EPA Document #: EPA/600/R-05/055
METHOD 415.3 DETERMINATION OF TOTAL ORGANIC CARBON AND
SPECIFIC UV ABSORBANCE AT 254 nm IN SOURCE WATER
AND DRINKING WATER
Revision 1.1
February, 2005
B. B. Potter, USEPA, Office of Research and Development, National Exposure Research Laboratory
J. C. Wimsatt, The National Council On The Aging, Senior Environmental Employment Program
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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METHOD 415.3
DETERMINATION OF TOTAL ORGANIC CARBON AND SPECIFIC UV ABSORBANCE
AT 254 nm IN SOURCE WATER AND DRINKING WATER
1.0 SCOPE AND APPLICATION
1.1 This method provides procedures for the determination of total organic carbon (TOC),
dissolved organic carbon (DOC), and UV absorption at 254 nm (UVA) in source
waters and drinking waters. The DOC and UVA determinations are used in the
calculation of the Specific UV Absorbance (SUVA). For TOC and DOC analysis, the
sample is acidified and the inorganic carbon (1C) is removed prior to analysis for
organic carbon (OC) content using a TOC instrument system. The measurements of
TOC and DOC are based on calibration with potassium hydrogen phthalate (KHP)
standards. This method is not intended for use in the analysis of treated or untreated
industrial wastewater discharges as those wastewater samples may damage or
contaminate the instrument system(s).
1.2 The three (3) day, pooled organic carbon detection limit (OCDL) is based on the
detection limit (DL) calculation.1 It is a statistical determination of precision, and
may be below the level of quantitation. The determination of OCDL is dependent on
the analytical instrument system's precision, the purity of laboratory reagent water
(LRW), and the skill of the analyst. Different TOC instrument systems have
produced significantly different OCDLs that range between 0.02 and 0.12 mg/L OC
for both TOC and DOC measurements. Examples of these data can be seen in
Section 17, Table 17.1. It should be noted that background levels of OC
contamination are problematic. The minimum reporting level (MRL) for TOC and
DOC will depend on the laboratory's ability to control background levels (Sect. 4).
2.0 SUMMARY OF METHOD
2.1 In both TOC and DOC determinations, organic carbon in the water sample is oxidized
to produce carbon dioxide (CO2), which is then measured by a detection system.
There are two different approaches for the oxidation of organic carbon in water
samples to carbon dioxide gas: (a) combustion in an oxidizing gas and (b) UV
promoted or heat catalyzed chemical oxidation with a persulfate solution. Carbon
dioxide, which is released from the oxidized sample, is detected by a conductivity
detector or by a nondispersive infrared (NDIR) detector. Instruments using any
combination of the above technologies maybe used in this method.
2.2 Settleable solids and floating matter may cause plugging of valves, tubing, and the
injection needle and/or injection port. The TOC procedure allows the removal of
settleable solids and floating matter. The suspended matter is considered part of the
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sample. The resulting water sample is then considered a close approximation of the
original whole water sample for the purpose of TOC measurement.
2.3 The DOC procedure requires that the sample be passed through a 0.45-|j,m filter prior
to analysis to remove particulate OC from the sample.
2.4 The TOC and DOC procedures require that all 1C be removed from the sample before
the sample is analyzed for organic carbon content. If the 1C is not completely
removed, significant error will occur. The sample, which is then free from 1C
interference, is injected into a TOC instrument system. The organic carbon is
oxidized to CO2 which is released from the sample, detected, and reported as mg/L or
ppm TOC or DOC.
2.5 The UVA procedure requires that the sample be passed through a 0.45-um filter and
transferred to a quartz cell. It is then placed in a spectrophotometer to measure the
UV absorbance at 254 nm and reported in cm"1.
2.6 The SUVA calculation requires both the DOC and UVA measurement. The SUVA is
calculated by dividing the UV absorbance of the sample (in cm"1) by the DOC of the
sample (in mg/L) and then multiplying by 100 cm/M. SUVA is reported in units of
L/mg-M. The formula for the SUVA may be found in Section 12.2.
3.0 DEFINITIONS AND TERMS
NOTE: To assist the reader, a table of acronyms can be found in Section 3.20.
3.1 ANALYSIS BATCH - A set of samples prepared and analyzed on the same
instrument during a 24-hour period. For a TOC/DOC analysis batch, the set may
contain: calibration standards, laboratory reagent blank and/or filter blanks, field
blank, field samples, laboratory fortified matrix sample, field duplicate sample, and
continuing calibration check standards. For a UVA analysis batch, the set may
contain: filter blanks, field samples, field blank, field duplicate sample, and
spectrophotometer check solutions with associated blank. An analysis batch is
limited to 20 field samples. QC samples are not counted towards the 20 sample limit.
QC requirements are summarized in Table 17.6.
3.2 BLANKS - Prepared from a volume of LRW (Sect. 3.9) and used as needed to fulfill
quality assurance requirements and to monitor the analytical system.
3.2.1 CALIBRATION BLANK (CB) - The calibration blank is a volume of LRW
that is treated with the same reagents used in the preparation of the calibration
standards. The CB is a "zero standard" and is used to calibrate the TOC
instrument. The CB is made at the same time as the calibration standards and
stored along with and under the same conditions as the calibration standards.
The CB is also used to monitor increases in organic background found in the
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calibration standards over time by analyzing it as a sample and comparing the
results with initial analysis of the CB.
3.2.2 FIELD REAGENT BLANK (FRB) - A volume, equivalent to that which is
collected at a sample site, of LRW is placed in a sample bottle or vial. A
second empty sample bottle or vial accompanies the LRW sample container to
the sample site. At the sample site, the LRW is transferred into the empty
bottle or vial which then becomes the FRB. The FRB is treated as a sample in
all respects including shipment from the sampling site, exposure to the
sampling site conditions, storage, preservation, and all analytical procedures.
The purpose of the FRB is to determine if the TOC, DOC, and UVA
measurements of the samples collected in the field are free from interferences
or contamination as a result of the sample collection procedure and/or
transport of the sample(s) to the laboratory. The FRB is optional and is
usually used when the laboratory suspects a problem in sample collection and
handling.
3.2.3 FILTER BLANK (FB) - The FB is an aliquot of LRW that is filtered and
analyzed using the same procedures as field samples undergoing DOC and
UVA determinations. For DOC and UVA analyses, the FB serves as the LRB.
The FB will give an indication of overall contribution of organic carbon
contamination from laboratory sources such as the LRW itself, labware
cleaning procedures, reagents, the filter apparatus, filter, and instrument
system(s).
3.2.4 LABORATORY REAGENT BLANK (LRB) - A volume of LRW that is
prepared with each sample set and is treated exactly as a TOC sample
including exposure to all glassware, plasticware, equipment, and reagents that
are used with other samples. The LRB is used to determine if organic
contamination or other interferences are present in the laboratory environment,
reagents, apparatus, or procedures. The LRB must be acidified and sparged
following the same procedure as is used to prepare the TOC sample(s).
3.3 CALIBRATION SOLUTIONS - Calibration should be performed according to the
manufacturer's operation manual. The following solutions are used to calibrate the
TOC instrument system for TOC or DOC determinations (calibration solutions are
not used for UVA determination):
3.3.1 ORGANIC CARBON PRIMARY DILUTION STANDARD (OC-PDS) - A
concentrated solution containing potassium hydrogen phthalate (KHP) in
LRW water that is prepared in the laboratory or is an assayed KHP standard
solution purchased from a commercial source. The OC-PDS is used for the
preparation of organic carbon calibration standards (OC-CAL), continuing
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calibration check standards (CCC), and laboratory fortified matrix samples
(LFM).
3.3.2 ORGANIC CARBON CALIBRATION STANDARD (OC-CAL) - A solution
prepared from the OC-PDS and diluted with LRW to various concentrations.
The OC-CAL solutions are used to calibrate the instrument response with
respect to organic carbon concentration.
3.3.3 CONTINUING CALIBRATION CHECK (CCC) - An OC-CAL solution
which is analyzed periodically to verify the accuracy of the existing calibration
of the instrument (Sect. 10.3).
3.4 DISSOLVED ORGANIC CARBON (DOC) - Organic matter, contained in a water
sample that is soluble and/or colloidal, that can pass through a 0.45-urn filter.
3.5 FIELD DUPLICATES (FD1 and FD2) - Two separate samples collected at the same
time and place under identical circumstances, and treated exactly the same throughout
field and laboratory procedures. Analyses of FD1 and FD2 give a measure of the
precision associated with sample collection, preservation, and storage, as well as
laboratory procedures.
3.6 INORGANIC CARBON (1C) - Carbon in water samples from non organic sources,
composed mainly from dissolved mineral carbonates and carbon dioxide. 1C can
interfere with the determination of TOC and DOC if it is not removed.
3.7 LABORATORY FORTIFIED BLANK (LFB) - An aliquot of LRW or other blank
matrix to which a known quantity of KHP is added in the laboratory. The LFB is
subjected to the same preparation and analysis as a sample. The purpose of the LFB
is to determine whether the methodology is in control, and whether the laboratory is
capable of making accurate and precise measurements. For this method, a TOC LFB
is the same as a CCC (Sect. 10.3) and no additional LFB is required. One LFB is
required with each DOC analysis batch. No LFB is required for UVA analysis.
3.8 LABORATORY FORTIFIED SAMPLE MATRIX (LFM) - An aliquot of a field
sample to which a known quantity of KHP is added in the laboratory. The LFM is
subjected to the same preparation and analysis as a sample, and its purpose is to
determine whether the sample matrix affects the accuracy of the TOC or DOC
analytical results. The background concentration of organic carbon in the sample
matrix must be determined in a separate aliquot and the measured value in the LFM
corrected for background concentration.
3.9 LABORATORY REAGENT WATER (LRW) - The LRW may be distilled and/or
deionized (DI) water, or high pressure liquid chromatography (HPLC) reagent grade
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or equivalent water which is low in TOC concentration, meeting the requirements as
stated in Section 7.2.
3.10 MATERIAL SAFETY DATA SHEET (MSDS) - Written information provided by a
vendor describing a chemical's toxicity, health hazards, physical and chemical
properties (flammability, reactivity, etc.), storage, handling, and spill precautions.
3.11 MINIMUM REPORTING LEVEL (MRL) - The minimum concentration of organic
carbon that can be reported as a quantified value in a sample following analysis. This
concentration is determined by the background level of the analyte in the LRBs and
the sensitivity of the method to organic carbon. See Section 9.10 for guidelines in the
establishment of the MRL.
3.12 ORGANIC CARBON DETECTION LIMIT (OCDL) - The calculated minimum
concentration of a known amount of organic carbon (OC) added to the LRW that can
be identified, measured as either TOC or DOC, and reported with 99% confidence
that the OC concentration is greater than zero as per the procedure in Section 9.2.1.
3.13 ORGANIC CARBON (OC) - In this method, when a concentration or instrument
reading applies to either a TOC or DOC determination, the term "OC" may be used.
For example, the LRB must not exceed 0.35 mg/L OC.
3.14 ORGANIC MATTER - A mixture of organic compounds (carbon-carbon, carbon-
hydrogen bonded compounds) naturally occurring and/or man-made that are found in
source water used by drinking water utilities. The quantity and quality of the OM in
source water is measured by TOC/DOC instrument systems or is measured by UVA.
3.15 QUALITY CONTROL SAMPLE (QCS) - A solution containing a known
concentration of an organic carbon compound(s) which is analyzed exactly like a
sample. The QCS is obtained from a source external to the laboratory and is different
from the source used for preparing the calibration standards. It is used to check
laboratory and instrument performance.
3.16 SOURCE WATER - Surface water or ground water that is used by a drinking water
utility to produce potable water for public consumption.
3.17 SPECIFIC UV ABSORBANCE AT 254 nm (SUVA) - A measure of DOC aromatic
content that is calculated by measuring the DOC and the UV absorbance at 254 nm of
a 0.45-fj,m filtered water sample. SUVA is calculated according to the equation given
in Section 12.2.
3.18 TOTAL CARBON (TC) - A measure of the OC and 1C contained in a water sample.
In this method, 1C is removed from the sample. Therefore, the TC reported by a TOC
instrument system will be equal to the TOC or DOC measurement.
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3.19 TOTAL ORGANIC CARBON (TOC) - The gross amount of organic matter (carbon
not removed by the 1C removal step) found in natural water. Suspended particulate,
colloidal, and dissolved organic matter are a part of the TOC measurement. For this
method, the TOC definition excludes the contribution of floating vegetative or animal
matter, and volatile organic matter found in source water. Settleable solids consisting
of inorganic sediments and some organic particulate are not transferred from the
sample by the laboratory analyst and are not a part of the TOC measurement.
3.20 TABLE OF ACRONYMS
Acronym
CB
CCC
COMM-BKS
COMM-SCS
DOC
FB
FD
FRB
1C
IDC
KHP
LFB
LFM
LRB
LRW
MRL
MSDS
OC-CAL
Term
calibration blank
continuing calibration check
commercial spectrophotometer background
solution
commercial spectrophotometer check
solution
dissolved organic carbon
filter blank
field duplicate
field reagent blank
inorganic carbon
initial demonstration of capability
potassium hydrogen phthalate
laboratory fortified blank
laboratory fortified matrix
laboratory reagent blank
laboratory reagent water
minimum reporting level
material safety data sheet
organic carbon calibration standard
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Acronym
OC-PDS
OCDL
QCS
scs
SDWA
SOP
SUVA
TC
TOC
UVA
Term
organic carbon primary dilution standard
organic carbon detection limit
quality control sample
spectrophotometer check solution
Safe Drinking Water Act
standard operating procedure
specific UV absorbance
total carbon
total organic carbon
UV absorbance
4.0 CONTAMINATION AND INTERFERENCES
4.1 SPECIAL CONSIDERATIONS FOR ONSITE UTILITY LABORATORIES -
Aerosols (foam and mist) from the operation of a water treatment plant contain
organic carbon and will contaminate glassware, reagents, sample collection
equipment, and onsite laboratory equipment if they are exposed to air at the water
utility. For an onsite laboratory, it is recommended that air be filtered and isolated
from organic fumes generated by petroleum products and combustion gases which
come from the operation of some water utility equipment. Work traffic in the onsite
laboratory should be minimized as it may produce dust containing organic matter that
will result in the contamination of unprotected samples and laboratory equipment.
4.2 All glassware must be meticulously cleaned. Wash glassware with detergent and tap
water, rinse with tap water followed by reagent water. Non-volumetric glassware may
then be heated in a muffle furnace at 425 °C for 2 hours to eliminate interferences.
Volumetric glassware should not be heated above 120 °C. Alternate cleaning
procedures, such as acid rinsing and heating at lower temperatures, maybe employed,
providing that these procedures are documented in a laboratory SOP and LRBs are
monitored as per Section 9.9.
4.3 Laboratory water systems have been known to contaminate samples due to bacterial
breakthrough from resin beds, activated carbon, and filters. Laboratory water systems
should be maintained and monitored frequently for carbon background and bacterial
growth. It is recommended that the LRW be filtered through a 0.22-fj,m filter
membrane to prevent bacterial contamination of TOC instrument systems, reagents,
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and samples. The LRW, sample transfer (pipet), glassware, and sample bottles are the
principle source for organic background in the analytical system. However, it is not
possible to control all sources of organic carbon contamination. Therefore, this
method allows for instrument background correction or adjusting the zero reference
point of the instrument for organic carbon background that is found in the analytical
system.2 There are many ways to correct for organic carbon background. Consult the
instrument manufacturer's operation manual for the instrument background correction
procedure. Subtraction of LRB or FB measurements from TOC, DOC, or UVA
sample results is not allowed.
4.4 High concentrations of OC, both man-made and naturally occurring, can cause gross
contamination of the instrument system, changes in calibration, and damage to valves,
pumps, tubing, and other components. It is recommended that analysis of a sample
known to have a concentration of OC > 10 mg/L OC be followed by the analysis of an
LRB. It is highly recommended that known samples containing OC concentrations
> 50 mg/L OC be diluted or not run on instruments used to analyze low-level drinking
water samples.
4.5 Source waters containing ionic iron, nitrates, nitrites, and bromide have been reported
to interfere with measurements of UVA absorbance at 254 nm.3 The concentration of
the interferences and their effect on the UVA cannot be determined as each unique
sample matrix may produce a different UVA response for the same concentration of
interference or combination of interferences. This method does not treat or remove
these interferences. Therefore, suspected or known interferences may affect results
and must be flagged in the SUVA result as "suspected UVA interferences."
4.6 Chloride exceeding 250 mg/L may interfere with persulfate oxidation methods.4'5
Some instrument systems may require increased persulfate concentration and
extended oxidation times. Consult with your instrument manufacturer's
representative or instrument operation manual for instrument settings and reagent
strengths when analyzing samples containing high levels of chloride.
4.7 Inorganic carbon (1C) interferes with TOC and DOC measurements. TOC instrument
bias due to incomplete 1C removal has been reported.6'7 If inorganic carbon is not
completely removed from the water sample, it will result in a positive or negative bias
depending on the way the instrument system calculates TOC (e.g., TOC =TC - 1C,
TC = TOC + 1C, or TOC = TC). When inorganic carbon (1C) is removed from the
sample prior to the TOC assay, as required in this method, TOC = TC and the method
bias is minimized.
5.0 SAFETY
5.1 Fast-moving source water, steep inclines, water conduits, and electrical hazards may
present special safety considerations for the sample collector. The sample collector
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should be aware of any potential safety hazards and take necessary precautions while
collecting samples.
5.2 Each chemical reagent used in this method should be regarded as a potential health
hazard. Exposure to these compounds should be minimized and/or avoided by active
participation in safety planning and good laboratory practices.8 Each laboratory is
responsible for maintaining a current awareness file of OSHA regulations9 regarding
the safe handling of the chemicals specified in this method. Material Safety Data
Sheets (MSDS) containing information on chemical and physical hazards associated
with each chemical should be made available to all personnel involved in the
chemical analysis.
5.3 Potassium persulfate is a strong oxidizing and corrosive reagent. The analyst should
avoid eye and skin contact by wearing eye/face protection, powderless gloves and
laboratory clothing. If body tissue comes in contact with this reagent, apply large
quantities of water for at least 15 minutes (see MSDS) while removing contaminated
clothing. This reagent may cause delayed burns. Seek immediate medical attention if
the area becomes irritated or burned. This reagent can also cause a fire or explosion if
it is allowed to come in contact with combustible materials.
5.4 Protect your hands by wearing laboratory disposable gloves during the preparation
and disposal of corrosive (acids and oxidants) laboratory reagents. Do not reuse
laboratory gloves that have been discarded or are suspected of being contaminated.
6.0 EQUIPMENT AND SUPPLIES
NOTE: Brand names, and/or catalog numbers are included for illustrative purposes
only. No endorsement is implied. Equivalent performance may be achieved using
apparatus, instrument systems, and reagents other than those that are illustrated
below. The laboratory is responsible for the assurance that alternate products,
apparatus, instrument systems, and reagents demonstrate equivalent performance as
specified in this method.
6.1 FILTER APPARATUS - Nalgene® or Corning® 250 mL Filter System, 0.45-um
Nylon (NYL) or Polyethersulfone (PES) Low Extractable Membrane/Polystyrene
Body with optional glass fiber prefilters (nominal 1 to 7 um). Packaging and filter
apparatus are recyclable (NALGE-NUNC International: Nalgene Labware CAT.
numbers NYL: 153-0045, PES: 168-0045). It is recommended that filter membranes
be hydrophilic 0.45-fj,m filter material.
NOTE: Alternate filter membranes (e.g., polypropylene, silver or Teflon®), apparatus
technologies such as cartridges, reusable filter bodies, syringe filters, and their
associated syringes, peristaltic pumps or vacuum pumps may be selected. The
complexity of an alternative filter apparatus is left to the analyst's ingenuity
providing that the apparatus meets quality control and initial demonstration of
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capability requirements as stated in Section 9.3.2, and that FB requirements are met
(Sect. 9.9). It is recommended that the analyst review the AW WA journal article
"Selecting filter membranes for measuring DOC and UV254", Karanfil, et. al.'°, prior
to the selection of an alternative filter membrane, apparatus, and wash procedure.
Karanfil tested 11 filter membranes (0.45-fim pore size and 47-mm disc size)
representing four different manufacturers and seven different types of filter materials
for both desorption and adsorption. Hydrophilic polyethersulfone (PES) filters
available from two manufacturers (Osmonics Micro-PES and Gelman Supor 450,
both 0.45 micron absolute pore size and 47-mm disc size) and a hydrophilic
polypropylene filter (Gelman GH Poly pro, 0.45 micron absolute pore size and 47-mm
disc size) were found to be the best options among those tested in the study.
6.2 INJECTION VIALS - Specially cleaned 40-mL glass vials, with cap and
polytetrafluoroethylene (PTFE)/silicone septa. Eagle-Picher TOC Certified, Cat. No.
40C-TOC/LL, Eagle-Picher Technologies®. These vials are specially cleaned by the
manufacturing process and certified to contain < 10 fig TOC. Vials maybe reused if
cleaned as per Section 4.2. The PTFE/silicone septa once pierced by the sample
injector must be discarded.
6.3 INSTRUMENT SYSTEMS - The TOC and UVA procedures allow for the use of
several different types or combinations of TOC instrumental system technologies.
Examples of typical TOC instrument systems, as well as a UV spectrophotometer, are
described below. Data from these instruments maybe found in Section 17. Only one
TOC instrument is required to perform this method.
6.3.1 TOC INSTRUMENT 1: UV/Persulfate/Wet Oxidation with
Permeation/Conductivity Detection. The lonics-Sievers® 800 TOC analyzer
is based on UV catalyzed persulfate digestion to produce CO2, which is
detected by a membrane permeation/conductivity detector.
6.3.2 TOC INSTRUMENT 2: Elevated Temperature/Catalyzed/Persulfate/Wet
Oxidation/Nondispersive Infrared Detection (NDIR). The O.I. Analytical®
TOC Model 1010 is based on elevated temperature (95-100°C) catalyzed
persulfate digestion to produce CO2, which is then detected by an NDIR
detector.
6.3.3 TOC INSTRUMENT 3: UV/Low Temperature/Persulfate/Wet
Oxidation/NDIR. The Tekmar-Dohrmann® Phoenix 8000 TOC analyzer is
based on UV catalyzed persulfate digestion to produce CO2, which is then
detected by an NDIR detector.
6.3.4 TOC INSTRUMENT 4: Catalyzed/Combustion Oxidation(680 °C)/NDIR.
The Shimadzu® model TOC-5000A analyzer is based on a catalyzed
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combustion in air or oxygen reagent gas to produce CO2, which is then
detected by an NDIR detector.
6.3.5 TOC INSTRUMENT 5: High Temperature Combustion Oxidation/NDIR.
The Thermo Environmental® ThermoGlas1M 1200 TOC is based on a dual
zone furnace with individually adjustable ovens from 700 to 1250 °C for final
high temperature combustion of the sample with air or oxygen reagent gas to
produce CO2, which is then detected by an NDIR detector.
6.3.6 UV SPECTROPHOTOMETER: The spectrophotometer is used for the UVA
determination only. The spectrophotometer must be able to measure UVA
(254 nm), with an absorbance from 0.0045 to at least 1.0 cm"1 UVA, and
accommodates a sample cell with a path length of 1, 5, or 10 cm.
6.4 LABORATORY REAGENT WATER TREATMENT SYSTEM - The LRW used for
the development of this method was generated using a Millipore®, Milli-Q Plus
Ultra-Pure Water Treatment System with a Q.22-um sterile pack filter capable of
producing organic carbon free (< 0.010 mg/L OC), ultrapure deionized water.11 The
maximum amount of OC allowed in the LRW for this method is 0.35 mg/L. When
purchasing a treatment system for general laboratory use, it is recommended that a
system be purchased capable of producing LRW of the above stated quality in order
to be of use in other laboratory analyses.
6.5 MUFFLE FURNACE - A muffle furnace capable of heating up to 425 °C.
6.6 FIELD SAMPLE pH TEST - Sample pH indicator test strips, non-bleeding
(colorpHast® Indicator Strips 0-2.5, cat. 9580), EM Science, 480 Democrat Road,
Gibbstown, N.J. 08027. Pocket pH test kits, pocket pH meters, or laboratory pH
meters are acceptable for field sample pH measurements.
6.7 PIPET, DISPOSABLE TRANSFER - Large volume bulb (15mL), non-sterile, with
flexible long stem polyethylene transfer pipet. "Sedi-Pet ™", Fisher Scientific® Cat.
13-711 -36. Pipets are used for sample transfer from the middle of a sample bottle
containing floating material (scum).
6.8 SAMPLE COLLECTION REAGENT BOTTLES - Specially cleaned, 1 -L Boston
round glass bottles with cap. Eagle-Picher TOC Certified, Cat. No. 112-01A/C TOC,
Eagle-Picher Technologies, LLC. These bottles are specially cleaned by the
manufacturing process and certified to meet EPA OSWER Directive # 9240.0-05A
"Specifications And Guidance For Contaminant-Free Sample Containers 12/92."
Amber bottles are preferred, but clear glass bottles may be used if care is taken to
protect samples from light. The laboratory may select glass bottles of any volume that
meet the utility and laboratory sample processing and quality control sampling needs.
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Glass bottles may be reused after cleaning (see Sect. 4.2 for glassware cleaning
instructions) or discarded.
6.9 SPARGE APPARATUS - N-EVAP™, Nitrogen Evaporator System Model 111,
Organomation Associates Inc. This apparatus is not used for its originally designed
purpose of evaporating sample extracts. In this method, the apparatus is used as a
sparging device. The stainless steel needles of the apparatus are lowered into the 40-
mL sample vials containing the TOC or DOC samples to remove inorganic carbon by
sparging with nitrogen gas.
Alternately, some TOC auto-samplers provide a pre-sparging or membrane 1C
removal option prior to injection of the sample into the TOC instrument system. The
analyst is encouraged to utilize these instrument options, if available. Another
alternative is for the laboratory analyst to fabricate a sparging apparatus. For
example, an apparatus may consist of copper tubing from a regulated gas source,
connected to a needle valve used for gas flow control, a length of silicone tubing with
a glass Pasteur pipet inserted into the tubing and a ring stand with clamp for
positioning the pipet. The Pasteur pipet is inserted into the sample bottle or vial to
remove inorganic carbon by sparging with nitrogen gas (Sect. 11.5). The complexity
of the alternative sparging apparatus is left to the analyst's ingenuity providing that
the apparatus meets quality control and initial demonstration of capability (1C
removal test) requirements as stated in Section 9.2.4.
6.10 VACUUM SOURCE - Aspirator, air flow or water flow, hand-operated or low
pressure electric vacuum pump, providing a vacuum of 15 inches of mercury (Hg) or
better. If an alternative choice is made, see note in Section 6.1.
6.11 VARIABLE PIPETTES - Programable automated pipettes. Rainin Instrument®
EDP-Plus Pipette 10ml, Cat. No. EP-10 mL; EDP-Plus Pipette 1000 uL, Cat. No. EP-
1000; EDP-Plus Pipette 100 \iL, Cat. No. EP-100, or manual variable pipets with
disposable tips having a calibrated range of 0 to 100-fj,L, 0 to 1000-p,L, and 0 to 10
mL.
6.12 VOLUMETRIC FLASK AND PIPETS - All volumetric glassware used in this
method are required to be "Class A".
6.13 WAVELENGTH VERIFICATION FILTER SET- Wavelength verification may be
provided by the instrument manufacturer, a scientific instrument service company, or
if this not practical, wavelength verification may be made by the laboratory using
certified spectrophotometric filter sets with values traceable to NIST. Fisher
Scientific Cat. No. 14-385-335, Spectronic No. 333150.
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7.0 REAGENTS AND STANDARDS
NOTE: The chemicals required for this method must be at least reagent grade.
Unless otherwise indicated, it is intended that all reagents shall conform to the
specifications of the Committee on Analytical Reagents of the American Chemical
Society (ACS) and/or ACS certified, when available. Some instrument manufacturers
provide reagents specifically prepared for the optimum performance of their TOC
instruments and provide calibration services and/or calibration standards. The
analyst is allowed to use these services or prepare reagents and/or standards
according to the instrument manufacturer's operation manual.
7.1 COMPRESSED GASES - Carbon dioxide free Ultra High Purity (UHP) grade
nitrogen gas or an optional Ultra-low level TOC gas delivery system. For combustion
based TOC systems, zero grade air and UHP grade oxygen maybe needed. The use
of lesser grades of compressed gases will result in high background noise in the TOC
instrument systems. The TOC Instrument 1 described in Section 6.3.1. does not
require compressed gasses for operation.
7.2 LABORATORY REAGENT WATER (LRW) - Water that has a TOC reading of
< 0.35 mg/L and < 0.01 cm'1 UVA. Although the LRW TOC and UVA limits in this
method are 0.35 mg/L and 0.01 cm"1' respectively, the system specified in Section 6.4
is capable of producing better quality organic carbon free, ultrapure deionized water.
For optimum performance, it is recommended that LRW with < 0.05 mg/L TOC and
< 0.0045 cm"1 UVA be used for this method. Alternatively, LRW may be purchased
(ACS HPLC grade or equivalent).
7.3 DISODIUM HYDROGEN PHOSPHATE, [Na2HPO4, CAS# 7558-79-4] -
Anhydrous, ACS grade or better.
7.4 O-PHOSPHOR1C ACID (85%), [H3PO4, CAS# 7664-38-2] - ACS grade or better.
7.5 POTASSIUM DIHYDROGEN PHOSPHATE, [KH2PO4, CAS# 7778-77-0]-
Anhydrous, ACS grade or better.
7.6 POTASSIUM HYDROGEN PHTHALATE (KHP), [C8H5O4K, CAS# 877-24-7] -
Anhydrous, ACS grade or better.
7.7 REAGENT SOLUTIONS FOR WET CHEMICAL OXIDATION - It is assumed that
each instrument manufacturer has optimized reagent solutions for their respective
instruments and has provided the instructions for the preparation of reagents in the
instrument's operation manual. NOTE: TOC Instrument 1 does not require gas
sparge of reagents as the manufacture provides reagent packs for the operation of the
instrument.
415.3- 14
-------
7.7.1 PERSULFATE REAGENT - Prepare this solution according to the instrument
manufacturer's instructions or purchase the solution from the instrument
manufacturer. If the laboratory prepares the solution, transfer the solution to
the instrument reagent bottle and cap. It is recommended that this solution be
sparged gently with carbon dioxide free UHP grade nitrogen gas for
approximately 1 hour. If the instrument system provides continuous sparge, it
is recommended that the reagent bottles be allowed to sparge for 10 minutes to
1 hour before operating the instrument. Self contained reagent packs or other
types of reagent systems may not require reagent sparging. Discard the
solution as per expiration time/date listed in the manufacturer's operation
manual.
7.7.2 PHOSPHORIC ACID SOLUTION - Prepare this solution according to the
instrument manufacturer's instructions or purchase the solution from the
instrument manufacturer. If the laboratory prepares the solution, transfer the
solution to the instrument reagent bottle and cap. It is recommended that this
solution be sparged gently with carbon dioxide free UHP grade nitrogen gas
for approximately 1 hour. If the instrument system provides continuous
sparge, it is recommended that the reagent bottles be allowed to sparge for 10
minutes to 1 hour before operating the instrument. Self contained reagent
packs or other types of reagent systems may not require reagent sparging.
Discard the solution as per expiration time/date listed in the manufacturer's
operation manual.
7.8 STANDARD SOLUTIONS
NOTE: Consult with the instrument manufacturer or operation manual for the
recommended concentrated acid used for preservation of standard solutions. The
concentrated acid used to preserve the standards is usually HCl, H2SO4, or H3PO4
depending upon the instrument operation manual recommendation. The acid used for
the standards must be the same as the one used for the samples. Standard solutions
may be alternatively prepared in larger or smaller volumes and concentrations as
needed for the calibration of instruments. Standard solutions may be prepared by
gravimetric or volumetric techniques. This section provides guidance for the
preparation of calibration solutions.
7.8.1 INORGANIC CARBON PRIMARY TEST SOLUTION (IC-TEST)
REAGENTS
7.8.1.1 AMMONIUM CHLORIDE, [NH4C1, CAS# 12125-02-9] - ACS grade
or better.
7.8.1.2 CALCIUM CHLORIDE DIHYDRATE, [CaCl2» 2H2O, CAS# 10035-
04-8] - ACS grade or better.
415.3- 15
-------
7.8.1.3 CALCIUM NITRATE TETRAHYDRATE, [Ca(NO3)2 • 4H2O, CAS#
13477-34-4] - ACS grade or better.
7.8.1.4 MAGNESIUM SULFATE HEPTAHYDRATE, [MgSO4- 7H2O,
CAS# 10034-99-8] - ACS grade or better.
7.8.1.5 POTASSIUM CHLORIDE, [KC1, CAS# 7447-40-7] - ACS grade or
better.
7.8.1.6 SODIUM BICARBONATE, [NaHCO3, CAS# 144-55-8] - ACS grade
or better.
7.8.1.7 SODIUM CHLORIDE, [NaCl, CAS# 7647-14-5] - ACS grade or
better.
7.8.1.8 SODIUM-META SILICATE NONAHYDRATE, [Ns^SiOj • 9H2O,
CAS# 13517-24-3]
7.8.1.9 SODIUM PHOSPHATE DIBASIC HEPTAHYDRATE, [Na2HPO4 •
7H2O, CAS# 7782-85-6] - ACS grade or better.
7.8.2 PREPARATION OF THE IC-TEST SOLUTION, 100 MG/L 1C - This
solution is used in the performance of the 1C removal sparging efficiency test
(Sect. 9.2.4 ). The ionic content of the IC-TEST mixture solution was chosen
from a previous investigation in which the authors wanted to simulate waters
likely to be found in waste treatment plants.12 Because the inorganic salts are
not soluble in a single concentrated solution, prepare four separate stock
solutions by diluting each of the following to one liter with LRW:
415.3- 16
-------
FLASK
(1L)
A
B
C
D
SALT
magnesium sulfate heptahydrate, MgSO4 • 7H2O
ammonium chloride, NH4C1
calcium chloride dihydrate, CaCl2 • 2H2O
calcium nitrate tetrahydrate, Ca(NO3)2 • 4H2O
potassium chloride, KC1
sodium chloride, NaCl
sodium bicarbonate, NaHCO3
sodium phosphate dibasic heptahydrate, Na^PO,, • 7H2O
sodium-meta silicate nonahydrate, Na2SiO3 • 9H2O
WEIGHT
(g)
2.565
0.594
2.050
0.248
0.283
0.281
2.806
0.705
1.862
Prepare a 102.5 mg/L 1C-TEST mixture, based on bicarbonate calculations
and impurities, by adding a 10-mL aliquot of each of the above solutions to a
40-mL vial. Add 40 p,L of H3PO4, HCI, or H2SO4, depending upon instrument
requirements (see note, Sect. 7.8), to the 40-mL injection vial. An IC-TEST
mixture of approximately 100 mg/L was chosen to represent the extreme
inorganic carbon concentration the analyst may encounter. Although the
mixture is turbid after preparation, clarification occurs after acidification.
7.8.3 ORGANIC CARBON PRIMARY DILUTION STANDARD (OC-PDS), 500
mg/L (1 mL = 0.5 mg OC) - Prepare an acid preserved (pH <2) OC-PDS by
pouring approximately 500 mL of LRW into a 1-liter volumetric flask, adding
1 mL of concentrated acid for preservation (see note, Sect. 7.8), carefully
transferring 1.063 g KHP into the LRW, stirring until it is dissolved, and then
diluting to the mark with LRW (1.0 mg KHP = 0.471 mg Organic Carbon).
Transfer this solution to a marked amber glass reagent bottle and cap for
storage. This solution does not require refrigeration for storage and is stable
for an indefinite period of time (6 months to a year). Replace the OC-PDS if
the instrument system fails to pass the QCS requirements (Sect. 9.11).
7.8.4 ORGANIC CARBON CALIBRATION (OC-CAL) - At least 4 calibration
concentrations and the CB (i.e., a minimum of 5 total calibration points) are
required to prepare the initial calibration curve. Prepare the calibration
standards over the concentration range of interest from dilutions of the OC-
PDS. The calibration standards for the development of this method were
prepared as specified in the table below. Calibration standards must be
415.3- 17
-------
prepared using LRW preserved to pH < 2 with concentrated acid (see note,
Sect. 7.8). Filtration of the CAL standards for DOC analysis is unnecessary,
since interferences from the filtration unit are monitored via the FB.
Therefore, the OC-CAL may be applied to TOC or DOC determinations. The
OC-CAL standards must be sparged, or otherwise treated for 1C removal, like
a sample following the procedure in Section 11.5.
PREPARATION OF CALIBRATION (OC-CAL) CURVE STANDARDS
CAL
Level
CB
1
2
3
4
5
6*
7*
Initial Cone, of
OC-PDS
(mg/L)
-
500
500
500
500
500
500
500
Vol. of
OC-PDS
(mL)
0
1.0
2.0
4.0
10.0
20.0
5.0
10.0
Final Vol. of
OC-CAL Std.
(mL)
1000
1000
1000
1000
1000
1000
100
100
Final Cone, of
OC- CAL Std.
(mg/L)
-
0.5
1.0
2.0
5.0
10.0
25.0
50.0
* Note: OC-CAL 6-7 are optional calibration standards for use when
operating the instrument in a higher concentration range.
The calibration blank (CB) is a "0.0 mg/L OC " standard which approximates
zero mg/L OC concentration plus the background carbon contributed from the
LRW. The CB is stored and treated the same as all other calibration
standards. When analyzed, the CB must not exceed 0.35 mg/L TOC.
7.8.5 Calibration standards maybe stored at room temperature in amber glass
bottles (Sect. 6.8) and/or in a dark cabinet (if clear glass used) for a period of
30 days. If stored OC-CALs are used to recalibrate the instrument during this
30 day period, the CB which has been stored with the OC-CALs must be
analyzed as a sample prior to recalibration. The CB must not exceed 0.35
mg/L OC. If the CB does not meet this criteria, the CB and OC-CALs may
have absorbed OC from the laboratory atmosphere and must be discarded.
7.9 COMMERCIAL SPECTROPHOTOMETER CHECK SOLUTION (COMM-SCS) -
The laboratory may use a commercially prepared COMM-SCS for the purpose of
checking the performance of the spectrophotometer. The analyst should purchase the
COMM-SCS in the absorbance range that is commonly observed for the samples
415.3- 18
-------
analyzed. The IN-SPEC™ optical standard and background solution for a 254 nm
spectrophotometric check is NIST traceable, and is available from GFS Chemicals,
PO Box 245, Powell, Ohio 43065.
7.9.1 COMMERCIAL SPECTROPHOTOMETER BACKGROUND SOLUTION
(COMM-BKS) - A background solution provided by the COMM-SCS
provider that is used to correct for stabilizing agents present in the COMM-
SCS.
7.10 LABORATORY PREPARED KHP-SPECTROPHOTOMETER CHECK
SOLUTIONS (KHP-SCS) - The laboratory may elect to prepare a KHP based
spectrophotometer check solution (KHP-SCS) for the purpose of checking the
performance of the spectrophotometer at the absorbance of the average UVA sample.
This requires the preparation of a buffered KHP solution having a known
concentration and a known absorbance at 254 nm. The analyst should prepare the
KHP-SCS that will provide an absorbance similar to the absorbance in the range (low,
mid, high) of the sample analyzed. NOTE: If the phosphate buffer reagents used
below have been exposed to laboratory humidity, it is recommended that potassium
dihydrogen phosphate (KH2PO4) and disodium hydrogen phosphate (Na2HPO4) be
dried for 1 hour at 105°C,
7.10.1 KHP-SCS-BLANK - Prepare a 1-L volumetric flask containing approximately
500 mL of LRW. Transfer and dissolve 4.08 g anhydrous KH2PO4 and 2.84 g
anhydrous Na2HPO4 in 500 mL. Dilute to the mark with LRW and transfer to a
1-L amber glass bottle.
7.10.2 KHP-SCS - Prepare the KHP-SCS that will provide an absorbance similar to
the absorbance of the samples analyzed. Prepare a 1-L volumetric flask
containing approximately 500 mL of LRW. Transfer and dissolve 4.08 g
anhydrous KH2PO4 and 2.84 g anhydrous Naj HPO4 into the 500 mL of LRW.
From the example calculation, or table located below (Sect. 7.10.2.1), transfer
the amount of OC-PDS (in mL) needed to produce the representative
absorbance of the sample into the buffered KHP-SCS and dilute with LRW to
the 1 L mark.
7.10.2.1 KHP-SCS, CONCENTRATION CALCULATION - Standard
Method 5910 B provides for a spectrophotometer check using a
correlation equation which was based on the analyses of 40-samples
of KHP solution.3 The correlation formula is as follows: UV254 =
0.0144 KHP + 0.0018. This formula may be algebraically solved for
the concentration of KHP, expressed as mg/L OC, needed to
produce a KHP-SCS for the observed sample absorbance as
follows:
415.3- 19
-------
KHP-OC cone. = (UV254 -0.0018) / 0.0144
Using the calculated KHP-OC concentration, determine the amount
of OC-PDS (Sect. 7.8.3, 1 mL = 0.5 mg OC) needed to produce a
known absorbance for the KHP-SCS. For example, if you typically
run samples that have an average UVA equal to 0.08 cm"1, you can
calculate the KHP in the following manner:
5.431 KHP mg/L as OC = (0.08 cm'1 UVA254 -0.0018) / 0.0144
The 5.431 mg/L is the same as 5.431 mg/L KHP. It follows that to
produce a 1-L KHP-SCS solution having a UVA absorbance of 0.08
cm"1, you will need 10.9 mL of OC-PDS as calculated below:
(5.431 KHP-SCS mg/L)(1000mL/L) / 500 OC-PDS mg/L= 10.9 mL of OC-PDS
In summary, 10.9 mL OC-PDS is needed to make a 1-L KHP-SCS
solution that will have a UVA absorbance of 0.08 cm"1.
Alternately, the following table, which is based on the above
calculation, can be used. From this table, cross reference the
amount of the OC- PDS (in mLs) needed to produce the desired
UVA for the KHP-SCS. Transfer the required amount of OC-PDS
into a 1 -L flask and dilute to the mark with LRW.
KHP-SCS Preparation
UVA@254nm
(cm -')
0.0738
0.1458
0.2898
0.4338
ORGANIC
CARBON (mg/L)
5
10
20
30
OC-PDS (mL
added per liter of
LRW)
10
20
40
60
7.10.3 Verify that the KHP-SCS-BLANK and the KHP-SCS buffered solutions are at
pH 7. Check the pH by placing a drop from the SCS bottle onto pH test paper.
Do not put the pH paper into the SCS bottle. Placing the pH paper in the
bottle will contaminate the sample with organic carbon. If this happens, the
spectrophotometer check solution must be discarded and a new solution
prepared in a clean bottle. If the buffered KHP-SCSs are not at a pH of 7, the
415.3-20
-------
solution must be discarded and a new solution made. Store these solutions at
approximately < 6 °C. These solutions are not preserved. In a sterile
environment these solutions may be stable for a month. However, the shelf life
of these solutions may be shortened as a result of microbial growth. Therefore,
it is recommended that the above solutions be made fresh weekly and/or be
replaced if any significant change in absorbance is noted.
8.0 SAMPLE COLLECTION, FILTRATION, AND HOLDING TIMES
NOTE: Consult with the instrument manufacturer or operation manual for the
recommended type of concentrated acid used for preservation ofTOC or DOC
samples. The concentrated acid used to preserve the sample is usually HCl, H2SO4, or
H3PO4 depending upon the instrument operation manual recommendation. The acid
used for the standards must be the same as the one used for the samples. Samples for
DOC and UVA analyses may be filtered in the field using alternate apparatus
technologies such as cartridges, reusable filter bodies, syringe filters, and their
associated syringes, peristaltic pumps or vacuum pumps providing that the filter blank
requirements are met (Sect. 9.9).
8.1 SUVA SAMPLE COLLECTION - SUVA is determined by the analysis of a DOC
sample and a UVA sample, together called the SUVA sample set. A single sample
may be collected and split for the DOC and UVA analyses or two individual samples
may be collected at the same time. For example: if the sample is to be determined by
two separate laboratories (i.e., one lab determines UVA and a second lab determines
the DOC), the sample collector may collect two representative samples for shipment.
A 1-L volume is recommended for the collection of DOC and UVA samples, but other
volumes may be collected depending on the sample volume needed for the filtration
apparatus used by the analyzing laboratory. The SUVA sample set is collected in clean
glass bottles by filling the bottle almost to the top. The sample set is NOT preserved
with acid at the time of collection. The sample set is delivered as soon as possible to
the laboratory and should arrive packed in ice or frozen gel packs. The sample set is
processed by the laboratory and stored at < 6 °C, until analysis. If there is no visible
ice or the gel packs are completely thawed, the laboratory should report these
conditions to the data user. Samples shipped that are improperly preserved, and/or do
not arrive at the laboratory within 48 hrs, cannot be used to meet compliance
monitoring requirements under the Safe Drinking Water Act (SDWA).
8.1.1 The DOC sample must be filtered in the field or in the laboratory within 48
hours of sample collection according to the procedure detailed in Section 11.4
prior to acidification and analysis. After filtration, the DOC sample is acidified
with 1 mL of concentrated acid per 1 L of sample or the sample is preserved by
drop wise adjustment to a pH < 2 (Sect. 8.3). The DOC bottle is capped and
inverted several times to mix the acid and is stored at < 6 °C. The sample must
be analyzed within 28 days from time of collection.
415.3-21
-------
8.1.2 The UVA sample must be filtered in the field or in the laboratory according to
the procedure detailed in Section 11.4. The sample used for the UVA
determination is not acidified. The UVA bottle is capped and stored at < 6 °C
for up to 48 hours from the time of collection. The UVA sample must be
analyzed within 48 hours from the time of collection.
8.2 TOC SAMPLE COLLECTION - The typical sample volume collected may vary from
40 mL to 1 L of sample. It is recommended that the sample collector coordinate the
size of collection volume with the needs of the analytical laboratory. If the TOC
sample is collected in a 40-mL injection vial, it is acidified to pH < 2 by adding 2
drops of concentrated acid. If the TOC sample is collected in a 1-L bottle, 1 mL of
concentrated acid is added or the sample is drop wise adjusted to a pH < 2 (Sect. 8.3).
TOC samples must be acidified at the time of collection. Cap the bottle or injection
vial and invert several times to mix the acid. The sample is delivered as soon as
possible to the laboratory and should arrive packed in ice or frozen gel packs. If there
is no visible ice or the gel packs are completely thawed, the laboratory should report
the conditions to the data user. Samples that are improperly preserved or shipped,
cannot be used for compliance monitoring under the SDWA. The sample is stored at
< 6 °C, until analysis. Stored and preserved samples must be analyzed within 28 days
from time of collection.
8.3 SAMPLE pH CHECK - The pH of the preserved sample (DOC, TOC only) or filtrate
should be checked to ensure adequate acidification for the preservation. This should
only be performed by an adequately trained sample collector. Check the pH by placing
a drop from the sample onto pH test paper. Do not put the pH paper into the sample
bottle. Placing the pH paper in the sample bottle will contaminate the sample with
organic carbon. If this happens, the sample or filtrate must be discarded and a new
sample collected.
9.0 QUALITY CONTROL
9.1 Each laboratory using this method is required to operate a formal quality control (QC)
program. QC requirements for TOC include: the initial demonstration of laboratory
capability (IDC) followed by regular analyses of continuing calibration checks (CCC),
independent quality control samples (QCS), laboratory reagent blanks (LRB), field
duplicates (FD), and laboratory fortified matrix samples (LFM). For this method, a
TOC laboratory fortified blank (LFB) is the same as a CCC (Sect. 10.3) and no LFB is
required. QC requirements for DOC include: the IDC followed by regular analyses of
CCCs, QCSs, filter blanks (FB), LFB, FDs, and LFMs.
For laboratories analyzing both TOC and DOC samples, only the DOC IDC
determination is required, as it is similar to, yet more rigorous than, the TOC IDC.
The IDC must be performed the first time a new instrument is used and/or when a new
analyst is trained.
415.3-22
-------
QC requirements for UVA analysis include: the performance of the IDC followed by
the regular analysis of spectrophotometer check solutions (SCS), FBs, and FDs. For
UVA analysis, no LFB or DL determination is required.
The control of instrument background is crucial prior to the performance of the IDC.
It is required that a critical evaluation be made of the instrument background2
associated with an instrument system before proceeding with the IDC. Once an
acceptable instrument background is established, it is safe to proceed with the IDC.
In summary, this section describes the minimum acceptable QC program, and
laboratories are encouraged to institute additional QC practices to meet their specific
needs. The laboratory must maintain records to document the quality of the data
generated. All users of this method are encouraged to write their own SOPs stating
exactly how their lab executes the method. A summary of QC requirements can be
found in Tables 17.5 and 17.6.
9.2 INITIAL DEMONSTRATION OF CAPABILITY FOR TOC DETERMINATION
9.2.1 INITIAL DEMONSTRATION OF LOW SYSTEM BACKGROUND - Before
any samples are analyzed, and any time a new set of reagents is used, prepare a
laboratory reagent blank (LRB) and demonstrate that it meets the criteria in
Section 9.9.
9.2.2 INITIAL INSTRUMENT CALIBRATION VERIFICATION - Prior to the
analysis of the IDC samples, calibrate the TOC instrument as per Section 10.2.
Verify calibration accuracy with the preparation and analysis of a QCS as
defined in Section 9.11.
9.2.3 INITIAL ORGANIC CARBON FLOW INJECTION MEMORY CHECK -
Inject the highest OC-CALused, followed by two injections of the LRB. If the
first LRB is > 0.35 mg/L OC and the second LRB is in QC compliance (i.e.,
< 0.35 mg/L OC), a memory problem is indicated. Therefore, an LRB may
need to be placed after every sample. If the instrument system provides a rinse
or system flush with LRB between injections, activate the event control settings
and repeat this section. If the memory problem persists, then an LRB must be
placed after every sample.
9.2.4 INORGANIC CARBON REMOVAL SPARGING EFFICIENCY TEST-
Various sample sparge times (3-10 minutes) and sparging flow rates have been
reported for the removal of 1C. 13 A multi-laboratory study reported large
variations and positive bias in analyses of solutions of standards containing
even small amounts of 1C, demonstrating the importance of 1C removal.14
Since 1C must be removed in order to reduce interferences with the TOC and
415.3-23
-------
DOC quantitation, an IDC of the 1C removal is performed. Please note: any
manipulation of the sample may inadvertently introduce organic carbon from
the apparatus.
Prepare an inorganic carbon mixture, IC-TEST solution, as specified in Section
7.8.2. Using the procedure outlined in Section 11.5, sparge at least three
portions of the acidified IC-TEST solution in the same manner, and of the same
volume, as field samples will be sparged. After the IC-TEST solution is treated
by the 1C removal apparatus, analyze the solution as an LRB for OC. The 1C
removal apparatus must produce an acceptable IC-TEST by meeting the LRB
requirements as stated in Section 9.9. These 1C removal parameters are then
used for all subsequent samples.
The sparging time recommended in Section 11.5.2 is based on a sparging study
with an N2 flow rate of approximately 200 mL/min and a pH of 2.0. The
following inorganic carbon concentration reduction was observed after the
external sparging of a 40-mL IC-TEST solution:
1C REMOVAL SPARGE EFFICIENCY STUDY
sparging time (minutes)
concentration 1C
(mg/L), measured as
OC interference
0
102.5
5
6.11
10
0.611
15
0.049
20
0.044
9.2.5
The LRB during the above study was < 0.05 mg/L, thus a 20-minute sparge
time ensured that no measurable organic carbon remained in the sample.
The above sparge efficiency table should be used only as a guide. The analyst
may find that a higher flow rate may reduce the time necessary to remove the
inorganic carbon to a level at or near the TOC measurements found in the LRB.
The IC-TEST solution is also used to test alternate 1C removal apparatus that
remove 1C by internal chemical treatment, alternate sparging procedures,
and/or membrane 1C removal. Any alternative procedure or 1C removal
apparatus must be tested using the IC-TEST solution and meet the LRB
requirements as stated in Section 9.9.
INITIAL DEMONSTRATION OF ACCURACY - The initial demonstration of
accuracy consists of the analysis of five (5) LFBs analyzed as samples at a
concentration between 2 to 5 mg/L OC. If DOC analysis is being performed,
the LFB must be filtered according to the procedure in Section 11.4. The
average recovery between 2 to 5 mg/L OC must be within ±20% of the true
415.3-24
-------
value. If ±20% of the true value is exceeded, identify and correct the problem
and repeat Sections 9.2.5 and 9.2.6.
9.2.6 INITIAL DEMONSTRATION OF PRECISION - Calculate the average
precision of the replicates in the Initial Demonstration of Accuracy (Sect.
9.2.5). The RSD% must be no greater than 20%. If the RSD% exceeds 20%,
identify and correct the problem and repeat Sections 9.2.5 and 9.2.6.
9.2.7 ORGANIC CARBON DETECTION LIMIT (OCDL) DETERMINATION -
The OCDL determination must be conducted over at least three (3) days with a
minimum of seven (n=7) replicate LFB analyses. Before conducting the initial
OCDL, the OC-CAL-1 standard is used to estimate the starting concentration
for the OCDL study. If DOC analyses are being performed, the low-level LFBs
must be filtered according to procedure in Section 11.4 prior to analysis for the
OCDL. If the instrument can easily detect the OC-CAL-1 standard, the analyst
should lower the concentration to a level so that the LFB produces a signal 2 to
5 times the background noise level of the instrument. It is recommended that
the LFB be fortified somewhere between 0.1 to 0.5 mg/L OC. All available
instrument digits are carried for the OCDL calculation. After completion of the
OCDL, the calculation is rounded up or down according to Standard Method
1050 B.15 The final result is reported in units used for the TOC or DOC
procedure and recorded to two significant figures in the instrument log book.
Calculate the OCDL using the equation:
Organic Carbon Detection Limit = St( n. u l. alpha = 0 99)
where:
t(n-i i-alpha = 099)= Student's t value for the 99% confidence level with n-1 degrees
of freedom (t = 3.14 for 7 replicates)
n = number of replicates, and
S = standard deviation of replicate analyses.
If the initial OCDL exceeds 0.35 mg/L or the mean recovery of the LFB used in
the OCDL determination exceeds + 50% of the true value, then the OCDL
determination must be repeated.
9.3 INITIAL DEMONSTRATION OF CAPABILITY FOR DOC DETERMINATION
9.3.1 Perform Sections 9.2.1 through 9.2.4 as prescribed for TOC.
9.3.2 INITIAL DEMONSTRATION OF FILTER MEMBRANE SUITABILITY -
Filter membranes are capable of affecting DOC and UVA analyses either by
desorption (leaching) of DOC and UV-absorbing materials from the filters to
415.3-25
-------
the samples, or by adsorption (uptake) of DOC and UV-absorbing materials
from the samples onto the filters. Filter membranes selected for DOC and
UVA measurements must not desorb nor adsorb significant DOC and UV-
absorbing materials. Desorption is minimized by pre-washing selected filters
as described in Section 9.3.2.2. Adsorption is minimized by filtering a portion
of the sample to waste before sample collection as described in Section 9.3.2.3.
Because the filtration of relatively turbid samples may cause filters to clog, pre-
filtration may be necessary and pre-filter preparation is described in Section
9.3.2.1. Due to the possibility of lot-to-lot variations in the levels of
contamination or adsorption, it is recommended that for each filter lot, the user
determine the amount of LRW needed to wash the filters and the amount of
sample that needs to be filtered and discarded prior to collection of filtrate
(filter-to-waste volume). A minimum of three filters (from each new lot)
should be cleaned and checked for desorption/adsorption prior to using the
filters for actual samples. This evaluation must be repeated when filters are
purchased from another manufacturer or when the type of filter being used is
changed.
9.3.2.1 PRE-FILTER PREPARATION - If the analyst anticipates that the UVA
and DOC sample will clog the 0.45-um pore size filter membrane
before enough filtrate can be collected, glass fiber pre-filters without
organic binders may be used. Karanfil et al10 suggested cleaning the
pre-filter by heating to 550 °C for one hour, cooling to room
temperature, then washing it with 500 mL of LRW. A 25-mL filter-to-
waste volume (Sect. 9.3.2.3) was also recommended. The pre-filters
must be demonstrated as acceptable using the procedures described
below in Sections 9.3.2.2 and 9.3.2.3. Depending on the design of the
filter apparatus, the analyst may be able to insert a pre-filter into the
filter apparatus. The pre-filter and filter apparatus could then be
washed as a unit, following the procedure in Section 9.3.2.2. Prefilter
adsorption and desorption may also be tested separately from the filter
membrane.
9.3.2.2 FILTER CLEANING - UV-absorbing materials and DOC are removed
from the filter and filter apparatus by passing LRW through the filter.
The volume of LRW required depends on the type and disc size of the
filter. For the filter apparatus used to generate the data in this method,
three successive rinses of 250 mL each (for a total of 750 mL) removed
UV-absorbing materials and DOC that could leach from the filter and
apparatus. (The Karanfil10 study found that a 500 mL wash was
sufficient to prepare the 47-mm disk filters recommended in their study
for DOC samples and a wash of 100 mL was sufficient for filters used
solely to prepare UVA samples.) Acceptable cleaning is demonstrated
by analyzing filter blanks (Sects. 11.4.3, 11.6) and meeting the criteria
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in Section 9.9. The volume of LRW required to obtain acceptable filter
blanks is then used to clean filters for analyses of all samples (Sect.
11.4). Filters that cannot be cleaned to meet the referenced criteria
must not be used in the preparation of DOC and UVA samples.
9.3.2.3 FILTER-TO-WASTE VOLUME DETERMINATION - In order to
minimize the loss of sample onto the filter by adsorption, a portion of
the sample must be used to saturate the adsorption sites on the filter
after it is cleaned according to Section 9.3.2.2. The amount of sample
filtrate that must be discarded prior to collecting filtrate for DOC and/or
UVA analyses will vary depending upon the type and size of filter and
the volume should be minimized in order to prevent filter clogging. A
25-mL filter-to-waste volume was recommended when using the
hydrophilic polyethersulfone and hydrophilic polypropylene filters of
47-mm disc size studied by Karanfil et al10 based on evaluations using
low-turbidity model waters prepared from preconcentrated humic and
fulvic materials.
In this method, a low-turbidity (i.e., TOC = DOC) finished water
sample can be used in the filter-to-waste determination. For
laboratories that are analyzing samples from a variety of sources, the
selected water should have a TOC concentration in the range of 1 to 3
mg/L. For laboratories that only analyze samples from one source, the
selected water should be a finished water with the lowest TOC that is
generally observed (NOTE: Depending on the quality of the source
water, this could be water with a TOC concentration much higher than
the 1 to 3 mg/L recommended for laboratories that are analyzing
samples from a variety of sources.)
A series of at least three filtrates are collected in separate containers for
the filter-to-waste volume determination. The volume of each filtrate is
determined based on the minimum volume required to make an
analytical determination. For example, if the DOC analysis requires 30
mL, then a series of at least three successive 30-mL filtrates should be
collected. For UVA, three successive 10-mL filtrates can be collected.
If DOC and UVA analyses are to be performed on the same filtrate,
then the volume of each filtrate should be adjusted to provide the
minimum volume necessary to accommodate both analyses (in the
above example, three successive 40-mL washes).
Each filtrate is analyzed according to the procedure in Section 11 and
the concentration is compared to the concentration of the unfiltered
sample. When the concentration of the filtrate is within ±15% of the
concentration measured in the unfiltered sample, then the recommended
415.3-27
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filter-to-waste volume is the sum of the volumes of that filtrate and any
previous filtrates in the series. For example, if the unfiltered sample
has a TOC concentration of 3.5 mg/L and the filtrate series (each filtrate
= 30 mL) have concentrations of 2.3, 3.2, and 3.4 mg/L, then a
minimum of 60 mL of sample should be filtered-to-waste prior to
collecting filtrate for DOC analyses. It is recommended that the filter-
to-waste volume be determined by performing this test on at least three
filters from each lot and averaging the results. Filters that require
large volumes of filter-to-waste should be avoided, because they will
be more subject to clogging prior to the collection of the necessary
volume of filtrate for analysis. The filter-to-waste volume that is
determined in this section must be used in the filtration procedure
described in Section 11.4.4.
9.3.3 Perform Sections 9.2.5 through 9.2.7 using filtered LFBs. The LFBs must be
prepared using the same procedure used to prepare samples (Sect. 11.4).
9.4 INITIAL DEMONSTRATION OF CAPABILITY FOR UVA DETERMINATION
9.4.1 INITIAL CHECK OF SPECTROPHOTOMETER PERFORMANCE - The UV
Spectrophotometer must be checked annually for 0 % transmittance,
wavelength accuracy, stray radiant energy, accuracy and linearity, and optical
alignment. It is recommended that the instrument performance be verified
through the manufacturer or a scientific instrument service company. If
independent verification of performance is not feasible, the laboratory may
acquire a certified spectrophotometric filter set and conduct the evaluation.
Wavelength verification is made using certified spectrophotometric filter sets
with values traceable to NIST. Using the filter set, test two wavelengths
between 220 and 340 nm. The instrument performance should be recorded in
the instrument log and be used to monitor the Spectrophotometer performance
over time. Follow the instrument manufacturer's operation manual when
measuring the acceptable wavelength transmittance limits.
9.4.2 Verify the Spectrophotometer performance according to the procedure as
outlined in Section 10.4.
9.4.3 Conduct the filter membrane suitability study described in Section 9.3.2 for
UVA.
9.5 CONTINUING CALIBRATION CHECK (CCC) - With each analysis batch, analyze a
Low-CCC at or below the MRL (Sect. 9.10) prior to TOC or DOC sample analysis.
Subsequent CCCs are analyzed after every ten samples and after the last sample. The
concentrations should be rotated to cover the instrument calibration range. A Mid-
CCC is required during every analysis batch. Acceptance criteria are as follows: Low-
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CCC, + 50% of true value; Mid-CCC, + 20% of true value; High-CCC, + 15% of true
value, see Section 10.3 for concentrations.
9.6 FIELD DUPLICATE (FD) - Within each analysis batch, a minimum of one set of field
duplicates must be analyzed (FD1 and FD2). Sample homogeneity and the chemical
nature of the sample matrix can affect analyte recovery and the quality of the data.
Duplicate sample analyses serve as a check on sampling and laboratory precision.
Two samples are collected at the field site and are treated exactly alike.
9.6.1 Calculate the relative percent difference (RPD) for duplicate measurements
(FD1 and FD2) using the equation:
FD1 -ED2
RPD =
(EDI + ED2)/2
9.6.2 Relative percent difference for field duplicates having an average concentration
of > 2 mg/L OC should fall in the range of < 20% RPD. If field duplicates in
this concentration range exhibit an RPD greater than 20%, results should be
flagged and the cause for the greater difference (e.g. incomplete 1C removal or
matrix interference), investigated. UVA readings should be < 10% RPD.
NOTE: Greater variability may be observed for samples with OC approaching
the OCDL.
9.7 LABORATORY FORTIFIED BLANK (LFB) - Within each DOC analysis batch,
analyze an aliquot of reagent water or other blank matrix which has been fortified with
KHP at a concentration of 1-5 mg/L OC. Recovery for the LFB must be within ±20%
of the true value. One LFB is required with each DOC analysis batch. For the DOC
analysis, an LFB is subjected to the same preparation and analysis as a sample,
including filtration (Sect. 11.4). The LFB is not determined for the TOC or UVA
measurements.
9.8 LABORATORY FORTIFIED MATRIX (LFM) - Within each TOC or DOC analysis
batch, an aliquot of one field sample is fortified with an aliquot of the OC-PDS (Sect.
7.8.3). The spike concentration used should result in an increase in the LFM
concentration of 50 to 200% of its measured or expected concentration. Over time,
samples from all routine sample sources should be fortified. For DOC analysis, the
LFM is filtered prior to acidification and analysis.
9.8.1 Calculate the percent spike recovery (%REC) using the equation:
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where
A = measured concentration in the fortified sample
B = measured concentration in the unfortified sample,
and
C = fortification concentration.
9.8.2 Recoveries may exhibit a matrix dependence. If the LFM recovery falls outside
of 70 to 130% for any fortified concentration, the analyst should suspect that
inorganic carbon was not properly removed (Sect. 11.5) from the sample or that
contamination or matrix interference exists (Sect. 4) and can not be removed.
If the source of the poor recovery can not be identified, the analyst should label
the sample report "suspect/contamination or matrix interference" to inform the
data user that the sample data quality is questionable but should not be rejected.
Failure to meet the recovery criteria after repeated sampling may suggest that
the sample matrix may need further study.
9.9 LABORATORY REAGENT BLANK (LRB) AND FILTER BLANK (FB) - Within
each analysis batch, a minimum of one LRB must be analyzed. For DOC and UVA
analysis, the FB serves as the LRB. If more than one lot of filters is used in a DOC or
UVA analytical batch, a FB must be analyzed for each lot. The analyst should be
aware that additional filter blanks, up to one for each sample, are required by some
regulations (e.g., 40 CFR 141.131(d)(4)(i)).
The LRB or FB is used to assess contamination from the laboratory environment and
background contamination from the reagents used in sample processing and is treated
exactly the same as a sample. The volume of the FB must be the same as the sample
volume. If UVA is to be determined, the FB (UVA-FB) must have an absorbance of
< 0.01 cm'1 UVA. The LRB and/or the FB (DOC-FB) must be < 0.35 mg/L OC. If
0.35 mg/L OC or 0.01 cm'1 UVA is exceeded, background carbon or reagent
contamination should be suspected. The cause for significant changes in the LRB or
FB value must be identified and any determined source of contamination must be
eliminated. For the FB, this may mean redetermination of filter membrane suitability
(Sect. 9.3.2). The cause of the contamination and the corrective action used to remedy
the problem is then recorded in the instrument log for future reference.
9.10 MINIMUM REPORTING LEVEL (MRL) - The OCDL should not be used as the
MRL. For TOC analysis, it is recommended that an MRL be established no lower than
the mean LRB measurement plus 3o, or two times the mean LRB measurement,
whichever is greater. For DOC analysis, the FB is substituted for the LRB. This value
should be calculated over a period of time, to reflect variability in the blank
measurements. Although the lowest calibration standard for OC may be below
the MRL, the MRL for OC must never be established at a concentration lower
than the lowest OC calibration standard.
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9.11 QUALITY CONTROL SAMPLE (QCS) - During the analysis of the IDC (Sects. 9.2,
9.3), each time new OC-PDS solutions are prepared (Sect. 7.8.3), or at least quarterly,
analyze a QCS from a source different from the source of the calibration standards.
The QCS is used to provide an independent verification of the method and the TOC
instrument system. To verify the stock or calibration solutions by comparison with the
QCS, dilute the calibration solution and QCS to a concentration in the mid range of the
calibration curve (approx. 1-5 mg/L TOC) in the same manner that the OC-CAL
standards are made (Sect. 7.8.4). Acceptable verification of the calibration is made
when the means of 3 analyses for both the calibration solution and QCS, having a
concentration range between 1 to 5 mg/L OC, agree to within ±20% of the true value.
If the measured QCS concentration is not within ±20% of the true value, the
calibration solution must be remade and/or the source of the problem must be
determined and corrected. Analysis of the QCS only applies to TOC and DOC
determination.
9.12 SPECTROPHOTOMETER CHECK REQUIREMENT - The performance of the
spectrophotometer is initially demonstrated using the procedure in Section 9.4.1. The
day-to-day performance of the spectrophotometer is checked using KHP-SCS (Sect.
7.10) or a commercially available SCS (COMM-SCS, Sect. 7.9) according to the
procedure in Section 10.4.
10.0 CALIBRATION AND STANDARDIZATION
10.1 INSTRUMENT SET UP AND OPTIMIZATION - Prior to calibrating the TOC
instrument, clean the instrument system with carbon dioxide free water and sparge
reagents with ultra high purity reagent gas as specified by the instrument manufacturer
to remove background carbon dioxide. NOTE: TOC Instrument 1 does not require
reagent gas for operation. Monitor the instrument background carbon dioxide levels
for at least 30 minutes or until the background signal reaches the manufacturer's
recommended level. The instrument should have a stable background and be free from
drift caused by CO2 contaminated gas or leaks in the system. Adjust instrument
temperature, reagent gas and reagent pump flow settings according to the
manufacturer's operation manual. Some instruments may require reagent priming runs
to clean the flow injection system and reduce carbon background. After the instrument
is judged to be stable, load the auto-injector or prepare to manually inject four LRB
samples and start the analysis. The data collected from the first injection of LRB is
discarded and is considered a system cleanup blank. The next three LRB injections
should produce consecutive readings that fall within 20% of their mean. If these
conditions are met, the instrument is ready for calibration. If not, use the OC-CAL-1
standard and repeat this section. If the three injections of OC-CAL-1 do not produce
consecutive readings that fall within 20% of their mean, the instrument is not ready to
operate and maintenance must be performed according to the instrument operation
manual before proceeding.
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10.2 CALIBRATION CURVE - A new calibration curve is generated when fresh standards
are made (Sect. 7.8.4) or when CCCs fall out of QC limits (Sect. 10.3). Use a CB and
at least four OC-CAL standards that span the concentration range of the samples to be
analyzed. For example, if the samples to be analyzed are low in concentration (a range
falling between 0.5 to 5 mg/L OC), prepare a calibration blank and a minimum of four
TOC calibration standards (CB, OC-CAL 1 - 4, see Sect. 7.8.4). The lowest
concentration calibration standard must be at or below the MRL, which may depend on
system sensitivity. Add an additional 40 p,L of H3PO4, HC1, or H2SO4, depending upon
instrument requirements (Sect. 8.0), to the 40-mL injection vial(s). Sparge the
calibration standards using the 1C removal procedure in Section 11.5 prior to
calibrating the instrument. Inject the standards from low to high concentration and
calibrate the instrument. Be careful not to extend the calibration range over too wide
of a concentration range as flow injection memory may cause analytical error (Sect.
9.2.3). The optional OC-CAL 6-7 maybe used when operating the instrument in a
higher concentration range.
NOTE: For instruments that have an internal calibration setting, the calibration is
checked by comparing the five point calibration curve with the internal calibration
point. If the five point calibration curve does not agree with the internal calibration
using the CCC criteria in Section 10,3, the internal calibration of TOC instrument
must be reset by the manufacturer or adjusted by the analyst, following the
manufacturer's operation manual.
10.2.1 With the instrument in the ready mode, initiate the automated instrument
calibration routine as per the instrument manufacturer's operation manual.
The computer generated calibration curve must have r2 > 0.993 before
proceeding with analyses. Ideally the instrument calibration should be
r2 > 0.9995 for best results. After the instrument system has been calibrated,
verify the calibration using the Continuing Calibration Check (CCC, Sect. 10.3)
and QCS (Sect. 9.11).
10.2.2 Save the data from the initial calibration curve and record it in the laboratory
notebook or instrument log. The initial calibration curve serves as a historical
reference so that future calibrations curves can be compared to determine if the
slope or sensitivity of calibration has changed. If the slope or sensitivity of the
instrument changes such that QC requirements cannot be met, consult the
instrument manual or lab SOP for corrective action, which may include
instrument maintenance and recalibration.
10.3 CONTINUING CALIBRATION CHECK (CCC) - Demonstration and documentation
of continuing calibration is required and must meet the requirements listed below. The
CCC solutions are made up weekly or just prior to a sample run and are prepared in the
same manner as the OC-CALs (Sect. 7.8.4). An analysis batch begins with the
analysis of a Low-CCC. CCCs are analyzed every 10 samples and must also include a
415.3-32
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Mid-CCC. Subsequent CCCs should alternate between low, medium, and high
concentrations, and must end the analysis batch. In summary, at least one Low-CCC
and one Mid-CCC is analyzed with each analysis batch in order to verify the
calibration curve. It is recommended that low, mid, and high CCCs be used to verify
the calibration curve over time.
10.3.1 Low-CCC - the concentration range may vary from as low as 2 times the
OCDL up to 0.7 mg/L OC. The Low-CCC is used to verify the low end of the
calibration and must be at or below the MRL, which may depend on system
sensitivity. The recovery for the Low-CCC must be within + 50% of the true
value.
10.3.2 Mid-CCC - the concentration is varied between 1.0 mg/L to 5.0 mg/L OC.
The purpose of this CCC is to verify the precision and accuracy at the
calibration range where critical source water treatment decisions are made.
The Mid-CCC concentration may be varied to meet changing regulatory
requirements. The Mid-range CCC must be within ±20% of the true value. If
it is not, the TOC instrument system must be recalibrated.
10.3.3 High-CCC - the concentration range is varied between 5 to 50 mg/L OC. The
selection of the High-CCC should be near the concentration of the highest OC-
CAL standard used. The purpose of this CCC is to bracket the concentration
the samples that are typically analyzed and to verify the upper range of the
calibration curve. High-CCC must be within ±15% of the true value. If it is
not, the TOC instrument system must be recalibrated.
10.4 SPECTROPHOTOMETER PERFORMANCE CHECK - The performance of the
spectrophotometer is initially demonstrated using the procedure in Section 9.4.1. The
day-to-day performance of the spectrophotometer is checked using KHP-SCS (Sect.
7.10) or a commercially available SCS (COMM-SCS, Sect. 7.9) prior to analyzing any
UVA samples using the procedure described below.
10.4.1 Using a transfer pipet fill the spectrophotometer cell with the COMM-BKS or
KHP-SCS-BLANK (Sects. 7.9.1, 7.10.1). Use this solution to zero the
spectrophotometer.
10.4.2 After the spectrophotometer is zeroed, empty the cell, clean with LRW, rinse
with methanol, dry with N2 or reagent grade air, and fill it with the KHP-SCS
or COMM-SCS.
10.4.3 Read the UVA of the KHP-SCS or COMM-SCS. The reading must be within
10% of the expected absorbance value. Record the absorbance of the KHP-
SCS or COMM-SCS in the spectrophotometer instrument logbook. Empty the
415.3-33
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cell, clean with LRW, rinse with methanol, and dry with N2 or reagent grade
air.
10.4.4 If the SCS absorbance criteria stated above cannot be met, discard the COMM-
SCS or the KHP-SCS and purchase new COMM-SCS or remake the KHP-
SCS. Repeat Section 10.4.
11.0 PROCEDURE
11.1 TOC/DOC SAMPLE INTEGRITY EVALUATION - It is important to analyze a TOC
or DOC sample as directly and as soon as possible. Sample handling and preparation
should be minimized. Upon receiving the sample from the field, the analyst must
determine if the sample was treated and stored according to instructions found in
Section 8.
11.2 OPTIONAL TREATMENT FOR TOC/DOC SAMPLE MATRIX LOSS - Aquatic
humic substances precipitate at pH below 2 16, and may move to glass vessel walls or
instrument tubing. If the analyst suspects that humic substances have precipitated
(which sometimes occurs in blackwaters)14 or flocked to the bottom of the sample
container, the sample is degassed by sparging to remove 1C as directed in Section 11.5.
The sample is then split into two portions. One portion is left at a pH <2, and the pH
of the second portion is adjusted to pH 5 to 7 in order to increase the solubility of
hydrophobic matter in the sample. Both samples are allowed to sit capped for 1A hour
before further sample processing. These samples are treated in the same manner as
field duplicates (FD), Section 9.6. The results of both split samples and corresponding
pH values should be reported to the data user.
11.3 TOC SAMPLE PREPARATION - Remove the TOC sample from cold storage and
allow the sample to come to room temperature. Determine if the sample has been
preserved by acidification to a pH <2 by placing some drops on pH paper or by
pouring some of the sample into a small beaker and checking it with a glass or solid-
state pH electrode. Do Not put the pH paper or electrode into the sample bottle. If the
pH is greater than 2, discard the sample.
11.3.1 TYPICAL TOC SAMPLE PRE-TREATMENT - Samples that appear to be
low in particulate and suspended material are generally transferred directly to
the 40-mL injection vial. If the sample appears to contain sediment or floating
material, allow the sample to sit for a minute or two to allow sediment material
to settle back to the bottom of the bottle. After allowing the sample to settle,
transfer the sample from the middle of the bottle using a disposable pipet to the
injection vial. Add 40 uL of H3PO4, HC1, or H2SO4 depending upon instrument
requirements (Sect. 8.0) to the 40-mL injection vial and label it.
11.3.2 Proceed to Section 11.5, for 1C removal.
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11.4 SUVA SAMPLE PREPARATION - If SUVA is not being determined, proceed to
Section 11.5. The SUVA determination consists of paired sample analyses composed
of a DOC sample and a UVA sample. DOC and UVA samples may be taken from the
same bottle, or may be taken from separate field duplicate bottles. Remove the DOC
and UVA sample(s) from cold storage and allow them to come to room temperature.
The laboratory is required to document any use of alternative filters, apparatus (see
note, Sect. 6.1), or changes in the SUVA sample preparation procedure. All QC
requirements (Sect. 9) must be met.
11.4.1 Samples for DOC and UVA analysis are NOT acidified in the field. The DOC
sample is acidified after filtration as described below and the UVA sample is
not acidified at all. Determine if the sample(s) was accidentally preserved by
placing a few drops from the sample on pH paper or by pouring some of the
sample into a small beaker and checking it with a glass or solid-state pH
electrode. Do Not put the pH paper or electrode into the sample bottle.
Placing the pH paper or electrode into the sample bottle will contaminate the
sample solution with organic carbon. If this happens, the sample must be
discarded. If the UVA sample pH is <2, check to make sure that the sample is
actually for the UVA determination. It is possible that this sample is a TOC or
filtered DOC sample and was mislabeled as a UVA sample. If the sample set
was not mislabeled or switched but accidentally preserved, the sample must be
discarded. The analyst must check the date and time of collection to ensure
that the sample holding times listed in Section 8.1 have been met.
11.4.2 Filter Cleaning - Cleaning the filter apparatus, including the filter, removes
trace organic compounds that may have been left behind in the manufacturing
process. This cleaning must be done immediately prior to sample filtration.
Rinse the filter with LRW, using the cleaning procedure used to determine
filter membrane suitability (Sect. 9.3.2.2), including the cleaning of the pre-
filter if a pre-filter is necessary.
11.4.3 Filter Blank (FB) - Use a clean filter apparatus (prepared in Sect. 11.4.2) and
filter an aliquot of LRW into an injection vial for the DOC analysis and another
aliquot of LRW into a vial for UVA analysis (Figure 1). FB volume must be
the same as the sample volume collected in Section 11.4.4. During the
development of this method, approximately 250 mL of LRW was filtered and
aliquots were poured into two 40-mL injection vials and labeled as the DOC
and UVA FBs. If the DOC and UVA analyses are coming from two separate
bottles, a filter apparatus will be needed for each bottle and an FB should be
prepared from each apparatus. Add 40 p,L of H3PO4, HC1, or H2SO4 (as
required by the various instrument types, Sect. 8.0) to the 40-mL DOC-FB
injection vial. Do not acidify the UVA-FB injection vial. These vials are
paired with the respective SUVA sample and retained for DOC-FB and UVA-
FB analyses.
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11.4.4 Sample Preparation - Reassemble the filter apparatus. Pour enough sample
onto the filter to saturate any adsorption sites, as determined according to the
filter-to-waste procedure in Section 9.3.2.3. Apply vacuum until no visible
water remains on the filter. Remove the vacuum, swirl the apparatus with
sample filtrate, disassemble, and discard the sample filtrate rinse. Reassemble
the filter apparatus and pour an additional aliquot of sample into the top of the
filter apparatus. Attach the vacuum and retain the filtrate. Pour one aliquot
into a 40-mL injection vial and label it to identify it as the DOC sample. Pour
a second aliquot into a 40-mL injection vial and label it to identify it as the
UVA sample. Add 40 ^L of H3PO4, HC1, or H2SO4 to the 40-mL DOC
injection vial. Do not acidify the UVA injection vial. As with the DOC and
UV FBs (Sect. 11.4.3), separate filter apparatus may be used for the DOC and
UVA samples, in which case the filtrate need not be split into two aliquots.
For a sample that is difficult to filter, an additional filter apparatus or the
optional pre-filter insert apparatus may be used. The use of additional filters
may require the collection of additional FBs, collected as specified in Section
11.4.3. The resulting additional DOC-FB, UVA-FB sample filtrates are
collected, their volumes composited and then placed into their respective
injection vials.
11.5 INORGANIC CARBON REMOVAL - All OC-CALs, TOC and DOC samples,
DOC-FBs, and LRBs must be treated to remove 1C prior to OC analysis. UVA
samples and UVA-FBs are not sparged with nitrogen gas or otherwise treated to
remove 1C prior to analysis (See Figure 2). The laboratory is required to document
any use of alternative 1C removal apparatus (Sects. 6.9, 11.5.2) or changes in the 1C
removal procedure. All quality control requirements (Sect. 9.2.4) must be met.
NOTE: If a sparging apparatus is used, it should be isolated from the organic
laboratory and be free of organic contaminants.
11.5.1 CLEANING SPARGING APPARATUS: Before initial use and immediately
after each use, the sparging apparatus must be cleaned. With the nitrogen
turned off, dip the stainless steel needles in a 40-mL injection vial containing
dilute acid (40 uL H3PO4, HCL, or H2SO4 per 40 mL LRW). Take the needles
out of the dilute acid and turn the nitrogen back on to flush out any residual
dilute acid. If disposable pipettes are used as part of the sparging apparatus,
discard the pipettes after each use instead of attempting to clean and reuse
them.
11.5.2 SPARGING PROCEDURE: Submerge the apparatus needles used to sparge
the samples near the bottom of the 40-mL sample injection vial. Data
generated for this method were generated by externally sparging the acidified
samples with nitrogen gas, at 100 to 200 mL/minute, for 20 minutes per 40-mL
sample injection vial. Some instrument companies provide optional inorganic
415.3-36
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carbon removal apparatus that may produce an efficient means for the removal
of 1C. The laboratory must demonstrate sparging efficiency by the performance
of the 1C removal sparging efficiency test (Sect. 9.2.4 ) and meeting the LRB
requirements as stated in Section 9.9.
11.6 SAMPLE ASSAY
11.6.1 TOC/DOC Sample Analysis - This is accomplished by placing into the
injection vial tray a series of 40-mL injection vials usually containing any or all
of the following types of samples: LRB, DOC-FB, CB, OC-CAL(s), CCC s
(Low, Mid or High concentration), field samples, FD1 & FD2, LRB between
samples if needed as specified in Section 9.2.3, LFB, LFM, and the QCS. The
DOC-FB maximum allowable background concentration is 0.35 mg/L OC.
The injection tray is placed into the instrument, the run is initiated, and the
results of analyses are recorded.
11.6.2 UVA ANALYSES - If the spectrophotometer performance meets the SCS
absorbance criteria as stated in Section 10.4, zero the instrument with the
empty cell. Next fill the cell with the UVA-FB and read the absorbance. The
UVA-FB's maximum allowable background absorbance is 0.01 cm"1 UVA. If
0.01 cm"1 UVA for the UVA-FB is exceeded, the cause must be identified and
any determined source of contamination must be eliminated. The
spectrophotometer performance must then be rechecked (Sect. 10.4). The
laboratory should also check the initial zero each time 10 samples have been
read. Rinse the spectrophotometer cell with a small amount of the UVA
sample or UVA-FB by directly pipetting or pouring the sample into the
spectrophotometer cell and discarding the rinse. Refill the spectrophotometer
cell, carefully clean the cell window, and place in the spectrophotometer cell
holder. Alternatively, flow cells maybe used, filled and flushed as needed.
Measure the UVA and record. If field duplicates are collected, the FD1 & FD2
sample filtrates are also read and recorded.
12.0 DATA ANALYSIS AND CALCULATION
12.1 TOC DIRECT READING: The TOC concentration is calculated by the automated
instrument system's software. Follow the instrument manufacturer's operation manual
when making instrument response adjustments for instrument system blank
corrections. The TOC calculation assumes that the sample has been properly
preserved, that only a trace amount of 1C remains following the 1C removal procedure,
and that any remaining 1C will not contribute to the TOC measurement and result in a
calculation error. Some instrument systems calculate TOC from the difference of the
total carbon (TC) minus the 1C. The analyst is reminded that the 1C in the sample is
removed prior to sample analysis. Therefore, the reported TC is equal to, and the same
415.3-37
-------
as, the TOC value (TOC =TC) and is read directly from the instrument's computer or
printout.
12.2 SUVA CALCULATION: Follow the instrument manufacturer's operation manual
instructions when making instrument response adjustments for instrument system
blank correction. As in the above TOC calculation, the analyst is reminded that the 1C
of the DOC sample is removed prior to analysis. After filtration, the TOC instrument
value is equal to the DOC. The SUVA is then calculated from the DOC & UVA data
that results from the procedure as described above (Sects. 11.6.1, 11.6.2). The UVA of
the sample in cm"1 is divided by the DOC of the sample, multiplied by 100 cm/M and
either reported in units of L/mg-M or as "SUVA". The SUVA is calculated as follows:
SUVA (L/mg-M) = UVA(cm-1) / DOC (mg/L) * 100 cm/M
UVA Calculation: UVA = A /d
where:
UVA = The calculated UV absorbance of the sample in
absorbance units (cm"1).
A = The measured UV absorbance at 254 nm of the
sample that is filtered through a 0.45-fj,m filter
media.
d = The quartz cell path length in cm.
NOTE: A Filter Blank (FB) is used to monitor background carbon
contamination (Sect. 11.4.3) and is not subtracted from the DOC and
UVA measurements.
12.3 Calculations should utilize all available digits of precision, but final reported
concentrations should be rounded to two significant figures (one digit of uncertainty).
The final calculation is rounded up or down according to Standard Method 1050B.15
13.0 METHOD PERFORMANCE
NOTE: Data presented in Section 17 are from single-laboratory determinations. All
available digits were used for calculation and the calculations were rounded prior to
entry in the tables. The data were reported to as many as three significant figures to
give the reader a better understanding of method performance.
13.1 Table 17.1 summarizes the 3-day organic carbon detection limit (OCDL) study for five
TOC instruments systems. The DOC determination ranged from 0.02 to 0.08 mg/L
OCDL and the TOC determination ranged from 0.04 to 0.12 mg/L OCDL. All source
415.3-38
-------
water samples reported in Section 13 and the Section 17 Tables were sparged for 20
minutes to remove inorganic carbon interferences.
13.2 Table 17.2 and associated sub-tables illustrate the single instrument precision and
accuracy for each of the five TOC instrument technologies.
13.3 Tables 17.3 and 17.4 illustrate the instrument differences and performances for five
TOC instruments analyzing seven different source water matrices.
13.4 In all cases, the TOC instruments had difficulty in analyzing the Saint Leon well water.
The Saint Leon well water had a moderately high inorganic carbon content of
approximately 100 mg/L 1C, and a low organic carbon content of 0.2 to 0.6 mg/L OC.
The Saint Leon well water organic carbon content was near the organic carbon
detection limit. The low OC concentration produced the greatest differences between
instrument responses. For low TOC samples with high 1C, differences between
instrument responses may be more apparent due to possible 1C interference.
13.5 The TOC, DOC and SUVA procedures of this method are dependent on the operation
manual for the TOC instrument system and the UV spectrophotometer as provided by
the respective instrument manufacturers. However, all performance criteria and
quality control requirements described in this method, as summarized in Tables 17.5
and 17.6, must be met.
14.0 POLLUTION PREVENTION
14.1 Pollution prevention encompasses any technique that reduces or eliminates the
quantity or toxicity of waste at the point of generation. Numerous opportunities for
pollution prevention exist in laboratory operations. The EPA has established a
preferred hierarchy of environmental management techniques that places pollution
prevention as the management option of first choice. Whenever feasible, laboratory
personnel should use pollution prevention techniques to address their waste generation.
When wastes cannot be feasibly reduced at the source, the Agency recommends
recycling as the next best option.
14.2 For information about pollution prevention that may be applicable to laboratories and
research institutions, consult Less is Better: Laboratory Chemical Management for
Waste Reduction, available from the American Chemical Society's Department of
Government Relations and Science Policy, 1155 16th Street N.W., Washington D.C.
20036,(202)872-4477.
14.3 For recycle information, contact the US EPA, Pollution Prevention and Waste Wise
program, http://www.epa.gov/wastewise/.
415.3-39
-------
15.0 WASTE MANAGEMENT
15.1 The U.S. Environmental Protection Agency requires that laboratory waste management
practices be conducted consistent with all applicable rules and regulations. The
Agency urges laboratories to protect the air, water, and land by minimizing and
controlling all releases from hoods and bench operations, complying with the letter and
spirit of any sewer discharge permits and regulations, and by complying with all solid
and hazardous waste regulations, particularly the hazardous waste identification rules
and land disposal restrictions. For further information on waste management, consult
The Waste Management Manual for Laboratory Personnel, available from the
American Chemical Society at the address listed in Section 14.2.
15.2 The laboratory should consult with local authorities prior to disposal of any waste to
publicly owned treatment works (POTW) and receive permission for that disposal.
16.0 REFERENCES
1. Glaser, J. A.; Foerst, D. L.; McKee G. D.; Quave, S. A.; Budde, W. L. Trace Analyses
for Wastewaters. Environ. Sci. Technol. 1981,15 (12), 1426-1434.
2. Benner, R.; Storm, M. A Critical Evaluation of the Analytical Blank Associated with
DOC Measurements by High-Temperature Catalytic Oxidation. Mar. Chem. 1993, 41,
153-160.
3. Standard Method 591 OB: Ultraviolet Absorption Method. In Standard Methods for the
Examination of Water and Wastewater, Eaton, A. D.; Clesceri, L. S.; Greenberg, A. E.,
Eds.; American Public Health Association; Washington, DC, 1995; 19th ed.
4. Aiken, G.R. Chloride Interference in the Analysis of Dissolved Organic Carbon by the
Wet Oxidation Method. Environ. Sci. Technol 1992, 26 (12), 2435-2439.
5. Sakamoto, T.; Miyasaka, T. TOC Analysis Study Confirming the Accuracy of a Method
for Measuring TOC by Wet Oxidation. Ultrapure Water 1987, 24-31.
6. Potter, B. B.; Wimsatt, J. C. Preprints of Extended Abstracts, Vol 42 (1), 223rd National
Meeting of the American Chemical Society, Orlando, FL, April 7-11, 2002; American
Chemical Society Division of Environmental Chemistry: Cape Girardeau, MO, 2002;
Paper 60, 559-564.
7. Aiken, G.; Kaplan, L. A.; Weishaar, J. Assessment of Relative Accuracy in the
Determination of Organic Matter Concentrations in Aquatic Systems. J. Environ. Monit.
2002, 4, 70-74.
415.3-40
-------
8. American Chemical Society, Committee on Chemical Safety. Safety in Academic
Chemistry Laboratories, Vol. 2, Accident Prevention for Faculty and Administrators, 7th
ed.; American Chemical Society: Washington, DC, 2003.
9. Occupational Exposure to Hazardous Chemicals in Laboratories. Code of Federal
Regulations, Part 1910.1450, Title 29, 2001.
10. Karanfil, T.; Erdogan, I; Schlautman, M. A. Selecting Filter Membranes for Measuring
DOC and UV254. J. Am. Water Works Assoc. 2003, 95 (3), 86-100.
11. Standard Method 1080: Reagent-Grade Water. In Standard Methods for the Examination
of Water and Wastewater, Eaton, A. D.; Clesceri, L. S.; Greenberg, A. E., Eds.; American
Public Health Association; Washington, DC, 1995; 19th ed.
12. Schaffer, R. B.; Van Hall, C. E.; McDermott, G. N.; Earth, D.; Stenger, V. A.; Sebesta,
S. J.; Griggs, S. H. Application of a Carbon Analyzer in Waste Treatment. J. Water
Pollut. Control Fed. 1965, 37 (11), 1545-1566.
13. Van Hall, C. E.; Earth, D.; Stenger, V. A. Elimination of Carbonates from Aqueous
Solutions Prior to Organic Carbon Determination. Anal. Chem. 1965, 37 (6), 769-771.
14. Kaplan, L.A. Comparison of High-Temperature and Persulfate Oxidation Methods for
Determination of Dissolved Organic Carbon in Freshwaters. Limnol. Oceanogr. 1992, 37
(5), 1119-1125.
15. Standard Method 1050B: Significant Figures. In Standar d Methods for the Examination
of Water and Wastewater, Eaton, A. D.; Clesceri, L. S.; Greenberg, A. E., Eds.; American
Public Health Association; Washington, DC, 1995; 19th ed.
16. Standard Method 5510: Aquatic Humic Substances. In Standard Methods for the
Examination of Water and Wastewater, Eaton, A. D.; Clesceri, L. S.; Greenberg, A. E.,
Eds.; American Public Health Association; Washington, DC, 1995; 19th ed.
415.3-41
-------
17.0
TABLES, DIAGRAMS, FLOWCHARTS, AND VALIDATION DATA
17.1 ORGANIC CARBON DETECTION LIMIT (OCDL)a
Dissolved Organic Carbon (DOC), mg/L
Instrument
1
2
3
4
5
Fortified
Cone."
0.130
0.125
0.250
0.130
0.250
Mean
Recovered
Cone.
0.155
0.116
0.249
0.125
0.233
%RSDC
11
22
4
5
9
%RECd
119
93
100
96
93
OCDL
0.054
0.082
0.035
0.018
0.068
Total Organic Carbon (TOC), mg/L
Instrument
1
2
3
4
5
Fortified
Cone.
0.130
0.125
0.250
0.130
0.250
Mean
Recovered
Cone.
0.159
0.145
0.259
0.130
0.251
%RSDC
14
26
8
9
7
%RECd
122
116
104
100
100
OCDL
0.071
0.118
0.061
0.036
0.059
a Organic Carbon Detection Limits were determined by analyzing 7 replicates over 3 days.
b LRW fortified as specified in the table.
0 %RSD = percent relative standard deviation
d %REC = percent recovery
INSTRUMENT:
1: UV/Persulfate/Wet Oxidation with Permeation/Conductivity Detection
2: Elevated Temperature/Catalyzed/Persulfate/Wet Oxidation/Nondispersive
Infrared Detection (NDIR)
3: UV/Low Temperature/Persulfate/Wet Oxidation/NDIR
4: Catalyzed/Combustion Oxidation(680 °C)/NDIR
5: High Temperature Combustion Oxidation/NDIR
415.3-42
-------
17.2 SINGLE TOC INSTRUMENT PRECISION AND ACCURACY
17.2.1 TOC Instrument 1: UV/persulfate wet oxidation with
permeation/conductivity detection
Dissolved Organic Carbon, mg/La
Source
Water
Boulder Creek
Shingobee R.
Bolten Well
Ohio R. (Fernbank)
Muddy Creek
Great Miami R.
Saint Leon Well
Unfortified Sample
Cone.
Mean
1.63
2.98
1.27
2.79
3.81
3.18
0.53
%RSD
1.62
0.19
0.00
0.36
0.15
0.00
0.97
Fortified Sample Cone.
Mean
12.2
13.5
12.0
13.6
14.6
13.7
11.0
%REC
105
105
107
108
108
104
104
Total Organic Carbon, mg/La
Source
Water
Boulder Creek
Shingobee R.
Bolten Well
Ohio R. (Fernbank)
Muddy Creek
Great Miami R.
Saint Leon Well
Unfortified Sample
Cone.
Mean
1.73
3.16
1.32
3.02
4.24
3.51
0.66
%RSD
0.33
0.18
0.44
0.57
0.00
0.33
0.52
Fortified Sample Cone.
Mean
12.1
13.0
11.4
13.2
14.6
13.8
11.1
%REC
103
98
100
102
103
102
104
N = 3, samples fortified at lOmg/L OC using KHP
415.3-43
-------
17.2 SINGLE TOC INSTRUMENT PRECISION AND ACCURACY, cont'd.
17.2.2 TOC Instrument 2: Elevated temperature/catalyzed/persulfate wet
oxidation/NDIR
Dissolved Organic Carbon, mg/La
Source
Water
Boulder Creek
Shingobee R.
Bolten Well
Ohio R. (Fernbank)
Muddy Creek
Great Miami R.
Saint Leon Well
Unfortified
Sample Cone.
Mean
1.40
2.58
1.04
2.41
3.25
2.68
0.40
Fortified Sample Cone.
Mean
11.8
13,3
12.6
13,3
14.3
13,4
10.6
%REC
104
106
105
108
110
107
101
Total Organic Carbon, mg/La
Source
Water
Boulder Creek
Shingobee R.
Bolten Well
Ohio R. (Fernbank)
Muddy Creek
Great Miami R.
Saint Leon Well
Unfortified
Sample Cone.
Mean
1.38
2.62
1.05
2.46
3.41
2.89
0.38
Fortified Sample Cone.
Mean
11.2
12.7
11.4
13,1
13,8
13,2
10.5
%REC
98
100
103
106
104
103
102
a N = 2, samples fortified at lOmg/L OC using KHP
415.3-44
-------
17.2 SINGLE TOC INSTRUMENT PRECISION AND ACCURACY, cont'd.
17.2.3 TOC Instrument 3: UV/low temperature/persulfate wet oxidation/NDIR
Dissolved Organic Carbon, mg/La
Source
Water
Boulder Creek
Shingobee R.
Bolten Well
Ohio R. (F embank)
Muddy Creek
Great Miami R.
Saint Leon Well
Unfortified Sample
Cone.
Mean
1.52
2.71
1.18
2.50
3.38
2.91
0.56
%RSD
1.81
1.10
1.76
0.74
0.81
0.64
0.88
Fortified Sample Cone.
Mean
11.5
13.2
11.3
13.1
14.0
13.1
10.7
%REC
100
104
101
106
106
102
101
Total Organic Carbon, mg/La
Source
Water
Boulder Creek
Shingobee R.
Bolten Well
Ohio R. (F embank)
Muddy Creek
Great Miami R.
Saint Leon Well
Unfortified Sample
Cone.
Mean
1.47
2.72
1.16
2.58
3.18
2.92
0.45
%RSD
1.77
0.02
2.45
1.01
1.28
1.01
1.57
Fortified Sample Cone.
Mean
11.2
12.7
11.0
12.6
13.5
13.0
10.7
%REC
97
99
98
100
103
101
102
N = 3, samples fortified at 10 mg/L OC using KHP
415.3-45
-------
17.2 SINGLE TOC INSTRUMENT PRECISION AND ACCURACY, cont'd.
17.2.4 TOC Instrument 4: Catalyzed, 680 °C combustion oxidation/NDIR
Dissolved Organic Carbon, mg/La
Source
Water
Boulder Creek
Shingobee R.
Bolten Well
Ohio R. (F embank)
Muddy Creek
Great Miami R.
Saint Leon Well
Unfortified Sample
Cone.
Mean
1.54
2.71
1.24
2.52
3.56
3.00
0.38
%RSD
5.75
3.18
1.25
5.73
3.17
6.94
27.4
Fortified Sample Cone.
Mean
11.4
12.4
12.4
12.4
13.3
12.7
10.1
%REC
98
97
98
98
98
96
98
Total Organic Carbon, mg/La
Source
Water
Boulder Creek
Shingobee R.
Bolten Well
Ohio R. (Fernbank)
Muddy Creek
Great Miami R.
Saint Leon Well
Unfortified Sample
Cone.
Mean
1.46
2.84
1.12
2.81
4.04
3.42
0.28
%RSD
2.86
2.19
1.70
1.79
2.02
1.66
7.64
Fortified Sample Cone.
Mean
11
13
11
13
14
14
10
%REC
100
97
100
100
96
101
100
N = 3, samples fortified at 10 mg/L OC using KHP
415.3-46
-------
17.2 SINGLE TOC INSTRUMENT PRECISION AND ACCURACY, cont'd.
17.2.5 TOC Instrument 5: High temperature combustion oxidation/NDIR
Dissolved Organic Carbon, mg/La
Source
Water
Boulder Creek
Shingobee R.
Bolten Well
Ohio R. (F embank)
Muddy Creek
Great Miami R.
Saint Leon Well
Unfortified Sample
Cone.
Mean
1.21
2.29
0.90
2.11
2.89
2.43
0.38
%RSD
1.18
1.15
2.93
0.28
1.09
0.77
27.4
Fortified Sample Cone.
Mean
11.0
12.0
11.5
12.3
13.1
12.3
10.0
%REC
98
97
106
102
102
99
96
Total Organic Carbon, mg/La
Source
Water
Boulder Creek
Shingobee R.
Bolten Well
Ohio R. (Fernbank)
Muddy Creek
Great Miami R.
Saint Leon Well"
Unfortified Sample
Cone.
Mean
1.26
2.45
0.93
2.31
3,34
2.72
0.32
%RSD
6.02
0.84
1.02
1.19
3.40
0.78
N/A
Fortified Sample Cone.
Mean
11.0
12.1
10.8
12.1
13.1
12.3
10.0
%REC
97
97
98
98
98
96
97
a N = 3, samples fortified at 10 mg/L OC using KHP
b N = 2 for this sample, N/A = not applicable
415.3-47
-------
17.3 PRECISION AND ACCURACY DATA FOR DOC AND SUVA MEASURED IN
SEVEN SOURCE WATERS ON FIVE INSTRUMENTS3
17.3.1 DOC Measurements for Seven Source Waters, Three Replicate
Instrument Injections on Five Instruments
Dissolved Organic Carbon, mg/L, Unfortified Samples
Source Water
Boulder Creek
Shingobee R.
Bolton Well
Ohio R. (Fernbank)
Muddy Creek
Great Miami R.
St. Leon Well
Inst
#1
1.64
2.98
1.27
2.79
3.81
3.18
0.53
Inst
#2
1.40
2.58
1.04
2.41
3.25
2.69
0.40
Inst
#3
1.52
2.71
1.18
2.50
3.38
2.91
0.56
Inst
#4
1.54
2.71
1.24
2.52
3.56
3.00
0.38
Inst
#5
1.21
2.29
0.90
2.12
2.89
2.43
0.25
Mean
1.46
2.66
1.13
2.47
3.38
2.84
0.42
Std
Dev
0.17
0.25
0.15
0.24
0.34
0.29
0.13
%RSD
11
9
14
10
10
10
30
17.3.2 DOC Measurements for Seven Source Waters, Fortified with KHP, Three
Replicate Instrument Injections on Five Instruments
Dissolved Organic Carbon, mg/L, Samples Fortified at 10 mg/L OC
Source Water
Boulder Creek
Shingobee R.
Bolton Well
Ohio R. (Fernbank)
Muddy Creek
Great Miami R.
St. Leon Well
Inst #1
12.2
13.5
12.0
13.6
14.6
13.7
11.0
Inst #2
11.8
13.3
11.5
13.2
14.3
13.4
10.5
Inst #3
11.5
13.2
11.3
13.1
14.0
13.1
10.7
Inst #4
11.4
12.4
11.2
12.4
13.3
12.7
10.1
Inst #5
11.0
12.0
11.5
12.3
13.1
12.3
10.0
Mean
11.6
12.9
11.5
12.9
13.9
13.0
10.5
Std
Dev
0.43
0.62
0.31
0.54
0.62
0.55
0.40
%RSD
4
5
3
4
5
4
4
%RECb
101
102
104
105
105
102
100
a For instrument identification (by type) see Section 6.3.
b % Recovery calculated as described in Section 9.8.
415.3-48
-------
17.3 PRECISION AND ACCURACY DATA FOR DOC AND SUVA MEASURED IN
SEVEN SOURCE WATERS ON FIVE INSTRUMENTS3, cont'd.
17.3.3 Mean SUVA Calculation Based on the DOC Data in 17.3.1 for Seven
Source Waters
Source Water
Boulder Creek
Shingobee R.
Bolton Well
Ohio R. (Fernbank)
Muddy Creek
Great Miami R.
St. Leon Well
UVA
(cm1)
0.4324
0.7440
0.2364
0.7267
1.124
0.8948
0.0771
SUVA b (L/mg-M)
Inst #1
2.62
2.50
1.86
2.60
2.95
2.81
1.46
Inst #2
3.08
2.88
2.28
3.01
3.46
3.33
1.93
Inst #3
2.84
2.75
2.01
2.90
3.33
3.07
1.38
Inst #4
2.97
2.77
1.91
2.88
3.20
3.05
1.83
Inst #5
3.58
3.25
2.62
3.43
3.89
3.69
3.13
Mean
3.02
2.83
2.14
2.97
3.37
3.19
1.95
a For instrument identification (by type) see Section 6.3.
b SUVA calculated as described in Section 12.2.
415.3-49
-------
17.4 PRECISION AND ACCURACY DATA FOR TOC MEASURED IN SEVEN
SOURCE WATERS ON FIVE INSTRUMENTS"
17.4.1 TOC Measurements for Seven Source Waters, Three Replicate Instrument
Injections on Five Instruments
Total Organic Carbon, mg/L, Unfortified Samples
Source Water
Boulder Creek
Shingobee R.
Bolton Well
Ohio R. (Fernbank)
Muddy Creek
Great Miami R.
St. Leon Well
Inst #1
1.73
3.16
1.32
3.02
4.24
3.51
0.66
Inst #2
1.38
2.62
1.05
2.46
3.41
2.89
0.39
Inst #3
1.47
2.72
1.16
2.58
3.18
2.92
0.45
Inst #4
1.46
2.84
1.12
2.81
4.04
3.42
0.28
Inst #5
1.26
2.45
0.93
2.31
3.34
2.72
0.32
Mean
1.46
2.76
1.12
2.64
3.64
3.09
0.42
Std
Dev
0.17
0.26
0.14
0.28
0.47
0.35
0.15
%RSD
12
10
13
11
13
11
35
17.4.2 TOC Measurements for Seven Source Waters, Fortified with KHP, from
Replicate Instrument Injections on Five Instruments
Total Organic Carbon, mg/L, Samples Fortified at 10 mg/L OC
Source Water
Boulder Creek
Shingobee R.
Bolton Well
Ohio R. (Fernbank)
Muddy Creek
Great Miami R.
St. Leon Well
Inst #1
12.1
13.0
11.4
13.2
14.6
13.8
11.1
Inst #2
11.3
12.7
11.4
13.1
13.8
13.2
10.5
Inst #3
11.2
12.6
11.0
12.6
13.5
13.0
10.7
Inst #4
11.4
12.5
11.2
12.8
13.7
13.6
10.2
Inst #5
11.0
12.1
10.8
12.1
13.1
12.3
10.0
Mean
11.4
12.6
11.1
12.8
13.7
13.2
10.5
Std
Dev
0.43
0.32
0.28
0.45
0.54
0.59
0.41
%RSD
4
3
3
4
4
5
4
%RECb
99
98
100
101
101
101
101
a For instrument identification (by type) see Section 6.3.
b % Recovery calculated as described in Section 9.8.
415.3-50
-------
17.5 INITIAL DEMONSTRATION OF CAPABILITY (IDC) REQUIREMENTS
(SUMMARY)
Method
Reference
Sects. 9.2.1,
9.9
Sects. 9.2.2,
9.11
Sect. 9.2.3
Sect. 9.2.4
Sect. 9.2.5
Sect. 9.2.6
Sect. 9.2.7
Requirement
Initial
Demonstration of
Low System
Background
Initial Calibration
Verification
Initial Organic
Carbon Flow
Injection Memory
Check
Inorganic Carbon
Removal
Initial
Demonstration of
Accuracy
Initial
Demonstration of
Precision
Organic Carbon
Detection Limit
(OCDL)
Determination
Specification and
Frequency
Analyze LRB prior to
any other IDC
samples.
After initial calibration
of TOC instrument
system a QCS sample
is used to verify
accuracy.
Analyze after Low
System Background
requirement, but
before any other TOC
or DOC IDC samples.
Prior to first analysis
of samples and
whenever the 1C
removal procedure is
modified.
Analyze 5 replicate
LFBs (at 2-5 mg/L
OC).
Calculate precision of
the accuracy samples.
Analyze 7 replicate
LFBs over a period of
at least 3 days at a
concentration
estimated to be near
the DL.
Acceptance Criteria
LRBs must be < 0.35 mg/L OC
and < 0.01 crn1 UVA.
The analyzed value of a 1-5 mg/L
calibration standard must be
within ±20% of the true value
before proceeding with the
method.
LRB injections after the highest
OC-CAL injection must be
< 0.3 5 mg/L TOC.
Analysis of the IC-TEST solution
after 1C removal must result in a
concentration of < 0.35 mg/L 1C,
measured as OC interference.
The average recovery must be
+20% of the true value.
The %RSD must be < 20%.
The calculated OCDL must not
exceed 0.35 mg/L. The mean
recovery of the LFBs used in the
OCDL determination must be
+50% of the true value.
415.3-51
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Method
Reference
Sect. 9.3.2
Sect. 9.4.1
Sects. 9.4.2,
10.4
Requirement
Initial
Demonstration of
Filter Membrane
Suitability
Initial
Spectrophotometer
Check
Spectrophotometer
Performance Check
Specification and
Frequency
Prior to the first use of
filters and whenever a
manufacturer or filter
type is changed.
Prior to first
instrument use and
annually thereafter.
Prior to analysis of
samples.
Acceptance Criteria
FB < 0.35 mg/L OC and/or
<0.01 cm'1 UVA. Sample
filtrate OC within +15% of
unfiltered sample OC.
Test two wavelengths between
220 and 340 nm. Check
manufacturer' s operation manual
for acceptance limits.
UVA within 10% of expected
absorbance value.
415.3-52
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17.6 QUALITY CONTROL REQUIREMENTS (SUMMARY)
Method
Reference
Requirement
Specification and
Frequency
Acceptance Criteria
Sect. 9.9
Blanks
One LRB with each TOC
analysis batch. One FB
with each DOC and UVA
analysis batch.
TOC LRBs and DOC-FBs
must be < 0.35 mg/L OC.
The UVA-FB must be < 0.01
cm'1 UVA.
Sect. 8.1
Holding Time,
SUVA
DOC - filtered and then
acidified within 48 hours of
collection. Analyzed
within 28 days of time of
collection.
Stored at < 6 °C; preserved
with acid to pH < 2 after
filtration.
UVA - filtered and
analyzed within 48 hours of
time of collection.
Not preserved with acid,
stored at < 6 °C.
Sect. 8.2
Holding Time,
TOC
TOC - analyze within 28
days from time of
collection.
Preserved at pH < 2 at the
time of collection, stored at
<6°C.
Sects. 9.2,
9.3, 9.4
Initial
Demonstration of
Capability (IDC)
Performed whenever a new
instrument is set up or
when a new analyst is
trained.
See Table 17.5.
Sect. 9.5,
10.3
Continuing
Calibration Checks
Analysis of Low-CCC (at
the MRL or below) at the
beginning of each analysis
batch. Subsequent CCCs
analyzed after every 10
samples and after the last
sample in the analysis
batch, rotating
concentrations to cover the
calibrated range of the
instrument. Mid-CCC
required during each
analysis batch.
Low-CCC: + 50% of true
value.
Mid-CCC:+ 20% of true
value.
High-CCC:±15%oftrue
value.
415.3-53
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Method
Reference
Sect. 9.6
Sect. 9.7
Sect. 9.8
Sect. 9.11
Section
10.2
Section
10.4
Requirement
Field Duplicate
(FD) Analyses
Laboratory
Fortified Blank
(LFB) analysis
Laboratory
Fortified Matrix
(LFM)
Quality Control
Sample (QCS)
Calibration Curve
Spectrophotometer
performance check
Specification and
Frequency
One FD is collected and
analyzed with each analysis
batch.
One LFB is analyzed with
every DOC analysis batch.
One LFM is analyzed with
every TOC or DOC
analysis batch. Spike
concentration should result
in an increase in the LFM
concentration of 50 to
200% of its measured or
expected concentration.
The QCS is analyzed
during the IDC, after each
new calibration curve, each
time new calibration
solutions are prepared, or at
least quarterly.
A new calibration curve is
generated when fresh
standards are made and/or
when CCCs are out of QC
limits.
The day to day performance
of the Spectrophotometer is
checked using the COMM-
SCS and/or KHP-SCS prior
to analyzing any UVA
sample(s).
Acceptance Criteria
FD>2mg/LOC<20%
RPD. UVA<10%RPD.
Concentration of 1-5 mg/L
OC using KHP. Recovery
must be within + 20% of true
value.
Recovery outside 70-130%
warrants investigation of
matrix effect.
The analyzed value of a 1-5
mg/L QCS must be within
±20% of the true value.
Calibration curve must have
r2 > 0.993 before proceeding
with analyses.
The UVA of the KHP-SCS or
COMM-SCS reading must be
within 10% expected
absorbance values. Analysis
of LRW must result in UVA
of <0.01 cm-1.
415.3-54
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FIGURE 1: FILTER BLANK PREPARATION
LRW
WASH FILTER*,
DISCARD
FILTER LRW*,
DISPENSE INTO
40-ML VIALS
DESIGNATE AS
FILTER BLANK (FB)
DOC -FB
ADD ACID
SPARGE
ANALYZE
UVA - FB
NO ACID
NO SPARGE
ANALYZE
*Using volume as determined in Section 9.3.2.
415.3-55
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FIGURE 2 : SAMPLE PREPARATION
WATER SAMPLE
TOC
DOC
UVA
USING PRE - WASHED FILTERS
FILTER AND DISCARD FIRST PORTION*
TO WASTE
FILTER REMAINING SAMPLE
DISPENSE INTO 40ML VIALS
TOC AND DOC-SAMPLE
ADD ACID
SPARGE
ANALYZE
UVA-SAMPLE
NO ACID
NO SPARGE
ANALYZE
Using volume as determined in Section 9.3.2.3.
415.3-56
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