&EPA
METHOD 302.0: DETERMINATION OF BROMATE IN
DRINKING WATER USING TWO-DIMENSIONAL ION
CHROMATOGRAPHY WITH SUPPRESSED
CONDUCTIVITY DETECTION
Office of Water (MLK 140) EPA Document No. 815-B-09-014 September 2009 www.epa.gov/safewater
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METHOD 302.0 DETERMINATION OF BROMATE IN DRINKING WATER USING
TWO-DIMENSIONAL ION CHROMATOGRAPHY WITH SUPPRESSED
CONDUCTIVITY DETECTION
Version 1.0
September 2009
Herbert P. Wagner (Lakeshore Engineering Services, Inc.)
Barry V. Pepich (Shaw Environmental, Inc.)
Chris Pohl, Kan nan Srinivasan, Brian De Borba, Rong Lin (Dionex Corp.)
David J. Munch (U.S. EPA, Office of Ground Water and Drinking Water)
TECHNICAL SUPPORT CENTER
OFFICE OF GROUND WATER AND DRINKING WATER
U. S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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METHOD 302.0
DETERMINATION OF BROMATE IN DRINKING WATERS USING TWO-DIMENSIONAL
ION CHROMATOGRAPHY WITH SUPPRESSED CONDUCTIVITY DETECTION
1. SCOPE AND APPLICATION
1.1 This is a large volume (1.0 mL), two-dimensional (2-D) ion chromatographic (1C) method
using suppressed conductivity detection for the determination of bromate in raw and finished
drinking waters. Because this method utilizes two dissimilar 1C columns it does not require
second column confirmation. Detection and quantitation in the second dimension are
accomplished by suppressed conductivity detection. Precision and accuracy data have been
generated for bromate using this 2-D 1C method in reagent water, finished groundwater,
finished surface water and a Laboratory Fortified Synthetic Sample Matrix (LFSSM). The
single laboratory Lowest Concentration Minimum Reporting Level (LCMRL) has also been
determined in reagent water.l
Chemical Abstract Services
Analvte Registry Number (CASRN)
Bromate 15541-45-4
1.2 The Minimum Reporting Level (MRL) is the lowest analyte concentration that meets Data
Quality Objectives (DQOs) that are developed based on the intended use of this method. The
single laboratory LCMRL is the lowest true concentration for which the future recovery is
predicted to fall between 50 and 150 percent recovery with 99% confidence. The single
laboratory LCMRL for bromate was 0.18 ug/L using a 1.0-mL injection volume (see Table 2).
The procedure used to determine the LCMRL is described elsewhere.l
1.3 Laboratories using this method will not be required to determine the LCMRL, but will need to
demonstrate that their laboratory MRL for this method meets the requirements described in
Section 9.2.4.
1.4 Detection Limit (DL) is defined as the statistically calculated minimum concentration that can
be measured with 99% confidence that the reported value is greater than zero. The DL for
bromate is dependent on sample matrix, fortification concentration, and instrument
performance. Determining the DL for bromate in this method is optional (Sect. 9.2.6). The
reagent water DL for bromate using a 1.0-mL injection volume was calculated to be 0.12 |ig/L
using 7 reagent water (RW) replicates fortified at 0.20 |ig/L (see Table 2).
1.5 This method is intended for use by analysts skilled in the operation of 1C instrumentation, and
the interpretation of the associated data.
1.6 METHOD FLEXIBILITY - In recognition of technological advances in analytical systems
and techniques, the laboratory is permitted to modify the separation technique, 1C columns,
concentrator column and mobile phase composition. However, any modifications must
maintain the basic chromatographic elements of this new technique. This includes the initial
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separation of analytes on a primary 1C column that are heart-cut after suppression and directed
to a concentrator column. After concentration, analytes must then be eluted onto a second,
dissimilar 1C column for separation and quantitation. For high sensitivity applications, the
system should have a second-dimension column with a lower cross sectional area, which
operates at a relatively lower flow rate in order to achieve sensitivity enhancement
proportional to the ratio of the flow rate reduction. Method modifications should be
considered only to improve method performance. Modifications that are introduced in the
interest of reducing cost or sample processing time, but result in poorer method performance
(see Sect. 9.4 for criteria), may not be used. In all cases where method modifications are
proposed, the analyst must first redetermine the cut window and establish an acceptable
calibration. Then the analyst must demonstrate acceptable method performance by
conducting the procedures outlined in the initial demonstration of capability (IDC, Sect. 9.2),
verifying that all ongoing QC acceptance criteria can be routinely met (Tables 4 and 5), and
properly documenting the method changes (Sect. 9.4). Changes may not be made to sample
collection and preservation (Sect. 8) or to the quality control requirements (Sect. 9).
2. SUMMARY OF METHOD
2.1 Water samples are collected in the field using normal collection techniques and dechlorinated
with ethylenediamine (EDA). A 1.0-mL sample aliquot is injected onto a 4-mm 1C column.
Separation of bromate is achieved in the first dimension (1-D) using 10 mM KOH at a flow
rate of 1.0 mL per minute. Approximately 2 mL of the suppressed eluent containing the
bromate is diverted from the first dimension column to a concentrator column used in place of
the sample loop of the second dimension (2-D) injection valve. The concentrator column has
low backpressure but sufficient capacity to trap the bromate ions quantitatively in the
suppressed eluent. In this manner, bromate is separated from other matrix ions and
concentrated on a trapping column. The heart-cut portion of the 1-D chromatogram is eluted
off the concentrator column and onto a smaller diameter (2 mm diameter) guard and analytical
column that have different selectivity from the first dimension columns to facilitate the 2-D
separation using 10 mM KOH at a flow rate of 0.25 mL per minute. Bromate is quantitated
using the external standard method.
There are several advantages to this version of the method. This version is compatible with a
large sample injection volume (up tol.O-mL). This is due to the high capacity of the 1-D
analytical column and its higher selectivity for bromate relative to the other matrix ions. The
suppressed eluent from the first dimension column, which is essentially water containing the
anions of interest and a subset of the matrix interferences that co-elute in the heart-cut
window, are efficiently retained and refocused on the concentrator column. Because the
second dimension is operated at a lower flow rate relative to the first dimension and uses a
smaller cross sectional area column, this version of the method offers enhanced sensitivity.
The increase in sensitivity of the present setup is directly proportional to the flow rate ratio of
the first dimension to the second dimension columns. This yields method sensitivity
comparable to the EPA bromate methods that utilize the addition of postcolumn reagents
(317.0 and 326.0) and UV/Vis detection. Finally, the 2-D 1C method combines two columns
with different selectivity thereby eliminating the need for second column confirmation.
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3. DEFINITIONS
3.1 ANALYSIS BATCH - A sequence of field samples, which are analyzed within a 24-hour
period and include no more than 20 field samples. An Analysis Batch must also include all
required QC samples, which do not contribute to the maximum field sample total of 20. For
this method, the required QC samples include:
Laboratory Reagent Blank (LRB)
Continuing Calibration Check (CCC) Standards
Laboratory Fortified Sample Matrix (LFSM)
Laboratory Duplicate (LD) or a Laboratory Fortified Sample Matrix Duplicate
(LFSMD)
Laboratory Fortified Synthetic Sample Matrix CCC Standard (LFSSM CCC)
3.2 ANALYTE FORTIFICATION SOLUTIONS (AFS) - The Analyte Fortification Solutions
are prepared by dilution of the Analyte Secondary Dilution Solutions (SDS) and are used to
fortify the LFSMs and the LFSMDs with bromate. It is recommended that multiple
concentrations be prepared so that the fortification levels can be rotated or adjusted to the
concentration of target analyte in the native samples.
3.3 CALIBRATION STANDARD (CAL) - A solution of the target analyte prepared from the
Bromate Primary Dilution Solution or Bromate Stock Standard Solution. The CAL solutions
are used to calibrate the instrument response with respect to analyte concentration.
3.4 CONTINUING CALIBRATION CHECK STANDARD (CCC) - A calibration check
standard containing the method analyte which is analyzed periodically throughout an
Analysis Batch, to verify the accuracy of the existing calibration for that analyte.
3.5 DETECTION LIMIT (DL) - The minimum concentration of an analyte that can be identified
measured and reported with 99% confidence that the analyte concentration is greater than
zero. This is a statistical determination (Sect. 9.2.6), and accurate quantitation is not
expected at this level.2
3.6 LABORATORY DUPLICATE (LD) - Two sample aliquots (LDi and LD2), from a single
field sample bottle, and analyzed separately with identical procedures. Analyses of LDi and
LD2 indicate precision associated specifically with laboratory procedures by removing
variation contributed from sample collection and storage procedures.
3.7 LABORATORY FORTIFIED BLANK (LFB) - An aliquot of reagent water or other blank
matrix to which a known quantity of the method analyte is added. The LFB is analyzed
exactly like a sample. Its purpose is to determine whether the methodology is in control, and
whether the laboratory is capable of making accurate and precise measurements.
3.8 LABORATORY FORTIFIED SAMPLE MATRIX (LFSM) - An aliquot of a field sample to
which a known quantity of the method analyte is added. The LFSM is processed and
analyzed exactly like a field sample, and its purpose is to determine whether the field sample
matrix contributes bias to the analytical results. The background concentration of the analyte
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in the field sample matrix must be determined in a separate aliquot and the measured value in
the LFSM corrected for the native concentration.
3.9 LABORATORY FORTIFIED SAMPLE MATRIX DUPLICATE (LFSMD) - A second
aliquot of the field sample used to prepare the LFSM, which is fortified and analyzed
identically to the LFSM. The LFSMD is used instead of the Laboratory Duplicate to assess
method precision and accuracy when the occurrence of the target analyte is infrequent.
3.10 LABORATORY FORTIFIED SYNTHETIC SAMPLE MATRIX (LFSSM) - An aliquot of
the LSSM (Sect. 7.2.2) which is fortified with bromate. The LFSSM is used to set the start
time for the cut window in the 1-D during the initial demonstration of capability (IDC) (Sect.
9.2). The LFSSM is also used to determine the precision and accuracy of the method during
the IDC (Sects. 9.2.2 and 9.2.3). The LFSSM samples are treated like the CCCs.
3.11 LABORATORY FORTIFIED SYNTHETIC SAMPLE MATRIX CONTINUING
CALIBRATION CHECK STANDARD (LFSSM CCC) - An aliquot of the LSSM (Sect.
7.2.2) which is fortified with bromate at a concentration equal to one of the CCCs. In this
method, a LFSSM CCC at a concentration equal to the highest calibration level should be
analyzed near the beginning of each Analysis Batch (Sect. 9.3.3) to confirm that the 1-D
heart cutting procedure has acceptable recovery in high inorganic matrices.
3.12 LABORATORY REAGENT BLANK (LRB) - An aliquot of reagent water or other blank
matrix that is treated exactly as a sample including exposure to storage containers. The LRB
is used to determine if the method analyte or other interferences are present in the laboratory
environment, the reagents, or the apparatus.
3.13 LABORATORY SYNTHETIC SAMPLE MATRIX (LS SM) - An aliquot of reagent water
that is fortified with 100 mg/L of the sodium salts of chloride, bicarbonate and sulfate and 10
mg/L phosphate as phosphorus and nitrate as nitrogen using the sodium salts of phosphate
and nitrate.
3.14 LOWEST CONCENTRATION MINIMUM REPORTING LEVEL (LCMRL) - The single-
laboratory LCMRL is the lowest true concentration for which the future recovery is predicted
to fall between 50 and 150 percent recovery with 99% confidence. l
3.15 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.
3.16 MINIMUM REPORTING LEVEL (MRL) - The minimum concentration that can be
reported by a laboratory as a quantified value for the target analyte in a sample following
analysis. This defined concentration must meet the criteria defined in Section 9.2.4 and must
be no lower than the concentration of the lowest calibration standard for the target analyte.
3.17 PRIMARY DILUTION STANDARD SOLUTION (PDS) - A solution containing the
method analyte prepared in the laboratory from stock standard solutions and diluted as
needed to prepare calibration solutions and other analyte-containing solutions.
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3.18 QUALITY CONTROL SAMPLE (QCS) - A solution containing the method analyte at a
known concentration that is obtained from a source external to the laboratory and different
from the source of calibration standards. The QCS is used to verify the accuracy of the
calibration standards and the integrity of the calibration curve.
3.19 REAGENT WATER (RW) - Purified water which does not contain any measurable quantity
of the target analyte or interfering compounds at or above 1/3 the MRL.
3.20 SECONDARY DILUTION STANDARD SOLUTION (SDS) - A solution containing the
method analyte prepared in the laboratory from the PDS and diluted as needed to prepare
calibration solutions and other analyte solutions.
3.21 STOCK STANDARD SOLUTION (SSS) - A concentrated solution containing the method
analyte prepared in the laboratory using assayed reference materials or purchased from a
reputable commercial source, so that the concentration and purity of analytes are traceable to
certificates of analysis.
4. INTERFERENCES
4.1 Interferences can be divided into three different categories: (i) direct chromatographic co-
elution, where an analyte response is observed at very nearly the same retention time (RT) as
the target analyte; (ii) concentration dependant co-elution, which is observed when the
response of higher than typical concentrations of the neighboring peak overlaps into the
retention window of the target analyte; and (iii) ionic character displacement, where retention
times may significantly shift due to the influence of high ionic strength matrices (high mineral
content or total dissolved solids) overloading the exchange sites on the column and
significantly shortening the target analyte's retention time.
4.1.1 A direct chromatographic co-elution may be solved by changing column selectivity in
one or both dimensions of the 2-D 1C method, adjusting eluent strength in one or both
dimensions, modifying the eluent with organic solvents (if compatible with 1C columns),
changing the detection system, or selective removal of the interference with sample
pretreatment. Sample dilution will have little to no effect on direct chromatographic co-
elution. The analyst must verify that any change made to the chromatographic
parameters does not induce any negative affects on method performance by repeating and
passing all the QC criteria as described in Section 9.2.
4.1.2 Sample dilution may resolve some of the difficulties if the interference is the result of
either concentration dependant co-elution or ionic character displacement, but it must be
clarified that sample dilution will alter the MRL by a proportional factor equivalent to
that of the dilution. Therefore, careful consideration of Data Quality Objectives (DQOs)
should be given prior to performing such a dilution.
4.2 Method interferences may be caused by contaminants in solvents, reagents (including reagent
water), sample bottles and caps, and other sample processing hardware that lead to discrete
artifacts and/or elevated baselines in the chromatograms. All items such as these must be
routinely demonstrated to be free from interferences (less than Vs the bromate MRL) by
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analyses of an LRB as described in Section 9.2.1. Subtracting blank values from sample
results is not permitted.
4.3 Matrix interferences may be caused by contaminants that are present in the sample. The
extent of matrix interferences will vary considerably from source to source, depending upon
the nature of the water. Water samples high in organic carbon or total dissolved solids may
have elevated baselines or interfering peaks.
4.3.1 Equipment and containers used for sample collection and storage have the potential to
introduce interferences. The potential for interferences from these sources must be
investigated during the IDC (Sect. 9.2) by preparing and analyzing a LRB. This
procedure should be repeated each time that a new brand and/or lot of materials are used
to ensure that contamination does not hinder analyte identification and quantitation.
4.4 When first-dimension heart-cut windows are properly set, this method demonstrates adequate
performance in water matrices that contain up to 100 mg/L of each common anion (sulfate,
bicarbonate, and chloride), and phosphate as phosphorus and nitrate as nitrogen at 10 mg/L.
While this addresses the majority of source and finished drinking waters, there is a possibility
that water matrices could exceed this level. The analyst should monitor all first dimension
chromatograms (Sect. 11.3.4) to confirm that sample matrix does not overload the primary
column capacity and require dilution.
5. SAFETY
5.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely
defined. Each chemical should be treated as a potential health hazard, and exposure to these
chemicals should be minimized. Each laboratory is responsible for maintaining an awareness
of OSHA regulations regarding safe handling of chemicals used in this method. A reference
file of MSDSs should be made available to all personnel involved in the chemical analysis.
Additional references to laboratory safety are available.3"5
6. EQUIPMENT AND SUPPLIES (References to specific brands or catalog numbers are included
for illustration only and do not imply endorsement of the product. This does not preclude the use of
other vendors, supplies or configurations.)
6.1 SAMPLE CONTAINERS - 125-mL brown Nalgene bottles (Fisher Cat. No. 03-313-3C or
equivalent).
6.2 VOLUMETRIC FLASKS - Class A, suggested sizes include 10, 50, 100, 250, 500 and 1000
mL for preparation of standards and eluents.
6.3 GRADUATED CYLINDERS - Suggested sizes include 25 and 1000 mL.
6.4 AUTO PIPETTES - Capable of delivering variable volumes from 1.0 to 2500 uL.
6.5 ANALYTICAL BALANCE - Capable of weighing to the nearest 0.0001 g.
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6.6 DUAL ION CHROMATOGRAPHY SYSTEM WITH SUPPRESSED CONDUCTIVITY
DETECTION (1C) - This section describes the instrument configuration that was used to
collect the data in Section 17. A Dionex Model ICS-3000 Dual system, consisting of a Dual
Pump (DP) module, Eluent Generator (EG) module, Detector/Chromatography (DC) module,
and Autosampler (AS), was used to collect the data presented in this method. Equivalent
systems may be used The 1C system should also have a temperature controlled column
compartment and be capable of operating above room temperature (30 °C) and include dual 1C
pumps and all required accessories, including guard, analytical, and concentrator columns,
detector/chromatography module, dual eluent generators, continuously-regenerated anion trap
columns, compressed gases, autosampler, suppressors, carbonate removal devices (CRD),
dual conductivity detectors, and a computer-based data acquisition and control system.
Additionally, the system must be capable of performing automated, two-dimensional 1C,
including performing inline column concentration and matrix elimination steps as described in
Section 2.1. A schematic diagram of the instrumentation for this 2-D 1C method is shown in
Figure 1. Table 1 provides full details of the instrumental conditions.
6.6.1 DUAL PUMP MODULE - A DP Dual Gradient-Gradient Pumping Module with dual
channel degas devices (Dionex DP, P/N 061712), was used to generate the data for this
method. Equivalent modules may be used. The dual pump system used for method
development was capable of supplying a flow rate of approximately 1.0 mL/min to the
first dimension column and approximately 0.25 mL/min to the second dimension column.
6.6.2 ELUENT GENERATOR MODULE - A dual channel EG Module (Dionex EG, P/N
061714) with dual potassium hydroxide cartridges (EluGen® Cartridge, EGC, P/N
058900) was used to prepare the potassium hydroxide eluent for both the first and second
dimensions of this method. An equivalent eluent generator may be used and/or manually
prepared eluents may also be used provided that adequate resolution, peak shape,
capacity, accuracy, and precision (Sect. 9.2) are obtained. Care must be exercised with
manually prepared hydroxide eluents to prevent formation of carbonate in the eluent from
exposure to the atmosphere, which can dramatically alter the chromatography and affect
sensitivity.
6.6.2.1 CONTINUOUSLY REGENERATED ANION TRAP COLUMNS - 1C eluent
purification columns (Dionex CR-ATC, P/N 060477 or equivalent). Any in-line,
resin-based manual or electrolytic trapping column that provides adequate eluent
purification for ultra trace analysis and performance (Sect. 9.2) may be used. A CR-
ATC device, or equivalent, was used for eluent purification for both the first and
second dimension eluents.
NOTE: For the configuration in Figure 1, the pump and eluent generator modules in
combination must be capable of delivering different isocratic eluent concentrations to
the columns in the first and second dimension. The same requirement applies for
manually prepared eluents with a dual pumping system; the pump system must be
capable of delivering two different, independent isocratic concentrations of eluents to
the first and second dimension columns. In addition, the system should also be
capable of providing a step isocratic eluent concentration change or a controlled
gradient change to both dimensions independently. This allows the first and second
dimension columns to be cycled to a higher eluent concentration in order to clean
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residual matrix components from the columns prior to introduction of the next
sample. This is important to ensure maximum column life and to minimize potential
carryover and/or interferences from one sample to the next.
6.6.3 DETECTOR/CHROMATOGRAPHY MODULE - A DC Module (Dionex DC, P/N
061793 or equivalent) equipped with dual injection valves and capable of maintaining the
columns and the suppressors at 30 °C, and conductivity cell at 35 °C is recommended.
NOTE: For optimal performance of this system, the conductivity cell should be set at a
higher temperature than the analytical columns. For example, if the columns are set at 30
°C, the cell should be set at 35 °C.
6.6.4 FIRST DIMENSION GUARD COLUMN - An 1C column, 4 x 50-mm (Dionex
IonPac®AG19, P/N 062887 or equivalent). Any guard column that provides adequate
protection for the analytical column and does not have an adverse effect on the peak
shape may be used.
6.6.5 FIRST DIMENSION ANALYTICAL COLUMN - An 1C column, 4 x 250 mm (Dionex
IonPac®AS19, P/N 062885 or equivalent). Any analytical column that provides adequate
resolution, peak shape, capacity, accuracy, and precision (Sect. 9.2) may be used. The
separation mechanism for the first dimension analytical column must differ from the
second dimension column in selectivity.
6.6.6 FIRST DIMENSIOIN ANION SUPPRESSOR DEVICE - An 1C eluent suppression
device, 4 mm (Dionex Anion Self-Regenerating Suppressor, ASRS Ultra II, P/N 061561
or equivalent). An equivalent in-line suppression device that effectively suppresses the
conductance of the eluent and converts the analyte to the hydronium form prior to
conductivity detection, as well as provides adequate efficiency, resolution, peak shape,
capacity, accuracy, precision, and a comparable MRL and DL (Section 9.2) may be used.
Adequate baseline stability should be attained as measured by a baseline noise of no more
than 5 nS per minute over the background conductivity. The first dimension suppressor
must be compatible with the first dimension guard and analytical column.
NOTE: The conductivity suppressor was set to perform electrolytic suppression at a
current setting of 161 mA. It was important to operate the suppressor in the external
water mode to reduce baseline noise and achieve optimal method performance.
6.6.7 FIRST DIMENSION CARBONATE REMOVAL DEVICE - An 1C carbonate removal
device, 4 mm (Dionex CRD, P/N 062983 or equivalent). Any in-line carbonate removal
device that effectively removes the carbonate peak from the suppressed eluent stream
prior to conductivity detection and provides adequate efficiency, resolution, peak shape,
capacity, accuracy, and precision for bromate (Section 9.2) may be used. The first
dimension CRD must be compatible with (e.g., 4 mm in this example) the first dimension
guard and analytical column.
6.6.8 FIRST DIMENSION CONDUCTIVITY DETECTOR - A Conductivity detector and
integrated cell (Dionex CD P/N 061716, or equivalent) capable of providing data as
required in Section 9.2. A Standard Bore Temperature Stabilizer (0.010 inch ID, Dionex
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P/N 062561), was also used to equilibrate the temperature of the eluent to that of the first
dimension guard and analytical column. Equivalent stabilizers may be used.
NOTE: The conductivity detector cell temperature should be controlled at a temperature
above that of the analytical column. For method development, the conductivity detector
was set at 35 °C to minimize bubble formation and condensation between analytical
column, suppressor and CRT) and to stabilize the temperature of the detector cell itself.
6.6.9 CONCENTRATOR COLUMN - An 1C trapping column, 5 x 23 mm (Dionex UTAC-
ULP1, P/N 063475 or equivalent). Any concentrator column that provides effective
retention/trapping and release of bromate while providing the resolution, peak shape,
capacity, accuracy, and precision (Sect. 9.2) may be used. The concentrator column
should not release sulfonated leachates that would affect the quantitation of bromate.
6.6.9.1 Alternate concentrator columns are allowed, but prior to their use, they must be
evaluated to determine the first dimension cut window (Sect. 10.2.2). They must be
determined to have sufficient capacity to quantitatively trap bromate in the LFSSM
CCC (Sect. 10.3.3) and should have relatively low backpressure since the
concentrator column is placed as a post-suppressor device.
6.6.10 SECOND DIMENSION GUARD COLUMN - An 1C column, 2 x 50 mm (Dionex
IonPac®AG24, P/N 064151 or equivalent). Any guard column that provides adequate
protection for the analytical column and does not have an adverse effect on the peak
shape may be used.
6.6.11 SECOND DIMENSION ANALYTICAL COLUMN - An 1C column, 2 x 250 mm
(Dionex lonPac® AS24, P/N 064153 or equivalent). Any analytical column that provides
adequate resolution, peak shape, capacity, accuracy, and precision (Sect. 9.2) may be
used. The separation mechanism for the second dimension analytical column must differ
from the first dimension column.
6.6.12 SECOND DIMENSIOIN ANION SUPPRESSOR DEVICE - An 1C eluent suppression
device, 2 mm (Dionex Anion Self-Regenerating Suppressor, ASRS Ultra II, P/N 061562
or equivalent). An equivalent in-line suppression device that effectively suppresses the
conductance of the eluent prior to conductivity detection, and that provides adequate
efficiency, resolution, peak shape, capacity, accuracy, precision, and a comparable MRL
and DL (Section 9.2) may be used. Adequate baseline stability should be attained as
measured by a baseline noise of no more than 5 nS per minute over the background
conductivity. The second-dimension suppressor must be compatible with (e.g., 2 mm in
this example) the second-dimension guard and analytical column.
NOTE: The conductivity suppressor was set to perform electrolytic suppression at a
current setting of 41 mA. It was important to operate the suppressor in the external water
mode to reduce baseline noise and achieve optimal method performance.
6.6.13 SECOND DIMENSION CARBONATE REMOVAL DEVICE - An 1C carbonate
removal device (Dionex CRD, P/N 062986 or equivalent). Any in-line carbonate
removal device that effectively removes the carbonate peak from the suppressed eluent
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stream prior to conductivity detection of the method analyte and provides adequate
efficiency, resolution, peak shape, capacity, accuracy, and precision (Section 9.2) may be
used. The second dimension CRD must be compatible with the second dimension guard
and analytical column.
6.6.14 SECOND DIMENSION CONDUCTIVITY DETECTOR - A Conductivity detector and
integrated cell (Dionex CD P/N 061716, or equivalent) capable of providing data as
required in Section 9.2. A Microbore Temperature Stabilizer (0.005 inch ID, Dionex P/N
062562, or equivalent), was also used to equilibrate the temperature of the eluent to that
of the second dimension guard and analytical column.
NOTE: The conductivity detector cell temperature should be controlled at a temperature
above the analytical column. For method development, the conductivity was set at 35 °C
to minimize bubble formation and condensation between analytical column, suppressor
and CRD and to stabilize the temperature of the detector cell itself.
6.6.15 AUTOSAMPLER MODULE - An AS Autosampler Module with simultaneous injection,
a sample prep option, and a large volume sample needle assembly (Dionex AS P/N
063105) was used to generate data for this method. Any autosampler capable of
automatically injecting up to 1.0 mL of sample may be used.
6.6.16 DATA SYSTEM - An interfaced data system such as Dionex, Chromeleon Version 6.7
(or equivalent) is required to acquire, store, and output conductivity data. The computer
software should have the capability of processing stored conductivity data by recognizing
and integrating a peak within a given retention time window. The software should be
capable of constructing linear regressions or quadratic calibration curves, and calculating
analyte concentrations using the calibrations.
7. REAGENTS AND STANDARDS
7.1 REAGENTS - Reagent grade or better chemicals should be used in all tests. Unless
otherwise indicated, it is intended that all reagents will conform to the specifications of the
Committee on Analytical Reagents of the American Chemical Society (ACS), where such
specifications are available. Other grades may be used, provided it is first determined that
the reagent is of sufficiently high purity to permit its use without lessening the quality of the
determination.
7.1.1 REAGENT WATER (RW) - Purified water that does not contain any measurable
quantity of the target analyte or interfering compounds at or above 1/3 the bromate MRL.
The purity of the water required for this method cannot be over emphasized. The reagent
water used during method development was purified from tap water using a Millipore
ELIX-3 followed by a Millipore Gradient A10 system. The water should contain no
particles larger than 0.20 microns.
7.1.2 ELUENT SOLUTIONS - Two hydroxide eluent concentrations were used to collect the
data in Section 17. A potassium hydroxide eluent concentration of 10 mM was used for
the first dimension matrix elimination separation on the AS 19 column, and 10 mM for
the second dimension separation on the AS24 column. In addition, a hydroxide eluent
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concentration of 65 mM was delivered to the first dimension column after the bromate
heart-cut step was completed to ensure the column was properly cleaned prior to the next
analysis. As well, the second dimension AS24 column was cleaned with 65 mM
hydroxide after the elution of bromate and equilibrated with 10 mM hydroxide prior to
injection of the next sample. These eluents were automatically prepared using
electrolytic eluent generation with the ICS-3000 EG Eluent Generator and EluGen
potassium hydroxide cartridges (Sect 6.6.2). They may also be manually prepared (Sect.
6.6.2) if adequate precautions are used to prevent carbonate formation from exposure to
laboratory air.
7.1.2 BROMATE STANDARD - (BrO3~, CASRN 15541-45-4) - Ultra Scientific Cat. No.
ULICC-010 or equivalent.
7.1.3 SODIUM BICARBONATE - (NaHCO3, CASRN 497-19-8) - Fluka Cat. No. 71627 or
equivalent.
7.1.4 SODIUM BROMATE - (NaBrO3, CASRN 7789-38-0) - EM Science Cat. No. SX0385-1
or equivalent.
7.1.5 SODIUM CHLORIDE - (NaCl, CASRN 7647-14-5) - Fisher Scientific Cat. No. S-271
or equivalent.
7.1.6 SODIUM NITRATE - (NaNO3, CASRN 7631-99-4) - Fisher Scientific Cat. No. S343-
500) or equivalent.
7.1.7 SODIUM PHOSPHATE, DIBASIC, ANHYDROUS - (Na2HPO4, CASRN 10140-65-5)
JT. Baker Cat. No. 4062-1 or equivalent.
7.1.8 SODIUM SULFATE - (Na2SO4, CASRN 7757-82-6) - Fluka Cat. No. 71959 or
equivalent.
7.1.9 ETHYLENEDIAMINE (EDA) PRESERVATION SOLUTION (10 mg/mL) - Add 2.8
mL of ethylenediamine (99%) (CASRN 19559-59-2) to a 250-mL volumetric flask and
dilute to volume with reagent water.
7.2 STANDARD SOLUTIONS - When a compound purity is assayed to be 96 percent or greater,
the weight can be used without correction to calculate the concentration of the stock standard.
Solution concentrations listed in this section were used to develop this method and are
included only as an example. Although estimated stability times for standard solutions are
suggested in the following subsections, laboratories should use standard QC practices to
determine when their standards need to be replaced.
7.2.1 BROMATE STANDARD SOLUTIONS - Obtain the analyte as a solid standard or as a
commercially prepared standard from a reputable standard manufacturer. Prepare the
bromate stock and dilution solutions as described below.
7.2.1.1 BROMATE STOCK STANDARD SOLUTION (SSS) (1000 mg/L BrO3') -
Preparation of this solution is accomplished using a solid NaBrO3 standard. Weigh
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out 118.0 mg of NaBrO3 into a 100-mL volumetric flask and dilute to volume with
reagent water. When stored in opaque, plastic storage bottles, the resulting stock
solution may be stable for up to one year.
7.2.1.2 BROMATE PRIMARY DILUTION SOLUTION (PDS) (10.0 mg/L BrO3") - Prepare
the Bromate PDS by adding 1.0 mL of the Bromate SSS to a 100-mL volumetric flask
and dilute to volume with reagent water. This solution is used to prepare the Bromate
Secondary Dilution Standard Solution, the Bromate Fortification Solutions and the
Calibration Solutions below. When stored in opaque, plastic storage bottles, the
resulting solution is stable for at least one month.
7.2.1.3 BROMATE SECONDARY DILUTION SOLUTION (SDS) (1.0 mg/L BrO3') -
Prepare the 1.0 mg/L Bromate SDS by adding 10.0 mL of the Bromate PDS to a 100-
mL volumetric flask and diluting to volume with reagent water. This solution is used
to prepare the Bromate Fortification Solutions, CAL and CCC Standards listed below.
When stored in opaque, plastic storage bottles, the resulting solution is stable for at
least one month.
7.2.1.4 BROMATE FORTIFICATION SOLUTIONS (BFS) (50, 200 and 500 |ig/L BrO3") -
The Bromate Fortification Solutions are prepared by dilution of the Bromate SDS and
are used to fortify the Laboratory Fortified Blank (LFB), the Laboratory Fortified
Sample Matrix (LFSM), the Laboratory Fortified Sample Matrix Duplicate (LFSMD)
and the Laboratory Fortified Synthetic Sample Matrix (LFSSM) with bromate. It is
recommended that multiple concentrations be prepared so that the fortification levels
can be rotated or adjusted to the concentration of the target analyte in the native
samples. When stored in opaque, plastic storage bottles, the resulting solutions are
stable for at least one month.
7.2.2 LABORATORY SYNTHETIC SAMPLE MATRIX (LSSM) - Prepare a LSSM that
contains the common anions chloride, sulfate and bicarbonate at 100 mg/L, and
phosphate as phosphorus and nitrate as nitrogen at 10 mg/L as follows.
7.2.2.1 Weigh out 276 mg of NaHCO3, 296 mg of Na2SO4, 330 mg of NaCl, 91.7 mg of
Na2HPO4 and 121 mg of NaNO3. Add these to a 2000-mL volumetric flask using a
funnel and dilute to volume using reagent water.
7.3 CALIBRATION STANDARDS (CAL) - Prepare a calibration curve from dilutions of the
Bromate PDS and the Bromate SDS using a minimum of five Calibration Standards, which
span the concentration range of interest. The lowest CAL standard must be at or below the
MRL. An example of the dilutions used to prepare the CAL standards used to collect the data
in Section 17 are shown in the Table below.
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CALand CCC
Levels
CAL1
CAL 2
CAL 3
CAL 4
CAL 5
CAL 6
CAL 7
CAL 8
Vol. of
Br03
PDS
(HL)
30
50
100
150
Vol. of
Br03
SDS
(HL)
15
25
50
100
Final
Vol. of
Std.
(mL)
100
100
100
100
100
100
100
100
Final
Cone, of
Br03
(HS/L)
0.15
0.25
0.50
1.00
3.00
5.00
10.0
15.0
7.4 CONTINUING CALIBRATION CHECK STANDARDS (CCC) - Prepare the CCC
standards from dilutions of the Bromate PDS and the Bromate SDS at three concentrations
representing the low, mid and high points of the calibration curve. The low-level CCC should
be at or below the MRL.
7.5 LABORATORY FORTIFIED SYNTHETIC SAMPLE MATRIX CCC STANDARD - In
order to ensure that the first dimension cut window is functioning properly during each
analysis batch, a CCC is also prepared in the laboratory synthetic sample matrix. This
solution is termed the Laboratory Fortified Synthetic Sample Matrix (LFSSM) CCC and is
analyzed following the last high-level CCC during each Analysis Batch.
8. SAMPLE COLLECTION, PRESERVATION, AND STORAGE
8.1 SAMPLE COLLECTION
8.1.1 Grab samples must be collected in plastic or glass containers accordance with
conventional sampling practices. 6
8.1.2 When sampling from a cold water tap, open the tap and allow the system to flush until the
water temperature has stabilized (usually approximately 3 to 5 minutes). Collect a
representative sample from the flowing system using a beaker of appropriate size. Use
this bulk sample to generate individual samples as needed. A volume of approximately
20-mL is required for each individual sample.
8.1.3 When sampling from an open body of water, fill a beaker with water sampled from a
representative area. Use this bulk sample to generate individual samples as needed. A
volume of approximately 20-mL of sample is required for each individual sample.
8.1.4 Samples must be dechlorinated at the time of collection by adding EDA so that the final
concentration in the sample container is 50 mg/L. For a 20 mL sample, this would
require 100 uL of the EDA Preservation Solution (Sect. 7.1.9).
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8.2 SAMPLE SHIPMENT AND STORAGE - Field samples must be chilled during shipment and
must not exceed 10 °C during the first 48 hours after collection. Field samples should be
confirmed to be at or below 10 °C when they are received at the laboratory. Field samples
stored in the lab must be held at or below 6 °C until analysis.
8.3 SAMPLE HOLDING TIMES - Field samples that are collected and stored as described in
Sections 8.1 and 8.2 may be held for up to 28 days.
9. QUALITY CONTROL
9.1. Quality Control requirements include the Initial Demonstration of Capability (IDC) and
ongoing QC requirements that must be met when preparing and analyzing field samples. This
section describes each QC parameter, its required frequency, and the performance criteria that
must be met in order to meet EPA data quality objectives. The QC criteria discussed in the
following sections are summarized in Section 17, Tables 4 and 5. These QC requirements are
considered the minimum acceptable QC criteria. Laboratories are encouraged to institute
additional QC practices to meet their specific needs.
9.2 INITIAL DEMONSTRATION OF CAPABILITY (IDC) - The IDC must be successfully
performed prior to analyzing any field samples. Prior to conducting the IDC, the analyst must
first meet the calibration requirements outlined in Section 10. Requirements for the IDC are
described in the following sections and are summarized in Table 4.
9.2.1 DEMONSTRATION OF LOW SYSTEM BACKGROUND - Analyze a Laboratory
Reagent Blank (LRB) processed through all sample collection steps outlined in Section
8.1. Confirm that the LRB is reasonably free of contamination (< 1/3 the MRL) and that
the criteria in Section 9.3.1 are met.
NOTE: It is a good laboratory practice to include a blank in the calibration of any
instrument. The method should also be checked for carry-over by analyzing a RW blank
immediately following the highest CAL standard. If this RW sample does not meet the
criteria outlined in Section 9.3.1 then carry-over is present and should be identified and
eliminated.
9.2.2 DEMONSTRATION OF PRECISION - Prepare and analyze 7 replicate LFBs and
LFSSMs fortified near the midrange of the initial calibration curve. The percent relative
standard deviation (%RSD) of the results of the replicate analyses must be < 20 percent.
_ Standard Deviation of Measured Concentrations
/o RSD — X100
Average Concentration
9.2.3 DEMONSTRATION OF ACCURACY - Using the same set of replicate data generated
for Section 9.2.2, calculate average recovery. The average recovery of the replicate
values must be within ± 20 percent of the true value.
„._, Average Measured Concentration n^
% Recovery = x 100
Fortified Concentration
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9.2.4 MINIMUM REPORTING LEVEL (MRL) CONFIRMATION - Establish a target
concentration for the MRL based on the intended use of the method. The lowest
calibration standard used to establish the initial calibration (as well as the low-level CCC)
must be at or below the concentration of the MRL. Establishing the MRL concentration
too low may cause repeated failure of ongoing QC requirements. Confirm or validate the
MRL following the procedure outlined below.
9.2.4.1 Fortify and analyze seven replicate LFB at or below the proposed MRL
concentration. Calculate the mean (Mean) and standard deviation (S) for these
replicates. Determine the Half Range for the Prediction Interval of Results (HRpiR)
using the equation below.
HRpm = 3.963S
where S is the standard deviation, and 3.963 is a constant value for seven
replicates.1
9.2.4.2 Confirm that the upper and lower limits for the Prediction Interval of Results (PIR =
Mean +_ HRpjR) meet the upper and lower recovery limits as shown below.
The Upper PIR Limit must be < 150 percent recovery.
Mean + HRP1R
FortifiedConcentration
The Lower PIR Limit must be > 50 percent recovery.
Mean - HRPJP
— —— — x 100> 50%
FortijiedC oncentration
9.2.4.3 The MRL is validated if both the Upper and Lower PIR Limits meet the criteria
described above (Sect. 9.2.4.2). If these criteria are not met, the MRL has been set
too low and must be determined again at a higher concentration.
9.2.5 QUALITY CONTROL SAMPLE (QCS) - Analyze a mid-level Quality Control Sample
(Sect. 9.3.7) to confirm the accuracy of the calibration curve fit.
9.2.6 DETECTION LIMIT DETERMINATION (DL) (optional) - While DL determination is
not a specific requirement of this method, it may be required by various regulatory
bodies associated with compliance monitoring. It is the responsibility of the laboratory
to determine ifDL determination is required based upon the intended use of the data.
Analyses for this procedure should be done over at least 3 days. Prepare and analyze at
least 7 replicate fortified LFBs. Use the solutions described in Section 7.2.1.4 to fortify
at a concentration estimated to be near the DL. This fortification concentration may be
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estimated by selecting a concentration at 2-5 times the noise level. Analyze the seven
replicates through all steps of Section 11.
NOTE: If an MRL confirmation data set meets these requirements, a DL may be
calculated from the MRL confirmation data, and no additional analyses are necessary.
Calculate the DL using the following equation:
DL = St(n- 1, 1 - alpha = 0.99)
where:
t( n -1,1 - alpha = o.99) = Student's t value for the 99% confidence level with n-1
degrees of freedom
n = number of replicates
S = standard deviation of replicate analyses.
NOTE: Do not subtract blank values when performing DL calculations.
9.3 ONGOING QC REQUIREMENTS - This section describes the ongoing QC criteria that
must be followed when processing and analyzing field samples. Table 5 summarizes these
requirements.
9.3.1 LABORATORY REAGENT BLANK (LRB) - A LRB is analyzed during the IDC and is
required with each Analysis Batch (Sect. 3.1) to confirm that potential background
contaminants are not interfering with the identification or quantitation of bromate. If
within the retention time window of any analyte, the LRB produces a peak that would
prevent the determination of bromate, determine the source of contamination and
eliminate the interference before processing samples. Background from target analytes or
contaminants that interfere with the measurement of target analytes must be < 1/3 the
MRL. If the target analytes are detected in the LRB at concentrations equal to or greater
than this level, then all data for the problem analyte(s) must be considered invalid for all
samples which yielded a positive result.
NOTE: Although quantitative data below the MRL may not be accurate enough for data
reporting, such data are useful in determining the magnitude of a background
interference. Therefore, blank contamination levels may be estimated by extrapolation,
when the concentration is below the MRL.
9.3.2 CONTINUING CALIBRATION CHECK STANDARDS (CCC) - CCC standards are
analyzed at the beginning of each Analysis Batch, after every ten field samples, and at the
end of the Analysis Batch. See Section 10.3 and Table 5 for concentration requirements
and acceptance criteria.
9.3.3 LABORATORY FORTIFIED SYNTHETIC SAMPLE MATRIX CCC STANDARD
(LFSSM CCC) - A CCC standard prepared in the LSSM at the same concentration as the
high-level CCC Standard should be analyzed at the end of each Analysis Batch. The
LFSSM CCC is used to ensure the integrity of the sample pre-concentration/matrix
elimination step and the chromatographic separation of bromate from other interfering
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anionic species in very high ionic matrices. See Section 10.3.3. and Table 5 for
concentration requirements and acceptance criteria.
9.3.4 LABORATORY FORTIFIED BLANK (LFB) - A LFB is required with each Analysis
Batch. In successive analysis batches, the LFB fortification level must be rotated
between low, medium, and high. The low concentration LFB must be at or below the
MRL. Results of LFBs fortified at < MRL must be within 50-150% of the true value.
Results of LFB analyses from all other concentrations must be 80-120% of the true value.
If the LFB results do not meet these criteria, then all data for bromate must be considered
invalid for all samples in the Analysis Batch.
9.3.5 LABORATORY FORTIFIED SAMPLE MATRIX (LFSM) - Analysis of a LFSM (Sect.
3.8) is required in each Analysis Batch. The LFSM is processed and analyzed exactly
like a traditional sample, and its purpose is to determine whether the sample matrix
contributes bias to the analytical results. The native concentration of the analyte in the
sample matrix must be determined in a separate aliquot and the measured value in the
LFSM corrected for the native concentration. If a variety of different sample matrices are
analyzed regularly, for example drinking water from groundwater and surface water
sources, performance data should be collected for each source.
9.3.5.1 Within each Analysis Batch, a minimum of one field sample must be fortified as an
LFSM for every 20 field samples analyzed. The LFSM is prepared by spiking a field
sample with an appropriate amount of the Bromate Fortification Solutions (Sect.
7.2. 1 .4). The fortification should be delivered in the smallest volume possible to
minimize dilution of the sample. Select a fortification concentration that is equal to
or greater than the native concentration, if known. Use historical data and rotate
through the designated concentrations when selecting a fortifying concentration.
Calculate the percent recovery (%REC) using the equation
C
A = measured concentration in the fortified sample
B = measured concentration in the unfortified sample
C = fortification concentration
9.3.5.2 Recoveries for samples fortified at concentrations near or at the MRL (within a factor
of two times the MRL concentration) should be 50-150%. Recoveries for samples
fortified at all other concentrations should be 80-120%. If the accuracy for any
analyte falls outside the designated range, and the laboratory performance for that
analyte is shown to be in control in the CCCs and the LFSSM CCC, the recovery is
judged to be matrix biased. The result for that analyte in the unfortified sample is
labeled "suspect/matrix" to inform the data user that the results are suspect due to
matrix effects.
9.3.5.2.1 Field samples that have a native bromate concentrations above the DL but
below the MRL and are fortified at concentrations at or near the lowest
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calibration standard should be corrected for the native levels in order to obtain
meaningful percent recovery values. This example and the LRB (Sect. 9.3.1)
are the only permitted use of analyte results below the MRL.
9.3.6 LABORATORY DUPLICATE OR LABORATORY FORTIFIED SAMPLE MATRIX
DUPLICATE (LD or LFSMD) - Within each Analysis Batch, a minimum of one
Laboratory Duplicate (LD) or Laboratory Fortified Sample Matrix Duplicate (LFSMD)
must be analyzed. Laboratory Duplicates check the precision associated with laboratory
procedures. If target analytes are not routinely observed in field samples, a LFSMD
should be analyzed rather than a LD.
9.3.6.1 Calculate the relative percent difference (RPD) for duplicate measurements (LDi and
LD2) using the equation
LD.-LD,
RPD =—! l- ^— xlOO
(LD1+LD2)/2
9.3.6.2 RPDs for Laboratory Duplicates should be < 20%. Greater variability may be
observed when Laboratory Duplicates have analyte concentrations that are within a
factor of 2 of the MRL. At these concentrations Laboratory Duplicates should have
RPDs that are < 50 percent. If the RPD of any analyte falls outside the designated
range, and the laboratory performance for that analyte is shown to be in control in the
CCCs and LFSSM CCC, the recovery is judged to be matrix influenced. The result
for that analyte in the unfortified field sample is labeled "suspect/matrix" to inform
the data user that the results are suspect due to matrix effects.
9.3.6.3 If a LFSMD is analyzed instead of a Laboratory Duplicate, calculate the relative
percent difference (RPD) for duplicate LFSMs (LFSM and LFSMD) using the
equation.
\LFSM-LFSMD
RPD = -^ r—xlOO
(LFSM+LFSMD)/2
9.3.6.4 RPDs for duplicate LFSMs must be < 20%. Greater variability may be observed
when LFSMs are fortified at analyte concentrations that are within a factor of 2 of the
MRL. LFSMs fortified at these concentrations must have RPDs that are < 50%. If
the RPD of any analyte falls outside the designated range, and the laboratory
performance for that analyte is shown to be in control in the CCCs and LFSSM CCC,
the precision is judged to be matrix influenced. The result for that analyte in the
unfortified field sample is labeled "suspect/matrix" to inform the data user that the
results are suspect due to matrix effects.
9.3.7 QUALITY CONTROL SAMPLES (QCS) -A QCS must be evaluated as part of the IDC
(Sect. 9.2.5) and each time new PDS solutions are prepared. If standards are prepared
infrequently, analyze a QCS at least quarterly. The QCS should be fortified near the
midpoint of the calibration range and analyzed as a CCC. The acceptance criteria for the
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QCS is the same as for the mid- and high-level CCCs (Section 10.3). If measured analyte
concentrations are not of acceptable accuracy, check the entire analytical procedure to
locate and correct the problem.
9.4 METHOD MODIFICATION QC REQUIREMENTS - The analyst is permitted to modify
the separation technique, 1C columns, concentrator column and mobile phase composition.
However, any modifications must maintain the basic chromatographic elements of this new
technique (Sect 1.6).
9.4.1 Each time method modifications are made, the analyst must first redetermine the cut
window following Section 10.2.2 using bromate solutions fortified into RW and the
LSSM (Sect. 7.2.2) and then reestablish an acceptable initial calibration (Sect. 10.2.3).
Alternate configurations may require modification of this technique. If alternate
procedures are used, the analyst must still employ the LSSM and RW matrices to set the
start and stop times of the cut windows.
9.4.2 Repeat the procedures of the IDC (Sect. 9.2) and verify that all Ongoing QC criteria can
be met for the proposed method modification (Sect. 9.3).
9.4.3 The analyst is also required to evaluate method performance for the proposed method
modifications in real matrices that span the range of waters that the laboratory analyzes.
This additional step is required because modifications that perform acceptably during the
IDC, which is conducted in reagent water and the LSSM, can fail ongoing method QC
requirements in real matrices due to common method interferences. If, for example, the
laboratory analyzes finished waters from both surface and groundwater municipalities,
this requirement can be accomplished by assessing precision and accuracy (Sects. 9.2.2
and 9.2.3) in a surface water with moderate to high total organic carbon ( e.g., 2 mg/L or
greater) and a hard groundwater (e.g., 250 mg/L or greater).
9.4.4 The results of Sections 9.4.1 - 9.4.3 must be appropriately documented by the analyst and
should be independently assessed by the laboratory's QA officer prior to its application to
field samples.
9.4.4.1 When implementing method modifications, it is the responsibility of the laboratory to
closely review the results of Ongoing QC, and in particular, the results associated
with the LFSM (Sect. 9.3.5), the LFSMD (Sect. 9.3.6) and the LFSSM CCCs (Sect.
9.3.3). If repeated failures are noted, the modification must be abandoned.
10. CALIBRATION AND STANDARDIZATION
10.1 Demonstration and documentation of acceptable initial calibration for bromate is required
prior to conducting the IDC and before any field samples are analyzed. If the initial
calibration is successful, continuing calibration check standards are required at the beginning
and end of each Analysis Batch, as well as after every tenth field sample.
10.2 INITIAL CALIBRATION - The initial calibration must be established prior to conducting
the IDC (Section 9.2) and may be reestablished prior to analyzing field samples. However, it
is permissible to verify the calibration with daily CCCs. Calibration should be performed
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using peak areas and the external standard technique. Calibration using peak heights is not
permitted.
10.2.1 INSTRUMENT CONDITIONS - Establish proper operating conditions. Operating
conditions used during method development are described in Section 17 Table 1.
Conditions different from those described may be used if the IDC QC criteria in Section
9.2 are met. The procedure used to establish the first dimension cut window is provided
in Section 10.2.2 below.
NOTE: For 2D-IC techniques, increased method sensitivity is achieved by injecting
larger volumes. Increased injection volume must be carefully evaluated for each set of
instrument conditions. For the conditions and equipment reported in this method, the
maximum recommended injection volume is 1.0 mL. This is because bromate elutes just
prior to chloride on the first dimension column. Injection volumes above 1.0 mL may
cause potential chloride interference.
10.2.2 FIRST DIMENSION CUT WINDOW DETERMINATION - Since a large volume (1.0
mL) is injected onto the first dimension column, the affect of high ionic strength matrices
on the bromate retention time requires careful consideration. Determination of the cut
window is the first step in separating bromate from other interfering anionic matrix
species. Setting of the cut window in the first dimension must include evaluation of the
retention time for bromate in both RW and the LSSM.
NOTE: The procedure described below is applicable to the equipment configuration
listed in Section 6. However, since acceptable modifications to this method require
heart-cutting of bromate, the trapping of bromate on a concentrator column, and the
subsequent separation and quantitation on a dissimilar analytical column, all modified
versions of this procedure require the proper determination of the cut window. Similar
techniques must therefore be developed and used by analysts using modified methods.
10.2.2.1 DETERMINING THE START TIME OF THE CUT WINDOW - Inject an
aliquot (1.0 mL) of a 15 ug/L bromate fortification in the LSSM (without injection
valve #2 on system #2 being activated) to determine the start time for the cut window.
The start time for the cut window in the first dimension should be set at 0.50 minutes
prior to the start of the bromate elution in the LSSM.
NOTE: The bromate in the LSSM may not appear as a distinct peak, but rather as a
broad, smeared peak on the first dimension column. However, a distinct rise in
baseline is evident when bromate starts to elute from the column (see Figure 3).
10.2.2.2 DETERMINING THE STOP TIME OF THE CUT WINDOW - The stop time
for the cut window is established using reagent water. Inject an aliquot (1.0 mL) of a
15 ug/L bromate standard in RW and determine when bromate is completely eluted
off the first dimension column. The stop time for the cut window in the first
dimension should be set at 0.20 minutes after the bromate peak in RW returns to
baseline.
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NOTE: Since the stop time for the cut window is also the time at which injection
valve #2 on system #2 is switched to the inject position, the elution of bromate must
be completed at least 15 seconds before injection valve #2 is switched into the inject
position when this instrument configuration is used (see Figure 3).
10.2.3 CALIBRATION - Prepare a set of at least five CAL standards as described in Section
7.3. The lowest concentration CAL standard must be at or below the MRL. TheMRL
must be confirmed using the procedure outlined in Section 9.2.4, after establishing the
initial calibration. Calibrate the conductivity detector using the external standard tech-
nique. Calibration curves may be generated using the 1C data system through the use of
first (linear) or second (quadratic) order calibration curves. A quadratic fit is
recommended for this method. Concentration-based weighting may also be used;
however, if this approach is chosen the analyst must confirm this fit does not introduce
bias in the higher concentration region of the curve.
10.2.3.1 CALIBRATION ACCEPTANCE CRITERIA - The validation of the calibration
is determined by calculating the concentration of the analyte from each of the
analyses used to generate the calibration curve. At least one CAL standard must be at
or below the MRL. This calibration point should calculate to be 50 to 150 percent of
its true value. All other higher concentration calibration points should calculate to be
80 to 120 percent of their true values. If these criteria cannot be met, the analyst will
have difficulty meeting ongoing QC criteria. In this case, corrective action should be
taken to reanalyze the calibration standards, restrict the range of calibration, or select
an alternate method of calibration.
10.3 CONTINUING CALIBRATION CHECK (CCC) STANDARDS - The CCCs verify the
calibration at the beginning and end of each group of analyses, as well as after every 10th
field sample. The LRBs, LFBs, LFSSMs, LFSMs, LFSMDs, and CCCs are not counted as
field samples. The beginning CCC for each Analysis Batch must be at or below the MRL in
order to verify instrument sensitivity and the accuracy of the calibration curve prior to the
analysis of any field samples. Subsequent CCCs should alternate between a medium and
high concentration.
10.3.1 Inject an aliquot of the CCC standards and analyze with the same conditions used during
the initial calibration.
10.3.2 Calculate the concentration of the analyte in the CCC standards. The calculated amount
for the analyte for mid and high level CCCs must be within ± 20 percent of the true
value. The calculated analyte amount for the lowest CCC level must be within ± 50
percent of the true value. If these conditions do not exist, then all data for the analyte
must be considered invalid, and remedial action (Sect. 10.3.4) must be taken which may
require recalibration. Any results from field samples that have been analyzed since the
last acceptable calibration verification are invalid.
10.3.2.1 The analyst should carefully review all first-dimension chromatograms for the
CCCs to ensure that the entire chromatographic peak elutes within the cut window. If
this is not the case, the analyst should redetermine the cut window as per Section
10.2.2.
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10.3.3 LABORATORY FORTIFIED SYNTHETIC SAMPLE MATRIX CCC STANDARD
(LFSSM CCC) - As chromatographic columns age, column performance can deteriorate.
This deterioration will typically result in a decreased retention time for bromate, which
can affect the bromate retention time in high inorganic matrices. A LFSSM CCC must be
analyzed daily in each Analysis Batch at a concentration equal to the high-level CCC to
ensure that the first dimension cut window is functioning properly for high inorganic
strength waters. The QC acceptance criteria for the LFSSM CCC is the same as for the
high-level CCCs (within ± 20%). If these conditions do not exist, then all data for the
analyte must be considered invalid, and remedial action should be taken which may
require the reestablishing the cut window (Sect. 10.2.2) and recalibration.
10.3.3.1 The analyst should carefully review all first-dimension chromatograms for the
LFSSM CCC to ensure that the entire chromatographic peak elutes within the cut
window. If this is not the case, the analyst should redetermine the cut window as per
Section 10.2.2.
10.3.4 REMEDIAL ACTION - Failure to meet CCC or LFSSM CCC QC performance criteria
requires remedial action. Maintenance such as confirming the integrity of the trapping
efficiency of the concentrator column and matrix elimination step and/or regenerating or
replacing the 1C guard and analytical columns require returning to the initial calibration
step (Sect. 10.2).
11. PROCEDURE
11.1 Important aspects of this analytical procedure include proper field sample collection,
preservation and storage (Sect. 8), ensuring that the instrument is properly calibrated (Sect.
10.2) and that all required QC are met (Sect. 9) during each Analysis Batch. This section
describes the procedures for field sample preparation and analysis. If alternative
instrumentation and/or columns to those listed in this method are used, the procedure
outlined in Sections 9.2 must be followed prior to analyzing field samples.
11.2 SAMPLE PREPARATION
11.2.1 Collect and store field samples as described in Section 8.
11.3 SAMPLE ANALYSIS
11.3.1 Establish the instrument operating conditions as described in Table 1 of Section 17.
Confirm that the analyte retention times for the calibration standards are stable.
11.3.2 Establish a valid initial calibration following the procedures outlined in Section 10.2 or
confirm that the calibration is still valid by running a low-level CCC as described in
Section 10.3. If establishing an initial calibration for the first time, complete the IDC as
described in Section 9.2.
302.0-23
-------
11.3.3 Analyze field and QC samples at their required frequencies using the same conditions
used to collect the initial calibration. Table 6 shows an acceptable analytical sequence
that contains all method-required QC samples.
11.3.4 COMPOUND IDENTIFICATION - Establish an appropriate retention time window for
bromate elution from the second dimension column in order to identify it in QC and field
sample chromatograms.
11.3.4.1 Since the ionic strength of drinking water matrices may vary considerably, the
cut window (Sect. 10.2.2) for bromate in the first dimension must be set wide
enough to account for the variability in the ionic strength of the drinking
water matrices. A window of approximately 2 minutes (using a 1.0 mL injection
volume) was been found to be acceptable for the system used during method
development. If the cut window is not set properly, analyte recoveries may be
reduced without affecting the second-dimension retention times.
11.3.4.2 Retention times in the second dimension should be very stable as long as the first-
dimension heart-cut window has been set properly (Sect. 10.2.2). This is because
a majority of the common anions, which alter the ionic strength of field samples
causing sample-to-sample variation in 1C retention time, are eliminated during the
heart-cut procedure. Retention times measured for bromate in RW and for the
LFSSM were essentially identical during method development.
11.3.4.3 The QC requirements for each analysis batch include a first-dimension printout of
the final CCC and the high level LFSSM CCC chromatograms to ensure the
heart-cut window is functioning properly. The analyst should also review all
first-dimension chromatograms to ensure acceptable chromatographic
performance within the first-dimension cut window. For example, if a sample had
a much higher conductivity (significantly above the LFSSM) caused by either
very high levels of interfering anions or bromate, the first-dimension cut window
would be overwhelmed. In such an instance, the sample should be diluted and
reanalyzed.
11.3.4.4 High ionic strength matrices have the potential to cause an increase in background
conductivity and severe tailing as the other anions elute from the first dimension
column and cause the bromate retention time to decrease.
11.3.5 EXCEEDING CALIBRATION RANGE - The analyst must not extrapolate beyond the
established calibration range. If an analyte result exceeds the range of the initial
calibration curve, the field sample may be diluted with reagent water and the diluted field
sample re-injected. Incorporate the dilution factor into final concentration calculations.
The dilution will also affect the bromate MRL.
302.0-24
-------
12. DATA ANALYSIS AND CALCULATIONS
12.1 Identify the analyte present in the field and QC Samples as described in Section 11.3.4.
12.2 Calculate the bromate concentrations using the multi-point calibration established in Section
10.2. Quantify only those values that fall between the MRL and the highest calibration
standard. Field samples with target analyte responses that exceed the highest calibration
standard require dilution and reanalysis (Sect. 11.3.5).
12.2.1 As noted in Section 9.3.5.2.1, it may be necessary to extrapolate below the MRL to
estimate contaminants in LRBs and to correct for native levels of bromate below the
MRL when field samples are fortified at or near the MRL. These are the only permitted
use of analyte results below the MRL.
12.3 Calculations must utilize all available digits of precision, but final reported concentrations
should be rounded to an appropriate number of significant figures (one digit of uncertainty),
typically two, and not more than three significant figures.
12.4 Prior to reporting data, the laboratory is responsible for assuring that QC requirements have
been met or that any appropriate qualifier is documented.
13. METHOD PERFORMANCE
13.1 PRECISION, ACCURACY AND DETECTION LIMITS - Tables for these data are
presented in Section 17. The LCMRL for bromate is presented in Table 2 and was calculated
using a procedure described elsewhere.1 The DL data is also reported in Table 2. Single
laboratory precision and accuracy data are presented in Table 3.
13.2 Figure 3 is a representation of both the first and second dimension chromatograms for a 15
ug/L bromate fortification in the LSSM and Figure 4 shows similar chromatograms for a 0.50
Hg/L bromate fortification to a municipal ground water, disinfected with chlorine.
14. POLLUTION PREVENTION
14.1 For information about pollution prevention that may be applicable to laboratory operations,
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, or on-line at:
http://www.ups.edu/community/storeroom/Chemical Wastes/wastearticles.htm.
15. WASTE MANAGEMENT
15.1 The analytical procedures described in this method generate relatively small amounts of waste
since only small amounts of reagents are used. The matrices of concern are finished drinking
water or source water. However, the Agency requires that laboratory waste management
practices be conducted consistent with all applicable rules and regulations, and that
laboratories protect the air, water, and land by minimizing and controlling all releases from
302.0-25
-------
fume hoods and bench operations. Also, compliance is required with any sewage discharge
permits and regulations, particularly the hazardous waste identification rules and land disposal
restrictions. For further information on waste management, see the publications of the
American Chemical Society's Laboratory Environment, Health & Safety Task Force on the
Internet at http://membership.acs.Org/c/ccs/publications.htm. Or see "Laboratory Waste
Minimization and Pollution Prevention," Copyright © 1996 Battelle Seattle Research Center,
which can be found at http://www.p2pays.org/ref/01 /text/00779/index2.htm.
16. REFERENCES
1. Winslow, S. D.; Pepich, B. V.; Martin, J. I; Hallberg, G. R.; Munch, D. I; Frebis, C. P.;
Hedrick, E. J.; Krop, R. A. Statistical Procedures for Determination and Verification of
Minimum Reporting Levels for Drinking Water Methods. Environ. Sci. & Technol. 2006, 40,
281-288.
2. Glaser, J.A.; Foerst, D.L.; McKee, G. D.; Quave, S. A.; Budde, W. L. Trace Analyses for
Wastewaters, Environ. Sci. & Technol. 1981, 15, 1426-1435.
3. Safety in Academic Chemistry Laboratories; American Chemical Society Publication,
Committee on Chemical Safety, 7th Edition: Washington, D.C., 2003.
4. Occupational Exposures to Hazardous Chemical in Laboratories; 29 CFR 1910.1450,
Occupational Safety and Health Administration, 1990.
5. "Guidelines, Recommendations, and Regulations for Handling Antineoplastic Agents", Center
for Disease Control, National Institute for Occupational Safety and Health,
http://www.cdc.gov/niosh/topics/antineoplastic/pubs.htmltfb
6. Standard Practice for Sampling Water from Closed Conduits; ASTM Annual Book of Standards,
Section 11, Volume 11.01, D3370-82, American Society for Testing and Materials: Philadelphia,
PA, 2008.
302.0-26
-------
17.0 TABLES, DIAGRAMS, FLOWCHARTS, AND VALIDATION DATA
TABLE 1. INSTRUMENTAL CONDITIONS USED DURING METHOD DEVELOPMENT
Standard Conditions and Equipment for First Dimension Analyses a'b:
Ion Chromatograph:
Sample loop:
Load Volume:
Eluent Generator:
Eluent Flow:
Autosampler:
Columns :
Typical System Back-pressure:
Conductivity Suppressor:
Chromatography Module
Detector:
Total analysis time:
Dionex ICS-3000 Dual System
1.0 mL
1000 |iL
Dionex ICS-3000 EG Eluent Generator Module (P/N 061714), with
dual channel EluGen Cartridges (P/N 058900), isocratic 10 mM
potassium hydroxide step changed or ramped to 65 mM.potassium
hydroxide following the elution of bromate (when injection valve #2 is
switched to the inject position)
1.0 mL/min
AS Autosampler Module (P/N 063105) Sample Prep options and a
large volume (8.2 mL) sample needle assembly (P/N 061267)
Dionex lonPac AG 19 Guard 4 x 50 mm (P/N 062887)
Dionex lonPac AS 19 Analytical 4 x 250 mm (P/N 062885)
-2300 psi
Dionex ASRS Ultra II, 4-mm (P/N 061561) with 4-mm Carbonate
Removal Device (CRD, P/N 062983)
DC-Module (P/N 061793) maintained @ 30° C
Conductivity Detector with integrated cell (P/N 061716) held @ 35° C
35 min
Standard Conditions and Equipment for Second Dimension Analyses a'b:
Ion Chromatograph:
Sample loop:
Load Volume:
Eluent Generator:
Eluent Flow:
Columns :
Typical System Back-pressure:
Conductivity Suppressor:
Chromatography Module
Detector:
Total analysis time:
Dionex ICS-3000 Dual System
Dionex UTAC-ULP1, 5 x 23-mm, concentrator column (P/N 063475)
Cut-window time set per procedures in Section 10.2.2 (approximately
2.0 mL)
Dionex ICS-3000 EG Eluent Generator Module (P/N 061714), with
dual channel EluGen Catridges (P/N 058900), isocratic 10 mM
potassium hydroxide step changed or ramped to 65 mM potassium
hydroxide following the elution of bromate for approximately 10
minutes and re-equilibrate at 10 mM hydroxide prior to injection
0.25 mL/min
Dionex lonPac AG 24 Guard 2 x 50 mm (P/N 064151)
Dionex lonPac AS 24 Analytical 2 x 250 mm (P/N 064153)
-2300 psi
Dionex ASRS Ultra II, 2-mm (P/N 061562) with 2-mm Carbonate
Removal Device (CRD, P/N 062986)
DC-Module (P/N 061793) maintained @ 30° C
Conductivity Detector with integrated cell (P/N 061716) held @ 35° C
35 min
(a) Mention of trade names or commercial products does not constitute endorsement or
recommendation for use. (b) It is the responsibility of the analyst to assure that the instruments,
supplies, and conditions used are capable of meeting all method QC requirements.
302.0-27
-------
TABLE 2. LOWEST CONCENTRATION MRL AND DL FOR BROMATE
WITH 2-D 1C
Injection
Volume
1.0 mL
Analyte
BrO3"
LCMRLa (^ig/L)
0.18
*DL (us/L)
0.12b
aLCMRL was calculated according to the procedure in reference 1.
*The DL was calculated from data acquired on a single day.
Replicate fortifications at 0.20 |ig/L.
TABLE 3. 1C PRECISION AND RECOVERY DATA FOR BROMATE IN VARIOUS
MATRICES WITH 2-D 1C (n=7) USING A 1.0-mL INJECTION VOLUME
Matrix
Reagent Water
*LFSSM
Ground water
Surface water 1
Spiked
Cone.
(UR/L)
0.50
5.0
0.50
5.0
0.50
5.0
0.50
5.0
Unspiked
Cone.
(UR/L)
<0.18
<0.18
<0.18
<0.18
0.63
0.63
0.46
0.46
Mean
% Rec.
101
99.1
104
96.2
96.1
100
89.8
103
% RSD
1.1
1.2
2.6
1.0
1.7
0.94
0.84
1.2
*Described in Section 3.11 and 7.2.2
302.0-28
-------
TABLE 4. INITIAL DEMONSTRATION OF CAPABILITY QUALITY CONTROL
REQUIREMENTS
Method
Reference
Requirement
Specification and
Frequency
Acceptance Criteria
Section
9.2.1
Demonstration of
Low System
Background
Analyze a LRB prior to
any other IDC steps.
Demonstrate that bromate is
below 1/3 of the MRL (Section
9.3.1) and that possible
interferences from sampling
protocols do not prevent the
identification and
quantification of bromate.
Section
9.2.2
Demonstration of
Precision
Analyze 7 replicate LFBs
and LFSSMs fortified near
the mid-point of the
calibration curve
%RSDmustbe < 20%.
Section
9.2.3
Demonstration of
Accuracy
Calculate average recovery
for replicates used in
Section 9.2.2.
Mean recovery within + 20%
of true value.
Section
9.2.5
Quality Control
Sample
During IDC, each time a
new analyte PDS is made,
every time the instrument
is calibrated and at least
quarterly.
The result for bromate must be
within 80-120% of the true
value.
302.0-29
-------
TABLE 5. ONGOING QUALITY CONTROL REQUIREMENTS (SUMMARY)
Method
Reference
Requirement
Specification and Frequency
Acceptance Criteria
Section 8.3
Sample Holding
Time
28 days when collected and stored
according to sections 8.1 and 8.2
with appropriate storage.
Sample results are valid only if
samples are analyzed within
sample hold time.
Section
9.3.1
Laboratory
Reagent Blank
(LRB)
Analyze a LRB as part of the IDC
(Section 9.2), as part of each
calibration, and with each
Analysis Batch
Demonstrate that bromate is
below 1/3 of the MRL and that
possible interferences from
sampling protocols do not
prevent the identification and
quantification of bromate.
Section
9.3.2
And 10.3
Continuing
Calibration Check
(CCC) Standards
Verify initial calibration by
analyzing a low-level CCC at the
beginning of each Analysis Batch.
Subsequent CCCs are required
after every 10 field samples, and
after the last field sample in a
batch.
Low CCC - at or below the MRL
concentration
Mid CCC - near midpoint in
calibration curve
High CCC - near the highest
calibration standard.
For each CCC the result must
be:
For CCCs < MRL:
% Rec within + 50% of the true
value
For CCCs > MRL: %Rec
within + 20% of the true value
Recalibration is recommended
if these criteria are not met.
Section
9.3.3
Laboratory
Fortified
Synthetic Sample
Matrix CCCs
(LFSSM CCC)
In order monitor the cut window
during an Analysis Batch, a high-
level CCC standard, prepared in
the LFSSM (Sect. 9.3.3) is also
required near the beginning of
each Analysis Batch.
For the LFSSM CCC the result
must be within + 20% of the
true value
Section
9.3.4
Laboratory
Fortified Blank
(LFB)
Analyze a LFB with each analysis
batch, rotating between low,
medium and high concentration
from batch to batch.
Low LFB - at or below the MRL
concentration
Mid LFB - near midpoint in
calibration curve
High LFB - near the highest
calibration standard.
For each LFB the result must
be:
For LFBs < MRL:
% Rec within + 50% of the true
value
For LFBs > MRL: %Rec
within + 20% of the true value
Recalibration is recommended
if these criteria are not met.
302.0-30
-------
TABLE 5. ONGOING QUALITY CONTROL REQUIREMENTS (Continued)
Method
Reference
Requirement
Specification and
Frequency
Acceptance Criteria
Section
9.3.5
Laboratory
Fortified Sample
Matrix (LFSM)
Analyze one LFSM per
Analysis Batch (20 field
samples or less). Fortify the
LFSM with bromate at a
concentration close to but
greater than the native
concentration (if known).
Calculate LFSM recoveries.
Recoveries for the LFSM must
be calculated (Sect. 9.3.5.2).
The result must be:
For LFSMs < MRL: % Rec
within + 50% of the true value
For LFSMs > MRL: %Rec
within + 20% of the true value
Section
9.3.6
Laboratory
Duplicate (LD) or
Laboratory
Fortified Sample
Matrix Duplicate
(LFSMD)
Analyze at least one LD or
LFSMD daily, or with each
Analysis Batch (20 samples
or less), whichever is more
frequent.
RPD must be calculated (Sect.
9.3.6.1 for LD and Sect. 9.3.6.3
for LFSMD). The result must
be:
For LFSMDs < MRL: % Rec
within + 50% of the true value
For LFSMDs > MRL: %Rec
within + 20% of the true value
Section
9.3.7
Quality Control
Sample (QCS)
During IDC, each time a new
analyte PDS is made, every
time the instrument is
calibrated and at least
quarterly.
Results must be within + 20%
of the expected value.
Section
10.2
Initial Calibration
Use external standard
calibration technique to
generate a first or second
order calibration curve. Use
at least 5 standard
concentrations.
Check the calibration curve
as described in Section 10.2.
Analyze a QCS near the mid-
point of the calibration
curve.
When each calibration standard
is calculated as an unknown
using the calibration curve, the
result should be:
For CALs < MRL: % Rec
within + 50% of the true value
For CALs > MRL: %Rec
within + 20% of the true value
Recalibration is recommended
if these criteria are not met.
302.0-31
-------
TABLE 6. SAMPLE ANALYSIS BATCH WITH QC REQUIREMENTS
Injection
#
1
2
O
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Sample
Description
Laboratory Reagent Blank (LRB)
CCCattheMRL
LFSSM CCC at high level
LFB
Sample 1
Sample 2
Sample 2 - Laboratory Fortified Sample Matrix (LFSM)
Sample 2 - Laboratory Fortified Sample Matrix Duplicate
(LFSMD)
Sample 3
Sample 4
Sample 5
Sample 6
Sample 7
Sample 8
Sample 9
Sample 10
CCC at mid level
Sample 1 1
Sample 12
Sample 13
Acceptance
Criteria
< 1/3 MRL
Recovery of 50- 150%
Recovery of 80 - 120%
< MRL 50-150% of value
> MRL 80-120% of value
normal analysis
normal analysis
Recovery of 80- 120%
%RPD = ±20%
normal analysis
normal analysis
normal analysis
normal analysis
normal analysis
normal analysis
normal analysis
normal analysis
Recovery of 80 - 120%
normal analysis
normal analysis
normal analysis
CONTINUED on NEXT PAGE
302.0-32
-------
TABLE 6. (Continued)
Injection
#
21
22
23
24
25
26
27
28
Sample
Description
Sample 14
Sample 15
Sample 16
Sample 17
Sample 18
Sample 19
Sample 20
CCC at high level*
Acceptance
Criteria
normal analysis
normal analysis
normal analysis
normal analysis
normal analysis
normal analysis
normal analysis
Recovery of 80 - 120%
* also requires first dimension chromatogram printout
302.0-33
-------
Figure 1. EPA Method 302.0 System Schematic
1st Dimension
2nd Dimension
waste "
Large Loop
Load
— Inject
Autosampler
Injection Valve 1
4mmAG/AS19
Column 1
External Water
Suppressor 1
CRD1
External Water- •
waste —
I
Injection Valve 2
CD 2
CRD2
^Suppressor 2
2mm AG/AS24 Column 2
Concentrator
Column
Transfer to 2-D
— Load Concentrator
I i 1
waste
302.0-34
-------
Figure 2. Setting the start and stop time for the cut window in the first dimension using a 1.0-mL
injection volume of a 15 ug/L BrOs" fortification in the LSSM and RW.
0.60
0.50
0.40-
0.30
MS
Set start of cut window at 8.0 min
0.20
0.10-
Return to baseline in RW@ 9.8 min
Start of bromate peak in LSSM @
8.5 min
-0.10
Set end of cut window at
10.0 min
0.0 1.0
3.0
5.0
7.0
9.0
11.0
13.0
302.0-35
-------
Figure 3. First and Second Dimension Chromatogram of 15.0 ug/L bromate fortification in the
LSSM.
0.40 -
-0.10-
-0 15 n ' ' ' i ' ' ' i ' ' ' i ' ' ' i ' ' ' i
0.0 4.0 8.0
mm
12.0
16.0
20.0
24.0
28.0
32.0
37.0
302.0-36
-------
Figure 4. Typical 1st and 2nd Dimension Chromatogram of a municipal groundwater disinfected
with chlorine and fortified with 0.50 ug/L bromate. The native level of bromate was 0.41 ug/L and
recovery was 104 percent.
0.250
0.200
0.150-
0.100
0.050-
0.000
0.050
-0.100] . .
0.0
MS
4.0
8.0
12.0
16.0
20.0
24.0
28.0
32.0
mm
37.0
302.0-37
------- |