for NPDES
Issued 1971
Technical revision 1974
305 1-1
-------
7 5 Cool the sample to room temperature and titrate electrometncally with standard sodium
hydroxide (6 2) to pH 8 2
8, Calculations
81 Acidity, as mg/1 CaCO, = [(A x B) - (C x D)] x 50,000
ml of sample
where
A = vol of standard sodium hydroxide used in titration
B == normality of standard sodium hydroxide
C = volume of standard sulfunc acid used to reduce pH to 4 or less
D = normality of standard sulfunc acid
82 If it is desired to report acidity in millequivalents per liter, the reported values as CaCO3
are divided by 50, as follows
Acidity as meq/1 = mg/1 CaCO3
9, Precision
91 On a round robin conducted by ASTM on 4 acid mine waters, including concentrations
up to 2000 mg/1, the precision was found to be ± 10 mg/1
Bibliography
1 Annual Book of ASTM Standards, Part 31, "Water", p 116, D 1067, Method E(1976)
2 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 277
Method 402(4d) (1975)
305 1-2
-------
United States
Environmental Protection
Agency
Environmental Monitoring and
Support Laboratory
Cincinnati OH 45268
Research and Development
vvEPA
Test Method
Acidity (Titrimetric)-
Method 305.2
1 Scope and Application
1 1 This method is applicable to
ram, surface and other waters of pH
less than 8 3
1 2 This method is a measure of the
concentration of strong and weak
acids that react with hydroxyl ions
This includes the dissolved gases that
are present
1 3 The range of this method
depends on the volume of sample
titrated and upon the precision that
the increments of titrant can be
measured If only 10 mL of sample is
available for analysis it is necessary
to use a 50 fiL syringe for dispensing
the titrant in order to achieve a
precision of less than 10 /ueq/L
2 Summary of Method
2 1 Samples are titrated with 0 02 N
carbonate free NaOH solution The
end point is determined with a pH
meter Results are reported as
microequivalents (/ueq) per liter
3 Sampling Handling and
Storage
3 1 The sample container must be
filled completely, sealed and stored at
4°C Care must be taken to minimize
exposure of the sample to the
atmosphere Open the sample
container immediately before analysis
3 2 Analysis should be performed as
soon as possible after collection
4 Comments
4 1 Samples with an initial pH
between 4 3 and 8 3 are subject to
error due to the loss or gam of
dissolved gases during sampling
storage and analyses
5 Apparatus
51 pH meter and electrode(s), see
Method 150 1 or 150 2
5 2 Micro buret or micro syrings
5 3 Teflon or glass magnetic stirring
bar
5 4 Magnetic stirrer
5 5 Beakers or flasks
6 Reagents
6 1 Standard sodium hydroxide
solution, 1 N Dissolve 40g NaOH in
250 mL distilled water Cool and dilute
to 1 liter with C02 free distilled water
Store in a polyolefin bottle and fitted
with a soda lime tube or tight cap to
protect from atmospheric C02
6 2 Standard sodium hydroxide
titrant, 0 02 N Dilute 20 0 mL of 1 N
NaOH with CO2-free distilled water to
1 liter Store in rubber stoppered
bottle Protect from atmospheric COa
by using a soda lime tube
Standardize against an 0 02 N
potassium acid phthalate solution
prepared by dissolving 4 085 g of
anhydrous KHCaH4O4 in COa free
distilled water and diluted to 1 1
7 Procedure
7 1 Pipet an appropriate aliquot of
sample into beaker of flask containing
a small teflon on glass stirring bar
Use extreme care to minimize the
sample surface disturbance
3052 1
Dec 1982
-------
7.2 Immerse pH electrode(s) into
sample and stir at a rate that does not
cause sample surface disturbance
7.3 Titrate with 0 02 N NaOH (6 2)
to pH 8 3 Titration should be made as
quickly as possible to prevent
absorption of atmospheric CO2
Record volume of titrant
8. Calculation
8 1 Acidity. //eq/L =TIx NB x 1 05
mLs
fjeq/L = microequivalents
per liter
mLa = mL of NaOH titrant
mLs = mL of sample
NB = normality of titrant
9. Precision and Accuracy
9 1 Precision and accuracy data are
not available
References
1 , Seymour, M D . Schubert, S A ,
Clayton, J W and Fernando, Q ,
Variation in the Acid Content of
Rain Water in the Course of a
Single Precipitation, Water, Air
and Soil Pollution 10{2) 147-161,
Aug 1978
2 Peden, M E and Skowron, Ionic
Stability of Precipitation Samples,
Atmospheric Environment, Vol
12, pp 2343-2349 1978
3 USGS, Methods for Collection and
Analysis of Water Samples for
Dissolved Minerals and Gases, p
39, (1970)
4 Annual Book of ASTM Standards,
part 31, "Water, ' p 107, D1067,
(1978)
5 Standard Methods for the
Examination of Water and
Wastewater, 14th Edition, p 273,
Met hod 402 (1975)
Dec 1982 3052-2
-------
ALKALINITY
Method 310.1 (Titrimetric, pH 4.5)
STORET NO. 00410
Scope and Application
1 1 This method is applicable to drinking, surface, and saline waters, domestic and industrial
wastes
1 2 The method is suitable for all concentration ranges of alkalinity, however, appropriate
aliquots should be used to avoid a titration volume greater than 50 ml
1 3 Automated titnmetric analysis is equivalent
Summary of Method
2 1 An unaltered sample is titrated to an electrometncally determined end point of pH 4 5
The sample must not be filtered, diluted, concentrated, or altered in any way
Comments
3 1 The sample should be refrigerated at 4°C and run as soon as practical Do not open
sample bottle before analysis
3 2 Substances, such as salts of weak organic and inorganic acids present in large amounts,
may cause interference in the electrometnc pH measurements
3 3 For samples having high concentrations of mineral acids, such as mine wastes and
associated receiving waters, titrate to an electrometnc endpomt of pH 3 9, using the
procedure in
Annual Book of ASTM Standards, Part 31, "Water", p 115, D-1067, Method D, (1976)
3 4 Oil and grease, by coating the pH electrode, may also interfere, causing sluggish
response
Apparatus
4 1 pH meter or electrically operated titrator that uses a glass electrode and can be read to
0 05 pH units Standardize and calibrate according to manufacturer's instructions If
automatic temperature compensation is not provided, make titration at 25 ±2° C
4 2 Use an appropriate sized vessel to keep the air space above the solution at a minimum
Use a rubber stopper fitted with holes for the glass electrode, reference electrode (or
combination electrode) and buret
4 3 Magnetic stirrer, pipets, flasks and other standard laboratory equipment
4 4 Burets, Pyrex 50,25 and 10 ml
Reagents
5 1 Sodium carbonate solution, approximately 0 05 N Place 25 ±0 2 g (to nearest mg)
Na2CO3 (dned at 250°C for 4 hours and cooled in desiccator) into a 1 liter volumetric
flask and dilute to the mark
Approved for NPDES
Issued 1971
Editorial revision 1978
310 1-1
-------
5.2 Standard acid (sulfunc or hydrochloric), 0 1 N Dilute 3 0 ml cone H2SO4 or 8 3 ml cone
HC1 to 1 liter with distilled water Standardize versus 40 0 ml of 0 05 N Na2CO3 solution
with about 60 ml distilled water by titrating potentiometncally to pH of about 5 Lift
electrode and rinse into beaker Boil solution gently for 3-5 minutes under a watch glass
cover Cool to room temperature Rinse cover glass into beaker Continue titration to the
pH inflection point Calculate normality using
N= A x B
5300 x C
• ' '
where
A = g Na2CO3 weighed into 1 liter
B = ml Na2CO3 solution
C t±= ml acid used to inflection point
,',-"' ' . ' '
5 3 Standard acid (sulfunc or hydrochloric), 0 02 N Dilute 200 0 ml of 0 1000 N standard
acid to 1 liter with distilled water Standardize by potentiometnc titration of 15 0 ml 0 05
N Na2CO3 solution as above
6 Procedure
6.1 Sample size ' '
6 1 1 Use a sufficiently large volume of titrant (> 20 ml in a 50 ml buret) to obtain good
precision while keeping volume low enough to permit sharp end point
6 1 2 For < 1000 mg CaCO3/l use 0 02 N titrant
6 1 3 For > 1000 mg CaCO3/l use 0 1 N titrant ,
6 1 4 A preliminary titration is helpful
6 2 Potentiometnc titration
6.2 1 Place sample in flask by pipetting with pipet tip near bottom of flask
622 Measure pH of sample
623 Add standard acid (5 2 or 5 3), being careful to stir thoroughly but gently to allow
needle to obtain equilibnum
624 Titrate to pH4 5. Record volume pf titrant
6 3 Potentiometnc titration of low alkalinity
63 1 For alkalinity of <20 mg/1 titrate 100-200 ml as above (62) using a 10 ml
microburet and 0 02 N acid solution (5 3)
632 Stop titration at pH in range of 4 3-4 7, record volume and exact pH Very
* carefully add titrant to lower pH exactly 0 3 pH units and record volume
7. Calculations
71 Potentiometnc titration to pH 4 5 - >
Alkalinity, mg/1 CaC03= A x N x 50,000
ml of sample
310 1-2
-------
where
A = ml standard acid
N = normality standard acid
7 2 Potentiometnc titration of low alkalinity
TotaUlkahmty.mg/iCaCO, = (2B
where
B = ml titrant to first recorded pH
C = total ml titrant to reach pH 0 3 units lower
N = normality of acid
Precision and Accuracy
8 1 Forty analysts in seventeen laboratories analyzed synthetic water samples containing
increments of bicarbonate, with the following results
Increment as
Alkalinity
mg/liter, CaCO3
8
9
113
119
Precision as
Standard Deviation
rag/liter, CaCO3
Accuracy as
Bias, Bias,
mg/1, CaCO3
127
1 14
528
536
+ 10.61
+22,29
- 8J9
- 7.42
+085
+ 20
-93
-88
(FWPCA Method Study 1, Mineral and Physical Analyses)
82 In a single laboratory (EMSL) using surface water samples at an average concentration
of 122 mg CaCO3/l, the standard deviation was ±3
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 278,
Method 403, (1975)
2 Annual Book of ASTM Standards, Part 31, "Watei", p 113, D-1067, Method B, (1976)
310 1-3
-------
ALKALINITY
Method 310.2 (Colorimetric, Automated, Methyl Orange)
STORET NO. 00410
1 Scope and Application
1 1 This automated method is applicable to drinking, surface, and saline waters, domestic
and industrial wastes The applicable range is 10 to 200 mg/1 as CaCO3
1 2 This method is not an approved NPDES method as cited in the Federal Register
December 1,1976 for samples containing tuibidity or color
2 Summary of Method
2 1 Methyl orange is used as the indicator in this method because its pH range is in the same
range as the equivalence point for total alkalinity, and it has a distinct color change that
can be easily measured The methyl orange is dissolved in a weak buffer at a pH of 3 1,
just below the equivalence point, so that any addition of alkalinity causes a loss of color
directly proportional to the amount of alkalinity
3 Sample Handling and Preservation
3 1 Sample should be refrigerated at 4°C and run as soon as practical Do not open sample
bottle before analysis
4 Interferences
4 1 Sample turbidity and color may interfere with this method Turbidity must be removed
by filtration prior to analysis If sample is filtered, this method is not approved for
NPDES monitoring Sample color that absorbs in the photometric range used will also
interfere
5 Apparatus
5 1 Techmcon AutoAnalyzer consisting of
5 1 1 Sampler I
5 1 2 Manifold
513 Proportioning pump
514 Colorimeter equipped with 15 mm tubular flow cell and 550 nm filters
515 Recorder equipped with range expander
6 Reagents
6 1 Methyl Orange Dissolve 0 125 g of methyl orange in 1 liter of distilled water
6 2 pH 3 1 Buffer Dissolve 5 1047 g of potassium acid phthalate in distilled water and add
87 6 ml 0 1 N HC1 and dilute to 1 liter Stable for one week
6 3 Methyl Orange-Buffered Indicator Add 1 liter of pH 3 1 buffer (6 2) to 200 ml methyl
orange solution (6 1) and mix well Stable for 24 hours
6 4 Stock Solution Dissolve 1 060 g of anhydrous sodium carbonate (oven-dried at 250°C for
4 hours) in distilled water and dilute to 1000 ml 1 0 ml = 1 00 mg CaCO3
Approved for NPDES
Issued 1971
Editorial revision 1974
3102-1
-------
641 Prepare a series of standards by diluting suitable volumes of stock solution to 100 0
ml with distilled water The following dilutions are suggested
ml of Stock
Solution Cone, mg/1 as CaCO3
10 10
20 20
40 40
60 60
80 80
100 100
180 180
200 200
7. Procedure
7 1 No advance sample preparation is required Set up manifold as shown in Figure 1
7 2 Allow both colorimeter and recorder to warm up for 30 minutes Run a baseline with all
reagents, feeding distilled water through the sample line Adjust dark current and
operative opening on colorimeter to obtain stable baseline
7 3 Place distilled water wash tubes in alternate openings on sampler and set sample timing
at 2 0 minutes
7 4 Place working standards in sampler in order of decreasing concentration Complete
filling of sampler tray with unknown samples
7 5 Switch sample line from distilled water to sampler and begin analysis
8. Calculation
8.1 Prepare standard curve by plotting peak heights of processed standards against known
concentrations Compute concentration of samples by comparing sample peak heights
with standard curve
9 Precision and Accuracy
91 In a single laboratory (EMSL), using surface water samples at concentrations of 15, 57,
154, and 193 mg/1 as CaCO3 the standard deviation was ±0 5
9.2 In a single laboratory (EMSL), using surface water samples at concentrations of 31 and
149 mg/1 as CaCO3 recoveries were 100% and 99%, respectively
Bibliography
1 Techmcon Auto Analyzer Methodology, Bulletin 1261, Techmcon Controls, Inc, Chauncey,
NY (1961)
2. Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 278,
Method 403 (1975)
3102-2
-------
310 2-3
-------
BROMIDE
Method 320.1 (Titrimetric)
STORET NO. 71870
Scope and Application
1 1 This method is applicable to drinking, surface, and saline waters, domestic and industrial
waste effluents
1 2 The concentration range for this method is 2-20 mg bromide/1
Summary of Method
2 1 After pretreatment to remove interferences, the sample is divided into two ahquots One
aliquot is analyzed for iodide by converting the iodide to lodate with bromine water and
titrating lodometncally with phenylarsine oxide (PAO) or sodium thiosulfate The other
aliquot is analyzed for iodide plus bromide by converting these hahdes to lodate and
bromate with calcium hypochlonte and titrating lodometncally with PAO or sodium
thiosulfate Bromide is then calculated by difference
Sample Handling and Preservation
3 1 Store at 4°C and analyze as soon as possible
Interferences
4 1 Iron, manganese and organic matter can interfere, however, the calcium oxide
pretreatment removes or reduces these to insignificant concentrations
4 2 Color interferes with the observation of indicator and bromine-water color changes This
interference is eliminated by the use of a pH meter instead of a pH indicator and the use
of standardized amounts of oxidant and oxidant-quencher
Reagents
5 1 Acetic Acid Solution (1 8) Mix 100 ml of glacial acetic acid with 800 ml of distilled
water
5 2 Bromine Water In a fume hood, add 0 2 ml bromine to 500 ml distilled water Stir with a
magnetic sttrrer and a Teflon-coated stirring bar for several hours or until the bromine
dissolves Store in a glass-stoppered, colored bottle
5 3 Calcium Carbonate (CaCO3) Powdered
5 4 Calcium Hypochlonte Solution (Ca(OCl)2), Add 35 g of Ca(OCl)2 to approximately 800
ml of distilled water m a 1 liter volumetric flask Stir on a magnetic stirrer for
approximately 30 minutes Dilute to 1 liter and filter Store in a glass-stoppered, colored
flask
5 5 Calcium Oxide (CaO) Anhydrous, powdered
5 6 Hydrochloric Acid Solution (1 4) Mix 100 ml of HC1 (sp gr 1 19) with 400 ml of
distilled water
Approved for NPDES
Issued 1974
320 1-1
-------
5 7 Potassium Iodide (KI) Crystals, ACS Reagent Grade
5 8 Sodium Acetate Solution (275 g/1) Dissolve 275 g sodium acetate tnhydrate
(NaC2H3O2«3H2O) in distilled water Dilute to 1 liter and filter
5 9 Sodium Chloride (NaCl) Crystals, ACS Reagent Grade
5.10 Sodium Formate Solution (500 g/1) Dissolve 50 g sodium formate (NaCHO2) in hot
distilled water and dilute to 100 ml
5 11 Sodium Molybdate Solution (10 g/1) Dissolve 1 g sodium molybdate (Na2MoO4«2H2O)
in distilled water and dilute to 100 ml
5 12 Sulfunc Acid Solution (1 4) Slowly add 200 ml H2SO4 (sp gr 1 84) to 800 ml of distilled
water
513 Phenylarsme Oxide (0 0375N) Hach Chemical Co, or equivalent Standardize with
0 0375 N potassium buodate (5 19, 5 23)
5 14 Phenylarsme Oxide Working Standard (0 0075 N) Transfer 100 ml of commercially
available 0 0375 N phenylarsme oxide (5 13) to a 500 ml volumetric flask and dilute to
the mark with distilled water This solution should be prepared fresh daily
5 15 Commercially available starch indicator such as thyodene or equivalent may be used
5 16 Sodium Thiosulfate, Stock Solution, (0 75 N) Dissolve 186 14 g Na2S2O3»5H2O in boiled
and cooled distilled water and dilute to 1 liter Preserve by adding 5 ml chloroform
5 17 Sodium Thiosulfate Standard Titrant, (0 0375 N) Prepare by diluting 50 0 ml of stock
solution (5 16) to 10 liter Preserve by adding 5 ml of chloroform Standardize with
0 0375 N potassium buodate (5 19, 5 23)
5.18 Sodium Thiosulfate Working Standard (00075 N) Transfer 100 ml of sodium
thiosulfate standard titrant (5 17) to a 500 ml volumetric flask and dilute to the mark
with distilled water This solution should be prepared fresh daily
5 19 Potassium Bnodate Standard, (0 0375 N) Dissolve 4 873 g potassium buodate,
previously dried 2 hours at 103°C, in distilled water and dilute to 1 0 liter Dilute 250 ml
to 1 0 liter for 0 0375 N buodate solution
5 20 Starch Solution Prepare an emulsion of 10 g of soluble starch in a mortar or beaker with
a small quantity of distilled water Pour this emulsion into 1 liter of boiling water, allow
to boil a few minutes, and let settle overnight Use the clear supernate This solution may
be preserved by the addition of 5 ml per liter of chloroform and storage in a 10°C
refrigerator Commercially available dry, powdered starch indicators may be used in
place of starch solution
521 Nitrogen Gas Cylinder
5 22 Potassium Fluoride (KF»2H2O) ACS Reagent Grade
5 23 Standardization of 0 0375 N Phenylarsme Oxide and 0 0375 N Sodium Thiosulfate
Dissolve approximately 2 g ( ± 1 0 g) KI (5 7) in 100 to 150 ml distilled water, add 10 ml
H2SO4 solution (5 12) followed by 20 ml standard potassium buodate solution (5 19)
Place in dark for 5 minutes, dilute to 300 ml and titrate with the phenylarsme oxide
(5 13) or sodium thiosulfate (5 17) to a pale straw color Add a small scoop of indicator
(5 15) Wait until homogeneous blue color develops and continue the titration drop by
drop until the color disappears Run in duplicate Duplicate determinations should agree
within ±005 ml
320 1-2
-------
Procedure
6 1 Pretreatment
611 Add a visible excess of CaO (5 5) to 400 ml of sample Stir or shake vigorously for
approximately 5 minutes Filter through a dry, moderately retentive filter paper,
discarding the first 75 ml
6 2 Iodine Determination
621 Place 100 ml of pretreated sample (6 1) or a fraction thereof diluted to that volume,
into a 150 ml beaker Add a Teflon-coated stirring bar and place on a magnetic
stirrer Insert a pH electrode and adjust the pH to approximately 7 or slightly less
by the dropwise addition of H2SO4 solution (5 12)
622 Transfer the sample to a 250 ml widemouthed conical flask Wash beaker with
small amounts of distilled water and add washings to the flask A 250 ml iodine
flask would increase accuracy and precision by preventing possible loss of the
iodine generated upon addition of potassium iodide and sulfunc acid (641)
623 Add 15 ml sodium acetate solution (5 8) and 5 ml acetic acid solution (5 1) Mix
well Add 40 ml bromine water solution (5 2), mix well Wait 5 minutes
624 Add 2 ml sodium formate solution (5 10), mix well Wait 5 minutes
625 Purge space above sample with gentle stream of nitrogen (521) for approximately
30 seconds to remove bromine fumes
626 If a precipitate forms (iron), add 0 5 g KF«2H2O (5 22)
6 2 7 A distilled water blank must be run with each set of samples because of iodide in
reagents If the blank is consistently shown to be zero for a particular "lot" of
chemicals, it can be ignored
628 Titrate as described in 6 4
6 3 Bromide Plus Iodide Determination
631 Place 100 ml of pretreated sample (6 1) or a fraction thereof diluted to that volume,
in a 150 ml beaker Add 5 g NaCl and stir to dissolve Neutralize by dropwise
addition of HC1 solution (5 6) as in (6 2 1) Transfer as in (6 2 2)
632 Add 20 ml of calcium hypochlonte solution (5 4) Add 1 ml of HC1 solution (5 6)
and add approximately 0 2 g calcium carbonate (5 3)
633 Heat to boiling on a hot plate, maintain boiling for 8 minutes
634 Remove from hot plate and carefully add 4 ml sodium formate solution (5 10)
Caution TOO RAPID ADDITION MAY CAUSE FOAMING Wash down
sides with distilled water
635 Return to hot plate and maintain boiling conditions for an additional 8 minutes
Occasionally wash down sides with distilled water if residue is deposited from
boiling action
636 Remove from hot plate Wash down sides and allow to cool
6 3 7 If a precipitate forms (iron), add 0 5 g KF«2H2O (5 22)
638 Add 3 drops sodium molybdate solution (5 11)
6 3 9 A distilled water blank must be run with each set of samples because of iodide,
lodate, bromide, and/or bromate in reagents
6310 Titrate as described in 6 4
320 1-3
-------
6 4 Titration
6 4 1 Dissolve approximately 1 g potassium iodide (5 7) in sample from (6 2 8 or 6 3 10)
Add 10 ml of fr2SO4 solution (5 12) and place in dark for 5 minutes
642 Titrate with standardized phenylarsine pxide working standard (5 14) or sodium
thiosulfate working standard (5 18), adding indicator (5 15 or 5 20) a&end point is
approached (light straw color) Titrate to colorless solution Disregard returning
blue color
7 Calculations
7 1 Principle Iodide is determined by the titration of the sample as oxidized in (6 2)
bromide plus iodide is determined by the titration of the sample as oxidized in (6 3) The
amount of bromide is then determined by difference The number of equivalents of iodine
produced a constant of 13,320 as shown in the equation in (7 2) Experimental data is
entered in the appropriate place and the equation is solved for mg/1 bromide
7 2 Equation
Br(mg/l) = 13,320
where
A = the number of ml of PAO needed to titrate the sample for bromide plus iodide
(with the number of ml of PAO needed to titrate the blank subtracted)
B = the normality of the PAO needed to titrate the sample for bromide plus
iodide
C = the volume of sample taken (100 ml or a fraction thereof) to be titrated for
bromide plus iodide
D = the number of ml of PAO needed to titrate the sample for iodide (with the
number of ml of PAO needed to titrate the blank subtracted) The blank for
the iodide titration is often zero
E = the normality of the PAO used to titrate the sample for iodide
F = the volume of sample taken (100 ml or a fraction thereof) to be titrated for
iodide
8. Precision and Accuracy
81 In a single laboratory (EMSL), using a mixed domestic and industrial waste effluent, at
concentrations of 0 3, 2 8, 5 3, 10 3 and 20 3 mg/1 of bromide, the standard deviations
were ±013, ±037, ±038, ±044 and ±042mg/l,"respectively
82 In a single laboratory (EMSL), using a mixed domestic and industrial waste effluent, at
concentrations of 2 8, 5 3, 10 3 and 20 3 mg/1 of bromide, recoveries were 96, 83, 97 and
99%, respectively
320 1-4
-------
Bibliography
1 Annual Book of ASTM Standards, Part 31, "Water", Standard D1246-68, Method C, p 328
(1976)
2 Bender, D F , "Modification of the lodimetnc Titration Methods for the Determination of
Bromide and its application to Mixed Domestic-Industrial Waste Effluents", Analyst
(London), 100. p 400-404 (June 1975)
320 1-5
-------
CHLORIDE
Method 325.1 (Colorimetric, Automated Ferricyanide AAI)
STORET NO. 00940
Scope and Application
1 1 This automated method is applicable to drinking, surface, and saline waters, domestic
and industrial wastes The applicable range is 1 to 250 mg Cl/1 Approximately 15
samples per hour can be analyzed
Summary of Method
2 1 Thiocyanate ion (SCN) is liberated from mercuric thiocyanate'through sequestration of
mercury by chloride ion to form un-iomzed mercuric chloride In the presence of ferric
ion, the liberated SCN forms highly colored ferric thiocyanate in concentration
proportional to the original chloride concentration
Sample Handling and Preservation
3 1 No special requirements
Interferences
4 1 No significant interferences
Apparatus
5 1 Techmcon Auto Analyzer consisting of
5 1 1 Sampler I
512 Continuous filter
5 1 3 Manifold
514 Proportioning pump
5 1 5 Colorimeter equipped with 15 mm tubular flow cell and 480 nm filters
516 Recorder
Reagents
6 1 Ferric Ammonium Sulfate Dissolve 60 g of FeNH4(SO4)2«12H2O in approximately 500
ml distilled water Add 355 ml of cone HNO3 and dilute to 1 liter with distilled water
Filter
6 2 Saturated Mercunc Thiocyanate Dissolve 5 g of Hg(SCN)2 in 1 liter of distilled water
Decant and filter a portion of the saturated supernatant liquid to use as the reagent and
refill the bottle with distilled water
6 3 Stock Solution (0 0141 N NaCl) Dissolve 0 8241 g of pre-dried (140°C) NaCl in distilled
water Dilute to 1 liter in a volumetric flask 1 nil = 0 5 mg Cl
631 Prepare a series of standards by diluting suitable volumes of stock solution to 100 0
ml with distilled water The following dilutions are suggested
Approved for NPDES
Issued 1971
325 1-1
-------
ml of Stock
Solution Cone, mg/1
10 50
20 100
40 200
80 400
15 0 75 0
20 0 100 0
30 0 150 0
40 0 200 0
50 0 250 0
7 Procedure
7.1 No advance sample preparation is required Set up manifold as shown in Figure 1 For
water samples known to be consistently low in chloride content, it is advisable to use only
one distilled water intake line
7 2 Allow both colorimeter and recorder to warm up for 30 minutes Run a baseline with all
reagents, feeding distilled water through the sample line Adjust dark current and
operative opening on colorimeter to obtain stable baseline
7 3 Place distilled water wash tubes in alternate openings in sampler and set sample timing at
2 0 minutes
7 4 Place working standards in sampler in order of decreasing concentrations Complete
filling of sampler tray with unknown samples
7 5 Switch sample line from distilled water to sampler and begin analysis
8 Calculation
8 1 Prepare standard curve by plotting peak heights of processed standards against known
concentrations Compute concentration of samples by comparing sample peak heights
with standard curve
9 Precision and Accuracy
91 In a single laboratory (EMSL), using surface water samples at concentrations of 1, 100,
and 250 mg Cl/1, the standard deviation was ±0 3
92 In a single laboratory (EMSL), using surface water samples at concentrations of 10 and
100 mg Cl/1, recoveries were 97% and 104%, respectively
Bibliography
1 J E O'Brien, "Automatic Analysis of Chlorides m Sewage", Waste Engr , 33, 670-672 (Dec
1962)
2 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 613,
Method 602 (1975)
325 1-2
-------
325 1-3
-------
CHLORIDE
Method 325.2 (Colorimetric, Automated Ferricyanide AAII)
STORET NO. 00940
Scope and Application
1 1 This automated method is applicable to drinking, surface, and saline waters, domestic
and mdustral wastes The applicable range is 1 to 200 mg Cl/1 This range may be
extended by sample dilution Approximately 30 samples per hour can be analyzed
Summary of Method
2 1 Thiocyanate ion (SCN) is liberated from mercuric thiocyanate through sequestration of
mercury by chloride ion to form un-ionized mercuric chloride In the presence of feme
ion, the liberated SCN forms highly colored feme thiocyanate in concentration
proportional to the original chloride concentration
Sample Handling and Preservation
3 1 No special requirements
Interferences
4 1 No significant interferences
Apparatus
5 1 Techmcon AutoAnalyzer consisting of
511 Sampler
512 Continuous filter (optional)
513 Analytical cartridge
514 Proportioning pump
5 1 5 Colorimeter equipped with 15 mm tubular flow cell and 480 nm filters
516 Recorder
5 1 7 Digital printer (optional)
Reagents
6 1 Mercuric thiocyanate solution Dissolve 4 17 gm of Hg(SCN)2 in 500 ml of methanol
Dilute to 1 liter with methanol, mix and filter through filter paper
6 2 Ferric nitrate solution, 20 2% Dissolve 202 gm of Fe(NO3)3»9 H2O in 500 ml of distilled
water Add 31 5 ml cone nitric acid, mix and dilute to 1 liter with distilled water
6 3 Color reagent Add 150 ml of mercuric thiocyanate solution (6 1) to 150 ml of feme
nitrate solution (6 2), mix, and dilute to 1 liter with distilled water
6 4 Stock Solution (0 0141 N NaCl) Dissolve 0 8241 g of pre-dried (140°C) NaCl in distilled
water Dilute to 1 liter in a volumetric flask 1 ml = 0 5 mg Cl
641 Prepare a series of standards by diluting suitable volumes of stock solution to 100 0
ml with distilled water The following dilutions are suggested
Approved for NPDES
Issued 1978
325 2-1
-------
ml of Stock Cone, mg/1
Solution
10 50
20 100
40 200
80 400
150 750
20 0 100 0
300 1500
400 2000
7 Procedure
7 1 Where participate matter is present, the sample must be filtered prior to the
determination This can be accomplished by having the Techmcon continuous filter as an
integral part of the system The sample may be centnfuged in place of filtration
7 2 Allow both colorimeter and recorder to warm up for 30 minutes Run a baseline with all
reagents, feeding distilled water through the sample line
7.3 Place working standards in sampler in order of decreasing concentrations Complete
filling of sampler tray with unknown samples
7,4 When a stable baseline has been obtained, start the sampler
8 Calculation
8 1 Prepare standard curve by plotting peak heights of processed standards against known
concentrations Compute concentration of samples by comparing sample peak heights
with standard curve
9. Precision and Accuracy
9 1 Precision and accuracy data are not available at this time
Bibliography
1. J E, O'Brien, "Automatic Analysis of Chlorides in Sewage", Waste Engr, 33, 670-672 (Dec
1962)
2. Techmcon AutoAnalyzer II, Industrial Method No 99-70W, Techmcon Industrial Systems,
Tarrytown, N Y, 10591 (Sept 1973)
325 2-2
-------
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325 2-3
-------
CHLORIDE
Method 325.3 (Titrimetric, Mercuric Nitrate)
STORET NO. 00940
1 Scope and Application
1 1 This method is applicable to drinking, surface, and saline waters, domestic and industrial
wastes
1 2 The method is suitable for all concentration ranges of chloride content, however, m order
to avoid large titration volume, a sample aliquot containing not more than 10 to 20 mg Cl
per 50 ml is used
1 3 Automated titration may be used
2 Summary of Method
2 1 An acidified sample is titrated with mercuric nitrate m the presence of mixed
diphenylcarbazone-bromophenol blue indicator The end point of the titration is the
formation of the blue-violet mercury diphenylcarbazone complex
3 Comments
3 1 Amons and cations at concentrations normally found m surface waters do not interfere
3 2 Sulfite interference can be eliminated by oxidizing the 50 ml of sample solution with 0 5
tolmlofH2O2
4 Apparatus
4 1 Standard laboratory titnmetnc equipment including a 1 ml or 5 ml microburet with 001
ml graduations
5 Reagents
5 1 Standard sodium chloride, 0 025 N Dissolve! 4613 g±0 0002 g sodium chloride (dried
at 600 °C for 1 hour) in chloride-free water m a 1 liter volumetric flask and dilute to the
mark 1 ml = 886 5 fjg Cl
5 2 Nitric acid, HNO3 solution (3 + 997)
5 3 Sodium hydroxide solution, NaOH, (10 g/1)
5 4 Hydrogen peroxide (30%), H2O2
5 5 Hydroqumone solution (10 g/hter) Dissolve 1 g of purified hydroqumone m water m a
100 ml volumetric and dilute to the mark
5 6 Mercuric nitrate titrant (0 141 N) Dissolve 25 g Hg(NO3)2«H2O m 900 ml of distilled
water acidified with 5 0 ml cone HNO3 m a 1 liter volumetric flask and dilute to the
mark with distilled water Filter if necessary Standardize against standard sodium
chloride solution (5 1) using procedure 6 Adjust to exactly 0 141 N and check Store in a
dark bottle A 1 00 ml aliquot is equivalent to 5 00 mg of chloride
5 7 Mercuric nitrate titrant (0 025 N) Dissolve 4 2830 g Hg(NO3)2»H2O m 50 ml of distilled
water acidified with 0 5 ml cone HNO3 (sp gr 1 42) m a 1 liter volumetric flask and
dilute to the mark with distilled water Filter if necessary Standardize against standard
Approved for NPDES
Issued 1971
Editorial revision 1978 and 1982
325 3-1
-------
sodmm chloride solution (5 1) using procedure 6 Adjust to exactly 0 025 N and check
Store m a dark bottle
5 8 Mercuric nitrate titrant (0 0141 N) Dissolve 2 4200 g Hg(NO3)2«H2O m 25 ml of
distilled water acidified with 0 25 ml of cone HNO3 (sp gr 1 42) m a 1 liter volumetric
flask and dilute to the mark with distilled water Filter if necessary Standardize against
standard sodium chloride solution (5 1) using procedure 6 Adjust to exactly 0 0141 N
and check Store m a dark bottle A 1 ml aliquot is equivalent to 500 ug of chloride
5 9 Mixed indicator reagent Dissolve 0 5 g crystalline diphenylcarbazone and 0 05 g
bromophenol blue powder m 75 ml 95% ethanol in a 100 m' volumetric flask and dilute
to the mark with 95% ethanol Store m brown bottle and discard after 6 months
5 10 XylenecyanoleFF solution Dissolve 0 005 g of xylene cyanole FF dye in 95% ethanol or
isopropanol in a 100 ml volumetric and dilute to the mark with 95% ethanol or
isopropanol
6. Procedure
6.1 Use 50 ml of sample or an aliquot of sample diluted to 50 ml with distilled water, so that
the concentration of chloride does not exceed 20 mg/ahquot If the sample or aliquot
contains more than 2 5 mg of chloride, use 0 025N mercuric nitrate titrant (5 7) in step
6.6 If the sample or aliquot contains less than 2 5 mg of chloride, use 0 0141N mercuric
nitrate titrant (5 8) in step 6 6 Determine an indicator blank on 50 ml chloride-free
water using step 6 6 If the sample contains less than 0 1 mg/1 of chloride concentrate an
appropriate volume to 50 ml
6 2 Add 5 drops of mixed indicator reagent (5 9), shake or swirl solution
6.3 If a blue-violet or red color appears add HNO3 solution (5 2) dropwise until the color
changes to yellow
64 If a yellow or orange color forms immediately on addition of the mixed indicator, add
NaOH solution (5,3) dropwise until the color changes to blue-violet, then add HNO3
solution (5 2) dropwise until the color changes to yellow
6 5 Add 1 ml excess HNO3 solution (5 2)
6 6 Titrate with 0 025 N mercuric nitrate titrant (5 7) until a blue-violet color persists
throughout the solution See 6 1 for choice of titrant normality (Xyjene cyanollFF
solution (5 10) may be added with the indicator to sharpen the end point This will
change color shades Practice runs should be made
6.7 Additional steps to eliminate particular interferences
6 7 1 If chromate is present and iron is not present the end point may be difficult to
detect
be an olive-purple color
6 7 2 If chromate is present at > 100 mg/1 and iron is not present, add 2 ml of fresh
hydroqumone solution (5 5)
673 If ferric ion is present use volume containing no more than 2 5 mg of ferric ion or
ferric ion plus chromate ion Add 2 ml fresh hydroqumone solution (5 5)
674 If sulfite ion is present, add 0 5 ml of H2O2 solution (5 4) to 50 ml sample and mix
for 1 minute
325 3-2
-------
Calculation
= (A
where
A = ml titrant for sample
B = ml titrant for blank
N = normality mercuric nitrate titrant
mg NaCl/1 = mg chloride/1 x 1 65
Precision and Accuracy
8 1 Forty two analysts in eighteen laboratories analyzed synthetic water samples containing
exact increments of chloride, with the following results
Increment as
Chloride
mg/hter
Precision as
Standard Deviation
mg/hter
Bias,
%
Accuracy as
Bias,
mg/hter
17
18
91
97
382
398
154
132
292
316
1170
1180
+ 2 16
+ 350
+011
-051
-061
-1 19
+04
+06
+01
-05
-23
-47
(FWPCA Method Study 1, Mineral and Physical Analyses)
8,2 In a single laboratory (EMSL), using surface water samples at an average concentration
of 34 mg Cl/1, the standard deviation was ±10
83 A synthetic unknown sample containing 241 mg/1 chloride, 108 mg/1 Ca, 82 mg/1 Mg,
3 1 mg/1 K, 19 9 mg/1 Na, 1 1 mg/1 nitrate N, 0 25 mg/1 nitrite N, 259 mg/1 sulfate
and 42 5 mg/1 total alkalinity (contributed by NaHCO3) in distilled water was analyzed
in 10 laboratories by the mercunmetnc method, with a relative standard deviation of
33% and a relative error of 2 9%
Bibliography
1 Annual Book of ASTM Standards, Part 31, "Water", Standard D512-67, Method A, p 270
(1976)
325 3-3
-------
CHLORINE, TOTAL RESIDUAL
Method 330.1 (Titrimetric, Amperometric)
STORET NO. 50060
1 Scope and Application
1 1 The amperometnc titration method is applicable to all types of waters and wastes that do
not contain a substantial amount of organic matter
2 Summary of Method
2 1 Chlorine (hypochlonte ion, hypochlorous acid) and chlorammes stoichiometncally
liberate iodine from potassium iodide at pH 4 or less
2 2 The iodine is titrated with standard reducing agent such as sodium thiosulfate or
phenylarsine oxide using an amperometer to determine the end point
2 3 The results are calculated as mg/1 Cl even though the actual measurement is of total
oxidizing power because chlorine is the dominant oxidizing agent present
3 Interferences
3 1 Manganese, nitrite and iron do not interfere
3 2 Stirring can lower chlonne values by volatilization
33 If dilution is necessary, it must be done with distilled water which is free of chlonne,
chlorine-demand and ammonia
3 4 Copper and silver poison the electrode
4 Apparatus
4 1 An amperometer consisting of a microammeter with necessary electrical accessories, a
cell unit with a salt bridge, reference electrode and an agitator Commercially available
If the entire system (including titrant delivery system) is to be used, make sure that the
volume read off the pipet or buret is really being delivered to the sample cell Reservoir-
type system sometimes back up, producing false readings
42 A microburet, 0-2 ml or 0-10 ml, depending on required precision, accuracy and range
5 Reagents
5 1 Phenylarsine oxide solution (0 00564N), commercially available, Wallace and Tiernan or
equivalent Standardize with potassium bnodate (5 8, 5 9)
5 2 Potassium Iodide, KI, crystals
5 3 Potassium Iodide Solution Dissolve 50 g KI in freshly boiled and cooled distilled water
and dilute to 1 liter Store in colored, glass-stoppered bottle in refrigerator Discard when
yellow color develops
5 4 Commercially available starch indicators such as thyodene or equivalent may be used
5 5 Acetate buffer solution (pH 4) Dissolve 146g anhydrous NaC2H3O2 or 243g
NaC2H3O2»3H2O in 400 ml distilled water, add 480g cone acetic acid and dilute to 1 liter
with distilled water
Approved for NPDES
Issued 1974
Editorial revision 1978
330 1-1
-------
5 6 Sulfunc Acid (1 4) Slowly add 200 ml H2SO4 (sp gr 1 84) to 800 ml of distilled water
5 7 Potassium buodate (0 IN) Dissolve 3 249g potassium buodate, previously dried 2 hours
at 103°C, in distilled water and dilute to 1 0 liters Store in a glass stoppered bottle
5 8 Potassium buodate (0 005N) Dilute 50 ml of 0 IN potassium buodate (5 7) to 1-hter in a
volumetric flask Store in a glass stoppered bottle
5 9 Standardization of 000564N phenylarsine oxide Dissolve approximately 2g (±lg) KI
(5 2) in 100 to 150 ml distilled water, add 10 ml H2SO4 solution (5 6) followed by 20 ml
0 005N potassium buodate solution (5 8) Place in dark for 5 minutes, dilute to 300 ml
and titrate with 0 00564N phenylarsine oxide solution (5 1) to a pale straw color Add a
small scoop of indicator (5 4) Wait until homogeneous blue color develops and continue
the titration drop by drop until the color disappears Run in duplicate Duplicate
determinations should agree within ±0 05 ml
NPAO= 20 x ° °°5
ml PAO
Adjust PAO solution if necessary and recheck
Procedure
6 1 Place 200 ml of sample in the sample container This volume is convenient because the
buret reading m millihters is equivalent to mg/1 Cl Up to 2 mg/1 is reliably titrated this
way Smaller sample ahquots diluted to 200 ml are used for concentrations greater than 2
mg/1 The construction of the cell and electrode component usually require 200 ml of
sample
6 2 Place on electrode assembly
6 3 Add 1 0 ml KI solution (5 3)
6 4 Add 1 ml acetate buffer (5 5)
6 5 Titrate with 0 00564N PAO (5 1)
66 As each increment is added the needle deflects toward rest When the needle no longer
deflects subtract the last drop added from the buret reading to obtain the mg/1 Cl Less
and/or slower deflection signals that the end point is near
Calculations
7.1 For 0 00564N PAO and a 200 ml sample there are no calculations The buret reading is
in mg/1 The last increment, when the needle does not deflect toward rest, must be
subtracted
Precision and Accuracy
8 1 More than 20 laboratories analyzed prepared samples of 0 64 and 1 "83 mg/1 total Cl
The relative standard deviations were 24 8% and 12 5% respectively and the relative
errors were 85% and 88% respectively
330 1-2
-------
In a single operator, single laboratory situation the following results were obtained
Rel Stand Dev
Sample
Matrix
Distilled Water
Drinking Water
River Water
Domestic Sewage
Average
mg/1
038
350
097
057
041
Stand Dev
mg/1
002
001
003
002
003
61
02
26
30
69
For these samples the results were compared to the lodometnc titration as a means of obtaining a relative
accuracy
lodometnc Amperometnc
% Recovery
1032
1018
820
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 322,
Method 409C (1975)
2 Annual Book of ASTM Standards, Part 31, "Water", Standard D 1253-76, p 277, Method A
(1976)
3 Bender, D F , "Comparison of Methods for the Determination of Total Available Residual
Chlorine in Various Sample Matrices", EPA Report-600/4-78-019
Sample
Matrix
Drinking Water
River Water
Domestic Sewage
lodometnc
Titration mg/1
094
056
050
Amperometnc
Titration mg/1
097
057
041
330 1-3
-------
CHLORINE, TOTAL RESIDUAL
Method 330.2 (Titrimetric, Back, lodometric)
(Starch or Amperometric Endpoint)
STORET NO. 50060
Scope and Application
1 1 The lodometric backtitration method is applicable to all types of waters but is primarily
used for wastewater because it eliminates any contact between the full concentration of
liberated iodine and the wastewater
Summary of Method
2 1 Chlorine (hypochlonte ion, hypochlorous acid) and chlorammes stoichiometncally
liberate iodine from potassium iodide at pH 4 or less
2 2 The iodine immediately quantitatively oxidizes a standardized reducing agent such as
sodium thiosulfate or phenylarsine oxide
2 3 The excess reducing agent is then determined by titrating with a standard iodine titrant
The starch endpomt color change is from clear to blue
24 A subtraction of the excess amount of reducing agent is included in the calculations and
the results are reported as mg/1 Cl even though the actual measurement is of total
oxidizing power because chlorine is the dominant oxidizing agent present
Interferences
3 1 Manganese, iron and nitrite interference may be minimized by buffering to pH 4 before
the addition of KI
3 2 High concentrations of organics may cause uncertainty in the endpomt This uncertainty
can be reduced by acidifying to pH 1 0 if manganese, iron and nitrite are absent
3 3 Turbidity and color may make the endpomt difficult to detect Practice runs with spiked
samples may be necessary
Apparatus
4 1 Standard laboratory glassware is used A microburet 0-2 ml or 0-10 ml is used
depending on the desired range and accuracy
Reagents
5 1 Phenylarsine oxide solution (0 00564N) Wallace and Tierman or equivalent
Standardize with potassium buodate (5 6, 5 9)
5 2 Acetate buffer solution (pH 4) Dissolve 146 g anhydrous NaC2H3O2 or 243 g
NaC2H3O2«3H2O in 400 ml distilled water, add 480 g cone acetic acid and dilute to 1 liter
with distilled water
5 3 Standard iodine solution (0 IN) Dissolve 40 g KI in 25 ml distilled water, add 13 g
resublimed iodine and stir until dissolved Transfer to a 1 liter volumetric flask and dilute
to the mark Determine the exact normality (5 11)
Approved for NPDES
Issued 1978
330 2-1
-------
5 4 Standard iodine titrant (0 0282N) Dissolve 25 g KI m a little distilled water in a 1 liter
volumetric flask Add the calculated amount of 0 IN standard iodine (5 3) to produce a
0.0282N solution Standardize daily (5 12) Store m amber bottle or in dark, protect from
sunlight at all tunes and keep from contact with rubber
5.5 Potassium biiodate (0 IN) Dissove 3 249g potassium buodate, previously dried 2 hours
at 103"C, in distilled water and dilute to 1 0 liter Store in a glass stoppered bottle
5.6 Potassium biiodate (0 005N) Dilute 50 ml of 0 IN potassium buodate (5 5) to 1 liter in a
volumetric flask Store m glass stoppered bottle
5 7 Commercially available starch indicators such as thyodene or equivalent may be used
5.8 Sulfunc Acid Solution (1 4) Slowly add 200 ml H2SO4 (sp gr 1 84) to 800 ml of distilled
water
5 9 Standardization of 0 00564N phenylarsme oxide Dissolve approximately 2g (± Ig) KI in
100 to 150 ml distilled water, add 10 ml H2SO4 solution (5 8) followed by 20 ml 0 005N
potassium buodate solution (5 6) Place in dark for 5 minutes, dilute to 300 ml and titrate
with 0 00564N phenylarsme oxide solution (5 1) to a pale straw color Add a small scoop
of indicator (5 7) Wait until homogenous blue color develops and continue the titration
drop by drop until the color disappears Run m duplicate Duplicate determinations
should agree within ±005 ml
NPAO =20X0005
mlPAO
Adjust PAO solution if necessary and recheck
5 10 Standardization of 0 0375N phenylarsme oxide Dissolve approximately 2 g (± Ig) KI in
100 to 150 ml distilled water, add 10 ml H2SO4 solution (5 8) followed by 20 ml 0 IN
potassium buodate solution (5 5) Place in dark for 5 minutes, dilute to 300 ml and titrate
with 0 0375N phenylarsme oxide solution (5 10) to a pale straw color Add a small scoop
of indicator (5 7) Wait until homogenous blue color develops and continue the titration,
drop by drop until the color disappears Run in duplicate Duplicate determination
should agree within ±0 05 ml
NPAO = 20X01
ml PAO
Adjust PAO solution if necessary and recheck
511 Standardization of 0 IN Iodine solution Dissolve approximately 2g (± 1 g) KI in 100 to
150 ml distilled water, add 20 ml Iodine Solution (5 3) Dilute to 300 ml and titrate with
0 0375N phenylarsme oxide solution (5 10) to a pale straw color Add a small scoop of
indicator (5 7) Wait until homogenous blue color develops and continue the titration
330 2-2
-------
drop by drop until the color disappears Run in duplicate Duplicate determinations
should agree within ±0 05 ml
NT ml PAQ X 0 0375
N'a = 20
Adjust iodine solution if necessary and recheck
512 Standardization of 0 0282N Iodine solution Dissolve approximately 2 g (± 1 g) KI in 100
to 150 ml distilled water, add 20 ml Iodine solution (5 4) Dilute to 300 ml and titrate
with 0 0375N phenylarsine oxide solution (5 10) to a pale straw color Add a small scoop
of indicator (5 7) Wait until homogenous blue color develops and continue the titration
drop by drop until the color disappears Run in duplicate Duplicate determinations
should agree within ±0 05 ml
XT ml PAO X 0 0375
N'*= 20
Adjust iodine solution if necessary and recheck
Procedure
6 1 Starch-Iodide End Point
6 1 1 Place 5 00 ml of 0 00564N PAO solution (5 9) in a flask
612 Add approximately Ig KI on a scoop
6 1 3 Add 4 ml acetate buffer solution (5 2)
614 Add 200 ml of sample For concentrations above 10 mg/1, a sample of less volume
may be diluted to 200 ml wth chlorine-free, chlorine demand-free distilled water
61 5 Mix well
616 Add approximately 4 mg indicator (5 7) just before titration
617 Titrate with 0 0282N iodine solution (5 12) to the first appearance of a blue color
that persists after mixing Record the ml of titrant used
6 2 Amperometnc End Point
621 Perform steps 611-615 inclusive or follow the directions of the manufacturer of
the amperometnc titrator Prepackaged reagents should be checked
(restandardized)
622 Place the solution in the proper position on the amperometnc titrater
623 Titrate with 0 0282N Iodine Solution (5 12) Observe the response of the meter
needle Initially the needle will remain stationary As the endpomt is approached
the needle will temporarily deflect, then return to or near to its original position
Continue dropwise When the needle deflects and remains deflected the end point
has been exceeded by one drop Subtract l/20th of an ml from the buret reading
and record the result
330 2-3
-------
7. Calculations
mg/lCl= (A - 5B) x 200
C i
where
A = ml000564NPAO
B = ml00282NI2
C = ml sample
Precision and Accuracy
8 1 Starch-Iodine Endpoint
811 Precision
In a single operator, single laboratory situation the following results were obtained
Sample
Matnx
Distilled Water*
Drinking Water
River Water
Domestic Sewageb
Raw Sewage
Average
mg/1
041
351
084
084
087
055
Stand Dev
±mg/l
005
012
004
002
007
009
Rel Stand Dev
122
33
43
27
76
160
•Three replicates for distilled water Seven replicates for other sample matrices
bSecondary treatment
1 • , i i , -
812 Accuracy (Relative)
For four samples the results were compared to the lodometnc titration as a means
of obtaining a relative accuracy
lodometnc
Sample
Matnx
Drinking Water
River Water
Domestic Sewage
Raw Sewage
Starch
Titration
mg/1
085
078
100
Approx 0 5
Iodide
Back Titration
mg/1
084
084
087
055
Recovery
988
1077
870
Approx 100 0
8 2 Amperometnc End Point
8 2 1 Precision
In a single operator, single laboratory situation the following results were obtained
330 2-4
-------
Sample Average Stand Dev Rel Stand
Matrix mg/1 ±mg/l Dev %
Distilled Water- 058 0 05 88
3 53 0 07 20
Drinking Water 0 82 0 05 59
River Water 0 68 , 0 06 94
Domestic Sewage" 1 10 0 09 83
"Three replicates for distilled water Seven replicates for other sample matrices
bSecondary treatment
822 Accuracy
For three samples the results were compared to the lodometnc titration as a means
of obtaining a relative accuracy
Amperometnc
lodometnc Back
Sample Titration Titration %
Matrix mg/1 mg/1 Recovery
Drinking Water 0 83 0 82 98 8
River Water 0 66 0 68 103 0
Domestic Sewage 145 1 10 75 7
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, 14th Ed , p 318, Method
409B "lodometnc Method II", (1975)
2 ASTM Standards, Part 31 "Water", p 276, Method D1253-76 (1976)
3 Bender, D F, "Comparison of Methods for the Determination of Total Available Residual
Chlorine in Various Sample Matrices", EPA Report-600/4-78-019
330 2-5
-------
CHLORINE, TOTAL RESIDUAL
Method 330.3 (Titrimetrfc, lodometric)
STORET NO. 50060
Scope and Application
1 1 The lodometric titration method is applicable to natural and treated waters at
concentrations greater than 0 1 mg/1
Summary of Method
2 1 Chlorine (hypochlonte ion, hypochlorous acid) and chlorammes stoichiometncally
liberate iodine from potassium iodide at pH 4 or less
2 2 The iodine is titrated with a standard reducing agent such as sodium thiosulfate or
phenylarsine oxide using a starch indicator
2 3 The results are calculated as mg/1 Cl even though the actual measurement is of total
oxidizing power because chlorine is the dominant oxidizing agent present
Interferences
3 1 Ferric, manganic and nitnte ions interfere, the neutral titration minimizes these
interferences
3 2 Acetic acid is used for the acid titration Sulfunc acid may be used if no interferences are
present Hydrochloric acid should never be used
3 3 Turbidity and color may make the endpomt difficult to detect Practice runs with spiked
samples may be necessay
Apparatus
4 1 Standard laboratory glassware is used A microburet 0-2 ml or 0-10 ml is used
depending on the desired range and accuracy
Reagents
5 1 Acetic acid, cone (glacial)
5 2 Potassium iodide, KI, crystals
5 3 Phenylarsine oxide (0 00564N) Wallace and Tiernan or equivalent Standardize with
potassium buodate (5 8, 5 12)
5 4 Phenylarsine oxide (0 0375N). Hach Chemical Co or equivalent Standardize with
potassium buodate (5 7, 5 13)
5 5 Commercially available starch indicators such as thyodene or equivalent may be used
5 6 Potassium buodate (0 IN) Dissolve 3 249 g potassium buodate, previously dried two
hours at 103°C, in distilled water and dilute to 1 0 liter Store in a glass stoppered bottle
5 7 Potassium buodate (0 05N) Dilute 500 ml of 0 1 N potassium buodate (5 6) to 1 liter in a
volumetric flask Store in glass stoppered bottle
5 8 Potassium buodate (0 005N) Dilute 50 ml of 0 1 N potassium buodate (5 6) to 1 liter in a
volumetric flask Store in glass stoppered bottle
Approved for NPDES
Issued 1978
330 3-1
-------
5.9 Standard iodine solution (0 IN) Dissolve 40 g KI m 25 ml distilled water, add 13 g
resubluned iodine and stir until dissolved Transfer to a 1 liter volumetric flask and dilute
to the mark Determine the exact normality (5 14)
5 10 Standard iodine titrant (0 0282N) Dissolve 25 g KI in a little distilled water in a 1 liter
volumetric flask Add the calculated amount of 0 1 N standard iodine to produce a
0.0282 N solution Standardize daily (5 15) Store in amber bottle or in dark, protect
from sunlight at all times and keep from contact with rubber
5.11 Sulfunc acid solution (1 4) Slowly add 200 ml H2SO4 (sp gr 1 84) to 800 ml of distilled
water
5 12 Standardization of 0 00564N phenylarsme oxide Dissolve approximately 2 g (±1 g) KI
(5 2) in 100 to 150 ml distilled water, add 10 ml H2SO4 solution (5 11) followed by 20 ml
0 005 N potassium biiodate solution (5 8) Place in dark for 5 minutes, dilute to 300 ml
and titrate with 0 00564N phenylarsme oxide solution (5 3) to a pale straw color Add a
small scoop of indicator (5 5) Wait until homogeneous blue color develops and continue
the titration drop by drop until the color disappears Run in duplicate Duplicate
determination should agree within ±0 05 ml
N P AO = 20 x 0 005
mlPAO
Adjust PAO solution if necessary and recheck
5 13 Standardization of 00375N phenylarsme oxide Dissolve approximately 2 g (±1 g) KI
(5 2) in 100 to 150 ml distilled water, add 10 ml H2SO4 solution (5 11) followed by 20 ml
0 05 N potassium bnodate solution (5 7) Place m dark for 5 minutes, dilute to 300 ml and
titrate wth 0 0375 N phenylarsme oxide solution (5 4) to a pale straw color Add a small
scoop of indicator (5 5) Wait until homogeneous blue color develops and continue the
titration drop by drop until the color disappears Run in duplicate Duplicate
determinations should agree within ±0 05 ml
NPAO== 20X01
ml PAO
Adjust PAO solution if necessary and recheck
i
5 14 Standardization of 0 1 N iodine solution Dissolve approximately 2 g (±1 g) KI (5 2) in
100 to 150 ml distilled water, add 20 ml iodine solution (5 9) Dilute to 300 ml and titrate
with 0 0375 N phenylarsme oxide solution (5 4) to a pale straw color Add a small scoop
of indicator (5 5) Wait until homogeneous blue color develops and continue the titration
drop by drop until the color disappears Run in duplicate Duplicate determinations
should agree within ±0 05 ml
M ml PAO X 0 0375
N'* = 20
330 3-2
-------
Adjust iodine solution if necessary and recheck
i
5 15 Standardization of 0 0282N iodine solution Dissolve approximately 2 g (±1 g) KI (5 2)
in 100 to 150 ml distilled water, add 20 ml iodine solution (5 10) Dilute to 300 ml and
titrate with 0 0375 N phenylarsine oxide solution (5 4) to a pale straw color Add a small
scoop of indicator (5 5) Wait until homogeneous blue color develops and continue the
titration drop by drop until the color disappears Run in duplicate Duplicate
determinations should agree within ±0 05 ml
XT ml PAO x 0 0375
^'* = 20
Adjust iodine solution if necessary and recheck
Procedure
6 1 This procedure gives a convenient direct reading (ml titrant = mg/1 Cl) in the range of
the microburet (0 5 ml to 2,5 or 10 ml) The sample volume and reagent normalities may
be varied at the analyst's discretion
6 2 Place 5 ml acetic acid in an Erlenmeyer flask containing a Teflon coated magnetic
stirring bar
6 3 Add about 1 g KI (5 2) estimated on a spatula
6 4 Add 200 ml sample
6 5 Place on magnetic stirrer under buret
6 6 Titrate away from direct sunlight with 0 00564N PAO (5 3) to a pale straw color Add a
scoop of indicator (5 5) Wait until blue color is homogeneously distributed, continue
titrating until blue color is discharged The ml of PAO is equal to the mg/1 Cl plus or
> minus the blank correction (6 7) if any
6 7 Blank titration Using distilled water in place of the sample perform steps 6 2-6 5, add a
scoop of indicator Perform either 6 7 1 or 6 7 2 depending on color development
6 7 1 Blank titration A If a blue color develops titrate with 0 00564N PAO (5 3) to the
disappearance of the blue color and record the results
672 Blank titration B If no blue color develops titrate with 0 0282N iodine (5 10) until
blue color appears Back titrate with 0 005 64N PAO (5 3) and record the
difference as titration B
Calculations
7 1 The ml of PAO titrant is equal to mg/1 Cl under the volumes and 'concentrations
described The blank correction A (671) can be directly subtracted The blank
correction B (6 7 2), which is added, involves a factor of 5 (unless one substitutes
0 00564N iodine for the 0 0282N iodine) Normally the reagents are pure enough that the
blank correction is insignificant and therefore unnecessary
330 3-3
-------
8 Precision and Accuracy
Thirty to thirty two laboratories analyzed prepared samples of 0 64, 0 84 and 1 83 mg/1 The
relative standard deviations were 27 0%, 32 4% and 23 6% respectively and relative errors
were 23 6%, 18 5%, and 16 7% respectively
In a single operator, single laboratory, situation the following results were obtained
Sample matrix Average Standard Rel standard
mg/1 deviation deviation
±mg/l %
Distilled Water* 0 25 0 001 0 23
4 02 0 03 0 76
Drinking Water 0 68 0 04 52
River water 0 30 0 03 97
Domestic Sewage* 111 006 59
Raw sewage 048 009 180
•Three repjicates for distilled water Seven replicates for other sample matrices
»>Secondary treatment
Bibliography
1. Standard Methods for the Examination of Water and Wastewater, 14th ed p 316, Method
409A "lodometnc Method I" (1975)
2. ASTM Standards, Part 31, "Water", p 276, Method D1253-76 (1976)
3 Bender, D F, "Comparison of Methods for the Determination of Total Available Residual
Chlorine in Various Sample Matrices", EPA Report-600/4-78-019
330 3-4
-------
CHLORINE, TOTAL RESIDUAL
Method 330.4 (Titrimetric, DPD-FAS)
STORET NO. 50060
1 Scope and Application
1 1 The N,N-diethyl-p-phenylene diamme (DPD) - ferrous ammonium sulfate (FAS)
titration method is applicable to natural and treated waters at concentrations above 0 1
mg/1 Cl
2 Summary of Method
2 1 Chlorine (hypochlonte ion, hypochlorous acid) and chlorammes stoichiometncally
liberate iodine from potassium iodide at pH 4 or less
' 2 2 The iodine is titrated with FAS using DPD as the indicator
2 3 The results are calculated as mg/1 Cl even though the actual measurement is of total
oxidizing power because chlorine is the dominant oxidizing agent present
3 Interferences
3 1 Bromine, bromamme and iodine are interferences which are normally present in
insignificant amounts
3 2 Oxidized manganese interferes but can be corrected by subtraction after performing a
titration in the presence of sodium arsemte (NaAsO2)
3 3 Copper interferes but is accounted for (up to approximately 10 mg/1 copper) by
incorporation of EDTA The EDTA also retards detenoration of DPD due to oxidation
and completely suppresses dissolved oxygen errors by preventing trace metal catalysis
3 4 Turbidity and color may make the endpoint difficult to detect Practice runs with spiked
samples may be necessary
4 Apparatus
4 1 Standard laboratory glassware is used A microburet, 0-2 ml or 0-10 ml, depending on
the concentration range expected, is used
5 Reagents
5 1 Phosphate buffer solution Dissolve 24 g anhydrous disodium hydrogen phosphate,
Na2HPO4, and 46 g anhydrous potassium dihydrogen phosphate, KH2PO4, in distilled
water Dissolve 800 mg disodium ethylenediamme tetraacetate dihydrate in 100 ml
distilled water Combine these two solutions and dilute to 1 liter with distilled water
Add 20 mg HgCl2 as a preservative
5 2 N,N-Diethyl-p-phenylenediarmne (DPD) indicator solution Dissolve 1 g DPD oxalate
or 1 5 g p-amino-N,N-diethylamlme sulfate in chlorine free distilled water containing 8
ml of 1 + 3 H2SO4 and 200 mg disodium ethylenediamme tetraacetate dihydrate Dilute
to 1 liter, store in a colored, glass-stoppered bottle Discard when discolored The buffer
and indicator sulfate are available as a combined reagent in stable powder form
CAUTION The oxalate is toxic, avoid ingestion
Approved for NPDES
Issued 1978
3304-1
-------
5 3 Standard ferrous ammonium sulfate (FAS) titrant Dissolve 1 106g Mohr's salt
Fe(NH4)2(SO4)2«6H2O, in distilled water containing 1 ml of 1 + 3 H2SO4 (5 4) and make
up to 1 liter with freshly boiled and cooled distilled water Stable for one month Check
with titration by standard potassium dichomate (5 5) The FAS titrant is equivalent to
lOOugCl/lOOml
54 Sulfunc acid solution (1+3) Slowly add one part of H2SO4(sp gr 1 84) to three parts of
distilled water
5 5 Potassium dichromate (0 1OOON) Dissolve 4 904 g potassium dichromate (KaCraOy) in
distilled water and dilute to 1 liter
5 6 Potassium Iodide, KI Crystals
5 7 Sodium Arsemte Solution Place 500 mg of sodium arsemte (NaAsO2) in a flask and
dilute to 100 ml with distilled water
6 Procedure
6 1 This procedure gives a convenient direct reading (ml titrant = mg/1 Cl) up to 4 mg/1
An aliquot should be diluted to 100 ml if higher concentrations are present
6 2 Place 5 ml of phosphate buffer (5 1) in a titration flask
6 3 Add 5 ml of DPD indicator (5 2)
6 4 Add approximately 1 g of KI (5 6) on a scoop
6 5 Add 100 ml of sample
6 6 Wait 2 minutes
6 7 Titrate with FAS (5 3) until the red color is discharged Record the volume of titrant
used
6 8 If oxidized manganese is present
681 Place 5 ml of phosphate buffer (5 1) in a titration flask
682 Add one small crystal of potassium iodide (5 6)
683 Add 0 5 ml of sodium arsemte solution (5 7)
684 Add 100 ml of sample Mix
685 Add 5 ml DPD indicator (5 2) Mix
6.8 6 Titrate wth FAS (5 3) until the red color is discharged Record the volume of
titrant used
7 Calculations
7 1 The ml of FAS titrant is equal to the mg/1 Cl If oxidized manganese was present,
subtract the'amount of titrant used in 6 8 6 from the amount of titrant used in 6 7 to
obtain the mg/1 Cl
8. Precision and Accuracy
Nineteen laboratories analyzed prepared samples of 0 64 and 1 83 mg/1 Cl The relative
standard deviations were 19 2 and 9 4% respectively and the relative errors were 8 1 and 4 3%
respectively
3304-2
-------
In a single operator single laboratory situation the following results were obtained
Sample
Matrix
Distilled Water*
Drinking Water
River Water
Domestic Sewage
Raw Sewage
Average
mg/1
034
065
345
098
079
108
079
Stand Dev
±mg/l
002
0003
002
001
001
002
003
Rel Stnd Dev
56
05
05
12
14
18
33
-------
CHLORINE, TOTAL RESIDUAL
Method 330.5 (Spectrophotometric, DPD)
STORET NO. 50060
Scope and Application
1 1 The DPD-Colonmetric method is applicable to natural and treated waters at
concentrations from 0 2-4 mg/1
Summary of Method
2 1 Chlorine (hypochlonte ion, hypochlorous acid) and chlorammes stoichiometncally
liberate iodine from potassium iodide at pH 4 or less
2 2 The liberated iodine reacts with N,N-diethyl-p-phenylene diamine (DPD) to produce a
red colored solution
2 3 The solution is spectrophotometncally compared to a series of standards, using a graph
or a regression analysis calculation
2 4 The results are read or calculated into mg/1 Cl
Interferences
3 1 Any oxidizing agents, these are usually present at insignificant concentrations compared
to the residual chlorine concentrations
3 2 Turbidity and color will essentially prevent the colonmetric analysis
Apparatus
4 1 Spectrophotometer for use at 515 nm and cells of light path 1 cm or longer
Reagents
5 1 Phosphate buffer solution Dissolve 24 g anhydrous disodium hydrogen phosphate,
Na2HPO4, and 46 g anhydrous potassium dihydrogen phosphate, KH2PO4, in distilled
water Dissolve 800 mg disodium ethylenediamme tetraacetate dihydrate in 100 ml
distilled water Combine these two solutions and dilute to 1 liter with distilled water
Add 20 mg Hg Ci2 as a preservative
5 2 N,N-Diethyl-p-phenylenediamme (DPD) indicator solution Dissolve 1 g DPD oxalate
or 1 5 g p-amino-N,N-diethylanihne sulfate in chlorine free distilled water containing 8
ml of 1 +3 H2SO4 (5 3) and 200 mg disodium ethylenediamme tetraacetate dihydrate
Dilute to 1 liter, store in a colored, glass-stoppered bottle Discard when discolored The
buffer and indicator sulfate are available as a combined reagent in stable powder form
CAUTION The oxalate is toxic, avoid mgestion
5 3 Sulfunc acid solution (1+3) Slowly add one part of H2SO4 (sp gr 1 84) to three parts
of distilled water
5 4 Potassium Iodide, KI crystals
5 5 Stock Potassium Permanganate Solution Place 0 891 g KMnO4 m a volumetnc flask and
dilute to 1 liter
Approved for NPDES
Issued 1978
330 5-1
-------
5 6 ' Standard Potassium Permanganate Solution Dilute 10 00 ml of stock potassium
permanganate splution (5 5) to 100 ml with distilled water in a volumetric flask One
millihter of this solution diluted to 100 ml with distilled water is equivalent to 1 00 mg/1
Cl
6. Procedure
6 1 Calibration
611 Prepare a series of permanganate standards covering the chlorine equivalent range
of 005 to 4 mg/1
6 1 2 Place 5 ml phosphate buffer (5 1) in a flask
6 1 3 Add 5 ml DPD reagent (5 2)
614 Add 100 ml permanganate standard (611)
615 Read at 515 nm on a spectrophotometer and record the absorbance
616 Return the contents of the cell to the flask
617 Titrate the contents of the flask with standard ferrous ammonium sulfate (DPD-
FAS Method), until the red color is discharged Record the result
62 Sample Analysis
6 2 1 Place 0 5 ml phosphate buffer (5 1) in flask
622 Add 0 5 ml DPD reagent (5 2)
623 Add approximately 0 1 g KI (5 4)
624 Add 10 ml of sample
625 Let stand 2 minutes
626 Read at 515 nm on a spectrophotometer, and record the absorbance
7. Calculations
7.1 Calibration Curve Method
711 Plot the absorbance of the standard permanganate solutions (6 1 5) on the vertical
axis versus the titrated concentration (6 1 7) on the horizontal axis
712 Draw the line of best fit through the points
713 Locate the absorbance (6 2 6) of the sample on the vertical axis
714 Read the concentration on the horizontal axis at the intersect of the absorbance
and the calibration line
7.2 Regression Analysis Calculation-Computerized
721 Enter the absorbance data of the standard permanganate solutions (6 1 5) and the
respective titrated concentrations (6 1 7) in the appropriate places in the program
722 Enter the absorbance data of the sample
723 The computer will then display the concentration in mg/1 Cl
8 Precision and Accuracy
Twenty-five laboratories analyzed prepared samples of 0 66 mg/1 Cl The relative standard
deviation was 27 6% and the relative error was 15 6%
330 5-2
-------
In a single laboratory, single operator situation the following results were obtained
Sample Average Stnd Deva Rel Stnd Dev»i
Matrix mg/1 ±|mg/l %
Distilled Water* 0 39 0 012 31'
361 Oil 32
Drinking Water 0 94 0 008 08
River Water 0 86 0 02 19
Domestic Sewage 107 0 03 24
t i- jf
"Three replicates for distilled water Seven replicates for other samples
For three samples the results were compared to the lodometnc titration as a means of obtaining a
relative accuracy
s
Sample lodometnc DPD % Recovery
Matrix Titration Colorime-
mg/1 tnc mg/1
Drinking Water 0 86 0 94 109 3
River Water 0 70 0 86 122 9
Domestic Sewage 101 107 106 0
Bibliography
Standard Methods for the Examination of Water and Wastewater, 14th Ed, Pg 332, Method
409F, "DPD Colonmetnc Method", (1975)
Bender, D F, "Comparison of Methods for the Determination of Total Available Residual
Chlorine in Various Sample Matrices", EPA Report-600/4-78-019
330 5-3
-------
CYANIDES, AMENABLE TO CHLORINATION
Method 335.1 (Titrimetric; Spectrophotometric)
STORET NO. 00722
Scope and Application
1 1 This method is applicable to the determination of cyanides amenable to chlormation in
drinking, surface and saline waters, domestic and industrial wastes
1 2 The titration procedure is used for measuring concentrations of cyanide exceeding 1
mg/1 after removal of the cyanides amenable to chlormation Below this level the
colonmetnc determination is used
Summary of Method
21 A portion of the sample is chlorinated at a pH > 11 to decompose the cyanide Cyanide
levels in the chlorinated sample are then determined by the method for Cyanide, Total, m
this manual Cyanides amenable to chlormation are then calculated by difference
Reagents
3 1 Calcium Hypochlonte solution Dissolve 5 g of calcium hypochlonte (Ca(OCl)2) in 100
ml of distilled water
3 2 Sodium Hydroxide solution Dissolve 50 g of sodium hydroxide (NaOH) in distilled
water and dilute to 1 liter
3 3 Ascorbic acid crystals
3 4 Potassium Iodide-starch test paper
Procedure
4 1 Two sample ahquots are required to determine cyanides amenable to chlormation To
one 500 ml aliquot or a volume diluted to 500 ml, add calcium hypochlonte solution (3 1)
dropwise while agitating and maintaining the pH between 11 and 12 with sodium
hydroxide (3 2)
Caution The initial reaction product of alkaline chlormation is the very toxic gas
cyanogen chloride, therefore, it is recommended that this reaction be performed m a
hood For convenience, the sample may be agitated in a 1 liter beaker by means of a
magnetic stirring device
4 2 Test for residual chlorine with Kl-starch paper (3 4) and maintain this excess for one
hour, continuing agitation A distinct blue color on the test paper indicates a sufficient
chlorine level If necessary, add additional hypochlonte solution
4 3 After one hour, add 0 5 g portions of ascorbic acid (3 3) until Kl-starch paper shows no
residual chlorine Add an additional 0 5 g of ascorbic acid to insure the presence of excess
reducing agent
44 Test for total cyanide in both the chlorinated and unchlormated ahquots as in the
method Cyanide, Total, in this manual
Approved for NPDES
Issued 1974
335 1-1
-------
5. Calculation
5.1 Calculate the cyanide amendable to chlormation as follows
CN,mg/l = A-B
where
A = mg/1 total cyanide m unchlonnated aliquot
B = mg/1 total in chlorinated aliquot
Bibliography
1. Annual Book of ASTM Standards, Part 31, "Water", Standard D 2036-75, Method B, p 505
(1976)
2. Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 376 and 370,
Method 413F and D (1975)
335 1-2
-------
CYANIDE, TOTAL
Method 335.2 (Titrimetric; Spectrophotometric)
STORET NO. 00720
i
1 Scope and Application
1 1 This method is applicable to the determination of cyanide in drinking, surface and saline
waters, domestic and industrial wastes
, 1 2 The titration procedure using silver nitrate with p-dimethylammo-benzal-rhodanme
indicator is used for measuring concentiations of cyanide exceeding 1 mg/1 (0 25
mg/250 ml of absorbing liquid)
1 3 The colorimetnc procedure is used for concentrations below 1 mg/1 of cyanide and is
sensitive to about 0 02 mg/1
2 Summary of Method
2 1 The cyanide as hydrocyanic acid (HCN) is released from cyanide complexes by means of
a reflux-distillation operation and absorbed m a scrubber containing sodium hydroxide
solution The cyanide ion in the absorbing solution is then determined by volumetric
titration or colonmetncally
22 In the colonmetnc measurement the cyanide is converted to cyanogen chloride, CNC1,
by reaction with chloramme-T at a pH less than 8 without hydrolyzmg to the cyanate
After the reaction is complete, color is formed on the addition of pyridme-pyrazolone or
pyridme-barbitunc acid reagent The absorbance is read at 620 nm when using pyridme-
pyrazolone or 578 nm for pyndme-barbitunc acid To obtain colors of comparable
intensity, it is essential to have the same salt content in both the sample and the
standards
2 3 The titnmetnc measurement uses a standard solution of silver nitrate to titrate cyanide in
the presence of a silver sensitive indicator
3 Definitions
3 1 Cyanide is defined as cyanide ion and complex cyanides converted to hydrocyanic acid
(HCN) by reaction in a reflux system of a mineral acid in the presence of magnesium ion
4 Sample Handling and Preservation
4 1 The sample should be collected in plastic or glass bottles of 1 liter or larger size All
bottles must be thoroughly cleansed and thoroughly rinsed to remove soluble material
from containers
4 2 Oxidizing agents such as chlorine decompose most of the cyanides Test a drop of the
sample with potassium iodide-starch test paper (Kl-starch paper), a blue color indicates
the need for treatment Add ascorbic acid, a few crystals at a time, until a drop of sample
produces no color on the indicator paper Then add an additional 0 06 g of ascorbic
acid for each liter of sample volume
Approved for NPDES
Issued 1974
Editorial revision 1974 and 1978
Technical Revision 1980
335 2-1
-------
4 3 Samples must be preserved with 2 ml of 10 N sodium hydroxide per liter of sample
(pH > 12) at the time of collection
4 4 Samples should be analyzed as rapidly as possible after collection If storage is required,
the samples should be stored in a refrigerator or in an ice chest filled with water and ice to
maintain temperature at 4°C
5. Interferences
5 1 Interferences are eliminated or reduced by using the distillation procedure described
in Procedure 8 1, 8 2 and 8 3
5 2 Sulfides adversely affect the colorimetric and titration procedures Samples that
contain hydrogen sulfide, metal sulfides or other compounds that may produce
hydrogen sulfide during the distillation should be distilled by the optional procedure
described in Procedure 8 2 The apparatus for this procedure is shown in Figure 3
5 3 Fatty acids will distill and form soaps under the alkaline titration conditions, making the
end point almost impossible to detect
5 3 1 Acidify the sample with acetic acid (1 + 9) to pH 6 0 to 7 0
Caution This operation must be performed in the hood and the sample left there
until it can be made alkaline again after the extraction has been performed
532 Extract with iso-octane, hexane, or chloroform (preference m order named) with a
solvent volume equal to 20% of the sample volume One extraction is usually
adequate to reduce the fatty acids below the interference level Avoid multiple
extractions or a long contact time at low pH in order to keep the loss of HCN at a
minimum When the extraction is completed, immediately raise the pH of the
sample to above 12 with NaOH solution
5.4 High results may be obtained for samples that contain nitrate and/or nitrite During
the distillation nitrate and nitrite will form nitrous acid which will react with some
organic compounds to form oximes These compounds formed will decompose under
test conditions to generate HCN The interference of nitrate and nitrite is eliminated
b} pretreatment with sulfamic acid
6. Apparatus
6 1 Reflux distillation apparatus such as shown in Figure 1 or Figure 2 The boiling flask
should be of 1 liter size with inlet tube and provision for condenser The gas absorber may
be a Fisher-Milligan scrubber
6 2 Microburet, 5 0 ml (for titration)
6 3 Spectrophotometer suitable for measurements at 578 nm or 620 nm with a 1 0 cm cell or
larger
6 4 Reflux distillation apparatus for sulfide removal as shown in Figure 3 The boiling
flask same as 6 1 The sulfide scrubber may be a Wheaton Bubber #709682 with 29/42
joints, size 100 ml The air inlet tube should not be fritted The cyanide absorption
vessel should be the same as the sulfide scrubber The air inlet tube should be fritted
6 5 Flow inetei, such as Lab Crest with stainless steel float (Fisher 11-164-50)
7. Reagents
7.1 Sodium hydroxide solution, 1 25N Dissolve 50 g of NaOH in distilled water, and dilute
to 1 liter with distilled water
335 2-2
-------
7 2 Lead acetate Dissolve 30 g of Pb (C2H3O2)«3H2O in 950 ml of distilled water Adjust
the pH to 4 5 with acetic acid Dilute to 1 liter
7 5 Sulfunc acid, 18N Slowly add 500 ml of concentrated H2SO4 to 500 ml of distilled
water
7 6 Sodium dihydrogenphosphate, 1 M Dissolve 138 g of NaH2PO4-H2O m 1 liter of
distilled water Refrigerate this solution
7 7 Stock cyanide solution Dissolve 2 51 g of KCN and 2 g KOH in 900 ml of distilled
water Standardize with 0 0192 N AgNO3 Dilute to appropriate concentration so that
1 ml = 1 mg CN
7 8 Standard cyanide solution, intermediate Dilute 100 Oml of stock (1 ml = 1 mgCN)to
1000 ml with distilled water (1 ml = 100 0 ug) ' ' '
7 9 Working standard cyanide solution Prepare fresh daily by diluting 100 0 ml of
intermediate cyanide solution to 1000 ml with distilled water and store in a glass
stoppered bottle 1 ml = 10 0 ug CN
7 10 Standard silver nitrate solution, 0 0192 N Prepare by crushing approximately 5 g
AgNO3 crystals and drying to constant weight at 40°C Weigh out 3 2647 g of dried
AgNO3, dissolve m distilled water, and dilute to 1000 ml (1 ml = Img CN)
711 Rhodanme indicator Dissolve 20 mg of p-dimethyl-ammo-benzalrhodanme m 100 ml of
acetone
7 12 Chloramme T solution Dissolve 1 0 g of white, water soluble Chloramme T in 100 ml of
distilled water and refrigerate until ready to use Prepare fresh daily
713 Color Reagent — One of the following may be used
7131 Pyndme-Barbitunc Acid Reagent Place 15 g of barbituric acid in a 250 ml
volumetric flask and add just enough distilled water to wash the sides of the
flask and wet the barbituric acid Add 75 ml of pyndme and mix Add 15 ml
of cone HC1, mix, and cool to room temperature Dilute to 250 ml with
distilled water and mix This reagent is stable for approximately six months
if stored in a cool, dark place
7 13 2 Pyndme-pyrazolone solution
71321 3-Methyl-l-phenyl-2-pyrazolm-5-one reagent, saturated solution Add
0 25 g of 3-methyl-l-phenyl-2-pyrazolm-5-one to 50 ml of distilled
water, heat to 60°C with stirring Cool to room temperature
71322 3,3'Dimethyl-l, l'-diphenyl-[4,4'-bi-2 pyrazolme]-5,5'dione (bispyra-
zolone) Dissolve 0 01 g of bispyrazolone m 10 ml of pyndme
71323 Pour solution (7 13 2 1) through non-acid-washed filter paper Collect
the filtrate Through the same filter paper pour solution (71322)
collecting the filtrate in the same container as filtrate from (7 13 2 1)
Mix until the filtrates are homogeneous The mixed reagent develops a
pink color but this does not affect the color production with cyanide if
used within 24 hours of preparation
7 14 Magnesium chloride solution Weight 510 g of MgCl2»6H2O into a 1000 ml flask, dissolve
and dilute to 1 liter with distilled water
715 Sulfamic acid i
335 2-3
-------
8. Procedure
8 I For samples without sulfide
8 1 1 Place 500 ml of sample, or an aliquot diluted to 500 ml in the 1 liter boiling
flask Pipet 50 ml of sodium hydroxide (7 1) into the absorbing tube If the
apparatus in Figure 1 is used, add distilled water until the spiral is covered
Connect the boiling flask, condenser, absorber and trap in the train (Figure 1
or 2)
812 Start a slow stream of air entering the boiling flask by adjusting the vacuum
source Adj ust the vacuum so that approximately two bubbles of air per second
enters the boiling flask through the air inlet tube Proceed to 8 4
8 2 For samples that contain sulfide
8.2 1 Place 500 ml of sample, or an aliquot diluted to 500 ml in the 1 liter boiling
flask PipetSO ml of sodium hydroxide (7 1) to the absorbing tube Add25mlof
lead acetate (7 2) to the sulfide scrubber Connect the boiling flask, condenser,
scrubber and absorber in the train (Figure 3) The flow meter is connected to the
outlet tube of the cyanide absorber
822 Start a stream of air entering the boiling flask by adjusting the vacuum source
Adjust the vacuum so that approximately 1 5 liters per minute enters the
boiling flask through the air inlet tube The bubble rate may not remain
constant while heat is being applied to the flask It may be necessary to readjust
the air rate occasionally Proceed to 8 4
83 If samples contain NO3 and or NO2 add 2 g of sulfamic acid solution (7 15) after the air
rate is set through the air inlet tube Mix for 3 minutes prior to addition of H2SO4
8 4 Slowly add 50 ml 18N sulfunc acid (7 5) through the air inlet tube Rinse the tube with
distilled water and allow the airflow to mix the flask contents for 3 mm Pour 20 ml of
magnesium chloride (7 14) into the air inlet and wash down with a stream of water
8 5 Heat the solution to boiling Reflux for one hour Turn off heat and continue the
airflow for at least 15 minutes After cooling the boiling flask, disconnect absorber and
close off the vacuum source
8 6 Drain the solution from the absorber into a 250 ml volumetric flask Wash the absorber
with distilled water and add the washings to the flask Dilute to the mark with distilled
water
8 7 Withdraw 50 ml or less of the solution from the flask and transfer to a 100 ml volumetric
flask If less than 50 ml is taken, dilute to 50 ml with 0 25N sodium hydroxide solution
(7 4) Add 15 0 ml of sodium phosphate solution (7 6) and mix
871 Pyridme-barbituric acid method Add 2 ml of chloramme T (7 12) and mix
See Note 1 After 1 to 2 minutes, add 5 ml of pyndine-barbitunc acid solution
(7 13 1) and mix Dilute to mark with distilled water and mix again Allow 8
minutes for color development then read absorbance at 578 nm in a 1 cm cell
within 15 minutes
872 Pyridine-pyrazolene method Add 0 5 ml of chloramme T (7 12) and mix See
Note 1 and 2 After 1 to 2 minutes add 5 ml of pyndme-pyrazolone solution
3352-4
-------
(7 13 1) and mix Dilute to mark with distilled water and mix again After 40
minutes read absorbance at 620 nm in a 1 cm cell
NOTE 1 Some distillates may contain compounds that have a chlorine
demand One minute after the addition of chloramme T, test for
residual chlorine with Kl-starch paper If the test is negative, add an
additional 0 5 ml of chlorine T After one minute, recheck the sample
NOTE 2 More than 05 ml of chloramme T will prevent the color from
developing with pyridme-pyrazolone
8 8 Standard curve for samples without sulfide
881 Prepare a series of standards by pipetmg suitable volumes of standard solution
(7 9) into 250 ml volumetric flasks To each standard add 50 ml of 1 25 N
sodium hydroxide and dilute to 250 ml with distilled water Prepare as follows
ML of Workmg Standard Solution Cone, fjg CN
(1 ml = 10 fjg CN) per 250 ml
0 BLANK
10 10
20 20
50 50
100 100
15 0 150
20 0 200
882 It is not imperative that all standards be distilled in the same manner as the
samples It is recommended that at least two standards (a high and low) be
distilled and compared to similar values on the curve to insure that the distil-
lation technique is reliable If distilled standards do not agree within ±10%
of the undistilled standards the analyst should find the cause of the apparent
error before proceeding
883 Prepare a standard curve by plotting absorbance of standard vs cyanide
concentrations
884 To check the efficiency of the sample distillation, add an increment of cyanide
from either the intermediate standard (7 8) or the working standard (7 9) to
500 ml of sample to insure a level of 20 //g/1 Proceed with the analysis as in
Procedure (811)
8 9 Standard curve for samples with sulfide
891 It is imperative that all standards be distilled in the same manner as the samples
Standards distilled by this method will give a linear curve, but as the concen-
tration increases, the recovery decreases It is recommended that at least 3
standards be distilled
892 Prepare a standard curve by plotting absorbance of standard vs cyanide con-
centrations
335 2-5
-------
8 10 Titrimetric method
8101 If the sample contains more than 1 mg/1 of CN, transfer the distillate or a
suitable aliquot diluted to 250 ml, to a 500 ml Erlenmeyer flask Add 10-12 drops
of the benzalrhodanme indicator
8102 Titrate with standard silver nitrate to the first change in color from yellow to
brownish-pink Titrate a distilled water blank using the same amount of sodium
hydroxide and indicator as in the sample
8.103 The analyst should familiarize himself with the end point of the titration and the
amount of indicator to be used before actually titrating the samples.
Calculation
91 If the colonmetnc procedure is used, calculate the cyanide, in ug/1, in the original
sample as follows
CN.zig/1 = A x 1,000 x 50
B C
where
A = ug CN read from standard curve
B = ml of original sample for distillation
C = ml taken for colonmetnc analysis
335 2-6
-------
9 2 Using the titnmetnc procedure, calculate concentration of CN as follows
* ® «-*-il y^T-inr c>o**^»^l^
250
ml ong sample ml of aliquot titrated
where
A = volume of AgNO3 for titration of sample
B = volume of AgNO3 for titration of blank
10 Precision and Accuracy
10 1 In a single laboratory (EMSL), using mixed industrial and domestic waste samples at
concentrations of 006, 0 13, 028 and 062 mg/1 CN, the standard deviations were
±0005, ±0007, ±0031 and ±0094, respectively.
10 2 In a single laboratory (EMSL), using mixed industrial and domestic waste samples at
concentrations of 0 28 and 0 62 mg/1 CN, recoveries were 85% and 102%, respectively
Bibliography
1 Bark, L S, and Higson, H G "Investigation of Reagents for the Colonmetric Determination
of Small Amounts of Cyanide", Talanta, 2 471-479 (1964)
2 Elly, C T "Recovery of Cyanides by Modified Serfass Distillation" Journal Water Pollution
Control Federation 40 848-856(1968)
3 Annual Book of ASTM Standards, Part 31, "Water", Standard D2036-75, Method A, p 503
(1976)
4 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 367 and 370,
Method 413B and D (1975)
5 Egekeze, J O , and Oehne, F W , "Direct Potentiometric Determination of Cyanide in
Biological Materials," J Analytical Toxicology, Vol 3, p 119, May/June 1979
6 Casey, J P , Bright, J W , and Helms, B D , "Nitrosation Interference in Distillation Tests
for Cyanide," Gulf Coast Waste Disposal Authority, Houston, Texas
335 2-7
-------
ALLIHN CONDENSER —
AIR INLET TUBE^
0
ONE LITER
BOILING FLASK
CONNECTING TUBING
SUCTION
FIGURE 1
CYANIDE DISTILLATION APPARATUS
335 2-8
-------
COOLING WATER
INLET
SCREW CLAMP
)
&
HEATER-*
TO LOW VACUUM
SOURCE
ABSORBER
DISTILLING FLASK
FIGURE 2
CYANIDE DISTILLATION APPARATUS
335 2-9
-------
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335.2-10
-------
CYANIDE, TOTAL
Method 335.3 (Colorimetric, Automated UV)
STORET NO. 00720
Scope and Application
1 1 This method is applicable to the determination of cyanide in drinking and surface waters,
domestic and industrial wastes
1 2 The applicable range is 5 to 500 ug/1
Summary of Methods
2 1 The cyanide as hydrocyanic acid (HCN), is released from cyanide complexes by means of
UV digestion and distillation Cyanides are converted to cyanogen chloride by reactions
with chloramme-T which subsequently reacts with pyridme and barbituric acid to give a
red-colored complex
Sample Handling and Preservation
3 1 The sample should be collected in plastic bottles of 1 liter or larger size All bottles must
be thoroughly cleansed and thoroughly rinsed to remove soluble material from
contamers
3 2 Samples must be preserved with 2ml of 10 N sodium hydroxide per liter of sample (pH
> 12) at the time of collection
,3 3 Samples should be analyzed as rapidly as possible after collection If storage is required,
the samples should be stored in a refrigerator or in an ice chest filled with water and ice to
- maintain temperature at 4°C
3 4 Oxidizing agents such as chlorine decompose most of the cyanides Test a drop of the
sample with potassium iodide-starch test paper (KI starch paper), a blue color indicates
the need for treatment Add ascorbic acid, a few crystals at a time, until a drop of sample
produces no color on the indicator paper Then add an additional 0 6 g of ascorbic acid
for each liter of sample volume
Interferences
4 1 Thiocyanates are a positive interference During the UV digestion thiocyanates are
decomposed to cyanide
4 2 Sulfides adversely affect the colonmetnc procedure If a drop of the sample on lead
acetate test paper indicates the presence of sulfide, treat 25 ml more of the stabilized
sample (pH > 12) than that required for the cyanide determination with powdered
cadmium carbonate Yellow cadmium sulfide precipitates if the sample contains sulfide
Repeat this operation until a drop of the treated sample solution does not darken the lead
acetate test paper Filter the solution through a dry filter paper into a dry beaker, and
from the filtrate, measure the sample to be used for analysis Avoid a large excess of
Issued 1978
335 3-1
-------
cadmium and a long contact time m order to minimize a loss by complexation or
occlusion of cyanide on the precipitated material
5. Apparatus
5 1 Techmcon AutoAnalyzer
511 Sampler
512 Manifold with UV digestor
513 Proportioning pump
514 Heating bath with distillation coil
5 1 5 Distillation head
5 1 6 Colorimeter equipped with a 15 mm flowcell and 570 nm filter
5 1 7 Recorder
6. Reagents
6 1 Distillation reagent Carefully add 250 ml of 85% phosphoric acid and 50 ml of
hypophosphorus acid to 700 ml of distilled water, mix and dilute to one liter with
distilled water
6 2 Phosphate buffer, pH 5 2 Dissolve 13 6 g of potassium dihydrogen phosphate and 0 28 g
of disodium phosphate in 900 ml of distilled water and dilute to one liter
6 3 Chloramme-T Dissolve 2 0 g of chloramme-T in 500 m 1 of distilled water
6 4 Pyndme barbituric acid reagent Place 15 g of barbituric acid in a one liter beaker Wash
the sides of the beaker with about 100 ml of distilled water Add 75 ml of pyndme and
mix Add 15 ml of cone HC1 and mix Dilute to about 900 ml with distilled water and
mix until all the barbituric acid has dissolved Transfer the solution to a one liter flask
and dilute to the mark
6 5 Sodium hydroxide, 1 N Dissolve 40 g of NaOH in 500 m 1 of distilled water and dilute to
one liter
6 6 Stock cyanide solution Dissolve 251 g of KCN and 2 g KOH m 900 ml of distilled
water and mix Dilute to one liter Standardize with 0 0192 N AgNO3 to appropriate
concentration 1 ml = 1 mgCN
6 7 All working standards should contain 2 m 1 of 1 N NaOH (6 5) per 100 m 1
7. Procedure
7.1 Set up the manifold as shown in Figure 1 m a hood or a well-ventilated area
7 2 Set temperature of the heating bath at 150°C
7 3 Allow colorimeter and recorder to warm up for 30 minutes Run a baseline with all
reagents, feeding distilled water through the sample line
74 Place appropriate standards in the sampler in order of decreasing concentration
Complete loading of sampler tray with unknown samples
7 5 When the baseline becomes steady begin the analyses
8. Calculation
8 1 Prepare standard curve by plotting peak heights of standards against concentration
values Compute concentrations of samples by comparing sample peak heights with
standards
9. Precision and Accuracy
9 1 Precision and accuracy data are not available at this time
335 3-2
-------
Bibliography
Technicon AutoAnalyzer II Methodology, Industrial Method No 315-74 WCUV digestion
and distillation, Technicon Industrial Systems, Tarrytown, N Y, 10591, (1974)
Goulden,P D, Afghan, B K and Brooksbank, P , Anal Chem^4,1845 (1972)
335 3-3
-------
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335 3-4
-------
FLUORIDE, TOTAL
Method 340.1 (Colorimetric, SPADNS with Bellack Distillation)
STORET NO. Total 00951
Dissolved 00950
Scope and Application
1 1 This method is applicable to the measurement of fluoride in drinking, surface, and saline
waters, domestic and industrial wastes
1 2 The method covers the range from 0 1 to about 1 4 mg/1 F This range may be extended
to 1000 mg/1 using the Fluoride Ion Selective Electrode Method (3402) after
distillation
Summary of Method
2 1 Following distillation to remove interferences, the sample is treated with the SPADNS
reagent The loss of color resulting from the reaction of fluoride with the zirconyl-
SPADNS dye is a function of the fluoride concentration
Comments
3 1 The SPADNS reagent is more tolerant of interfering matenals than other accepted
fluoride reagents Reference to Table 414 1, p 388, Standard Methods for the
Examination of Waters and Wastewaters, 14th Edition, will help the analyst decide if
distillation is required The addition of the highly colored SPADNS reagent must be
done with utmost accuracy because the fluoride concentration is measured as a difference
of absorbance in the blank and the sample A small error in reagent additon is the most
prominent source of error in this test
3 2 Care must be taken to avoid overheating the flask above the level of the solution This is
done by maintaining an even flame entirely under the boiling flask
Apparatus
4 1 Distillation apparatus A 1-liter round-bottom, long-necked pyrex boiling flask,
connecting tube, efficient condenser, thermometer adapter and thermometer reading to
200°C All connections should be ground glass Any apparatus equivalent to that shown
in Figure 1 is acceptable
42 Colorimeter One of the following
421 Spectrophotometer for use at 570 nm providing a light path of at least 1 cm
422 Filter photometer equipped with a greenish yellow filter having maximum
transmittance at 550 to 580 nm and a light path of at least 1 cm
Reagents
5 1 Sulfunc acid, H2SO4, cone
Approved for NPDES and SDWA
Issued 1971
Editorial revision 1974 and 1978
340 1-1
-------
5 2 Silver sulfate, Ag2SO4 crystals
5 3 Stock fluoride solution Dissolve 0 221 g anhydrous sodium fluoride, NaF, in distilled
water m a 1-liter volumetric flask and dilute to the mark with distilled water, 1 00 ml =
0 ImgF
5 4 Standard fluoride solution Place 100 ml stock fluoride solution (5 3) in a 1 liter
volumetric flask and dilute to the mark with distilled water, 1 00 ml = 0 010 mg F
5 5 SPADNS solution Dissolve 0 958 g SPADNS, sodium 2-(parasulfophenylazo)-l,8-
dmydroxy-3,6-naphthalene disulfonate, in distilled water in a 500 ml volumetric flask
and dilute to the mark Stable indefinitely if protected from direct sunlight
5 6 Zirconyl-acid reagent Dissolve 0 133 g zirconyl chloride octahydrate, ZrOCl2»8H2O m
approximately 25 ml distilled water in a 500 ml volumetric flask Add 350 ml cone HC1
and dilute to the mark with distilled water
5.7 Acid-zirconyl-SPADNS reagent Mix equal volumes of SPADNS solution (5 5) and
zirconyl-acid reagent (5 6) The combined reagent is stable for at least 2 years
5 8 Reference solution Add 10 ml SPADNS solution (5 5) to 100 ml distilled water Dilute 7
ml cone HC1 to 10 ml and add to the dilute SPADNS solution This solution is used for
zeroing the spectrophotometer or photometer It is stable and may be used indefinitely
5 9 Sodium arsenite solution Dissolve 5 0 g NaAsO2 m distilled water in a 1-liter volumetric
flask and dilute to the mark with distilled water (CAUTION Toxic-avoid mgestion)
Procedure
6 1 Preliminary distillation
611 Place 400 ml distilled water m the distilling flask
6 1 2 Carefully add 200 ml cone H2SO4 and swirl until contents are homogeneous
613 Add 25 to 35 glass beads, connect the apparatus (Figure 1) making sure all joints
are tight
6 1 4 Heat slowly at first, then as rapidly as the efficiency of the condenser will permit
(distillate must be cool) until the temperature of the flask contents reaches exactly
180°C Discard the distillate This process removes fluoride contamination and
adjusts the acid-water ratio for subsequent distillations
6 1 5 Cool to 120°C or below
6 1 6 Add 300 ml sample, mix thoroughly, distill as in 6 1 4 until temperature reaches
180°C Do not heat above 180°C to prevent sulfate carryover
617 Add Ag2SO4 (5 2) at a rate of 5 mg/mg Cl when high chloride samples are distilled
618 Use the sulfunc acid solution m the flask repeatedly until the contaminants from
the samples accumulate to such an extent that recovery is affected or interferences
appear in the distillate Check periodically by distilling standard fluoride samples
6 1 9 High fluoride samples may require that the still be flushed by using distilled water
and combining distillates
6 2 Colonmetnc Determination
621 Prepare fluoride standards in the range 0 to 1 40 mg/1 by diluting appropriate
quantities of standard fluoride solution (5 4) to 50 ml with distilled water
340 1-2
-------
CONNECTING TUBE
THERMOMETER ;
THERMOMETER ADAPTER
1-liter
ROUND BOTTOM
FLASK
ADAPTER
24/40
JOINT
CONDENSER
BURNER
3 00-ml
O VOLUMETRIC
FLASK
FIGURE 1 DIRECT DISTILLATION APPARATUS
FOR FLUORIDE.
340 1-3
-------
622 Pipet 5 00 ml each of SPADNS solution (5 5) and zirconyl-acid reagent (5 6) or
10 00 ml of the mixed acid-zirconyl-SPADNS reagent (5 7) to each standard and
mix well
623 Set photometer to zero with reference solution (5 8) and immediately obtain
absorbance readings of standards
624 Plot absorbance versus concentration Prepare a new standard curve whenever
fresh reagent is made
6 2 5 If residual chlorine is present pretreat the sample with 1 drop (0 05 ml) NaAsO2
solution (5 9) per 0 1 mg residual chlorine and mix Sodium arsemte
concentrations of 1300 mg/1 produce an error of 0 1 mg/1 at 1 0 mg/1 F
6 2 6 Use a 50 ml sample or a portion diluted to 50 ml Adjust the temperature of the
sample to that used for the standard curve
627 Perform step 6 2 2and 6 2 3
7. Calculations
7 1 Read the concentration in the 50 ml sample using the standard curve (6 2 4)
7 2 Calculate as follows
mg/1 F = x
8
ml sample
7 3 When a sample (ml sample) is diluted to a volume (B) and then a portion (C) is analyzed,
use
A F = mgFx 1,000 B
6 ml sample C
8. Precision and Accuracy
81 On a sample containing 0 83 mg/1 F with no interferences, 53 analysts using the Bellack
distillation and the SPADNS reagent obtained a mean of 0 81 mg/1 F with a standard
deviation of ±0089 mg/1
82 On a sample containing 057 mg/1 F (with 200 mg/1 SO4 and 10 mg/1 Al as
interferences) 53 analysts using the Bellack distillation obtained a mean of 0 60 mg/lF
with a standard deviation of ±0 103 mg/1
83 On a sample containing 0 68 mg/1 F (with 200 mg/1 SO4, 2 mg/1 Al and 2 5 mg/1
[Na(PO3)6] as interferences), 53 analysts using the Bellack distillation obtained a mean of
0.72 mg/1 F with a standard deviation of ±0 092 mg/1 (Analytical Reference Service,
Sample 111-B water, Fluoride, August, 1961)
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, p 389-390 (Method No
414A, Preliminary Distillation Step) and p 393-394 (Method 414C SPADNS) 14th Edition
(1975)
2 Annual Book of ASTM Standards, Part 31, "Water", Standard D 1179-72, Method A, p 310
(1976)
3401-4
-------
FLUORIDE
Method 340.2 (Potentiometric, Ion Selective Electrode)
STORET NO: Total 00951
Dissolved 00950
Scope and Application
1 1 This method is applicable to the measurement of fluoride m drinking, surface and saline
waters, domestic and industrial wastes
1 2 Concentration of fluoride from 0 1 up to 1000 mg/liter may be measured
1 3 For Total or Total Dissolved Fluoride, the Bellack distillation is required for NPDES
monitoring but is not required for SDWA monitoring
Summary of Method
2 1 The fluoride is determined potentiometncally using a fluoride electrode m conjunction
with a standard single junction sleeve-type reference electrode and a pH meter having an
expanded millivolt scale or a selective ion meter having a direct concentration scale for
fluoride
2 2 The fluoride electrode consists of a lanthanum fluoride crystal across which a potential is
developed by fluoride ions The cell may be represented by Ag/Ag Cl, Cr(0 3),
F(0 001) LaF/test solution/SCE/
Interferences
3 1 Extremes of pH interfere, sample pH should be between 5 and 9 Polyvalent cations of
Si+4, Fe+3 and Al+3 interfere by forming complexes with fluoride The degree of
interference depends upon the concentration of the complexmg cations, the
concentration of fluoride and the pH of the sample The addition of a pH 5 0 buffer
(described below) containing a strong chelating agent preferentially complexes
aluminum (the most common interference), silicon and iron and eliminates the pH
problem
Sampling Handling and Preservation
4 1 No special requirements
Apparatus
5 1 Electrometer (pH meter), with expanded mv scale, or a selective ion meter such as the
Orion 400 Series
5 2 Fluoride Ion Activity Electrode, such as Orion No 94-09(I>
5 3 Reference electrode, single junction, sleeve-type, such as Orion No 90-01, Beckman No
40454, or Corning No 476010
5 4 Magnetic Mixer, Teflon-coated stirring bar
Approved for NPDES and SDWA
Issued 1971
Editorial revision 1974
340 2-1
-------
6 Reagents
6.1 Buffer solution, pH 5 0-5 5 To approximately 500 ml of distilled water in a 1 liter beaker
add 57 ml of glacial acetic acid, 58 g of sodium chloride and 4 g of CDTA<2) Stir to
dissolve and cool to room temperature Adjust pH of solution to between 5 0 and 5 5 with
5 N sodium hydroxide (about 150 ml will be required) Transfer solution to a 1 liter
volumetric flask and dilute to the mark with distilled water For work with brines,
additional Nad should be added to raise the chloride level to twice the highest expected
level of chloride in the sample
6.2 Sodium fluoride, stock solution 1 0 ml = 0 1 mg F Dissolve 0 2210 g of sodium fluoride
in distilled water and dilute to 1 liter in a volumetric flask Store in chemical-resistant
glass or polyethylene
6 3 Sodium fluoride, standard solution 10ml = 001mgF Dilute 1000 ml of sodium
fluoride stock solution (6 2) to 1000 ml with distilled water
6 4 Sodium hydroxide, 5N Dissolve 200 g sodium hydroxide in distilled water, cool and
dilute to 1 liter
7. Calibration
7.1 Prepare a series of standards using the fluoride standard solution (6 3) in the range of 0 to
2 00 mg/1 by diluting appropriate volumes to 50 0 ml The following series may be used
i i|
Millimeters of Standard Concentration when Diluted
(1 0 ml = 0 01 mg/F) to 50 ml, mg F/hter
000 000
100 020
200 040
300 060
400 080
500 100
600 120
800 160
1000 200
7 2 Calibration of Electrometer Proceed as described in (8 1) Using semiloganthmic graph
paper, plot the concentration of fluoride in mg/hter on the log axis vs the electrode
potential developed in the standard on the linear axis, starting with the lowest
concentration at the bottom of the scale Calibration of a selective ion meter Follow the
directions of the manufacturer for the operation of the instrument
8 Procedure
8 1 Place 50 0 ml of sample or standard solution and 50 0 ml of buffer (See Note) in a 150 ml
beaker Place on a magnetic stirrer and mix at medium speed Immerse the electrodes in
the solution and observe the meter reading while mixing The electrodes must remain in
the solution for at least three minutes or until the reading has stabilized At
concentrations under 0 5 mg/liter F, it may require as long as five minutes to reach a
stable meter reading, high concentrations stabilize more quickly If a pH meter is used,
record the potential measurement for each unknown sample and convert the potential
3402-2
-------
reading to the fluoride ion concentration of the unknown using the standard curve If a
selective ion meter is used, read the fluoride level in the unknown sample directly in
mg/1 on the fluoride scale
NOTE: For industrial waste samples, this amount of buffer may not be adequate
Analyst should check pH first If highly basic ( >9), add 1 N HC1 to adjust pH to 8 3
9 Precision and Accuracy
91 A synthetic sample prepared by the Analytical Reference Service, PHS, containing 0 85
mg/1 fluoride and no interferences was analyzed by 111 analysts, a mean of 0 84 mg/1
with a standard deviation of ±0 03 was obtained
92 On the same study, a synthetic sample containing 0 75 mg/1 fluoride, 2 5 mg/1
polyphosphate and 300 mg/1 alkalinity, was analyzed by the same 111 analysts, a mean
of 0 75 mg/1 fluoride with a standard deviation of ±0 036 was obtained
Bibliography
1 PatentNo 3,431,182(March4,1969)
2 CDTA is the abbreviated designation of 1,2-cyclohexylene dimtnlo tetraacetic acid (The
monohydrate form may also be used ) Eastman Kodak 15411, Mallmckrodt2357, Sigma D
1383, Tridom-Fluka 32869-32870 or equivalent
3 Standard Methods for the Examination of Water and Wastewaters, p 389, Method No 414A,
Preliminary Distillation Step (Bellack), and p 391, Method No 414B, Electrode Method, 14th
Edition (1975)
4 Annual Book of ASTM Standards, Part 31, "Water", Standard D1179-72, Method B, p 312
(1976)
340 2-3
-------
FLUORIDE
Method 340.3 (Colorimetric, Automated Complexone)
STORET NO. Total 00951
Dissolved 00950
Scope and Application
1 1 This method is applicable to drinking, surface and saline waters, domestic and industrial
wastes The applicable range of the method is 0 05 to 1 5 mg F/l Twelve samples per
hour can be analyzed
1 2 For Total or Total Dissolved Fluoride, the Bellack Distillation must be performed on the
samples prior to analysis by the complexone method
Summary of Method
2 1 Fluoride ion reacts with the red cerous chelate of alizarin complexone It is unlike other
fluoride procedures in that a positive color is developed as contrasted to a bleaching
action in previous methods
Sample Handling and Preservation
3 1 No special requirements
Interferences
4 1 Method is free from most amonic and cationic interferences, except aluminum, which
forms an extremely stable fluoro compound, A1F6"3 This is overcome by treatment
with 8-hydroxyqumoline to complex the aluminum and by subsequent extraction with
chloroform At aluminum levels below 0 2 mg/1, the extraction procedure is not
required
Apparatus
5 1 Techmcon AutoAnalyzer Unit consisting of
5 1 1 Sampler I
5 1 2 Manifold
513 Proportioning pump
514 Continuous filter
515 Colorimeter equipped with 15 mm tubular flow cell and 650 nm filters
516 Recorder equipped with range expander
Reagents
6 1 Sodium acetate solution Dissolve 272 g (2 moles) of sodium acetate in distilled water and
dilute to 1 liter
6 2 Acetic acid-8-hydroxyquinohne solution Dissolve 6 g of 8-hydroxyqumoline in 34 ml of
cone acetic acid, and dilute to 1 liter with distilled water
Approved for NPDES
Issued 1971
340 3-1
-------
6 3 Chloroform Analytical reagent grade
6.4 Ammonium acetate solution (6 7%) Dissolve 67 g of ammonium acetate in distilled
water and dilute to 1 liter
6 5 Hydrochloric acid (2 N) Dilute 172 ml of cone HC1 to 1 liter
6 6 Lanthanum alizarin fluoride blue solution"' Dissolve 0 18 g of alizarin fluoride blue in a
solution containing 0 5 ml of cone ammonium hydroxide and 15 ml of 6 7% ammonium
acetate (6 4) Add a solution that contains 41 g of anhydrous sodium carbonate and 70 ml
of glacial acetic acid in 300 ml of distilled water Add 250 ml of acetone Dissolve 0 2 g of
lanthanum oxide in 12 5 ml of 2 N hydrochloric acid (6 5) and mix with above solution
Dilute to 1 liter
6 7 Stock solution Dissolve 2 210 g of sodium fluoride in 100 ml of distilled water and dilute
to 1 liter in a volumetric flask 1 0 ml = 10 mg F
6 8 Standard Solution Dilute 10 0 ml of stock solution to 1 liter in a volumetric flask 1 0
ml = OOlmgF
6 8 1 Using standard solution, prepare the following standards in 100 ml volumetric
flask
mg F/l ml Standard Solution/100 ml
005 05
010 10
020 20
040 40
060 60
080 80
100 100
1 20 12 0
1 50 150
Procedure
7.1 Set up manifold as shown m Figure 1
7 2 Allow both colorimeter and recorder to warm up for 30 minutes Run a baseline with all
reagents, feeding distilled water through the sample line Adjust dark current and
operative opening on colorimeter to obtain stable baseline
7 3 Place distilled water wash tubes in alternate openings in Sampler and set sample timing
at 2 5 minutes
7 4 Arrange fluoride standards in Sampler in order of decreasing concentration Complete
loading of Sampler tray with unknown samples
7 5 Switch sample line from distilled water to Sampler and begin analysis
Calculation
8 1 Prepare standard curve by plotting peak heights of processed fluoride standards against
concentration values Compute concentration of samples by comparing sample peak
heights with standard curve
340 3-2
-------
9 Precision and Accuracy
91 In a single laboratory (EMSL), using surface water samples at concentrations of 0 06,
0 15, and 1 08 mg F/l, the standard deviation was +0 018
92 In a single laboratory (EMSL), using surface water samples at concentrations of 0 14 and
1 25 mg F/l, recoveries were 89% and 102%, respectively
Bibliography
1 J T Baker Laboratory Chemical No Jl 12 or equivalent
2 Greenhaigh, R , and Riley, J P , "The Determination of Fluorides in Natural Waters, with
Particular Reference to Sea Water" Anal Chim Acta,25, 179(1961)
3 Chan, K M , and Riley, J P , "The Automatic Determination of Fluoride m Sea Water and
Other Natural Water" Anal Chim Acta, 35, 365(1966)
4 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 614,
Method 603, (1975)
340 3-3
-------
3403-4
-------
IODIDE
Method 345.1 (Titrimetric)
STORET NO. 71865
Scope and Application
1 1 This method is applicable to drinking, surface and saline waters, sewage and industrial
waste effluents
1 2 The concentration range for this method is 2-20 mg/1 of iodide
Summary of Method
2 1 After pretreatment to remove interferences, the sample is analyzed for iodide by
converting the iodide to lodate with bromine water and titrating with phenylarsme oxide
(PAO) or sodium thiosulfate
Sample Handling and Preservation
3 1 Store at 4°C and analyze as soon as possible
Interferences
A 1 Iron, manganese and organic matter can interfere, however, the calcium oxide
pretreatment removes or reduces these to insignificant concentrations
4 2 Color interferes with the observation of indicator and bromine-water color changes This
interference is eliminated by the use of a pH meter instead of a pH indicator and the use
of standardized amounts of bromine water and sodium formate solution instead of
observing the light yellow color changes
Reagents
5 1 Acetic Acid Solution (1 8) Mix 100 ml of glacial acetic acid with 800 ml of distilled
water
5 2 Bromine Water In a fume hood, add 0 2 ml bromine to 500 ml distilled water Stir with
a magnetic stirrer and a Teflon-coated stirring bar for several hours or until the bromine
dissolves Store in a glass-stoppered colored bottle
5 3 Calcium Oxide (CaO) Anhydrous, powdered
5 4 Potassium Iodide (KI) Crystals, ACS Reagent Grade
5 5 Sodium Acetate Solution (275 g/1) Dissolve 275 g of sodium acetate tnhydrate
(NaC2H3O2«3H2O) in distilled water Dilute to 1 liter and filter
5 6 Sodium Formate Solution (500 g/1) Dissolve 50 g of sodium formate (NaCHO2) in hot
distilled water and dilute to 100 ml
5 7 Nitrogen Gas Cylinder
5 8 Sulfunc Acid Solution (1 4) Slowly add 200 ml of H2SO4 (sp gr 1 84) to 800 ml of
distilled water
5 9 Phenylarsme Oxide (0 0375 N) Hach Chemical Co or equivalent Standardize with
0 0375 N potassium bnodate (5 15, 5 18)
Issued 1974
345 1-1
-------
5 10 Phenylarsme Oxide Working Standard (0 0075 N) Transfer 100 ml of commercially
available 0 0375 N phenylarsine oxide (5 9) to a 500 ml volumetric flask and dilute to the
mark with distilled water This solution should be prepared fresh daily
511 Commercially available starch indicators such as thyodene or equivalent may be used
5 12 Sodium Thiosulfate, Stock Solution, 075 N Dissolve 186 15 g (Na2S2O3«5H2O) m
boiled and cooled distilled water and dilute to 1 0 liter Preserve by adding 5 ml
chloroform
5 13 Sodium Thiosulfate Standard Titrant, 0 0375 N Prepare by diluting 50 0 ml of stock
solution to 1 0 liter Preserve by adding 5 ml of chloroform Standardize with 0 0375 N
potassium buodate (5 15,5 18)
5.14 Sodium Thiosulfate Working Standard (00075 N) Transfer 100 ml of sodium
thiosulfate standard titrant (5 13) to a 500 ml volumetric flask and dilute to the mark
with distilled water This solution should be prepared fresh daily
515 Potassium Buodate Standard, 00375 N Dissolve 4873 g potassium buodate,
previously dried 2 hours at 103°C, in distilled water and dilute to 1 0 liter Dilute 250 ml
to 1 0 liter for 0 0375 N buodate solution
5.16 Starch Solution Prepare an emulsion of 10 g of soluble starch in a mortar or beaker
with a small quantity of distilled water Pour this emulsion into 1 liter of boiling water,
allow to boil a few minutes, and let settle overnight Use the clear supernate This
solution may be preserved by the addition of 5 ml per liter of chloroform and storage in a
10°C refrigerator Commercially available, powdered starch indicators may be used in
place of starch solution
5.17 Potassium Fluoride (KF«2H2O) ACS Reagent Grade
518 Standardization of 0 0375 N Phenylarsme Oxide and 0 0375 N sodium
thiosulfate. Dissolve approximately 2 g (± 1 0 g) KI (5 4) m 100 to 150 ml distilled
water, add 10 ml H2SO4 solution (5 8) followed by 20 ml standard potassium buodate
solution (5 15) Place in dark for 5 minutes, dilute to 300 ml and titrate with phenylarsine
oxide (5 9) or sodium thiosulfate standard titrant (5 13) to a pale straw color Add a
small scoop of indicator (5 11) Wait until homogeneous color develops and continue the
titration drop by drop until the blue color disappears Run in duplicate Duplicate
determinations should agree within ±0 05 ml
Procedure
61 Pretreatment
6 1 1 Add a visible excess of CaO (5 3) to 400 ml of sample Stir or shake vigorously for
approximately 5 minutes Filter through a dry, moderately retentive filter paper,
discarding the first 75 ml
6 2 Iodide Determination
621 Place 100 ml of pretreated sample (6 1) or a fraction thereof diluted to that volume,
into a 150 ml beaker Add a Teflon-coated stirring bar and place on a magnetic
sturer Insert a pH electrode and adjust the pH to approximately 7 or slightly less
by the dropwise addition of H2SO4 solution (5 8)
622 Transfer the sample to a 250 ml wide-mouthed conical flask Wash beaker with
small amounts of distilled water and add washings to the flask
345 1-2
-------
NOTE A 250 ml iodine flask would increase accuracy and precision by
preventing possible loss of the iodine generated upon addition of potassium iodide
and sulfuric acid (631)
623 Add 15 ml sodium acetate solution (5 5) and 5 ml acetic acid solution (5 1) Mix
well Add 40 ml bromine water solution (5 2), mix well Wait 5 minutes
624 Add 2 ml sodium formate solution (5 6), mix well Wait 5 minutes
625 Purge the space above the sample with a gentle stream of nitrogen (5 7) for
approximately 30 seconds to remove bromine fumes
626 If a precipitate forms (iron), add 0 5 g KF«2H2O (5 17)
6 2 7 A distilled water blank must be run with each set of samples because of iodide in
reagents If a blank is consistently shown to be zero for a particular "lot" of
chemicals it can then be ignored
6 3 Titration
631 Dissolve approximately 1 g potassium iodide (5 4) in sample Add 10 ml of H2SO4
solution (5 8) and place in dark for 5 minutes
632 Titrate with phenylarsme oxide working standard (5 10) or sodium thiosulfate
working standard solution (5 14) adding indicator (5 11 or 5 15) as end point is
approached (light straw color) Titrate to colorless solution Disregard returning
blue color
Calculations
T / /1\ 11 nrrv
I-(mg/l) = 21,150
I ml X N \
I — y - \
where
ml = the number of ml of PAO needed to titrate the sample
N = the normality of the PAO used to titrate the sample
V = the volume of sample taken (100 ml or a fraction thereof)
21,150 was calculated from the number of equivalents of iodine produced when the potassium
iodide was added and from the rearrangement of the equation to produce the value in terms of
mg/1
Precision and Accuracy
81 In a single laboratory (EMSL), using a mixed domestic and industrial waste effluent, at
concentrations of 1 6, 4 1, 6 6, 11 6 and 21 6 mg/1 of iodide, the standard deviations
were ±023, ±017, ±010, ±006 and ±0 50 mg/1, respectively
82 In a single laboratory (EMSL), using a mixed domestic and industrial waste effluent at
concentrations of 4 1, 6 6, 11 6 and 216 mg/1 of iodide, recoveries were 80, 97, 97 and
92%, respectively
345,1-3
-------
Bibliography
1 Annual Book of ASTM Standards, Part 31 ".Water", Standard D1246-68, p 328, Method C
(1976)
2. Bender, D F, "Modification of the lodimetric Titration Method for the Determination of
Bromide and its Application to Mixed Domestic-Industrial Waste Effluent", Analyst
(London) 100, p400-404 (June 1975)
345-1-4
-------
NITROGEN, AMMONIA
Method 350.1 (Colorimetric, Automated Phenate)
STORET NO. Total 00610
Dissolved 00608
Scope and Application
1 1 This method covers the determination of ammonia in drinking, surface, and saline
waters, domestic and industrial wastes in the range of 0 01 to 2 0 mg/1 NH3 as N This
range is for photometric measurements made at 630-660 nm in a 15 mm or 50 mm
tubular flow cell Higher concentrations can be determined by sample dilution
Approximately 20 to 60 samples per hour can be analyzed
Summary of Method
2 1 Alkaline phenol and hypochlonte react with ammonia to form indophenol blue that is
proportional to the ammonia concentration The blue color formed is intensified with
sodium mtroprusside
Sample Handling and Preservation
3 1 Preservation by addition of 2 ml cone H2SO4 per liter and refrigeration at 4°C
Interferences
4 1 Calcium and magnesium ions may be present in concentration sufficient to cause
precipitation problems during analysis A 5% EDTA solution is used to prevent the
precipitation of calcium and magnesium ions from river water and industrial waste For
sea water a sodium potassium tartrate solution is used
4 2 Sample turbidity and color may interfere with this method Turbidity must be removed
by filtration prior to analysis Sample color that absorbs in the photometric range used
will also interfere
Apparatus
5 1 Techmcon AutoAnalyzer Unit (AAI or AAII) consisting of
511 Sampler
5 1 2 Manifold (AAI) or Analytical Cartridge (AAII)
513 Proportioning pump
5 1 4 Heating bath with double delay coil (AAI)
515 Colorimeter equipped with 15 mm tubular flow cell and 630-660 nm filters
516 Recorder
5 1 7 Digital printer for AAII (optional)
Approved for NPDES following preliminary distillation, Method 3502
Issued 1974
Editorial revision 1978
350 1-1
-------
Reagents
6 1 Distilled water Special precaution must be taken to insure that distilled water is free of
ammonia Such water is prepared by passage of distilled water through an ion exchange
column comprised of a mixture of both strongly acidic cation and strongly basic anion
exchange resins The regeneration of the ion exchange column should be carried out
according to the instruction of the manufacturer
NOTE 1: All solutions must be made using ammonia-free water
6 2 Sulfunc acid 5N Air scrubber solution Carefully add 139 ml of cone sulfunc acid to
approximately 50Q ml of ammonia-free distilled water Cool to room temperature and
dilute to 1 liter with ammonia-free distilled water
6 3 Sodium phenolate Using a 1 liter Erlenmeyer flask, dissolve 83 g phenol in 500 ml of
distilled water In small increments, cautiously add with agitation, 32 g of NaOH
Periodically cool flask under water faucet When cool, dilute to 1 liter with distilled
water
6 4 Sodium hypochlonte solution Dilute 250 ml of a bleach solution containing 5 25%
NaOCl (such as "Clorox") to 500 ml with distilled water Available chlorine level should
approximate 2 to 3% Since "Clorox" is a proprietary product, its formulation is subject
to change The analyst must remain alert to detecting any variation in this product
significant to its use in this procedure Due to the instability of this product, storage over
an extended period should be avoided
65 Disodium ethylenediamme-tetraacetate (EDTA) (5%) Dissolve 50 g of EDTA
(disodium salt) and approximately six pellets of NaOH m 1 liter of distilled water
NOTE 2: On salt water samples where EDTA solution does not prevent precipitation of
cations, sodium potassium tartrate solution may be used to advantage It is prepared as
follows
6 5 1 Sodium potassium tartrate solution 10% NaKC4H4O6«4H2O To 900 ml of
distilled water add 100 g sodium potassium tartrate Add 2 pellets of NaOH and a
few boiling chips, boil gently for 45 minutes Cover, cool, and dilute to 1 liter with
ammonia-free distilled water Adjust pH to 5 2 ±05 with H2SO4 After allowing to
settle overnight in a cool place, filter to remove precipitate Then add 1/2 ml Bnj-
35(4> (available from Techmcon Corporation) solution and store in stoppered bottle
6 6 Sodium nitroprusside (0 05%) Dissolve 0 5 g of sodium mtroprusside in 1 liter of
distilled water
6 7 Stock solution Dissolve 3 819 g of anhydrous ammonium chloride, NH4C1, dried at
105°C, in distilled water, and dilute to 1000 ml 1 0 ml = 1 0 mg NH3-N
6.8 Standard Solution A Dilute 10 0 ml of stock solution (6 7) to 1000 ml with distilled
water 1 0 ml = 0 01 mg NH3-N
6 9 Standard solution B Dilute 10 0 ml of standard solution A (6 8) to 100 0 ml with
distilled water 1 0 ml = 0 001 mg NH3-N
350 1-2
-------
6 10 Using standard solutions A and B, prepare the following standards in 100 ml volumetric
flasks (prepare fresh daily)
NH3-N. mg/1 ml Standard Solution/100 ml
Solution B
001 10
002 20
005 50
010 100
Solution A
020 20
050 50
080 80
1 00 10 0
1 50 15 0
2 00 20 0
NOTE 3: When saline water samples are analyzed, Substitute Ocean Water (SOW)
should be used for preparing the above standards used for the calibration curve,
otherwise, distilled water is used If SOW is used, subtract its blank background response
from the standards before preparing the standard curve
Substitute Ocean Water (SOW)
NaCl 24 53 g/1 NaHCO3 0 20 g/1
MgCl2 5 20 g/1 KBr 0 10 g/1
Na2SO4 409 g/1 H3BO3 003 g/1
CaCl2 1 16 g/1 SrCl2 0 03 g/1
KC1 0 70 g/1 NaF 0 003 g/1
Procedure
7 1 Since the intensity of the color used to quantify the concentration is pH dependent, the
acid concentration of the wash water and the standard ammonia solutions should
approximate that of the samples For example, if the samples have been preserved with 2
ml cone H2SO4/liter, the wash water and standards should also contain 2 ml cone
H2SO4/hter
7 2 For a working range of 0 01 to 2 00 mg NH3-N/1 (AAI), set up the manifold as shown in
Figure 1 For a working range of 01 to 1 0 mg NH3-N/1 (AAII), set up the manifold as
shown in Figure 2 Higher concentrations may be accommodated by sample dilution
7 3 Allow both colorimeter and recorder to warm up for 30 minutes Obtain a stable baseline
with all reagents, feeding distilled water through sample line
7 4 For the AAI system, sample at a rate of 20/hr, 1 1 For the AAII use a 60/hr 6 1 cam
with a common wash
350 1-3
-------
7 5 Arrange ammonia standards in sampler in order of decreasing concentration of nitrogen
Complete loading of sampler tray with unknown samples
7 6 Switch sample line from distilled water to sampler and begin analysis
8 Calculations
8 1 Prepare appropriate standard curve derived from processing ammonia standards
through manifold Compute concentration of samples by comparing sample peak heights
with standard curve
9 Precision and Accuracy
»
91 In a single laboratory (EMSL), using surface water samples at concentrations of 1 41,
0 77,0 59 and 0 43 mg NH3-N/1, the standard deviation was ±0 005
9.2 In a single laboratory (EMSL), using surface water samples at concentrations of 0 16 and
1 44 mg NH3-N/1, recoveries were 107% and 99%, respectively
Bibliography
1. Killer, A , and Van Slyke, D , "Determination of Ammonia in Blood", J Biol Chem 102, p
499 (1933)
2, O'Connor, B, Dobbs, R, Vilhers, B , and Dean, R, "Laboratory Distillation of Municipal
Waste Effluents", JWPCF 39, R 25 (1967)
3. Fiore, J., and O'Brien, J E, "Ammonia Determination by Automatic Analysis", Wastes
Engineering 33, p 352 (1962)
4 A wetting agent recommended and supplied by the Techmcon Corporation for use in
AutoAnalyzers
5. ASTM "Manual on Industrial Water and Industrial Waste Water", 2nd Ed , 1966 printing, p
418
6. Booth, R L, and Lobnng, L B , "Evaluation of the AutoAnalyzer II A Progress Report" in
Advances m Automated Analysis 1972 Techmcon International Congress, Vol 8, p 7-10,
Mediad Incorporated, Tarrytown, N Y , (1973)
7 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 616,
Method 604 (1975)
350 1-4
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NITROGEN, AMMONIA
Method 350.2 (Colorimetric; Titrimetric; Potentiometric -
Distillation Procedure)
STORET NO. Total 00610
Dissolved 00608
Scope and Application
1 1 This distillation method covers the determination of ammonia-nitrogen exclusive of total
Kjeldahl nitrogen, in drinking, surface and saline waters, domestic and industrial wastes
It is the method of choice where economics and sample load do not warrant the use of
automated equipment
1 2 The method covers the range from about 0 05 to 1 0 mg NH3-N/1 for the colonmetnc
procedure, from 1 0 to 25 mg/1 for the titnmetric procedure, and from 0 05 to 1400
mg/1 for the electrode method
1 3 This method is described for macro glassware, however, micro distillation equipment
may also be used
Summary of Method
2 1 The sample is buffered at a pH of 9 5 with a borate buffer in order to decrease hydrolysis
of cyanates and organic nitrogen compounds, and is then distilled into a solution of bone
acid The ammonia in the distillate can be determined colonmetncally by nesslenzation,
titnmetncally with standard sulfunc acid with the use of a mixed indicator, or
potentiometncally by the ammonia electrode The choice between the first two
procedures depends on the concentration of the ammonia
Sample Handling and Preservation
3 1 Samples may be preserved with 2 ml of cone H2SO4 per liter and stored at 4°C
Interferences
41 A number of aromatic and aliphatic amines, as well as other compounds, both organic
and inorganic, will cause turbidity upon the addition of Nessler reagent, so direct
nesslenzation (i e , without distillation), has been discarded as an official method
4 2 Cyanate, which may be encountered in certain industrial effluents, will hydrolyze to
some extent even at the pH of 9 5 at which distillation is carried out Volatile alkaline
compounds, such as certain ketones, aldehydes, and alcohols, may cause an off-color
upon nesslenzation in the distillation method Some of these, such as formaldehyde, may
be eliminated by boiling off at a low pH (approximately 2 to 3) prior to distillation and
nesslenzation
4 3 Residual chlorine must also be removed by pretreatment of the sample with sodium
thiosulfate before distillation
Approved for NPDES
Issued 1971
Editorial revision 1974
350 2-1
-------
Apparatus
5.1 An all-glass distilling apparatus with an 800-1000 ml flask
5 2 Spectrophotometer or filter photometer for use at 425 nm and providing a light path of 1
cm or more
5 3 Nessler tubes Matched Nessler tubes (APHA Standard) about 300 mm long, 17 mm
inside diameter, and marked at 225 mm ±15 mm inside measurement from bottom
5.4 Erlenmeyer flasks The distillate is collected m 500 ml glass-stoppered flasks These
flasks should be marked at the 350 and the 500 ml volumes With such marking, it is not
necessary to transfer the distillate to volumetric flasks
Reagents
6 1 Distilled water should be free of ammonia Such water is best prepared by passage
through an ion exchange column containing a strongly acidic cation exchange resin
mixed with a strongly basic amon exchange resin Regeneration of the column should be
earned out according to the manufacturer's instructions
NOTE 1: All solutions must be made with ammonia-free water
6 2 Ammonium chloride, stock solution 1 0 ml = 1 0 mg NH3-N Dissolve 3 819 g NH4C1
m distilled water and bring to volume in a 1 liter volumetric flask
6.3 Ammonium chloride, standard solution 1 0 ml = 0 01 mg Dilute 10 0 ml of stock
solution (6 2) to 1 liter m a volumetric flask
6 4 Boric acid solution (20 g/1) Dissolve 20 g H3BO3 m distilled water and dilute to 1 liter
6 5 Mixed indicator Mix 2 volumes of 02% methyl red in 95% ethyl alcohol with 1 volume
of 02% methylene blue in 95% ethyl alcohol This solution should be prepared fresh
every 30 days
NOTE 2: Specially denatured ethyl alcohol conforming to Formula 3 A or 30 of the U S
Bureau of Internal Revenue may be substituted for 95% ethanol
6 6 Nessler reagent Dissolve 100 g of mercuric iodide and 70 g of potassium iodide in a small
amount of water Add this mixture slowly, with stirring, to a cooled solution of 160 g of
NaOH in 500 ml of water Dilute the mixture to 1 liter If this reagent is stored m a Pyrex
bottle out of direct sunlight, it will remain stable for a period of up to 1 year
NOTE 3: This reagent should give the characteristic color with ammonia within 10
minutes after addition, and should not produce a precipitate with small amounts of
ammonia (0 04 mg in a 50 ml volume)
6 7 Borate buffer Add 88 ml of 0 1 N NaOH solution to 500 ml of 0 025 M sodium
tetraborate solution (5 0 g anhydrous Na2B4O7 or 9 5 g Na2B4O7«10H2O per liter) and
dilute to 1 liter
6 8 Sulfunc acid, standard solution (0 02 N, 1 ml = 0 28 mg NH3-N) Prepare a stock
solution of approximately 0 1 N acid by diluting 3 ml of cone H2SO4 (sp gr 1 84) to 1
liter with CO2-free distilled water Dilute 200 ml of this solution to 1 liter with CO2-free
distilled water
NOTE 4: An alternate and perhaps preferable method is to standardize the
approximately 0 1 N H2SO4 solution against a 0 100 N Na2CO3 solution By proper
dilution the 0 02 N acid can then be prepared
350 2-2
-------
6 8 1 Standardize the approximately 0 02 N acid against 0 0200 N Na2CO3 solution
This last solution is prepared by dissolving 1 060 g anhydrous Na2CO3, oven-dried
at 140°C, and diluting to 1000 ml with CO2-free distilled water
6 9 Sodium hydroxide, 1 N Dissolve 40 g NaOH in ammonia-free water and dilute to 1 liter
6 10 Dechlormating reagents A number of dechlonnatmg reagents may be used to remove
residual chlorine prior to distillation These include
a Sodium thiosulfate (1/70 N) Dissolve 3 5 g Na2S2O3«5H2O in distilled water and
dilute to 1 liter One ml of this solution will remove 1 mg/1 of residual chlorine in
500 ml of sample
b Sodium arsenite (1/70 N) Dissolve 1 0 g NaAsO2 in distilled water and dilute to 1
liter
Procedure
7 1 Preparation of equipment Add 500 ml of distilled water to an 800 ml Kjeldahl flask The
addition of boiling chips which have been previously treated with dilute NaOH will
prevent bumping Steam out the distillation apparatus until the distillate shows no trace
of ammonia with Nessler reagent
7 2 Sample preparation Remove the residual chlorine in the sample by adding
dechlonnatmg agent equivalent to the chlorine residual To 400 ml of sample add 1 N
NaOH (6 9), until the pH is 9 5, checking the pH during addition with a pH meter or by
use of a short range pH paper
7 3 Distillation Transfer the sample, the pH of which has been adjusted to 9 5, to an 800 ml
Kjeldahl flask and add 25 ml of the borate buffer (6 7) Distill 300 ml at the rate of 6-10
ml/mm into 50 ml of 2% boric acid (6 4) contained in a 500 ml Erlenmeyer flask
NOTE 5: The condenser tip or an extension of the condenser tip must extend below the
level of the bone acid solution
Dilute the distillate to 500 ml with distilled water and nesslenze an aliquot to obtain an
approximate value of the ammonia-nitrogen concentration For concentrations above 1
mg/1 the ammonia should be determined titrimetrically For concentrations below this
value it is determined colorimetrically The electrode method may also be used
7 4 Determination of ammonia in distillate Determine the ammonia content of the distillate
titrimetrically, colonmetrically or potentiometrically as described below
741 Titrimetric determination Add 3 drops of the mixed indicator to the distillate and
titrate the ammonia with the 0 02 N H2SO4, matching the end point against a blank
containing the same volume of distilled water and H3BO3 solution
350 2-3
-------
742 Colonmetnc determination Prepare a series of Nessler tube standards as follows
ml of Standard
10 ml = 001 mg NH3-N mg NH3-N/50 0 ml
00 00
05 0 005
10 001
20 002
30 003
40 004
50 005
80 008
100 010
Dilute each tube to 50 ml with distilled water, add 2 0 ml of Nessler reagent (6 6)
and mix After 20 minutes read the absorbance at 425 nm against the blank From
the values obtained plot absorbance vs mg NH3-N for the standard curve
Determine the ammonia in the distillate by nesslenzing 50 ml or an aliquot diluted
to 50 ml and reading the absorbance at 425 nm as described above for the
standards Ammonia-nitrogen content is read from the standard curve
743 Potentiometnc determination Consult the method entitled Nitrogen, Ammonia
Selective Ion Electrode Method (Method 350 3) in this manual
75 It is not imperative that all standards be distilled in the same manner as the samples It is
recommended that at least two standards (a high and low) be distilled and compared to
similar values on the curve to insure that the distillation technique is reliable If distilled
standards do not agree with undistilled standards the operator should find the cause of
the apparent error before proceeding
Calculations
8 1 Titnmetnc
mg/1 NH, - N = Ax 028X1,000
O
where
A = ml 0 02 N H2SO4 used
S = ml sample
8 2 Spectrophotometnc
mg/1 NH3 - N = A xj'000 x .B.
where
A = mg NH3-N read from standard curve
B = ml total distillate collected, including bone acid and dilution
C = ml distillate taken for nesslenzation
D = ml of onginal sample taken
350 2-4
-------
8 3 Potentiometric
mg/1 NH3 - N =
500
D
xA
where
A = mg NHy-N/1 from electrode method standard curve
D = ml of original sample taken
Precision and Accuracy
9 1 Twenty-four analysts in sixteen laboratories analyzed natural water samples containing
exact increments of an ammonium salt, with the following results
Increment as
Nitrogen, Ammonia
mg N/hter
021
026
171
192
Precision as
Standard Deviation
mgN/hter
0122
0070
0244
0279
Accuracy as
Bias,
-554
-18 12
+046
-201
Bias,
mg N/hter
-001
-005
+001
-004
(FWPCA Method Study 2, Nutrient Analyses)
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 410,
Method 41 8 A and 418B (1975)
2 Annual Book of ASTM Standards, Part 31, "Water", Standard D 1426-74, Method A, p 237
(1976)
350 2-5
-------
NITROGEN, AMMONIA
Method 350.3 (Potentiometric, Ion Selective Electrode)
STORET NO. Total 00610
Dissolved 00608
Scope and Application
1 1 This method is applicable to the measurement of ammonia-nitrogen in drinking, surface
and saline waters, domestic and industrial wastes
1 2 This method covers the range from 0 03 to 1400 mg NH3-N/1 Color and turbidity have
no effect on the measurements, thus, distillation may not be necessary
Summary of Method
2 1 The ammonia is determined potentiometncally using an ion selective ammonia electrode
and a pH meter having an expanded millivolt scale or a specific ion meter
2 2 The ammonia electrode uses a hydrophobic gas-permeable membrane to separate the
sample solution from an ammonium chloride internal solution Ammonia in the sample
diffuses through the membrane and alters the pH of the internal solution, which is sensed
by a pH electrode The constant level of chlonde in the internal solution is sensed by a
chloride selective ion electrode which acts as the reference electrode
Sample Handling and Preservation
3 1 Samples may be preserved with 2 ml of cone H2SO4 per liter and stored at 4°C
Interferences
4 1 Volatile amines act as a positive interference
4 2 Mercury interferes by forming a strong complex with ammonia Thus the samples cannot
be preserved with mercuric chlonde
Apparatus
5 1 Electrometer (pH meter) with expanded mV scale or a specific ion meter
5 2 Ammonia selective electrode, such as Orion Model 95-10 or EIL Model 8002-2
5 3 Magnetic stirrer, thermally insulated, and Teflon-coated stirring bar
Reagents
6 1 Distilled water Special precautions must be taken to insure that the distilled water is free
of ammonia This is accomplished by passing distilled water through an ion exchange
column containing a strongly acidic cation exchange resin mixed with a strongly basic
anion exchange resin
6 2 Sodium hydroxide, ION Dissolve 400 g of sodium hydroxide in 800 ml of distilled water
Cool and dilute to 1 liter with distilled water (6 1)
6 3 Ammonium chlonde, stock solution 1 0 ml = 1 0 mg NH3-N Dissolve 3 819 g NH4C1
in water and bnng to volume in a 1 liter volumetric flask using distilled water (6 1)
Issued 1974
Approved for NPDES following preliminary distillation (Method 350 2)
350 3-1
-------
6 4 Ammonium chloride, standard solution 1 0 ml = 0 01 mg NH3-N Dilute 10 0 ml of the
stock solution (6 3) to 1 liter with distilled water (6 1) in a volumetric flask
NOTE 1: When analyzing saline waters, standards must be made up in synthetic ocean
water (SOW), found in Nitrogen, Ammonia Colonmetnc, Automated Phenate Method
(350 1)
7 Procedure
7 1 Preparation of standards Prepare a series of standard solutions covering the
concentration range of the samples by diluting either the stock or standard solutions of
ammonium chloride
72 Calibration of electrometer Place 100 ml of each standard solution in clean 150 ml
beakers Immerse electrode into standard of lowest concentration and add 1 ml of ION
sodium hydroxide solution while mixing Keep electrode in the solution until a stable
reading is obtained
NOTE 2: The pH of the solution after the addition of NaOH must be above 11
Caution Sodium hydroxide must not be added prior to electrode immersion, for
ammonia may be lost from a basic solution
7 3 Repeat this procedure with the remaining standards, going from lowest to highest
concentration Using semiloganthmic graph paper, plot the concentration of ammonia in
mg NH3-N/1 on the log axis vs the electrode potential developed in the standard on the
linear axis, starting with the lowest concentration at the bottom of the scale
7.4 Calibration of a specific ion meter Follow the directions of the manufacturer for the
operation of the instrument
7 5 Sample measurement Follow the procedure in (7 2) for 100 ml of sample in 150 ml
beakers Record the stabilized potential of each unknown sample and convert the
potential reading to the ammonia concentration using the standard curve If a specific
ion meter is used, read the ammonia level directly in mg NH3-N/1
8. Precision and Accuracy
81 In a single laboratory (EMSL), using surface water samples at concentrations of 1 00,
0 77, 0 19, and 0 13 mg NH3-N/1, standard deviations were ±0 038, ±0 017, ±0 007,
and ±0 003, respectively
82 In a single laboratory (EMSL), using surface water samples at concentrations of 0 19 and
0 13 mg NH3-N/1, recoveries were 96% and 91%, respectively
Bibliography
1. Booth, R L , and Thomas, R F, "Selective Electrode Determination of Ammonia in Water
and Wastes", Envir Sci Technology, 7, p 523-526 (1973)
2. Banwart, W L , Bremner, J M, and Tabatabai, M A, "Determination of Ammonium in Soil
Extracts and Water Samples by an Ammonia Electrode", Comm Soil Sci Plant ,3,p 449
(1952)
3. Midgley, D , and Torrance, K , "The Determination of Ammonia in Condensed Steam and
Boiler Feed-Water with a Potentiometnc Ammonia Probe", Analyst, 97 p 626-633 (1972)
350 3-2
-------
NITROGEN, KJELDAHL, TOTAL
Method 351.1 (Colorimetric, Automated Phenate)
STORET NO. 00625
1 Scope and Application
1 1 This automated method may be used to determine Kjeldahl nitrogen in surface and
saline waters The applicable range is 0 05 to 2 0 mg N/l Approximately 20 samples per
hour can be analyzed
2 Summary of Method
2 1 The sample is automatically digested with a sulfunc acid solution containing potassium
sulfate and mercuric sulfate as a catalyst to convert organic nitrogen to ammonium
sulfate The solution is then automatically neutralized with sodium hydroxide solution
and treated with alkaline phenol reagent and sodium hypochlonte reagent This
treatment forms a blue color designated as indophenol Sodium nitroprusside, which
increases the intensity of the color, is added to obtain necessary sensitivity for
measurement of low level nitrogen
3 Definitions
3 1 Total Kjeldahl nitrogen is defined as the sum of free-ammonia and of organic nitrogen
compounds which are converted to (NH4)2SO4 under the conditions of digestion which
are specified below
3 2 Organic Kjeldahl nitrogen is defined as the difference obtained by subtracting the free-
ammonia value from the total Kjeldahl nitrogen value Also, organic Kjeldahl nitrogen
may be determined directly by removal of ammonia before digestion
4 Sample Handling and Preservation
4,1 Samples may be preserved by addition of 2 ml of cone H2SO4 per liter and refrigeration
at 4°C Even when preserved in this manner, conversion of organic nitrogen to ammonia
may occur Therefore, samples should be analyzed as soon as possible
5 Interferences
5 1 Iron and chromium ions tend to catalyze while copper ions tend to inhibit the indophenol
color reaction
6 Apparatus
6 1 Techmcon AutoAnalyzer consisting of
611 Sampler II, equipped with continuous mixer
612 Two proportioning pumps
6 1 3 Manifold I
6 1 4 Manifold II
615 Continuous digester
616 Planetary pump
Approved for NPDES, pending approval for Section 304(h), CWA
Issued 1971
Editorial revision 1974 and 1978
351 1-1
-------
617 Five-gallon Carboy fume-trap
6 1 8 80°C Heating bath
619 Colorimeter equipped with 50 mm tubular flow cell and 630 nm filters
6 1 10 Recorder equipped with range expander
6111 Vacuum pump
7. Reagents
7 1 Distilled water Special precaution must be taken to insure that distilled water is free of
ammonia Such water is prepared by passage of distilled water through an ion exchange
column comprised of a mixture of both strongly acidic cation and strongly basic anion
exchange resins Furthermore, since organic contamination may interfere with this
analysis, use of the resin Dowex XE-75 or equivalent which also tends to remove organic
impurities is advised The regeneration of the ion exchange column should be carried out
according to the instruction of the manufacturer
NOTE 1: All solutions must be made using ammonia-free water
7 2 Sulfunc acid As it readily absorbs ammonia, special precaution must also be taken with
respect to its use Do not store bottles reserved for this determination in areas of potential
ammonia contamination
7 3 EDTA (2% solution) Dissolve 20 g disodium ethylenediamme tetraacetate m 1 liter of
distilled water Adjust pH to 10 5-11 with NaOH (7 4)
7 4 Sodium hydroxide (30% solution) Dissolve 300 g NaOH in 1 liter of distilled water
NOTE 2: The 30% sodium hydroxide should be sufficient to neutralize the digestate In
rare cases it may be necessary to increase the concentration of sodium hydroxide in this
solution to insure neutralization of the digested sample in the manifold at the water
jacketed mixing coil
7 5 Sodium mtroprusside, (0 05% solution) Dissolve 0 5 g Na2Fe(CN)5NO»2H2O in 1 liter
distilled water
7.6 Alkaline phenol reagent Pour 550 ml liquid phenol (88-90%) slowly with mixing into 1
liter of 40% (400 g per liter) NaOH Cool and dilute to 2 liters with distilled water
7 7 Sodium hypochlonte (1% solution) Dilute commercial "Clorox"-200 ml to 1 liter with
distilled water Available chlorine level should be approximately 1% Due to the
instability of this product, storage over an extended period should be avoided
7 8 Digestant mixture Place 2 g red HgO in a 2 liter container Slowly add, with stirring, 300
ml of acid water (100 ml H2SO4 + 200 ml H2O) and stir until cool Add 100 ml 10% (10
g per 100 ml) K2SO4 Dilute to 2 liters with cone sulfunc acid (approximately 500 ml at a
time, allowing time for cooling) Allow 4 hours for the precipitate to settle or filter
through glass fiber filter
7 9 Stock solution Dissolve 4 7193 gof pre-dried (1 hour at 105°C) ammonium sulfate in
distilled water and dilute to 1 0 liter in a volumetric flask 1 0 ml = 10 mg N
7 10 Standard solution Dilute 10 0 ml of stock solution (7 9) to 1000 ml 1 0 ml = 0 01 mg N
711 Using the standard solution (7 10), prepare the following standards in 100 ml volumetric
flasks
351 1-2
-------
Cone mg N/l ml Standard Solution/100 ml
000 00
005 05
010 10
020 20
040 40
060 60
080 80
1 00 10 0
1 50 150
2 00 20 0
Procedure
8 1 Set up manifolds as shown in Figures 1,2, and 3
8 1 1 In the operation of manifold No 1, the control of four key factors is required to
enable manifold No 2 to receive the mandatory representative feed First, the
digestant flowing into the pulse chamber (PC-1) must be bubble free, otherwise, air
will accumulate in A-7, thus altering the ratio of sample to digestant in digester
Second, in maintaining even flow from the digestor helix, the peristaltic pump must
be adjusted to cope with differences in density of the digestate and the wash water
Third, the sample pick-up rate from the helix must be precisely adjusted to insure
that the entire sample is aspirated into the mixing chamber And finally, the
contents of the "Mixing Chamber" must be kept homogeneous by the proper
adjustment of the air bubbling rate
8 1 2 In the operation of manifold No 2, it is important m the neutralization of the
digested sample to adjust the concentration of the NaOH so that the waste from the
C-3 debubbler is slightly acid to Hydnon B paper
8 1 3 The digestor temperature is 390°C for the first stage and 360°C for the second and
third stages
8 2 Allow both colorimeter and recorder to warm up for 30 minutes Run a baseline with all
reagents, feeding distilled water through the sample line Adjust dark current and
operative opening on colorimeter to obtain stable baseline
8 3 Set sampling rate of Sampler II at 20 samples per hour, using a sample to wash ratio of 1
to 2 (1 minute sample, 2 minute wash)
8 4 Arrange various standards in sampler cups in order of increasing concentration
Complete loading of sampler tray with unknown samples
8 5 Switch sample line from distilled water to sampler and begin analysis
Calculation
9 1 Prepare standard curve by plotting peak heights of processed standards against
concentration values Compute concentration of samples by comparing sample peak
heights with standard curve
9 2 Any sample that has a computed concentration that is less than 10% of the sample run
immediately prior to it must be rerun
351 1-3
-------
10
1.
Precision and Accuracy
10 1 Six laboratories analyzed four natural water samples containing exact increments of
organic nitrogen compounds, with the following results
Increment as
Kjeldahl-Nitrogen
mg N/liter
1 89
2 18
509
581
Precision as
Standard Deviation
Kjeldahl-N mgN/hter
054
061
125
185
Bias,
-246
-283
-238
-219
Accuracy as
Bias,
mg N/hter
-046
-062
-121
-127
Bibliography
Kammerer, P A , Rodel, M G, Hughes, R A , and Lee, G F , "Low Level Kjeldahl Nitrogen
Determination on the Techmcon Auto Analyzer" Environmental Science and Technology, 1,
340(1967) -
McDamel, W H , Hemphill, R N, Donaldson, W T, "Automatic Determination of Total
Kjeldahl Nitrogen in Estuanne Waters" Presented at Techmcon Symposium on Automation
m Analytical Chemistry, New York, October 3,1967
B O'Connor, Dobbs, Vilhers, and Dean, "Laboratory Distillation of Municipal Waste
Effluents" JWPCF39.R25,1967
351 1-4
-------
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351 1-7
-------
NITROGEN, KJELDAHL, TOTAL
Method 351.2 (Colorimetric, Semi-Automated Block Digester, AAII)
STORET NO. 00625
1 Scope and Application
1 1 This method covers the determination of total Kjeldahl nitrogen in drinking and surface
waters, domestic and industrial wastes The procedure converts nitrogen components of
biological origin such as ammo acids, proteins and peptides to ammonia, but may not
convert the mtrogeneous compounds of some industrial wastes such as amines, mtro
compounds, hydrazones, oximes, semicarbazones and some refractory tertiary amines
The applicable range of this method is 0 1 to 20 mg/1 TKN The range may be extended
with sample dilution
2 Summary of Method
2 1 The sample is heated in the presence of sulfunc acid, K2SO4 and HgSO4 for two and one
half hours The residue is cooled, diluted to 25 ml and placed on the AutoAnalyzer for
ammonia determination This digested sample may also be used for phosphorus
determination
3 Definitions
3 1 Total Kjeldahl nitrogen is defined as the sum of free-ammonia and organic nitrogen
compounds which are converted to ammonium sulfate (NH4)2SO4, under the conditions
of digestion described below
3 2 Organic Kjeldahl nitrogen is defined as the difference obtained by subtracting the free-
ammonia value (Method 350 2, Nitrogen, Ammonia, this manual) from the total
Kjeldahl nitrogen value
4 Sample Handling and Preservation
4 1 Samples may be preserved by addition of 2 ml of cone H2SO4 per liter and stored at 4°C
Even when preserved in this manner, conversion of organic nitrogen to ammonia may
occur Therefore, samples should be analyzed as soon as possible
5 Apparatus
5 1 Block Digestor-40
5 2 Techmcon Manifold for Ammonia (Figure 1)
5 3 Chemware TFE (Teflon boiling stones), Markson Science, Inc, Box 767, Delmar, CA
92014)
6 Reagents
6 1 Mercuric Sulfate Dissolve 8 g red mercuric oxide (HgO) in 50 ml of 1 4 sulfunc acid (10
ml cone H2SO4 40 ml distilled water) and dilute to 100 ml with distilled water
6 2 Digestion Solution (Sulfunc acid-mercunc sulfate-potassium sulfate solution) Dissolve
133 g of K2SO4 in 700 ml of distilled water and 200 ml of cone H2SO4 Add 25 ml of
mercunc sulfate solution and dilute to 1 liter
Pending approval for NPDES
Issued 1978
351 2-1
-------
6.3 Sulfunc Acid Solution (4%) Add 40 ml of cone sulfunc acid to 800 ml of ammonia free
distilled water, cool and dilute to 1 liter
6 4 Stock Sodium Hydroxide (20%) Dissolve 200 g of sodium hydroxide in 900 ml of
ammonia-free distilled water and dilute to 1 liter
6 5 Stock Sodium Potassium Tartrate Solution (20%) Dissolve 200 g sodium potassium
tartrate in about 800 ml of ammonia-free distilled water and dilute to 1 liter
6 6 Stock Buffer Solution Dissolve 134 0 g of sodium phosphate, dibasic (Na2HPO4) in
about 800 ml of ammonia free water Add 20 g of sodium hydroxide and dilute to 1 liter
6.7 Working Buffer Solution Combine the reagents in the stated order, add 250 ml of stock
sodium potassium tartrate solution (6 5) to 200 ml of stock buffer solution (6 6) and mix
Add xx ml sodium hydroxide solution (6 4) and dilute to 1 liter See concentration
ranges, Table I, for composition of working buffer
6.8 Sodium Sahcylate/Sodium Nitroprusside Solution Dissolve 150 g of sodium sahcylate
and 0 3 g of sodium nitroprusside in about 600 ml of ammonia free water and dilute to 1
liter.
6 9 Sodium Hypochlonte Solution Dilute 6 0 ml sodium hypochlonte solution (clorox) to
100 ml with ammonia free distilled water
6 10 Ammonium chloride, stock solution Dissolve 3 819 g NH4C1 m distilled water and bring
to volume in a 1 liter volumetric flask 1 ml= 1 0 mg NH3-N
7. Procedure
Digestion
71 To 20 or 25 ml of sample, add 5 ml of digestion solution (6 2) and mix (use a vortex
mixer)
7 2 Add (4-8) Teflon boiling stones (5 3) Too many boiling chips will cause the sample to
boil over
7 3 With Block Digester in manual mode set low and high temperature at 160°C and preheat
unit to 160°C Place tubes in digester and switch to automatic mode Set low temperature
tuner for 1 hour Reset high temperature to 380°C and set timer for 21/2 hours
7 4 Cool sample and dilute to 25 ml with ammonia free water
Colonmetnc Analysis
7.5 Check the level of all reagent containers to ensure an adequate supply
7 6 Excluding the salicylate line, place all reagent lines in their respective containers, connect
the sample probe to the Sampler IV and start the proportioning pump
7 7 Flush the Sampler IV wash receptacle with about 25 ml of 4 0% sulfuric acid (6 3)
7 8 When reagents have been pumping for at least five minutes, place the sahcylate line in its
respective container and allow the system to equilibrate If a precipitate forms after the
addition of sahcylate, the pH is too low Immediately stop the proportioning pump and
flush the coils with water using a syringe Before restarting the system, check the
concentration of the sulfunc acid solutions and/or the working buffer solution
351 2-2
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79 To prevent precipitation of sodium sahcylate in the waste tray, which can clog the tray
outlet, keep the nitrogen fiowcell pump tube and the nitrogen Colorimeter "To Waste"
tube separate from all other lines or keep tap water flowing in the waste tray
7 10 After a stable baseline has been obtained start the Sampler
8 Calculations
8 1 Prepare standard curve by plotting peak heights of processed standards against
concentration values Compute concentrations by comparing sample peak heights with
standard curve
9 Precision and Accuracy
91 In a single laboratory (EMSL), using sewage samples of concentrations of 1 2, 2 6, and
1 7 mg N/l, the precision was ±0 07, ±0 03 and ±0 15, respectively
9.2 In a single laboratory (EMSL), using sewage samples of concentrations of 4 7 and 8 74
mg N/l, the recoveries were 99 and 99%, respectively
i ' i * j '
i „ * »i «
Bibliography
1 McDamel, W H, Hemphill, R N and Donaldson, W T, "Automatic Determination of Total
Kjeldahl Nitrogen in Estuarme Water", Techmcon Symposia, pp 362-367, Vol 1,1967
2 Gales, M E , and Booth, R L, "Evaluation of Organic Nitrogen Methods", EPA Office of
Research and Monitoring, June, 1972
3 Gales, ME and Booth, RL, "Simultaneous and Automated Determination of Total
Phosphorus and Total Kjeldahl Nitrogen", Methods Development and Quality Assurance
Research Laboratory, May, 1974
4. Techmcon "Total Kjeldahl Nitrogen and Total Phosphorus BD-40 Digestion Procedure for
Water", August, 1974
5 Gales, ME, and Booth, RL, "Evaluation of the Block Digestion System for the
Measurement of Total Kjeldahl Nitrogen and Total Phosphorus", EPA-600/4-78-015,
Environmental Monitoring and Support Laboratory, Cinncmnati, Ohio
351 2-4
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-------
NITROGEN, KJELDAHL, TOTAL
Method 351.3 (Colorimetric; Titrimetric; Potentiometric)
STORET NO. 00625
1 Scope and Application
1 1 This method covers the determination of total Kjeldahl nitrogen in drinking, surface and
saline waters, domestic and industrial wastes The procedure converts nitrogen
components of biological origin such as ammo acids, proteins and peptides to ammonia,
but may not convert the nitrogenous compounds of some industrial wastes such as
amines, mtro compounds, hydrazones, oximes, semicarbazones and some refractory
tertiary amines
1 2 Three alternatives are listed for the determination of ammonia after distillation the
titrimetnc method which is applicable to concentrations above 1 mg N/liter, the
Nesslenzation method which is applicable to concentrations below 1 mg N/liter, and the
potentiometnc method applicable to the range 0 05 to 1400 mg/1
1 3 This method is described for macro and micro glassware systems
2 Definitions
2 1 Total Kjeldahl nitrogen is defined as the sum of free-ammonia and organic nitrogen
compounds which are converted to ammonium sulfate (NH4)2SO4, under the conditions
of digestion described below
2 2 Organic Kjeldahl nitrogen is defined as the difference obtained by subtracting the free-
ammonia value (Method 350 2, Nitrogen, Ammonia, this manual) from the total
Kjeldahl nitrogen value This may be determined directly by removal of ammonia before
digestion
3 Summary of Method
3 1 The sample is heated in the presence of cone sulfunc acid, K2SO4 and HgSO4 and
evaporated until SO3 fumes are obtained and the solution becomes colorless or pale
yellow The residue is cooled, diluted, and is treated and made alkaline with a hydroxide-
thiosulfate solution The ammonia is distilled and determined after distillation by
Nesslenzation, titration or potentiometry
4 Sample Handling and Preservation
4 1 Samples may be preserved by addition of 2 ml of cone H2SO4 per liter and stored at 4°C
Even when preserved in this manner, conversion of organic nitrogen to ammonia may
occur Preserved samples should be analyzed as soon as possible
5 Interference
5 1 High nitrate concentrations (10X or more than the TKN level) result m low TKN
values The reaction between nitrate and ammonia can be prevented by the use of an
anion exchange resin (chloride form) to remove the nitrate prior to the TKN analysis
Approved for NPDES
Issued 1971
Editorial revision 1974 and 1978
351 3-1
-------
6. Apparatus
6.1 Digestion apparatus A Kjeldahl digestion apparatus with 800 or 100 ml flasks and
suction takeoff to remove SO3 fumes and water
6 2 Distillation apparatus The macro Kjeldahl flask is connected to a condenser and an
adaptor so that the distillate can be collected Micro Kjeldahl steam distillation
apparatus is commercially available
6 3 Spectrophotometer for use at 400 to 425 nm with a light path of 1 cm or longer
7 Reagents
7.1 Distilled water should be free of ammonia Such water is best prepared by the passage of
distilled water through an ion exchange column containing a strongly acidic cation
exchange resin mixed with a strongly basic anion exchange resin Regeneration of the
column should be earned out according to the manufacturer's instructions
NOTE 1: All solutions must be made with ammonia-free water
7 2 Mercuric sulfate solution Dissolve 8 g red mercuric oxide (HgO) in 50 ml of 1 4 sulfunc
acid (10 0 ml cone H2SO4 40 ml distilled water) and dilute to 100 ml with distilled
water
7 3 Sulfunc acid-mercuric sulfate-potassium sulfate solution Dissolve 267 g K2SO4 in 1300
ml distilled water and 400 ml cone H2SO4 Add 50 ml mercunc sulfate solution (7 2) and
dilute to 2 liters with distilled water
74 Sodium hydroxide-sodium thiosulfate solution Dissolve 500 g NaOH and 25 g
Na2S2O3»5H2O in distilled water and dilute to 1 liter
7 5 Mixed indicator Mix 2 volumes of 0 2% methyl red in 95% ethanol with 1 volume of
0 2% methylene blue in ethanol Prepare fresh every 30 days
7 6 Bone acid solution Dissolve 20 g bone acid, H3BO3, in water and dilute to 1 liter with
distilled water
7 7 Sulfunc acid, standard solution (0 02 N) 1 ml = 0 28 mg NH3-N Prepare a stock
solution of approximately 0 1 N acid by diluting 3 ml of cone H2SO4 (sp gr 1 84) to 1
liter with CO2-free distilled water Dilute 200 ml of this solution to 1 liter with CO2-free
distilled water Standardize the approximately 0 02 N acid so prepared against 0 0200 N
Na2CO3 solution This last solution is prepared by dissolving 1 060 g anhydrous Na2CO3,
oven-dried at 140°C, and diluting to 1 liter with CO2-free distilled water
NOTE 2: An alternate and perhaps preferable method is to standardize the
approximately 0 1 N H2SO4 solution against a 0 100 N Na2CO3 solution By proper
dilution the 0 02 N acid can the be prepared
7.8 Ammonium chlonde, stock solution 1 0 ml = 1 0 mg NH3-N Dissolve 3 819 g NH4C1
m water and make up to 1 liter in a volumetric flask with distilled water
7 9 Ammonium chlonde, standard solution 1 0 ml = 0 01 mg NH3-N Dilute 10 0 ml of the
stock solution (7 8) with distilled water to 1 liter in a volumetric flask
7 10 Nessler reagent Dissolve 100 g of mercuric iodide and 70 g potassium iodide in a small
volume of distilled water Add this mixture slowly, with stirring, to a cooled solution of
160 g of NaOH m 500 ml of distilled water Dilute the mixture to 1 liter The solution is
stable for at least one year if stored m a pyrex bottle out of direct sunlight
351 3-2
-------
NOTE 3. Reagents 7 7, 7 8, 7 9, and 7 10 are identical to reagents 6 8, 6 2, 6 3, and 6 6
described under Nitrogen, Ammonia (Colonmetric, Titrimetnc, Potentiometnc-
Distillation Procedure, Method 350 2)
Procedure
8 1 The distillation apparatus should be pre-steamed before use by distilling all mixture of
distilled water and sodium hydroxide-sodium thiosulfate solution (7 4) until the distillate
is ammonia-free This operation should be repeated each time the apparatus is out of
service long enough to accumulate ammonia (usually 4 hours or more)
8 2 Macro Kjeldahl system
821 Place a measured sample or the residue from the distillation in the ammonia
determination (for Organic Kjeldahl only) into an 800 ml Kjeldahl flask The
sample size can be determined from the following table
Kjeldahl Nitrogen Sample Size
in Sample, mg/1 ml
0-5 500
5-10 250
10-20 100
20-50 50 0
50-500 25 0
Dilute the sample, if required, to 500 ml with distilled water, and add 100 ml
sulfunc acid-mercuric sulfate-potassmm sulfate solution (7 3) Evaporate the
mixture in the Kjeldahl apparatus until SO3 fumes are given off and the solution
turns colorless or pale yellow Continue heating for 30 additional minutes Cool the
residue and add 300 ml distilled water
822 Make the digestate alkaline by careful addition of 100 ml of sodium hydroxide -
thiosulfate solution (7 4) without mixing
NOTE 5- Slow addition of the heavy caustic solution down the tilted neck of the
digestion flask will cause heavier solution to underlay the aqueous sulfunc acid
solution without loss of free-ammonia Do not mix until the digestion flask has
been connected to the distillation apparatus
823 Connect the Kjeldahl flask to the condenser with the tip of condenser or an
extension of the condenser tip below the level of the boric acid solution (7 6) in the
receiving flask
824 Distill 300 ml at the rate of 6-10 ml/mm, into 50 ml of 2% bone acid (7 6)
contained in a 500 ml Erlenmeyer flask
825 Dilute the distillate to 500 ml in the flask These flasks should be marked at the 350
and the 500 ml volumes With such marking, it is not necessary to transfer the
distillate to volumetric flasks For concentrations above 1 mg/1, the ammonia can
be determined titnmetncally For concentrations below this value, it is determined
colonmetncally The potentiometnc method is applicable to the range 0 05 to 1400
mg/1
351 3-3
-------
8.3 Micro Kjeldahl system
8.3 1 Place 50 0 ml of sample or an aliquot diluted to 50 ml m a 100 ml Kjeldahl flask
and add 10 ml sulfunc acid-mercuric sulfate-potassium sulfate solution (7 3)
Evaporate the mixture in the Kjeldahl apparatus until SO3 fumes are given off and
the solution turns colorless or pale yellow Then digest for an additional 30
minutes Cool the residue and add 30 ml distilled water
832 Make the digestate alkaline by careful addition of 10 ml of sodium hydroxide-
thiosulfate solution (7 4) without mixing Do not mix until the digestion flask has
been connected to the distillation apparatus
833 Connect the Kjeldahl flask to the condenser with the tip of condenser or an
extension of the condenser tip below the level of the bone acid solution (7 6) in the
receiving flask or 50 ml short-form Nessler tube
8.3 4 Steam distill 30 ml at the rate of 6-10 ml/mm , into 5 ml of 2% boric acid (7 6)
835 Dilute the distillate to 50 ml For concentrations above 1 mg/1 the ammonia can be
determined titnmetncally For concentrations below this value, it is determined
colonmetncally The potentiometnc method is applicable to the range 0 05 to 1400
mg/1
8.4 Determination of ammonia in distillate Determine the ammonia content of the distillate
titnmetncally, colonmetncally, or potentiometncally, as descnbed below
841 Titnmetnc determination Add 3 drops of the mixed indicator (7 5) to the distillate
and titrate the ammonia with the 0 02 N H2SO4 (7 7), matching the endpomt
against a blank containing the same volume of distilled water and H3BO3 (7 6)
solution
842 Colonmetnc determination Prepare a senes of Nessler tube standards as follows
ml of Standard
1 0 ml = 0 01 mg NH3-N mg NH3-N/50 0 ml
00 00
05 0 005
10 0010
20 0 020
40 0 040
50 0 050
80 0 080
100 010
Dilute each tube to 50 ml with ammonia free water, add 1 ml of Nessler Reagent
(7 10) and mix After 20 minutes read the absorbance at 425 nm against the blank
From the values obtained for the standards plot absorbance vs mg NH3-N for the
standard curve Develop color in the 50 ml diluted distillate in exactly the same
manner and read mg NH3-N from the standard curve
8 4.3 Potentiometnc determination Consult the method entitled Nitrogen, Ammonia
Potentiometnc, Ion Selective Electrode Method, (Method 350 3) in this manual
844 It is not imperative that all standards be treated in the same manner as the samples
It is recommended that at least 2 standards (a high and low) be digested, distilled,
351 3-4
-------
and compared to similar values on the curve to insure that the digestion-distillation
technique is reliable If treated standards do not agree with untreated standards the
operator should find the cause of the apparent error before proceeding
Calculation
9 1 If the titnmetnc procedure is used, calculate Total Kjeldahl Nitrogen, in mg/1, m the
original sample as follows
TKN,mg/l= (A - B)N x F x 1,000
S
where
A = milhliters of standard 0 020 N H2SO4 solution used in titrating sample
B = milhliters of standard 0 020 N H2SO4 solution used m titrating blank
N = normality of sulfunc acid solution
F = milliequivalent weight of nitrogen (14 mg)
S = milhliters of sample digested
If the sulfunc acid is exactly 0 02 N the formula is shortened to
TKN, mg/1 = x 28°
92 If the Nessler procedure is used, calculate the Total Kjeldahl Nitrogen, m mg/1, in the
original sample as follows
TKN, mg/1 = A Xp' x -.
where
A = mg NH3-N read from curve
B = ml total distillate collected including the H3BO3
C = ml distillate taken for Nesslenzation
D = ml of original sample taken
9 3 Calculate Organic Kjeldahl Nitrogen in mg/1, as follows
Organic Kjeldahl Nitrogen = TKN -(NH3-N )
351 3-5
-------
9 4 Potentiometric determination Calculate Total Kjeldahl Nitrogen, in mg/1, in the
original sample as follows
TKN, mg/1 = -jj x A
where
A = mg NH3-N/1 from electrode method standard curve
B = volume of diluted distillate in ml
D = ml of original sample taken
10. Precision
10 1 Thirty-one analysts in twenty laboratories analyzed natural water samples containing
exact increments of organic nitrogen, with the following results
Increment as
Nitrogen, Kjeldahl
mg N/liter
020
031
410
461
Precision as
Standard Deviation
mg N/liter
0197
0247
1056
1 191
Accuracy as
Bias,
+ 1554
+ 545
+ 103
- 167
Bias,
mg N/liter
+003
+002
+004
-008
(FWPCA Method Study 2, Nutrient Analyses)
Bibliography
1. Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 437,
Method 421 (1975)
2. Schlueter, Albert, "Nitrate Interference In Total Kjeldahl Nitrogen Determinations and Its
Removal by Amon Exchange Resins", EPA Report 600/7-77-017
351 3-6
-------
NITROGEN, KJELDAHL, TOTAL
Method 351.4 (Potentiometric, Ion Selective Electrode)
STORET NO. 00625
1 Scope and Application
1 1 This method is applicable to the measurement of TKN in drinking and surface water,
domestic and industrial wastes
1 2 This method covers the range from 0 03 to 25 mg TKN/1
2 Summary of Method
2 1 Following digestion and cooling, distilled water is added to the digestion flask and the
pH adjusted to between 3 and 4 5 by the addition of 10 N NaOH The sample is cooled
and transferred to a 100 ml beaker After inserting the electrode into the sample, NaOH-
Nal-EDTA is added and the ammonia measured (Ethylene diamine tetraacetic acid
(EDTA) is added to the alkaline reagent (NaOH-Nal) to prevent precipitation of
hydroxides, thereby avoiding deposition on the electrode membrane)
3 Sample Handling and Preservation
3 1 Samples may be preserved by addition of 2 ml of cone H2SO4 per liter and stored at 4°C
Even when preserved in this manner, conversion of organic nitrogen to ammonia may
occur Preserved samples should be analyzed as soon as possible
4 Interferences
4 1 Interference from metals is eliminated with the addition of Nal
4 2 High nitrate concentrations (10X or more than the TKN level) result in low TKN
values The reaction between nitrate and ammonia can be prevented by the use of an
anion exchange resin (chloride form) to remove the nitrate prior to the TKN analysis
5 Apparatus
5 1 Electrometer (pH meter) with expanded mV scale
5 2 Ammonia selective electrode, such as Orion Model 95-10
5 3 Magnetic stirrer, thermally insulated and Teflon-coated stirring bar
5 4 Digestion apparatus A Kjeldahl digestion apparatus with 800 or 100 ml flasks and
suction take off to remove SO3 fumes and water
5 5 Techmcon Block Digester BD-40
6 Reagents
6 1 Distilled water should be free of ammonia Such water is best prepared by passing
distilled water through an ion exchange column containing a strongly acidic cation
exchange resin mixed with a strongly basic anion exchange resin Regeneration of the
column should be carried out according to the manufacturer's instructions
NOTE 1: All solutions must be made with ammonia-free water
6 2 Mercuric sulfate solution Dissolve 8 g red mercuric oxide (HgO) in 50 ml of 1 4 sulfunc
acid (10 0 ml cone H2SO4 40 ml distilled water) and dilute to 100 ml with distilled water
Pending approval for NPDES
Issued 1978
351 4-1
-------
6 3 Sulfunc acid-mercuric sulfate-potassium sulfate solution Dissolve 267 g K2SO4 in 1300
ml distilled water and 400 ml cone H2SO4 Add 50 ml mercuric sulfate solution (6 2) and
dilute to 2 liters with distilled water
6.4 Sodium hydroxide ION Dissolve 400 g NaOH in 600 ml of ammonia-free water, cool
and dilute to 1 liter
6.5 Sodium Hydroxide, Sodium Iodide and EDTA Solution Dissolve 400 g of NaOH, 300 g
Nal and 2 g of EDTA m 700 ml of ammonia-free water, cool and dilute to 1 liter
6 6 Ammonium chloride, stock solution 1 0 ml = 1 0 mg NH3-N Dissolve 3 819 g NH4C1
m water and make up to 1 liter m a volumetric flask with distilled water
6.7 Ammonium chloride, standard solution 1 0 ml = 0 01 mg NH3-N Dilute 10 0 ml of the
stock solution (6 6) to 1 liter with distilled water m a volumetric flask
Procedure
7.1 Macro Kjeldahl system
7 7.1 Place a measured sample or the residue from the distillation in the ammonia
determination (for Organic Kjeldahl only) into an 800 ml Kjeldahl flask The
sample size can be determined from the following table
Kjedahl Nitrogen Sample Size
m Sample, mg/1 ml
0-5 500
5-10 250
10-20 100
20-50 50 0
50-500 25 0
Dilute the sample, if required, to 500 ml with distilled water, and add 100 ml
sulfunc acid-mercuric sulfate-potassium sulfate solution (6 3) and evaporate the
mixture m the Kjeldahl apparatus until SO3 fumes are given off and the solution
turns colorless or pale yellow Continue heating for 30 additional minutes Cool the
residue and add 500 ml distilled water and mix
7 2 Micro Kjeldahl system
721 Place 50 0 ml of sample, or an aliquot diluted to 50 ml, in a 100 ml Kjeldahl flask
and add 10 ml sulfunc acid-mercuric sulfate-potassium sulfate solution (6 3)
Evaporate the mixture in the Kjeldahl apparatus until SO3 fumes are given off and
the solution turns colorless or pale yellow Then digest for an additional 30
minutes Cool the residue, add 44 ml distilled water and mix
7 3 Block Digester
731 Place 20 ml of sample, or an aliquot diluted to 20 ml, in the digestion tube Add 5
ml of sulfunc acid-mercuric sulfate-potassium sulfate solution (6 3) and mix Add
4-8 Teflon boiling stones
732 Place tubes in digestor that has been preheated to 200°C
7 3 3 Set low temperature at 200°C for 1 hour, the high temperature at 380°C and total
time for two and one half hours
3514-2
-------
734 After the temperature of the block has reached 380°C, the time should be set for 30
minutes Longer time and higher temperature may result in complete loss of the
acid
735 Cool, add 25 ml of ammonia-free water and mix
7 4 Electrode analysis
741 All standards should be treated as the samples and should contain the same
concentration of sulfuric acid-mercuric sulfate-potassium sulfate solution (6 3)
742 Macro Kjeldahl system
To a 100 ml aliquot, add 15 ml of 10 N NaOH (6 4), mix and cool to room
temperature Immerse the electrode in the sample solution and add 4 ml of NaOH-
Nal-EDTA reagent (6 5) while mixing Allow the electrode to remain immersed in
the solution until a stable reading is obtained
743 Micro Kjeldahl system
Add 6 ml of 10 N NaOH solution (6 4), cool to room temperature and transfer the
sample to a 100 ml beaker Immerse the electrode m the sample solution and add 4
ml of NaOH-Nal-EDTA reagent (6 5) while mixing Allow the electrode to remain
immersed in the solution until a stable reading is obtained
744 Block Digestor
Add 3 ml of 10 N NaOH (6 4), cool to room temperature, dilute to 50 ml and
transfer to a 100 ml beaker Immerse the electrode in the sample and add 2 ml of
NaOH-Nal-EDTA reagent (6 5) while mixing Allow the electrode to remain
immersed in the solution until a stable reading is obtained
Calculation
Using semiloganthmic graph paper, plot the concentration of ammonia in mg NH3-N on the
log axis vs the electrode potential developed in the standard on the linear axis, starting with the
lowest concentration at the bottom of the scale
mgTKN/l = (A - B)x 1.000
where
A = mg NH3-N read from standard curve
B = mg NH3-N in blank
C = ml of original sample taken
Precision and Accuracy
9 1 Precision and accuracy data are not available at this time
Bibliography
Schlueter, A, "Nitrate Interference in Total Kjeldahl Nitrogen Determinations and its
Removal by Amon Exchange Resin", EPA-600/7-77-017
3514-3
-------
NITROGEN, NITRATE
Method 352.1 (Colorimetric, Brucine)
STORET NO. Total 00620
1 Scope and Application
1 1 This method is applicable to the analysis of drinking, surface and saline waters, domestic
and industrial wastes Modification can be made to remove or correct for turbidity, color,
salinity, or dissolved organic compounds in the sample
1 2 The applicable range of concentrations is 0 1 to 2 mg NO3-N/hter
2 Summary of Method
2 1 This method is based upon the reaction of the nitrate ion with brucine sulfate in a 13 N
H2SO4 solution at a temperature of 100°C The color of the resulting complex is measured
at 410 nm Temperature control of the color reaction is extremely critical
3 Sample Handling and Preservation
3 1 Analysis should be made as soon as possible If analysis can be made within 24 hours, the
sample should be preserved by refrigeration at 4°C When samples must be stored for
more than 24 hours, they should be preserved with sulfunc acid (2 ml cone H2SO4 per
liter) and refrigeration
4 Interferences
4 1 Dissolved organic matter will cause an off color in 13 N H2SO4 and must be compensated
for by additions of all reagents except the brucme-sulfamlic acid reagent This also
applies to natural color present not due to dissolved organics
42 The effect of salinity is eliminated by addition of sodium chloride to the blanks, standards
and samples
4 3 All strong oxidizing or reducing agents interfere The presence of oxidizing agents may
be determined with a total residual chlorine test kit
44 Residual chlorine interference is eliminated by the addition of sodium arsemte
4 5 Ferrous and ferric iron and quadrivalent manganese give slight positive interferences, but
in concentrations less than 1 mg/1 these are negligible
4 6 Uneven heating of the samples and standards during the reaction time will result in
erratic values The necessity for absolute control of temperature during the critical color
development period cannot be too strongly emphasized
5 Apparatus
5 1 Spectrophotometer or filter photometer suitable for measuring absorbance at 410 nm
5 2 Sufficient number of 40-50 ml glass sample tubes for reagent blanks, standards and
samples
5 3 Neoprene coated wire racks to hold sample tubes
5 4 Water bath suitable for use at 100°C This bath should contain a stirring mechanism so
that all tubes are at the same temperature and should be of sufficient capacity to accept
Approved for NPDES and SDWA
Issued 1971
352 1-1
-------
the required number of tubes without significant drop in temperature when the tubes are
immersed
5 5 Water bath suitable for use at 10-15°C
Reagents
6 1 Distilled water free of nitrite and nitrate is to be used in preparation of all reagents and
standards
6 2 Sodium chloride solution (30%) Dissolve 300 g NaCl in distilled water and dilute to 1
liter
6 3 Sulfunc acid solution Carefully add 500 ml cone H2SO4 to 125 ml distilled water Cool
and keep tightly stoppered to prevent absorption of atmospheric moisture
64 Brucme-sulfanilic acid reagent Dissolve 1 g brucine sulfate
[(C23H26N2O4)2«H2SO4«7H2O] and 0 1 g sulfamhc acid (NH2C6H4SO3H«H2O) in 70 ml
hot distilled water Add 3 ml cone HC1, cool, mix and dilute to 100 ml with distilled
water Store in a dark bottle at 5°C This solution is stable for several months, the pink
color that develops slowly does not effect its usefulness Mark bottle with warning
CAUTION Brucine Sulfate is toxic, take care to avoid ingestion
6 5 Potassium nitrate stock solution 1 0 ml = 0 1 mg NO3-N Dissolve 0 7218 g anhydrous
potassium nitrate (KNO3) in distilled water and dilute to 1 liter in a volumetric flask
Preserve with 2 ml chloroform per liter This solution is stable for at least 6 months
6 6 Potassium nitrate standard solution 1 0 ml = 0 001 mg NO3-N Dilute 10 0 ml of the
stock solution (6 5) to 1 liter in a volumetric flask This standard solution should be
prepared fresh weekly
6 7 Acetic acid (1 + 3) Dilute 1 volume glacial acetic acid (CH3COOH) with 3 volumes of
distilled water
6 8 Sodium hydroxide (IN) Dissolve 40 g of NaOH in distilled water Cool and dilute to 1
liter
Procedure
7.1 Adjust the pH of the samples to approximately 7 with acetic acid (6 7) or sodium
hydroxide (6 8) If necessary, filter to remove turbidity
7 2 Set up the required number of sample tubes in the rack to handle reagent blank,
standards and samples Space tubes evenly throughout the rack to allow for even flow of
bath water between the tubes This should assist in achieving uniform heating of all
tubes
73 If it is necessary to correct for color or dissolved organic matter which will cause color on
heating, a set of duplicate samples must be run to which all reagents except the brucme-
sulfamhc acid have been added
7 4 Pipette 10 0 ml of standards and samples or an aliquot of the samples diluted to 10 0 ml
into the sample tubes
75 If the samples are saline, add 2 ml of the 30% sodium chloride solution (6 2) to the
reagent blank, standards and samples For fresh water samples, sodium chloride solution
may be omitted Mix contents of tubes by swirling and place rack in cold water bath
(0-10°C)
352 1-2
-------
7 6 Pipette 10 0 ml of sulfunc acid solution (6 3) into each tube and mix by swirling Allow
tubes to come to thermal equilibrium in the cold bath Be sure that temperatures have
equilibrated in all tubes before continuing
7 7 Add 0 5 ml brucine-sulfamhc acid reagent (6 4) to each tube (except the interference
control tubes, 7 3) and carefully mix by swirling, then place the rack of tubes in the 100°C
water bath for exactly 25 minutes
Caution Immersion of the tube rack into the bath should not decrease the temperature of
the bath more than 1 to 2°C In order to keep this temperature decrease to an absolute
minimum, flow of bath water between the tubes should not be restricted by crowding too
many tubes into the rack If color development in the standards reveals discrepancies in
the procedure, the operator should repeat the procedure after reviewing the temperature
control steps
7 8 Remove rack of tubes from the hot water bath and immerse in the cold water bath and
allow to reach thermal equilibrium (20-25°C)
7 9 Read absorbance against the reagent blank at 410 nm using a 1 cm or longer cell
Calculation
8 1 Obtain a standard curve by plotting the absorbance of standards run by the above
procedure against mg NO3-N/1 (The color reaction does not always follow Beer's law)
8 2 Subtract the absorbance of the sample without the brucine-sulfamhc reagent from the
absorbance of the sample containing brucme-sulfamlic acid and determine mg
NO3-N/1 Multiply by an appropriate dilution factor if less than 10 ml of sample is
taken
Precision and Accuracy
9 1 Twenty-seven analysts in fifteen laboratories analyzed natural water samples containing
exact increments of inorganic nitrate, with the following results
Increment as
Nitrogen, Nitrate
mg N/liter
0 16
019
108
124
Precision as
Standard Deviation
mg N/hter
0092
0083
0245
0214
Accuracy as
Bias,
-679
+ 830
+412
+ 282
Bias,
mg N/lrter
-001
+002
+004
+004
(FWPCA Method Study 2, Nutrient Analyses)
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 427,
Method 419D (1975)
2 Annual Book of ASTM Standards, Part 31, "Water", Standard D 992-71, p 363 (1976)
3 Jenkins, D , and Medsken, L, "A Brucine Method for the Determination of Nitrate in Ocean,
Estuanne, and Fresh Waters", Anal Chem , 36, p 610, (1964)
352 1-3
-------
NITROGEN, NITRATE-NITRITE
Method 353.1 (Colorimetric, Automated, Hydrazine Reduction)
STORET NO. Total 00630
Scope and Application
1 1 This method is applicable to drinking and surface water, and domestic and industrial
wastes The applicable range of this method is 0 01-10 mg/1 nitrate-nitrite nitrogen
Approximately 20 samples per hour can be analyzed
Summary of Method
2 1 Nitrate is reduced to nitrite with hydrazme sulfate and the nitrite (that originally present
plus reduced nitrate) is determined by diazotizing with sulfamlamide and coupling with
N-(l-naphthyl)-ethylenediamme dihydrochlonde to form a highly colored azo dye
which is measured colonmetrically
Sample Handling and Preservation
3 1 Analysis should be made as soon as possible If analysis can be made within 24 hours,
samples should be preserved by refrigeration at 4°C When samples must be stored for
more than 24 hours, they should be preserved with 2 ml of sulfunc acid (H2SO4) per liter
and refrigerated
Interferences
4 1 Sample color that absorbs in the photometric range used for analysis will interfere
4 2 The apparent NO3 and NO2 concentrations varied ±10 percent with concentrations of
sulfide ion up to 10 mg/1
Apparatus
5 1 Sampler
5 2 Manifold AAI or AAII
5 3 Proportioning Pump
5 4 Heating bath 32°C AAI or 37°C AAII
5 5 Continuous filter
5 6 Colorimeter equipped with an 8 mm, 15 mm or 50 mm flow cell and 529 nm filters
Reagents
6 1 Color developing reagent To approximately 500 ml of distilled water add 200 ml
concentrated phosphoric acid (sp gr 1 834), 10 g sulfamlamide (H2NC6H4SO2NH2)
followed by 0 8 g N (1-Naphthyl) ethylenediamme dihydrochlonde Dilute the solution
to 1 liter with distilled water and store in a dark bottle in the refrigerator This solution is
stable for approximately 1 month
6 2 Copper sulfate stock solution Dissolve 2 5 g of copper sulfate (CuSO4«5H2O) in
distilled water and dilute to 1 liter
Approved for NPDES and SDWA
Issued 1971
Reissued with revision 1978
353 1-1
-------
6 3 Copper sulfate dilute solution Dilute 20 ml of stock solution (6 2) to 2 liters with distilled
water
6.4 Sodium hydroxide stock solution, (ION) Dissolve 400 g NaOH m 750 ml distilled water,
cool and dilute to 1 liter
6 5 Sodium hydroxide (1 ON) Dilute 100 ml of stock NaOH solution (6 4) to 1 liter
6 6 Hydrazme sulfate stock solution Dissolve 27 5 g of hydrazine sulfate (N2H4«H2SO4) in
900 ml of distilled water and dilute to 1 liter This solution is stable for approximately 6
months CAUTION Toxic if ingested Mark container with appropriate warning
6 7 Hydrazme sulfate dilute solution
671 AAI Dilute 55 ml of stock solution (6 6) to 1 liter
672 AAII Dilute 22 ml of stock solution (6 6) to 1 liter
6 8 Stock nitrate solution (100 mg/1 NO3-N) Dissolve 0 7218 g of KNO3, oven dried at
100-105°C for 2 hours, in distilled water and dilute to 1 liter Add 1 ml chloroform as a
preservative Stable for 6 months 1 ml = 0 1 mg N
6.9 Stock nitrite solution (100 mg/1 NO2-N) Dissolve 0 6072 g KNO2 in 500 ml of distilled
water and dilute to 1 liter Preserve with 2 ml of chloroform and keep under refrigeration
1 ml = 0 1 mg N
6 10 Standard nitrate solution Dilute 100 ml of stock nitrate solution (6 8) to 1 liter 1 ml =
OOlmgN
6 11 Using the stock nitrate solution (6 8), prepare the following standards in 100 ml
volumetric flasks At least one nitrite standard should be compared to a nitrate standard
at the concentration to verify the efficiency of the reduction
Cone, mg NO3-N/1 ml of stock solution/100 ml
05 05
10 10
20 20
30 30
40 40
50 50
80 80
100 100
For standards in the range of 0 01 mg/1 use the standard nitrate solution
7. Procedure
7.1 Set up the manifold as shown in Figure 1 (AAI) or Figure 2 (AAII) The continuous
filter must be used to remove the precipitate
7 2 Allow both colorimeter and recorder to warm up for 30 minutes Obtain a stable baseline
with all reagents, feeding distilled water through the sample line
7 3 Run a 2 0 mg/1 NO3-N and a 2 0 mg/1 NO2-N standard through the system to check for
100% reduction of nitrate to nitrite The two peaks should be of equal height If they are
not, the concentration of the hydrazine sulfate solution must be adjusted as follows If the
NO3 peak is lower than that of the NO2 peak the concentration of hydrazine sulfate
should be increased until they are equal If the NO3 peak is higher than the nitrite, the
concentration of the hydrazine sulfate should be reduced When the correct
353 1-2
-------
concentration of hydrazme sulfate has been determined, no further adjustment should be
necessary
7 4 Place appropriate nitrate standards in the sampler in order of decreasing concentration
of nitrogen Complete loading tray with unknown samples
7 5 For both the AAI and the AAII use a 2 minute sampling rate
8 Calculation
8 1 Prepare a standard curve by plotting peak heights of processed standards against known
concentrations Compute concentrations of samples by comparing sample peak heights
with the standard curve
9 Precision and Accuracy
91 In a single laboratory using drinking water, surface water and industrial waste at
concentrations of 0 39, 115, 1 76 and 4 75 ug NO3-N/1, the standard deviations
were +002, ±001, ±002 and +0 03, respectively In a single laboratory using drinking
water at concentrations of 0 75 and 2 97 the recoveries were 99% and 101%
Bibliography
1 Kamphake, L , Hannah, S , and Cohen, J , "Automated Analysis For Nitrate by Hydrazme
Reduction", Water Research 1,205 (1967)
353 1-3
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NITROGEN, NITRATE-NITRITE
Method 353.2 (Colorimetric, Automated, Cadmium Reduction)
STORET NO. Total 00630
1 Scope and Application
1 1 This method pertains to the determination of nitrite singly, or nitrite and nitrate
combined m surface and saline waters, and domestic and industrial wastes The
applicable range of this method is 0 05 to 10 0 mg/1 nitrate-nitrite nitrogen The range
may be extended with sample dilution
2 Summary of Method
21 A filtered sample is passed through a column containing granulated copper-cadmium to
reduce nitrate to nitrite The nitrite (that originally present plus reduced nitrate) is
determined by diazotizing with sulfamlamide and coupling with N-(l-naphthyl)-
ethylenediamme dihydrochlonde to form a highly colored azo dye which is measured
colonmetncally Separate, rather than combined nitrate-nitrite, values are readily
obtained by carrying out the procedure first with, and then without, the Cu-Cd reduction
step
3 Sample Handling and Preservation
3 1 Analysis should be made as soon as possible If analysis can be made within 24 hours, the
sample should be preserved by refrigeration at 4°C When samples must be stored for
more than 24 hours, they should be preserved with sulfuric acid (2 ml cone H2SO4 per
liter) and refrigeration
Caution Samples for reduction column must not be preserved with mercuric chloride
4 Interferences
4 1 Build up of suspended matter in the reduction column will restrict sample flow Since
nitrate-nitrogen is found in a soluble state, the sample may be pre-filtered
4 2 Low results might be obtained for samples that contain high concentrations of iron,
copper or other metals EDTA is added to the samples to eliminate this interference
4 3 Samples that contain large concentrations of oil and grease will coat the surface of the
cadmium This interference is eliminated by pre-extracting the sample with an organic
solvent
5 Apparatus
5 1 Techmcon Auto Analyzer (A AI or A All) consisting of the following components
511 Sampler
512 Manifold (AAI) or analytical cartridge (AAII)
513 Proportioning Pump
5 1 4 Colorimeter equipped with a 15 mm or 50 mm tubular flow cell and 540 nm filters
515 Recorder
Approved for NPDES and SDWA
Issued 1971
Editorial revision 1974 and 1978
353 2-1
-------
516 Digital printer for AAII (Optional)
6. Reagents
6 1 Granulated cadmium 40-60 mesh (MCB Reagents)
6 2 Copper-cadmium The cadmium granules (new or used) are cleaned with dilute HC1
(6 7) and coppenzed with 2% solution of copper sulfate (6 8) in the following manner
6 2 1 Wash the cadmium with HC1 (6 7) and rinse with distilled water The color of the
cadmium so treated should be silver
622 Swirl 10 g cadmium in 100 ml portions of 2% solution of copper sulfate (6 8) for
five minutes or until blue color partially fades, decant and repeat with fresh copper
sulfate until a brown colloidal precipitate forms
623 Wash the cadmium-copper with distilled water (at least 10 times) to remove all the
precipitated copper The color of the cadmium so treated should be black
6.3 Preparation of reduction column AAI The reduction column is an 8 by 50 mm glass tube
with the ends reduced in diameter to permit insertion into the system Copper-cadmium
granules (6 2) are placed in the column between glass wool plugs The packed reduction
column is placed m an up-flow 20° incline to minimize channeling See Figure 1
6 4 Preparation of reduction column AAII The reduction column is a U-shaped, 35 cm
length, 2 mm I D glass tube (frote* 1) Fill the reduction column with distilled water to
prevent entrapment of air bubbles during the filling operations Transfer the copper-
cadmium granules (6 2) to the reduction column and place a glass wool plug in each end
To prevent entrapment of air bubbles in the reduction column be sure that all pump tubes
are filled with reagents before putting the column into the analytical system
NOTE 1: A 0 0811D pump tube (purple) can be used in place of the 2 mm glass tube
6 5 Distilled water Because of possible contamination, this should be prepared by passage
through an ion exchange column comprised of a mixture of both strongly acidic-cation
and strongly basic-amon exchange resms The regeneration of the ion exchange column
should be earned out according to the manufacturer's instructions
6.6 Color reagent To approximately 800 ml of distilled water, add, while stirring, 100 ml
cone phosphoric acid, 40 g sulfamlamide, and 2 g N-1-naphthylethylenediamme
dihydrochlonde Stir .until dissolyed and dilute to 1 liter Store in brown bottle and keep
m the dark when not in use This solution is stable for several months
6.7 Dilute hydrochloric acid, 6N Dilute 50 ml of cone HC1 to 100 ml with distilled water
6 8 Copper sulfate solution, 2% Dissolve 20 g of CuSO4«5H2O in 500 ml of distilled water
and dilute to 1 liter
6 9 Wash solution Use distilled water for unpreserved samples For samples preserved with
H2SO4, use 2 ml H2SO4 per liter of wash water
6 10 Ammonium chlonde-EDT,A splution Dissolve 85 g of reagent grade ammonium
chloride and 0 1 g of disodium ethylened'iamme tetracetate in 900 ml of distilled water
Adjust the pH to 8 5 with cone ammonium hydroxide and dilute to 1 liter Add 1/2 ml
Bnj-35 (available from Techmcon Corporation)
353 2-2
-------
INDENTATIONS FOR
SUPPORTING CATALYST
GLASS WOOL
Cd-TURNINGS
TILT COLUMN TO 20° POSTION
FIGURE 1. COPPER CADMIUM REDUCTION COLUMN
(1 1/2 ACTUAL SIZE)
353 2-3
-------
6 11. Stock nitrate solution Dissolve 7 218 g KNO3 and dilute to 1 liter m a volumetric flask
with distilled water Preserve with 2 ml of chloroform per liter Solution is stable for 6
months 1 ml = 1 0 mg NO3-N
6 12 Stock nitrite solution Dissolve 6 072 g KNO2 in 500 ml of distilled water and dilute to 1
liter in a volumetric flask Preserve with 2 ml of chloroform and keep under refrigeration
10ml= 10mgNO2-N
6 13 Standard nitrate solution Dilute 10 0 ml of stock nitrate solution (6 11) to 1000 ml
10 ml = 001mgNO3-N Preserve with 2 ml of chloroform per liter Solution is stable
for 6 months
6 14 Standard nitrite solution Dilute 10 0 ml of stock nitrite (6 12) solution to 1000 ml
1 0 ml = 0 01 mgNO2-N Solution is unstable, prepare as required
6 15 Using standard nitrate solution (6 13), prepare the following standards in 1000 ml
volumetric flasks At least one nitrite standard should be compared to a nitrate standard
at the same concentration to verify the efficiency of the reduction column
Cone, mgNO2-N or NO3-N/1
00
005
010
020
050
100
200
400
600
ml Standard Solution/100 ml
0
05
10
20
50
100
200
400
600
NOTE 2' When the samples to be analyzed are saline waters, Substitute Ocean Water
(SOW) .should be used for preparing the standards, otherwise, distilled water is used A
tabulation of SOW composition follows
NaCl - 24 53 g/1
CaCl2 - 1 16 g/1
KBr - 0 10 g/1
NaF - 0 003 g/1
MgCl2 - 5 20 g/1
KC1 - 0 70 g/1
H3B03 - 0 03 g/1
Na2S04 - 4 09 g/1
NaHCO3 - 0 20 g/1
SrCl2 - 0 03 g/1
Procedure
7 1 If the pH of the sample is below 5 or above 9, adjust to between 5 and 9 with either cone
HClorconc NH4OH
Set up the manifold as shown m Figure 2 (AAI) or Figure 3 (AAII) Note that reductant
column should be in 20° incline position (AAI) Care should be taken not to introduce air
into reduction column on the AAII
Allow both colorimeter and recorder to warm up for 30 minutes Obtain a stable baseline
with all reagents, feeding distilled water through the sample line
NOTE 3: Condition column by running 1 mg/1 standard for 10 minutes if a new
reduction column is being used Subsequently wash the column with reagents for 20
minutes
72
73
353 2-4
-------
3
4
7 4 Place appropriate nitrate and/or nitrite standards in sampler in order of decreasing
concentration of nitrogen Complete loading of sampler tray with unknown samples
7 5 For the AAI system, sample at a rate of 30/hr, 1 1 For the AAII, use a 40/hr, 4 1 cam
and a common wash
7 6 Switch sample line to sampler and start analysis
Calculations
8 1 Prepare appropriate standard curve or curves derived from processing NO2 and/or NO3
standards through manifold Compute concentration of samples by comparing sample
peak heights with standard curve
Precision and Accuracy
9 1 Three laboratories participating in an EPA Method Study, analyzed four natural water
samples containing exact increments of inorganic nitrate, with the following results
Increment as
Nitrate Nitrogen
mg N/hter
029
035
231
248
Precision as
Standard Deviation
mg N/hter
0012
0092
0318
0176
Accuracy as
Bias,
+ 575
+ 18 10
+ 447
-269
Bias,
mg N/hter
+0017
+0063
+0103
-0067
Bibliography
Fiore, J, and O'Brien, J E, "Automation m Sanitary Chemistry - parts 1 & 2 Determination
of Nitrates and Nitrites", Wastes Engineering 33, 128 & 238 (1962)
Armstrong, F A, Stearns, C R, and Strickland, J D , "The Measurement of Upwellmg and
Subsequent Biological Processes by Means of the Techmcon AutoAnalyzer and Associated
Equipment", Deep Sea Research 14, p 381-389 (1967)
Annual Book of ASTM Standards, Part 31, "Water", Standard D1254, p 366 (1976)
Chemical Analyses for Water Quality Manual, Department of the Interior, FWPCA, R A
Taft Sanitary Engineering Center Training Program, Cincinnati, Ohio 45226 (January, 1966)
Annual Book of ASTM Standards, Part 31, "Water", Standard D 1141-75, Substitute Ocean
Water, p 48 (1976)
353 2-5
-------
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NITROGEN, NITRATE-NITRITE
Method 353.3 (Spectrophotometric, Cadmium Reduction)
STORET NO. Total 00630
Scope and Application
1 1 This method is applicable to the determination of nitrite singly, or nitrite and nitrate
combined in drinking, surface and saline waters, domestic and industrial wastes The
applicable range of this method is 0 01 to 1 0 mg/1 nitrate-nitrite nitrogen The range
may be extended with sample dilution
Summary of Method
21 A filtered sample is passed through a column containing granulated copper-cadmium to
reduce nitrate to nitrite The nitrite (that originally present plus reduced nitrate) is
determined by diazotizmg with sulfamlamide and coupling with N-(l-naphthyl)-
ethylenediamme dihydrochlonde to form a highly colored azo dye which is measured
spectrophotometncally Separate, rather than combined nitrate-nitrite, values are readily
obtained by carrying out the procedure first with, and then without, the Cu-Cd reduction
step
Sample Handling and Preservation
3 1 Analysis should be made as soon as possible If analysis can be made within 24 hours, the
sample should be preserved by refrigeration at 4°C When samples must be stored for
more than 24 hours, they should be preserved with sulfunc acid (2 ml H2SO4 per liter)
and refrigeration
Caution Samples for reduction column must not be preserved with mercuric chloride
Interferences
4 1 Build up of suspended matter in the reduction column will restrict sample flow Since
nitrate-nitrogen is found in a soluble state, the sample may be pre-filtered through a glass
fiber filter or a 0 45 u membrane filter Highly turbid samples may be pretreated with zinc
sulfate before filtration to remove the bulk of particulate matter present m the sample
4 2 Low results might be obtained for samples that contain high concentrations of iron,
copper or other metals EDTA is added to the samples to eliminate this interference
4 3 Samples that contain large concentrations of oil and grease will coat the surface of the
cadmium This interference is eliminated by pre-extracting the sample with an organic
solvent
4 4 This procedure determines both nitrate and mtnte If only nitrate is desired, a separate
determination must be made for nitrite and subsequent corrections made The nitrite
may be determined by the procedure below without the reduction step
Approved for NPDES and SDWA
Issued 1974
353 3-1
-------
5. Apparatus
5 1 Reduction column The column in Figure I was constructed from a 100 ml pipet by
removing the top portion This column may also be constructed from two pieces of
tubing joined end to end A 10 mm length of 3 cm I D tubing is joined to a 25 cm length
of 3 5 mm I D tubing
5 2 Spectrophotometer for use at 540 nm, providing a light path of 1 cm or longer
6. Reagents
6.1 Granulated cadmium 40-60 mesh (MCB Reagents)
6 2 Copper-Cadmium The cadmium granules (new or used) are cleaned with dilute HC1 and
coppenzed with 2% solution of copper sulfate m the following manner
621 Wash the cadmium with dilute HC1 (6 10) and rinse with distilled water The color
of the cadmium should be silver
622 Swirl 25 g cadmium in 100 ml portions of a 2% solution of copper sulfate (6 11) for
5 minutes or until blue color partially fades, decant and repeat with fresh copper
sulfate until a brown colloidal precipitate forms
623 Wash the copper-cadmium with distilled water (at least 10 times) to remove all the
precipitated copper The color of the cadmium so treated should be black
6 3 Preparation of reaction column Insert a glass wool plug into the bottom of the reduction
column and fill with distilled water Add sufficient copper-cadmium granules to produce
a column 18 5 cm in length Maintain a level of distilled water above the copper-
cadmium granules to eliminate entrapment of air Wash the column with 200 ml of dilute
ammonium chloride solution (6 5) The column is then activated by passing through the
column 100 ml of a solution composed of 25 ml of a 1 0 mg/1 NO3-N standard and 75 ml
of ammonium chloride - EDTA solution (6 4) Use a flow rate between 7 and 10 ml per
minute
6.4 Ammonium chloride - EDTA solution Dissolve 13 g ammonium chloride and 1 7 g
disodium ethylenediamme tetracetate in 900 ml of distilled water Adjust the pH to 8 5
with cone ammonium hydroxide (6 9) and dilute to 1 liter
6 5 Dilute ammonium chlonde-EDTA solution Dilute 300 ml of ammonium chlonde-
EDTA solution (6 4) to 500 ml with distilled water
6 6 Color reagent Dissolve 10 g sulfamlamide and 1 g N(l-naphthyl)-ethylene-diamme
dihydrochlonde in a mixture of 100 ml cone phosphoric acid and 800 ml of distilled
water and dilute to 1 liter with distilled water
6 7 Zmc sulfate solution Dissolve 100 g ZnSO4«7H2O in distilled water and dilute to 1 liter
6 8 Sodium hydroxide solution, 6N Dissolve 240 g NaOH in 500 ml distilled water, cool and
dilute to 1 liter
6 9 Ammonium hydroxide, cone
6 10 Dilute hydrochloric acid, 6N Dilute 50 rnl of cone HC1 to 100 ml with distilled water
6 11 Copper sulfate solution, 2% Dissolve 20 g of CuSO4«5H2O in 500 ml of distilled water
and dilute to 1 liter
6 12 Stock nitrate solution Dissolve 7 218 g KNO3 in distilled water and dilute to 1000 ml
Preserve with 2 ml of chloroform per liter This solution is stable for at least 6 months
10ml= 100mgNO3-N
353 3-2
-------
10cm
80-85 ml
3cm I D
3 5 mm I D.
GLASS WOOL PLUG
FIGURE 1. REDUCTION COLUMN
353 3-3
-------
6.13 Standard nitrate solution Dilute 10 0 ml of nitrate stock solution (6 12) to 1000 ml with
distilled water 1 0 ml = 0 01 mg NO3-N
6.14 Stock nitrite solution Dissolve 6 072 g KNO2 in 500 ml of distilled water and dilute to
1000 ml Preserve with 2 ml of chloroform and keep under refrigeration Stable for
approximately 3 months 1 0 ml = 1 00 mg NO2-N
6 15 Standard nitrite solution Dilute 10 0 ml of stock mtnte solution (6 14) to 1000 ml with
distilled water 1 0 ml = 0 01 mg NO2-N
6 16 Using standard nitrate solution (6 13) prepare the following standards in 100 ml
volumetric flasks
Cone, mg-N03-N/l ml of Standard Solution/1000 ml
000 00
005 05
010 10
020 20
050 50
100 100
Procedure
7 1 Turbidity removal One of the following methods may be used to remove suspended
matter
7 1 1 Filter sample through a glass fiber filter or a 0 45u membrane filter
7 1.2 Add 1 ml zinc sulfate solution (6 7) to 100 ml of sample and mix thoroughly Add
0 4-0 5 ml sodium hydroxide solution (6 8) to obtain a pH of 10 5 as determined
with a pH meter Let the treated sample stand a few minutes to allow the heavy
flocculent precipitate to settle Clarify by filtering through a glass fiber filter or a
0 45 u membrane filter
7 2 Oil and grease removal Adjust the pH of 100 ml of filtered sample to 2 by addition of
cone HC1 Extract the oil and grease from the aqueous solution with two 25 ml portions
of a non-polar solvent (Freon, chloroform or equivalent)
7.3 If the pH of the sample is below 5 or above 9, adjust to between 5 and 9 with either cone
HC1 or cone NH^OH This is done to insure a sample pH of 8 5 after step 7 4
7.4 To 25 0 ml of sample or an aliquot diluted to 25 0 ml, add 75 ml of ammonium chlonde-
EDTA solution (6 4) and mix
7.5 Pour sample into column and collect sample at a rate of 7-10 ml per minute
7 6 Discard the first 25 ml, collect the rest of the sample (approximately 70 ml) in the
original sample flask Reduced samples should not be allowed to stand longer than 15
minutes before addition of color reagent, step 7 7
7 7 Add 2 0 ml of color reagent (6 6) to 50 0 ml of sample Allow 10 minutes for color
development Within 2 hours measure the absorbance at 540 nm against a reagent blank
NOTE: If the concentration of sample exceeds 1 0 mg NO3-N/1, the remainder of the
reduced sample may be used to make an appropriate dilution before proceeding with step
353 3-4
-------
7 8 Standards Carry out the reduction of standards exactly as described for the samples At
least one nitrite standard should be compared to a reduced nitrate standard at the same
concentration to verify the efficiency of the reduction column
Calculation
8 1 Obtain a standard curve by plotting the absorbance of standards run by the above
procedure against NO3-N mg/1 Compute concentration of samples by comparing
sample absorbance with standard curve
82 If less than 25 ml of sample is used for the analysis the following equation should be used
rngNO, + N03 - N/l =
ml
where
A = Concentration of nitrate from standard curve
9 Precision and Accuracy
91 In a single laboratory (EMSL), using sewage samples at concentrations of 0 04,0 24,0 55
and 1 04 mg NO3 + NO2-N/1, the standard deviations were ±0 005, ±0 004, ±0 005
and _±0 01, respectively
92 In a single laboratory (EMSL), using sewage samples at concentrations of 0 24,0 55, and
1 05 mg NO3 + NO2-N/1, the recoveries were 100%, 102% and 100%, respectively
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 423,
Method 419C (1975)
2 Hennkson, A , and Selmer-Olsen, "Automatic Methods for Determining Nitrate and Nitrite in
Water and Soil Extracts" Analyst, May 1970, Vol 95,p514-518
3 Grasshoff, K , "A Simultaneous Multiple Channel System for Nutrient Analysis in Sea Water
with Analog and Digital Data Record", "Advances in Automated Analysis", Techmcon
International Congress, 1969, Vol 11, p 133-145
4 Brewer, P G, Riley, J P , "The Automatic Determination of Nitrate in Sea Water", Deep Sea
Research, 1965, Vol 12, p 765-772
353 3-5
-------
NITROGEN, NITRITE
Method 354.1 (Spectrophotometric)
STORET NO. Total 00615
1 Scope and Application
1 1 This method is applicable to the determination of nitrite in drinking, surface and saline
waters, domestic and industrial wastes
1 2 The method is applicable in the range from 0 01 to 1 0 mg NO2-N/1
2 Summary of Method
2 1 The diazonmm compound formed by diazotation of sulfamlamide by nitrite in water
under acid conditions is coupled with N-(l-naphthyl)-ethylenediamme dihydrochlonde
to produce a reddish-purple color which is read in a spectrophotometer at 540 nm
3 Sample Handling and Preservation
3 1 Samples should be analyzed as soon as possible They may be stored for 24 to 48 hours at
4°C
4 Interferences
4 1 There are very few known interferences at concentrations less than 1,000 times that of
the nitrite, however, the presence of strong oxidants or reductants in the samples will
readily affect the nitrite concentrations High alkalinity (>600 mg/1) will give low
results due to a shift in pH
5 Apparatus
5 1 Spectrophotometer equipped with 1 cm or larger cells for use at 540 nm
5 2 Nessler tubes, 50 ml or volumetric flasks, 50 rnl
6 Reagents
6 1 Distilled water free of nitrite and nitrate is to be used in preparation of all reagents and
standards
6 2 Buffer-color reagent To 250 ml of distilled water, add 105 ml cone hydrochloric acid,
5 0 g sulfamlamide and 0 5 g N-(l-naphthyl) ethylenediamme dihydrochlonde Stir until
dissolved Add 136 g of sodium acetate (CH3COONa«3H2O) and again stir until
dissolved Dilute to 500 ml with distilled water This solution is stable for several weeks if
stored in the dark
6 3 Nitrite stock solution 1 0 ml = 0 10 mg NO2-N Dissolve 0 1493 g of dried anhydrous
sodium nitrite (24 hours in desiccator) in distilled water and dilute to 1000 ml Preserve
with 2 ml chloroform per liter
6 4 Nitrite standard solution 1 0 ml = 0 001 mg NO2-N Dilute 10 0 ml of the stock
solution (6 3) to 1000 ml
7 Procedure
71 If the sample has a pH greater than 10 or a total alkalinity in excess of 600 mg/1, adjust
to approximately pH 6 with 1 3 HC1
Approved for NPDES
Issued 1971
354 1-1
-------
7.2 If necessary, filter the sample through a 0 45 u pore size filter using the first portion of
filtrate to rinse the filter flask
7 3 Place 50 ml of sample, or an aliquot diluted to 50 ml, in a 50 ml Nessler tube, hold until
preparation of standards is completed
74 At the same time prepare a series of standards in 50 ml Nessler tubes as follows
ml of Standard Solution Cone, When Diluted to
10 ml = 0001 mgNO2-N 50 ml, mg/1 of NO2-N
0 0 (Blank)
05 001
10 002
15 003
20 004
30 006
40 008
50 010
10 0 0 20
7 5 Add 2 ml of buffer-color reagent (6 2) to each standard and sample, mix and allow color
to develop for at least 15 minutes The color reaction medium should be between pH 1 5
and 20
7.6 Read the color in the spectrophotometer at 540 nm against the blank and plot
concentration of NO2-N against absorbance
8. Calculation
8 1 Read the concentration of NO2-N directly from the curve
8 2 If less than 50 0 ml of sample is taken, calculate mg/1 as follows
Mr» M „/! mg/1 from std curve x 50
N02 - N, mg/1 = mlsampleused
9 Precision and Accuracy
9 1 Precision and Accuracy data are not available at this time
Bibliography
1 Standard Methods for the Examination for Water and Wastewater, 14th Edition, p 434,
Method 420, (1975)
354 1-2
-------
OXYGEN, DISSOLVED
Method 360.1 (Membrane Electrode)
STORET NO. 00299
1 Scope and Application
1 1 The probe method for dissolved oxygen is lecommended for those samples containing
materials which interfere with the modified Wmkler procedure such as sulfite,
thiosulfate, polythionate, mercaptans, free chlorine or hypochlonte, organic substances
readily hydrolyzed in alkaline solutions, free iodine, intense color or turbidity and
biological floes
1 2 The probe method is recommended as a substitute for the modified Wmkler procedure in
monitoring of streams, lakes, outfalls, etc, where it is desired to obtain a continuous
record of the dissolved oxygen content of the water under observation
1 3 The probe method may be used as a substitute for the modified Wmkler procedure in
BOD determinations where it is desired to perform nondestructive DO measurements on
a sample
1 4 The probe method may be used under any circumstances as a substitute for the modified
Wmkler procedure provided that the probe itself is standardized against the Wmkler
method on samples free of interfering materials
1 5 The electronic readout meter for the output from dissolved oxygen probes is normally
calibrated in convenient scale (0 to 10, 0 to 15, 0 to 20 mg/1 for example) with a
sensitivity of approximately 0 05 mg/hter
2 Summary of Method
2 1 The most common instrumental probes for determination of dissolved oxygen in water
are dependent upon electrochemical reactions Under steady-state conditions, the
current or potential can be correlated with DO concentrations Interfacial dynamics at
the probe-sample interface are a factor in probe response and a significant degree of
mterfacial turbulence is necessary For precision performance, turbulence should be
constant
3 Sample Handling and Preservation
31 See 4 1,4 2,4 3,4 4 under Modified Wmkler Method (360 2)
4 Interferences
4 1 Dissolved organic materials are not known to interfere in the output from dissolved
oxygen probes
4 2 Dissolved inorganic salts are a factor in the performance of dissolved oxygen probe
421 Probes with membranes respond to partial pressure of oxygen which in turn is a
function of dissolved inorganic salts Conversion factors for seawater and brackish
waters may be calculated from dissolved oxygen saturation versus salinity data
Conversion factors for specific inorganic salts may be developed experimentally
Approved for NPDES
Issued 1971
360 1-1
-------
Broad variations in the kinds and concentrations of salts in samples can make the
use of a membrane probe difficult
4 3 Reactive compounds can interfere with the output or the performance of dissolved
oxygen probes
431 Reactive gases which pass through the membrane probes may interfere For
example, chlorine will depolarize the cathode and cause a high probe-output
Long-term exposures to chlorine will coat the anode with the chloride of the anode
metal and eventually desensitize the probe Alkaline samples in which free chlorine
does not exist will not interfere Hydrogen sulfide will interfere with membrane
probes if the applied potential is greater than the half-wave potential of the sulfide
ion If the applied potential is less than the half-wave potential, an interfering
reaction will not occur, but coating of the anode with the sulfide of the anode metal
can take place
4 4 Dissolved oxygen probes are temperature sensitive, and temperature compensation is
normally provided by the manufacturer Membrane probes have a temperature
coefficient of 4 to 6 percent/°C dependent upon the membrane employed
5 Apparatus
5 1 No specific probe or accessory is especially recommended as superior However, probes
which have been evaluated or are in use and found to be reliable are the Weston & Stack
DO Analyzer Model 30, the Yellow Springs Instrument (YSI) Model 54, and the
Beckman Fieldlab Oxygen Analyzer
6, Calibration
Follow manufacturer instructions
7. Procedure
Follow manufacturer instructions
8. Calculation
Follow manufacturer instructions
9. Precision and Accuracy
Manufacturer's specification claim 0 1 mg/1 repeatability with ± 1 % accuracy
Bibliography
1 Standard Methods for the Examination of Watef and Wastewater, 14th Edition, p 450,
Method 422F (1975)
360 1-2
-------
OXYGEN, DISSOLVED
Method 360.2 (Modified Winkler, Full-Bottle Technique)
STORET NO. 00300
Scope and Application
1 1 This method is applicable for use with most wastewaters and streams that contain nitrate
nitrogen and not more than 1 mg/1 of ferrous iron Other reducing of oxidizing materials
should be absent If 1 ml of fluoride solution is added before acidifying the sample and
there is no delay in titration, the method is also applicable in the presence of 100-200
mg/1 ferric iron
1 2 The Dissolved Oxygen (DO) Probe technique gives comparable results on all samples
types
1 3 The azide modification is not applicable under the following conditions (a) samples
containing sulfite, thiosulfate, polythionate, appreciable quantities of free chlorine or
hypochlonte, (b) samples high in suspended solids, (c) samples containing organic
substances which are readily oxidized in a highly alkaline solution, or which are oxidized
by free iodine in an acid solution, (d) untreated domestic sewage, (e) biological floes, and
(f) where sample color interferes with endpomt detection In instances where the azide
modification is not applicable, the DO probe should be used
Summary of Method
2 1 The sample is treated with manganous sulfate, potassium hydroxide, and potassium
iodide (the latter two reagents combined in one solution) and finally sulfunc acid The
initial precipitate of manganous hydroxide, Mn(OH)2, combines with the dissolved
oxygen in the sample to form a brown precipitate, manganic hydroxide, MnO(OH)2
Upon acidification, the manganic hydroxide forms manganic sulfate which acts as an
oxidizing agent to release free iodine from the potassium iodide The iodine, which is
stoichiometncally equivalent to the dissolved oxygen in the sample is then titrated with
sodium thiosulfate or phenylarsme oxide (PAO)
Interferences
3 1 There are a number of interferences to the dissolved oxygen test, including oxidizing and
reducing agents, nitrate ion, ferrous iron, and organic matter
3 2 Various modifications of the original Wmkler procedure for dissolved oxygen have been
developed to compensate for or eliminate interferences The Alsterberg modification is
commonly used to successfully eliminate the nitrite interference, the Rideal-Stewart
modification is designed to eliminate ferrous iron interference, and the Thenault
procedure is used to compensate for high concentration of organic materials
3 3 Most of the common interferences in the Winkler procedure may be overcome by use of
the dissolved oxygen probe
Approved for NPDES
Issued 1971
360 2-1
-------
4. Sample Handling and Preservation
4 1 Where possible, collect the sample in a 300 ml BOD incubation bottle Special
precautions are required to avoid entramment or solution of atmospheric oxygen or loss
of dissolved oxygen
4 2 Where samples are collected from shallow depths (less than 5 feet), use of an APHA-type
sampler is recommended Use of a Kemmerer type sampler is recommended for samples
collected from depths of greater than 5 feet
4 3 When a Kemmerer sampler is used, the BOD sample bottle should be filled to
overflowing (overflow for approximately 10 seconds) Outlet tube of Kemmerer should
be inserted to bottom of BOD bottle Care must be taken to prevent turbulence and the
formation of bubbles when filling bottle
4.4 At time of sampling, the sample temperature should be recorded as precisely as required
4.5 Do not delay the determination of dissolved oxygen in samples having an appreciable
iodine demand or containing ferrous iron If samples must be preserved either method
(4 5 1) or (4 5 2) below, may be employed
4.5 1 Add 2 ml of manganous sulfate solution (6 1) and then 2 ml of alkaline lodide-azide
solution (6 2) to the sample contained in the BOD bottle Both reagents must be
added well below the surface of the liquid Stopper the bottle immediately and mix
the contents thoroughly The sample should be stored at the temperature of the
collection water, or water sealed and kept at a temperature of 10 to 20°C, in the
dark Complete the procedure by adding 2 ml H2SO4 (see 7 1) at time of analysis
4.5 2 Add 0 7 ml of cone H2SO4 (6 3) and 1 ml sodium azide solution (2 g NaN3 in 100
ml distilled water) to sample in the BOD bottle Store sample as in (4 5 1)
Complete the procedure using 2 ml of manganous sulfate solution (6 1), 3 ml
alkaline lodide-azide solution (6 2), and 2 ml of cone H2SO4 (6 3) at time of
analysis
4 6 If either preservation technique is employed, complete the analysis within 4-8 hours after
sampling
5. Apparatus
5 1 Sample bottles-300 ml ±3 ml capacity BOD incubation bottles with tapered ground
glass pointed stoppers and flared mouths
5.2 Pipets-with elongated tips capable of delivering 2 0 ml ±0 10 ml of reagent
6 Reagents
6 1 Manganous sulfate solution Dissolve 480 g manganous sulfate (MnSO4»4H2O in distilled
water and dilute to 1 liter
6 1 1 Alternatively, use 400 g of MnSO4«2H2O or 364 g of MnSO4»H2O per liter When
uncertainty exists regarding the water of crystallization, a solution of equivalent
strength may be obtained by adjusting the specific gravity of the solution to 1 270
at20°C
6 2 Alkaline lodide-azide solution Dissolve 500 g of sodium hydroxide (NaOH) or 700 g of
potassium hydroxide (KOH) and 135 g of sodium iodide (Nal) or 150 g of potassium
iodide (KI) in distilled water and dilute to 1 liter To this solution add 10 g of solution
azide (NaN3) dissolved in 40 ml of distilled water
360 2-2
-------
6 3 Sulfuric acid concentrated
6 4 Starch solution Prepare an emulsion of 10 g soluble starch in a mortar or beaker with a
small quantity of distilled water Pour this emulsion into 1 liter of boiling water, allow to
boil a few minutes, and let settle overnight Use the clear supernate This solution may be
preserved by the addition of 5 ml per liter of chloroform and storage in a 10°C
refrigerator
641 Dry, powdered starch indicators such as "thyodene" may be used m place of starch
solution
6 5 Potassium fluoride solution Dissolve 40 g KF«2H2O in distilled water and dilute to 100
ml
6 6 Sodium thiosulfate, stock solution, 0 75 N Dissolve 186 15 g Na2S2O3»5H2O in boiled
and cooled distilled water and dilute to 1 liter Preserve by adding 5 ml chloroform
6 7 Sodium thiosulfate standard titrant, 0 0375 N Prepare by diluting 50 0 ml of stock
solution to 1 liter Preserve by adding 5 ml of chloroform Standard sodium thiosulfate,
exactly 0 0375 N is equivalent to 0 300 mg of DO per 1 00 ml Standardize with 0 0375 N
potassium bnodate
6 8 Potassium bnodate standard, 0 0375 N For stock solution, dissolve 4 873 g of potassium
bnodate, previously dried 2 hours at 103°C, in 1000 ml of distilled water To prepare
working standard, dilute 250 ml to 1000 ml for 0 0375 N bnodate solution
6 9 Standardization of 0 0375 N sodium thiosulfate Dissolve approximately 2 g (± 1 0 g) KI
in 100 to 150 ml distilled water, add 10 ml of 10% H2SO4 followed by 20 0 ml standard
potassium bnodate (6 8) Place in dark for 5 minutes, dilute to 300 ml, and titrate with
the standard sodium thiosulfate (6 7) to a pale straw color Add 1-2 ml starch solution
and continue the titration drop by drop until the blue color disappears Run m duplicate
Duplicate determinations should agree within +0 05 ml
6 10 As an alternative to the sodium thiosulfate, phenylarsine oxide (PAO) may be used This
is available, already standardized, from commercial sources
7 Procedure
71 To the sample collected in the BOD incubation bottle, add 2 ml of the manganous sulfate
solution (61) followed by 2 ml of the alkaline lodide-azide solution (6 2), well below the
surface of the liquid, stopper with care to exclude air bubbles, and mix well by inverting
the bottle several times When the precipitate settles, leaving a clear supernatant above
the manganese hydroxide floe, shake again When settling has produced at least 200 ml
of clear supernatant, carefully remove the stopper and immediately add 2 ml of cone
H2SO4 (6 3) (sulfamic acid packets, 3 g may be substituted for H2SO4)C1) by allowing the
acid to run down the neck of the bottle, re-stopper, and mix by gentle inversion until the
iodine is uniformly distributed throughout the bottle Complete the analysis within 45
minutes
7 2 Transfer the entire bottle contents by inversion into a 500 ml wide mouth flask and titrate
with 0 0375 N thiosulfate solution (6 7) (0 0375 N phenyarsme oxide (PAO) may be
substituted as titrant) to pale straw color Add 1-2 ml of starch solution (6 4) or 0 1 g of
powdered indicator and continue to titrate to the first disappearance of the blue color
360 2-3
-------
73 If feme iron is present (100 to 200 mg/1), add 1 0 ml of KF (6 5) solution before
acidification
7 4 Occasionally, a dark brown or black precipitate persists in the bottle after acidication
This precipitate will dissolve if the solution is kept for a few minutes longer than usual or,
if particularly persistent, a few more drops of H2SO4 will effect dissolution
8. Calculation
8.1 Each ml of 0 0375N sodium thiosulfate (or PAO) titrant is equivalent to 1 mg DO when
the entire bottle contents are titrated
82 If the results are desired in milhhters of oxygen gas per liter at 0°C and 760 mm pressure
multiply mg/1 DObyO 698
83 To express the results as percent saturation at 760 mm atmospheric pressure, the
solubility data m Table 422 1 (Whipple & Whipple, p 446-447, Standard Methods, 14th
Edition) may be used Equations for correcting the solubilities to barometric pressures
other than mean sea level are given below the table
8 4 The solubility of DO in distilled water at any barometric pressure, p (mm Hg),
temperature, T°C, and saturated vapor pressure, u (mm Hg), for the given T, may be
calculated between the temperature of 0° and 30°C by
ml/1 DO =
35 + T
and between 30° and 50°C by
ml/! DO- (P "4}+XT° 82?
9 Precision and Accuracy
9 1 Exact data are unavailable on the precision and accuracy of this technique, however,
reproducibihty is approximately 0 2 mg/1 of DO at the 7 5 mg/1 level due to equipment
tolerances and uncompensated displacement errors
Bibliography
1 Kroner, R C, Longbottom, J E, Gorman, R A , "A Comparison of Various Reagents
Proposed for Use m the Winkler Procedure for Dissolved Oxygen", PHS Water Pollution
Surveillance System Applications and Development, Report #12, Water Quality Section,
Basic Data Branch, July 1964
2. Annual Book of ASTM Standards, Part 31, "Water", Standard D1589-60, Method A, p 373
(1976)
3, Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 443, method
422B(1975)
360 2-4
-------
PHOSPHORUS, ALL FORMS
Method 365.1 (Colorimetric, Automated, Ascorbic Acid)
STORET NO. See Section 4
Scope and Application
1 1 These methods cover the determination of specified forms of phosphorus in drinking,
surface and saline waters, domestic and industrial wastes
1 2 The methods are based on reactions that are specific for the orthophosphate ion Thus,
depending on the prescribed pre-treatment of the sample, the various forms of
phosphorus given in Figure 1 may be determined These forms are defined in Section 4
121 Except for in-depth and detailed studies, the most commonly measured forms are
phosphorus and dissolved phosphorus, and orthophosphate and dissolved
orthophosphate Hydrolyzable phosphorus is normally found only in sewage-type
samples Insoluble forms of phosphorus are determined by calculation
1 3 The methods are usable in the 0 01 to 1 0 mg P/l range Approximately 20-30 samples
per hour can be analyzed
Summary of Method
2 1 Ammonium molybdate and antimony potassium tartrate react in an acid medium with
dilute solutions of phosphorus to form an antimony-phospho-molybdate complex This
complex is reduced to an intensely blue-colored complex by ascorbic acid The color is
proportional to the phosphorus concentration
2 2 Only orthophosphate forms a blue color in this test Polyphosphates (and some organic
phosphorus compounds) may be converted to the orthophosphate form by manual
sulfunc acid hydrolysis Organic phosphorus compounds may be converted to the
orthophosphate form by manual persulfate digestion® The developed color is measured
automatically on the AutoAnalyzer
Sample Handling and Preservation
3 1 If benthic deposits are present in the area being sampled, great care should be taken not
to include these deposits
3 2 Sample containers may be of plastic material, such as cubitamers, or of Pyrex glass
33 If the analysis cannot be performed the same day of collection, the sample should be
preserved by the addition of 2 ml cone H2SO4 per liter and refrigeration at 4°C
Definitions and Storet Numbers
4 1 Total Phosphorus (P) - all of the phosphorus present in the sample regardless of form, as
measured by the persulfate digestion procedure (00665)
411 Total Orthophosphate (P-ortho)-morgamc phosphorus [(PO4X3] in the sample as
measured by the direct colonmetric analysis procedure (70507)
Approved for NPDES, pending approval for Section 304(h), CWA
Issued 1971
Editorial revision 1974 and 1978
365 1-1
-------
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365 1-2
-------
4 1 2 Total Hydrolyzable Phosphorus (P-hydro)-phosphorus in the sample as measured
by the sulfunc acid hydrolysis procedure, and minus predetermined
orthophosphates This hydrolyzable phosphorus includes polyphosphates
[(P2O7)'4, (P3O10)~5, etc ] plus some organic phosphorus (00669)
413 Total Organic Phosphorus (P-org)-phosphorus (inorganic plus oxidizable organic)
in the sample as measured by the persulfate digestion procedure, and minus
hydrolyzable phosphorus and orthophosphate (00670)
4 2 Dissolved Phosphorus (P-D) - all of the phosphorus present m the filtrate of a sample
filtered through a phosphorus-free filter of 0 45 micron pore size and measured by the
persulfate digestion procedure (00666)
4 2 1 Dissolved Orthophosphate (P-D, ortho) - as measured by the direct colonmetnc
analysis procedure (00671)
422 Dissolved Hydrolyzable Phosphorus (P-D, hydro) - as measured by the sulfuric
acid hydrolysis procedure and minus predetermined dissolved orthophosphates
(00672)
423 Dissolved Organic Phosphorus (P-D, org) - as measured by the persulfate
digestion procedure, and minus dissolved hydrolyzable phosphorus and
orthophosphate (00673)
4 3 The following forms, when sufficient amounts of phosphorus are present in the sample to
warrant such consideration, may be calculated
43 1 Insoluble Phosphorus (P-I)=(P)-(P-D) (00667)
4311 Insoluble orthophosphate (P-I, ortho)=(P, ortho) - (P-D, ortho)
(00674)
4312 Insoluble Hydrolyzable Phosphorus (P-I, hydro) = (P, hydro) - (P-
D, hydro) (00675)
4313 Insoluble Organic Phosphorus (P-I, org) = (P, org) - (P-D, org)
(00676)
4 4 All phosphorus forms shall be reported as P, mg/1, to the third place
Interferences
51 No interference is caused by copper, iron, or silicate at concentrations many times
greater than their reported concentration in sea water However, high iron
concentrations can cause precipitation of and subsequent loss of phosphorus
5 2 The salt error for samples ranging from 5 to 20% salt content was found to be less than
1%
5 3 Arsenate is determined similarly to phosphorus and should be considered when present
in concentrations higher than phosphorus However, at concentrations found in sea
water, it does not interfere
5 4 Sample turbidity must be removed by filtration prior to analysis for orthophosphate
Samples for total or total hydrolyzable phosphorus should be filtered only after
digestion Sample color that absorbs in the photometric range used for analysis will also
interfere
Apparatus
6 1 Techmcon Auto Analyzer consisting of
365 1-3
-------
611 Sampler
6 1 2 Manifold (AAI) or Analytical Cartridge (AAII)
613 Proportioning pump
614 Heating bath, 50°C
6.1 5 Colorimeter equipped with 15 or 50 mm tubular flow cell
616 650-660 or 880 nm filter
617 Recorder
6 1 8 Digital printer for AAII (optional)
6 2 Hot plate or autoclave
6.3 Acid-washed glassware All glassware used in the determination should be washed with
hot 1 1 HC1 and rinsed with distilled water The acid-washed glassware should be filled
with distilled water and treated with all the reagents to remove the last traces of
phosphorus that might be adsorbed on the glassware Preferably, this glassware should
be used only for the determination of phosphorus and after use it should be rinsed with
distilled water and kept covered until needed again If this is done, the treatment with 1 1
HC1 and reagents is only required occasionally Commercial detergent should never be
used
Reagents
7 1 Sulfuric acid solution, 5N Slowly add 70 ml of cone H2SO4 to approximately 400 ml of
distilled water Cool to room temperature and dilute to 500 ml with distilled water
7 2 Antimony potassium tartrate solution Weigh 0 3 g K(SbO)C4H4O6»l/2H2O, dissolve in
50 ml distilled water in 100 ml volumetric flask, dilute to volume Store at 4°C in a dark,
glass-stoppered bottle
7 3 Ammonium molybdate solution Dissolve 4 g (NH4)6Mo7O24»4H2O in 100 ml distilled
water Store in a plastic bottle at 4°C
7 4 Ascorbic acid, 0 1M Dissolve 1 8 g of ascorbic acid in 100 ml of distilled water The
solution is stable for about a week if prepared with water containing no more than trace
amounts of heavy metals and stored at 4°C
7.5 Combined reagent (AAI) Mix the above reagents in the following proportions for 100 ml
of the mixed reagent 50 ml of 5N H2SO4 (7 1), 5 ml of antimony potassium tartrate
solution (7 2), 15 ml of ammonium molybdate solution (7 3), and 30 ml of ascorbic acid
solution (7 4) Mix after addition of each reagent All reagents must reach room
temperature before they are mixed and must be mixed in the order given If turbidity
forms in the combined reagent, shake and let stand for a few minutes until the turbidity
disappears before processing This volume is sufficient for 4 hours operation Since the
stability of this solution is limited, it must be freshly prepared for each run,
NOTE 1: A stable solution can be prepared by not including the ascorbic acid in the
combined reagent If this is done, the mixed reagent (molybdate, tartrate, and acid) is
pumped through the distilled water line and the ascorbic acid solution (30 ml of 7 4
diluted to 100 ml with distilled water) through the original mixed reagent line
7 6 Sulfuric acid solution, 11 N Slowly add 310 ml cone H2SO4 to 600 ml distilled water
When cool, dilute to 1 liter
365 1-4
-------
7 7 Ammonium persulfate
7 8 Acid wash water Add 40 ml of sulfuric acid solution (7 6) to 1 liter of distilled water and
dilute to 2 liters (Not to be used when only orthophosphate is being determined)
7 9 Phenolphthalem indicator solution (5 g/1) Dissolve 0 5 g of phenolphthalem in a
solution of 50 ml of ethyl or isopropyl alcohol and 50 ml of distilled water
7 10 Stock phosphorus solution Dissolve 0 4393 g of pre-dned (105°C for 1 hour) KH2PO4 m
distilled water and dilute to 1000 ml 1 0 ml = 0 1 mg P
7 11 Standard phosphorus solution Dilute 100 0 ml of stock solution (7 10) to 1000 ml with
distilled water 1 0 ml = 0 01 mg P
7 12 Standard phosphorus solution Dilute 100 0 ml of standard solution (7 11) to 1000 ml
with distilled water 1 0 ml = 0 001 mg P
713 Prepare a series of standards by diluting suitable volumes of standard solutions (7 11)
and (7 12) to 100 0 ml with distilled water The following dilutions are suggested
ml of Standard Cone ,
Phosphorus Solution (7 12) mg P/l
00 000
20 002
50 005
100 010
ml of Standard
Phosphorus Solution (7 11) mg P/l
20 020
50 050
80 080
100 100
Procedure
8 1 Phosphorus
811 Add 1 ml of sulfuric acid solution (7 6) to a 50 ml sample and/or standard m a 125
ml Erlenmeyer flask
812 Add 0 4 g of ammonium persulfate
813 Boil gently on a pre-heated hot plate for approximately 30-40 minutes or until a
final volume of about 10 ml is reached Do not allow sample to go to dryness
Alternately, heat for 30 minutes m an autoclave at 121°C (15-20 psi)
814 Cool and dilute the sample to 50 ml If sample is not clear at this point, filter
815 Determine phosphorus as outlined in (8 3 2) with acid wash water (7 8) m wash
tubes
82 Hydrolyzable Phosphorus
821 Add 1 ml of sulfuric acid solution (7 6) to a 50 ml sample and/or standard in a 125
ml Erlenmeyer flask
365 1-5
-------
822 Boil gently on a pre-heated hot plate for 30-40 minutes or until a final volume of
about 10 ml is reached Do not allow sample to go to dryness Alternatively, heat
for 30 minutes in an autoclave at 121°C (15-20 psi)
823 Cool and dilute the sample to 50 ml If sample is not clear at this point, filter
824 Determine phosphorus as outlined m (8 3 2) with acid wash water (7 8) in wash
tubes
8 3 Orthophosphate
831 Add 1 drop of phenolphthalem indicator solution (7 9) to approximately 50 ml of
sample If a red color develops, add sulfunc acid solution (7 6) drop-wise to just
discharge the color Acid samples must be neutralized with 1 N sodium hydroxide
(40gNaOH/l)
832 Set up manifold as shown in Figure 2, AAI or Figure 3, AAII
833 Allow both colorimeter and recorder to warm up for 30 minutes Obtain a stable
baseline with all reagents, feeding distilled water through the sample line
834 For the AAI system, sample at a rate of 20/hr, 1 minute sample, 2 minute wash
For the AAII system, use a 30/hr, 2 1 cam, and a common wash
835 Place standards in Sampler in order of decreasing concentration Complete filling
of sampler tray with unknown samples
836 Switch sample line from distilled water to Sampler and begin analysis
9 Calculation
9 1 Prepare a standard curve by plotting peak heights of processed standards against known
concentrations Compute concentrations of samples by comparing sample peak heights
with standard curve Any sample whose computed value is less than 5% of its immediate
predecessor must be rerun
10 Precision and Accuracy (AAI system)
10 1 Six laboratories participating in an EPA Method Study, analyzed four natural water
samples containing exact increments of Orthophosphate, with the following results
Increment as
Orthophosphate
rag P/liter
004
004
029
030
Precision as
Standard Deviation
mg P/liter
0019
0014
0087
0066
Accuracy as
Bias,
%
+ 167
- 83
-155
-128
Bias,
mg P/liter
+0007
-0003
-005
-004
10 2 In a single laboratory (EMSL), using surface water samples at concentrations of 0 04,
0 19, 035, and 0 84 mg P/l, standard deviations were ±0005, ±0000, ±0003, and
±Q 000, respectively
10 3 In a single laboratory (EMSL), using surface water samples at concentrations of 0 07 and
0 76 mg p/1, recoveries were 99% and 100%, respectively
365 1-6
-------
Bibliography
1 Murphy, J and Riley, J , "A Modified Single Solution for the Determination of Phosphate in
Natural Waters" Anal China Acta ,27, 31 (1962)
2 Gales, M , Jr , Julian, E , and Kroner, R , "Method for Quantitative Determination of Total
Phosphorus in Water" Jour AWWA, 58, No 10,1363(1966)
3 Lobrmg, L B and Booth, R L , "Evaluation of the AutoAnalyzer II; A Progress Report",
Techmcon International Symposium, June, 1972 New York, N Y
4 Annual Book of ASTM Standards, Part 31, "Water", Standard D515-72, p 388 (1976)
5 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 624,
Method 606, (1975)
365 1-7
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365 1-8
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365 1-9
-------
PHOSPHORUS, ALL FORMS
Method 365.2 (Colorimetric, Ascorbic Acid, Single Reagent)
STORET NO. See Section 4
1 Scope and Application
1 1 These methods cover the determination of specified forms of phosphorus m drinking,
surface and saline waters, domestic and industrial wastes
1 2 The methods are based on reactions that are specific for the orthophosphate ion Thus,
depending on the prescribed pre-treatment of the sample, the various forms of
phosphorus given in Figure 1 may be determined These forms are defined in Section 4
121 Except for in-depth and detailed studies, the most commonly measured forms are
phosphorus and dissolved phosphorus, and orthophosphate and dissolved
orthophosphate Hydrolyzable phosphorus is normally found only m sewage-type
samples and insoluble forms of phosphorus are determined by calculation
1 3 The methods are usable in the 0 01 to 0 5 mg P/l range
2 Summary of Method
2 1 Ammonium molybdate and antimony potassium tartrate react in an acid medium with
dilute solutions of phosphorus to form an antimony-phospho-molybdate complex This
complex is reduced to an intensely blue-colored complex by ascorbic acid The color is
proportional to the phosphorus concentration
2 2 Only orthophosphate forms a blue color in this test Polyphosphates (and some organic
phosphorus compounds) may be converted to the orthophosphate form by sulfunc acid
hydrolysis Organic phosphorus compounds may be converted to the orthophosphate
form by persulfate digestion®
3 Sample Handling and Preservation
31 If benthic deposits are present in the area being sampled, great care should be taken not
to include these deposits
3 2 Sample containers may be of plastic material, such as cubitamers, or of Pyrex glass
33 If the analysis cannot be performed the day of collection, the sample should be preserved
by the addition of 2 ml cone H2SO4 per liter and refrigeration at 4°C
4 Definitions and Storet Numbers
4 1 Total Phosphorus (P) — all of the phosphorus present in the sample, regardless of form,
as measured by the persulfate digestion procedure (00665)
4 1 1 Total Orthophosphate (P, ortho) — inorganic phosphorus [(PO4)"3] in the sample
as measured by the direct colorimetnc analysis procedure (70507)
412 Total Hydrolyzable Phosphorus (P, hydro) - phosphorus in the sample as
measured by the sulfuric acid hydrolysis procedure, and minus pre-determmed
orthophosphates This hydrolyzable phosphorus includes polyphosphorus
[(PsO?)"4, (P3O10)"5, etc ] plus some organic phosphorus (00669)
Approved for NPDES
Issued 1971
365 2-1
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413 Total Organic Phosphorus (P, org) — phosphorus (inorganic plus oxidizable
organic) in the sample measured by the persulfate digestion procedure, and minus
hydrolyzable phosphorus and orthophosphate (00670)
4 2 Dissolved Phosphorus (P-D) — all of the phosphorus present in the filtrate of a sample
filtered through a phosphorus-free filter of 0 45 micron pore size and measured by the
persulfate digestion procedure (00666)
421 Dissolved Orthophosphate (P-D, ortho) — as measured by the direct colonmetnc
analysis procedure (00671)
422 Dissolved Hydrolyzable Phosphorus (P-D, hydro) — as measured by the sulfunc
acid hydrolysis procedure and minus pre-determmed dissolved orthophosphates
(00672)
423 Dissolved Organic Phosphorus (P-D, org) — as measured by the persulfate
digestion procedure, and minus dissolved hydrolyzable phosphorus and
orthophosphate (00673)
4 3 The following forms, when sufficient amounts of phosphorus are present in the sample to
warrant such consideration, may be calculated
43 1 Insoluble Phosphorus (P-I)=(P)-(P-D) (00667)
4311 Insoluble orthophosphate (P-I, ortho)=(P, ortho)-(P-D, ortho)
(00674)
4312 Insoluble Hydrolyzable Phosphorus (P-I, hydro)=(P, hydro)-(P-D,
hydro) (00675)
4313 Insoluble Organic Phosphorus (P-I, org)=(P, org) - (P-D, org)
(00676)
4 4 All phosphorus forms shall be reported as P, mg/1, to the third place
Interferences
51 No interference is caused by copper, iron, or silicate at concentrations many times
greater than their reported concentration in sea water However, high iron
concentrations can cause precipitation of and subsequent loss of phosphorus
5 2 The salt error for samples ranging from 5 to 20% salt content was found to be less than
1%
5 3 Arsenate is determined similarly to phosphorus and should be considered when present
m concentrations higher than phosphorus However, at concentrations found in sea
water, it does not interfere
Apparatus
6 1 Photometer - A spectrophotometer or filter photometer suitable for measurements at
650 or 880 nm with a light path of 1 cm or longer
6 2 Acid-washed glassware All glassware used should be washed with hot 1 1 HC1 and
rinsed with distilled water The acid-washed glassware should be filled with distilled
water and treated with all the reagents to remove the last traces of phosphorus that might
be adsorbed on the glassware Preferably, this glassware should be used only for the
determination of phosphorus and after use it should be rinsed with distilled water and
365 2-3
-------
kept covered until needed again If this is done, the treatment with 1 1 HC1 and reagents
is only required occasionally Commercial detergents should never be used
7. Reagents
7 1 Sulfunc acid solution, 5N Dilute 70 ml of cone H2SO4 with distilled water to 500 ml
7 2 Antimony potassium tartrate solution Weigh 1 3715 g K(SbO)C4H4O6«l/2H2O,
dissolve in 400 ml distilled water in 500 ml volumetric flask, dilute to volume Store at
4°C m a dark, glass-stoppered bottle
7 3 Ammonium molybdate solution Dissolve 20 g(NH4)6Mo7O24«4H2O in 500 ml of distilled
water Store m a plastic bottle at 4°C
7 4 Ascorbic acid, 0 LM Dissolve 1 76 g of ascorbic acid in 100 ml of distilled water The
solution is stable for about a week if stored at 4°C
7 5 Combined reagent Mix the above reagents in the following proportions for 100 ml of the
mixed reagent 50 ml of 5N H2SO4) (7 1), 5 ml of antimony potassium tartrate solution
(7 2), 15 ml of ammonium molybdate solution (7 3), and 30 ml of ascorbic acid solution
(7 4) Mix after addition of each reagent All reagents must reach room temperature
before they are mixed and must be mixed m the order given If turbidity forms m the
combined reagent, shake and let stand for a few minutes until the turbidity disappears
before proceeding Since the stability of this solution is limited, it must be freshly
prepared for each run
7 6 Sulfunc acid solution, 11 N Slowly add 310 ml cone H2SO4 to 600 ml distilled water
When cool, dilute to 1 liter
7 7 Ammonium persulfate
7 8 Stock phosphorus solution Dissolve in distilled water 0 2197 g of potassium dihydrogen
phosphate, KH2PO4, which has been dried in an oven at 105°C Dilute the solution to
1000ml, 1 Oml = 005 mgP
7 9 Standard phosphorus solution Dilute 10 0 ml of stock phosphorus solution (7 8) to 1000
ml with distilled water, 1 0 ml = 0 5 ug P
791 Using standard solution, prepare the following standards in 50 0 ml volumetric
flasks
ml of Standard
Phosphorus Solution (79) Cone, mg/1
0 000
10 001
30 003
50 005
100 010
20 0 0 20
30 0 0 30
40 0 0 40
50 0 0 50
7 10 Sodium hydroxide, 1 N Dissolve 40 g NaOH in 600 ml distilled water Cool and dilute
to 1 liter
365 2-4
-------
Procedure
8 1 Phosphorus
8 1 1 Add 1 ml of H2SO4 solution (7 6) to a 50 ml sample in a 125 ml Erlenmeyer flask
812 Add 0 4 g of ammonium persulfate
8 1 3 Boil gently on a pre-heated hot plate for approximately 30-40 minutes or until a
final volume of about 10 ml is reached Do not allow sample to go to dryness
Alternatively, heat for 30 minutes in an autoclave at 121°C (15-20 psi)
8 1 4 Cool and dilute the sample to about 30 ml and adjust the pH of the sample to 7 0
+0 2 with 1 N NaOH (7 10) using a pH meter If sample is not clear at this point,
add 2-3 drops of acid (7 6) and filter Dilute to 50 ml
Alternatively, if autoclaved see NOTE 1
8 1 5 Determine phosphorus as outlined in 8 3 2 Orthophosphate
8 2 Hydrolyzable Phosphorus
8 2 1 Add 1 ml of H2SO4 solution (7 6) to a 50 ml sample in a 125 ml Erlenmeyer flask
822 Boil gently on a pre-heated hot plate for 30-40 minutes or until a final volume of
about 10 ml is reached Do not allow sample to go to dryness Alternatively, heat
for 30 minutes in an autoclave at 121°C (15-20 psi)
823 Cool and dilute the sample to about 30 ml and adjust the pH of the sample to 7 0
±0 2 with NaOH (7 10) using a pH meter If sample is not clear at this point, add
2-3 drops of acid (7 6) and filter Dilute to 50 ml
Alternatively, if autoclaved see NOTE 1
824 The sample is now ready for determination of phosphorus as outlined in 8 3 2
Orthophosphate
8 3 Orthophosphate
8 3 1 The pH of the sample must be adjusted to 7±0 2 using a pH meter
832 Add 8 0 ml of combined reagent (7 5) to sample and mix thoroughly After a
minimum of ten minutes, but no longer than thirty minutes, measure the color
absorbance of each sample at 650 or 880 nm with a spectrophotometer, using the
reagent blank as the reference solution
NOTE 1: If the same volume of sodium hydroxide solution is not used to adjust the
pH of the standards and samples, a volume correction has to be employed
Calculation
9 1 Prepare a standard curve by plotting the absorbance values of standards versus the
corresponding phosphorus concentrations
9 1 1 Process standards and blank exactly as the samples Run at least a blank and two
standards with each series of samples If the standards do not agree within ±2% of
the true value, prepare a new calibration curve
9 2 Obtain concentration value of sample directly from prepared standard curve Report
results as P, mg/1 SEE NOTE 1.
365 2-5
-------
10 Precision and Accuracy
10 1 Thirty-three analysts in nineteen laboratories analyzed natural water samples containing
exact increments of organic phosphate, with the following results
Increment as
Total Phosphorus
mg P/liter
0110
0132
0772
0882
Precision as
Standard Deviation
mg P/liter
0033
0051
0130
0128
Accuracy as
Bias,
+ 309
+ 1199
+296
-092
Bias
mg P/hter
+0003
+0016
+0023
-0008
(FWPCA Method Study 2, Nutrient Analyses)
10 2 Twenty-six analysts m sixteen laboratories analyzed natural water samples containing
exact increments of orthophosphate, with the following results
Increment as
Orthophosphate
mg P/liter
0029
0038
0335
0383
Precision as
Standard Deviation
mg P/liter
0010
0008
0018
0023
Bias,
-495
-600
-275
-176
Accuracy as
"Has;
mg P/liter
-0001
-0002
-0009
-0007
(FWPCA Method Study 2, Nutrient Analyses)
Bibliography
1
Murphy, J, and Riley, J , "A modified Single Solution for the Determination of Phosphate in
Natural Waters", Anal Chim Acta, 27, 31 (1962)
2. Gales, M , Jr, Julian, E, and Kroner, R , "Method for Quantitative Determination of Total
Phosphorus in Water", Jour AWWA,58,No 10,1363(1966)
3. Annual Book of ASTM Standards, Part 31, "Water", Standard D515-72, Method A, p 389
(1976)
4 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 476 and 481
(1975)
365 2-6
-------
PHOSPHORUS, ALL FORMS
Method 365.3 (Colorimetric, Ascorbic Acid, Two Reagent)
STORET NO. See Section 4
1 Scope and Application
1 1 These methods cover the determination of specified forms of phosphorus in drinking,
surface and saline waters, domestic and industrial wastes
1 2 The methods are based on reactions that are specific for the orthophosphate ion Thus,
depending on the prescribed pretreatment of the sample, the various forms may be
determined
121 Except for in-depth and detailed studies, the most commonly measured forms are
phosphorus and dissolved phosphorus, and orthophosphate and dissolved
orthophosphate Hydrolyzable phosphorus is normally found only in sewage-type
samples and insoluble forms of phosphorus are determined by calculation
1 3 The methods are usable in the 0 01 to 1 2 mg P/1 range
2 Summary of Method
2 1 Ammonium molybdate and antimony potassium tartrate react in an acid medium with
dilute solutions of phosphorus to form an antimony-phospho-molybdate complex This
complex is reduced to an intensely blue-colored complex by ascorbic acid The color is
proportional to the phosphorus, concentration
2 2 Only orthophosphate forms a blue color in this test Polyphosphates (and some organic
phosphorus compounds) may be converted to the orthophosphate form by sulfunc-acid-
hydrolysis Organic phosphorus compounds may be converted to the orthophosphate
form by persulfate digestion
3 Sample Handling and Preservation
3 1 If benthic deposits are present in the area being sampled, great care should be taken not
to include these deposits
3 2 Sample containers may be of plastic material, such as cubitamers, or of Pyrex glass
33 If the analysis cannot be performed the day of collection, the sample should be preserved
by the addition of 2 ml cone H2SO4 per liter and refrigeration at 4°C
4 Definitions and Storet Numbers
4 1 Total Phosphorus (P) — all of the phosphorus present in the sample, regardless of form,
as measured by the persulfate digestion procedure (00665)
411 Total Orthophosphate (P, ortho) — inorganic phosphorus [(PO4)~3] in the sample
as measured by the direct colonmetnc analysis procedure (70507)
412 Total Hydrolyzable Phosphorus (P, hydro) - phosphorus in the sample as
measured by the sulfunc acid hydrolysis procedure, and minus pre-determmed
orthophosphates This hydrolyzable phosphorus includes polyphosphorus
[(PzOy)"4, (P3O10)"5, etc ] plus some organic phosphorus (00669)
Approved for NPDES
Issued 1978
365 3-1
-------
413 Total Organic Phosphorus (P, org) — phosphorus (inorganic plus oxidizable
organic) in the sample measured by the persulfate digestion procedure, and minus
hydrolyzable phosphorus and orthophosphate (00670)
4 2 Dissolved Phosphorus (P-D) — all of the phosphorus present m the filtrate of a sample
filtered through a phosphorus-free filter of 0 45 micron pore size and measured by the
persulfate digestion procedure (00666)
4 2 1 Dissolved Orthophosphate (P-D, ortho) — as measured by the direct colonmetnc
analysis procedure (00671)
422 Dissolved Hydrolyzable Phosphorus (P-D, hydro) — as measured by the sulfunc
acid hydrolysis procedure and minus pre-determmed dissolved orthophosphates
(00672)
423 Dissolved Organic Phosphorus (P-D, org) — as measured by the persulfate
digestion procedure, and minus dissolved hydrolyzable phosphorus and
orthophosphate (00673)
4 3 The following forms, when sufficient amounts of phosphorus are present in the sample to
warrant such consideration, may be calculated
4.31 Insoluble Phosphorus (P-I)=(P)-(P-D) (00667)
4311 Insoluble orthophosphate (P-I, ortho) = (P, ortho) - (P-D, ortho)
(00674)
4312 Insoluble Hydrolyzable Phosphorus (P-I, hydro)=(P, hydro) - (P-D,
hydro) (00675)
4313 Insoluble Organic Phosphorus (P-I, org) = (P, org) - (P-D, org)
(00676)
44 All phosphorus forms shall be reported as P, mg/1, to the third place
5. Interferences
5.1 Arsenate is determined similanly to phosphorus and should be considered when present
This interference may be eliminated by reducing the arsenic acid to arsemous acid with
sodium bisulfite (7 4)
5 2 When high concentrations of iron are present low recovery of phosphorus will be
obtained because it will use some of the reducing agent The bisulfite treatment will also
eliminate this interference
6. Apparatus
6.1 Photometer-A spectrophotometer or filter photometer suitable for measurements at 660
or 880 nm with a light path of 1 cm or longer
6 2 Acid-washed glassware All glassware used should be washed with hot 1 1 HC1 and
nnsed with distilled water The acid-washed glassware should be filled with distilled
water and treated with all the reagents to remove the last traces of phosphorus that might
be absorbed on the glassware Preferably, this glassware should be used only for the
determination of phosphorus and after use it should be rinsed with distilled water and
kept covered until needed again If this is done, the treatment with 1 1 HC1 and reagents
is only required occasionally Commercial detergents should never be used
6.3 Water bath, 95°C
365 3-2
-------
Reagents
7 1 Ammonium molybdate-antimony potassium tartrate solution Dissolve 8 g of
ammonium molybdate and 0 2 g antimony potassium tartrate in 800 ml of distilled water
and dilute to 1 liter
7 2 Ascorbic acid solution Dissolve 60 g of ascorbic acid in 800 ml of distilled water and
dilute to 1 liter Add 2 ml of acetone This solution is stable for two weeks
7 3 Sulfunc acid, 11 N Slowly add 310 ml of cone H2SO4 to approximately 600 ml distilled
water Cool and dilute to 1000 ml
7 4 Sodium bisulfite (NaHSO3) solution Dissolve 5 2 g of NaHSO3 in 100 ml of 1 0 N
H2S04
7 5 Ammonium persulfate
7 6 Stock phosphorus solution Dissolve 0 4393 g of predned (105°C for one hour) KH2PO4
in distilled water and dilute to 1000 ml 1 0 ml = 0 1 mg P
7 7 Standard phosphorus solution Dilute 100 ml of stock phosphorus solution to 1000 ml
with distilled water 10ml = 001mgP Prepare an appropriate series of standards by
diluting suitable volumes of standard or stock solutions to 100 ml with distilled water
Procedure
8 1 Total Phosphorus
8 1 1 Transfer 50 ml of sample or an aliquot diluted to 50 ml into a 125 ml Erlenmeyer
flask and add 1 ml of 11 N sulfunc acid (7 3)
812 Add 0 4 g ammonium persulfate (7 5), mix and boil gently for approximately
30-40 minutes or until a final volume of about 10 ml is reached Alternatively heat
for 30 minutes in an autoclave at 121°C (15-20 psi) Cool, dilute to approximately
40 ml and filter
813 For samples containing arsenic or high levels of iron, add 5 ml of sodium bisulfite
(7 4), mix and place in a 95°C water bath for 30 minutes (20 minutes after the
temperature of the sample reaches 95°C) Cool and dilute to 50 ml
814 Determine phosphorus as outlined in (8 3) orthophosphate
8 2 Hydrolyzable Phosphorus
821 Add 1 ml of H2SO4 solution (8 3) to a 50 ml sample in a 125 ml Erlenmeyer flask
822 Boil gently on a pre-heated hot plate for 30-40 minutes or until a final volume of
about 10 ml is reached Do not allow sample to go to dryness Alternatively, heat
for 30 minutes in an autoclave at 121°C (15-20 psi) Cool, dilute to approximately
40 ml and filter
823 Treat the samples as in 8 1 3
824 Determine phosphorus as outlined in (8 3) orthophosphate
8 3 Orthophosphate
831 To 50 ml of sample and/or standards, add 1 ml of 11 N sulfunc acid (7 3) and 4 ml
of ammonium molybdate-antimony potassium tartrate (7 1) and mix
NOTE: If sample has been digested for total or hydrolyzable phosphorus do not
add acid
832 Add 2 ml of ascorbic acid solution (7 2) and mix
365 3-3
-------
833 After 5 minutes, measure the absorbance at 650 run with a spectrophotometer and
determine the phosphorus concentration from the standard curve The color is
stable for at least one hour For concentrations in the range of 0 01 to 0 3 mg P/l, a
5 cm cell should be used A one cm cell should be used for concentrations in the
range of 0 3 to 1 2 mg P/l
9 Calculation
9 1 Prepare a standard curve by plotting the absorbance values of standards versus the
corresponding phosphorus concentrations on linear graph paper
9 2 Obtain concentration value of sample directly from prepared standard curve Report
results as P, mg/1
10 Precision and Accuracy
10 1 Precision data is not available at this time
102 In a single laboratory (EMSL) using industrial waste and sewage samples at
concentrations of 7 6 and 0 55 mg P/l, recoveries were 99 and 100%, respectively
365 3-4
-------
PHOSPHORUS, TOTAL
Method 365.4 (Colorimetric, Automated, Block Digester AA II)
STORET NO. 00665
1 Scope and Application
1 1 This method covers the determination of total phosphorus in drinking water, surface
water and domestic and industrial wastes The applicable range of this method is 0 01 to
20mgP/l
2 Summary of Method
2 1 The sample is heated in the presence of sulfunc acid, K2SO4 and HgSO4 for two and one
half hours The residue is cooled, diluted to 25 ml and placed on the AutoAnalyzer for
phosphorus determination
3 Sample Handling and Preservation
3 1 Sample containers may be of plastic material, such as a cubitainer, or of Pyrex glass
32 If the analysis cannot be performed the day of collection, the sample should be preserved
by the addition of 2 ml of cone H2SO4 per liter and refrigeration at 4°C
4 Apparatus
4 1 Block Digestor BD-40
42 Techmcon Method No 327-74W for Phosphorus
5 Reagents
5 1 Mercuric sulfate Dissolve 8 g red mercuric oxide (HgO) in 50 ml of 1 4 sulfunc acid
(10 cone H2SO4 40 ml distilled water) and dilute to 100 ml with distilled water
5 2 Digestion solution (Sulfunc acid-mercunc sulfate-potassium sulfate solution) Dissolve
133 g of K2SO4 in 600 ml of distilled water and 200 ml of cone H2SO4 Add 25 ml of
mercunc svlfate solution (5 1) and dilute to 1 liter
5 3 Sulfunc acid solution (0 72 N) Add 20 ml of cone sulfunc acid to 800 of distilled water,
mix and dilute to 1 liter
5 4 Molybdate/antimony solution Dissolve 8 g of ammonium molybdate and 0 2 g of
antimony potassium tartrate m about 800 ml of distilled water and dilute to 1 liter
5 5 Ascorbic acid solution Dissolve 60 g of ascorbic acid in about 600 ml of distilled water
Add 2 ml of acetone and dilute to 1 liter
5 6 Diluent water Dissolve 40 g of Nad in about 600 ml of distilled water and dilute to 1
liter
5 7 Sulfunc acid solution, 4% Add 40 ml of cone sulfunc acid to 800 ml of ammonia-free
distilled water, cool and dilute to 1 liter
6 Procedure
Digestion
61 To 20 or 25 ml of sample, add 5 ml of digestion solution and mix (Use a vortex mixer)
6 2 Add 4-8 Teflon boiling chips Too many boiling chips will cause the sample to boil over
Pending approval for NPDES and Section 304(h), CWA
Issued 1974
3654-1
-------
6 3 With Block Digester in manual mode set low and high temperature at 160°C and preheat
unit to 160°C Place tubes m digester and switch to automatic mode Set low temperature
timer for 1 hour Reset high temperature to 380°C and set timer for 21/2 hours
6 4 Cool sample and dilute to 25 ml with distilled water If TKN is determined the sample
should be diluted with ammonia-free water
Colonmetnc Analysis
641 Check the level of all reagent containers to ensure an adequate supply
642 Excluding the molybdate/antimony line, place all reagent lines in their respective
containers, connect the sample probe to the Sampler IV and start the proportioning
pump
643 Flush the Sampler IV wash receptacle with about 25 ml of 4% sulfunc acid (5 7)
644 When reagents have been pumping for at least five minutes, place the
molybdate/antimony line in its container and allow the system to equilibrate
645 After a stable baseline has been obtained, start the sampler
7 Calculations
7 1 Prepare a standard curve by plotting peak heights of processed standards against
concentration values Compute concentrations by comparing sample peak heights with
the standard curve
8. Precision and Accuracy
81 In a single laboratory (EMSL) using sewage sample containing total P at levels of 0 23,
1 33, and 2 0, the precision was ±001, ±004, and ±0 06, respectively
82 In a single laboratory (EMSL) using sewage samples of concentration 1 84 and 1 89, the
recoveries were 95 and 98%, respectively
Bibliography
1 McDamel, W H , Hemphill, R N and Donaldson, W T, "Automatic Determination of Total
Kjeldahl Nitrogen in Estuarme Water", Techmcon Symposia, pp 362-367, Vol 1,1967
2 Gales, M.E and Booth, R L , "Evaluation of Organic Nitrogen Methods", EPA Office of
Research and Monitoring, June, 1972
3 Gales, ME and Booth, RL, "Simultaneous and Automated Determination of Total
Phosphorus and Total Kjeldahl Nitrogen", Methods Development and Quality Assurance
Research Laboratory, May, 1974
4. Techmcon "Total Kjeldahl Nitrogen and Total Phosphorus BD-40 Digestion Procedure for
Water", August, 1974
5 Gales, M E, and Booth, R L, "Evaluation of the Techmcon Block Digestor System for the
Measurement of Total Kjeldahl Nitrogen and Total Phosphorus", EPA-600 /4-78-015,
Environmental Monitoring and Support Laboratory, Cincinnati, Ohio
365 4-2
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SILICA, DISSOLVED
Method 370.1 (Colorimetric)
STORET NO. Dissolved 00955
1 Scope and Application
1 1 This method is applicable to drinking, surface and saline waters, domestic and industrial
wastes
1 2 The working range of the method is approximately 2 to 25 mg silica/1 The upper range
can be extended by taking suitable ahquots, the lower range can be extended by the
addition of ammo-naphthol-sulfonic acid solution, as described in (6 8)
2 Summary of Method
21 A well-mixed sample is filtered through a 0 45 u membrane filter The filtrate, upon the
addition of molybdate ion m acidic solution, forms a greenish-yellow color complex
proportional to the dissolved silica in the sample The color complex is then measured
spectrophotometncally
22 In the low concentration modification the yellow (410 nm) molybdosihcic acid color is
reduced by l-amino-2-naphthol-4-sulfomc acid to a more intense heteropoly blue (815
nm or 650 nm)
3 Interferences
3 1 Excessive color and/or turbidity interfere Correct by running blanks prepared without
addition of the ammonium molybdate solution See (6 7)
3 2 Tannin interference may be eliminated and phosphate interferences may be decreased
with oxalic acid
3 3 Large amounts of iron and sulfide interfere
3 4 Contact with glass should be minimized, silica free reagents should be used as much as
possible A blank should be run
4 Apparatus
4 1 Platinum dishes, 100 ml
4 2 Colorimetric equipment-one of the following
421 Spectrophotometer for use at 410 nm, 650 nm and/or 815 nm with a 1 cm or longer
cell
422 Filter photometer with a violet filter having maximum transmittance as near 410
nm as possible and a 1 cm or longer cell
423 Nessler tubes, matched, 50 ml, tall form
5 Reagents
5 1 Use chemicals low m silica and store in plastic containers
5 2 Sodium bicarbonate, NaHCO3, powder
5 3 Sulfunc acid, H2SO4, 1 N_
Approved for NPDES
Issued 1971
Editorial revision 1978
370 1-1
-------
5 4 Hydrochloric acid, HC1,1 + 1
5 5 Ammonium molybdate reagent Place 10 g (NH4)6Mo7O24»4H2O m distilled water in a
100 ml volumetric Dissolve by stirring and gently warming Dilute to the mark Filter if
necessary Adjust to pH 7 to 8 with silica free NH4OH or NaOH Store in plastic bottle
5 6 Oxalic acid solution Dissolve 10 g H2C2O4»2H2O m distilled water in a 100 ml
volumetric flask, dilute to the mark Store m plastic
5 7 Stock silica solution Dissolve 4 73 g sodium metasilicate nonahydrate, Na2SiO3»9H2O,
in recently boiled and cooled distilled water Dilute to approximately 900 ml Analyze
100 0 ml portions by gravimetry (ref 1, p 484) Adjust concentration to 1 000 mg/1
SiO2 Store m tightly stoppered plastic bottle
5.8 Standard silica solution Dilute 10 0 ml stock solution to 1 liter with recently boiled and
cooled distilled water This is 10 mg/1 SiO2 (1 00 ml = 10 0 ug SiO2) Store m a tightly
stoppered plastic bottle
5.9 Permanent color solutions
591 Potassium chromate solution Dissolve 630 mg K2CrO4 in distilled water m a 1
liter volumetric flask and dilute to the mark
'592 Borax solution Dissolve 10 g sodium borate decahydrate, (Na2B4O7«10H2O) m
distilled water in a 1 liter volumetric flask and dilute to the mark
5.10 Reducing agent Dissolve 500 mg of l-amino-2-naphthol-4-sulfonic acid and 1 g Na2SO3
m 50 ml distilled water with gentle warming if necessary Dissolve 30 g NaHSO3 in 150
ml distilled water Mix these two solutions Filter into a plastic bottle Refrigerate and
avoid exposure to light Discard when it darkens If there is incomplete solubility or
immediate darkening of the ammonaphthosulfonic acid solution do not use
Procedure
6 1 Filter sample through a 0 45 u membrane filter
6 2 Digestion If molybdate unreactive silica is present and its inclusion m the analysis is
desired, include this step, otherwise proceed to 6 3
621 Place 50 ml, or a smaller portion diluted to 50 ml, of filtered (61) sample m a 100
ml platinum dish
622 Add 200 mg silica-free NaHCO3 (5 2) and digest on a steam bath for 1 hour Cool
623 Add slowly and with stirring 2 4 ml H2SO4 (5 3)
624 Immediately transfer to a 50 ml Nessler tube, dilute to the mark with distilled
water and proceed to 6 3 without delay
6 3 Color development
631 Place 50 ml sample in a Nessler tube
632 Add rapidly 1 0 ml of 1 +1 HC1 (5 4) and 2 0 ml ammonium molybdate reagent
(55)
633 Mix by inverting at least 6 times
634 Let stand 5 to 10 minutes
635 Add 1 5 ml oxalic acid solution (5 6) and mix thoroughly
636 Read color (spectrophotometncally or visually) after 2 minutes but before 15
minutes from the addition of oxalic acid
370 1-2
-------
6 4 Preparation of Standards
6 4 1 If digestion (6 2) was used add 200 mg NaHCO3 (5 2) and 2 4 ml H2SO4 (5 3) to
standards to compensate for silica introduced by these reagents and for effect of the
salt on the color intensity
6 5 Photometric measurement
651 Prepare a calibration curve using approximately six standards to span the range
shown below with the selected light path
Selection of Light Path Length for Various
Silica Concentrations
66
Light Path
cm
1
2
5
10
Silica in 54 5 ml
final volume (ug)
200-1300
100-700
40-250
20-130
652 Carry out the steps in 6 3 using distilled water as the reference Read a blank
653 Plot photometric reading versus ug of silica in the final solution of 54 5 nil Run a
reagent blank and at least one standard with each group of samples
Visual Comparison
6 6 1 Prepare a set of permanent artificial color standards according to the table Use
well stoppered, properly labelled 50 ml Nessler tubes
Potassium
chromate
solution
(5 9 1) ml
00
10
20
40
50
75
100
Borax
solution
(5 9 2) ml
25
25
25
25
25
25
25
Distilled
water
ml
30
29
28
26
25
22
20
662 Verify permanent standards by comparison to color developed by standard silica
solutions
663 These permanent artificial color standards are only for color comparison
procedure, not for photometric procedure
Correction for color or turbidity
6 7 1 A special blank is run using a portion of the sample and carrying out the procedure
in 6 1, 6 2 if used, and 6 3 except for the addition of ammonium molybdate ^6 3 2)
370 1-3
-------
672 Zero the photometer with this blank before reading the samples
6.8 Procedure for low concentration ( < 1000 ug/1)
681 Perform steps 6 1 and 6 2 if needed
682 Place 50 ml sample in a Nessler tube
6 8 3 In rapid succession add 1 0 ml of 1 +1 HC1 (5 4)
684 Add 2 0 ml ammonium molybdate reagent (5 5)
685 Mix by inverting at least six times
6.8 6 Let stand 5 to 10 minutes
687 Add 1 5 ml oxalic acid solution (5 6)
6 8.8 Mix thoroughly
6 8.9 At least 2, but not more than 15 minutes after oxalic acid addition, add 2 0 ml
reducing agent (5 10)
6 8 10 Mix thoroughly
6811 Wait 5 minutes, read photometrically or visually
6 8 12 If digestion (6 2) was used see (6 4)
6813 Photometric measurement
6 8 13 1 Prepare a calibration curve using approximately 6 standards and a
reagent blank to span the range shown below with the selected light
path
Selection of Light Path Length for
Various Silica Concentrations
Light Path Silica in 56 5 ml Final volume, ug
°!S 650 nm 815 nm
1 40-300 20-100
2 20-150 10-50
5 7-50 4-20
10 4-30 2-10
68132 Read versus distilled water
68133 Plot photometric reading at 650 nm or at 815 nm versus ug of silica in
56 5 ml.
68134 For turbidity correction use 6 1, 6 2 if used and 6 8 2-6 811 omitting
684and689
6 8 13 5 Run a reagent blank and at least one standard (to check calibration
curve drift) with each group of samples
6 8 14 Visual comparison
6 8 14 1 Prepare not less than 12 standards covering the range of 0 to 120 ug
SiO2 by placing the calculated volumes of standard silica (5 8) in 50 ml
Nessler tubes, diluting to the mark and develop the color as in
682-68 11
370 1-4
-------
7 Calculations
7 1 Read ug SiO2 from calibration curve or by visual comparison
7 2 mg/1 Si02 =
ug/SiO2
ml sample
7 3 Report whether NaHCO3 digestion (6 2) was used
8 Precision and Accuracy
81 A synthetic unknown sample containing 5 0 mg/1 SiO2, 10 mg/1 chloride, 0 200 mg/1
ammonia N, 1 0 mg/1 nitrate N, 1 5 mg/1 organic N, and 10 0 mg/1 phosphate in
distilled water was analyzed in 19 laboratories by the molybdosihcate method, with a
relative standard deviation of 143% and a relative error of 7 8%
8 2 Another synthetic unknown sample containing 15 0 mg/1 SiO2, 200 mg/1 chloride,
0 800 mg/1 ammonia N, 1 0 mg/1 nitrate N, 0 800 mg/1 organic N, and 5 0 mg/1
phosphate in distilled water was analyzed in 19 laboratories by the molybdosihcate
method, with a relative standard deviation of 8 4% and a relative error of 4 2%
83 A third synthetic unknown sample containing 30 0 mg/1 SiO2, 400 mg/1 chloride, 1 50
mg/1 ammonia N, 1 0 mg/1 nitrate N, 0 200 mg/1 organic N, and 0 500 mg/1
phosphate in distilled water was analyzed in 20 laboratories by the molybdosihcate
method, with a relative standard deviation of 77% and a relative error of 9 8% All
results were obtained after sample digestion with NaHCO3
8 4 Photometric evaluations by the ammo-naphthol-sulfonic acid procedure have an
estimated precision of ±010 mg/1 in the range from 0 to 2 mg/1 (ASTM)
8 5 Photometric evaluations of the sihco-molybdate color in the range from 2 to 50 mg/1
have an estimated precision of approximately 4% of the quantity of silica measured
(ASTM)
Bibliography
1 Annual Book of ASTM Standards, Part 31, "Water", Standard D859-68, p 401 (1976)
2 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 487,
Method 426B,( 1975)
370 1-5
-------
SULFATE
Method 375.1 (Colorimetric, Automated, Chloranilate)
STORET NO. Total 00945
1 Scope and Application
1 1 This automated method is applicable to drinking and surface waters, domestic and
industrial wastes, in the range of 10 to 400 mg SO4/1 Approximately 15 samples per
hour can be analyzed
2 Summary of Method
2 1 When solid barium chloramlate is added to a solution containing sulfate, barium sulfate
is precipitated, releasing the highly colored acid chloramlate ion The color intensity in
the resulting chloramhc acid is proportional to the amount of sulfate present
3 Sample Handling and Preservation
3 1 Refrigeration at 4°C
4 Interferences
4 1 Cations, such as calcium, aluminum, and iron, interfere by precipitating the chloramlate
These ions are removed automatically by passage through an ion exchange column
5 Apparatus
5 1 Techmcon AutoAnalyzer consisting of
5 1 1 Sampler I
512 Continuous filter
5 1 3 Manifold
514 Proportioning pump
515 Colorimeter equipped with 15 mm tubular flow cell and 520 nm filters
516 Recorder
5 17 Heating bath, 45°C
5 2 Magnetic stirrer
6 Reagents
6 1 Barium chloramlate Add 9 g of barium chloramlate (BaC6Cl2O4) to 333 ml of ethyl
alcohol and dilute to 1 liter with distilled water
6 2 Acetate buffer, pH 4 63 Dissolve 13 6 g of sodium acetate in distilled water Add 6 4 ml
of acetic acid and dilute to 1 liter with distilled water Make fresh weekly
6 3 NaOH-EDTA solution Dissolve 65 g of NaOH and 6 g of EDTA in distilled water and
dilute to 1 liter
NOTE 1: This solution is also used to clean out manifold system at end of sampling run
6 4 Ion exchange resin Dowex-50 W-X8, ionic form-H+
NOTE 2: Column is prepared by sucking a slurry of the resin into 12 inches of 3/16-inch
OD sleeving This may be conveniently done by using a pipette and a loose-fitting glass
wool plug in the sleeve The column, upon exhaustion, turns redv
Issued 1971
375 1-1
-------
6 5 Stock solution Dissolve 1 4790 g of oven-dried (105°C) Na2SO4 in distilled water and
dilute to 1 liter ma volumetric flask 1 0 ml =10mg
651 Prepare a series of standards by diluting suitable volumes of stock solution to 100 0
ml with distilled water The following dilutions are suggested
ml of Stock Solution Cone, mg/1
10 10
20 20
40 40
60 60
80 80
10 0 100
15 0 150
200 200
300 300
400 400
7. Procedure
7.1 Set up manifold as shown in Figure 1 (Note that any precipitated BaSO4 and the unused
barium chloramlate are removed by filtration If any BaSO4 should come through the
filter, it is complexed by the NaOH-EDTA reagent)
7 2 Allow both colorimeter and recorder to warm up for 30 minutes Run a baseline with all
reagents, feeding distilled water through the sample line Adjust dark current and
operative opening on colorimeter to obtain suitable baseline
7 3 Place distilled water wash tubes in alternate openings in sampler and set sample timing at
2 0 minutes
7 4 Place working standards in sampler in order of decreasing concentration Complete
filling of sampler tray with unknown samples
7 5 Switch sample line from distilled water to sampler and begin analysis
8. Calculation
8 1 Prepare standard curve by plotting peak heights of processed standards against known
concentrations Compute concentration of samples by comparing sample peak heights
with standard curve
9. Precision and Accuracy
9.1 In a single laboratory (EMSL), using surface water samples at concentrations of 39, 111,
188 and 294 mg SO4/1, the standard deviations were ±06, ±10, ±22 and ±08,
respectively
92 In a single laboratory (EMSL), using surface water samples at concentrations of 82 and
295 mg SO4/1, recoveries were 99% and 102%, respectively
Bibliography
1 Barney, J E, and Bertolocmi, R J , Anal Chem , 29,283 (1957)
2 Gales, M E, Jr, Kaylor, W H and Longbottom, J E, "Determination of Sulphate by
Automatic Colonmetnc Analysis", Analyst, 93,97 (1968)
375 1-2
-------
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-------
SULFATE
Method 375.2 (Colorimetric, Automated, Methylthymol Blue, AA II)
STORET NO. 00945
Scope and Application
1 1 This automated method is applicable to drinking and surface waters, domestic and
industrial wastes
1 2 Samples in the range of 3 to 300 mg SO4/1 can be analyzed The sensitivity of the method
can be increased by a minor modification to analyze samples in the range of 0 5 to 30 mg
SO4/1 Approximately 30 samples per hour can be analyzed
Summary of Method
2 1 The sample is first passed through a sodium form cation-exchange column to remove
multivalent metal ions The sample containing sulfate is then reacted with an alcohol
solution of barium chloride and methylthymol blue (MTB) at a pH of 2 5-3 0 to form
barium sulfate The combined solution is raised to a pH of 12 5-13 0 so that excess
barium reacts with MTB The uncomplexed MTB color is gray, if it is all chelated with
barium, the color is blue Initially, the barium and MTB are equimolar and equivalent to
300 mg SO4/1, thus the amount of uncomplexed MTB is equal to the sulfate present
Sample Handling and Preservation
3 1 Refrigeration at 4°C
Interferences
4 1 The ion exchange column eliminates interferences from multivalent cations A mid-scale
sulfate standard containing Ca++ should be analyzed periodically to insure that the
column is functioning properly
4 2 Samples with pH below 2 should be neutralized because high acid concentrations elute
cations from the ion exchange resin
4 3 Turbid samples should be filtered or centnfuged
Apparatus
5 1 Techmcon Auto Analyzer consisting of
511 Sampler
512 Manifold-high or low level (Figure I)
513 Proportioning pump
514 Colorimeter equipped with 15 mm flow cell and 460 nm interference filters
515 Recorder
516 Digital Printer for AAII (optional)
Reagents
6 1 Barium chloride Dissolve 1 526 g of barium chloride dihydrate (BaCl2«2H2O) in 500 ml
of distilled water and dilute to 1 liter
Pending approval for NPDES
Issued 1978
375 2-1
-------
62 Methylthymol blue Dissolve 01182 g of methylthymol blue (3'3"-bis-N,N-bis
carboxymethyl)-amino methylthymolsulfone-phthalem pentasodmm salt) in 25 ml of
barium chloride solution (6 1) Add 4 ml of 1 0 N hydrochloric acid which changes the
color to bright orange Add 71 ml of water and dilute to 500 ml with ethanol The pH of
this solution is 2 6 This reagent should be prepared the day before and stored in a brown
plastic bottle in the refrigerator
6 3 Buffer, pH 10 5 ±05 Dissolve 6 75 g of ammonium chloride in 500 ml of distilled
water Add 57 ml of concentrated ammonium hydroxide and dilute to one liter with
distilled water
6 4 Buffered EDTA Dissolve 40 g of tetrasodium EDTA in pH 10 5 buffer (6 3), and dilute
to one liter with buffer
6 5 Sodium hydroxide solution, (50%) Dissolve 500 g NaOH in 600 ml of distilled water,
cool, and dilute to 1 liter
6 6 Sodium hydroxide, 0 18N Dilute 14 4 ml of sodium hydroxide solution (6 5) to 1 liter
6 7 Ion exchange resin Bio-Rex 70, 20-50 mesh, sodium form, Bio-Rad Laboratories,
Richmond, California Free from fines by stirring with several portions of deiomzed
water and decant the supernate before settling is complete
6 8 Dilution Water Add 0 75 ml of sulfate stock solution (6 9) and 3 drops of Bnj-35 to 2
liters of distilled water
6 9 Sulfate stock solution, 1 ml = 1 mg SO4 Dissolve 1 479 g of dried (105°C) Na2SO4 in
distilled water and dilute to 1 liter
6 10 Dilute sulfate solution, 1 ml = 0 1 mg SO4 Dilute 100 ml of sulfate stock solution (6 9)
to 1 liter
6 11 High level working standards, 10-300 mg/1 Prepare high level working standards by
diluting the following volumes of stock standard (6 9) to 100 ml
ml stock mg/1 SO4
1 10
5 50
10 100
15 150
25 250
30 300
6 12 Low level working standards, 1-30 mg/1 Prepare low level working standards by
diluting the following volumes of dilute sulfate solution (6 10) to 100 ml
ml stock mg/1 SO4
1 10
5 50
10 100
15 150
25 250
30 300
375 2-2
-------
7 Procedure
7 1 Set up the manifold for high (0-300 mg SO4/1) or low (0-30 mg SO4/1) level samples as
described in Figure I
7 2 The ion exchange column is prepared by pulling a slurry of the resin into a piece of glass
tubing 7 5 inches long, 2 0 mm ID and 3 6 mm OD This is conveniently done by using a
pipet and a loose fitting glass wool plug in the tubing Care should be taken to avoid
allowing air bubbles to enter the column If air bubbles become trapped, the column
should be prepared over again The column can exchange the equivalent of 35 mg of
calcium For the high level manifold this corresponds to about 900 samples with 200
mg/1 Ca The column should be prepared as often as necessary to assure that no more
than 50% of its capacity is used up
7 3 Allow the colorimeter, recorder and printer to warm up for 30 minutes Pump all
reagents until a stable baseline is achieved
7 4 Analyze all working standards in duplicate at the beginning of a run to develop a
standard curve The A and B control standards are analyzed every hour to assure that the
system remains properly calibrated Since the chemistry is non-linear the 180 mg/1
standard is set at 50% on the recorder using the standard calibration control on the
colorimeter
75 At the end of each day, the system should be washed with the buffered EDTA solution
(6 4) This is done by placing the methylthymol blue line and the sodium hydroxide line
in water for a few minutes and then in the buffered EDTA solution for 10 minutes Wash
the system with water for 15 minutes before shutting down
8 Calculation
8 1 Prepare a standard curve by plotting peak heights of processed standards against known
concentrations Compute concentration of samples by comparing sample peak heights
with the standard curve
9 Precision and Accuracy
91 In a single laboratory the estimated standard deviation, calculated from duplicate
analyses of 26 surface and wastewaters at a mean concentration of 110 mg/1 was +16
mg/1
9 2 The mean recovery from 24 surface and wastewaters was 102%
Bibliography
1 Lazrus, A L , Hill, K C and Lodge, J P , "Automation in Analytical Chemistry", Techmcon
Symposia, 1965
2 Coloros, E, Panesar, M R and Parry, F P, "Linearizing the Calibration Curve m
Determination of Sulfate by the Methylthymol Blue Method", Anal Chem 48, 1693(1976)
375 2-3
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SULFATE
Method 375.3 (Gravimetric)
STORET NO. Total 00945
1 Scope and Application
1 1 This method is applicable to drinking, surface and saline water, domestic and industrial
wastes
1 2 This method is the most accurate method for sulfate concentrations above 10 mg/1
Therefore, it should be used whenever results of the greatest accuracy are required
2 Summary of Method
2 1 Sulfate is precipitated as barium sulfate in a hydrochloric acid medium by the addition of
barium chloride After a period of digestion, the precipitate is filtered, washed with hot
water until free of chloride, ignited, and weighed as BaSO4
2 2 Preserve by refrigeration at 4°C
3 Interferences
3 1 High results may be obtained for samples that contain suspended matter, nitrate, sulfite
and silica
3 2 Alkali metal sulfates frequently yield low results This is especially true of alkali
hydrogen sulfates Occlusion of alkali sulfate with barium sulfate causes the substitution
of an element of lower atomic weight than barium in the precipitate Hydrogen sulfate of
alkali metal acts similarly and decomposes when heated Heavy metals such as
chromium and iron, cause low results by interfering with complete precipitation and by
formation of heavy metal sulfates
4 Apparatus
4 1 Steam bath
4 2 Drying oven, equipped with thermostatic control
4 3 Muffle furnace with heat indicator
4 4 Desiccator
4 5 Analytical balance, capable of weighing to 0 1 mg
4 6 Filter paper, acid-washed, ashless hard-finish filter paper sufficiently retentive for fine
precipitates
5 Reagents
5 1 Methyl red indicator solution Dissolve 100 mg methyl red sodium salt in distilled water
in a 100 ml volumetric flask and dilute to the mark with distilled water
5 2 Hydrochloric acid, HC1, 1 +1
5 3 Barium chloride solution Dissolve 100 g BaCl2«2H2O in 1 liter of distilled water Filter
through a membrane filter or hard-finish filter paper One ml of this reagent is capable of
precipitating approximately 40 mg SO4
Approved for NPDES
Issued 1974
Editorial revision 1978
375 3-1
-------
5 4 Silver nitrate-nitric acid reagent Dissolve 8 5 g AgNO3 and 0 5 ml cone HNO3 m 500 ml
distilled water
6. Procedure
6 1 Removal of silica If silica concentration is greater than 25 mg/1
611 Evaporate sample nearly to dryness in a platinum dish on a steam bath
6 1 2 Add 1 ml HC1 solution (5 2), tilt dish and rotate until acid contacts all of the
residue
613 Continue evaporation to dryness
614 Complete drying in an oven at 180°C
615 If organic matter present, char over a flame
616 Moisten with 2 ml distilled water and 1 ml HC1 solution (5 2)
617 Evaporate to dryness on a steam bath
6 1 8 Add 2 ml HC1 solution (5 2)
6.1 9 Take up soluble residue in hot distilled water and filter
6 1 10 Wash the insoluble silica with several small portions of hot distilled water
6.1 11 Combine filtrate and washings
6 2 Precipitation of barium sulfate
621 If necessary, treat clarified sample to remove interfering agents
622 Adjust to contain approximately 50 mg SO4 ion m a 250 ml volume
623 Adjust acidity with HC1 solution (5 2) to pH 4 5 to 5 0, using pH meter or orange
color of methyl red indicator (5 1)
624 Add an additional 1 to 2 ml HC1 solution (5 2)
6.2 5 For lower concentrations of sulfate ion fix the total volume at 150 ml
6 2.6 Heat to boiling and, while stirring gently, add warm BaCl2 solution (5 3) slowly,
until precipitation appears to be complete, then add approximately 2 ml in excess
627 If amount of precipitate is small, add a total of 5 ml BaCl2 solution (5 3)
628 Digest the precipitate at 80 to 90°C preferably overnight but for not less than 2
hours
6 3 Filtration and Weighing
631 Mix a little ashless filter paper pulp with the BaSO4 and filter at room temperature
632 Wash the precipitate with small portions of warm distilled water until the washings
are free of chloride as indicated by testing with silver nitrate-nitric acid reagent
(54)
633 Dry the filter and precipitate
634 Ignite at 800°C for 1 hour DO NOT LET THE FILTER PAPER FLAME
635 Cool m a desiccator and weigh
7 Calculation
mg/1 SO4 = mgBaSCX, x 411 5
ml sample
375 3-2
-------
8 Precision and Accuracy
81 A synthetic unknown sample containing 259 mg/1 sulfate, 108 mg/1 Ca, 82 mg/1 Mg,
3 1 mg/1 K, 19 9 mg/1 Na, 241 mg/1 chloride, 250 ug/1 nitrite N, 1 1 mg/1 nitrate N
and 42 5 mg/1 alkalinity (contributed by NaHCO3), was analyzed in 32 laboratories by
the gravimetric method, with a relative standard deviation of 4 7% and a relative error of
19%
Bibliography
1 Annual Book of ASTM Standards, Part 31, "Water", Standard D516-68, Method A, p 429
(1976)
2 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 493,
Method 427A, (1975)
375 3-3
-------
SULFATE
Method 375.4 (Turbidimetric)
STORET NO. Total 00945
Scope and Application
1 1 This method is applicable to drinking and surface waters, domestic and industrial wastes
1 2 The method is suitable for all concentration ranges of sulfate, however, m order to obtain
reliable readings, use a sample aliquot containing not more than 40 mg SO4/1
1 3 The minimum detectable limit is approximately 1 mg/1 sulfate
Summary of Method
2 1 Sulfate ion is converted to a barium sulfate suspension under controlled conditions The
resulting turbidity is determined by a nephelometer, filter photometer or
spectrophotometer and compared to a curve prepared from standard sulfate solutions
2 2 Suspended matter and color interfere Correct by running blanks from which the barium
chloride has been omitted
2 3 Silica in concentrations over 500 mg/1 will interfere
Comments
3 1 Proprietary reagents, such as Hach Sulfaver or equivalent, are acceptable
32 Preserve by refrigeration at 4°C
Apparatus
4 1 Magnetic starrer, variable speed so that it can be held constant just below splashing Use
identical shape and size magnetic stirring bars
4 2 Photometer one of the following which are given in order of preference
421 Nephelometer
422 Spectrophotometer for use at 420 nm with light path of 4 to 5 cm
423 Filter photometer with a violet filter having a maximum near 420 nm and a light
path of 4 to 5 cm.
4 3 Stopwatch, if the magnetic stirrer is not equipped with an accurate timer
4 4 Measuring spoon, capacity 0 2 to 0 3 ml
Reagents
5 1 Conditioning reagent Place 30 ml cone HC1, 300 ml distilled water, 100 ml 95% ethanol
or isopropanol and 75 g NaCl m solution m a container Add 50 ml glycerol and mix
5 2 Barium chloride, BaCl2, crystals, 20 to 30 mesh
5 3 Sodium carbonate solution (approximately 0 05N) Dry 3 to 5 g primary standard
Na2CO3 at 250°C for 4 hours and cool in a desiccator Weigh 25 ±0 2 g (to the nearest
mg), transfer to a 1 liter volumetric flask and fill to the mark with distilled water
Approved for NPDES
Issued 1971
Editorial revision 1978
375 4-1
-------
5 4 Standard sulfate solution (1 00 ml =*= 100 ug SO4) Prepare by either 5 4 1 or 5 4 2
5 4 1" Standard sulfate solution from H2SO4
5411 Standard sulfunc acid, 0 IN dilute 3 0 ml cone H2SO4 to 1 liter with
distilled water Standardize versus 40 00 ml of 0 05 NjNa2CO3 solution
( (53) with about 60 ml distilled water by titrating potentiometrically to
' pH about 5 Lift electrodes and rinse into beaker Boil gently for 3-5
minutes under a watch glass cover Cool to room temperature Rinse
cover glass into beaker Continue titration to the pH inflection point
Calculate normality using
N= Ax B
53 OQ x C
where
A = g Na2CO3 weighed into 1 liter
' B = ml Nfa2CO3 solution
C = ml acid used to inflection point
5412 Standard acid, 0 02 N^ Dilute appropriate amount of standard acid, 0 1
N.(5 4 1 1) to 1 liter (200 00 ml if 0 1000 N) Check by standardization
versus 15 ml of 0 05 N_Na2CO3 solution (5 3)
5413 Place 10 41 ml standard sulfunc acid, 0 02 ]S[ (5 4 1 2) in a 100 ml
volumetric and dilute to the mark
542 Standard sulfate solution from Na2SO4 Dissolve 147 9 mg anhydrous Na2SO4 in
distilled water in a 1 liter volumetric flask and dilute to the mark with distilled
water
Procedure
6 1 Formation of barium sulfate turbidity
6 1 1 Place 100 ml sample, or a suitable portion diluted to 100 ml) into a 250 Erlenmeyer
flask
612 Add exactly 5 0 ml conditioning reagent (5 1).
6 1 3 Mix in the stirring apparatus
6 1 4 While the solution is being stirred, add a measuring spoonful of BaCl2 crystals (5 2)
and begin timing immediately
6 1 5 Stir exactly 1 0 minutes at constant speed
6 2 Measurement of barium sulfate turbidity
6 2 1 Immediately after the stirring period has ended, pour solution into absorbance cell
6 2,2 Measure turbidity at 30 second intervals for 4 minutes
623 Record the maximum reading obtained in the 4 minute period
6 3 Preparation of calibration curve
6 3 1 Prepare calibration curve using standard sulfate solution (5 4)
632 Space standards at 5 mg/1 increments in the 0-40 mg/1 sulfate range
375 4-2
i
-------
633 Above 50 mg/1 the accuracy decreases and the suspensions lose stabilityi
634 Check reliability of calibration curve by running a standard with every 3 or 4
samples
6 4 Correction for sample color and turbidity
6 4 1 Run a sample blank using the proceduie 6 1 and 6.2 without the addition of barium
chloride (6 14)
Calculations
7 1 Read mg SO4 from calibration curve
mg SO4/1 = mgSO4 x 1,000
ml sample
Precision and Accuracy
8 1 Thirty-four analysts in 16 laboratories analyzed six synthetic water samples containing
exact increments of inorganic sulfate with the following results-
Increment as
Sulfate
mg/liter
86
92
110
122
188
199
Precision as
Standard Deviation
mg/liter
230
178
786
750
958
118
Accuracy as
Bias,
-372
-8.26
-301
-337
+004
-170
Bias
mg/liter
-03
-08
-33
-41
+01
-34
(FWPCA Method Study 1, Mineral and Physical Analyses)
82 A synthetic unknown sample containing 259 mg/1 sulfate, 108 mg/1 Ca, 82 mg/1 Mg,
3 1 mg/1 K, 19 9 mg/1 Na, 241 mg/1 chloride, 0 250 mg/1 nitrite N, 1 1 mg/1 nitrate
N, and 42 5 mg/1 total alkalinity (contributed by NaHCO3) was analyzed in 19
laboratories by the turbidimetnc method, with a relative standard deviation of 9 1% and
a relative error of 1 2%
Bibliography
1 Annual Book of ASTM Standards, Part 31, "Water", Standard D5 16-68, Method B, p 430
(1976)
2 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 496,
Method 427C, (1975)
375.4-3
-------
SULFIDE
Method 376.1 (Titrimetric, Iodine)
STORET NO. Total 00745
Dissolved 00746
1 Scope and Application
1 1 This method is applicable to the measurement of total and dissolved sulfides in drinking,
surface and saline waters, domestic and industrial wastes
1 2 Acid insoluble sulfides are not measured by the use of this test (Copper sulfide is the only
common sulfide in this class)
1 3 This method is suitable for the measurement of sulfide in concentrations above 1 mg/1
2 Summary of Method
2 1 Excess iodine is added to a sample which may or may not have been treated with zinc
acetate to produce zinc sulfide The iodine oxidizes the sulfide to sulfur under acidic
conditions The excess iodine is backtitrated with sodium thiosulfate or phenylarsine
oxide
3 Comments
3 1 Reduced sulfur compounds, such as sulfite, thiosulfate and hydrosulfite, which
decompose in acid may yield erratic results Also, volatile iodine-consuming substances
will give high results
3 2 Samples must be taken with a minimum of aeration Sulfide may be volatilized by
aeration and any oxygen inadvertently added to the sample may convert the sulfide to an
unmeasurable form
33 If the sample is not preserved with zinc acetate and NaOH, the analysis must be started
immediately Similarly, the measurement of dissolved sulfides mut also be commenced
immediately
4 Apparatus Ordinary laboratory glassware
5 Reagents
5 1 Hydrochloric acid, HC1,6 N
5 2 Standard iodine solution, 0 0250 N Dissolve 20 to 25 g KI in a little water in a liter
volumetric and add 3 2 g iodine Allow to dissolve Dilute to 1 liter and standardize
against 0 0250 N sodium thiosulfate or phenylarsine oxide using a starch indicator
5 3 Phenylarsine oxide 0 0250 N commercially available
5 4 Starch indicator commercially available
5 5 Procedure for standardization (see Residual Chlonne-iodometnc titration Method
330 3, section 5 15)
Approved for NPDES
Issued 1971
Editorial revision 1978
376 1-1
-------
Procedure
6 1 Unprecipitated sample
6 1 1 Place a known amount of standard iodine solution (5 2) into a 500 ml flask The
amount should be estimated to be in excess of the amount of sulfide expected
612 Add distilled water, if necessary, to bring the volume to approximately 20 ml
6 1 3 Add2mlof6NHCl(5 1)
6 1 4 Pipet 200 ml of sample into the flask, keeping the tip of the pipet below the surface
of the sample
615 If the iodine color disappears, add more iodine until the color remains Record the
total number of millihters of standard iodine used in performing steps 611 and
615
6 1 6 Titrate with the reducing solution (0 0250 N sodium thiosulfate or 0 0250 N
phenylarsme oxide solution (5 3)) using a starch indicator (5 4) until the blue color
disappears Record the number of millihters used
6 2 Precipitated samples
621 Add the reagents to the sample in the original bottle Perform steps 611,613,
6 1 5, and 6 1 6
6 3 Dewatered samples
6 3 1 Return the glass fibre filter paper which contains the sample to the original bottle
Add 200 ml distilled water Perform steps 6 1 1,6 1 3, 6 1 5, and 6 1 6
632 The calculations (7) should be based on the volume of original sample put through
the filter
Calculations
7.1 One ml of 0 0250 N standard iodine solution (5 2) reacts with 0 4 mg of sulfide present in
the titration vessel
7 2 Use the formula
mg/1 sulfide = 400 (A - B)
ml sample
where
A = ml of 0 0250 Nstandard iodine solution (5 2)
B = ml of 0 0250N standard reducing sodium thosulfate or phenylarsme oxide)
solution (5 3)
8. Precision and Accuracy
8 1 Precision and accuracy for this method have not been determined
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 505,
Method 428D, (1975)
376 1-2
-------
SULFIDE
Method 376.2 (Colorimetric, Methylene Blue)
STORET NO. Total 00745
Dissolved 00746
Scope and Application
1 1 This method is applicable to the measurement of total and dissolved sulfides in drinking,
surface and saline waters, domestic and industrial wastes
1 2 Acid insoluble sulfides are not measured by this method Copper sulfide is the only
common sulfide in this class
1 3 The method is suitable for the measurement of sulfide in concentrations up to 20 mg/1
Summary of Method
2 1 Sulfide reacts with dimethyl-p-phenylenediamme (p-ammodimethyl aniline) in the
presence of ferric chloride to produce methylene blue, a dye which is measured at a
wavelength maximum of 625 nm,
Comments
3 1 Samples must be taken with a minimum of aeration Sulfide may be volatilized by
aeration and any oxygen inadvertently added to the sample may convert the sulfide to an
unmeasurable form Dissolved oxygen should not be present in any water used to dilute
standards
3 2 The analysis must be started immediately
3 3 Color and turbidity may interfere with observations of color or with photometric
readings
Apparatus
4 1 Matched test tubes, approximately 125 mm long and 15 mm O D
4 2 Droppers, delivering 20 drops/ml To obtain uniform drops, hold dropper in vertical
position and allow drops to form slowly
4 3 Photometer, use either 43 1 or 4 3 2
431 Spectrophotometer, for use at 625 nm with cells of 1 cm and 10 cm light path
432 Filter photometer, with filter providing transmittance near 625 nm
Reagents
5 1 Ammo-sulfunc acid stock solution Dissolve 27 g N,N-dimethyl-p-phenylenediamme
oxalate (p-aminodimethylanihne) in a cold mixture of 50 ml cone H2SO4 and 20 ml
distilled water in a 100 ml volumetric flask Cool and dilute to the mark If dark discard
and purchase fresh reagent Store in dark glass bottle
5 2 Ammo-sulfunc acid reagent Dissolve 25 ml amino-sulfunc acid stock solution (5 1) with
975 ml of 1 +1 H2SO4 (5 4) Store in a dark glass bottle This solution should be clear
5 3 Ferric chloride solution Dissolve 100 g FeCl3»6H2O in 40 ml distilled water
Approved for NPDES
Issued 1978
376 2-1
-------
5 4 Sulfunc acid solution, H2SO4,1 +1
5.5 Diammomum hydrogen phosphate solution Dissolve 400 g (NH4)2HPO4 m 800 ml
distilled water
5 6 Methylene blue solution I Dissolve 1 0 g of methylene blue in distilled water m a 1 liter
volumetric flask and dilute to the mark Use U S P grade or one certified by the
Biological Stain Commission The dye content reported on the label should be 84% or
more Standardize (5 8) against sulfide solutions of known strength and adjust
concentration so that 0 05 ml (1 drop) equals 1 0 mg/1 sulfide
5 7 Methylene blue solution II Dilute 10 00 ml of adjusted methylene blue solution I (5 6) to
100 ml with distilled water in a volumetric flask
5 8 Standardization of methylene blue I solution
581 Place several grams of clean, washed crystals of sodium sulfide Na2S«9H2O m a
small beaker
582 Add somewhat less than enough water to cover the crystals
583 Stir occasionally for a few minutes Pour the solution into another vessel This
reacts slowly with oxygen but the change is insigmficnat over a few hours Make
the solution daily
5.8 4 To 1 liter of distilled water add 1 drop of solution and mix
5.8 5 Immediately determine the sulfide concentration by the methylene blue procedure
(6) and by the titrimetnc iodide procedure (Method 376 1, this manual)
586 Repeat using more than one drop of sulfide solution or less water until at least five
tests have been made in the range of 1 to 8 mg/1 sulfide
587 Calculate the average percent error of the methylene blue procedure (6) as
compared to the titnmetnc iodide procedure (Method 376 1)
588 Adjust by dilution or by adding more dye to methylene blue solution I (5 6)
Procedure
6 1 Color development
6.1 1 Transfer 7 5 ml of sample to each of two matched test tubes using a special wide
tipped pipet or filling to a mark on the test tubes
6 1 2 To tube A add 0 5 ml amine-sulfunc acid reagent (5 2) and 0 15 ml (3 drops) FeCl3
solution (5 3)
613 Mix immediately by inverting the tube only once
6 1 4 To tube B add 0 5 ml 1 +1 H2SO4 (5 4) and 0 15 ml (3 drops) FeCl3 solution (5 3)
and mix
6.1 5 Color will develop in tube A in the presence of sulfide Color development is
usually complete in about 1 minute, but a longer time is often required for the
fading of the initial pink color
6.1 6 Wait 3 to 5 minutes
6 1 7 Add 1 6 ml (NH4)2HPO4 solution (5 5) to each tube
6 1.8 Wait 3 to 5 minutes and make color comparisons If zinc acetate was used wait at
least 10 minutes before making comparison
376 2-2
-------
6 2 Color comparison
6 2 1 Visual
6211 Add methylene blue solution I (5 6) and/or II (5 7) (depending on
sulfide concentration and accuracy desired) dropwise to tube B (6 1 4)
until the color matches that developed m the first tube
6212 If the concentration exceeds 20 mg/1, repeat 6211 using a portion of
the sample diluted to one tenth
622 Photometric
6221 Use a 1 cm cell for 0 1 to 2 0 mg/1 Use a 10 cm cell for up to 20 mg/1
6222 Zero instrument with portion of sample from tube B (6 1 4)
6223 Prepare calibration curve from data obtained in methylene blue
standardization (5 8), plotting concentraton obtained from titnmetric
iodide procedure (Method 376 1) versus absorbance A straight line
relationship can be assumed from 0 to 1.0 mg/1
6224 Read the sulfide concentration from the calibration curve
7 Calculations
7 1 Visual comparison With methylene blue solution I (5 6), adjusted so that 0 05 ml (1
drop) =10 mg/1 sulfide and a 7 5 ml sample
mg/1 sulfide = number drops methylene blue solution I (5 6) + 0 1 x [number of drops
methylene blue solution II (5 7)]
7 2 Photometric see 6 2 2 4
8 Precision and Accuracy
8 1 The precision has not been determined The accuracy is about ±10%
Bibliography
1 Standard Methods for he Examination of Water and Wastewater, 14th edition, p 503, Method
428C(1975)
376 2-3
-------
SULFITE
Method 377.1 (Titrimetric)
STORET NO. 00740
Scope and Application
1 1 This method is applicable to drinking and surface waters, sewage and industrial wastes
The pnmary application has been to cooling, process and distribution water systems and
boiler feedwaters to which sulfide is added in order to reduce dissolved oxygen and
eliminate corrosion
1 2 The minimum detectable limit is 2-3 mg/1 SO3
Summary of Method
2 1 An acidified sample containing a starch indicator is titrated with a standard potassium
lodide-iodate titrant to a faint permanent blue end point which appears when the
reducing power of the sample has been completely exhausted
Interferences
3 1 The temperature of the sample must be below 50°C
3 2 Care must be taken to allow as little contact with air as possible For example, do not
filter the sample Keep the bure{ tip below the surface of the sample
3 3 Other oxidizable substances, such as organic compounds, ferrous iron and sulfide are
positive interferences. Sulfide may be removed by adding 0 5g of zinc acetate and
analyzing the supernatant of the settled sample
3 4 Nitrite gives a negative interference by oxidizing sulfite when the sample is acidified, this
is corrected by either using a proprietary indicator which eliminates nitrite or by adding
sulfamic acid
3 5 Copper and possibly other heavy metals catalyze the oxidation of sulfite, EDTA is used
to complex metals
36 A blank must be run to correct for interferences present in the reagents
Apparatus
4 1 Standard laboratory glassware is used
Reagents
5 1 Sulfunc acid, H2SO4, 1 +1
5 2 Starch indicator Amylose, Mallmckrodt Chemical Works, Thyodene, Magnus
Chemical Co or equivalent
5 3 Dual-Purpose Sulfite Indicator Powder a proprietary formulation containing sulfamic
acid to destroy nitrite
54 Standard potassium lodide-iodate titrant, Q0125N_ Dissolve 4458 mg anhydrous
potassium lodate, KIO3 (pnmary standard grade dried for several hours at 120°C), 4 25g
Approved for NPDES
Issued 1974
Editorial revision 1978
377 1-1
-------
KI and 310 mg NaHCO3 in distilled water and dilute to 1 liter This titrant is equivalent
to500ugSO3/100ml
5 5 Sulfamic Acid Crystalline
5 6 EDTA Reagent Dissolve 2 5g EDTA in 100 ml distilled water
Procedure
6 1 Sampling
Contact with air must be minimized If the sample temperature is greater than 50°C, it
must be cooled m a special apparatus described elswhere (see Bibliography)
Immediately add 1 ml of EDTA Solution (5 6) per 100 ml of sample
6 2 Starch Indicator
6 2 1 Place 1 ml H2SO4 (5 1) in titration vessel
622 Add 0 1 g sulfamic acid crystals (5 5)
623 Add 50 ml sample
624 Add approximately 0 1 g starch indicator (5 2)
625 Titrate with potassium lodide-iodate titrant (5 4) until a faint permanent blue color
develops Keep the pipet tip below the surface of the sample View the color change
against a white background Record the ml titrant
626 Run a reagent blank using distilled water instead of sample (6 2 3)
6 3 Dual Purpose Sulfite Indicator Powder
631 Place 50 ml sample in a titration vessel
632 Add 3-4 drops phenolphthalem indicator
633 Add sufficient scoops (Ig) of indicator (5 3) to discharge the red color
634 Titrate with potassium lodide-iodate titrant (5 4) until a faint permanent blue color
develops View the color change against a white background Record the ml
titrant
635 Run a reagent blank using distilled water instead of sample (6 3 1)
Calculations
7 1 Use the formula
mg/lS03=AxfJx4i)'000
ml sample
where
A = ml titrant (6 2 5 or 6 3 4) B = ml
B = ml titrant for the blank (6 2 6 or 6 3 5) and
N = normality of KI-KIO3 titrant (5 4)
72 To calculate as Na2SO3
mg/1 Na2SO3 = mg/1 SO3 x 1 57
Precision and Accuracy
8 1 Precision and accuracy data are not available at this time
377 1-2
-------
Bibliography
1 Annual Book of ASTM Standards, Part 31, "Water", Standard D1339-72, Method C, p 440
(1976)
2 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 508,
Method 429, (1975)
377 1-3
-------
BIOCHEMICAL OXYGEN DEMAND
Method 405.1 (5 Days, 20°C)
STORET NO. 00310
Carbonaceous 80082
Scope and Application
1 1 The biochemical oxygen demand (BOD) test is used for determining the relative oxygen
requirements of municipal and industrial wastewaters Application of the test to organic
waste discharges allows calculation of the effect of the discharges on the oxygen
resources of the receiving water Data from BOD tests are used for the development of
engineering criteria for the design of wastewater treatment plants
1 2 The BOD test is an empirical bioassay-type procedure which measures the dissolved
oxygen consumed by microbial life while assimilating and oxidizing the organic matter
present The standard test conditions include dark incubation at 20°C for a specified time
period (often 5 days) The actual environmental conditions of temperature, biological
population, water movement, sunlight, and oxygen concentration cannot be accurately
reproduced in the laboratory Results obtained must take into account the above factors
when relating BOD results to stream oxygen demands
Summary of Method
2 1 The sample of waste, or an appropriate dilution, is incubated for 5 days at 20°C in the
dark The reduction in dissolved oxygen concentration during the incubation period
yields a measure of the biochemical oxygen demand
Comments
3 1 Determination of dissolved oxygen in the BOD test may be made by use of either the
Modified Wmkler with Full-Bottle Technique or the Probe Method in this manual
3 2 Additional information relating to oxygen demanding characteristics of wastewaters can
be gained by applying the Total Organic Carbon and Chemical Oxygen Demand tests
(also found in this manual)
3 3 The use of 60 ml incubation bottles m place of the usual 300 ml incubation bottles, in
conjunction with the probe, is often convenient
Precision and Accuracy
4 1 Eighty-six analysts in fifty-eight laboratories analyzed natural water samples plus an
exact increment of biodegradable organic compounds At a mean value of 2 1 and 175
mg/1 BOD, the standard deviation was ±0 7 and ±26 mg/1, respectively (EPA Method
Research Study 3)
4 2 There is no acceptable procedure for determining the accuracy of the BOD test
Approved for NPDES CBOD pending approval for Section 304(h), CWA
Issued 1971
Editorial revision 1974
405 1-1
-------
5 References
5 1 The procedure to be used for this determination is found in
Standard Methods for the Examination of Water and Wastewater, 15th
Edition, p 483, Method 507 (1980)
5 2 Young, J C, "Chemical Methods for Nitrification Control," J Water
Poll Control Fed, 45, p 637 (1973)
405 1-2
-------
CHEMICAL OXYGEN DEMAND
Method 410.1 (Titrimetric, Mid-Level)
STORET NO. 00340
i Scope and Application
1 1 The Chemical Oxygen Demand (COD) method determines the quantity of oxygen
required to oxidize the organic matter in a waste sample, under specific conditions of
oxidizing agent, temperature, and time
1 2 Since the test utilizes a specific chemical oxidation the result has no definite relationship
to the Biochemical Oxygen Demand (BOD) of the waste or to the Total Organic Carbon
(TOC) level The test result should be considered as an independent measurement of
organic matter in the sample, rather than as a substitute for the BOD or TOC test
1 3 The method can be applied to domestic and industrial waste samples having an organic
carbon concentration greater than 50 mg/1 For lower concentrations of carbon such as
in surface water samples, the Low Level Modification should be used When the chloride
concentration of the sample exceeds 2000 mg/1, the modification for saline waters is
required
2 Summary of Method
2 1 Organic and oxidizable inorganic substances nxthe sample are oxidized by potassium
dichromate in 50% sulfunc acid solution at reflux temperature Silver sulfate is used as a
catalyst and mercuric sulfate is added to remove chloride interference The excess
dichromate is titrated with standard ferrous ammonium sulfate, using
orthophenanthrolme ferrous complex as an indicator
3 Sampling and Preservation
3 1 Collect the samples in glass bottles, if possible Use of plastic containers is permissible if it
is known that no organic contaminants are present in the containers
3 2 Biologically active samples should be tested as soon as possible Samples containing
settleable material should be well mixed, preferably homogenized, to permit removal of
representative aliquots
3 3 Samples should be preserved with sulfunc acid to a pH < 2 and maintained at 4°C until
analysis
4 Interferences
4 1 Traces of organic material either from the glassware or atmosphere may cause a gross,
positive error
411 Extreme care should be exercised to avoid inclusion of organic materials in the
distilled water used for reagent preparation or sample dilution
412 Glassware used in the test should be conditioned by running blank procedures to
eliminate traces of organic material
Approved for NPDES
Issued 1971
Editorial revision 1978
410 1-1
-------
4 2 Volatile materials may be lost when the sample temperature rises during the sulfunc acid
addition step To minimize this loss the flask should be cooled during addition of the
sulfunc acid solution
4 3 Chlorides are quantitatively oxidized by dichromate and represent a positive
interference Mercuric sulfate is added to the digestion flask to complex the chlorides,
thereby effectively eliminating the interference on all but brine and estuarme samples
5. Apparatus
5 1 Reflux apparatus Glassware should consist of a 500 ml Erlenmeyer flask or a 300 ml
round bottom flask made of heat-resistant glass connected to a 12 inch Alhhn condenser
by means of a ground glass joint Any equivalent reflex apparatus may be substituted
provided that a ground-glass connection is used between the flask and the condenser
6 Reagents
6.1 Distilled water Special precautions should be taken to insure that distilled water used in
this test be low in organic matter
6 2 Standard potassium dichromate solution (0 250 N) Dissolve 12 259 g K2Cr2O7, primary
standard grade, previously dried at 103°C for two hours, in distilled water and dilute to
1000ml
6 3 Sulfunc acid reagent Cone H2SO4 containing 23 5g silver sulfate, Ag2SO4, per 4 09kg
bottle With continuous stirnng, the silver sulfate may be dissolved m about 30 minutes
6.4 Standard ferrous ammonium sulfate (0 25 N) Dissolve 98 0 g of Fe(NH4)2(SO4)2»6H2O
in distilled water Add 20 ml of cone H2SO4 (6 8), cool and dilute to 1 liter This solution
must be standardized daily against standard K2Cr2O7 solution (6 2)
641 Standardization To approximately 200 ml of distilled water add 25 0 ml of 0 25 N
K2Cr2O7 (6 2) solution Add 20 ml of H2SO4 (6 8) and cool Titrate with ferrous
ammonium sulfate (6 4) using 3 drops of ferroin indicator (66) The color change
is sharp, going from blue-green to reddish-brown
Normality = (ml K2Cr2O,)(0 25)
ml Fe (NH<)2 (SO,)2
6.5 Mercunc sulfate Powdered HgSO4
6.6 Phenanthrolme ferrous sulfate (ferroin) indicator solution Dissolve 1 48 g of 1-10
(ortho) phenanthrohne monohydrate, together with 0 70 g of FeSO4»7H2O in 100 ml of
water This indicator may be purchased already prepared
67 Sliver sulfate Powdered Ag2SO4
6.8 Sulfunc acid (sp gr 1 84) Concentrated H2SO4
Procedure
7 1 Place several boiling stones in the reflux flask, followed by 50 0 ml of sample or an
aliquot diluted to 50 0 ml and 1 g of HgSO4 (6 5) Add 5 0 ml cone H2SO4 (6 8), swirl
until the mercunc sulfate has dissolved Place reflux flask in an ice bath and slowly add,
With swirling, 25 0 ml of 0 25 N K2Cr2O7 (6 2) Now add 70 ml of sulfunc acid-silver
410 1-2
-------
sulfate solution (6 3) to the cooled reflux flask, again using slow addition with swirling
motion
Caution Care must be taken to assure that the contents of the flask are well mixed If not,
superheating may result, and the mixture may be blown out of the open end of the
condenser
7 1 1 If volatile orgamcs are present in the sample, use an allihn condenser and add the
sulfunc acid-silver sulfate solution through the condenser, while cooling the flask,
to reduce loss by volatilization
7 2 Apply heat to the flask and reflux for 2 hours For some waste waters, the 2-hour reflux
period is not necessary The time required to give the maximum oxidation for a
wastewater of constant or known composition may be determined and a shorter period of
refluxing may be permissible
7 3 Allow the flask to cool and wash down the condenser with about 25 ml of distilled water
If a round bottom flask has been used, transfer the mixture to a 500 ml Erlenmeyer flask,
washing out the reflux flask 3 or 4 times with distilled water Dilute the acid solution to
about 300 ml with distilled water and allow the solution to cool to about room
temperature Add 8 to 10 drops of ferrom indicator (6 6) to the solution and titrate the
excess dichromate with 0 25 N ferrous ammonium sulfate (6 4) solution to the end point
The color change will be sharp, changing from a blue-green to a reddish hue
7 4 Blank-Simultaneously run a blank determination following the details given in (7 1) and
(7 2), but using low COD water in place of sample
Calculation
8 1 Calculate the COD in the sample in mg/1 as follows
COD, mg/liter = (A - B)N x 8,000
S
where
A = milhliters of Fe(NH4)2(SO4)2 solution required for titration of the blank,
B = milhliters of Fe(NH4)2 (SO4)2 solution required for titration of the sample,
N = normality of the Fe(NH4)2(SO4)2 solution, and
S = milhliters of sample used for the test
9 Precision and Accuracy
9 1 Eighty-six analysts m fifty-eight laboratories analyzed a distilled water solution
containing oxidizable organic material equivalent to 270 mg/1 COD The standard
deviation was ±17 76 mg/1 COD with an accuracy as percent relative error (bias) of
-4 7% (EPA Method Research Study 3)
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 550,
Method 508 (1975)
2 Annual Book of ASTM Standards, Part 31, "Water", Standard D1252-67, p 473 (1976)
410 1-3
-------
CHEMICAL OXYGEN DEMAND
Method 410.2 (Titrimetric, Low Level)
STORET NO. 00335
1 Scope and Application
1 1 The scope of this modification of the Chemical Oxygen Demand (COD) test is the same
as for the high level test It is applicable to the analysis of surface waters, domestic and
industrial wastes with low demand characteristics
1 2 This method (low level) is applicable foi samples having a COD in the range of 5-50
mg/1 COD
2 Summary of Method
2 1 Organic and oxidizable inorganic substances in an aqueous sample are oxidized by
potassium dichromate solution in 50 percent (by volume) sulfunc acid in solution The
excess dichromate is titrated with standard ferrous ammonium sulfate using
orthophenanthrolme ferrous complex (ferrom) as an indicator
3 Sampling and Preservation
3 1 Collect the samples in glass bottles, if possible Use of plastic containers is permissible if it
is known that no organic contaminants are present in the containers
3 2 Biologically active samples should be tested as soon as possible Samples containing
settleable material should be well mixed, preferably homogenized, to permit removal of
representative ahquots
3 3 Samples should be preserved with sulfunc acid to a pH < 2 and maintained at 4°C until
analysis
4 Interferences
4 1 Traces of organic material either from the glassware or atmosphere may cause a gross,
positive error
411 Extreme care should be exercised to avoid inclusion of organic materials in the
distilled water used for reagent preparation or sample dilution
412 Glassware used in the test should be conditioned by running blank procedures to
eliminate traces of organic material
4 2 Volatile materials may be lost when the sample temperature rises during the sulfunc acid
addition step
4 3 Chlorides are quantitatively oxidized by dichromate and represent a positive
interference Mercunc sulfate is added to the digestion flask to complex the chlondes,
thereby effectively eliminating the interference on all but bnne and estuanne samples
5 Apparatus
5 1 Reflux apparatus Glassware should consist of a 500 ml Erlenmeyer flask or a 300 ml
round bottom flask made of heat-resistant glass connected to a 12 inch Alhhn condenser
Issued 1971
Editorial revision 1974 and 1978
4102-1
-------
by means of a ground glass joint Any equivalent reflux apparatus may be substituted
provided that a ground-glass connection is used between the flask and the condenser
Reagents
6 1 Distilled water Special precautions should be taken to insure that distilled water used in
this test be low m organic matter
6 2 Standard potassium dichromate solution (0 025 N) Dissolve 12 259 g K2Cr2O7, primary
standard grade, previously dried at 103°C for two hours, m distilled water and dilute to
1000 ml Mix this solution thoroughly then dilute 100 0 ml to 1000 ml with distilled
water.
6 3 Sulfunc acid reagent Cone H2SO4 containing 23 5g silver sulfate, Ag2SO4, per 4 09kg
bottle (With continuous stirring, the silver sulfate may be dissolved m about 30
minutes )
6 4 Standard ferrous ammonium sulfate (0 025 N) Dissolve 98 g of Fe(NH4)2(SO4)2«6H2O in
distilled water Add 20 ml of cone H2SO4 (6 8), cool and dilute to 1 liter Dilute 100 ml of
this solution to 1 liter with distilled water This solution must be standardized daily
against K2Cr2O7 solution
6 4 1 Standardization To approximately 200 ml of distilled water add 25 0 ml of 0 025 N
K2Cr2O7 (6 2) solution Add 20 ml of H2SO4 (6 8) and cool Titrate with ferrous
ammonium sulfate (6 4) using 3 drops of ferroin indicator (6 6) The color change
is sharp, going from blue-green to reddish-brown
K,Cr2O7)(0 025)
ml Fe (NH4)2 (SO4)2
65 Mercuric sulfate Powdered HgSO4
6 6 Phenanthrohne ferrous sulfate (ferroin) indicator solution Dissolve 1 48 g of 1-10
(ortho)phenanthrolme monohydrate, together with 0 70 g of FeSO4»7H2O in 100 ml of
water This indicator may be purchased already prepared
6 7 Silver sulfate Powdered Ag2SO4
6.8 Sulfunc acid (sp gr 1 84) Concentrated H2SO4
Procedure
7 1 Place several boiling stones m the reflux flask, followed by 50 0 ml of sample or an
aliquot diluted to 50 0 ml and 1 g of HgSO4 (6 5) Add 5 0 ml cone H2SO4 (6 8), swirl
until the mercuric sulfate has dissolved Place reflux flask m an ice bath and slowly add,
with swirling, 25 0 ml of 0 025 N K2Cr2O7 (6 2) Now add 70 ml of sulfunc acid-silver
sulfate solution (6 3) to the cooled reflux flask, again using slow addition with swirling
motion
Caution Care must be taken to assure that the contents of the flask are well mixed If not,
superheating may result, and the mixture may be blown out of the open end of the
condenser
410 2-2
-------
71,1 If volatile orgamcs are present in the sample, use an Allihn condenser and add the
sulfunc acid-silver sulfate solution through the condenser, while cooling the flask,
to reduce loss by volatilization
7 2 Apply heat to the flask and reflux for 2 hours For some waste waters, the 2-hour reflux
period is not necessary The time required to give the maximum oxidation for a
wastewater of constant or known composition may be determined and a shorter period of
refluxing may be permissible
7 3 Allow the flask to cool and wash down the condenser with about 25 ml of distilled water
If a round bottom flask has been used, transfer the mixture to a 500 ml Erlenmeyer flask,
washing out the reflux flask 3 or 4 times with distilled water Dilute the acid solution to
about 300 ml with distilled water and allow the solution to cool to about room
temperature Add 8 to 10 drops of ferroin indicator (6 6) to the solution and titrate the
excess dichromate with 0 025 N ferrous ammonium sulfate (6 4) solution to the end
point The color change will be sharp, changing from a blue-green to a reddish hue
7 4 Blank—Simultaneously run a blank determination following the details given in (7 1)
and (7 2), but using low COD water in place of sample
Calculation
8 1 Calculate the COD in the sample in mg/1 as follows
COD, mg/1 = (A ~ B)N x 8,000
O
where
A = millihters of Fe(NH4)2(SO4)2 solution required for titration of the blank,
B = millihters of Fe(NH4)2(SO4)2 solution required for titration of the sample,
N = normality of the Fe(NH4)2(SO4)2 solution, and
S = millihters of sample used for the test
Precision and Accuracy
9 1 Eighty-six analysts in fifty-eight laboratories analyzed a distilled water solution
containing oxidizable organic material equivalent to 12 3 mg/1 COD The standard
deviation was ±4 15 mg/1 COD with an accuracy as percent relative error (bias) of
0 3% (EPA Method Research Study 3 )
410 2-3
-------
CHEMICAL OXYGEN DEMAND
Method 410.3 (Titrimetric, High Level for Saline Waters)
STORET NO. 00340
Scope and Application
1 1 When the chloride level exceeds 1000 mg/1 the minimum accepted value for the COD
will be 250 mg/1 COD levels which fall below this value are highly questionable because
of the high chloride correction which must be made
Summary of Method
2 1 Organic and oxidizable inorganic substances in an aqueous sample are oxidized by
potassium dichromate solution in 50 percent (by volume) sulfunc acid solution The
excess dichromate is titrated with standard ferrous ammonium sulfate using
orthophenanthrolme ferrous complex (ferroin) as an indicator
Sample Handling and Preservation
3 1 Collect the samples in glass bottles, if possible Use of plastic containers is permissible if it
is known that no organic contaminants are present in the containers
3 2 Biologically active samples should be tested as soon as possible Samples containing
settleable material should be well mixed, preferably homogenized, to permit removal of
representative ahquots
3 3 Samples should be preserved with sulfunc acid to a pH < 2 and maintained at 4°C until
analysis
Interferences
4 1 Traces of organic material either from the glassware or atmosphere may cause a gross,
positive error
411 Extreme care should be exercised to avoid inclusion of organic materials in the
distilled water used for reagent preparation or sample dilution
412 Glassware used in the test should be conditioned by running blank procedures to
eliminate traces of organic material
4 2 Volatile materials may be lost when the sample temperature rises during the sulfunc acid
addition step
43 Chlorides are quantitatively oxidized by dichromate and represent a positive
interference A chloride correction is made using the procedure outlined in 7 7 of this
method
Apparatus
5 1 Reflux apparatus Glassware should consist of a 500 ml Erlenmeyer flask or a 300 ml
round bottom flask made of heat-resistant glass connected to a 12 inch Allihn condenser
by means of a ground glass joint Any equivalent reflux apparatus may be substituted
provided that a ground-glass connection is used between the flask and the condenser
Issued 1971
Editorial revision 1978
4103-1
-------
Reagents
6 1 Standard potassium dichromate solution, (0 25 N) Dissolve 12 2588 g of K2Cr2O7,
primary standard grade, previously dried for 2 hours at 103°C m water and dilute to 1000
ml
6 2 Sulfunc acid reagent Cone H2SO4 containing 23 5 g silver sulfate, Ag2SO4, per 4 09kg
bottle (With continuous stirring, the silver sulfate may be dissolved m about 30
minutes )
6 3 Standard ferrous ammonium sulfate, 0 250 N Dissolve 98 g of Fe(NH4)2(SO4)2«6H2O in
distilled water Add 20 ml of cone H2SO4, (6 7), cool and dilute to 1 liter This solution
must be standardized against the standard potassium dichromate solution (61) daily
631 Standardization Dilute 25 0 ml of standard dichromate solution (6 1) to about 250
ml with distilled water Add 20 ml cone sulfunc acid (6 7) Cool, then titrate with
ferrous ammonium sulfate titrant (6 3), using 10 drops of ferroin indicator (6 5)
Normality =
dluy
ml Fe(NH4)2 (S04)2
6 4 Mercuric sulfate Powdered HgSO4
6 5 Phenanthrolme ferrous sulfate (ferroin) indicator solution Dissolve 1 48 g of 1-10-
(ortho) phenanthrohne monohydrate, together with 0 70 g of FeSO4»7H2O m 100 ml of
water This indicator may be purchased already prepared
66 Silver sulfate Powdered Ag2SO4
6 7 Sulfunc acid (sp gr 1 84) Concentrated H2SO4
7. Procedure
7 1 Pipet a 50 0 ml aliquot of sample not to exceed 800 mg/1 of COD into a 500 ml, flat
bottom, Erlenmeyer flask Add HgSO4 (6 4) in the ratio of 10 mg to 1 mg chloride, based
upon the mg of chloride in the sample aliquot and 5 ml of sulfunc acid (6 7) Swirl until
all the mercunc sulfate has dissolved Add 25 0 ml of 0 25N K2Cr2O7 (6 1) Carefully add
70 ml of sulfunc acid-silver sulfate solution (6 2) and gently swirl until the solution is
thoroughly mixed Glass beads should be added to the reflux mixture to prevent
bumping, which can be severe and dangerous
Caution The reflux mixture must be thoroughly mixed before heat is applied If this is
not done, local heating occurs in the bottom of the flask, and the mixture may be blown
out of the condenser
711 If volatile organics are present in the sample, use an Allihn condenser and add the
sulfunc acid-silver sulfate solution through the condenser, while cooling the flask,
to reduce loss by volatilization
7 2 Attach the flask to the condenser and reflux the mixture for two hours
7 3 Cool, and wash down the interior of the condenser with 25 ml of distilled water
Disconnect the condenser and wash the flask and condenser joint with 25 ml of distilled
water so that the total volume is 350 ml Cool to room temperature
410 3-2
-------
7 4 Titrate with standard ferrous ammonium sulfate (6 3) using 10 drops of ferrom (6 5)
indicator (This amount must not vary from blank, sample and standardization ) The
color change is sharp, going from blue-green to reddish-brown and should be taken as the
end point although the blue-green color may reappear within minutes
7 5 Run a blank, using 50 ml of distilled water in place of the sample together with all
reagents and subsequent treatment
7 6 For COD values greater than 800 mg/1, a smaller aliquot of sample should be taken,
however, the volume should be readjusted to 50 ml with distilled water having a chloride
concentration equal to the sample
7 7 Chloride correction"' Prepare a standard curve of COD versus mg/1 of chloride, using
sodium chloride solutions of varying concentrations following exactly the procedure
outlined The chloride interval, as a minimum should be 4000 mg/1 up to 20,000 mg/1
chloride Lesser intervals of greater concentrations must be run as per the requirements
of the data, but in no case must extrapolation be used
Calculation
mg/1 COD = [(A - B)C X 8.000] - SOD
ml of sample
where
A = ml Fe(NH4)2(SO4)2 for blank,
B = ml Fe(NH4)2(SO4)2 for sample,
C = normality of Fe(NH4)2(SO4)2,
D = chloride correction from curve (step 7 7)
12 = compensation factor to account for the extent of chloride oxidation which is dissimilar in
systems containing organic and non-organic material
Precision and Accuracy
9 1 Precision and accuracy data are not available at this time
Bibliography
Burns, E R , Marshall, C , Journal WPCF, Vol 37, p 1716-1721 (1965)
410 3-3
-------
CHEMICAL OXYGEN DEMAND
Method 410.4 (Colorimetric, Automated; Manual)
STORET NO. 00340
1 Scope and Application
1 1 This method covers the determination of COD in surface waters, domestic and industrial
wastes
1 2 The applicable range of the automated method is 3-900 mg/1 and the range of the
manual method is 20 to 900 mg/1
2 Summary of Method
2 1 Sample, blanks and standards in sealed tubes are heated m an oven or block digester m
the presence of dichromate at 150°C Aftei two hours, the tubes are removed from the
oven or digester, cooled and measured spectrophotometncally at 600 nm
3 Sample Handling and Preservation
3 1 Collect the samples in glass bottles if possible Use of plastic containers is permissible if it
is known that no organic contaminants are present in the containers
3 2 Samples should be preserved with sulfunc acid to a pH < 2 and maintained at 4°C until
analysis
4 Interferences
4 1 Chlorides are quantitatively oxidized by dichromate and represent a positive
interference Mercuric sulfate is added to the digestion tubes to complex the chlorides
5 Apparatus
5 1 Drying oven or block digestor, 150°C
5 2 Corning culture tubes, 16 x 100 mm or 25 x 150 mm with Teflon lined screw cap
5 3 Spectrophotometer or Techmcon Auto Analyzer
5 4 Muffle furnace, 500°C
6 Reagents
6 1 Digestion solution Add 10 2 g K2Cr2O7, 167 ml cone H2SO4 and 33 3 g HgSO4 to 500 ml
of distilled water, cool and dilute to 1 liter
6 2 Catalyst solution Add 22 g Ag2SO4 to a 4 09kg bottle of cone H2SO4 Stir until
dissolved
6 3 Sampler wash solution Add 500 ml of cone H2SO4 to 500 ml of distilled water
6 4 Stock potassium acid phthalate Dissolve 0 850 g m 800 ml of distilled water and dilute to
1 liter 1 ml = 1 mg COD
641 Prepare a series of standard solutions that cover the expected sample
concentrations by diluting appropriate volumes of the stock standard
7 Procedure
7 1 Wash all culture tubes and screw caps with 20% H2SO4 before their first use to prevent
contamination Trace contamination may be removed from the tubes by igniting them in
a muffle oven at 500°C for 1 hour
Pending approval for Section 304(h), CWA
Issued 1978
4104-1
-------
72- Automated
721 Add 2 5 ml of sample to the 16 x 100 mm tubes
722 Add 1 5 ml of digestion solution (61) and mix
723 Add 3 5 ml of catalyst solution (6 2) carefully down the side of the culture tube
724 Cap tightly and shake to mix layers
725 Process standards and blanks exactly as the samples
726 Place in oven or block digester at 150°C for two hours
727 Cool, and place standards in sampler in order of decreasing concentration
Complete filling sampler tray with unknown samples
728 Measure color intensity on AutoAnalyzer at 600 nm
7 3 Manual
731 The following procedure may be used if a larger sample is desired or a
spectrophotometer is used in place of an AutoAnalyzer
732 Add 10 ml of sample to 25 x 150 mm culture tube
7.33 Add 6 ml of digestion solution (6 1) and mix
734 Add 14 ml of catalyst solution (6 2) down the side of culture tube
735 Cap tightly and shake to mix layers
736 Place in oven or block digester at 150°C for 2 hours
737 Cool, allow any precipitate to settle and measure intensity in spectrophotometer at
600 nm Use only optically matched culture tubes or a single cell for spectro-
photometnc measurement
8. Calculation
8 1 Prepare a standard curve by plotting peak height or percent transmittance against known
concentrations of standards
8 2 Compute concentration of samples by comparing sample response to standard curve
9 Precision and Accuracy
9 1 Precision and accuracy data are not available at this time
Bibliography
1 Jirka, A M , and M J Carter, "Micro-Serm-Automated Analysis of Surface and Wastewaters
for Chemical Oxygen Demand " Anal Chem 47 1397, (1975)
410 4-2
-------
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4104-3
-------
OIL AND GREASE, TOTAL, RECOVERABLE
Method 413.1 (Gravimetric, Separatory Funnel Extraction)
STORET NO. 00556
1 Scope and Application
1 1 This method includes the measurement of fluorocarbon-113 extractable matter from
surface and saline waters, industrial and domestic wastes It is applicable to the
determination of relatively non-volatile hydrocarbons, vegetable oils, animal fats, waxes,
soaps, greases and related matter
1 2 The method is not applicable to measurement of light hydrocarbons that volatilize at
temperatures below 70°C Petroleum fuels from gasoline through #2 fuel oils are
completely or partially lost in the solvent removal operation
1 3 Some crude oils and heavy fuel oils contain a significant percentage of residue-type
materials that are not soluble in fluorocarbon-113 Accordingly, recoveries of these
materials will be low
1 4 The method covers the range from 5 to 1000 mg/1 of extractable material
2 Summary of Method
2 1 The sample is acidified to a low pH ( < 2) and serially extracted with fluorocarbon-113 in
a separatory funnel The solvent is evaporated from the extract and the residue weighed
3 Definitions
3 1 The definition of oil and grease is based on the procedure used The nature of the oil
and/or grease, and the presence of extractable non-oily matter will influence the material
measured and interpretation of results
4 Sampling and Storage
41 A representative sample of 1 liter volume should be collected in a glass bottle If analysis
is to be delayed for more than a few hours, the sample is preserved by the addition of 5 ml
HC1 (6 1) at the time of collection and refngeiated at 4°C
4 2 Because losses of grease will occur on sampling equipment, the collection of a composite
sample is impractical Individual portions collected at prescribed time intervals must be
analyzed separately to obtain the average concentration over an extended period
5 Apparatus
5 1 Separatory funnel, 2000 ml, with Teflon stopcock
5 2 Vacuum pump, or other source of vacuum
5 3 Flask, boiling, 125 ml (Corning No 4100 or equivalent)
5 4 Distilling head, Claisen or equivalent
5 5 Filter paper, Whatman No 40,11 cm
6 Reagents
6 1 Hydrochloric acid, 1 1 Mix equal volumes of cone HC1 and distilled water
Approved for NPDES
Issued 1974
Editorial revision 1978
413 1-1
-------
62 Flurocarbon-113,(l,l,2-tnchloro-l,2,2-tnfluoroethane),b p 48°C
6 3 Sodium sulfate, anhydrous crystal
7. Procedure
7 1 Mark the sample bottle at the water meniscus for later determination of sample volume
If the sample was not acidified at time of collection, add 5 ml hydrochloric acid (6 1) to
the sample bottle After mixing the sample, check the pH by touching pH-sensitive paper
to the cap to insure that the pH is 2 or lower Add more acid if necessary
7 2 Pour the sample into a separatory funnel
7 3 Tare a boiling flask (pre-dned in an oven at 103°C and stored m a desiccator)
7 4 Add 30 ml fluorocarbon-113 (6 2) to the sample bottle and rotate the bottle to rinse the
sides Transfer the solvent into the separatory funnel Extract by shaking vigorously for 2
minutes Allow the layers to separate, and filter the solvent layer into the flask through a
funnel containing solvent moistened filter paper
NOTE: An emulsion that fails to dissipate can be broken by pouring about 1 g sodium
sulfate (6 3) into the filter paper cone and slowly draining the emulsion through the salt
Additional 1 g portions can be added to the cone as required
7 5 Repeat (7 4) twice more, with additional portions of fresh solvent, combining all solvent
in the boiling flask
7 6 Rinse the tip of the separatory funnel, the filter paper, and then the funnel with a total of
10-20 ml solvent and collect the rinsings in the flask
7.7 Connect the boiling flask to the distilling head and evaporate the solvent by immersing
the lower half of the flask in water at 70°C Collect the solvent for reuse A solvent blank
should accompany each set of samples
7 8 When the temperature in the distilling head reaches 50°C or the flask appears dry remove
the distilling head Sweep out the flask for 15 seconds with air to remove solvent vapor by
inserting a glass tube connected to a vacuum source Immediately remove the flask from
the heat source and wipe the outside to remove excess moisture and fingerprints
7 9 Cool the boiling flask in a desiccator for 30 minutes and weigh
8 Calculation
•Q T3
8.1 mg/1 total oil and grease = ...
where
R = residue, gross weight of extraction flask minus the tare weight, in milligrams
B = blank determination, residue of equivalent volume of extraction solvent, in
milligrams
V = volume of sample, determined by refilling sample bottle to calibration line and
correcting for acid addition if necessary, in liters
413 1-2
''1"
-------
9 Precision and Accuracy
9 1 The two oil and grease methods in this manual were tested by a single laboratory (EMSL)
on sewage This method determined the oil and grease level in the sewage to be 126
mg/1 When 1 liter portions of the sewage were dosed with 14 0 mg of a mixture of #2
fuel oil and Wesson oil, the recovery was 93% with a standard deviation of ±0 9 mg/1
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 515,
Method 502A, (1975)
2 Blum, K A , and Taras, M J , "Determination of Emulsifying Oil m Industrial Wastewater",
JWPCF Research Suppl 40,R404(1968)
413 1-3
-------
OIL AND GREASE, TOTAL RECOVERABLE
Method 413.2 (Spectrophotometric, Infrared)
STORET NO. 00560
1 Scope and Application
1 1 This method includes the measurement of fluorocarbon-113 extractable matter from
surface and saline waters, industrial and domestic wastes It is applicable to the
determination of hydrocarbons, vegetable oils, animal fats, waxes, soaps, greases and
related matter
1 2 The method is applicable to measurement of most light petroleum fuels, although loss of
about half of any gasoline present during the extraction manipulations can be expected
1 3 The method covers the range from 0 2 to 1000 mg/1 of extractable material
1 4 While this method can be used to obtain an estimate of the oil and grease that would be
measured gravimetncally, in many cases the estimate more accurately describes the
parameter, as it will measure volatiles more effectively and is not susceptible to
interferences such as extractable sulfur It can be used with the Petroleum Hydrocarbon
procedure to obtain an oil and grease value and a petroleum hydrocarbon value on the
same sample
2 Summary of Method
2 1 The sample is acidified to a low pH ( < 2) and extracted with fluorocarbon-113 The oil
and grease is determined by comparison of the infrared absorbance of the sample extract
with standards
3 Definitions
3 1 The definition of oil and grease is based on the procedure used The source of the oil
and/or grease, and the presence of extractable non-oily matter will influence the material
measured and interpretation of results
4 Sampling and Storage
41 A representative sample of 1 liter volume should be collected in a glass bottle If analysis
is to be delayed for more than a few hours, the sample is preserved by the addition of 5 ml
HC1 (6 1) at the time of collection and refrigerated at 4°C
4 2 Because losses of grease will occur on sampling equipment, the collection of a composite
sample is impractical Individual portions collected at prescribed time intervals must be
analyzed separately to obtain the average concentration over an extended period
5 Apparatus
5 1 Separatory funnel, 2000 ml, with Teflon stopcock
5 2 Infrared spectrophotometer, scanning Non-scanning instruments may also be used but
can be subject to positive interferences in complex chemical wastewaters
5 3 Cells, 10 mm, 50 mm, and 100 mm path length, sodium chloride or infrared grade glass
5 4 Filter paper, Whatman No 40,11 cm
Issued 1974
Editorial revision 1978
413 2-1
-------
6 Reagents
6 1 Hydrochloric acid, 1 1 Mix equal volumes of cone HC1 and distilled water
62 Fluorocarbon-113, (l,l,2-tnchloro-l,2,2-tnfluoroethane),b p 48°C
6 3 Sodium sulfate, anhydrous crystal
6 4 Calibration mixtures
641 Reference oil Pipet 15 0 ml n-hexadecane, 15 0 ml isooctane, and 100 ml
chlorobenzene into a 50 ml glass stoppered bottle Maintain the integrity of the
mixture by keeping stoppered except when withdrawing ahquots
642 Stock standard Pipet 1 0 ml reference oil (6 4 1) into a tared 200 ml volumetric
flask and immediately stopper Weigh and dilute to volume with fluorocarbon-113
643 Working standards Pipet appropriate volumes of stock standard (6 4 2) into 100
ml volumetric flasks according to the cell pathlength to be used Dilute to volume
with fluorocarbon-113 Calculate concentration of standards from the stock
standard
7. Procedure
7 1 Mark the sample bottle at the water meniscus for later determination of sample volume
If the sample was not acidified at time of collection, add 5 ml hydrochloric acid (6 1) to
the sample bottle After mixing the sample, check the pH by touching pH-sensitive paper
to the cap to insure that the pH is 2 or lower Add more acid if necessary
7 2 Pour the sample into a separatory funnel
7.3 Add 30 ml fluorocarbon-113 (6 2) to the sample bottle and rotate the bottle to rinse the
sides Transfer the solvent into the separatory funnel Extract by shaking vigorously for 2
minutes Allow the layers to separate
7 4 Filter the solvent layer into a 100 ml volumetric flask through a funnel containing
solvent-moistened filter paper
NOTE: An emulsion that fails to dissipate can be broken by pouring about 1 g sodium
sulfate (6 3) into the filter paper cone and slowly draining the emulsion through the salt
Additional 1 g portions can be added to the cone as required
7 5 Repeat (7 3 and 7 4) twice more with 30 ml portions of fresh solvent, combining all
solvent in the volumetric flask
7 6 Rinse the tip of the separatory funnel, filter paper, and the funnel with a total of 5-10 ml
fluorocarbon-113 and collect the rinsings in the flask Dilute the extract to 100 ml, and
stopper the flask
7 7 Select appropriate working standards and cell pathlength according to the following
table of approximate working ranges
Pathlength Range
10 mm 2-40 mg
50 mm 04-8 mg
100 mm 0 1-4 mg
7 8 Scan standards and samples from 3200 cm"1 to 2700 cm"1 with fluorocarbon-113 in the
reference beam and record the results on absorbance paper The absorbances of samples
413 2-2
-------
and standards are measured by constructing a straight baseline over the range of the scan
and measuring the absorbance of the peak maximum at 2930 cm"1 and subtracting the
baseline absorbance at that point For an example of a typical oil spectrum and baseline
construction, see Gruenfeld<3) Non-scanning instruments should be operated according
to manufacturer's instructions, although calibration must be performed using the
standards described above (6 4) If the absorbance exceeds 0 8 for a sample, select a
shorter pathlength or dilute as required
7 9 Use a calibration plot of absorbance vs mg oil prepared from the standards to determine
the mg oil in the sample solution
Calculation
8 1 mg/1 total oil and grease = R * D
where
R = oil in solution, determined from calibration plot, in milligrams
D = extract dilution factor, if used
V = volume of sample, determined by refilling sample bottle to calibration line and
correcting for acid addition if necessary, in liters
9 Precision and Accuracy
9 1 The two oil and grease methods in this manual were tested by a single laboratory (EMSL)
on sewage This method determined the oil and grease level in the sewage to be 17 5
mg/1 When 1 liter portions of the sewage were dosed with 14 0 mg of a mixture of #2
fuel oil and Wesson oil, the recovery was 99% with a standard deviation of ± 1 4 mg/1
Bibliography
1 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 516,
Method 502B, (1975)
2 American Petroleum Institute, "Manual on Disposal of Refinery Wastes", Vol IV, Method
733-58(1958)
3 Gruenfeld, M, "Extraction of Dispersed Oils from Water for Quantitative Analysis by
Infrared Spectroscopy", Environ Sci Technol 7,636(1973)
413 2-3
-------
ORGANIC CARBON, TOTAL
Method 415.1 (Combustion or Oxidation)
STORET NO. Total 00680
Dissolved 00681
Scope and Application
1 1 This method includes the measurement of organic carbon in drinking, surface and saline
waters, domestic and industrial wastes Exclusions are noted under Definitions and
Interferences
1 2 The method is most applicable to measurement of organic carbon above 1 mg/1
Summary of Method
2 1 Organic carbon in a sample is converted to carbon dioxide (CO2) by catalytic combustion
or wet chemical oxidation The CO2 formed can be measured directly by an infrared
detector or converted to methane (CH4) and measured by a flame lomzation detector
The amount of CO2 or CH4 is directly proportional to the concentration of carbonaceous
material in the sample
Definitions
3 1 The carbonaceous analyzer measures all of the carbon in a sample Because of various
properties of carbon-containing compounds in liquid samples, preliminary treatment of
the sample prior to analysis dictates the definition of the carbon as it is measured Forms
of carbon that are measured by the method are
A) soluble, nonvolatile organic carbon, for instance, natural sugars
B) soluble, volatile organic carbon, for instance, mercaptans
C) insoluble, partially volatile carbon, for instance, oils
D) insoluble, particulate carbonaceous materials, for instance, cellulose fibers
E) soluble or insoluble carbonaceous materials adsorbed or entrapped on insoluble
inorganic suspended matter, for instance, oily matter adsorbed on silt particles
3 2 The final usefulness of the carbon measurement is in assessing the potential oxygen-
demanding load of organic material on a receiving stream This statement applies
whether the carbon measurement is made on a sewage plant effluent, industrial waste, or
on water taken directly from the stream In this light, carbonate and bicarbonate carbon
are not a part of the oxygen demand in the stream and therefore should be discounted in
the final calculation or removed prior to analysis The manner of preliminary treatment
of the sample and instrument settings defines the types of carbon which are measured
Instrument manufacturer's instructions should be followed
Approved for NPDES
Issued 1971
Editorial revision 1974
415 1-1
-------
4. Sample Handling and Preservation
4 1 Sampling and storage of samples in glass bottles is preferable Sampling and storage in
plastic bottles such as conventional polyethylene and cubitamers is permissible if it is
established that the containers do not contribute contaminating organics to the samples
NOTE 1: A brief study performed in the EPA Laboratory indicated that distilled water
stored in new, one quart cubitamers did not show any increase in organic carbon after
two weeks exposure
4 2 Because of the possibility of oxidation or bacterial decomposition of some components of
aqueous samples, the lapse of time between collection of samples and start of analysis
should be kept to a rrummum Also, samples should be kept cool (4°C) and protected
from sunlight and atmospheric oxygen
43 In instances where analysis cannot be performed within two hours (2 hours) from time of
sampling, the sample is acidified (pH < 2) with HC1 or H2SO4
5 Interferences
5 1 Carbonate and bicarbonate carbon represent an interference under the terms of this test
and must be removed or accounted for in the final calculation
5 2 This procedure is applicable only to homogeneous samples which can be injected into the
apparatus reproducibly by means of a microhter type syringe or pipette The openings of
the syringe or pipette limit the maximum size of particles which may be included in the
sample
6 Apparatus
6 1 Apparatus for blending or homogenizing samples Generally, a Wanng-type blender is
satisfactory
6 2 Apparatus for total and dissolved organic carbon
6 2 1 A number of companies manufacture systems for measuring carbonaceous
material in liquid samples Considerations should be made as to the types of
samples to be analyzed, the expected concentration range, and forms of carbon to
be measured
622 No specific analyzer is recommended as superior
7, Reagents
7 1 Distilled water used in preparation of standards and for dilution of samples should be
ultra pure to reduce the carbon concentration of the blank Carbon dioxide-free, double
distilled water is recommended Ion exchanged waters are not recommended because of
the possibilities of contamination with organic materials from the resins
7 2 Potassium hydrogen phthalate, stock solution, 1000 mg carbon/liter Dissolve 0 2128 g
of potassium hydrogen phthalate (Primary Standard Grade) in distilled water and dilute
to 100 0 ml
NOTE 2- Sodium oxalate and acetic acid are not recommended as stock solutions
7 3 Potassium hydrogen phthalate, standard solutions Prepare standard solutions from the
stock solution by dilution with distilled water
7 4 Carbonate-bicarbonate, stock solution, 1000 mg carbon/liter Weigh 0 3500 g of sodium
bicarbonate and 0 4418 g of sodium carbonate and transfer both to the same 100 ml
volumetric flask Dissolve with disulled water
415 1-2
-------
7 5 Carbonate-bicarbonate, standard solution Prepare a series of standards similar to step
73
NOTE 3: This standard is not required by some instruments
7 6 Blank solution Use the same distilled water (or similar quality water) used for the
preparation of the standard solutions
8 Procedure
8 1 Follow instrument manufacturer's instructions for calibration, procedure, and
calculations
8 2 For calibration of the instrument, it is recommended that a series of standards
encompassing the expected concentration range of the samples be used
9 Precision and Accuracy
9 1 Twenty-eight analysts in twenty-one laboratories analyzed distilled water solutions
containing exact increments of oxidizable organic compounds, with the following results
Increment as Precision as Accuracy as
TOC Standard Deviation Bias, Bias,
mg/liter TOC, mg/liter _% mg/hter
49 393 +1527 +075
107 832 +101 +108
(FWPCA Method Study 3, Demand Analyses)
Bibliography
1 Annual Book of ASTM Standards, Part 31, "Water", Standard D 2574-79, p 469 (1976)
2 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 532,
Method 505, (1975)
415 1-3
-------
United States
Environmental Protection
Agency
Environmental Monitoring and
Support Laboratory
Cincinnati OH 45268
Research and Development
&EPA
Test Method
Organic Carbon, Total
(low level)
(UV promoted, persulfate
oxidation)—Method 415.2
1 Scope and Application
1 1 This method covers the
determination of total organic carbon
in drinking water and other waters
subject to the limitations in 1 3 and
5 1
1 2 This instrument is designed for
a two-step operation to distinguish
between purgeable and nonpurgeable
organic carbon These separate values
are not pertinent to this method
1 3 This method is applicable only to
the carbonaceous matter which is
either soluble or has a particle size of
0 2 mm or less
1 4 The applicable range is from
approximately 50 yug/L to 10 mg /L
Higher concentrations may be
determined by sample dilution
2 Summary of Method
A sample is combined with 1 mL of
acidified persulfate reagent and
placed in a sparger The sample is
purged with helium which transfers
inorganic CO2 and purgeable organics
to a CO2 scrubber The CO2 is
removed with at least 99 9%
efficiency with a 2 5-mmute purge
The purgeable organics proceed
through a reduction system where the
gas stream is joined by hydrogen and
passed over a nickel catalyst which
converts the purgeable organic carbon
to methane The methane is
measured by a flame lomzation
detector The detector signal is
integrated and displayed as the
concentration of purgeable organic
carbon
The sample is then transferred to a
quartz ultraviolet reaction coil where
the nonpurgeable organics are
subjected to intense ultraviolet
illumination in the presence of the
acidified persulfate reagent The
nonpurgeables are converted to CO2
and transferred to a second sparger
where a helium purge transfers the
COa to the reduction system and into
the detector The signal is integrated,
added to the purgeable organic carbon
value and displayed as the
concentration of total organic carbon
3 Definitions
3 1 Total organic carbon measured
by this procedure is the sum of the
purgeable organic carbon and the
nonpurgeable organic carbon as
defined m 3 2 and 3 3
3 2 Purgeable organic carbon is the
organic carbon matter that is
transferred to the gas phase when the
sample is purged with helium and
which passes through the CO2
scrubber The definition is instrument-
condition dependent
3 3 Nonpurgeable organic carbon is
defined as that which remains after
removal of the purgeable organic
carbon from the sample containing
acidified persulfate reagent and which
4152-1
Dec 1982
-------
is converted to COt under the
instrument conditions
3.4 The system blank is the value
obtained in 8 2 for an irradiated,
recirculatod reagent distilled water
sample
4. Sample Handling and
•Preservation
4,1 Sampling and storage of
samples must be done in glass
bottles Caution Do not leave any
headspace in the sample bottle as
this may contribute to loss of
purgeable organics
4 2 Because of the possibility of
oxidation or bacterial decomposition of
some components of aqueous
samples, the lapse of time between
collection of samples and start of
analysis should be kept to a minimum
Also, samples should be kept cool
(4°C) and protected from sunlight and
atmospheric oxygen
4 3 When analysis cannot be
performed within two hours from time
of sampling, the sample should be
acidified to pH 2 with H2SO< Note
HCI should not be used because it is
converted to chlorine during the
analysis This causes damage to the
instrument
5. Interferences
5.1 If a sample is homogenized to
reduce the size of the paniculate
matter, the homogenizing may cause
loss of purgeable organic carbon, thus
yielding erroneously low results
6. Apparatus
6.1 Apparatus for blending or
homogenizing samples A household
blender or similar device that will
reduce particles in the sample to less
than 0 2 mm
6,2 Apparatus for Total Organic
Carbon* The essential components for
the apparatus used in this method
are A sparge assembly, flow
switching valves, a pyrolysis furnace,
quartz ultraviolet reactor coil, reducing
column, flame lonization detector,
electrometer and integrator This
method is based on the Dohrmann
Envirotech DC-54 Carbon Analyzer
Other Instruments having similar
performance characteristics may be
used
6 3 Sampling Devices Any
apparatus that will reliably transfer
10 mL of sample to the sparger A 50
mL glass syringe is recommended
when analyzing samples with easily
purgeable organics so as to minimize
losses
7 Reagents
7 1 Reagent Distilled Water
Distilled water used m preparation of
standards and for dilution of samples
should be ultra-pure to reduce the
magnitude of the blank Carbon
dioxide-free, double distilled water is
recommended The water should be
distilled from permanganate or be
obtained from a system involving
distillation and carbon treatment The
reagent distilled water value must be
compared to a system blank
determined on a recirculated distilled
water sample The total organic
carbon value of the reagent distilled
water should be less than 60/ug/L
Purgeable organic carbon values of
the reagent distilled water should be
less than
7 2 Potassium hydrogen phthalate,
stock solution 500 mg carbon/liter
Dissolve 1 063 g of potassium
hydrogen phthalate (Primary Standard
Grade) m reagent distilled water (7 1)
and dilute to 1 liter
7 3 Potassium hydrogen phthalate (2
mg/L) Pipet 4 mL of potassium
hydrogen phthalate stock solution
(7 2) into a one liter volumetric flask
and dilute to the mark with reagent
distilled water (71}
7 4 Potassium hydrogen phthalate (5
mg/L) Pipet 1 mL of potassium
hydrogen phthalate stock solution
(7 2) into a 100 mL volumetric flask
and dilute to the mark with reagent
distilled water (7 1)
7 5 Potassium hydrogen phthalate
(10 mg/L) Pipet 2 mL of potassium
hydrogen phthalate stock solution
(7 2) into a 100 mL volumetric flask
and dilute to the mark with reagent
distilled water (7 1)
7 6 Acidified Persulfate Reagent
Place 100 mL of reagent distilled
water (7 1 ) m a container Add 5 g of
potassium persulfate Add 5 g (3 mL)
of concentrated (85%) phosphoric
acid
7 7 Carbonate-bicarbonate, stock
solution, 1000 mg carbon/liter Place
0 3500 g of sodium bicarbonate and
0 441 8 g of sodium carbonate in a
100 mL volumetric flask Dissolve with
reagent distilled water (7 1) and dilute
to the mark
7 8 Carbonate-bicarbonate, standard
solution 50 mg/L Place 5 ml of the
carbonate-bicarbonate stock solution
m a 100 mL volumetric flask and
dilute to the mark with reagent
distilled water (7 1)
8 Procedure
8 1 Allow at least 30 minutes
warm-up time Leave instrument
console on continuously when m daily
use, except for the ultraviolet light
source, which should be turned off
when not m use for more than a few
hours
8 2 Adjust all gas flows,
temperatures and cycle times to
manufacturer s specifications Perform
the System Cleanup and Calibration
procedure m the manufacturer s
specifications each day Recirculate a
sample of irradiated distilled water
until two consecutive readings within
10% of each other are obtained
Record the last value for the system
blank This value is a function of the
total instrument operation and should
not vary significantly from previous
runs Reasons for significant changes
m the value should be identified
8 3 Check the effectiveness of the
COa scrubber by analyzing the
carbonate-bicarbonate standard
solution(7 8) Add 1 mL of acidified
persulfate reagent (7 6) to 50 mL of
the solution Transfer 10 mL of the
solution-with-reagent to the first
sparger and start the analysis cycle
No response, or a very minor reading,
should be obtained from this solution
8 4 Add 1 mL of acidified persulfate
reagent (7 6) to 50 mL of reagent
distilled water (7 1) blank, standards
7 3, 7 4, and 7 5 and the samples
8 5 Calibrate the analyzer as
follows
851 Run the reagent distilled water
(7 1) and 5 0 mg/L standard (7 4)
Transfer 10 mL of the solution-with-
reagent to the first sparger and start
analyzer cycle
Ignore the meter reading for the first
cycle
Transfer a second 10 mL of the
solution-with-reagent to the first
sparger and start the analysis cycle
Record the meter reading (see 9 1) of
the final carbon value for each of the
reagent distilled water (7 1) and the
standard (7 4)
If the meter reading is more than 25%
above or below the calculated value of
standard 7 4, reanalyze the standard
Dec 1982
4152-2
-------
and set the calibration within 25%
\Sb 4) reanalyze the system blank
and then begin 851 again If the
meter reading (see 9 1) is within 25%
of the calculated value, continue to
next step The calculated value is
defined in 8 5 2
852 Calculate the factor for the
deviation of the instrument reading
(see 9 1) for the standard (7 4) from
the calculated value by
standard reading -
calculated value _ FACTOR
calculated value
where the calculated value is that
value obtained by using the weight of
potassium hydrogen phthalate and
does not include the carbon
contributed by the reagent distilled
water (7 1) with which it has been
diluted
853 Calculate the adjusted reading
by
calculated value + (ROW - (FACTOR X
ROW)) = ADJUSTED READING
where ROW = mean reagent distilled
water (7 1) value
854 Push in CALIBRATE button
after READY light comes on and
adjust the SPAN control to the
ADJUSTED READING calculated m
853
8 6 Analyze the standards 7 3 and 7 5
in order to check the linearity of the
instrument at least once each day
Transfer 10 mL of the solution-with-
reagent to the first sparger and start
analyzer cycle
Ignore the meter reading for the first
cycle
Transfer a second 10 mL of the
solution-with-reagent to the first
sparger and start the analyzer cycle
Record the meter reading (see 9 1) of
the final carbon value for each of the
standards 7 3 and 7 5
The range of concentration used for
calibrating the instrument and
checking the linearity of the
instrument should be ascertained
from a knowledge of the range of
concentrations expected from the
samples Standards for lower ranges
can be prepared by diluting standards
72,73, and 7 4
Transfer 10 mL of the solution-with-
reagent to the first sparger and start
analyzer cycle
Ignore the meter reading for the first
cycle
Transfer a second 10 mL of the
solution-with-reagent to the first
sparger and start the analyzer cycle
Record the meter reading (see 9 1) of
the final carbon value for each of the
samples
9 Calculations
9 1 The values are read off the final
digital readout in fjg/L The system
blank reading obtained in 8 2 must be
subtracted from all reagent distilled
water, standard and sample readings
10 Precision and Accuracy
101 In a single laboratory (MERL)
using raw river water centrifuged
river wa'er drinking water and the
effluent from a carbon column which
had concentrations of 3 11, 3 10
1 79 and 0 07 mg/L total organic
carbon respectively the standard
deviations from ten replicates were
±0 13, ±0 03 ±0 02 and +0 02
mg/L respectively
102 In a single laboratory (MERL)
using potassium hydrogen phthalate
m distilled water at concentrations of
50 and 1 0 mg/L total organic carbon,
recoveries were 80% and 91%
respectively
Bibliography
1 Proposed Standard Method for
Purgeable and Nonpurgeable Organic
Carbon in Water (UV-promoted,
persulfate oxidation method) ASTM
Committee D-19, Task Group
19060203 (Chairman R J Joyce),
January 1978
2 Operating Instruction Dohrmann
Envirotech 3420 Scott Boulevard
Santa Clara California 95050
3 Takahashi, Y Ultra Low Level
TOC Analysis of Potable Waters
Presented at Water Quality
Technology Conference AWWA Dec
5-8 1976
8 7 Analyze the samples Transfer
10 mL of sample with reagent to the
first sparger and start the analysis
cycle
4152-3
Dec 1982
-------
PETROLEUM HYDROCARBONS, TOTAL RECOVERABLE
Method 418.1 (Spectrophotometric, Infrared)
STORET NO. 45501
1 Scope and Application
1 1 This method is for the measurement of fluorocarbon-113 extractable petroleum
hydrocarbons from surface and saline waters, industrial and domestic wastes
1 2 The method is applicable to measurement of light fuels, although loss of about half of any
gasoline present during the extraction manipulations can be expected
1 3 The method is sensitive to levels of 1 mg/1 and less, and may be extended to ambient
monitoring
2 Summary of Method
2 1 The sample is acidified to a low pH ( < 2) and serially extracted with fluorocarbon-113 in
a separatory funnel Interferences are removed with silica gel adsorbant Infrared
analysis of the extract is performed by direct comparison with standards
3 Definitions
31 As in the case of Oil and Grease, the parameter of Petroleum Hydrocarbons is defined by
the method The measurement may be subject to interferences and the results should be
evaluated accordingly
3 2 Oil and Grease is a measure of biodegradable animal greases and vegetable oils along
with the relative non-biodegradable mineral oils Petroleum hydrocarbons is the measure
of only the mineral oils Maximum information may be obtained using both methods to
measure and characterize oil and grease of all sources
4 Sampling and Storage
4 1 A representative sample of 1 liter volume should be collected in a glass bottle Because
losses of grease will occur on sampling equipment, the collection of a composite sample is
impractical The entire sample is consumed by this test, no other analyses may be
performed using ahquots of the sample
42 A delay between sampling and analysis of greater than 4 hours requires sample
preservation by the addition of 5 ml HC1 (6 1) A delay of greater than 48 hours also
requires refrigeration for sample preservation
5 Apparatus
5 1 Separatory funnel, 2000 ml, with Teflon stopcock
5 2 Filter paper, Whatman No 40, 11 cm
5 3 Infrared spectrophotometer, scanning or fixed wavelength, for measurement around
2950cm-'
5 4 Cells, 10 mm, 50 mm, and 100 mm pathlength, sodium chloride or infrared grade glass
5 5 Magnetic stirrer, with Teflon coated stirring bars
6 Reagents
6 1 Hydrochloric acid, 1 1 Mix equal volumes of cone HC1 and distilled water
Issued 1978
418 1-1
-------
6 2 Fluorocarbon-113,(1,l,2-tnchloro-l,2,2-tnfluroethane), b p 48°C
6 3 • Sodium sulfate, anhydrous crystal
6 4 Silica gel, 60-200 mesh, Davidson Grade 950 or equivalent Should contain 1-2% water
as defined by residue test at 130°C Adjust by overnight equilibration if needed
6 5 Calibration mixtures
65 1 Reference oil Pipet 150 ml n-hexadecane, 15 0 ml isooctane, and 100 ml
chlorobenzene into a 50 ml glass stoppered bottle Maintain the integrity of the
mixture by keeping stoppered except when withdrawing ahquots
652 Stock standard Pipet 1 0 ml reference oil (6 5 1) into a tared 200 ml volumetric
flask and immediately stopper Weigh and dilute to volume with fluorocarbon-113
653 Working standards Pipet appropriate volumes of stock standard (6 5 2) into 100
ml volumetric flasks according to the cell pathlength to be used Dilute to volume
with fluorocarbon-113 Calculate concentration of standards from the stock
standard
Procedure
7 1 Mark the sample bottle at the water meniscus for later determination of sample volume
If the sample was not acidified at time of collection, add 5 ml hydrochloric acid (6 1) to
the sample bottle After mixing the sample, check the pH by touching pH-sensitive paper
to the cap to insure that the pH is 2 or lower Add more acid if necessary
7 2 Pour the sample into a separatory funnel
7 3 Add 30 ml fluorocarbon-113 (6 2) to the sample bottle and rotate the bottle to rinse the
sides Transfer the solvent into the separatory funnel Extract by shaking vigorously for 2
minutes Allow the layers to separate
7 4 Filter the solvent layer through a funnel containing solvent-moistened filter paper into a
100 ml volumetric flask
NOTE 1 An emulsion that fails to dissipate can be broken by pouring about 1 g sodium
sulfate (6 3) into the filter paper cone and slowly draining the emulsion through the salt
Additional 1 g portions can be added to the cone as required
7.5 Repeat (7 3 and 7 4) twice more with 30 ml portions of fresh solvent, combining all
solvent into the volumetric flask
7 6 Rinse the tip of the separatory funnel, filter paper, and the funnel with a total of 5-10 ml
solvent and collect the rinsings in the flask Dilute the extract to 100 ml If the extract is
known to contain greater than 100 mg of non-hydrocarbon organic material, pipet an
appropriate portion of the sample to a 100 ml volumetric and dilute to volume
7 7 Discard about 5-10 ml solution from the volumetric flask Add 3 g silica gel (6 4) and a
stirring bar, stopper the volumetric flask, and stir the solution for a minimum of 5 mm on
a magnetic stirrer
418 1-2
-------
7 8 Select appropriate working standards and cell pathlength according to the following
table of approximate working ranges
Pathle"gth Range
° mg
Calibrate the instrument for the appropriate cells using a series of working standards
(6 5 3) It is not necessary to add silica gel to the standards Determine absorbance
directly for each solution at the absorbance maximum at about 2930 cm"1 Prepare a
calibration plot of absorbance vs mg petroleum hydrocarbons per 100 ml solution
7 9 After the silica gel has settled in the sample extract, fill a clean cell with solution and
determine the absorbance of the extract If the absorbance exceeds 0 8 prepare an
appropriate dilution
NOTE 2: The possibility that the absorptive capacity of the silica gel has been exceeded
can be tested at this point by adding another 3 0 g silica gel to the extract and repeating
the treatment and determination
7 10 Determine the concentration of petroleum hydrocarbons in the extract by comparing the
response against the calibration plot
Calculations
8 1 Calculate the petroleum hydrocarbons in the sample using the formula
mg/1 Petroleum Hydrocarbons = R * P
where
R = mg of Petroleum Hydrocarbons as determined from the calibration plot (7 10)
D = extract dilution factor, if used
V = volume of sample, in liters
Precision and Accuracy
9 1 Precision and accuracy data are not available at this ti
me
418 1-3
-------
PHENOLICS, TOTAL RECOVERABLE
Method 420.1 (Spectrophotometric, Manual 4-AAP with Distillation)
STORET NO. 32730
Scope and Application
1 1 This method is applicable to the analysis of drinking, surface and saline waters, domestic
and industrial wastes
1 2 The method is capable of measuring phenolic materials at the 5 ug/1 level when the
colored end product is extracted and concentrated in a solvent phase using phenol as a
standard
1 3 The method is capable of measuring phenolic materials that contain more than 50 ug/1
in the aqueous phase (without solvent extraction) using phenol as a standard
14 It is not possible to use this method to differentiate between different kinds of phenols
Summary of Method
2 1 Phenolic materials react with 4-aminoantipynne in the presence of potassium
ferncyanide at a pH of 10 to form a stable reddish-brown colored antipynne dye The
amount of color produced is a function of the concentration of phenolic material
Comments
3 1 For most samples a preliminary distillation is required to remove interfering materials
3 2 Color response of phenolic materials with 4-ammo antipynne is not the same for all
compounds Because phenolic type wastes usually contain a variety of phenols, it is not
possible to duplicate a mixture of phenols to be used as a standard For this reason phenol
has been selected as a standard and any color produced by the reaction of other phenolic
compounds is reported as phenol This value will represent the minimum concentration
of phenolic compounds present in the sample
Sample Handling and Preservation
4 1 Biological degradation is inhibited by the addition of 1 g/1 of copper sulfate to the
sample and acidification to a pH of less than 4 with phosphoric acid The sample should
be kept at 4°C and analyzed within 24 hours after collection
Interference
5 1 Interferences from sulfur compounds are eliminated by acidifying the sample to a pH of
less than 4 with H3PO4 and aerating briefly by stirring and adding CuSO4
5 2 Oxidizing agents such as chlorine, detected by the liberation of iodine upon acidification
in the presence of potassium iodide, are removed immediately after sampling by the
addition of an excess of ferrous ammonium sulfate (7 10) If chlorine is not removed,
the phenolic compounds may be partially oxidized and the results may be low
Approved for NPDES
Issued 1971
Editorial revision 1978
420 1-1
-------
6. Apparatus
6 1 Distillation apparatus, all glass consisting of a 1 liter pyrex distilling apparatus with
Graham condenser
6 2 pH meter
6 3 Spectrophotometer, for use at 460 or 510 nm
6 4 Funnels
6 5 Filter paper
6 6 Membrane filters
6 7 Separatory funnels, 500 or 1,000 ml
6 8 Nessler tubes, short or long form
7 Reagents
7 1 Phosphoric acid solution, 1 + 9 Dilute 10 ml of 85% H3PO4 to 100 ml with distilled
water
7 2 Copper sulfate solution Dissolve 100 g CuSO4»5H2O in distilled water and dilute to 1
liter
7.3 Buffer solution Dissolve 16 9 g NH4C1 in 143 ml cone NH4OH and dilute to 250 ml
with distilled water Two ml should adjust 100 ml of distillate to pH 10
7 4 Ammoantipynne solution Dissolve 2 g of 4AAP in distilled water and dilute to 100 ml
7 5 Potassium ferncyanide solution Dissolve 8 g of K3Fe(CN)6 m distilled water and dilute
to 100 ml
7.6 Stock phenol solution Dissolve 1 0 g phenol in freshly boiled and cooled distilled water
and dilute to 1 liter 1 ml = 1 mg phenol
7 7 Working solution A Dilute 10 ml stock phenol solution to 1 liter with distilled water
1 ml = 10 ug phenol
7 8 Working solution B Dilute 100 ml of working solution A to 1000 ml with distilled water
1 ml = 1 ug phenol
7 9 Chloroform
7.10 Ferrous ammonium sulfate Dissolve 1 1 g ferrous ammonium sulfate in 500 ml distilled
water containing 1 ml cone HaSO4 and dilute to 1 liter with freshly boiled and cooled
distilled water
8 Procedure
8 1 Distillation
811 Measure 500 ml sample into a beaker Lower the pH to approximately 4 with 1+9
H3PO4 (7 1), add 5 ml CuSO4 solution (7 2) and transfer to the distillation
apparatus Omit adding H2PO4 and CuSO4 if sample was preserved as described in
41
812 Distill 450 ml of sample, stop the distillation, and when boiling ceases add 50 ml of
warm distilled water to the flask and resume distillation until 500 ml have been
collected
813 If the distillate is turbid, filter through a prewashed membrane filter
8 2 Direct photometric method
821 Using working solution A (7 7), prepare the following standards in 100 ml
volumetric flasks
420 1-2
-------
ml of working solution A Cone ug/1
ET o~0
05 500
10 1000
20 2000
50 5000
80 8000
10 0 1000 0
8 2 2 To 100 ml of distillate or an aliquot diluted to 100 ml and/or standards, add 2 ml of
buffer solution (7 3) and mix The pH of the sample and standards should be
10 ±02
823 Add 2 0 ml ammoantipyrme solution (7 4) and mix
824 Add 2 0 ml potassium ferncyanide solution (7 5) and mix
825 After 15 minutes read absorbance at 510 nm
8 3 Chloroform extraction method
8 3 1 Using working solution B (7 8), prepare the following standards Standards may be
prepared by pipetting the required volumes into the separatory funnels and
diluting to 500 ml with distilled water
ml of working solution B Cone ug/1
00 00
30 60
50 100
10 0 20 0
20 0 40 0
25 0 50 0
832 Place 500 ml of distillate or an aliquot diluted to 500 ml in a separatory funnel The
sample should not contain more than 25 ug phenol
8 3 3 To sample and standards add 10 ml of buffer solution (7 3) and mix The pH
should be 10 ±02
834 Add 3 0 ml ammoantipyrme solution (7 4) and mix
835 Add 3 0 ml potassium ferncyanide solution (7 5) and mix
836 After three minutes, extract with 25 ml of chloroform (7 9) Shake the separatory
funnel at least 10 times, let CHC13 settle, shake again 10 times and let chloroform
settle again Vent chloroform fumes into hood
837 Filter chloroform extracts through filter paper Do not add more chloroform
Carryout filtration in a hood Dispose of chloroform in environmentally
acceptable manner
838 Read the absorbance of the samples and standards against the blank at 460 nm
Calculation
9 1 Prepare a standard curve by plotting the absorbance value of standards versus the
corresponding phenol concentrations
9 2 Obtain concentration value of sample directly from standard curve.
420 1-3
-------
10 Precision and Accuracy
10 1 Using the extraction procedure for concentration of color, six laboratories analyzed
samples at concentrations of 9 6, 48 3, and 93 5 ug/1 Standard deviations were
±0 99, ±3 1 and ±4 2 ug/1, respectively
10 2 Using the direct photometric procedure, six laboratories analyzed samples at
concentrations of 4 7, 48 2 and 97 0 mg/1 Standard deviations were ±0 18, ±0 48 and
±1 58 mg/1, respectively
Bibliography
1 Annual Book of ASTM Standards, Part 31, "Water", Standard D1783-70, p553 (1976)
2. Standard Methods for the Examination of Water and Wastewater, 14th Edition, p574-581,
Method 510 through 5 IOC, (1975)
420 1-4
-------
PHENOLICS, TOTAL RECOVERABLE
Method 420.2 (Colorimetric, Automated 4-AAP with Distillation)
STORET NO. 32730
1 Scope and Application
1 1 This method is applicable to the analysis of drinking, surface and saline waters, domestic
and industrial wastes
1 2 The method is capable of measuring phenolic materials from 2 to 500 ug/1 m the
aqueous phase using phenol as a standard The working ranges are 2 to 200 ug/1 and 10
to 500 ug/1
2 Summary of Method
2 1 This automated method is based on the distillation of phenol and subsequent reaction of
the distillate with alkaline ferncyamde and 4-ammoantipynne to form a red complex
which is measured at 505 or 520 nm The same manifold is used with the AAI or AAII
3 Sample Handling and Preservation
3 1 Biological degradation is inhibited by the addition of 1 g/1 of copper sulfate to the
sample and acidification to a pH of less than 4 with phosphoric acid The sample should
be kept at 4°C and analyzed within 24 hours after collection
4 Interference
4 1 Interferences from sulfur compounds are eliminated by acidifying the sample to a pH of
less than 4 0 with H3PO4 and aerating briefly by stirring and adding CuSO4
4 2 Oxidizing agents such as chlorine, detected by the liberation of iodine upon acidification
in the presence of potassium iodide, are removed immediately after sampling by the
addition of an excess of ferrous ammonium sulfate (6 5) If chlorine is not removed, the
phenolic compounds may be partially oxidized and the results may be low
4 3 Background contamination from plastic tubing and sample containers is eliminated by
filling the wash receptacle by siphon (using Kel-F tubing) and using glass tubes for the
samples and standards
5 Apparatus
5 1 Techmcon AutoAnalyzer (I or II)
511 Sampler equipped with continuous mixer
5 1 2 Manifold
513 Proportioning pump II or III
514 Heating bath with distillation coil
5 1 5 Distillation head
5 1 6 Colorimeter equipped with a 50 mm flow cell and 505 or 520 nm filter
5 1 7 Recorder
6 Reagents
6 1 Distillation reagent Add 100 mi of cone phosphoric acid (85% H3PO4) to 800 ml of
distilled water, cool and dilute to 1 liter
Issued 1974
420 2-1
-------
6 2 Buffered potassium ferncyamde Dissolve 2 0 g potassium ferncyamde, 3 1 g bone acid
and 3 75 g potassium chloride m 800 ml of distilled water Adjust to pH of 10 3 with 1 N
sodium hydroxide (6 3) and dilute to 1 liter Add 0 5 ml of Bnj-35 Prepare fresh weekly
6 3 Sodium hydroxide (IN) Dissolve 40 g NaOH in 500 ml of distilled water, cool and dilute
to 1 liter
6 4 4-Ammoantipynne Dissolve 0 65 g of 4-aminoantipyrme in 800 ml of distilled water and
dilute to 1 liter Prepare fresh each day
6 5 Ferrous ammonium sulfate Dissolve 1 1 g ferrous ammonium sulfate in 500 ml distilled
water containing 1 ml H2SO4 and dilute to 1 liter with freshly boiled and cooled distilled
water
6 6 Stock phenol Dissolve 1 00 g phenol m 500 ml of distilled water and dilute to 1000 ml
Add 1 g CuSO4 and 0 5 ml cone H3PO4 as preservative 1 0 ml = 10 mg phenol
6 7 Standard phenol solution A Dilute 10 0 ml of stock phenol solution (6 6) to 1000 ml
10 ml = 0 01 mg phenol
6 8 Standard phenol solution B Dilute 100 0 ml of standard phenol solution A (6 7) to 1000
ml with distilled water 1 0 ml = 0 001 mg phenol
6 9 Standard solution C Dilute 100 0 ml of standard phenol solution B (6 8) to 1000 ml with
distilled water 1 0 ml = 0 0001 mg phenol
610 Using standard solution A, B or C prepare the following standards in 100 ml volumetric
flasks Each standard should be preserved by adding 0 1 g CuSO4 and 2 drops of cone
H3PO4tolOOOml
ml of Standard Solution Cone ug/1
Solution C
10 10
20 20
30 30
50 50
Solution B
10 100
20 200
50 500
100 1000
Solution A
2 200
3 300
5 500
Procedure
7 1 Set up the manifold as shown in Figures 1 or 2
7 2 Fill the wash receptacle by siphon Use Kel-F tubing with a fast flow (1 liter/hr)
7 3 Allow colorimeter and recorder to warm up for 30 minutes Run a baseline with all
reagents, feeding distilled water through the sample line Use polyethylene tubing for
420 2-2
-------
sample line When new tubing is used, about 2 hours may be required to obtain a stable
baseline This two. hour time period may be necessary to remove the residual phenol from
the tubing
7 4 Place appropriate phenol standards in sampler in order of decreasing concentration
Complete loading pf sampler tray with unknown samples, using glass tubes
NOTE 1: If samples have not been preserved as instructed m (3 1), add 0 1 g CuSO4 and
2 drops of cone H3PO4 to 100 ml of sample
7 5 Switch sample line from distilled water to sampler and begin analyses
8 Calculation
8 1 Prepare standard curve by plotting peak heights of standards against concentration
values Compute concentration of samples by comparing sample peak heights with
standards
9 Precision and Accuracy
91 In a single laboratory (EMSL), using sewage samples at concentrations of 3 8, 15,43 and
89 ug/1, the standard deviations were ±0,5, ±0 6, ±0 6 and ±1,0 ug/1, respectively At
concentrations of 73, 146, 299 and 447 ug/1, the standard deviations were ±10,
±18, ±42 and ±5 3 ug/1, respectively
92 In a single laboratory (EMSL), using sewage samples at concentrations of 5 3 and 82
ug/1, the recoveries were 78% and 98% At concentrations of 168 and 489 ug/1, the
recoveries were 97% and 98%, respectively
Bibliography
1 Techmcon Auto Analyzer II Methodology, Industrial Method No 127-71W, A All
2 Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 574,
Method 510 (1975)
3 Gales, M E and Booth, R,L , "Automated 4 AAP Phenolic Method", AWWA 68, 540 (1976)
420 2-3
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-------
PHENOLICS, TOTAL RECOVERABLE
Method 420.3 (Spectrophotometric, MBTH with Distillation)
STORET NO. 32730
1 Scope and Application
1 1 This method is applicable to the analysis of drinking, surface and saline waters, domestic
and industrial wastes
1 2 The method is capable of measuring phenolic materials at the 2 ug/1 level when the
colored end product is extracted and concentrated in a solvent phase using phenol as a
standard
1 3 The method is capable of measuring phenolic materials that contain from 50 to 1000
ug/1 in the aqueous phase (without solvent extraction) using phenol as a standard
14 It is not possible to use this method to differentiate between different kinds of phenols
2 Summary of Method
2 1 This method is based on the coupling of phenol with MBTH in an acid medium using
cenc ammonium sulfate as an oxidant The coupling takes place in the p-position, if this
position is occupied, the MBTH reagent will react at a free o-position The colors
obtained have maximum absorbance from 460-595 nm For phenol and most phenolic
mixtures the absorbance is 520 and 490 nm
3 Comments
3 1 For most samples a preliminary distillation is required to remove interfering materials
3 2 Color response of phenolic materials with MBTH is not the same for all compounds
Because phenolic type wastes usually contain a variety of phenols, it is not possible to
duplicate a mixture of phenols to be used as a standard For this reason phenol has been
selected as a standard and any color produced by the reaction of other phenolic
compounds is reported as phenol This value will represent the minimum concentration
of phenolic compounds present in the sample
4 Sample Handling and Preservation
4 1 Biological degradation is inhibited by the addition of 1 g/1 of copper sulfate to the
sample and acidification to a pH of less than 4 with sulfunc acid The sample should be
kept at 4°C and analyzed within 24 hours after collection
5 Interference
5 1 Interferences from sulfur compounds are eliminated by acidifying the sample to a pH of
less than 4 0 with H2SO4 and aerating briefly by stirring and adding CuSO4
5 2 Oxidizing agents such as chlorine, detected by the liberation of iodine upon acidification
in the presence of potassium iodide, are removed immediately after sampling by the
addition of an excess of ferrous ammonium sulfate (6 5) If chlorine is not removed, the
phenolic compounds may be partially oxidized and the results may be low
5 3 Phosphate causes a precipitate to form, therefore, phosphoric acid should not be used for
preservation All glassware should be phosphate free
Issued 1978
420 3-1
-------
5 4 High concentrations of aldehydes may be an interference
6, Apparatus
6 1 Distillation apparatus All glass consisting of a 1 liter pyrex distilling apparatus with
Graham condenser
6 2 pH meter
6 3 Spectrophotometer
6 4 Funnels
6 5 Filter paper
6 6 Membrane filters
6 7 Separatory funnels
7. Reagents
7 1 Copper sulfate solution Dissolve 100 g CuSO4«5 H2O in distilled water and dilute to 1
liter
7 2 Sulfunc acid, 1 N Add 28 ml of cone H2SO4 to 900 ml of distilled water, mix and dilute
to 1 liter
7 3 MBTH solution, 0 05% Dissolve 0 1 g of 3-methyl-2-benzothiazolmone hydrazone
hydrochlonde in 200 ml of distilled water
7 4 Cenc ammonium sulfate solution Add 2 0 g of Ce(SO4)2«2(NH4)2SO4»2H2O and 2 0 ml
of cone H2SO4 to 150 ml of distilled water After the solid has dissolved dilute to 200 ml
with distilled water
7 5 Buffer solution Dissolve in the following order, 8 g of sodium hydroxide, 2 g EDTA
(disodmm salt) and 8 g boric acid in 200 ml of distilled water Dilute to 250 ml with
distilled water
7.6 Working buffer solution Make a working solution by mixing an appropriate volume of
buffer solution (7 5) with an equal volume of ethanol
7 7 Chloroform
7 8 Stock phenol Dissolve 1 00 g phenol in 500 ml of distilled water and dilute to 1000 ml
Add 1 g CuSO4 and 0 5 ml cone H2SO4 as preservative 1 0 ml = 1 0 mg phenol
7.9 Standard phenol solution A Dilute 10 0 ml of stock phenol solution (7 8) to 1000 ml 1 0
ml = 0 01 mg phenol
7.10 Standard phenol solution B Dilute 100 0 ml of standard phenol solution A (7 9) to 1000
ml with distilled water 1 0 ml = 0 001 mg phenol
8 Procedure
8 1 Distillation
8 1 1 To 500 ml of sample add 5 ml of copper sulfate solution (7 1) and adjust the pH to
approximately 4 with 1 N sulfunc acid solution (7 2)
8.1 2 Distill over 450 ml of sample, add 50 ml of warm distilled water to flask, and
resume distillation until 500 ml has been collected
813 If the distillate is turbid, filter through a prewashed membrane filter
8 2 Concentration above 50 ug/1
821 To 100 ml of distillate or an aliquot diluted to 100 ml, add 4 ml of MBTH solution
(73)
822 After 5 minutes, add 2 5 ml of cenc amihomum sulfate solution (7 4)
420 3-2
-------
823 Wait another 5 minutes and add 7 ml of working buffer solution (7 6)
824 After 15 minutes, read the absorbance at 520 nm against a reagent blank The color
is stable for 4 hours
8 3 Concentration below 50 ug/1
8 3 1 To 500 ml of distillate in a separately funnel, add 4 ml of MBTH solution (7 3)
832 After 5 minutes, add 2 5 ml of eerie ammonia sulfate solution (7 4)
833 After an additional 5 minutes, add 7 ml of working buffer solution (7 6)
834 After 15 minutes, add 25 ml of chloroform Shake the separatory funnel at least 20
times Allow the layer to separate, and pass the chloroform layer through filter
paper
835 Read the absorbance at 490 nm against a reagent blank
9 Calculation
9 1 Prepare a standard curve by plotting absorbance against concentration values
9 2 Obtain concentration value of sample directly from prepared standard curve
10 Precision and Accuracy
101 Precision and accuracy data are not available at this time
Bibliography
1 Fnestad, H O , Ott, E E, and Gunther, F A , "Automated Colonmetnc Micro Determination
of Phenol by Oxidative Coupling with 3-Methyl-2-benzothiazolmone Hydrazone", Techmcon
International Congress (1969)
2 Gales, M E, "An Evaluation of the 3-Methyl-2 benzothiazohnone Hydrazone Method for the
Determination of Phenols in Water and Wastewater", Analyst, 100, No 1197, 841 (1975)
420 3-3
-------
METHYLENE BLUE ACTIVE SUBSTANCES (MBAS)
Method 425.1 (Colorimetric)
STORET NO. 38260
Scope and Application
1 1 This method is applicable to the measurement of methylene blue active substances
(MBAS) in drinking waters, surface waters, domestic and industrial wastes It is not
applicable to measurement of surfactant-type materials in salme waters
12 It is not possible to differentiate between linear alkyl sulfonate (LAS) and alkyl benzene
sulfonate (ABS) or other isomers of these types of compounds However, LAS has
essentially replaced ABS on the surfactant market so that measurable surfactant
materials will probably be LAS type materials
1 3 The method is applicable over the range of 0 025 to 100 mg/1 LAS
Summary of Method
2 1 The dye, methylene blue, m aqueous solution reacts with amomc-type surface active
materials to form a blue colored salt The salt is extractable with chloroform and the
intensity of color produced is proportional to the concentration of MBAS
Comments
3 1 Materials other than man-made surface active agents which react with methylene blue
are organically bound sulfates, sulfonates, carboxylates, phosphates, phenols, cyanates,
thiocyanates and some inorganic ions such as nitrates and chlorides However, the
occurrence of these materials at interference levels is relatively rare and with the
exception of chlorides may generally be disregarded
3 2 Chlorides at concentration of about 1000 mg/1 show a positive interference but the
degree of interference has not been quantified For this reason the method is not
applicable to brine samples
3 3 Naturally occurring organic matenals that react with methylene blue are relatively
insignificant Except under highly unusual circumstances, measurements of MBAS in
finished waters, surface waters and domestic sewages may be assumed to be accurate
measurements of man-made surface active agents
Precision and Accuracy
41 On a sample of filtered river water, spiked with 2 94 mg LAS/liter, 110 analysts obtained
a mean of 2 98 mg/1 with a standard deviation of ±0 272
4 2 On a sample of tap water spiked with 0 48 mg LAS/liter, 110 analysts obtained a mean of
0 49 mg/1 with a standard deviation of ±0 048
43 On a sample of distilled water spiked with 0 27 mg LAS/liter, 110 analysts obtained a
mean of 0 24 mg/1 with a standard deviation of ±0 036
4 4 Analytical Reference Service, Water Surfactant No 3, Study No 32, (1968)
Approved for NPDES
Issued 1971
425 1-1
-------
5 References
5.1 The procedure to be used for this determination is found m
Standard Methods for the Examination of Water and Wastewaters, 14th Edition, p 600,
Method No 512A(1975)
Annual Book of ASTM Standards, Part 31, "Water", Standard D 2330-68, Method A, p
494(1976)
425 1-2
-------
NTA
Method 430.1 (Colorimetric, Manual, Zinc-Zincon)
STORET NO. 00695
Scope and Application
11 In this method NTA refers to the tn-sodmm salt of nitnlotnacetic acid,
N(CH2COONa)3
1 2 This method is applicable to surface waters in the range of 0 5-10 0 mg/1 NTA
Summary of Method"'
2 1 Zinc forms a blue-colored complex with 2 carboxy-2'-hydroxy-5'-sulfoformazylbenzene
(Zmcon) in a solution buffered to pH 9 2 When NTA is added, the Zmc-Zmcon complex
is broken which reduces the absorbance in pioportion to the amount of NTA present
Sample Handling and Preservation
3 1 Samples should be analyzed as soon as possible, as NTA has been shown to be
biodegradable™
Interferences
4 1 Cations, such as calcium, magnesium, zinc, copper, iron, and manganese, complex with
NTA and give a negative interference These ions are removed by batch treating samples
with ion-exchange resin At concentrations higher than expected in typical river waters'3',
only zinc, copper, and iron were not completely removed with ion-exchange treatment
Results are summarized in Table 1
Table 1
Interference of Common Metals
Metal
Blank
Zinc
Boron
Iron
Molybdenum
Manganese
Aluminum
Copper
Strontium
mg/1
added
00
20
50
50
20
40
30
05
50
1 0 mg/1 5
NTA
Recoveries
1 1
<05
1 1
095
10
1 1
085
<05
10
0 mg/1
NTA
55
06
55
46
55
56
52
34
54
4 2 This method has not been found applicable to salt waters
Issued 1971
430 1-1
-------
5. Apparatus
5 1 Shaking machine, tray type, for stirring sample-resin mixtures in 125 ml Erlenmeyer
flasks
5 2 Photometer, suitable for measurements at 620 nm
6 Reagents
6 1 Sodium hydroxide, 6N Dissolve 120 g NaOH m distilled water and dilute to 500 ml
6.2 Buffer Dissolve 31 g boric acid and 37 g potassium chloride in 800 ml distilled water
Adjust pH to 9 2 with 6N NaOH (6 1) Dilute to 1 liter
6 3 Hydrochloric acid, 2N Dilute 83 ml cone HC1 to 500 ml with distilled water
6 4 Zinc Dissolve 0 44 g ZnSO4«7H2O in 100 ml 2N HC1 (6 3) and dilute to 1 liter with
distilled water
6 5 Sodium hydroxide, IN Dissolve 4 g NaOH in distilled water and dilute to 100 ml
6 6 Zmc-Zmcon Dissolve 0 13 g Zincon (2-carboxy-2'-hydroxy-5'-sulfoformazyl benzene)
m 2 ml IN NaOH (6 5) Add 300 ml buffer (6 2) While stirring, add 15 ml Zinc solution
(6 4) and dilute to 1 liter with distilled water
6 7 Ion-exchange resm Dowex 50W-X8,50-100 mesh, Na"1" form (or equivalent)
6 8 Stock NTA solution Dissolve 1 0700 g N(CH2COONa)3-H2O in distilled water and
dilute to 1000 ml 1 0 ml = 1 0 mg NTA
7. Procedure
7.1 Filter approximately 50 ml of well-mixed sample through a 0 45 u membrane filter
7 2 Prepare a series of standards from 0 5 to 10 mg/1 NTA, including a blank of distilled
water Treat standards and blank in same manner as filtered samples
7 3 To a 25 ml sample ma 125 ml Erlenmeyer flask add approximately 2 5 g ion-exchange
resin (6 7) Agitate sample for at least 15 minutes
7 4 Filter through coarse filter paper to remove resin Pipette 15 0 ml of filtrate into a 50 ml
beaker Add 25 0 ml Zmc-Zmcon (6 6) by pipette
7 5 Read absorbance against distilled water at 620 nm in a 1 cm or 2 cm cell
8, Calculation
8.1 Prepare standard curve by plotting absorbance of standards vs NTA concentrations
Calculate concentrations of NTA, mg/1, directly from this curve
9 Precision and Accuracy
91 In a single laboratory (MDQARL), using spiked surface water samples at concentrations
of 0 5,2,6, and 10 mg/1 NTA, standard deviations were ±0 17, ±0 14, ±0 1, and ±0 16,
respectively
92 In a single laboratory (MDQARL), using spiked surface water samples at concentrations
of 1 0 and 7 5 mg/1 NTA, recoveries were 120% and 103%, respectively
Bibliography
1 Thompson, J E, and Duthie, J R, "The Biodegradabihty and Treatment of NTA", Jour
WPCF, 40, No 2,306 (1968).
2 Shumate, K S et al, "NTA Removal by Activated Sludge - Field Study", ibid , 42, No 4, 631
(1970)
430 1-2
-------
Kopp, J F, and Kroner, R C, "Trace Metals m Waters of the United States", USDI,
FWPCA, DPS, 1014 Broadway, Cincinnati, Ohio 45202
430 1-3
-------
NTA
Method 430.2 (Colorimetric, Automated, Zinc-Zincon) ,
i
1 STORET NO. 00695
i
Scope and Application
11 In this method, NTA refers to the tn-sodium salt of mtnlotnacetic acid,
N(CH2COONa)3
1 2 This method is applicable to surface waters in the range of 0 04 to 1 0 mg/1 and 0 5 to
100 mg/1 NTA, depending on which manifold system is used It does not apply to saline
waters, a positive interference of 0 5 to 1 0 mg/1 is present in sewage-type samples.
1 3 Approximately 13 samples per hour can be analyzed
Summary of Method(1)
2 1 Zinc forms a blue-colored complex with 2-carboxy-2'-hydroxy-5'-sulfoformazylbenzene
(Zincon) in a solution buffered to pH 9 2 When NTA is addd, the Zinc-Zincon complex
is broken which reduces the absorbance m proportion to the amount of the NTA present
Sample Handling and Preservation
3 1 Samples should be analyzed as soon as possible, as NTA has been shown to be
biodegradable<2)
Interferences
4 1 Cations, such as calcium, magnesium, zinc, copper, iron, and manganese, complex with
NTA and give a negative interference These ions are removed automatically by passing
the sample through an ion-exchange column At concentrations higher than expected in
typical river waters,(3> only iron was not completely removed by this column treatment
Results, summarized in Tables 1 and 2, show that iron gives a negative interference in
concentrations above 3 0 mg/1 NTA
i
t
TABLE 1 |
Interference of Common Metals
i Recoveries
mg/1 | 10 mg/1 5 0 mg/1
Metal added NTA NTA
Blank 00 1050
Zinc 20 09 49
Iron 50 > 08 38
Manganese 40 1049
Copper 05 > 12 49
Issued 1971
430 2-1
-------
TABLE 2
Effect of Iron on NTA Recovery in River Water
Iron Added NTA Recovered, mg/1
mg/1 (0 5 mg/1 added)
00 052
05 052
10 052
20 052
30 048
40 045
50 039
42 At concentration levels below 0 05 mg/1 NTA, negative peaking may occur during
analyses
Apparatus
5.1 Techmcon AutoAnalyzer consisting of
5 1 1 Sampler I or II
5 1 2 Manifold
513 Proportioning pump
5 1 4 Colorimeter equipped with 15 mm tubular flow cell and 600 or 625 nm filter
515 Recorder
Reagents
6.1 Sodium hydroxide, 6N Dissolve 120 g NaOH in distilled water and dilute to 500 ml
6 2 Buffer Dissolve 31 g boric acid and 37 g potassium chloride in 800 ml distilled water
Adjust pH of solution to 9 2 with 6N NaOH (6 1) Dilute to 1 liter
6 3 Hydrochloric acid, 2N Dilute 83 ml cone HC1 to 500 ml with distilled water
6 4 Zinc Dissolve 0 44 g ZnSO4»7H2O in 100 ml 2N HC1 (6 3) Dilute to 1 liter with distilled
water
6 5 Sodium hydroxide, IN Dissolve 4 g NaOH in distilled water and dilute to 100 ml
6 6 Zmc-Zmcon reagent A (0 04-1 0 mg/1 NTA) Dissolve 0 065 g Zmcon powder (2-
carboxy-2'-hydroxy-5'-sulfoformazyl benzene) in 2 ml of 1 N NaOH (6 5) Add 300 ml
buffer (6 2) Stir on a magnetic stirrer and add 7 5 ml zinc solution (6 4) Dilute to 1 liter
with distilled water This solution is stable for 12 hours
6 7 Zmc-Zmcon reagent B (0 5-10 mg/1 NTA) Dissolve 0 13 g Zmcon in 2 ml 1 N NaOH
(6 5), Stir on magnetic stirrer and add 300 ml buffer (6 2) and 15 ml zinc solution (6 4)
Dilute to 1 liter with distilled water Stable for 1 week
68 Ion-exchange resin, H+ form 20-50 mesh or 30-80 mesh, Dowex 50W-XB or
equivalent
NOTE: Column is prepared by sucking a water slurry of the resin into 12 inches of3/16-
mch OD sleeving This may be conveniently done by using a pipette and a loose-fitting
glass wool plug in the sleeve
6,9 Stock NTA solution Dissolve 1 0700 g of N(CH2COONa)3«H2O in 500 ml of distilled
water and dilute to 1000 ml 1 0 ml = 1 0 mg NTA
430 2-2
-------
6 10 Working solution A Dilute 10 0 ml of slock NTA solution to 100 0 ml with distilled
water 1 0 ml = 0 1 mg NTA Prepare daily
6 11 Working solution B Dilute 10 0 ml of Solution A to 100 0 ml with distilled water 1 0 ml
= 0 01 mg NTA Prepare daily
6 12 Working solution C Dilute 10 0 ml of Solution B to 100 0 ml with distilled water 1 0 ml
= 0 001 mg NTA Prepare daily
613 Prepare a series of standards by diluting suitable volumes of working solutions to 100 0
ml with distilled water .The following dilutions are suggested
ml of Solution C/100 ml Cong, mg NTA/1
2 002
4 004
6 006
8 008
10 010
ml of Solution B/100 ml
2 020
4 040
6 060
8 080
10 100
ml of Solution A/100 ml
2 20
4 40
6 60
8 80
10 , 100
7 Procedure
7 1 Set up manifold as shown in Figure 1
7 2 Allow both colorimeter and recorder to warm up for 30 minutes Run a baseline with all
reagents, feeding distilled water through the sample line Adjust dark current and
operative opening on colorimeter to obtain suitable baseline
7 3 Place wash water tubes in sampler in sets of two, leaving every third position vacant Set
sampling time at 1 5 minutes
7 4 Place NTA standards in sampler Complete filling of sample tray with unknown samples
7 5' Switch sample line from distilled water to sampler and begin analysis
8 Calculation
8 1 Prepare standard curve by plotting peak heights of processed NTA standards against
known concentrations Compute concentration of samples by comparing sample peak
heights with standard curve
430 2-3
-------
9 Precision and Accuracy
9.1 In a single laboratory (EMSL), using surface water samples at concentrations of 0 1,
0 18, 027, and 044 mg/1, the standard deviations were ±001, ±0004, ±0004, and
±0 005, respectively At concentrations of 1 3, 4 0, 5 8, and 7 4 mg/1, the standard
deviations were ±005, ±005, ±007, and ±0 1, respectively
92 In a single laboratory (EMSL), using surface water samples at concentrations of 0 18 and
0 27 mg/1, recoveries were 101% and 106%, respectively At concentrations of 4 0 and
5 8 mg/1, the recoveries were 98% and 96%, respectively
Bibliography
1 Thompson, J E, and Duthie, J R, "The Biodegradabihty and Treatment of NTA", Jour
WPCF, 40, No 2, 306 (1968)
2 Shumate, K S et al, "NTA Removal by Activated Sludge - Field Study", ibid , 42, No 4, 631
(1970) ~
3. Kopp, J F and Kroner, R C, "Trace Metals in Waters of the United States", USDI,
FWPCA, DPS, 1014 Broadway, Cincinnati, Ohio 45202
430 2-4
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6US GOVERNMENT PRINTING OFFICE 1991-s^e l87/^o533
430 2-5
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