METHOD 300.1
DETERMINATION OF INORGANIC ANIONS IN DRINKING WATER BY ION
CHROMATOGRAPHY
Revision 1.0
John D. Pfaff (USEPA, ORD, NERL) - Method 300.0, (1993)
Daniel P. Hautman (USEPA, Office of Water) and David J. Munch (USEPA, Office of Water)
-Method 300.1, (1997)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
300.1-1
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ERRATA COVER SHEET TO U.S.EPA METHOD 300.1
April 27,1999
The following were editorial changes which have been incorporated into U.S.EPA Method 300.1. These
minor clarifications are incorporated into the body of this text as follows:
ERRATA #1 -
An additional sentence was added to Section 4.1.1 reiterating the analyst's responsibilities when
incorporating any method change, including modifying eluent strength, or any other method parameter.
The additional sentence states,
"... The analyst must verify that these changes do not negatively affect performance by repeating
and passing all the QC criteria in Section 9."
On this same theme, section 11.9, was also further clarified and specific precautions were added as
follows,
" ...The analysts must verify that this dilution does not negatively affect performance by repeating
and passing all the QC criteria in Section 9. As a specific precaution, upon dilution of the
carbonate eluent, apeak for bicarbonate may be observed within the retention time window for
br-ornate which will negatively impact the analysis."
ERRATA #2 -
An acronym in Section 9.3.2.2 for Laboratory Fortified Blank (LFB) was incorrectly identified as LRB.
This typographical error was corrected.
ERRATA #3 -
Clarifications and corrections were made to Section 9.4.1.5, 9.4.3.2 and 9.4.3.3. These clarifications
pertain to data reportability for Laboratory Fortified Sample Matrices (LFM) as well as to analysis
continuation when Duplicate Sample QC acceptance criteria are not met.
Section 9.4.1.5 clarifies and now specifies how to report data when the LFM recovery falls outside the
established control criteria by stating,
"...the recovery problem encountered with the LFM is judged to be matrix induced and the results
for that sample and the LFM are reported with a "matrix induced bias " qualifier."
Section 9.4.3.2 required the correction of a typographical reference by removing "%Diff" in the duplicate
sample acceptance criteria and replacing it with the defined RPD, indicating "relative percent difference".
Section 9.4.3.3, also had a "%Diff" reference corrected with RPD and included clarification regarding
continuation of an analysis set when a duplicate analysis fails to meet the acceptance criteria. This section
now reads,
"If the RPD fails to meet these criteria, the samples must be reported with a qualifier identifying
the sample analysis result as yielding a poor duplicate analysis RPD. This should not be a
chronic problem and if it frequently recurs, (>20% of duplicate analysis) it indicates a problem
with the instrument or individual technique."
ERRATA COVER SHEET
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METHOD 300.1
DETERMINATION OF INORGANIC ANIONS IN DRINKING WATER
BY ION CHROMATOGRAPHY
1. SCOPE AND APPLICATION
1.1 This method covers the determination of the following inorganic anions in reagent
water, surface water, ground water, and finished drinking water. As a result of
different specified injection volumes (See conditions in Tables 1A and IB), these
anions are divided between the common anions listed in Part A and the inorganic
disinfection by-products listed in Part B. These different injection volumes are
required in order to compensate for the relative concentrations of these anions in
drinking water and maintain good chromatographic peak shape throughout the
expected dynamic range of the detector. Bromide is included in both Part A, due
to its importance as a common anion, as well as Part B due to its critical role as a
disinfection by-product precursor.
PART A.— Common Anions
Bromide Nitrite
Chloride ortho-Phosphate-P
Fluoride Sulfate
Nitrate
PART B.— Inorganic Disinfection By-products
Bromate Chlorite
Bromide Chlorate
1.2 The single laboratory Method Detection Limits (MDL, defined in Sect. 3.11) for
the above analytes are listed in Tables 1 A, IB and 1C. The MDL for a specific
matrix may differ from those listed, depending upon the nature of the sample and
the specific instrumentation employed.
1.2.1 In order to achieve comparable detection limits, an ion chromatographic
system must utilize suppressed conductivity detection, be properly
maintained and must be capable of yielding a baseline with no more than
5 nS noise/drift per minute of monitored response over the background
conductivity.
1.3 This method is recommended for use only by or under the supervision of analysts
experienced in the use of ion chromatography and in the interpretation of the
resulting ion chromatograms.
1.4 When this method is used to analyze unfamiliar samples for any of the above
anions, anion identification should be supported by the use of a fortified sample
matrix covering the anions of interest. The fortification procedure is described in
Sect. 9.4.1.
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1.5 Users of the method data should state the data-quality objectives prior to analysis.
Users of the method must demonstrate the ability to generate acceptable results
with this method, using the procedures described in Sect. 9.0.
1.6 Bromide and nitrite react with most oxidants employed as disinfectants. The
utility of measuring these anions in treated water should be considered prior to
conducting the analysis.
2. SUMMARY OF METHOD
2.1 A small volume of sample, 10 uL for Part A and 50 uL for Part B, is introduced
into an ion chromatograph. The anions of interest are separated and measured,
using a system comprised of a guard column, analytical column, suppressor
device, and conductivity detector.
2.2 The ONLY difference between Parts A and B is the volume of sample analyzed
by the ion chromatographic system. The separator columns and guard columns as
well as eluent conditions are identical.
3. DEFINITIONS
3.1 ANALYSIS BATCH -- A group of no more than 20 field samples (Field sample
analyses include only those samples derived from a field sample matrix. These
include the initial and duplicate field samples as well as all Laboratory Fortified
Sample Matrices). The analysis batch must include an Initial Calibration Check
Standard, an End Calibration Check Standard, Laboratory Reagent Blank, and a
Laboratory Fortified Blank. Within an ANALYSIS BATCH, for every group of
ten field samples, at least one Laboratory Fortified Matrix (LFM) and either a
Field Duplicate, a Laboratory Duplicate or a duplicate of the LFM must be
analyzed. When more than 10 field samples are analyzed, a Continuing
Calibration Check Standard must be analyzed after the tenth field sample analysis.
3.2 CALIBRATION STANDARD (CAL) - A solution prepared from the primary
dilution standard solution or stock standard solutions and the surrogate analyte.
The CAL solutions are used to calibrate the instrument response with respect to
analyte concentration.
3.2.1 INITIAL CALIBRATION STANDARDS -- A series of CAL solutions
used to initially establish instrument calibration and develop calibration
curves for individual target anions.
3.2.2 INITIAL CALIBRATION CHECK STANDARD -- An individual CAL
solution, analyzed initially, prior to any sample analysis, which verifies
previously established calibration curves.
3.2.3 CONTINUING CALIBRATION CHECK STANDARD - An individual
CAL solution which is analyzed after every tenth field sample analyses
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which verifies the previously established calibration curves and confirms
accurate analyte quantitation for the previous ten field samples analyzed.
3.2.4 END CALIBRATION CHECK STANDARD - An individual CAL
solution which is analyzed after the last field sample analyses which
verifies the previously established calibration curves and confirms
accurate analyte quantitation for all field samples analyzed since the last
continuing calibration check.
3.3 FIELD DUPLICATES — 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 field duplicates indicate the precision
associated with sample collection, preservation and storage, as well as with
laboratory procedures.
3.4 INSTRUMENT PERFORMANCE CHECK SOLUTION (IPC) - A solution of
one or more method analytes, surrogates, or other test substances used to
evaluate the performance of the instrument system with respect to a defined set of
criteria.
3.5 LABORATORY DUPLICATE-- Two sample aliquots, taken in the laboratory
from a single sample bottle, and analyzed separately with identical procedures.
Analyses of LD1 and LD2 indicate precision associated specifically with the
laboratory procedures, removing any associated variables attributed by sample
collection, preservation, or storage procedures.
3.6 LABORATORY FORTIFIED BLANK (LFB) - An aliquot of reagent water or
other blank matrices to which known quantities of the method analytes are added
in the laboratory. The LFB is analyzed exactly like a sample, and its purpose is to
determine whether the methodology is in control, and whether the laboratory is
capable of making accurate and precise measurements.
3.7 LABORATORY FORTIFIED SAMPLE MATRIX (LFM) -- An aliquot of an
environmental sample to which known quantities of the method analytes are added
in the laboratory. The LFM is analyzed exactly like a sample, and its purpose is to
determine whether the sample matrix contributes bias to the analytical results. The
background concentrations of the analytes in the sample matrix must be
determined in a separate aliquot and the measured values in the LFM corrected for
background concentrations.
3.8 LABORATORY REAGENT BLANK (LRB) -- An aliquot of reagent water or
other blank matrices that are treated exactly as a sample including exposure to all
glassware, equipment, solvents, reagents, and surrogates that are used with other
samples. The LRB is used to determine if method analytes or other interferences
are present in the laboratory environment, the reagents, or the apparatus.
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3.9 LINEAR CALIBRATION RANGE (LCR) - The concentration range over which
the instrument response is linear.
3.10 MATERIAL SAFETY DATA SHEET (MSDS) -- Written information provided
by vendors concerning a chemical's toxicity, health hazards, physical properties,
fire, and reactivity data including storage, spill, and handling precautions.
3.11 METHOD DETECTION LIMIT (MDL) -- The minimum concentration of an
analyte that can be identified, measured and reported with 99% confidence that the
analyte concentration is greater than zero.
3.12 MINIMUM REPORTING LEVEL (MRL) -- The minimum concentration that
can be reported for an anion in a sample following analysis. This defined
concentration can be no lower than the concentration of the lowest calibration
standard and can only be used if acceptable quality control criteria for this standard
are met.
3.13 PERFORMANCE EVALUATION SAMPLE (PE) - A certified solution of
method analytes whose concentration is unknown to the analyst. Often, an aliquot
of this solution is added to a known volume of reagent water and analyzed with
procedures used for samples. Results of analyses are used to determine
statistically the accuracy and precision that can be expected when a method is
performed by a competent analyst.
3.14 QUALITY CONTROL SAMPLE (QCS) - A solution of method analytes of
known concentrations that is used to fortify an aliquot of LRB or sample matrix.
The QCS is obtained from a source external to the laboratory and different from
the source of calibration standards. It is used to check laboratory performance
with externally prepared test materials.
3.15 SURROGATE ANALYTE - An analyte added to a sample, which is unlikely to
be found in any sample at significant concentration, and which is added directly to
a sample aliquot in known amounts before any sample processing procedures are
conducted. It is measured with the same procedures used to measure other sample
components. The purpose of the surrogate analyte is to monitor method
performance with each sample.
3.16 STOCK STANDARD SOLUTION (SSS) -- A concentrated solution containing
one or more method analytes prepared in the laboratory using assayed reference
materials or purchased from a reputable commercial source.
4. INTERFERENCES
4.1 Interferences can be divided into three different categories: direct
chromatographic coelution, where an analyte response is observed at very nearly
the same retention time as the target anion; concentration dependant coelution,
which is observed when the response of higher than typical concentrations of the
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neighboring peak overlap into the retention window of the target anion; and, ionic
character displacement, where retention times may significantly shift due to the
influence of high ionic strength matrices (high mineral content or hardness)
overloading the exchange sites in the column and significantly shortening target
analyte's retention times.
4.1.1 A direct chromatographic coelution may be solved by changing columns,
eluent strength, modifying the eluent with organic solvents (if compatible
with 1C columns), changing the detection systems, or selective removal of
the interference with pretreatment. Sample dilution will have little to no
effect. The analyst must verify that these changes do not negatively affect
performance by repeating and passing all the QC criteria in Section 9.
4.1.2 Sample dilution may resolve some of the difficulties if the interference is
the result of either concentration dependant coelution or ionic character
displacement, but it must be clarified that sample dilution will alter your
Minimum Reporting Limit (MRL) by a proportion equivalent to that of
the dilution. Therefore, careful consideration of project objectives should
be given prior to performing such a dilution. An alternative to sample
dilution, may be dilution of the eluent as outlined in 11.9.
4.1.3 Pretreatment cartridges can be effective as a means to eliminate certain
matrix interferences. Prior to using any pretreatment, the analyst should
be aware that all instrument calibration standards must be pretreated in
exactly the same manner as the pretreated unknown field samples. The
need for these cartridges have been greatly reduced with recent advances
in high capacity anion exchange columns.
4.1.3.1 Extreme caution should be exercised in using these
pretreatment cartridges. Artifacts are known to leach from
certain cartridges which can foul the guard and analytical
columns causing loss of column capacity indicated by
shortened retention times and irreproducible results.
Frequently compare your calibration standard chromatograms
to those of the column test chromatogram (received when the
column was purchased) to insure proper separation and similar
response ratios between the target analytes is observed.
4.2 Method interferences may be caused by contaminants in the reagent water,
reagents, glassware, and other sample processing apparatus that lead to discrete
artifacts or elevated baselines in an ion chromatogram. These interferences can
lead to false positive results for target analytes as well as reduced detection limits
as a consequence of elevated baseline noise.
4.3 Samples that contain particles larger than 0.45 microns and reagent solutions that
contain particles larger than 0.20 microns require filtration to prevent damage to
instrument columns and flow systems.
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4.4 Any anion that is only weakly retained by the column may elute in the retention
time window of fluoride and potentially interfere. At concentrations of fluoride
above 1.5 mg/L, this interference may not be significant, however, it is the
responsibility of the user to generate precision and accuracy information in each
sample matrix.
4.5 Close attention should be given to the potential for carry over peaks from one
analysis which will effect the proper detection of analytes of interest in a second,
subsequent analysis. Normally, the elution of sulfate (retention time of 13.8 min.)
indicates the end of a chromatographic run, but, in the ozonated and chlorine
dioxide matrices, which were included as part of the single operator accuracy and
bias study (See Table 2B), a small response (200 nS baseline rise) was observed
for a very late eluting unknown peak at approximately 23 minutes. Consequently,
a run time of 25 minutes is recommended to allow for the proper elution of any
potentially interferant late peaks. It is the responsibility of the user to confirm
that no late eluting peaks have carried over into a subsequent analysis thereby
compromising the integrity of the analytical results.
4.6 Any residual chlorine dioxide present in the sample will result in the formation of
additional chlorite prior to analysis. If any concentration of chlorine dioxide is
suspected in the sample, the sample must be purged with an inert gas (helium,
argon or nitrogen) for approximately five minutes or until no chlorine dioxide
remains. This sparging must be conducted prior to ethylenediamine preservation
and at time of sample collection.
5. SAFETY
5.1 The toxicity or carcinogenicity of each reagent used in this method have not been
fully established. Each chemical should be regarded as a potential health hazard
and exposure should be as low as reasonably achievable. Cautions are included
for known extremely hazardous materials or procedures.
5.2 Each laboratory is responsible for maintaining a current awareness file of OSHA
regulations regarding the safe handling of the chemicals specified in this method.
A reference file of Material Safety Data Sheets (MSDS) should be made available
to all personnel involved in the chemical analysis. The preparation of a formal
safety plan is also advisable.
5.3 The following chemicals have the potential to be highly toxic or hazardous,
consult MSDS.
5.3.1 Sulfuric acid - When used to prepared a 25 mN sulfuric acid regenerant
solution for chemical suppression using a Dionex Anion Micro Membrane
Suppressor (AMMS).
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6. EQUIPMENT AND SUPPLIES
6.1 Ion chromatograph — Analytical system complete with ion chromatograph and all
required accessories including syringes, analytical columns, compressed gasses
and a conductivity detector.
6.1.1 Anion guard column: Dionex AG9-HC, 2 mm (P/N 52248), or
equivalent. This column functions as a protector of the separator column.
If omitted from the system the retention times will be shorter.
6.1.2 Anion separator column: Dionex AS9-HC column, 2 mm (P/N 52244),
or equivalent. The microbore (2 mm) was selected in the development of
this method as a means to tighten the bromate elution band and thus
reduce the detection limit. An optional column (2 mm or 4 mm) may be
used if comparable resolution of peaks is obtained, and the requirements
of Sect. 9.0 can be met. The AS9-HC, 2 mm column using the conditions
outlined in Table 1A and IB produced the separation shown in Figures 1
through 4.
6.1.2.1 If a 4 mm column is employed, the injection volume should be
raised by a factor of four to 40 uL for Part A anions and 200
uL for Part B anions in order to attain comparable detection
limits. A four fold increase in injection volume compensates
for the four fold increase in cross sectional surface area of the
4 mm standard bore column over the 2 mm microbore column.
6.1.2.2 Comparable results can be attained using the Dionex, AS9-HC,
4 mm column. MDLs for the part B, inorganic disinfection by-
products using this 4 mm column are displayed along with
analysis conditions in Table 1C.
6.1.3 Anion suppressor device: The data presented in this method were
generated using a Dionex Anion Self Regenerating Suppressor (ASRS,
P/N 43187). An equivalent suppressor device may be utilized provided
comparable detection limits are achieved and adequate baseline stability is
attained as measured by a combined baseline drift/noise of no more than 5
nS per minute over the background conductivity.
6.1.3.1 The ASRS was set to perform electrolytic suppression at a
current setting of 100 mA using an external source DI water
mode. Insufficient baseline stability was observed using the
ASRS in recycle mode.
6.1.4 Detector — Conductivity cell (Dionex CD20, or equivalent) capable of
providing data as required in Sect. 9.2.
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6.2 The Dionex Peaknet Data Chromatography Software was used to generate all the
data in the attached tables. Systems using a strip chart recorder and integrator or
other computer based data system may achieve approximately the same MDL's
but the user should demonstrate this by the procedure outlined in Sect. 9.2.
6.3 Analytical balance, ±0.1 mg sensitivity. Used to accurately weigh target analyte
salts for stock standard preparation.
6.4 Top loading balance, ±10 mg sensitivity. Used to accurately weigh reagents to
prepare eluents.
6.5 Weigh boats, plastic, disposable - for weighing eluent reagents.
6.6 Syringes, plastic, disposable, 10 mL - used during sample preparation.
6.7 Pipets, Pasteur, plastic or glass, disposable, graduated, 5 mL and 10 mL.
6.8 Bottles, high density polyethylene (HDPE), opaque or glass, amber, 30 mL, 125
mL, 250 mL. For sampling and storage of calibration solutions. Opaque or
amber due to the photoreactivity of chlorite anion.
6.9 Micro beakers, plastic, disposable - used during sample preparation.
7. REAGENTS AND STANDARDS
7.1 Reagent water: Distilled or deionized water, free of the anions of interest. Water
should contain particles no larger than 0.20 microns.
7.2 Eluent solution : Sodium carbonate (CASRN 497-19-8) 9.0 mM. Dissolve 1.91
g sodium carbonate (Na2CO3) in reagent water and dilute to 2 L.
7.2.1 This eluent solution must be purged for 10 minutes with helium prior to
use to remove dissolved gases which may form micro bubbles in the 1C
compromising system performance and adversely effecting the integrity of
the data.
7.3 Stock standard solutions, 1000 mg/L (1 mg/mL): Stock standard solutions may
be purchased as certified solutions or prepared from ACS reagent grade,
potassium or sodium salts as listed below, for most analytes. Chlorite requires
careful consideration as outline below in 7.3.5.1.
7.3.1 Bromide (Bf) 1000 mg/L: Dissolve 0.1288 g sodium bromide (NaBr,
CASRN 7647-15-6) in reagent water and dilute to 100 mL in a
volumetric flask.
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7.3.2 Bromate (BrO3") 1000 mg/L: Dissolve 0.1180 g of sodium bromate
(NaBrO3, CASRN 7789-38-0) in reagent water and dilute to 100 mL in a
volumetric flask.
7.3.3 Chlorate (C1(V) 1000 mg/L: Dissolve 0.1275 g of sodium chlorate
(NaC103, CASRN 7775-09-9) in reagent water and dilute to 100 mL in a
volumetric flask.
7.3.4 Chloride (Cl') 1000 mg/L: Dissolve 0.1649 g sodium chloride (NaCl,
CASRN 7647-14-5) in reagent water and dilute to 100 mL in a
volumetric flask.
7.3.5 Chlorite (C102~) 1000 mg/L: Assuming an exact 80.0 % NaC102 is
amperometrically titrated from technical grade NaC102(See Sect.
7.3.5.1). Dissolve 0.1676 g of sodium chlorite (NaC102, CASRN 7758-
19-2) in reagent water and dilute to 100 mL in a volumetric flask.
7.3.5.1 High purity sodium chlorite (NaCIO2) is not currently
commercially available due to potential explosive instability.
Recrystallization of the technical grade (approx. 80%) can be
performed but it is labor intensive and time consuming. The
simplest approach is to determine the exact % NaCIO 2 using
the iodometric titration procedure (Standard Methods, 19th
Ed., 4500-C1O2.C). Following titration, an individual
component standard of chlorite must be analyzed to determine
if there is any significant contamination (greater than 1% of the
chlorite weight) in the technical grade chlorite standard from
any of the Part B components. These contaminants will place
a high bias on the calibration of the other anions if all four Part
B components are mixed in an combined calibration solution.
If these other anions are present as contaminants, a separate
chlorite calibration needs to be performed.
7.3.6 Fluoride (F) 1000 mg/L: Dissolve 0.2210 g sodium fluoride (NaF,
CASRN 7681-49-4) in reagent water and dilute to 100 mL in a
volumetric flask.
7.3.7 Nitrate (NO>N) 1000 mg/L: Dissolve 0.6068 g sodium nitrate (NaNO3,
CASRN 7631-99-4) in reagent water and dilute to 100 mL in a
volumetric flask.
7.3.8 Nitrite (NO>N) 1000 mg/L: Dissolve 0.4926 g sodium nitrite (NaNO2,
CASRN 7632-00-0) in reagent water and dilute to 100 mL in a
volumetric flask.
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7.3.9 Phosphate (PO43'-P) 1000 mg/L: Dissolve 0.4394 g potassium
dihydrogenphosphate (KH2PO4, CASRN 7778-77-0) in reagent water
and dilute to 100 mL in a volumetric flask.
7.3.10 Sulfate (SO42') 1000 mg/L: Dissolve 0.1814 g potassium sulfate (K2SO4,
CASRN 7778-80-5) in reagent water and dilute to 100 mL in a
volumetric flask.
NOTE: Stability of standards: Stock standards (7.3) for most anions are
stable for at least 6 months when stored at 4°C. Except for the
chlorite standard which is only stable for two weeks when stored
protected from light at 4°C, and nitrite and phosphate which are only
stable for 1 month when stored at 4°C. Dilute working standards
should be prepared monthly, except those that contain chlorite, or
nitrite and phosphate which should be prepared fresh daily.
7.4 Ethylenediamine (EDA) preservation solution, 100 mg/mL: Dilute 2.8 mL of
ethylenediamine (99%) (CASRN 107-15-3) to 25 mL with reagent water.
Prepare fresh monthly.
7.5 Surrogate Solution: 0.50 mg/mL dichloroacetate (DCA) prepared by dissolving
0.065 g dichloroacetic acid, potassium salt (C12CHCO2K, CASRN 19559-59-2) in
reagent water and dilute to 100 mL in a volumetric flask.
7.5.1 Dichloroacetate is potentially present in treated drinking waters as the
acetate of the organic disinfection by product, dichloroacetic acid
(DCAA). Typical concentrations of DCAA rarely exceed 50 ug/L,
which, for this worst case example, would represent only a five percent
increase in the observed response over the fortified concentration of 1.00
mg/L. Consequently, the criteria for acceptable recovery (90% to 115%)
for the surrogate is weighted to 115% to allow for this potential
background.
7.5.2 Prepare this solution fresh every 3 months or sooner if signs of
degradation are present.
8. SAMPLE COLLECTION. PRESERVATION AND STORAGE
8.1 Samples should be collected in plastic or glass bottles. All bottles must be
thoroughly cleaned and rinsed with reagent water. Volume collected should be
sufficient to insure a representative sample, allow for replicate analysis, if
required, and minimize waste disposal.
8.2 Special sampling requirements and precautions for chlorite.
8.2.1 Sample bottles used for chlorite analysis must be opaque to protect the
sample from light.
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8.2.2 When preparing the LFM, be aware that chlorite is an oxidant and may
react with the natural organic matter in an untreated drinking water
matrix as a result of oxidative demand. If untreated water is collected for
chlorite analysis, and subsequently used for the LFM, EDA preservation
will not control this demand and reduced chlorite recoveries may be
observed.
.3 Sample preservation and holding times for the anions that can be determined by
this method are as follows:
PART A : Common Anions
Analyte
Bromide
Chloride
Fluoride
Nitrate-N
Nitrite-N
ortho-Phosphate-P
Sulfate
PART B : Inorganic
Analyte
Bromate
Bromide
Chlorate
Chlorite
Preservation
None required
None required
None required
Cool to 4°C
Cool to 4°C
Cool to 4°C
Cool to 4°C
Disinfection Bv-products
Preservation
50 mg/L EDA
None required
50 mg/L EDA
50 mg/L EDA, Cool to 4°C
Holding Time
28 days
28 days
28 days
48 hours
48 hours
48 hours
28 days
Holding Time
28 days
28 days
28 days
14 days
8.4 When collecting a sample from a treatment plant employing chlorine dioxide, the
sample must be sparged with an inert gas (helium, argon, nitrogen) prior to
addition of the EDA preservative at time of sample collection.
8.5 All four anions, in Part B, can be analyzed in a sample matrix which has been
preserved with EDA. Add a sufficient volume of the EDA preservation solution
(Sect. 7.4) such that the final concentration is 50 mg/L in the sample. This would
be equivalent to adding 0.5 mL of the EDA preservation solution to 1 L of
sample.
8.6 EDA is primarily used as a preservative for chlorite. Chlorite is susceptible to
degradation both through catalytic reactions with dissolved iron salts and
reactivity towards free chlorine which exists as hypochlorous acid/hypochlorite
ion in most drinking water as a residual disinfectant. EDA serves a dual purpose
as a preservative for chlorite by chelating iron as well as any other catalytically
destructive metal cations and removing hypochlorous acid/hypochlorite ion by
forming an organochloroamine. EDA preservation of chlorite also preserves the
integrity of chlorate which can increase in unpreserved samples as a result of
chlorite degradation. EDA also preserves the integrity of bromate concentrations
by binding with hypobromous acid/hypobromite which is an intermediate formed
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as by-product of the reaction of either ozone or hypochlorous acid/hypochlorite
with bromide ion. If hypobromous acid/hypobromite is not removed from the
matrix further reactions may form bromate ion.
8.7 Degradation of ortho-phosphate has been observed in samples held at room
temperature for over 16 hrs (see table 3 A). Therefore, samples to be analyzed for
ortho-phosphate must not be held at room temperature for more than 12
cumulative hours.
9. QUALITY CONTROL
9.1 Each laboratory using this method is required to operate a formal quality control
(QC) program. The requirements of this program consist of an initial
demonstration of laboratory performance, and subsequent analysis in each
analysis batch (Sect. 3.1) of a Laboratory Reagent Blank, Laboratory Fortified
Blank, Instrument Performance Check Standard, calibration check standards,
Laboratory Fortified Sample Matrices (LFM) and either Field, Laboratory or
LFM duplicate sample analyses. This section details the specific requirements for
each of these QC parameters. The laboratory is required to maintain performance
records that define the quality of the data that are generated.
9.2 INITIAL DEMONSTRATION OF PERFORMANCE
9.2.1 The initial demonstration of performance is used to characterize
instrument performance (determination of accuracy through the analysis
of the QCS) and laboratory performance (determination of MDLs) prior
to performing analyses by this method.
9.2.2 Quality Control Sample (QCS) - When beginning the use of this method,
on a quarterly basis or as required to meet data-quality needs, verify the
calibration standards and acceptable instrument performance with the
preparation and analyses of a QCS. If the determined concentrations are
not within ± 15% of the stated values, performance of the determinative
step of the method is unacceptable. The source of the problem must be
identified and corrected before either proceeding with the initial
determination of MDLs or continuing with on-going analyses.
9.2.3 Method Detection Limit (MDL) - MDLs must be established for all
analytes, using reagent water (blank) fortified at a concentration of three
to five times the estimated instrument detection limit.(6) To determine
MDL values, take seven replicate aliquots of the fortified reagent water
and process through the entire analytical method over at least three
separate days. Perform all calculations defined in the method and report
the concentration values in the appropriate units. Calculate the MDL as
follows:
MDL = (t) x (S)
300.1-13
-------
where, t = Student's t value for a 99% confidence level and a
standard deviation estimate with n-1 degrees of freedom
[t = 3.14 for seven replicates].
S = standard deviation of the replicate analyses.
9.2.3.1 MDLs should be determined every 6 months, when a new
operator begins work or whenever there is a significant change
in the background, or instrument response.
9.3 ASSESSING LABORATORY PERFORMANCE
9.3.1 Laboratory Reagent Blank (LRB) — The laboratory must analyze at least
one LRB with each analysis batch (defined Sect 3.1). Data produced are
used to assess contamination from the laboratory environment. Values
that exceed the MDL indicate laboratory or reagent contamination should
be suspected and corrective actions must be taken before continuing the
analysis.
9.3.1.1 If conducting analysis for the Part B anions, EDA must be
added to the LRB at 50 mg/L. By including EDA in the LRB,
any bias as a consequence of the EDA which may be observed
in the field samples, particularly in terms of background
contamination, will be identified.
9.3.2 Laboratory Fortified Blank (LFB) — The LFB should be prepared at
concentrations similar to those expected in the field samples and ideally at
the same concentration used to prepare the LFM. Calculate accuracy as
percent recovery (Sect. 9.4.1.3). If the recovery of any analyte falls
outside the required concentration dependant control limits (Sect.
9.3.2.2), that analyte is judged out of control, and the source of the
problem should be identified and resolved before continuing analyses.
9.3.2.1 If conducting analysis for the Part B anions, EDA must be
added to the LFB at 50 mg/L. The addition of EDA to all
reagent water prepared calibration and quality control samples
is required not as a preservative but rather as a means to
normalize any bias attributed by the presence of EDA in the
field samples.
9.3.2.2 Control Limits for the LFB
Concentration range Percent Recovery Limits
MRL to lOxMRL 75-125 %
1 OxMRL to highest calibration level 85 - 115 %
300.1-14
-------
9.3.2.2. 1 These control limits only apply if the MRL is established within
a factor of 10 times the MDL. Otherwise, the limits are set at
85% to 115%.
9.3.2.3 The laboratory must use the LFB to assess laboratory perfor-
mance against the required control limits listed in 9.3.2.2.
When sufficient internal performance data become available
(usually a minimum of 20-30 analyses), optional control limits
can be developed from the percent mean recovery (x) and the
standard deviation (S) of the mean recovery. These data can
be used to establish the upper and lower control limits as
follows:
UPPER CONTROL LIMIT = x + 3S
LOWER CONTROL LIMIT = x - 3S
The optional control limits must be equal to or better than
those listed in 9.3.2.2. After each five to ten new recovery
measurements, new control limits can be calculated using only
the most recent 20-30 data points. Also, the standard
deviation (S) data should be used to establish an on-going
precision statement for the level of concentrations monitored.
These data must be kept on file and be available for review.
9.3.3 Instrument Performance Check Solution (TPC) — The Initial Calibration
Check Standard is to be evaluated as the instrument performance check
solution in order to confirm proper instrument performance. Proper
chromatographic performance must be demonstrated by calculating the
Peak Gaussian Factor (PGF), which is a means to measure peak
symmetry and monitoring retention time drift in the surrogate peak over
time. Critically evaluate the surrogate peak in the initial calibration check
standard, and calculate the PGF as follows,
1.83 x W(l/2)
PGF = -----------------------
where: W(l/2) is the peak width at half height
W(l/10) is the peak width at tenth height
9.3.3.1 The PGF must fall between 0.80 and 1.15 in order to
demonstrate proper instrument performance.
9.3.3.2 The retention time for the surrogate in the IPC must be closely
monitored on each day of analysis and throughout the lifetime of
the analytical column. Small variations in retention time can be
anticipated when a new solution of eluent is prepared but if
shifts of more than 2% are observed in the surrogate retention
time, some type of instrument problem is present. Potential
300.1-15
-------
problems include improperly prepared eluent, erroneous method
parameters programmed such as flow rate or some other system
problem. The chromatographic profile (elution order) of the
target anions following an ion chromatographic analysis should
closely replicate the profile displayed in the test chromatogram
that was shipped when the column was purchased. As a column
ages, it is normal to see a gradual shift and shortening of
retention times, but if after several years of use, extensive use
over less than a year, or use with harsh samples, this retention
time has noticeably shifted to any less than 80% of the original
recorded value, the column may require cleaning or
replacement. Particularly if resolution problems are beginning
to become common between previously resolved peaks. A
laboratory must retain a historic record of retention times for
the surrogate and all the target anions to provide evidence of an
analytical columns vitality.
9.4 ASSESSING ANALYTE RECOVERY AND DATA QUALITY
9.4.1 Laboratory Fortified Sample Matrix (LFM) — The laboratory must add a
known amount of analyte to a minimum of 10% of the field samples
within an analysis batch. The LFM sample must be prepared from a
sample matrix which has been analyzed prior to fortification. The analyte
concentration must be high enough to be detected above the original
sample and should adhere to the requirement of 9.4.1.2. It is
recommended that the solutions used to fortify the LFM be prepared
from the same stocks used to prepare the calibration standards and not
from external source stocks. This will remove the bias contributed by an
externally prepared stock and focus on any potential bias introduced by
the field sample matrix.
9.4.1.1 If the fortified concentration is less than the observed
background concentration of the unfortified matrix, the
recovery should not be calculated. This is due to the difficulty
in calculating accurate recoveries of the fortified concentration
when the native sample concentration is so high.
9.4.1.2 The LFM should be prepared at concentrations no greater than
five times the highest concentration observed in any field
sample. If no analyte is observed in any field sample, the LFM
must be fortified no greater than five times the lowest
calibration level which as outlined in 12.2 is the minimum
reported level (MRL). For example, if bromate is not detected
in any field samples above the lowest calibrations standard
concentration of 5.00 ug/L, the highest LFM fortified
concentration allowed is 25.0 ug/L.
300.1-16
-------
9.4.1.3 Calculate the percent recovery for each analyte, corrected for
concentrations measured in the unfortified sample. Percent
recovery should be calculated using the following equation:
CS-C
R= x 100
where, R = percent recovery.
Cs = fortified sample concentration
C = sample background concentration
s = concentration equivalent of analyte added to
sample.
9.4.1.4 Until sufficient data becomes available (usually a minimum of 20
to 30 analysis), assess laboratory performance against recovery
limits of 75 to 125%. When sufficient internal performance data
becomes available develop control limits from percent mean
recovery and the standard deviation of the mean recovery. The
optional control limits must be equal to or better than the
required control limits of 75-125%.
9.4. 1.5 If the recovery of any analyte falls outside the designated LFM
recovery range and the laboratory performance for that analyte
is shown to be in control (Sect. 9.3), the recovery problem
encountered with the LFM is judged to be matrix induced and
the results for that sample and the LFM are reported with a
"matrix induced bias" qualifier.
9.4.2 SURROGATE RECOVERY - Calculate the surrogate recovery from all
analyses using the following formula
R = --.- x 100
SFC
where, R = percent recovery.
SRC = Surrogate Recovered Concentration
SFC = Surrogate Fortified Concentration
9.4.2. 1 Surrogate recoveries must fall between 90-1 15% for proper
instrument performance and analyst technique to be verified. The
recovery of the surrogate is slightly bias to 115% to allow for the
potential contribution of trace levels of dichloroacetate as the
halogenated organic disinfection by-product (DBF) dichloroacetic
acid (DCAA) Background levels of this organic DBF are rarely
observed above 50 ug/L (0.05 mg/L) which constitutes only 5%
of the 1.00 mg/L recommended fortified concentration.
9.4.2.2 If the surrogate recovery falls outside the 90-1 15% recovery
window, a analysis error is evident and sample reanalysis is
300.1-17
-------
required. Poor recoveries could be the result of imprecise sample
injection or analyst fortification errors.
9.4.3 FIELD OR LABORATORY DUPLICATES -- The laboratory must
analyze either a field or a laboratory duplicate for a minimum of 10% of the
collected field samples or at least one with every analysis batch, whichever
is greater. The sample matrix selected for this duplicate analysis must
contain measurable concentrations of the target anions in order to establish
the precision of the analysis set and insure the quality of the data. If none
of the samples within an analysis batch have measurable concentrations, the
LFM should be employed as a laboratory duplicate.
9.4.3.1 Calculate the relative percent difference (RPD) of the initial
quantitated concentration (Ic) and duplicate quantitated
concentration (Dc) using the following formula,
(ic-Dc)
RPD = X 100
(Pc + DJ/2)
9.4.3.2 Duplicate analysis acceptance criteria
Concentration range RPD Limits
MRL to 1 OxMRL +/- 20 %
lOxMRL to highest calibration level +/- 10 %
9.4.3.3 If the RPD fails to meet these criteria, the samples must be
reported with a qualifier identifying the sample analysis result as
yielding a poor duplicate analysis RPD. This should not be a
chronic problem and if it frequently recurs (>20% of duplicate
analyses) it indicates a problem with the instrument or individual
technique.
9.4.4 Where reference materials are available, they should be analyzed to provide
additional performance data. The analysis of reference samples is a
valuable tool for demonstrating the ability to perform the method
acceptably.
9.4.5 In recognition of the rapid advances occurring in chromatography, the
analyst is permitted certain options, such as the use of different columns,
injection volumes, and/or eluents, to improve the separations or lower the
cost of measurements. Each time such modifications to the method are
made, the analyst is required to repeat the procedure in Sect. 9.2 and
adhere to the condition of baseline stability found in Sect. 1.2.1.
9.4.6 It is recommended that the laboratory adopt additional quality assurance
practices for use with this method. The specific practices that are most
300.1-18
-------
productive depend upon the needs of the laboratory and the nature of the
samples. Whenever possible, the laboratory should perform analysis of
quality control check samples and participate in relevant performance
evaluation sample studies.
10. CALIBRATION AND STANDARDIZATION
10.1 Establish ion chromatographic operating parameters equivalent to those indicated
in Tables 1A or IB if employing a 2 mm column, Table 1C if employing a 4 mm
column.
10.2 Estimate the Linear Calibration Range (LCR) — The LCR should cover the
expected concentration range of the field samples and should not extend over
more than 2 orders of magnitude in concentration (For example, if quantitating
nitrate in the expected range of 1.0 mg/L to 10 mg/L, 2 orders of magnitude
would permit the minimum and maximum calibration standards of 0.20 mg/L and
20 mg/L, respectively.) The restriction of 2 orders of magnitude is prescribed
since beyond this it is difficult to maintain linearity throughout the entire
calibration range.
10.2.1 If quantification is desired over a larger range, then two separate
calibration curves should be prepared.
10.2.2 For an individual calibration curve, a minimum of three calibration
standards are required for a curve that extends over a single order of
magnitude and a minimum of five calibration standards are required if the
curve covers two orders of magnitude. (For example, using the nitrate
example cited above in section 10.2, but in this case limit the curve to
extend only from 1.0 mg/L to 10 mg/L or a single order of magnitude. A
third standard is required somewhere in the middle of the range. For the
calibration range of 0.20 mg/L to 20 mg/L, over two orders of
magnitude, five calibrations standards should be employed, one each at
the lower and upper concentration ranges and the other three
proportionally divided throughout the middle of the curve.)
10.3 Prepare the calibration standards by carefully adding measured volumes of one or
more stock standards (7.3) to a volumetric flask and diluting to volume with
reagent water.
10.3.1 For the Part B anions, EDA must be added to the calibration standards at
50 mg/L. The addition of EDA to all reagent water prepared calibration
and quality control samples is required not as a preservative but rather as
a means to normalize any bias attributed by the presence of EDA in the
field samples.
10.3.2 Prepare a 10.0 mL aliquot of surrogate fortified calibration solution
which can be held for direct manual injection or used to fill an
autosampler vial. Add 20 uL of the surrogate solution (7.5) to a 20 mL
disposable plastic micro beaker. Using a 10.0 mL disposable pipet, place
300.1-19
-------
exactly 10.0 mL of calibration standard into the micro beaker and mix.
The calibration standard is now ready for analysis. The same surrogate
solution that has been employed for the standards should also be used in
the section 11.3.2 for the field samples.
10.4 Using a 2 mm column, inject 10 uL (Part A) or 50 uL (Part B) of each calibration
standard. Using a 4 mm column, inject 50 uL (Part A) or 200 uL (Part B) of each
calibration standard. Tabulate peak area responses against the concentration.
The results are used to prepare calibration curves using a linear least squares fit
for each analyte. Acceptable calibration curves are confirmed after reviewing the
curves for linearity and passing the criteria for the initial calibration check
standard in section 10.5.1. Alternately, if the ratio of response to concentration
(response factor) is constant over the LCR (indicated by < 15% relative standard
deviation (RSD), linearity through the origin can be assumed and the average
ratio or calibration factor can be used in place of a calibration curve,
10.4.1 Peak areas are strongly recommended since they have been found to be
more consistent, in terms of quantitation, than peak heights. Peak height
can tend to be suppressed as a result of high levels of common anions in a
given matrix which can compete for exchange sites. Using peak areas, it
is the analyst responsibility to review all chromatograms to insure
accurate baseline integration of target analyte peaks since poorly drawn
baselines will more significantly influence peak areas than peak heights.
10.5 Once the calibration curves have been established they must be verified prior to
conducting any sample analysis using an initial calibration check standard (3.2.2).
This verification must be performed on each analysis day or whenever fresh eluent
has been prepared. A continuing calibration check standard (3.2.3) must be
analyzed after every tenth sample and at the end of the analysis set as an end
calibration check standard (3.2.4). The response for the initial, continuing and end
calibration check must satisfy the criteria listed in 10.5.1. If during the analysis set,
the response differs by more than the calibration verification criteria shown in
10.5.1., or the retention times shift more than ± 5% from the expected values for
any analyte, the test must be repeated, using fresh calibration standards. If the
results are still outside these criteria, sample analysis must be discontinued, the
cause determined and/or in the case of drift, the instrument recalibrated. All
samples following the last acceptable calibration check standard must be
reanalyzed.
10.5.1 Control limits for calibration verification
Concentration range Percent Recovery Limits
MRL to lOxMRL 75-125 %
1 OxMRL to highest calibration level 85 - 115 %
10.5.1.1 These control limits only apply if the MRL i s establi shed within
a factor of 10 times the MDL. Otherwise, the limits are set at
85% to 115%.
300.1-20
-------
10.5.2 CALIBRATION VERIFICATION REQUIREMENT FOR PART B
As a mandatory requirement of calibration verification, the laboratory
MUST verify calibration using the lowest calibration standard as the
initial calibration check standard.
10.5.3 After satisfying the requirement of 10.5.2, the levels selected for the other
calibration check standards should be varied between a middle calibration
level and the highest calibration level.
11. PROCEDURE
11.1 Tables 1A and IB summarize the recommended operating conditions for the ion
chromatograph. Included in these tables are estimated retention times that can be
achieved by this method. Other columns, chromatographic conditions, or
detectors may be used if the requirements of Sect. 9.2 are met.
11.2 Check system calibration daily and, if required, recalibrate as described in Sect.
10.
11.3 Sample Preparation
11.3.1 For refrigerated or samples arriving to the laboratory cold, ensure the
samples have come to room temperature prior to conducting sample
analysis by allowing the samples to warm on the bench for at least 1 hour.
11.3.2 Prepare a 10.0 mL aliquot of surrogate fortified sample which can be held
for direct manual injection or used to fill an autosampler vial. Add 20 uL
of the surrogate solution (7.5) to a 20 mL disposable plastic micro beaker.
Using a 10.0 mL disposable pipet, place exactly 10.0 mL of sample into
the micro beaker and mix. Sample is now ready for analysis.
11.3.2.1 The less than 1% dilution error introduced by the addition of the
surrogate is considered insignificant.
11.4 Using a Luer lock, plastic 10 mL syringe, withdraw the sample from the micro
beaker and attach a 0.45 um particulate filter (demonstrated to be free of ionic
contaminants) directly to the syringe. Filter the sample into an autosampler vial
(If vial is not designed to automatically filter) or manually load the injection loop
injecting a fixed amount of well mixed sample. If using a manually loaded
injection loop, flush the loop thoroughly between sample analysis using sufficient
volumes of each new sample matrix.
11.5 Using a 2 mm column, inject 10 uL (Part A) or 50 uL (Part B) of each sample.
Using a 4 mm column, inject 40 uL (Part A) or 200 uL (Part B) of each sample.
Tabulate peak area responses against the concentration. During this procedure,
retention times must be recorded. Use the same size loop for standards and
300.1-21
-------
samples. Record the resulting peak size in area units. An automated constant
volume injection system may also be used.
11.6 The width of the retention time window used to make identifications should be
based upon measurements of actual retention time variations of standards over the
course of a day. Three times the standard deviation of a retention time can be
used to calculate a suggested window size for each analyte. However, the
experience of the analyst should weigh heavily in the interpretation of
chromatograms.
11.7 If the response of a sample analyte exceeds the calibration range, the sample may
be diluted with an appropriate amount of reagent water and reanalyzed. If this is
not possible then three new calibration concentrations must be employed to create
a separate high concentration curve, one standard near the estimated
concentration and the other two bracketing around an interval equivalent to ±
25% the estimated concentration. The latter procedure involves significantly
more time than a simple sample dilution therefore, it is advisable to collect
sufficient sample to allow for sample dilution or sample reanalysis, if required.
11.8 Shifts in retention time are inversely proportional to concentration. Nitrate,
phosphate and sulfate will exhibit the greatest degree of change, although all
anions can be affected. In some cases this peak migration may produce poor
resolution or make peak identification difficult.
11.9 Should more complete resolution be needed between any two coeluting peaks, the
eluent (7.2) can be diluted. This will spread out the run, however, and will cause
late eluting anions to be retained even longer. The analysts must verify that this
dilution does not negatively affect performance by repeating and passing all the QC
criteria in Section 9. As a specific precaution, upon dilution of the carbonate
eluent, a peak for bicarbonate may be observed within the retention time window
for bromate which will negatively impact the analysis.
11.9.1 Eluent dilution will reduce the overall response of an anion due to
chromatographic band broadening which will be evident by shortened
and broadened peaks. This will adversely effect the MDLs for each
analyte.
12. DATA ANALYSIS AND CALCULATIONS
12.1 Prepare a calibration curve for each analyte by plotting instrument response, as
peak area, against standard concentration. Compute sample concentration by
comparing sample response with the standard curve. If a sample has been
diluted, multiply the response by the appropriate dilution factor.
12.2 Report ONLY those values that fall between the lowest and the highest
calibration standards. Samples with target analyte responses exceeding the
highest standard should be diluted and reanalyzed. Samples with target analytes
identified but quantitated below the concentration established by the lowest
300.1-22
-------
calibration standard should be reported as below the minimum reporting limit
(MRL).
12.3 Report results for Part A anions in mg/L and for Part B anions in ug/L.
12.4 Report NO2' asN
NO3- asN
HPO4= as P
Br" in mg/L when reported with Part A
Br" in ug/L when reported with Part B
13. METHODS PERFORMANCE
13.1 Tables 1 A, IB, and 1C give the single laboratory (OW OGWDW TSC-
Cincinnati) retention times, standard conditions and MDL determined for each
anion included in the method. MDLs for the Part A anions were determined in
reagent water on the 2 mm column (Table 1 A). MDLs for the Part B anions were
conducted not only in reagent water but also a simulated high ionic strength water
(HIW) on the 2 mm column (Table IB) and in reagent water on the 4 mm column
(Table 1C). HIW is designed to simulate a high ionic strength field sample. It
was prepared from reagent water which was fortified with the common anions of
chloride at 100 mg/L, carbonate at 100 mg/L, nitrate at 10.0 mg/L as nitrogen,
phosphate at 10.0 mg/L as phosphorous, and sulfate at 100 mg/L.
13.2 Tables 2A and 2B give the single laboratory (OW OGWDW TSC-Cincinnati)
standard deviation for each anion included in the method in a variety of waters for
the standard conditions identified in Table 1A and IB, respectively.
13.3 Tables 3A and 3B shown stability data for the Part A and B anions, respectively.
Each data point in these tables represent the mean percent recovery following
triplicate analysis. These data were used to formulate the holding times shown in
Sect. 8.3.
14. 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 operation. 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 Quantity of the chemicals purchased should be based on expected usage during its
shelf life and disposal cost of unused material. Actual reagent preparation
volumes should reflect anticipated usage and reagent stability.
300.1-23
-------
14.3 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 Regulations and Science Policy, 1155 16th
Street N.W., Washington D.C. 20036,
(202) 872-4477.
15. WASTE MANAGEMENT
15.1 The Environmental Protection Agency requires that laboratory waste
management practices be conducted consistent with all applicable rules and
regulations. Excess reagents, samples and method process wastes should be
characterized and disposed of in an acceptable manner. 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 waste discharge permit 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 Sect. 14.3.
16. REFERENCES
1. "Determination of Inorganic Disinfection By-Products by Ion Chromatography",
J. Pfaff, C. Brockhoff. J. Am. Waterworks Assoc., Vol 82, No. 4, pg 192.
2. Standard Methods for the Examination of Water and Wastewater, Method
4110B, "Anions by Ion Chromatography", 18th Edition of Standard Methods
(1992).
3. Dionex, System DX500 Operation and Maintenance Manual, Dionex Corp.,
Sunnyvale, California 94086, 1996.
4. Method Detection Limit (MDL) as described in "Trace Analyses for
Wastewater," J. Glaser, D. Foerst, G. McKee, S. Quave, W. Budde,
Environmental Science and Technology, Vol. 15, Number 12, page 1426,
December, 1981.
5. American Society for Testing and Materials. Test Method for Anions in Water by
Chemically-Suppressed Ion Chromatography D4327-91. Annual Book of
Standards, Vol 11.01(1993).
6. Code of Federal Regulations 40, Ch. 1, Pt. 136, Appendix B.
7. Hautman, D.P. & Bolyard, M. Analysis of Oxyhalide Disinfection By-products
and other Anions of Interest in Drinking Water by Ion Chromatography. Jour, of
Chromatog., 602, (1992), 65-74.
300.1-24
-------
Standard Methods for the Examination of Water and Wastewater, Method 4500-
C1O 2,C " Amperometric Method I" (for the determination of Chlorine Dioxide),
19th Edition of Standard Methods (1995).
300.1-25
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17. TABLES, DIAGRAMS, FLOWCHARTS AND VALIDATION DATA
TABLE 1A. CHROMATOGRAPHIC CONDITIONS AND METHOD DETECTION
LIMITS IN REAGENT WATER FOR THE COMMON ANIONS (PART
A).
ANALYTE
Fluoride
Chloride
Nitrite-N
Surrogate: DC A
Bromide
Nitrate-N
ortho-Phosphate-P
Sulfate
PEAK # (1)
1
2
3
4
5
6
7
8
RETENTION TIME
(MIN.)
2.53
4.67
6.01
7.03
8.21
9.84
11.98
13.49
MDL
Fort Cone,
mg/L
0.020
0.020
0.010
0.040
0.010
0.040
0.040
DETERMINATION
Number
of
Replicates
7
7
7
7
7
7
7
DI
MDL
mg/L
0.009
0.004
0.001
0.014
0.008
0.019
0.019
Standard Conditions:
Ion Chromatograph:
Columns :
Detector:
Suppressor:
Eluent:
Eluent Flow:
Sample Loop:
Dionex DX500
Dionex AG9-HC / AS9-HC, 2 mm
Suppressed Conductivity Detector, Dionex CD20
ASRS-I, external source electrolytic mode, 100 mA current
9.0 mM Na2CO3
0.40 mL/min
10 uL
System Backpressure: 2800 psi
Background Conductivity: 22 uS
Recommended method total analysis time: 25 minutes
(1) See Figure 1
300.1-26
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TABLE IB. CHROMATOGRAPHIC CONDITIONS AND METHOD
DETECTION LIMITS IN BOTH REAGENT WATER AND HIGH
IONIC STRENGTH WATER FOR THE INORGANIC
DISINFECTION BY-PRODUCTS (PART B).
ANALYTE
Chlorite
Bromate
Surrogate:
DCA
Bromide
Chlorate
PEAK # (1)
1
2
4
5
6
RETENTION
TIME
(MIN.)
3.63
4.19
7.28
8.48
9.28
MDL DETERMINATION
Fort
Cone,
ug/L
2.00
2.00
2.00
2.00
Number
of
Replicates
7
7
7
7
DI
MDL
ug/L
0.89
1.44
1.44
1.31
fflW(2)
MDL
ug/L
0.45
1.28
2.51
0.78
Standard Conditions:
Ion Chromatograph:
Columns :
Detector:
Suppressor:
Eluent:
Eluent Flow:
Sample Loop:
Dionex DX500
Dionex AG9-HC / AS9-HC, 2 mm
Suppressed Conductivity Detector, Dionex CD20
ASRS-I, external source electrolytic mode, 100 mA current
9.0 mM Na2CO3
0.40 mL/min
50 uL
System Backpressure: 2800 psi
Background Conductivity: 22 uS
Recommended method total analysis time: 25 minutes
(1) See Figure 2 and 3
(2) HIW indicates High Ionic Strength Water which is a simulated drinking water prepared
from reagent water and fortified with chloride at 100 mg/L, carbonate at 100 mg/L,
nitrate at 10.0 mg/L as nitrogen, phosphate at 10.0 mg/L as phosphorous, and sulfate at
100 mg/L.
300.1-27
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TABLE 1C. CHROMATOGRAPHIC CONDITIONS AND METHOD
DETECTION LIMITS IN REAGENT WATER FOR THE
INORGANIC DISINFECTION BY-PRODUCTS USING AN
ALTERNATE 4 mm AS9-HC COLUMN (PART B).
ANALYTE
Chlorite
Bromate
Surrogate:
DCA
Bromide
Chlorate
PEAK#
1
2
4
5
6
RETENTION
TIME
(MIN.)
4.43
5.10
8.82
10.11
10.94
MDL
Fort
Cone,
ug/L
2.00
2.00
2.00
2.00
DETERMINATION
Number
of
Replicates
7
7
7
7
DI
MDL
ug/L
1.44
1.32
0.98
2.55
Standard Conditions:
Ion Chromatograph:
Columns :
Detector:
Suppressor:
Eluent:
Eluent Flow:
Sample Loop:
Dionex DX500
Dionex AG9-HC / AS9-HC, 4 mm
Suppressed Conductivity Detector, Dionex CD20
ASRS-I, external source electrolytic mode, 300 mA current
9.0 mM Na2CO3
1.25 mL/min
200 uL
System Backpressure: 1900 psi
Background Conductivity: 21 uS
Recommended method total analysis time: 25 minutes
300.1-28
-------
TABLE 2A. SINGLE-OPERATOR PRECISION AND RECOVERY FOR THE
COMMON
ANIONS (PART A).
UNFORT FORT #
MATRIX CONC OF MEAN MEAN
ANALYTE MATRIX CONC., mg/L REPLC mg/L %REC SD(n-l)
mg/L
Fluoride
Chloride
Nitrite-N
Bromide
Nitrate-N
Phosphate-P
Sulfate
Surrogate:
RW
SW
GW
CDW
RW
SW
GW
CDW
RW
SW
GW
CDW
RW
SW
GW
CDW
RW
SW
GW
CDW
RW
SW
GW
CDW
RW
SW
GW
CDW
RW
SW
GW
CDW
-------
TABLE 2B. SINGLE-OPERATOR PRECISION AND RECOVERY FOR THE
INORGANIC DISINFECTION BY-PRODUCTS (PART B).
ANALYTE MATRIX
Chlorite RW
HIW
SW
GW
C1W
CDW
O3W
Bromate RW
HIW
SW
GW
C1W
CDW
O3W
UNFORT
CONC.
ug/L
-------
TABLE 2B. SINGLE-OPERATOR PRECISION AND RECOVERY FOR THE INORGANIC
DISINFECTION BY-PRODUCTS (PART B) (contd.).
UNFORT
CONC.
ANALYTE MATRIX ug/L
Bromide RW
HIW
SW
GW
C1W
CDW
O3W
Chlorate RW
HIW
SW
GW
C1W
CDW
O3W
-------
TABLE 2B. SINGLE-OPERATOR PRECISION AND RECOVERY FOR THE INORGANIC
DISINFECTION BY-PRODUCTS (PART B)(contd.).
ANALYTE
Surrogate: DC A
(see NOTE below)
MATRIX
RW
HIW
SW
GW
C1W
CDW
O3W
FORT
CONC
mg/L
5.00
5.00
5.00
5.00
5.00
5.00
5.00
#
OF
REPLC
9
9
9
9
9
9
9
MEAN
mg/L
5.11
4.98
5.00
4.96
4.95
4.99
5.12
5.13
5.15
5.13
5.01
5.04
4.99
5.11
MEAN
%REC
102
99.5
100
99.2
98.9
99.8
102
103
103
103
100
101
99.8
101
SD(n-l)
0.93
0.69
0.79
1.76
0.70
1.60
0.50
0.50
1.73
1.12
1.02
1.08
0.70
0.53
%RSD
0.91
0.69
0.79
1.78
0.7
1.61
0.49
0.49
1.68
1.09
1.02
1.07
0.7
0.52
RW = Reagent Water
HIW = High Ionic strength Water
[see note (2) in Table IB]
SW= Surface Water
GW = Groundwater
C1W = Chlorinated drinking water
CDW = Chlorine dioxide treated drinking water
O3W = Ozonated drinking water
NOTE:
The surrogate DCA was fortified at 5 mg/L but due to concerns about measuring trace
concentrations of bromide with such high concentration of the neighboring surrogate
peak, the recommended fortified concentration for the surrogate has been reduced to
1.00 mg/L.
300.1-32
-------
TABLE 3A. STABILITY STUDY RESULTS FOR THE COMMON ANIONS (PART A).
ANALYTE Preservative
Fluoride None
Chloride None
Nitrite-N None
Bromide None
Nitrate-N None
Phosphate-P None
Sulfate None
Matrix
RW
SW
GW
CDW
RW
SW
GW
CDW
RW
SW
GW
CDW
RW
SW
GW
CDW
RW
SW
GW
CDW
RW
SW
GW
CDW
RW
SW
GW
CDW
UNFORT
CONC.
mg/L
-------
TABLE 3B STABILITY STUDY RESULTS FOR THE INORGANIC DISINFECTION BY-
PRODUCTS (PARTB).
ANALYTE Preservative
Chlorite None
Chlorite EDA
Bromate None
Bromate EDA
Matrix
RW
HIW
SW
GW
C1W
CDW
O3W
RW
HIW
SW
GW
C1W
CDW
O3W
RW
HIW
SW
GW
C1W
CDW
O3W
RW
HIW
SW
GW
C1W
CDW
O3W
UNFORT
CONC.
ug/L
-------
TABLE 3B. STABILITY STUDY RESULTS FOR THE INORGANIC DISINFECTION
BY-PRODUCTS (PART B)(contd.)
ANALYTE Preservative
Bromide None
Bromide EDA
Chlorate None
Chlorate EDA
Matrix
RW
HIW
SW
GW
C1W
CDW
O3W
RW
HIW
SW
GW
C1W
CDW
O3W
RW
HIW
SW
GW
C1W
CDW
O3W
RW
HIW
SW
GW
C1W
CDW
O3W
UNFORT
CONC.
ug/L
-------
Peak Ret. Time
I^A 1 2-53
DU 2 4.67
— i
|jS
-2 -]
3 6.01
2 4 7.03
1
5 8.21
6 9.84
7 11.98
8 13.49
* The surrogate,
Anion
Fluoride
Chloride
Nitrite-N
Dichloroacetate*
Bromide
Nitrate-N
O- Phosphate- P
Sulfate
dichloroacetate (DCA)
mg/L
3.20
32.0
3.20
5.00
3.20
3.20
8.00
36.8
,is shown at the
recommended concentration of 5.00 mg/L for Part A.
3
.
f[ 4 5
8
A
6 7 A
A /vj\
k.
i i i i i i i i i i i i i i i i i i
I i i i I i i i
0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.
Minutes
1
00
Figure 1. Chromatogram showing separation of the Part A common anions on the AS9-HC column.
See Table 1A for analysis conditions.
300.1-36
-------
Peak Ret. Time
MS
0
I I I
.00
3.63
4.19
4.83
7.28
8.48
9.28
Anion
Chlorite
Bromate
Chloride
Dichloroacetate*
Bromide
Chlorate
ug/L
500
500
Bkgrd
5.00 mg/L
500
500
The surrogate, dichloroacetate (DCA) ,is shown at
5.00 mg/L, the initial concentration used during
method development. The recommended DCA
concentration has been reduced to 1 .00 mg/L for
Part B.
I I
I I I
I
I I I
\ \\
i i i
4.00 6.00 8.00 10.00
Minutes
12.00 14.00
Figure 2 Chromatogram showing separation of the Part B inorganic DBFs and bromide on the AS9-HC
column. See Table IB for analysis conditions.
300.1-37
-------
0.3
uS
0
\ \ \
0.00
>.oo
Peak
1
2
3
4
5
6
Ret. Time
3.63
4.19
4.83
7.28
8.48
9.28
Anion
Chlorite
Bromate
Chloride
Dichloroacetate*
Bromide
Chlorate
ug/L
2.00
2.00
Bkgrd
1.00 mg/L
2.00
2.00
The surrogate, dichloroacetate (DCA) is shown at
the recommended concentration of 1 .OOmg/L for
PartB.
i i i i i i i i i r
4.00 6.00 8.00 10.00
Minutes
\ \ \ \ \
12.00 14.00
Figure 3. Chromatogram of the inorganic DBFs and bromide (Part B) during the MDL determination in
reagent water. See Table IB for analysis conditions.
300.1-38
-------
1
0
8
3.
4.1
4.
7.
8.
9.
D.3
,2.5
14.0
63
9
8i3
8
48
8
Anion
Chlorite
Bromate
Chloride
DCA*
Bromide
Chlorate
Nitrate-N
Phosphate-P
Sulfate
ug/L
1DD
5.0D
1DOmg/L
5.DD mg/L
20.D
1DD
10.0 mg/L
10.0 mg/L
100 mg/L
The surrogate, dichloroacetate (DCA) ,is
shown\at 5.00 mg/L, the initial concentration
used during method development. The
recommended DCA concentration has been
reduced to 1.00 mg/L for Part B.
i i r
i i r
i i r
i i r
0.00
6.00 8.00 10.00 12.00 14.00
Minutes
Figure 4. Chromatogram of the inorganic DBFs and bromide (Part B) in high ionic strength water (HIW). See
Table IB for analysis conditions.
300.1-39
------- |