EPA Document # EPA 815-B-09-009
METHOD 524.3 MEASUREMENT OF PURGEABLE ORGANIC COMPOUNDS IN
WATER BY CAPILLARY COLUMN GAS CHROMATOGRAPHY/MASS
SPECTROMETRY
Version 1.0
June 2009
B. Prakash, A. D. Zaffiro, and M. Zimmerman (Shaw Environmental, Inc.)
D. J. Munch (U.S. EPA, Office of Ground Water and Drinking Water)
B. V. Pepich (U.S. EPA, Region 10 Laboratory)
TECHNICAL SUPPORT CENTER
OFFICE OF GROUND WATER AND DRINKING WATER
U. S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
524.3-1
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METHOD 524.3
MEASUREMENT OF PURGEABLE ORGANIC COMPOUNDS IN WATER BY CAPILLARY
COLUMN GAS CHROMATOGRAPHY/MASS SPECTROMETRY
1. SCOPE AND APPLICATION
1.1 This is a gas chromatography/mass spectrometry (GC/MS) method for the determination of
purgeable organic compounds in finished drinking waters. Discontinuous scanning modes
such as selected ion monitoring (SIM) and selected ion storage (SIS) are permitted for
determining selected analytes that are monitored at levels too low for the full scan detection
mode. Precision and accuracy data have been generated for the method analytes in reagent
water, drinking water from a groundwater source, and drinking water from a surface water
source. The single laboratory Lowest Concentration Minimum Reporting Level (LCMRL)
has also been determined in reagent water. The following compounds can be determined
using this method:
Analyte
1,1,1,2-tetrachloroethane
1,1,1 -trichloroethane
1,1,2,2-tetrachloroethane
1,1,2-trichloroethane
1,1-dichloroethane
1,1-dichloroethene
1,1 -dichloropropene
1,2,3-trichlorobenzene
1,2,3-trichloropropane
1,2,4-trichlorobenzene
1,2,4-trimethylbenzene
l,2-dibromo-3-chloropropane
1,2-dibromoethane
1,2-dichlorobenzene
1,2-dichloroethane
1,2-dichloropropane
1,3,5-trimethylbenzene
1,3-butadiene a
1,3-dichlorobenzene
1,3 -di chl oropropane
1,4-dichlorobenzene
1-chlorobutane
2-chlorotoluene
4-chlorotoluene
4-i sopropyltoluene
Chemical Abstract Services Registry
Number (CASRN)
630-20-6
71-55-6
79-34-5
79-00-5
75-34-3
75-35-4
563-58-6
87-61-6
96-18-4
120-82-1
95-63-6
96-12-8
106-93-4
95-50-1
107-06-2
78-87-5
108-67-8
106-99-0
541-73-1
142-28-9
106-46-7
109-69-3
95-49-8
106-43-4
99-87-6
524.3-2
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Analyte
allyl chloride
benzene
bromobenzene
bromochloromethane
bromodichloromethane
bromoform
bromomethane
carbon disulfide
carbon tetrachloride
chlorobenzene
chlorodifluoromethane a
chloroform
chloromethane
cis-l,2-dichloroethene
cis-l,3-dichloropropene
dibromochloromethane
dibromomethane
di chlorodifluoromethane
di ethyl ether
diisopropyl ether (DIPE) b
ethyl methacrylate
ethylbenzene
hexachl orobutadi ene
hexachloroethane
isopropylbenzene
methyl acetate c
methyl iodide
methyl ene chloride
methyl-t-butyl ether (MtBE)
m-xylene
naphthalene
n-butylbenzene
n-propylbenzene
o-xylene
pentachloroethane
p-xylene
sec-butylb enzene
styrene
t-amyl ethyl ether (TAEE) b
t-amyl methyl ether (TAME) b
t-butyl alcohol (TEA)b
Chemical Abstract Services Registry
Number (CASRN)
107-05-1
71-43-2
108-86-1
74-97-5
75-27-4
75-25-2
74-83-9
75-15-0
56-23-5
108-90-7
75-45-6
67-66-3
74-87-3
156-59-2
10061-01-5
124-48-1
74-95-3
75-71-8
60-29-7
108-20-3
97-63-2
100-41-4
87-68-3
67-72-1
98-82-8
79-20-9
74-88-4
75-09-2
1634-04-4
108-38-3
91-20-3
104-51-8
103-65-1
95-47-6
76-01-7
106-42-3
135-98-8
100-42-5
919-94-8
994-05-8
75-65-0
524.3-3
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Chemical Abstract Services Registry
Analvte Number (CASRN)
t-butyl ethyl ether (ETBE) b 637-92-3
t-butylbenzene 98-06-6
tetrachloroethene 127-18-4
tetrahydrofuran 109-99-9
toluene 108-88-3
trans- 1,2-dichloroethene 156-60-5
trans-1,3 -dichloropropene 10061 -02-6
trichloroethene 79-01-6
trichlorofluoromethane 75-69-4
vinyl chloride 75-01-4
New in revision 524.3: emerging contaminant of interest
New in revision 524.3: reformulated gasoline additive
New in revision 524.3: potential breakdown product of MtBE
1.2 The mass spectrometry conditions described in this method were developed using a gas
chromatograph (GC) interfaced to a quadrupole mass spectrometer (MS).
1.3 The single laboratory LCMRL is the lowest spiking concentration such that the probability of
spike recovery in the 50% to 150% range is at least 99%. Single laboratory LCMRLs for the
analytes in this method ranged from 0.030 to 0.35 microgram per liter (|ig/L) in the full scan
mode, and are listed in Table 6. Single laboratory LCMRLs were also determined for selected
analytes in the selected ion monitoring (SIM) mode (Table 10). The procedure used to
determine the LCMRL is described elsewhere.1
1.4 Laboratories using this method are not required to determine LCMRLs, but they must
demonstrate that the minimum reporting level (MRL) for each analyte meets the requirements
described in Section 9.2.4.
1.5 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.2 The DL is
dependent on sample matrix, fortification concentration, and instrument performance. Deter-
mining the DL for analytes in this method is optional (Sect. 9.2.6). DLs for method analytes
fortified into reagent water ranged from 0.0077 to 0.14 |ig/L in the full scan mode. These
values are presented in Table 6. DLs were also determined for selected analytes in SIM mode
(Table 10).
1.6 This method is intended for use by analysts skilled in the technique of purge-and-trap
concentration, the operation of GC/MS instrumentation, and the interpretation of the
associated data.
1.7 METHOD FLEXIBILITY - In recognition of technological advances in analytical
instrumentation and techniques, the laboratory is permitted to modify purge-and-trap
parameters and the GC/MS conditions. Because the purge-and-trap technique has a
significant number of analyst-chosen parameters, and because it employs a procedural
524.3-4
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calibration, the authors have determined an acceptable range of purge-and-trap conditions that
may be used (Sect. 9.1) and a means by which to evaluate method modifications (Sect. 9.4).
Changes may not be made to sample collection and preservation (Sect. 8) or to the
quality control (QC) requirements (Sect. 9). Modifications that are introduced solely in the
interest of reducing cost or sample processing time, but result in poorer method performance,
may not be used. The option to operate the MS in SIM or SIS mode is restricted to analytes
that cannot be effectively analyzed in full scan mode for compounds of interest, e.g., 1,2-
dibromoethane and l,2-dibromo-3-chloropropane. The SIM detection mode should not be
used to enhance analyte signal for instrumentation that is not properly optimized and
maintained. Trihalomethanes (THMs) and other commonly occurring contaminants in
drinking water must be analyzed in the full scan detection mode. In all cases where method
modifications are proposed, the analyst must perform the procedures outlined in the Initial
Demonstration of Capability (IDC, Sect. 9.2), verify that all QC acceptance criteria in this
method (Tables 15 and 16) are met, and verify method performance in real sample matrices
(Sect. 9.4.4).
NOTE: This description of method flexibility is an abbreviated summation. Additional
specific detail is provided throughout the method, which supersedes the above general
guidance.
2. SUMMARY OF METHOD
Headspace-free samples are collected in amber, glass vials with polytetrafluoroethylene (PTFE)-
faced septa. Samples are dechlorinated with ascorbic acid and the pH is adjusted with maleic acid.
A 5.0-milliliter (mL) aliquot of the sample is transferred to a glass sparging vessel along with
appropriate amounts of internal standard and quality control compounds. The method analytes are
purged from the water using helium and trapped on a sorbent material. After purging, the trap may
be dry purged for a short period to remove water. Additional water management techniques may be
applied. The trap is heated and backflushed with helium to transfer the analytes directly into a gas
chromatographic inlet. The inlet is operated in the split mode in order to achieve the desired desorb
flow rates and further reduce water transmission. Analytes are transferred onto a capillary GC
column, which is temperature programmed to optimize the separation of method analytes.
Compounds eluting from the GC are directed into a mass spectrometer for detection and
quantitation. The method analytes are identified by comparing the acquired mass spectra and
retention times to reference spectra and retention times for calibration standards acquired under
identical GC/MS conditions. The concentration of each analyte is calculated using the internal
standard technique and response curves obtained via procedural calibration (Sect. 3.18).
3. DEFINITIONS
3.1 ANALYSIS BATCH - A sequence of samples, analyzed within a 24-hour period, including
no more than 20 field samples. Each Analysis Batch must also include all required QC
samples, which do not contribute to the maximum field sample total of 20. The required QC
samples include:
Laboratory Reagent Blank (LRB),
Continuing Calibration Check (CCC) Standards,
Laboratory Fortified Sample Matrix (LFSM), and
Laboratory Fortified Sample Matrix Duplicate or Field Duplicate (LFSMD or FD).
524.3-5
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3.2 CALIBRATION STANDARD - An aqueous solution of the method analytes prepared from
the Primary Dilution Standard solution. The calibration standard solutions are used to
calibrate the instrument response with respect to analyte concentration.
3.3 CONTINUING CALIBRATION CHECK (CCC) - A calibration standard containing the
method analytes, internal standards and surrogate analytes, which is analyzed periodically to
verify the accuracy of the existing calibration.
3.4 DESORB FLOW RATE - The rate at which gas is passed through the sorbent trap during the
desorb cycle. The desorb flow rate is approximately equal to the total flow rate through the
GC inlet (mL/min).
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.
3.6 DRY PURGE VOLUME - The total volume of purge gas (mL) bypassing the sparging vessel
and passing through the sorbent trap during the dry purge cycle as a moisture control measure.
3.7 FIELD DUPLICATE (FD) - Separate samples collected at the same time, shipped and stored
under identical conditions. Method precision, including the contribution from sample
collection procedures, is estimated from the analysis of FDs. For the purposes of this method,
Field Duplicates are necessary to conduct repeat analyses if the original field sample is lost, or
to conduct repeat analyses in the case of QC failures associated with the analysis of the
original field sample. Field Duplicates are used to prepare Laboratory Fortified Sample
Matrix (Sect. 3.11) and Laboratory Fortified Sample Matrix Duplicate (Sect. 3.12) QC
samples.
3.8 FIELD REAGENT BLANK (FRB) - An aliquot of reagent water that is placed in a sample
container in the laboratory and treated as a sample in all respects, including shipment to the
sampling site, exposure to sampling site conditions, storage, preservation, and all analytical
procedures. The purpose of the FRB is to determine if method analytes or other interferences
are introduced into the samples during transport and storage.
3.9 INTERNAL STANDARD (IS) - A pure compound added to all standard solutions, field
samples and QC samples in a known amount. Each internal standard is assigned to a specific
analyte or multiple analytes, and is used to measure relative response.
3.10 LABORATORY FORTIFIED BLANK (LFB) - An aliquot of reagent water to which known
quantities of the method analytes are added. The LFB is analyzed in the same manner as a
sample, including the preservation procedures in Section 8. The LFB is used during the IDC
to verify method performance for precision and accuracy.
3.11 LABORATORY FORTIFIED SAMPLE MATRIX (LFSM) - A Field Duplicate to which
known quantities of the method analytes are added. The LFSM is processed and analyzed as a
sample, and its purpose is to determine whether the sample matrix contributes bias to the
524.3-6
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analytical results. For this method, separate field samples are required for preparing fortified
matrix so that sampling error is included in the accuracy estimate.
3.12 LABORATORY FORTIFIED SAMPLE MATRIX DUPLICATE (LFSMD) - A second Field
Duplicate, of the same sample used to prepare the LFSM, which is fortified identically to the
LFSM. The LFSMD is used instead of the Field Duplicate to assess method precision and
accuracy when the occurrence of the method analytes is infrequent. For this method, separate
field samples are required for preparing fortified matrix so that sampling error is included in
the precision estimate.
3.13 LABORATORY REAGENT BLANK (LRB) - An aliquot of reagent water containing the
preservatives, internal standards and surrogate analytes. The LRB is used to determine if the
method analytes or interferences are introduced from the laboratory environment, the reagents
or glassware. The LRB is also used to test for cross contamination in the purge-and-trap
system.
3.14 LOWEST CONCENTRATION MINIMUM REPORTING LEVEL (LCMRL) - The single
laboratory LCMRL is the lowest spiking concentration such that the probability of spike
recovery in the 50% to 150% range is at least 99%.l
3.15 MATERIAL SAFETY DATA SHEETS (MSDS) - Written information provided by vendors
concerning a chemical's toxicity, health hazards, physical properties, fire and reactivity data,
storage instructions, spill response procedures, 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 method analyte in a sample following analysis.
This 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 each method analyte.
3.17 PRIMARY DILUTION STANDARD (PDS) - A solution containing the method analytes (or
internal standards and surrogate analytes) prepared in the laboratory from Stock Standard
Solutions and diluted as needed to prepare calibration standards and sample fortification
solutions.
3.18 PROCEDURAL CALIBRATION - A calibration technique in which calibration standards are
processed through the entire method, including sample preparation, addition of preservatives,
extraction and concentration.
3.19 PURGE FLOW RATE - The rate (mL/min) that the purge gas flows through the sparging
vessel during the purge cycle.
3.20 PURGE VOLUME - The total volume of purge gas (mL) that flows through the sparging
vessel during the purge cycle.
3.21 QUALITY CONTROL SAMPLE (QCS) - A solution containing the method analytes at a
known concentration that is obtained from a source external to the laboratory and different
from the source of calibration standards. The purpose of the QCS is to verify the accuracy of
the primary calibration standards.
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3.22 REAGENT WATER - Purified water that does not contain any measurable quantity of the
method analytes or interfering compounds at or above /^ the MRL.
3.23 STOCK STANDARD SOLUTION (SSS) - A concentrated solution containing one or more
of the method analytes that is 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.
3.24 SURROGATE ANALYTE - A pure analyte which is extremely unlikely to be found in any
sample, and which is added to a sample aliquot in a known amount before analysis.
Surrogates are measured with the same procedures used to measure other sample components.
Because surrogates are present in every sample, they provide a means of assessing method
performance for a specific purge-and-trap analysis cycle.
4. INTERFERENCES
4.1 SAMPLE CONTAINERS, SHIPPING AND STORAGE - Volatile organic compounds
(VOCs) present in ambient air, shipping containers, and in the laboratory environment may
permeate the PTFE-lined septa of the sample vials or be present at high concentrations in the
headspace of the vial—especially if the vials were prepared in a laboratory. Contamination
from these sources is assessed by analyzing Field Reagent Blanks as described in Section
9.3.9.
4.2 PURGE AND TRAP SYSTEM - Commercially available purge-and-trap concentrators and
autosamplers have complex sample paths that are subject to cross contamination, which is
commonly referred to as "carryover." Carryover is controlled by minimizing the transfer line
length from the autosampler to the sparging vessel and optimizing the bake cycle and rinse
cycle parameters. The potential for carryover in the purge-and-trap system is evaluated during
the Initial Demonstration of Capability by analyzing the highest concentration calibration
standard followed by an LRB.
4.3 REAGENTS - All laboratory reagents must be routinely demonstrated to be free from
interferences under the conditions of the analysis. This may be accomplished by analyzing
LRBs and meeting the acceptance criterion as described in Section 9.3.1.
4.3.1 REAGENT WATER - Analysts may observe common laboratory contaminants, such
as methylene chloride, in reagent water. Boiling and/or sparging reagent water with
nitrogen is recommended. If possible, prepare aqueous standards and blanks in a
laboratory environment isolated from ambient sources of VOCs.
4.3.2 METHANOL - Traces of ketones, methylene chloride, and other organic solvents
could be present in methanol. Purge-and-trap-grade methanol is prescribed for use
with this method.
4.3.3 PRESERVATION REAGENTS - The potential exists for trace-level organic
contaminants in the preservation reagents. Interferences from these sources must be
monitored by analysis of LRBs when new lots of reagents are acquired.
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4.3.4 SORBENT MATERIALS - Sorbent traps must be carefully evaluated because some
traps, when heated, have been reported to produce small amounts of VOCs,
particularly with extended use. For example, toluene may be detected the first time a
trap is desorbed during a work shift. For this reason, a short bake cycle prior to
beginning an analysis sequence is recommended.
4.3.5 PURGE GAS SUPPLY - Helium used to purge samples is a potential source of
common laboratory contaminants. Trace VOCs in the purge gas, supply lines, or
permeating from the gas supply system—including the regulator—will concentrate on
the sorbent trap. High-purity gas supplies and high-purity gas regulators are
recommended to minimize contamination from these sources. Purge gas filters
should be regenerated or replaced at the intervals specified by the manufacturers.
4.4 MATRIX INTERFERENCES - Matrix interferences are 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. The analysis of Laboratory Fortified
Sample Matrix (Sect. 9.3.7) provides evidence for the presence (or absence) of matrix effects.
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.3 The OSHA
laboratory standards can be found on line at
http://www.osha.gov/SLTC/laboratories/standards.html. A reference file of MSDSs should be
made available to all personnel involved in the chemical analysis.
5.2 Pure standard materials and Stock Standard Solutions of the method compounds should be
handled with suitable protection for skin, eyes, etc.4
6. EQUIPMENT AND SUPPLIES
References to specific brands or catalog numbers are included as examples only and do not imply
endorsement of the product. These references do not preclude the use of other vendors or supplies.
6.1 SAMPLE CONTAINERS - Clean, amber volatile organic analysis (VGA) vials fitted with
PTFE-faced silicone septa and polypropylene screw caps (I-Chem Cat. No. S146-0040 or
equivalent). Prior to reuse, wash vials and septa (if not punctured) with detergent and rinse
with tap and distilled water. Place vials in a 105 degrees Centigrade (°C) oven for one hour,
then allow to cool in an area isolated from ambient sources of VOCs.
6.2 MICRO SYRINGES - Suggested sizes include 2.0, 5.0, 10, and 25 |iL.
6.3 PURGE-AND-TRAP SYRINGES - 5-mL glass syringes with PTFE Luer-Lok (Hamilton
Model No. 1005 TLL or equivalent) for manual loading of samples into a sparging vessel.
6.4 SYRINGE VALVE - two-position syringe valves with Luer ends (Supelco Cat. No. 20926 or
equivalent) for use sealing purge-and-trap syringes (Sect. 6.3).
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6.5 VOLUMETRIC FLASKS - Class A, suggested sizes include 50, 100, and 200 mL for
preparation of calibration standards.
6.6 ANALYTICAL BALANCE - Capable of weighing to the nearest 0.0001 gram (g).
6.7 MICRO-REACTION VESSEL - 0.3-, 1.0-, 2.0-, 5.0-mL sizes (Supelco CatNos. 33291,
33293, 33295, 33299, or equivalent) equipped with Mininert Valves [Supelco Cat No. 33301
(15 millimeter (mm) for 0.3-, 1.0-, and 2.0-mL vials) and Cat No. 33303 (20 mm for 5.0-mL
vials)]. These vials are recommended for storage of Stock Standard Solutions and Primary
Dilution Standards prepared in methanol.
6.8 PURGE AND TRAP SYSTEM - Any purge-and-trap unit that is capable of being
electronically interfaced to the GC to trigger the GC run and that is capable of meeting the
method QC requirements outlined in Section 9 is permitted. The concentrator(s) may be
equipped with an autosampler. Moisture control modules are permitted but not required.
6.8.1 SPARGING VESSEL - Instruments must be equipped with a sparging vessel
specifically designed for purging a 5-mL sample volume. A glass frit should be
installed at the base of the sample chamber so the purge gas passes through the water
column as finely divided bubbles with a diameter of less than 3 mm at the origin.
NOTE: Larger sparging vessels are not allowed. While the larger sample volume
could result in the transfer of more analyte to the trap, purging efficiency decreases
unless the purge volume is increased proportionally. While the procedural calibration
technique corrects for this, lower purging efficiency decreases method precision. In
addition, larger purge volumes could result in the transfer of more water vapor to the
trap, placing increased demand on the efficiency of moisture control devices.
6.8.2 SORBENT TRAP - Purge-and-trap manufacturers typically recommend specific
sorbent traps for use with their instruments. Any trap design is acceptable provided
the data acquired meet all QC criteria described in Section 9.
NOTE: During method development studies, a trap containing Tenax, silica gel and
coconut charcoal in series exhibited complete breakthrough of
chlorodifluoromethane. A trap containing Tenax, silica gel and carbon molecular
sieve (CMS) exhibited partial breakthrough for chlorodifluoromethane.
Chlorodifluoromethane cannot be analyzed using this method if these traps and traps
of similar design, containing Tenax, silica gel and coconut charcoal, or Tenax, silica
gel and CMS, are used.
6.8.3 TRANSFER LINE - Silcosteel®, or equivalent, heated transfer line used to transfer
the desorbed analytes from the purge-and-trap concentrator to the injection port of the
GC.
6.8.4 SAMPLE HEATER - A sparging vessel heater is optional. Resistance or infrared
heaters may be used.
524.3-10
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6.8.5 REFRIGERATED AUTOSAMPLER - Vial autosamplers must be capable of
maintaining samples at a temperature of 10 °C or lower. Verify the temperature of
field samples placed in the autosampler using an external thermocouple or
thermometer (inserted into a vial containing water) during the IDC and reconfirm at
least quarterly. This temperature must not be altered after collecting the initial
calibration because it may change analyte purging efficiencies.
6.8.6 STANDARD ADDITION MODULE - Automated device incorporated into vial
autosamplers capable of fortifying internal standards and surrogate analytes directly
into the sparging vessel. A standard addition module is recommended when vial
autosamplers are used to conduct this method.
6.8.7 TANDEM PURGE-AND-TRAP OPERATION - A technique allowing use of two
purge-and-trap concentrators configured in tandem. The IDC procedure (Sect. 9.2)
must be conducted for each concentrator. In addition, this option requires separate
QC samples for each sample path (Sect. 9.3), separate calibrations (Sect. 10), and the
use of a marker compound (Sect. 10) to uniquely identify the sample path.
6.9 GAS CHROMATOGRAPHY MASS SPECTROMETRY SYSTEM/DATA SYSTEM
(GC/MS/DS)
6.9.1 GC INJECTOR AND OVEN - The GC must be capable of temperature programming
and must be equipped with a standard split/splitless injector and a flow controller that
is compatible with purge-and-trap analysis. In this configuration, the purge-and-trap
effluent is plumbed directly to the carrier gas inlet line of a split/splitless injection
port. The injection port is operated in split mode to achieve the desired desorb flow
rate and reduce water transmission. A deactivated glass liner (Restek Cat. No. 20972
or equivalent) is recommended to minimize dead volume and active sites within the
GC inlet.
6.9.2 FUSED SILICA CAPILLARY GC COLUMN - Laboratories must use a column
specifically designed for analysis of volatile organic compounds by purge and trap.
The column must have an i.d. of 0.32 mm or less to be compatible with operation in
the split mode (Sect. 6.9.1). The column must be capable of resolving the method
analytes such that a unique quantitation ion is available for each analyte that is free
from interference due to an identical fragment ion in any co-eluting (or overlapping)
peak(s).
6.9.3 GC/MS INTERFACE - The mass spectrometer must have sufficient vacuum
pumping capacity to allow the direct feed of the analytical column to the ion source.
6.9.4 MASS SPECTROMETER (MS) - The MS must be capable of electron ionization
(El) at a nominal energy of 70 electron volts (eV) and must be operated in the
positive ion mode. An ion-trap mass spectrometer, tuned to produce mass spectra
that approximate standard, library spectra obtained under El conditions, may be used.
The instrument must be capable of obtaining at least six scans during elution of each
chromatographic peak. Seven to ten scans across chromatographic peaks are
recommended. The spectrometer must produce a mass spectrum that meets all
524.3-11
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criteria in Table 1 when 4-bromofluorobenzene (BFB) is introduced into the GC/MS
(Sect. 10.1.1).
6.9.5 DATA SYSTEM - An interfaced data system is required to acquire, store, reduce,
and output mass spectral data. The computer software must have the capability of
processing stored GC/MS data by recognizing a GC peak within any given retention
time window, comparing the mass spectra from the GC peak with spectral data in a
user-created data base, and generating a list of tentatively identified compounds with
their retention times and scan numbers. The software must allow integration of the
ion abundance of any specific ion between specified time or scan number limits. The
software must also allow construction of linear or second-order regression calibration
curves, and calculation of concentrations using the internal standard technique.
7. REAGENTS AND STANDARDS
7.1 REAGENTS AND SOLVENTS - Reagent grade or better chemicals must be used. 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 as long as the reagent is of sufficiently
high purity to permit its use without negatively affecting data quality.
7.1.1 HELIUM - Ultra High Purity (99.999%) or equivalent, for use as GC carrier gas and
purge gas.
7.1.2 REAGENT WATER - Purified water which does not contain any measurable
quantities of any method analytes or interfering compounds at or above /^ the MRL
for each compound of interest.
7.1.3 METHANOL (CH3OH, CAS# 67-56-1) - Purge-and-trap grade, demonstrated to be
free of analytes and interferences (Burdick & Jackson Brand® for Purge and Trap
Analysis Cat. No. 232 or equivalent).
7.1.4 ASCORBIC ACID (C6H8O6,CAS# 50-81-7)-Dechlorinating agent, demonstrated to
be free of analytes and interferences (Alfa Aesar Cat. No. A15613 or equivalent).
7.1.5 MALEIC ACID (C4H4O4, CAS# 110-16-7) - Used as a preservative and to lower pH
for the purpose of preventing dehydrohalogenation of chlorinated analytes. High
purity, demonstrated to be free of analytes and interferences (Sigma Cat. No. M0375
or equivalent).
7.1.6 SODIUM THIOSULFATE (Na2S2O3, CAS# 7772-98-7) - Optional dechlorinating
agent when sampling only for THMs (Sigma Cat. No. 563188 or equivalent).
7.2 STOCK STANDARD SOLUTIONS - Certified mixes of the 524.3 method analytes, the
internal standards and the surrogate analytes are recommended. Users may prepare stock
standards of the liquid and solid analytes, if not available as certified solutions, following the
guidance provided in this section. After opening the sealed ampoules, store commercial
mixes in micro-reaction vials with Mininert caps (Sect. 6.7) at a temperature of-10 °C or
lower. After transfer, replace vendor-supplied, stock solutions within one month.
524.3-12
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NOTE: Methyl iodide may degrade faster than other liquid analytes. Monitor the area of this
compound relative to the internal standard, 1, 4-difluorobenzene. Replace the stock standard
if methyl iodide shows evidence of degradation.
7.2.1 INTERNAL STANDARD STOCK SOLUTIONS (ISSS) (1000 to 2500 |ig/mL) -
This method uses three internal standards: 1,4-difluorobenzene (CAS# 540-36-3),
chlorobenzene-Js (CAS# 3114-55-4) and l,4-dichlorobenzene-J4 (CAS# 3855-82-1).
7.2.2 SURROGATE STOCK STANDARDS (SURSS) (1000 to 2500 |ig/mL) - This
method uses three surrogate analytes: methyl-t-butyl-ether-J3 (CAS# 29366-08), BFB
(CAS# 460-00-4) and l,2-dichlorobenzene-J4 (CAS# 2199-69-1).
NOTE: During method development, methyl-t-butyl-ether-t/3 was obtained as the neat
compound (Aldrich Cat. No. 43413-2 or equivalent).
7.2.3 ANALYTE STOCK STANDARD SOLUTIONS - Obtain the analytes listed in the
table in Section 1.1 as certified mixes in methanol, or as neat standards if necessary.
During method development, the reformulated gasoline additives were obtained as
custom mixes in methanol and as neat materials. Chlorodifluoromethane, and 1,3-
butadiene (new method analytes in revision 524.3) were obtained as custom mixes in
methanol.
7.2.4 PREPARATION INSTRUCTIONS FOR LIQUID ANALYTES - Prepare the stock
standards individually at 10 mg/mL. Using an analytical balance, obtain a tare weight
for a VOA vial containing 20-mL of purge-and-trap-grade methanol. To achieve the
10 mg/L nominal concentration, calculate the volume of the liquid analyte
corresponding to 200 mg. Carefully measure this volume with a 250-jiL syringe and
inject the entire quantity under the surface of the methanol. Subtract the tare weight
from the final weight to calculate the exact solution concentration. When a
compound's purity is assayed to be 96 percent or greater, the weight can be used
without correction to calculate the concentration of the stock standard.
7.2.5 PREPARATION INSTRUCTIONS FOR SOLID ANALYTES - Prepare the stock
standards individually at 10 mg/mL by weighing 200 mg of each solid analyte into a
40-mL VOA vial and diluting to 20 mL. Using an analytical balance, weigh
approximately 200 mg of the solid material using a small glass weigh boat or similar
device. Transfer the solid to a 40-mL VOA vial and add 20-mL of purge-and-trap-
grade methanol. For semi-solid and other difficult to transfer materials, insert the
entire weigh boat into a VOA vial containing 20-mL of methanol. If the measured
mass of analyte is not exactly 200 mg, adjust the volume of methanol to achieve a
nominal concentration of 10 mg/mL. When a compound's purity is assayed to be 96
percent or greater, the weight can be used without correction to calculate the
concentration of the stock standard.
524.3-13
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7.2.6 STORAGE OF INDIVIDUAL STOCK STANDARDS - Store stock standards in the
VOA vials in which they were prepared. Stock standard solutions of liquid and solid
analytes prepared in-house are estimated to be stable for at least six months if stored at
-10 °C or colder. However, such solutions may be stable for longer periods depending
on the analyte. Laboratories must use accepted QC practices to determine when stock
standards need to be replaced.
7.3 PRIMARY DILUTION STANDARDS - Prepare Primary Dilution Standards by combining
and diluting appropriate volumes of the stock standards with purge-and-trap-grade methanol.
7.3.1 INTERNAL STANDARD AND SURROGATE PRIMARY DILUTION
STANDARD (IS/surrogate PDS) - Prepare a combined internal standard and
surrogate PDS from the ISSS and SURSS. Field samples and calibration standards
must contain the same concentration of internal standards and surrogates, and the
quantity of methanol added should be minimized. Between one and 5 jiL per 5-mL
sample is recommended. An IS/surrogate PDS concentration that results in the
aqueous concentration falling in the mid-range of the initial calibration, e.g., 5 |ig/L in
full scan mode and 0.5 |ig/L in SIM mode is recommended. Store the IS/surrogate
PDS in a glass vial with Teflon-lined septa at a temperature of-10 °C or colder.
However, the IS/surrogate PDS may be held at room temperature for extended periods
(several months) if stored in the sealed reservoir of a standard addition module.
7.3.2 ANALYTE PRIMARY DILUTION STANDARD (analyte PDS) - The analyte PDS is
used to prepare the calibration standards and to fortify LFBs, LFSMs and LFSMDs
with the method analytes. The analyte PDS is prepared by combining appropriate
volumes of the analyte stock standard solutions to achieve concentrations appropriate
for preparing aqueous calibration standards and fortifying samples. Choose
concentrations such that at least 2 jiL of the PDS is transferred to achieve the desired
aqueous concentration in the standard or QC samples. During method development,
PDS solutions ranged in concentration from 10 |ig/mL to 400 jig/mL. Lower
concentrations of the analyte PDS may be necessary when conducting analyses in SIM
mode. Store analyte PDS solutions in micro-reaction vials with Mininert caps at a
temperature of -10 °C or colder. PDS solutions which contain gasses must be replaced
after one week; those which do not contain gases may be stored for up to one month.
7.4 CALIBRATION STANDARDS - Prepare procedural calibration standards by diluting the
analyte PDS into reagent water containing the method preservatives (Sect. 8.1) at the same
concentrations used to collect the samples. A constant concentration of each internal standard
and surrogate analyte is added to each calibration standard, either manually or by use of an
automated standard addition module (Sect. 6.8.6). The lowest concentration calibration
standard must be at or below the MRL. These calibration standards may also be used as
CCCs. The dilution schemes for calibration standards that were used to collect method
performance data in Section 17 are provided in the tables below.
524.3-14
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Typical concentrations for aqueous calibration standards in scan mode used during method
development:
CALa Level
1
2
o
J
4
5
6
7
Analyte PDS Cone. (jig/mL)
10
10
100
100
400
400
400
Analyte PDS
Volume (uL)
5.0
10
2.0
5.0
2.5
5.0
10
Final CAL Std. Volume (L)
0.100
0.100
0.100
0.100
0.100
0.100
0.100
Final CAL Std. Cone.
(Hg/L)
0.50
1.0
2.0
5.0
10
20
40
CAL = calibration standard.
Typical concentrations for aqueous calibration standards in SIM mode used during method
development:
CAL Level
1
2
3
4
5
6
7
8
9
10
11
Analyte PDS Cone. (jig/mL)
0.1
0.1
0.1
1.0
1.0
1.0
10
10
10
100
100
Analyte PDS
Volume QiL)
2.0
5.0
10
2.5
5.0
10
2.0
5.0
10
2.0
5.0
Final CAL Std. Volume (L)
0.100
0.100
0.100
0.100
0.100
0.100
0.100
0.100
0.100
0.100
0.100
Final CAL Std. Cone.
(ng/L)
2.0
5.0
10
25
50
100
200
500
1,000
2,000
5,000
7.5 GC/MS TUNE CHECK SOLUTION, BFB (CAS# 460-00-4) - Use the IS/surrogate analyte
PDS (Sect. 7.3.1).
8. SAMPLE COLLECTION, PRESERVATION, AND STORAGE
8.1 SAMPLE COLLECTION
8.1.1 Prior to shipment to the field, maleic and ascorbic acid must be added to each sample
bottle. Cap the vials tightly to avoid spillage of the preservation reagents. If using a
40-mL vial, add 25 mg of ascorbic acid and 200 mg of maleic acid. If other
collection volumes are used, adjust the amount of the preservation reagents so that the
final concentrations of ascorbic and maleic acid in the sample containers are 0.625
g/L and 5 g/L, respectively. Using narrow-range pH paper, periodically verify that
sample pH is ~2 for each sample source.
8.1.2 If a sample foams vigorously when added to a VOA vial containing maleic and
ascorbic acids, discard the sample. Collect another sample for that location, but do
not add the method preservatives. Document these samples as "not acidified."
Unpreserved samples must be analyzed within 24 hours of collection.
524.3-15
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8.1.3 If sampling only for the THMs, you may preserve samples with sodium thiosulfate.
Add 3 mg to each 40-mL VOA vial prior to sample collection. Do not add ascorbic
or maleic acid when employing this preservation option.
NOTE: If the residual chlorine is likely to be present at greater than 5 mg/L, a
determination of the chlorine concentration may be necessary. Add an additional 25
mg of ascorbic acid or 3 mg of sodium thiosulfate per each 5 mg/L of residual
chlorine for each 40-mL of sample.
8.1.4 Grab samples must be collected in accordance with standard sampling practices.5
When sampling from a cold water tap, remove the aerator, open the tap and allow the
system to flush until the water temperature has stabilized (approximately 3 to 5
minutes). Fill sample bottles to overflowing, but take care not to flush out the rapidly
dissolving solid preservatives. No air bubbles should pass through the sample as the
bottle is filled, or be trapped in the sample when the bottle is sealed.
8.1.5 When sampling from an open body of water, fill a beaker with water collected from a
representative area. Use this bulk sample to generate individual samples and Field
Duplicates as needed.
8.2 FIELD REAGENT BLANKS
8.2.1 Duplicate FRBs must accompany each sample set, which is composed of the samples
collected from the same general sampling site at approximately the same time. At the
laboratory, add the sample preservatives to the FRB sample bottles, fill with reagent
water, and ship the FRBs with the sampling kits. Do not open FRBs in the field;
FRBs must remain sealed until analysis.
8.2.2 Use the same procedure to prepare sample containers for both FRBs and field
samples. Whenever possible, the same lots of ascorbic acid and maleic acid must be
used for the Field Reagent Blanks as for the field samples.
8.3 FIELD DUPLICATES - At a minimum, collect all samples in duplicate. If the samples will
be analyzed using a vial autosampler, collect additional Field Duplicates to fulfill QC
requirements for LFSMs, and LFSMDs (at least three identical samples). Collect additional
duplicate samples if separate analysis in SIM mode is anticipated.
8.4 SAMPLE SHIPMENT AND STORAGE - Samples must be chilled during shipment and
must not exceed 10 °C during the first 48 hours after collection. Samples must be confirmed
to be at or below 10 °C when they are received at the laboratory. In the laboratory, samples
must be stored at or below 6 °C, protected from light, and isolated from ambient sources of
VOCs. When resident in the autosampler, samples must be held at 10 °C or lower. Samples
must not be frozen.
8.5 SAMPLE HOLDING TIMES - Analyze samples as soon as possible. Samples that are
collected and stored as described in Section 8.1 and 8.4 must be analyzed within 14 days of
collection.
524.3-16
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9. QUALITY CONTROL
QC requirements include the Initial Demonstration of Capability and ongoing QC requirements.
This section describes each QC parameter, its required frequency, and the performance criteria that
must be met in order to satisfy EPA quality objectives. The QC criteria discussed in the following
sections are summarized in Section 17, Tables 15 and 16. These QC requirements are considered
the minimum acceptable QC criteria. Laboratories are encouraged to institute additional QC
practices to meet their specific needs. Compliance with the requirements of the IDC must be
demonstrated for each analyte that the laboratory intends to report using full scan MS, and for each
analyte that the laboratory intends to report in the SIM or SIS detection mode.
9.1 METHOD MODIFICATIONS - The analyst is permitted to select purge-and-trap and GC
conditions appropriate for the available instrumentation. However, five key parameters are
restricted to prescribed ranges. These ranges are summarized in the table below. If the
chosen parameters fall within the "recommended" ranges, the laboratory may proceed with
the IDC. If values outside the "recommended" ranges are selected for any one of these five
parameters, the laboratory must demonstrate equivalent performance in accordance with the
guidelines provided in Section 9.4, and then the analyst must repeat the procedures of the
IDC. However, values for the five key parameters must never exceed the "allowable" ranges
listed in the table below. In addition, sample size cannot be varied from the 5-mL volume
prescribed in this method. All other parameters including the remaining concentrator
conditions, GC conditions and MS conditions may be varied without restriction.
Parameter
Sample temperature
Purge flow rate
Purge volume
Desorb time
Purge volume + dry purge volume
Recommended
Minimum
Ambient
40 mL/min
360 mL
1 min
360 mL
Maximum
40 °C
80 mL/min
520 mL
2 min
720 mL
Allowable
Minimum
Ambient
20 mL/min
240 mL
0.5 min
240 mL
Maximum
60 °C
200 mL/min
680 mL
4 min
880 mL
9.2
NOTE: Three commercially available purge-and-trap concentrators, varying in design and
water management systems, were evaluated to determine these minimum and maximum
parameter settings. The "recommended" values provided equivalent response factors and
internal standard areas within the ranges specified in the table. The "allowable" limits
resulted in a wider variation in response factors, particularly for those analytes with low purge
efficiencies; however, operation within this range may be appropriate for limited analyte lists
and other concentrator designs. Sample temperature is limited to 60 °C to avoid acid-
catalyzed decomposition of method analytes. See Table 2 in Section 17 for typical values for
purge-and-trap parameters.
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
meet the calibration requirements outlined in Section 10. The IDC must be completed for
each concentrator and trap design. For example, if dual concentrators are interfaced to a
single GC/MS, perform the IDC for each system. If a new trap is installed with sorbent
materials different from the original trap, repeat the IDC. Requirements for the IDC are
described in the following sections and are summarized in Table 15.
524.3-17
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9.2.1 DEMONSTRATION OF LOW SYSTEM BACKGROUND - Analyze an LRB.
Confirm that the blank is free of contamination as defined in Section 9.3.1.
NOTE: The method must be checked for carryover by analyzing an LRB
immediately following the highest calibration standard. If this LRB does not meet the
criteria outlined in Section 9.3.1, then carryover is present and the cause must be
identified and eliminated.
9.2.2 DEMONSTRATION OF PRECISION - Prepare and analyze seven replicate LFBs.
Fortify these samples near the midrange of the initial calibration curve. The method
preservation reagents must be added to the LFBs as described in Section 8.1. The
percent relative standard deviation (RSD) of the concentrations of the replicate
analyses must be <20% for all method analytes.
n / ™ r.^ Standard Deviation of Measured Concentrations , ^
% RSD = xWO
Average Concentration
9.2.3 DEMONSTRATION OF ACCURACY - Calculate the average percent recovery
using the same set of replicate data generated for Section 9.2.2. The average recovery
of the replicate analyses must be within +20% of the true value.
.. _, Average Measured C oncentrati on
% Recovery = xWO
Fortified Concentration
9.2.4 MINIMUM REPORTING LEVEL (MRL) CONFIRMATION - Establish a target
concentration for the MRL based on the intended use of the data. The lowest
calibration standard used to establish the initial calibration (as well as the low-level
Continuing Calibration Check) 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 the MRL following the procedure outlined below.
NOTE: Method analytes that are consistently present in the background (e.g.,
methylene chloride, TEA) should be reported as detected in field samples only after
careful evaluation of the background levels. In such cases, an MRL must be
established at a value no less than three times the standard deviation of the mean LRB
concentration or three times the mean LRB concentration, whichever is greater. The
MRL must be calculated over an extended time period to reflect variability in the
blank measurements. This guidance is intended to minimize the occurrence of
reporting false positive results.
9.2.4.1 Fortify and analyze seven replicate LFBs at or below the proposed MRL
concentration. The LFBs must contain the method preservatives as
specified in Section 8.1. 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
HRPIR = 3.9638
524.3-18
-------
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 +_ HRPIR) meet the upper and lower recovery limits as
shown below.
The Upper PIR Limit must be <150% recovery.
Mean + HRPJR
— x 100 < 150%
Fortified Concentration
The Lower PIR Limit must be >50% recovery.
Mean - HRPTa
PIR -xlOO>50%
Fortified Concentration
9.2.4.3 The MRL is validated if both the Upper and Lower PIR Limits meet the
criteria described above. If these criteria are not met, the MRL has been set
too low and must be confirmed again at a higher concentration.
NOTE: These equations are only valid for seven replicate samples.
9.2.5 QUALITY CONTROL SAMPLE (QCS) - Analyze a mid-level Quality Control
Sample (Sect. 9.3.10) to confirm the accuracy of the primary calibration standards.
9.2.6 DETECTION LIMIT DETERMINATION (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 ascertain whether DL determination is required based upon the
intended use of the data.
Analyses for this procedure must be done over at least three days. Prepare at least
seven replicate LFBs. Fortify the LFBs at a concentration estimated to be near the
DL. This fortification level may be estimated by selecting a concentration at two to
five times the noise level. The method preservatives must be added to the samples as
described in Section 8.1. Process the seven replicates through all steps of Section 11.
NOTE: If a data set used for the MRL confirmation step of the IDC 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 = Sx t(n-l,l-a = 0.99)
524.3-19
-------
where
t(n-i,i-a = 0.99)= Student's t value for the 99% confidence level with n-1 degrees of
freedom (for seven replicate determinations, the Student's t value
is 3.143 at a 99% confidence level),
n = number of replicates, and
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 procedures that
must be followed when processing and analyzing field samples. Table 16 summarizes these
requirements.
9.3.1 LABORATORY REAGENT BLANK (LRB) - Analyze an LRB with each Analysis
Batch. The LRB must contain the method preservatives, the internal standards, and
surrogate analytes at the same concentration used to fortify all field samples and
calibration standards. Background from method analytes or contaminants that inter-
fere with the measurement of method analytes must be less than l/2 the MRL. If the
method 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 that yielded a positive result. Subtracting LRB values from sample results
is not permitted.
NOTE: Although quantitative data below the MRL may not be accurate enough for
data reporting, such data are useful in determining the magnitude of background
interference. Therefore, blank contamination levels may be estimated by
extrapolation when the concentration is below the MRL.
NOTE: After analysis of a sample in which method analytes exceed the calibration
range, one or more LRBs must be analyzed (to detect potential carryover) until the
system meets the LRB acceptance criteria. If this occurs during an automated
sequence, examine the results of samples analyzed following the sample that
exceeded the calibration range. If the analytes that exceeded the calibration range in
the previous sample are detected at or above the MRL, these samples are invalid. If
the affected analytes do not exceed the MRL, these subsequent samples are valid.
THMs are excluded from this requirement.
NOTE: The LRB test in the IDC may be particularly difficult to pass for compounds
analyzed using the SIM detection mode. For anaytes monitored in SIM mode, the
laboratory should restrict the high calibration point to 1.0 or 2.0 |ig/L, and consider
other techniques such as using a dedicated sparge vessel and more aggressive recycle
parameters. If possible, select MRLs that allow monitoring goals to be achieved, but
that are well above typical blank values.
9.3.2 CONTINUING CALIBRATION CHECK (CCC) - Analyze CCC standards at the
beginning of each Analysis Batch, after every ten field samples, and at the end of the
Analysis Batch. See Section 10.2 for concentration requirements and acceptance
criteria.
524.3-20
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9.3.3 LABORATORY FORTIFIED BLANK (LFB) - Because this method utilizes
procedural calibration standards, which are fortified reagent waters, there is no
difference between the LFB and the CCC standards. Consequently, the analysis of a
separate LFB is not required as part of the ongoing QC; however, the term "LFB" is
used for clarity in the IDC.
9.3 .4 MS TUNE CHECK - The procedure for conducting the MS Tune Check for BFB is
found in Section 10.1.1. Acceptance criteria for the MS Tune Check are summarized
in Section 17, Table 1. The MS Tune Check must be performed prior to establishing
and/or re-establishing an initial calibration (Sect. 10.1) and each time a major change
is made to the mass spectrometer. Daily BFB analysis is not required.
9.3.5 INTERNAL STANDARDS (IS) - The analyst must monitor the peak areas of the
internal standards in all injections of the Analysis Batch. The IS responses (peak
area) in any chromatographic run must not deviate from the response in the most
recent CCC by more than +30%, and must not deviate by more than +50% from the
average area measured during initial analyte calibration. If an IS area for a sample
does not meet these criteria, check the corresponding IS area of the most recent CCC
and proceed as follows.
9.3.5.1 If the IS criteria are met in the CCC but not the sample, reanalyze the
sample (Field Duplicate) in a subsequent Analysis Batch. If the IS area fails
to meet the acceptance criteria in the Field Duplicate, but passes in the most
recent CCC, report the sample results as "suspect/matrix."
9.3.5.2 If both the original sample and the CCC fail the IS criteria, take corrective
action beginning with an extended bake cycle for the GC column and the
concentrator trap. Area counts may decrease as the rate of water entering
the mass spectrometer exceeds the capacity of the pumping system to
remove it. Additional measures such as clipping the inlet side of the GC
column and cleaning the MS source may be indicated. Verify the integrity
of the IS solution and the fortification technique. Perform the appropriate
instrument maintenance and then reanalyze the sample (Field Duplicate) in a
subsequent Analysis Batch. If the IS area fails to meet the acceptance
criteria in the Field Duplicate, but passes in the most recent CCC, report the
sample results as "suspect/matrix."
9.3.6 SURROGATE RECOVERY - The surrogate analytes are fortified into all calibration
standards, field samples, and QC samples prior to purge-and-trap analysis. Calculate
the percent recovery (%R) for each surrogate using the following equation:
( k\
%R= — xlOO
where
A = calculated surrogate concentration for the QC or field sample, and
B = fortified concentration of the surrogate.
524.3-21
-------
9.3.6.1 Surrogate recovery must be in the range of 70% to 130%. When surrogate
recovery from a field sample, blank, or QC sample is less than 70% or
greater than 130%, check: 1) calculations to locate possible errors, 2) the
integrity of the surrogate analyte solution and the fortification technique,
3) contamination, and 4) instrument calibration. Also, see corrective action
options in Section 9.3.5.2. Correct the problem and reanalyze the sample in
a subsequent Analysis Batch using the appropriate Field Duplicate.
9.3.6.2 If the repeat analysis meets the surrogate recovery criterion, only report data
for the Field Duplicate.
9.3.6.3 If the Field Duplicate fails the surrogate recovery criterion after corrective
action has been taken, report all data for that sample as "suspect/surrogate
recovery."
9.3.7 LABORATORY FORTIFIED SAMPLE MATRIX (LFSM) - Within each Analysis
Batch, analyze a minimum of one LFSM. The native concentrations of the analytes
in the sample matrix must be determined in a separate aliquot and subtracted from the
measured values in the LFSM. If a variety of different sample matrices are analyzed
regularly, for example, drinking water from ground water and surface water sources,
performance data must be collected for each source.
9.3 .7. 1 Prepare the LFSM by fortifying a Field Duplicate with an appropriate
amount of an analyte PDS (Sect. 7.3.2). Select a spiking concentration that
is greater than or equal to the native background concentration, if known.
Selecting a duplicate aliquot of a sample that has already been analyzed aids
in the selection of an appropriate spiking level. If this is not possible, use
historical data and rotate through low, medium, and high calibration
concentrations when selecting a fortifying concentration.
NOTE: If the presence of disinfection byproducts (DBFs) (e.g., THMs)
precludes selection of an appropriate fortification level for the majority of
the method analytes, the DBFs may be ignored. For example, if the analyst
wishes to estimate accuracy and precision at 1.0 |ig/L, and chloroform is
present in the native matrix at 10 |ig/L, chloroform is fortified at only 10%
of its native concentration. In such cases, recovery results for the DBFs may
fail the acceptance criteria for LFSM. Appropriately qualify the QC result
when this occurs. If the laboratory is analyzing specifically for DBFs, or
does not wish to exclude them, select a fortification level based on the DPB
concentrations in the native sample such that the final DBF results fall
within the calibration range.
9.3.7.2 Calculate the percent recovery (%R) using the equation:
C
524.3-22
-------
where
A = measured concentration in the fortified sample,
B = measured concentration in the unfortified sample, and
C = fortification concentration.
9.3.7.3 Recoveries for samples fortified at concentrations near or at the MRL
(within a factor of two times the MRL concentration) must be within +50%
of the true value. Recoveries for samples fortified at all other concentrations
must be within +30% of the true value. 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, the recovery is judged matrix biased.
The result for that analyte in the unfortified sample is labeled
"suspect/matrix."
NOTE: In order to obtain meaningful percent recovery results, correct the
measured values in the LFSM and LFSMD for the native levels in the
unfortified samples, even if the native values are less than the MRL. This
situation and the LRB are the only permitted uses of analyte results below
the MRL.
9.3.8 FIELD DUPLICATE OR LABORATORY FORTIFIED SAMPLE MATRIX
DUPLICATE (FD or LFSMD) - Within each Analysis Batch, analyze a minimum of
one Field Duplicate or one Laboratory Fortified Sample Matrix Duplicate. If method
analytes are not routinely observed in field samples, analyze an LFSMD rather than
anFD.
9.3.8.1 Calculate the relative percent difference (RPD) for duplicate measurements
(FDi and FD2) using the equation:
RPD
-FD2
(FD^FDj/2
:100
9.3.8.2 RPDs for Field Duplicates must be <30%. Greater variability may be
observed when Field Duplicates have analyte concentrations that are near or
at the MRL (within a factor of two times the MRL concentration). At these
concentrations, Field Duplicates must have RPDs that are <50%. If the
RPD of an analyte falls outside the designated range, and the laboratory
performance for the analyte is in control in the CCC, the precision is judged
matrix influenced. The result from the unfortified sample is labeled
"suspect/matrix."
9.3.8.3 If an LFSMD is analyzed instead of a Field Duplicate, calculate the RPD for
the LFSM and LFSMD using the equation:
LFSM-LFSMD
(LFSM + LFSMD)/2
524.3-23
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9.3.8.4 RPDs for duplicate LFSMs must be <30%. Greater variability may be
observed when fortified LFSMs have analyte concentrations that are near or
at the MRL (within a factor of two times the MRL concentration). LFSMs
at these concentrations must have RPDs that are <50%. If the RPD of an
analyte falls outside the designated range, and the laboratory performance
for that analyte is in control in the CCC, the precision is judged matrix
influenced. The result from the unfortified sample is labeled
"suspect/matrix."
9.3.9 FIELD REAGENT BLANK (FRB) - FRBs must be analyzed if compounds other
than commonly occurring DBFs, such as THMs, are detected in field samples.
Qualify the result for any analyte that is detected in both a field sample and in the
associated FRB as "probable contribution from shipping and storage." Subtracting
FRB values from sample results is not permitted.
9.3.10 QUALITY CONTROL SAMPLE (QCS) - A QCS must be evaluated as part of the
IDC, and repeated at least quarterly. Fortify the QCS near the midpoint of the
calibration range. The acceptance criteria for the QCS are the same as the mid-level
and high-level CCCs (Sect. 10.2.1). If the accuracy for any analyte fails the recovery
criterion, check the standard preparation process, stock standard sources, and the
purity of neat materials used to prepare the stock standards to locate and correct the
problem.
9.4 METHOD MODIFICATION QC REQUIREMENTS - The analyst is permitted to modify the
five key purge-and-trap parameters (sample temperature, purge flow rate, purge volume,
desorb time, and dry purge volume) selecting values outside of the "recommended" ranges
(Sect. 9.1). The analyst is not permitted to modify sample collection and preservation, change
the QC requirements of the method, or increase the sample volume above 5 mL. Do not add
or delete QC compounds from the list prescribed in the method: ISs (Sect. 7.2.1) and
surrogates (Sect. 7.2.2). Each time method modifications are proposed for one of the five key
parameters; that is, outside of the "recommended" minimum and maximum, the laboratory
must confirm that the new parameters provide acceptable method performance as defined in
the following subsections.
9.4.1 The new parameters must fall within the "allowable" minimum and maximum limits
specified in Section 9.1. Values outside these limits are not permitted under any
circumstances.
9.4.2 Perform an initial calibration procedure (Sect. 10.1) for the method analytes that the
laboratory intends to report using conditions that fall within the "recommended"
ranges as presented in Section 9.1. Determine relative response factors (RRF) for
each analyte averaged over the entire calibration range.
Analyte (area) x IS (|ig/L)
KJvr — T T
IS (area) x Analyte (|ig/L)
9.4.3 Optimize the purge-and trap system using the proposed method modifications.
Analyze three mid-level calibration standards and calculate mean RRFs for each
524.3-24
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method analyte. If all of the response factors observed using the modified conditions
are >70% of the initial calibration response factors obtained using the
"recommended" method conditions (Sect. 9.4.2), then the modified method
parameters are permitted. Repeat the procedures of the IDC (Sect. 9.2) employing the
modified parameters.
9.4.4 The analyst is also required to evaluate and document 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 in the IDC, which is conducted in reagent water, could fail
ongoing method QC requirements in real matrices. If, for example, the laboratory
analyzes drinking water from both surface and ground water 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 ground water [e.g., 250 mg/L as calcium carbonate (CaCO3)
equivalent, or greater].
9.4.5 The results of Sections 9.4.3 and 9.4.4 must be appropriately documented by the
analyst and should be independently assessed by the laboratory's QA officer prior to
analyzing field samples.
9.4.6 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. 9.3.7), LFSMD (Sect. 9.3.8), CCCs (Sect. 9.3.2), and the IS area
counts (Sect. 9.3.5). If repeated failures are noted, the modification must be
abandoned.
10. CALIBRATION AND STANDARDIZATION
Demonstration and documentation of acceptable analyte calibration is required before performing
the IDC (Sect. 9.2) and prior to analyzing field samples. Verification of the MS calibration and the
initial calibration must be repeated each time a major instrument modification or maintenance is
performed.
NOTE: For tandem concentrators or older systems that utilize multiple sparging vessels and/or
traps, a separate calibration and all required QC samples must be analyzed on each sample path. In
addition, a qualitative marker compound must be added to all samples to uniquely identify the
sample path, and ensure that samples are matched to the proper calibration and QC results. For
example, fluorobenzene could be added to all samples analyzed on the second sample path of a
tandem concentrator system.
10.1 PURGE AND TRAP GC/MS OPTIMIZATION AND INITIAL CALIBRATION - An initial
calibration requires optimizing purge-and-trap and GC/MS conditions, confirming that the
instrument meets the BFB tune check criteria, and the preparation and analysis of at least
seven calibration standards to determine the calibration curve. Calibration must be performed
using peak areas and the internal standard technique. Calibration using peak heights and
external standard calibration are not permitted.
524.3-25
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10.1.1 MS TUNE/MS TUNE CHECK- Calibrate the mass and abundance scales of the MS
utilizing calibration compounds and procedures recommended by the manufacturer
with any modifications necessary to meet tuning requirements. Introduce BFB (Sect.
7.5) into the GC/MS system. Acquire a mass spectrum using the same scan range
employed for full scan sample analyses. Use a single spectrum at the apex of the
BFB peak, an average spectrum of the three highest points of the peak, or an average
spectrum across the entire peak to evaluate the performance of the system.
Appropriate background subtraction is allowed; however, the background scan(s)
must be chosen from the baseline prior to or after elution of the BFB peak. If the
BFB mass spectrum does not meet all criteria in Table 1, the MS must be retuned to
meet all criteria before proceeding with the initial calibration.
10.1.2 PURGE-AMD-TRAP CONDITIONS - Establish purge-and-trap parameters
following the manufacturer's recommendations. Make sure that the sample
temperature, purge flow rate, purge volume, desorb time, and dry purge volume are
within the "allowable" ranges specified in section 9.1. Optimize purge-and-trap
parameters to maximize purging efficiency and minimize the transmission of water to
the GC/MS system.
10.1.3 GC CONDITIONS - Establish GC operating conditions appropriate for the GC
column dimensions by optimizing the split ratio and temperature program. Generally,
the required split ratio is inversely proportional to column diameter. The user must
balance the need to transfer enough of the method analytes to achieve the desired
MRLs and the need to reduce water transmission from the purge-and-trap
concentrator. The split ratio will also affect the chromatographic peak profile of the
most volatile method analytes, commonly referred to as "gases." Sufficient
resolution and symmetrical peak profiles with minimal tailing for these analytes must
be achieved to enable accurate and precise integration. A mass chromatogram of the
gases obtained during method development is provided in Figure 1. The GC program
must be optimized to provide adequate resolution of the method analytes as defined in
the following subsections.
10.1.3.1 If possible, optimize chromatographic conditions such that a unique
quantitation ion is available for each analyte that is free from interference
due to an identical fragment ion in any co-eluting (or overlapping) peak(s).
10.1.3.2 If a unique quantitation ion of sufficient intensity to set the desired MRL is
not available, overlap with an identical ion from an overlapping analyte is
permitted, providing that at least a 50% valley between the mass peaks is
achieved.
10.1.4 FULL SCAN MS CONDITIONS - Select a scan range that allows the acquisition of
a mass spectrum for each of the method analytes, which includes all of the major
fragments mass-to-charge ratio (m/z) 35 and above. However, during elution of the
water/carbon dioxide peak, the analyst is permitted to begin the scan at m/z 45 to
eliminate the appearance of these matrix components in the baseline.
10.1.5 SIM MS CONDITIONS - In SIM mode, choose one primary quantitation ion and at
least one secondary ion. If possible, select a second confirmation ion. Additional
524.3-26
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ions may be monitored that demonstrate a unique characteristic in the mass spectrum
such as a halogen cluster. Verify that the primary ion is free from interference (Sect.
10.1.3.1 and Sect. 10.1.3.2) due to an identical fragment ion in any overlapping
peak(s). If the chromatogram is divided into SIM windows (also termed segments or
periods), the laboratory must ensure that each method analyte elutes entirely within
the proper window during each Analysis Batch. Make this observation by viewing
the mass chromatogram of the quantitation ion for each SIM analyte in the CCC
analyzed at the beginning and end of each Analysis Batch. This requirement does not
preclude continuous operation by sequencing multiple Analysis Batches; however,
the entire Analysis Batch is invalid if one or more analyte peaks drift outside of
designated SIM windows in either of these CCCs.
10.1.6 ALTERNATING FULL AND SIM SCAN MODES - Alternating full and SIM scan
functions during a single sample acquisition is permitted if the minimum number of
scans across each GC peak acquired in this mode is maintained, i.e., six scans as
specified in Section 6.9.4 in each full and SIM scan modes.
10.1.7 CALIBRATION STANDARDS - Prepare a set of at least seven calibration standards
as described in Section 7.4. The lowest concentration of the calibration standards
must be at or below the MRL. The MRL must be confirmed using the procedure
outlined in Section 9.2.4 after establishing the initial calibration. Additionally, field
samples must be quantified using a calibration curve that spans the same
concentration range used to collect the IDC data (Sect. 9.2), e.g., analysts are not
permitted to use a restricted calibration range to meet the IDC criteria and then use a
larger dynamic range during analysis of field samples.
10.1.8 CALIBRATION - Calibrate the GC/MS system using peak areas and the internal
standard technique. Fit the calibration points with either a linear or a quadratic
regression (response vs. concentration). Weighting may be used. The GC/MS
instrument used during method development was calibrated using inverse
concentration-weighted quadratic curves. Suggested internal standard assignments
and quantitation ions for each method analyte evaluated in full scan mode are
presented in Table 4. Suggested internal standard assignments and quantitation ions
for each method analyte evaluated in SIM mode are presented in Table 5.
NOTE: Because the surrogate analytes are added at a single concentration level to the
calibration standards, calibrate for each surrogate using an average response factor.
10.1.9 FORCING ZERO - Forcing the calibration curve through the origin is not
recommended. However, zero must be forced for method analytes (e.g., common
laboratory contaminants) if they are consistently detected in the Laboratory Reagent
Blanks. Forcing zero allows for a better estimate of the background level of blank
contaminants. An accurate estimate of background contamination is necessary to set
MRLs for method analytes when blank levels are problematic (Sect. 9.2.4).
10.1.10 CALIBRATION ACCEPTANCE CRITERIA - The initial calibration is validated by
calculating the concentration of the analytes for each of the analyses used to generate
the calibration curve by use of the regression equations. Calibration points that are
-------
points must calculate to be within +30% of their true value. If these criteria cannot be
met, the analyst will have difficulty meeting ongoing QC criteria. In this case,
corrective action is recommended such as reanalyzing the calibration standards,
restricting the range of calibration, or performing instrument maintenance.
10.2 CONTINUING CALIBRATION CHECKS (CCCs) - Analyze a CCC to verify the initial
calibration at the beginning of each Analysis Batch, after every tenth field sample, and at the
end of each Analysis Batch. The beginning CCC for each Analysis Batch must be at or below
the MRL. This CCC verifies instrument sensitivity prior to the analysis of samples. Alternate
subsequent CCCs between the remaining calibration levels.
10.2.1 Calculate the concentration of each analyte in the CCC. Each analyte in the CCC
fortified at
-------
vent any residual air while adjusting the sample volume to 5 mL. Add the internal
standard/surrogate analyte PDS to the sample through the syringe valve. Immediately load
the sample into the sparging vessel.
NOTE: Do not store samples in syringes or prepare QC samples by filling two syringes. A
second VOA vial (i.e., a Field Duplicate) is required as a means of ensuring that a back up
sample is available, and for preparing FD, LFSM and LFSMD QC samples.
11.1.1 PREPARATION OF LFSM and LFSMD: SYRINGE METHOD - Three 40-mL
vials (FDs) are required for a sample and its associated LFSM and LFSMD. Fortify
two of the samples using an analyte PDS of appropriate concentration by injecting
through the syringe valve. Add the internal standards and surrogates as directed in
Section 11.1.
11.1.2 FIELD DUPLICATE: SYRINGE METHOD - Fill a 5-mL syringe with the selected
Field Duplicate, and fortify with internal standards and surrogates. Analyze FDs at
the frequency specified in Section 9.3.8.
11.2 SAMPLE PREPARATION: VIAL AUTOSAMPLER METHOD - Activate the cooling
mechanism of the refrigerated autosampler and allow it to reach the temperature set point.
Remove samples from cold storage and immediately load them into the vial autosampler.
Prepare the IS/surrogate fortification solution at a concentration appropriate for the
automated standard addition device.
11.2.1 PREPARATION OF LFSM and LFSMD FOR VIAL AUTOSAMPLERS - Three
40-mL vials (FDs) are required for a sample and its associated LFSM and LFSMD.
Fortify two of the samples using an analyte PDS of appropriate concentration by
puncturing the septa of each vial with a syringe. Allow time for the compounds to
disperse homogeneously within the sample. Assume that the sample volume is 40
mL or estimate the typical volume of a 40-mL vial in use at your laboratory.
Fortification may be accomplished by use of a standard addition module if the
autosampler is so equipped.
11.2.2 FDs FOR VIAL AUTOSAMPLERS - Load the appropriate Field Duplicate vial into
the autosampler. Analyze FDs at the frequency specified in Section 9.3.8.
11.3 PURGE-AND-TRAP ANALYSIS
11.3.1 Establish purge-and-trap and GC/MS operating conditions per the guidance in
Section 10.1.
11.3.2 Bake the concentrator trap and GC column to remove contaminants that may have
collected in the system. This step is especially important if the analytical system has
been idle for more than a few hours.
11.3.3 Initiate the purge cycle and autosampler sequence. After the purge cycle, preheat the
trap as recommended by the manufacturer. Start the data acquisition at the
beginning of the desorb cycle. Bake the trap, and rinse the sparging vessel and
autosampler delivery lines using settings optimized to minimize sample carryover.
524.3-29
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NOTE: The method preservatives cause the water column in the sparging vessel to
appear effervescent during the purge cycle. This is normal and no adverse effects
occur as a result of the effervescence.
11.4 THE ANALYSIS BATCH - Establish a valid initial calibration following the procedures
outlined in Section 10.1 and confirm that the calibration is still valid by analyzing a CCC at
or below the MRL as described in Section 10.2. Alternately, verify that an existing
calibration, established for a previous Analysis Batch, is valid by analyzing a CCC at or
below the MRL. Next, analyze an LRB. Continue the Analysis Batch by analyzing aliquots
of field and QC samples at appropriate frequencies (Section 9.3), employing the optimized
conditions used to acquire the initial calibration. Analyze a mid- or high-level CCC after
every ten field samples and at the end each Analysis Batch.
NOTE: Each Analysis Batch must begin with the analysis of a CCC at or below the MRL
for each analyte that the laboratory intends to report, followed by the analysis of an LRB.
This is true whether or not an initial calibration is analyzed. After 20 field samples, the low-
level CCC and the LRB must be repeated to begin a new Analysis Batch. The acquisition
start time of the mid-level CCC at the end of the Analysis Batch must be within 24 hours of
the acquisition start time of the low-level CCC at the beginning of the Analysis Batch.
Multiple Analysis Batches within a 24-hour period are permitted. Do not count QC samples
(LRBs, FRBs, FDs, LFSMs, LFSMDs) when calculating the frequency of CCCs that are
required during an Analysis Batch.
12. DATA ANALYSIS AND CALCULATIONS
12.1 COMPOUND IDENTIFICATION - Establish an appropriate retention time window for each
analyte to identify them in QC and field sample chromatograms. Base this assignment on
measurements of actual retention time variation for each compound in standard solutions
analyzed on the GC/MS over the course of time. The suggested variation is plus or minus
three times the standard deviation of the retention time for each compound for a series of
injections. The injections from the initial calibration and from the IDC (Sect. 9.2) may be
used to calculate the retention time window. However, the experience of the analyst should
weigh heavily on the determination of an appropriate range.
12.1.1 At the conclusion of data acquisition, use the same software settings established
during the calibration procedure to identify peaks of interest in the predetermined
retention time windows. Initially, identify an analyte by comparison of its retention
time with that of the corresponding analyte peak in a recent initial calibration
standard or CCC.
12.1.2 Some GC/MS programs use spectra matching criteria when collecting data in full
scan mode based on the comparison of field sample spectra (after background
subtraction if necessary) to a reference spectrum in the user-created database. This
database should be created prior to conducting the IDC from spectra obtained for a
mid-level to high-level calibration standard and updated as necessary. If available,
this feature may be utilized as a secondary identification routine; however, the
primary criterion must be based on the analyte retention time.
524.3-30
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12.2 COMPOUND CONFIRMATION FULL SCAN MODE - In general, all ions that are present
above 30 percent relative abundance in the mass spectrum of the user-generated database
must be present in the mass spectrum of the sample component and must agree within an
absolute 20 percent of the relative abundance in the reference spectrum. For example, if an
ion has a relative abundance of 30 percent in the standard spectrum, its abundance in the
sample spectrum must be in the range of 10 to 50 percent. Some ions, particularly the
molecular ion, are of special importance, and should be evaluated even if they are below 30
percent relative abundance.
NOTE: Compound identification is more challenging when sample components are not
resolved chromatographically and produce mass spectra containing ions contributed by more
than one analyte. When GC peaks obviously represent more than one sample component
(i.e., broadened peak with shoulder(s) or valley between two or more maxima), appropriate
analyte spectra and background spectra can be selected by examining individual spectra
profiles during the peak to determine the characteristic ions. When analytes co-elute (i.e.,
only one GC peak is apparent), the identification criteria may be met but each analyte
spectrum will contain extraneous ions contributed by the co-eluting compound.
12.3 COMPOUND CONFIRMATION SIM MODE - In SIM mode, each confirmation ion should
be present. For each analyte identified by retention time, the abundance of the confirmation
ions relative to the quantitation ion should agree within an absolute 20 percent of the relative
abundance in the spectrum taken from a recent calibration standard analyzed in SIM mode.
For example, if an ion has a relative abundance of 30 percent in the calibration standard, its
abundance in the sample spectrum should be in the range of 10 to 50 percent.
12.4 COMPOUND QUANTITATION - Calculate analyte concentrations using the multipoint
calibration established in Section 10.1. Report only those values that fall between the MRL
and the highest calibration standard.
12.4.1 Calculations must use all available digits of precision, but final reported
concentrations should be rounded to an appropriate number of significant figures (one
digit of uncertainty); this is typically two, and not more than three, significant figures.
12.4.2 Prior to reporting data, the chromatograms must be reviewed for incorrect peak
identification or improper integration.
12.4.3 Prior to reporting data, the laboratory is responsible for assuring that QC
requirements have been met and that any appropriate qualifier is assigned.
12.5 EXCEEDING THE CALIBRATION RANGE - The analyst must not extrapolate beyond the
established calibration range. If an analyte result exceeds the range of the initial calibration
curve, dilute the Field Duplicate using reagent water containing the method preservatives.
Re-inject the diluted sample. Incorporate the dilution factor into final concentration
calculations. The resulting data must be annotated as a dilution, and the reported MRLs must
reflect the dilution factor.
524.3-31
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13. METHOD PERFORMANCE
References to specific brands or catalog numbers are included as examples only and do not imply
endorsement of the product. These references do not preclude the use of other vendors or supplies.
13.1 PRECISION, ACCURACY AND DETECTION LIMITS - The method performance data
presented in Section 17 were collected using a Tekmar Stratum Purge and Trap Concentrator
with a Tekmar AQUATek 70 Vial Autosampler interfaced to an Agilent 6890 Plus GC and an
Agilent 5973 MS. Table 2 lists the purge-and-trap conditions used to gather the method
performance data presented in Section 17. GC/MS conditions for the Agilent system are
presented in Table 3. Table 4 presents the quantitation ions employed in full scan mode
appropriate for the Restek Rtx®-VMS column (no interference from overlapping peaks) for
each analyte, internal standard, and surrogate analyte, suggested internal standard
assignments, and observed retention times associated with the method performance results.
Table 5 lists the method analytes for which method performance data were collected in the
SIM mode; primary quantitation ions and internal standard references are provided. Single
laboratory LCMRLs and DLs determined in full scan mode are listed in Table 6. Single
laboratory precision and accuracy data obtained in full scan mode are presented for three
water matrices: reagent water (Table 7), chlorinated (finished) ground water (Table 8), and
chlorinated (finished) surface water (Table 9). LCMRLs and DLs obtained in SIM mode for
selected method analytes are presented in Table 10. Single laboratory precision and accuracy
data were collected in SIM mode for selected analytes in three water matrices: reagent water
(Table 11), chlorinated (finished) ground water (Table 12), and chlorinated (finished) surface
water (Table 13). Figure 1 depicts an extracted ion chromatogram of the method analytes that
are gases at room temperature. Figures 2 and 3 are total ion chromatograms of the method
analytes in reagent water and drinking water, obtained under the conditions employed during
method development.
13.2 SAMPLE STORAGE STABILITY STUDIES - An analyte storage stability study was
conducted by fortifying the analytes (20 |ig/L of each analyte) into a chlorinated surface water
that was collected, preserved, and stored as described in Section 8. The average recovery of
triplicate analyses, conducted on Days 0, 7, 14 are presented in Table 14.
13.3 SECOND LABORATORY DEMONSTRATION - The performance of this method was
demonstrated by five outside laboratories, with results similar to those reported in Section 17.
The authors wish to acknowledge Tekmar (Teledyne Technologies Co.), OI Analytical, EST
Analytical, Varian, Inc., and Underwriters Laboratories, Inc., for their contribution to the
development of this method.
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/x7432.xml.
524.3-32
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15. WASTE MANAGEMENT
15.1 The analytical procedures described in this method generate relatively small amounts of waste
since only small amounts of reagents and solvents 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 fume hoods and bench operations. In addition, 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. Additional waste
management information can be found in "Laboratory Waste Minimization and Pollution
Prevention," Copyright © 1996 Battelle Seattle Research Center, which can be located at
http://www.p2pavs.org/ref/01/text/00779/ch05.htm.
16. REFERENCES
1. Winslow, S. D.; Pepich, B. V.; Martin, J. J.; Hallberg, G. R.; Munch D. J.; 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. Occupational Exposures to Hazardous Chemicals in Laboratories, 29 CFR 1910.1450,
Occupational Safety and Health Administration.
4. Safety in Academic Chemistry Laboratories; American Chemical Society Publication;
Committee on Chemical Safety: 7th Edition, 2003.
5. Standard Practice for Sampling Water from Closed Conduits; ASTM Annual Book of
Standards, Section 11, Volume 11.01, D3370-07; American Society for Testing and Materials:
Philadelphia, PA, 2007.
524.3-33
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17. TABLES, DIAGRAMS, FLOWCHARTS, AND VALIDATION DATA
The conditions listed in the tables of this section were used to collect method performance data at EPA.
They do not represent any form of guidance for acceptable parameter settings. Refer to the relevant
sections of the method for guidance on optimizing and selecting purge-and-trap and GC/MS conditions.
TABLE 1. 4-BROMOFLUOROBENZENE (BFB) MASS INTENSITY CRITERIA
m/z
95
96
173
174
175
176
177
Required Intensity (relative abundance)
Base peak, 100% relative abundance
5to9%ofm/z95
Less than 2% of m/z 174
Greater than 50% of m/z 95
5 to 9% of m/z 174
Greater than 95% but less than 105% of m/z
174
5 to 10% of m/z 176
TABLE 2. PURGE AND TRAP CONDITIONS USED FOR METHOD PERFORMANCE
RESULTS
Parameter
Sample volume
Sample purge temperature
Trap
Purge cycle
Condenser purge temperature
Dry purge
Desorb preheat temperature
Desorb cycle
Bake rinse cycles
Bake cycle
Conditions"
5mL
Ambient
Tekmar #9 (proprietary sorbent materials)
40 mL/min for 1 1 min
20 °C
100 mL/min for 2 min
250 °C
260 °C for 1.0 min
Sparging vessel and autosampler sample path rinsed twice
280 °C for 4 min @ 200 mL/min
The chromatograms presented in Figures 2 and 3 were obtained under these conditions.
524.3-34
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TABLE 3. GAS CHROMATOGRAPHY/MASS SPECTROMETRY (GC/MS) CONDITIONS
FOR METHOD PERFORMANCE RESULTS
Parameter
Column
Inlet liner
Inlet conditions
GC temperature program
Solvent delay
MS source temperature
MS quadrupole temperature
GC/MS interface
Full scan window 1
Full scan window 2
SIM parameters
Conditions3
Restek Rtx®-VMS 30 meter, 0.25 mm i.d., 1.4 \ua df
1-mm i.d., deactivated glass
30:1 split ratio, 200 °C, helium carrier gas, column flow rate: 0.9
mL/min
45 °C for 4.5 min, 12 °C/min to 100 °C, hold 0 min, 25 °C to 240 °C,
hold 1.32 min
1.5 min before activating filaments in the electron impact source
230 °C
150 °C
Direct, 240 °C
m/z 47 to 300 (1.5 to 2.9 min)
m/z 35 to 300 (2.9 min to 16 min)
100 msec dwell per ion, 2 to 4 ions per retention time window
The chromatograms presented in Figures 2 and 3 were obtained under these conditions.
TABLE 4. RETENTION TIMES, RECOMMENDED QUANTITATION IONS, AND
SUGGESTED INTERNAL STANDARD REFERENCES FOR FULL SCAN MODE3
Analyte
dichlorodifluoromethane
chlorodifluoromethane
chloromethane
vinyl chloride
1,3 -butadiene
bromomethane
trichlorofluoromethane
diethyl ether
1,1-dichloroethene
carbon disulfide
methyl iodide
allyl chloride
methylene chloride
trans- 1 ,2-dichloroethene
methyl acetate
methyl-t-butyl ether-J3 (surrogate #1)
methyl-t-butyl ether (MtBE)
t-butyl alcohol (TEA)
diisopropyl ether (DIPE)
1,1-dichloroethane
t-butyl ethyl ether (ETBE)
cis- 1 ,2-dichloroethene
Peak no. Fig.'s 2a, 2b, 2c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
RT
1.79
1.82
1.97
2.04
2.05
2.34
2.59
2.90
3.11
3.15
3.28
3.65
3.79
3.98
4.01
4.10
4.13
4.28
4.66
4.84
5.18
5.59
Q-Ion
85
51
50
62
54
94
101
59
96
76
142
76
84
96
43
76
73
59
45
63
59
96
ISb Reference
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
524.3-35
-------
Analyte
bromochloromethane
chloroform
carbon tetrachloride
tetrahydrofuran
1,1,1 -trichloroethane
1 , 1 -dichloropropene
1-chlorobutane
benzene
t-amyl methyl ether (TAME)
1 ,2-dichloroethane
trichloroethene
1,4-difluorobenzene (IS #1)
t-amyl ethyl ether (TAEE)
dibromomethane
1 ,2-dichloropropane
bromodichloromethane
cis- 1 , 3 -dichloropropene
toluene
tetrachloroethene
trans- 1 ,3 -dichloropropene
ethyl methacrylate
1 , 1 ,2-trichloroethane
dibromochloromethane
1 ,3 -dichloropropane
1 ,2-dibromoethane
chlorobenzene-c/5 (IS #2)
chlorobenzene
ethylbenzene
1,1, 1 ,2-tetrachloroethane
m-xylene
p-xylene
o-xylene
styrene
bromoform
isopropylbenzene
4-bromofluorobenzene (surrogate #2)
bromobenzene
n-propylbenzene
1 , 1 ,2,2-tetrachloroethane
2-chlorotoluene
1 ,3 ,5-trimethylbenzene
1 ,2,3 -trichloropropane
4-chlorotoluene
t-butylbenzene
Peak no. Fig.'s 2a, 2b, 2c
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
RT
5.85
5.96
6.12
6.17
6.22
6.38
6.45
6.70
6.86
6.97
7.44
7.49
7.75
7.96
8.09
8.18
8.94
9.22
9.65
9.70
9.87
9.87
10.04
10.14
10.27
10.75
10.76
10.79
10.82
10.92
10.92
11.29
11.33
11.36
11.55
11.78
11.87
11.88
11.95
12.01
12.03
12.05
12.14
12.28
Q-Ion
128
83
117
72
97
110
56
78
73
62
132
114
59
93
63
83
75
92
166
75
69
83
129
76
107
117
112
91
131
106
106
106
104
173
105
95
156
91
83
126
105
110
91
134
ISb Reference
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
524.3-36
-------
Analyte
pentachloroethane
1 ,2,4-trimethylbenzene
sec-butylbenzene
4-isopropyltoluene
1 ,3 -dichlorobenzene
l,4-dichlorobenzene-
-------
TABLE 6. LOWEST CONCENTRATION MINIMUM REPORTING LEVELS (LCMRLs) AND
DETECTION LIMITS (DLs) FOR FULL SCAN MODE
Analyte
dichlorodifluoromethane
chlorodifluoromethane
chloromethane
vinyl chloride
1,3 -butadiene
bromomethane
trichlorofluoromethane
diethyl ether
1,1-dichloroethene
carbon disulfide
methyl iodide
allyl chloride
methylene chloride
trans-l,2-dichloroethene
methyl acetate
methyl-t-butyl ether (MtBE)
t-butyl alcohol (TEA)
diisopropyl ether (DIPE)
1,1-dichloroethane
t-butyl ethyl ether (ETBE)
cis- 1 ,2-dichloroethene
bromochloromethane
chloroform
carbon tetrachloride
tetrahydrofuran
1,1,1 -trichloroethane
1 , 1 -dichloropropene
1-chlorobutane
benzene
t-amyl methyl ether (TAME)
1,2-dichloroethane
trichloroethene
t-amyl ethyl ether (TAEE)
dibromomethane
1,2-dichloropropane
bromodichloromethane
cis- 1 ,3 -dichloropropene
toluene
tetrachloroethene
trans- 1 , 3 -dichloropropene
ethyl methacrylate
1, 1,2-trichloroethane
dibromochloromethane
1 , 3 -dichloropropane
1,2-dibromoethane
LCMRL, jig/L
0.064
0.11
0.062
0.092
0.086
0.072
0.099
0.24
0.092
0.057
0.12
0.13
0.25
0.098
0.24
0.035
0.13
0.059
0.064
0.044
0.12
0.18
0.054
0.098
0.35
0.076
0.25
0.041
0.030
0.042
0.051
0.091
0.076
0.096
0.065
0.073
0.064
0.053
0.081
0.058
0.053
0.14
0.14
0.10
0.059
DL Fortification, jig/L
0.025
0.025
0.050
0.050
0.025
0.050
0.050
0.050
0.10
0.10
0.10
0.050
0.25
0.050
0.050
0.025
0.10
0.050
0.050
0.025
0.050
0.050
0.050
0.050
0.50
0.050
0.10
0.025
0.025
0.025
0.050
0.050
0.050
0.050
0.050
0.050
0.050
0.050
0.10
0.050
0.050
0.050
0.050
0.050
0.025
DL,jig/L
0.016
0.022
0.034
0.029
0.013
0.037
0.030
0.039
0.049
0.031
0.050
0.035
0.14
0.050
0.030
0.020
0.046
0.014
0.020
0.010
0.042
0.033
0.025
0.044
0.14
0.026
0.082
0.020
0.017
0.017
0.025
0.035
0.016
0.045
0.018
0.014
0.026
0.024
0.036
0.032
0.030
0.048
0.027
0.030
0.018
524.3-38
-------
Analyte
chlorobenzene
ethylbenzene
1,1,1 ,2-tetrachloroethane
m- and p-xylene
o-xylene
styrene
bromoform
isopropylbenzene
bromobenzene
n-propylbenzene
1, 1,2,2-tetrachloroethane
2-chlorotoluene
1 , 3 ,5 -trimethy Ibenzene
1,2,3-trichloropropane
4-chlorotoluene
t-buty Ibenzene
pentachloroethane
1,2,4-trimethy Ibenzene
sec -buty Ibenzene
4-isopropyltoluene
1 , 3 -dichlorobenzene
1,4-dichlorobenzene
n-buty Ibenzene
hexachloroethane
1,2-dichlorobenzene
l,2-dibromo-3-chloropropane
hexachlorobutadiene
1,2,4-trichlorobenzene
naphthalene
1,2,3-trichlorobenzene
LCMRL, fig/L
0.15
0.085
0.062
0.069
0.039
0.11
0.15
0.059
0.049
0.070
0.093
0.20
0.076
0.16
0.043
0.077
0.13
0.040
0.068
0.052
0.16
0.065
0.16
0.24
0.066
0.27
0.19
0.053
0.090
0.088
DL Fortification, jig/L
0.025
0.025
0.050
0.025
0.025
0.025
0.10
0.025
0.025
0.025
0.050
0.025
0.025
0.10
0.025
0.025
0.050
0.025
0.025
0.025
0.025
0.025
0.10
0.10
0.025
0.10
0.10
0.025
0.025
0.050
DL,u£/L
0.019
0.010
0.029
0.020
0.010
0.011
0.040
0.011
0.020
0.0077
0.013
0.023
0.015
0.050
0.014
0.020
0.043
0.015
0.012
0.012
0.012
0.015
0.045
0.069
0.019
0.063
0.062
0.013
0.012
0.020
524.3-39
-------
TABLE 7. PRECISION AND ACCURACY OF METHOD ANALYTES FORTIFIED AT 0.50,
1.0 AND 10 jig/L IN REAGENT WATER FOR FULL SCAN MODE
Analyte
dichlorodifluoromethane
chlorodifluoromethane
chloromethane
vinyl chloride
1,3 -butadiene
bromomethane
trichlorofluoromethane
diethyl ether
1,1-dichloroethene
carbon disulfide
methyl iodide
allyl chloride
methylene chloride
trans- 1 ,2-dichloroethene
methyl acetate
methyl-t-butyl ether
(MtBE)
t-butyl alcohol (TEA)
diisopropyl ether (DIPE)
1,1-dichloroethane
t-butyl ethyl ether (ETBE)
cis- 1 ,2-dichloroethene
bromochloromethane
chloroform
carbon tetrachloride
tetrahydrofuran
1,1,1 -trichloroethane
1 , 1 -dichloropropene
1-chlorobutane
benzene
t-amyl methyl ether
(TAME)
1 ,2-dichloroethane
trichloroethene
t-amyl ethyl ether (TAEE)
dibromomethane
1 ,2-dichloropropane
bromodichloromethane
cis- 1 , 3 -dichloropropene
toluene
tetrachloroethene
trans- 1 ,3 -dichloropropene
ethyl methacrylate
1 , 1 ,2-trichloroethane
dibromochloromethane
1 ,3 -dichloropropane
1 ,2-dibromoethane
chlorobenzene
Fortified Cone. = 0.50 jig/L
(n=7)
Mean % Recovery
115
109
111
108
113
99.5
94.3
104
99.6
99.4
106
92.8
113
94.9
108
102
103
96.8
98.6
91.7
97.7
102
95.3
89.0
79.5
94.7
87.4
95.8
100
93.6
103
98.8
90.7
99.6
101
96.3
93.0
92.7
90.3
87.5
103
102
89.5
99.4
101
96.8
RSDa
5.6
3.8
3.1
6.1
5.9
9.6
9.4
8.4
8.7
3.8
4.3
6.9
4.3
4.7
2.8
2.0
8.1
1.7
3.6
2.3
3.7
5.1
4.2
2.5
18
5.5
6.9
5.9
2.7
3.2
1.8
6.5
2.9
2.4
4.3
3.5
3.0
4.0
5.8
2.3
3.9
3.1
2.7
3.6
4.0
3.1
Fortified Cone. = 1.0 jig/L
(n=7)
Mean % Recovery
91.7
101
99.0
94.9
98.8
101
95.3
102
94.8
96.4
94.0
95.7
106
100
102
101
97.7
98.0
98.3
97.0
99.5
98.2
99.4
93.9
97.1
98.0
94.9
100
99.4
98.2
101
99.6
95.0
99.9
99.6
97.1
96.0
99.2
98.8
95.2
102
101
95.0
101
101
99.2
RSD
8.5
9.2
6.7
8.1
8.0
10
10
8.0
9.0
8.9
7.5
9.8
5.6
6.8
20
6.4
4.3
2.4
7.2
2.0
8.9
9.3
5.3
7.6
7.4
10
8.0
7.3
7.8
1.9
7.4
7.9
2.5
6.9
8.9
8.7
6.4
9.6
8.8
8.4
7.2
7.3
7.9
9.5
7.9
7.2
Fortified Cone. = 10 jig/L
(n=7)
Mean % Recovery
106
103
101
110
115
103
117
109
97.2
98.5
104
93.4
96.3
96.2
93.4
91.3
82.9
97.9
96.2
92.9
93.8
91.9
98.0
92.3
90.4
98.2
97.1
97.9
96.5
93.1
98.6
94.8
91.8
92.6
93.3
92.8
90.0
95.2
99.7
90.0
94.4
92.0
86.1
94.8
90.8
94.2
RSD
6.2
7.7
6.7
7.7
7.6
7.8
7.0
6.4
6.8
6.6
6.3
5.8
6.2
6.7
3.5
4.9
2.2
1.1
6.3
0.68
6.1
6.0
6.1
5.3
4.3
6.2
5.7
5.9
6.3
0.42
5.9
5.7
1.0
5.8
5.9
6.4
5.8
4.8
3.1
5.5
5.0
4.9
5.6
4.9
5.1
4.2
524.3-40
-------
Analyte
ethylbenzene
1,1, 1 ,2-tetrachloroethane
m- and p-xylene
o-xylene
styrene
bromoform
isopropylbenzene
bromobenzene
n-propylbenzene
1 , 1 ,2,2-tetrachloroethane
2-chlorotoluene
1 ,3 ,5-trimethylbenzene
1 ,2,3 -trichloropropane
4-chlorotoluene
t-butylbenzene
pentachloroethane
1 ,2,4-trimethylbenzene
sec-butylbenzene
4-isopropyltoluene
1 ,3 -dichlorobenzene
1 ,4-dichlorobenzene
n-butylbenzene
hexachloroethane
1 ,2-dichlorobenzene
l,2-dibromo-3-
chloropropane
hexachlorobutadiene
1 ,2,4-trichlorobenzene
naphthalene
1 ,2,3 -trichlorobenzene
Fortified Cone. = 0.50 jig/L
(n=7)
Mean % Recovery
86.9
90.8
89.0
92.1
91.6
86.1
78.9
97.2
78.8
100
79.7
75.8
88.1
92.1
65.5
78.5
84.3
59.4
61.4
86.2
91.8
65.6
86.7
94.0
106
44.8
85.0
59.5
87.5
RSDa
3.9
3.8
4.1
3.6
3.9
4.9
4.0
3.3
5.1
2.6
3.2
3.5
5.5
3.4
8.8
3.3
5.2
7.9
6.9
4.6
3.4
13.6
10
1.4
12
20
3.9
4.5
4.3
Fortified Cone. = 1.0 jig/L
(n=7)
Mean % Recovery
95.9
95.6
98.2
98.3
95.5
92.0
97.1
96.8
94.4
99.2
92.0
93.1
96.1
97.2
91.7
84.6
94.7
90.3
91.3
93.9
95.8
80.7
107
96.3
99.3
94.6
95.6
75.2
96.6
RSD
9.2
8.6
9.2
8.3
8.8
8.1
7.3
9.1
9.9
6.7
8.5
9.0
9.9
7.6
8.6
8.4
8.1
10
11
6.2
7.5
11
8.6
8.3
8.2
12
7.2
7.5
6.6
Fortified Cone. = 10 jig/L
(n=7)
Mean % Recovery
98.3
90.0
96.9
94.4
92.9
80.8
103
90.9
104
87.9
95.4
101
89.6
96.5
105
77.5
99.3
112
108
93.3
92.4
69.7
116
92.0
80.4
122
97.1
86.9
95.9
RSD
2.7
4.5
2.7
3.2
3.9
4.5
3.5
3.8
3.4
4.8
2.3
3.3
4.7
2.4
3.7
6.3
3.2
5.3
5.1
2.4
2.6
2.3
4.1
2.6
3.4
11
4.6
4.0
4.6
RSD = relative standard deviation.
524.3-41
-------
TABLE 8. PRECISION AND ACCURACY OF METHOD ANALYTES FORTIFIED AT 0.50,
1.0 AND 10 jig/L IN DRINKING WATER FROM A GROUND WATER SOURCE3 FOR FULL
SCAN MODE
Analyte
dichlorodifluoromethane
chlorodifluoromethane
chloromethane
vinyl chloride
1,3 -butadiene
bromomethane
trichlorofluoromethane
diethyl ether
1,1-dichloroethene
carbon disulfide
methyl iodide
allyl chloride
methylene chloride
trans- 1 ,2-dichloroethene
methyl acetate
methyl-t-butyl ether
(MtBE)
t-butyl alcohol (TEA)
diisopropyl ether (DIPE)
1,1-dichloroethane
t-butyl ethyl ether (ETBE)
cis- 1 ,2-dichloroethene
bromochloromethane
chloroform
carbon tetrachloride
tetrahydrofuran
1,1,1 -trichloroethane
1 , 1 -dichloropropene
1-chlorobutane
benzene
t-amyl methyl ether
(TAME)
1 ,2-dichloroethane
trichloroethene
t-amyl ethyl ether (TAEE)
dibromomethane
1 ,2-dichloropropane
bromodichloromethane
cis- 1 , 3 -dichloropropene
toluene
tetrachloroethene
trans- 1 ,3 -dichloropropene
ethyl methacrylate
1 , 1 ,2-trichloroethane
dibromochloromethane
1 ,3 -dichloropropane
1 ,2-dibromoethane
Native
Cone., ng/L
(n=3)
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
10
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
9.3
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
6.3
N.D.
N.D.
Fortified Cone. = 0.50
fig/L (n=7)
Mean %
Recovery1"
96.5
103
97.4
103
87.2
103
101
98.2
95.2
95.0
102
91.3
103
87.3
89.4
96.2
79.6
94.4
97.2
92.9
94.4
91.4
d
99.8
97.9
97.9
85.7
89.0
94.1
101
95.4
91.6
94.2
97.9
97.6
d
100.0
101
81.0
94.1
99.2
78.0
d
90.9
99.5
RSDC
6.8
6.3
6.8
5.5
8.5
5.8
6.1
8.1
4.3
4.9
5.2
4.8
7.5
7.7
8.5
4.9
21
2.2
8.7
3.6
6.1
4.7
2.4
3.8
8.0
4.0
6.8
3.0
5.4
28
4.6
6.4
3.4
5.2
5.3
1.2
3.2
2.7
3.0
3.0
2.1
7.0
2.4
8.0
4.5
Fortified Cone. = 1.0
fig/L (n=7)
Mean %
Recovery1"
98.6
99.9
98.4
100
96.3
107
98.5
99.7
96.9
95.7
99.0
89.5
102
91.2
92.0
96.6
90.2
96.3
96.0
94.2
95.2
96.8
d
95.8
90.9
95.3
92.1
92.2
97.1
92.1
98.7
92.0
93.8
96.8
98.5
d
97.0
99.8
83.0
93.4
91.7
89.7
d
95.1
96.6
RSD
2.8
5.5
3.5
3.1
5.2
5.6
3.2
5.0
5.7
3.8
5.2
4.3
3.3
4.0
7.0
1.3
9.6
2.8
3.6
2.6
2.7
4.5
1.7
3.4
8.9
3.7
5.2
3.9
2.2
2.3
2.5
2.7
4.0
2.1
2.1
2.0
2.6
1.7
4.9
3.0
2.0
2.9
2.3
3.0
2.3
Fortified Cone. = 10
fig/L (n=7)
Mean %
Recovery1"
103
103
105
115
118
109
116
114
98.2
101
103
99.0
102
101
98.3
97.9
85.1
98.9
103
96.8
100
98.5
96.3
95.0
92.3
99.5
99.6
103
102
96.5
104
98.5
96.8
99.8
102
102
100
98.7
91.1
95.5
96.1
97.1
96.5
99.6
95.6
RSD
7.6
4.3
5.9
6.5
6.8
8.9
7.0
3.7
6.0
6.7
3.9
6.3
5.9
6.1
3.0
4.7
3.3
2.7
6.0
1.9
5.4
5.3
3.8
5.1
7.3
5.8
6.1
5.8
5.7
2.0
4.5
6.0
3.2
5.1
5.4
2.7
5.1
6.0
5.7
5.2
5.2
5.2
2.8
5.1
4.4
524.3-42
-------
Analyte
chlorobenzene
ethylbenzene
1,1, 1 ,2-tetrachloroethane
m- and p-xylene
o-xylene
styrene
bromoform
isopropylbenzene
bromobenzene
n-propylbenzene
1 , 1 ,2,2-tetrachloroethane
2-chlorotoluene
1 ,3 ,5-trimethylbenzene
1 ,2,3 -trichloropropane
4-chlorotoluene
t-butylbenzene
pentachloroethane
1 ,2,4-trimethylbenzene
sec-butylbenzene
4-isopropyltoluene
1 ,3 -dichlorobenzene
1 ,4-dichlorobenzene
n-butylbenzene
hexachloroethane
1 ,2-dichlorobenzene
l,2-dibromo-3-
chloropropane
hexachlorobutadiene
1 ,2,4-trichlorobenzene
naphthalene
1 ,2,3 -trichlorobenzene
Native
Cone., ng/L
(n=3)
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
1.1
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
Fortified Cone. = 0.50
fig/L (n=7)
Mean %
Recovery1"
95.3
97.0
98.5
97.4
97.0
99.3
d
94.0
98.1
95.7
97.4
95.5
96.0
90.4
97.8
90.3
123
101
95.6
98.5
93.1
91.5
98.0
91.0
92.6
108
96.5
99.3
98.9
88.8
RSDC
4.1
5.1
4.1
4.8
6.2
4.9
4.4
4.1
3.2
4.8
5.7
2.1
5.1
10
4.0
6.2
13
3.7
5.1
3.5
4.5
6.0
2.9
5.7
4.6
11
5.8
4.0
3.3
6.0
Fortified Cone. = 1.0
fig/L (n=7)
Mean %
Recovery1"
98.2
96.0
95.8
95.7
95.2
94.9
78.1
95.0
95.6
96.0
102
96.3
94.7
96.0
96.2
97.1
133
98.2
96.4
96.3
96.5
96.7
94.6
104
97.1
96.0
94.5
94.6
88.7
91.3
RSD
1.9
3.2
2.6
3.3
2.2
3.4
3.5
3.6
3.6
2.8
1.7
2.3
3.0
4.5
3.6
4.1
5.0
2.3
3.6
3.0
4.0
2.2
5.3
4.8
2.7
2.6
6.1
3.7
3.0
3.3
Fortified Cone. = 10
fig/L (n=7)
Mean %
Recovery1"
98.0
100
95.5
98.7
98.5
97.6
87.7
98.9
99.9
103
99.0
102
103
94.8
103
103
100
103
101
100
99.6
99.7
99.1
106
99.7
89.1
90.1
96.0
94.1
95.7
RSD
5.4
6.0
4.6
6.1
6.3
5.5
3.7
6.2
5.3
6.0
4.5
5.8
5.7
4.9
5.3
6.2
4.8
5.3
6.6
6.7
5.8
5.1
7.1
7.7
4.9
2.9
8.3
4.9
4.2
4.5
Ground water physical parameters: pH = 7.45; hardness = 308 milligrams/liter (mg/L) (as CaCO3); free chlorine =
0.94 mg/L.
Recoveries corrected for native levels in the unfortified matrix.
RSD = relative standard deviation.
Fortified at less than !/2 the concentration in the native matrix.
524.3-43
-------
TABLE 9. PRECISION AND ACCURACY OF METHOD ANALYTES FORTIFIED AT 0.50,
1.0 AND 10 jig/L IN DRINKING WATER FROM A SURFACE WATER SOURCE3 FOR FULL
SCAN MODE
Analyte
dichlorodifluoromethane
chlorodifluoromethane
chloromethane
vinyl chloride
1,3 -butadiene
bromomethane
trichlorofluoromethane
diethyl ether
1,1-dichloroethene
carbon disulfide
methyl iodide
allyl chloride
methylene chloride
trans- 1 ,2-dichloroethene
methyl acetate
methyl-t-butyl ether
(MtBE)
t-butyl alcohol (TEA)
diisopropyl ether (DIPE)
1,1-dichloroethane
t-butyl ethyl ether (ETBE)
cis- 1 ,2-dichloroethene
bromochloromethane
chloroform
carbon tetrachloride
tetrahydrofuran
1,1,1 -trichloroethane
1 , 1 -dichloropropene
1-chlorobutane
benzene
t-amyl methyl ether
(TAME)
1 ,2-dichloroethane
trichloroethene
t-amyl ethyl ether (TAEE)
dibromomethane
1 ,2-dichloropropane
bromodichloromethane
cis- 1 , 3 -dichloropropene
toluene
tetrachloroethene
trans- 1 ,3 -dichloropropene
ethyl methacrylate
1 , 1 ,2-trichloroethane
dibromochloromethane
1 ,3 -dichloropropane
1 ,2-dibromoethane
Native
Cone., |ig/L
(n=3)
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
16
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
12
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
9.6
N.D.
N.D.
Fortified Cone. = 0.50
fig/L (n=7)
Mean %
Recovery1"
108
102
104
101
103
97.9
99.7
94.3
104
102
111
107
98.8
95.9
94.5
105
113
94.4
99.1
92.7
98.6
96.7
d
106
108
102
97.4
100
103
92.1
99.9
100
95.1
106
100
d
105
97.0
93.7
102
107
92.3
d
103
98.9
RSDC
4.9
5.7
2.4
7.4
9.0
9.6
7.7
10
5.4
3.5
4.3
3.4
4.8
6.8
14
7.0
11
1.6
4.1
3.1
4.3
3.1
8.3
3.1
18
4.3
6.0
4.7
3.0
1.8
3.7
4.5
2.2
7.1
5.7
6.4
3.0
3.8
3.5
2.6
3.3
7.2
4.8
5.6
6.6
Fortified Cone. = 1.0
fig/L (n=7)
Mean %
Recovery1"
92.4
96.9
99.0
98.1
98.0
102
95.3
97.8
94.8
93.8
96.3
95.8
95.0
94.6
92.7
95.4
90.1
94.7
95.2
95.6
96.4
95.7
d
95.0
95.3
94.8
94.9
93.7
96.7
92.8
95.8
94.0
97.4
99.4
97.6
d
97.5
95.7
88.7
95.6
93.4
94.3
d
99.2
97.0
RSD
3.5
3.6
6.0
3.0
5.3
3.1
6.5
5.5
3.4
2.8
2.2
4.6
4.8
3.8
5.6
2.0
5.5
1.1
2.9
1.6
3.1
5.0
1.9
3.2
6.2
2.6
3.4
3.4
2.0
1.1
3.7
2.4
2.4
3.1
3.9
1.6
3.2
1.7
3.2
2.1
2.8
4.8
1.2
2.9
3.0
Fortified Cone. = 10
fig/L (n=7)
Mean %
Recovery1"
100
104
103
115
120
112
118
119
97.5
99.5
103
99.4
101
99.4
91.4
97.2
84.9
101
103
98.8
100
97.9
80.9
96.5
91.6
98.8
99.0
103
102
98.2
105
98.0
98.3
99.7
103
97.0
100
99.0
94.2
96.3
97.2
98.2
97.7
101
96.8
RSD
3.3
4.1
2.8
3.2
3.4
2.1
2.9
1.9
2.6
3.0
3.4
2.8
2.3
3.1
14
1.4
2.7
2.0
2.5
1.7
3.1
2.0
1.8
3.7
2.7
2.9
2.1
2.9
2.5
1.1
1.3
2.5
2.3
2.0
1.9
1.5
1.9
2.1
1.9
2.4
1.5
1.4
2.6
1.5
2.2
524.3-44
-------
Analyte
chlorobenzene
ethylbenzene
1,1, 1 ,2-tetrachloroethane
m- and p-xylene
o-xylene
styrene
bromoform
isopropylbenzene
bromobenzene
n-propylbenzene
1 , 1 ,2,2-tetrachloroethane
2-chlorotoluene
1 ,3 ,5-trimethylbenzene
1 ,2,3 -trichloropropane
4-chlorotoluene
t-butylbenzene
pentachloroethane
1 ,2,4-trimethylbenzene
sec-butylbenzene
4-isopropyltoluene
1 ,3 -dichlorobenzene
1 ,4-dichlorobenzene
n-butylbenzene
hexachloroethane
1 ,2-dichlorobenzene
l,2-dibromo-3-
chloropropane
hexachlorobutadiene
1 ,2,4-trichlorobenzene
naphthalene
1 ,2,3 -trichlorobenzene
Native
Cone., |4.g/L
(n=3)
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
1.7
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
N.D.
Fortified Cone. = 0.50
fig/L (n=7)
Mean %
Recovery1"
96.3
99.9
110
94.1
96.7
105
d
98.2
99.4
97.0
106
99.1
98.2
123
97.9
99.4
117
97.2
96.7
90.2
96.8
92.0
87.1
91.7
95.6
113
96.4
99.1
117
103
RSDC
2.5
3.8
4.1
2.5
3.0
2.9
7.5
2.7
2.6
3.8
5.3
5.2
3.0
6.0
3.7
5.8
7.6
4.1
2.7
4.1
4.3
2.6
6.5
6.0
3.2
7.3
3.9
4.6
6.0
5.0
Fortified Cone. = 1.0
fig/L (n=7)
Mean %
Recovery1"
97.2
96.5
99.6
94.0
94.9
97.0
92.6
95.7
95.7
94.2
98.4
95.9
94.8
100
96.2
99.8
118
95.1
94.9
91.4
97.0
94.3
89.3
97.4
95.9
90.8
91.5
93.6
94.2
94.5
RSD
2.1
2.4
4.0
2.5
3.3
2.3
3.7
3.4
5.2
2.9
2.3
4.3
2.9
4.1
5.1
5.6
7.0
3.7
4.0
4.1
2.8
3.8
5.2
8.1
3.3
6.1
4.7
4.8
4.4
4.8
Fortified Cone. = 10
fig/L (n=7)
Mean %
Recovery1"
99.1
102
97.0
100
100
98.8
90.8
102
99.1
105
96.9
103
104
94.1
104
104
97.3
104
105
103
99.9
99.2
101
108
99.4
86.5
96.4
96.8
93.8
96.3
RSD
2.0
2.4
1.8
2.2
1.8
1.7
2.2
2.2
1.3
1.2
1.4
0.86
0.66
2.0
0.75
0.73
2.9
0.50
1.4
1.1
0.65
1.3
1.9
2.2
1.1
2.4
1.2
1.1
1.2
0.75
Surface water physical parameters: pH = 7.43; hardness = 154 milligrams/liter (mg/L) (as CaCO3); free chlorine =
2.7 mg/L; total chlorine = 3.7 mg/L.
Recoveries corrected for native levels in the unfortified matrix.
RSD = relative standard deviation.
Fortified at less than 1A the concentration in the native matrix.
524.3-45
-------
TABLE 10. LOWEST CONCENTRATION MINIMUM REPORTING LEVELS (LCMRLs)
AND DETECTION LIMITS (DLs) FOR SIM MODE
Analyte
1 ,2-dibromoethane
1 ,2-dibromo-3 -chloropropane
DL Fortification, ng/L
0.0020
0.0020
LCMRL, jig/L
0.0041
0.0017
DL, ng/L
0.0010
0.0016
TABLE 11. PRECISION AND ACCURACY OF METHOD ANALYTES FORTIFIED AT 0.010,
0.020 AND 0.10 jig/L IN REAGENT WATER FOR SIM MODE
Analyte
1 ,2-dibromoethane
l,2-dibromo-3-
chloropropane
Fortified Cone. =
0.010 jig/L (n=7)
Mean % Recovery
84.5
65.4
RSDa
5.8
14
Fortified Cone. =
0.020 jig/L (n=7)
Mean % Recovery
91.1
89.9
RSD
3.2
12
Fortified Cone. =
0.10 jig/L (n=7)
Mean % Recovery
87.9
77.4
RSD
2.2
3.6
RSD = relative percent deviation.
TABLE 12. PRECISION AND ACCURACY OF METHOD ANALYTES FORTIFIED AT 0.010,
0.020 AND 0.10 jig/L IN DRINKING WATER FROM A GROUND WATER SOURCE3 FOR
SIM MODE
Analyte
1 ,2-dibromoethane
1 ,2-dibromo-3 -chloropropane
Native
Cone.,
Hg/L
(n=3)
0.0001
N.D.
Fortified Cone. =
0.010 jig/L (n=7)
Mean %
Recovery
85.1
99.4
RSDb
4.9
9.6
Fortified Cone. =
0.020 jig/L (n=7)
Mean %
Recovery
91.7
107
RSD
4.0
12.7
Fortified Cone. =
0.10 fig/L (n=7)
Mean %
Recovery
92.6
96.8
RSD
2.9
4.5
Recoveries corrected for native levels in the unfortified matrix.
RSD = relative percent deviation.
TABLE 13. PRECISION AND ACCURACY OF METHOD ANALYTES FORTIFIED AT 0.010,
0.020 AND 0.10 jig/L IN DRINKING WATER FROM A SURFACE WATER SOURCE3 FOR
SIM MODE
Analyte
1 ,2-dibromoethane
l,2-dibromo-3-
chloropropane
Native
Cone., (ig/L
(n=3)
0.0001
0.0009
Fortified Cone. =
0.010 jig/L (n=7)
Mean %
Recovery
106
87.5
RSDb
6.2
14
Fortified Cone. =
0.020 jig/L (n=7)
Mean %
Recovery
88.1
72.1
RSD
2.5
6.3
Fortified Cone. =
0.10 fig/L (n=7)
Mean %
Recovery
90.0
85.6
RSD
3.0
3.0
Recoveries corrected for native levels in the unfortified matrix.
524.3-46
-------
TABLE 14. SAMPLE HOLDING TIME DATA FOR METHOD ANALYTES FORTIFIED AT
20 jig/L IN A CHLORINATED SURFACE WATER3 (n=3 SAMPLES)
Analyte
dichlorodifluoromethane
chlorodifluoromethane
chloromethane
vinyl chloride
1,3 -butadiene
bromomethane
trichlorofluoromethane
diethyl ether
1,1-dichloroethene
carbon disulfide
methyl iodide
allyl chloride
methylene chloride
trans- 1 ,2-dichloroethene
methyl acetate
methyl-t-butyl ether (MtBE)
t-butyl alcohol (TEA)
diisopropyl ether (DIPE)
1,1-dichloroethane
t-butyl ethyl ether (ETBE)
cis- 1 ,2-dichloroethene
bromochloromethane
chloroform
carbon tetrachloride
tetrahydrofuran
1,1,1 -trichloroethane
1 , 1 -dichloropropene
1-chlorobutane
benzene
t-amyl methyl ether (TAME)
1 ,2-dichloroethane
trichloroethene
t-amyl ethyl ether (TAEE)
dibromomethane
1 ,2-dichloropropane
bromodichloromethane
cis- 1 , 3 -dichloropropene
toluene
tetrachloroethene
trans- 1 ,3 -dichloropropene
ethyl methacrylate
1 , 1 ,2-trichloroethane
dibromochloromethane
1 ,3 -dichloropropane
1 ,2-dibromoethane
chlorobenzene
ethylbenzene
1,1,1 ,2-tetrachloroethane
DayO
Mean %
Recovery
110
112
114
117
116
117
114
110
106
108
106
108
106
107
105
104
105
107
109
105
106
104
102
108
102
109
110
114
108
105
108
105
107
106
108
105
106
109
110
106
108
105
104
108
104
108
115
106
RSDb
2.2
2.0
0.88
0.99
1.3
6.9
0.54
1.2
0.94
0.58
1.3
0.57
0.17
0.89
3.4
0.92
3.2
0.71
1.0
0.30
0.66
0.64
0.56
1.4
1.4
0.70
0.24
0.25
0.63
0.56
2.1
0.28
0.31
1.5
0.48
0.85
0.33
1.3
2.4
1.9
1.4
1.8
0.99
1.0
1.7
1.4
1.1
1.6
Day 7
Mean %
Recovery
107
109
110
113
106
116
116
106
107
106
106
100
106
103
101
101
104
109
108
107
105
104
100
109
98.4
109
107
111
106
107
105
105
108
105
106
104
98.5
108
106
99.1
104
103
104
104
104
106
110
106
RSD
2.5
0.63
1.1
1.6
1.9
3.5
2.9
1.5
0.62
1.9
0.33
0.73
0.55
1.8
0.32
0.049
2.9
0.72
0.82
0.53
0.67
1.4
0.91
1.2
1.5
0.89
1.5
1.1
1.2
0.45
0.59
0.85
0.73
0.42
0.21
1.2
1.0
0.46
1.1
0.94
0.56
0.93
0.98
0.10
1.3
0.36
0.33
0.35
Day 14
Mean %
Recovery
111
107
112
116
105
114
117
113
111
107
101
101
108
107
83.2
105
105
109
111
107
108
105
107
116
101
115
108
115
109
107
108
107
107
107
109
109
96.7
110
111
96.4
105
106
107
106
106
109
116
110
RSD
3.9
0.87
2.0
0.87
4.6
2.5
2.4
1.0
2.3
3.0
0.93
1.0
0.92
1.5
4.0
0.79
1.8
0.65
0.74
0.89
0.71
0.45
0.97
2.2
1.7
0.94
1.5
0.90
0.57
0.59
1.2
0.16
0.69
0.33
0.78
1.2
1.2
1.2
2.7
0.30
1.5
2.1
0.98
1.2
0.72
1.1
1.4
0.92
524.3-47
-------
Analyte
m- and p-xylene
o-xylene
styrene
bromoform
isopropylbenzene
bromobenzene
n-propylbenzene
1 , 1 ,2,2-tetrachloroethane
2-chlorotoluene
1 ,3 ,5-trimethylbenzene
1,2,3 -trichloropropane
4-chlorotoluene
t-butylbenzene
pentachloroethane
1 ,2,4-trimethylbenzene
sec-butylbenzene
4-isopropyltoluene
1 ,3 -dichlorobenzene
1 ,4-dichlorobenzene
n-butylbenzene
hexachloroethane
1 ,2-dichlorobenzene
l,2-dibromo-3-
chloropropane
hexachlorobutadiene
1 ,2,4-trichlorobenzene
naphthalene
1 ,2,3 -trichlorobenzene
DayO
Mean %
Recovery
114
113
111
103
118
109
122
108
115
121
106
113
123
109
120
125
123
113
113
122
123
111
105
122
114
112
114
RSDb
1.3
0.83
1.3
1.8
1.2
0.38
1.3
0.63
0.65
1.2
1.6
4.1
0.84
2.2
0.99
1.5
1.3
0.85
1.1
1.3
0.42
0.82
1.9
2.5
1.3
0.77
0.53
Day 7
Mean %
Recovery
110
109
106
101
114
104
111
100
107
111
102
106
115
103
110
115
112
105
104
106
115
104
99.1
112
102
103
103
RSD
0.70
0.87
0.62
1.7
0.81
1.9
2.0
.5
.9
.4
2.5
.8
.3
3.0
2.0
1.8
2.4
1.7
2.0
3.6
0.82
1.7
1.9
3.6
2.3
1.0
1.7
Day 14
Mean %
Recovery
114
115
108
108
123
107
119
103
112
120
102
110
129
112
118
129
123
109
107
111
132
108
103
124
105
107
108
RSD
2.3
0.79
1.7
1.5
1.5
1.8
2.1
0.83
2.1
1.7
1.4
2.0
0.38
0.47
1.5
1.9
2.6
1.5
1.7
6.5
1.6
1.0
2.4
2.1
3.0
2.1
2.0
Surface water physical parameters: pH = 7.43; hardness = 154 milligrams/liter (mg/L) (as CaCO3); free chlorine =
2.7 mg/L; total chlorine = 3.7 mg/L.
RSD = relative percent deviation.
524.3-48
-------
TABLE 15. INITIAL DEMONSTRATION OF CAPABILITY (IDC) QUALITY CONTROL
REQUIREMENTS
Method
Reference
Section
9.2.1
Section
9.2.1
Section
9.2.2
Section
9.2.3
Section
9.2.4
Section
9.2.5
Requirement
Demonstration of
low system
background
Test for system
carryover
Demonstration of
precision
Demonstration of
accuracy
MRL confirmation
Quality Control
Sample (QCS)
Specification and Frequency
Analyze a Laboratory Reagent Blank
(LRB) prior to any other IDC steps.
Analyze an LRB after the high
calibration standard during the IDC
calibration.
Analyze 7 replicate Laboratory Fortified
Blanks (LFBs) fortified near the
midrange concentration.
Calculate average recovery for replicates
used in Section 9.2.2.
Fortify and analyze 7 replicate LFBs at
the proposed MRL concentration.
Confirm that the Upper Prediction
Interval of Results (PIR) and Lower PIR
(Sect. 9.2.4.2) meet the recovery criteria.
Analyze mid-level QCS.
Acceptance Criteria
Demonstrate that all method analytes are
50%
Results must be within +30% of the true
value.
524.3-49
-------
TABLE 16. ONGOING QUALITY CONTROL REQUIREMENTS
Method
Reference
Requirement
Specification and Frequency
Acceptance Criteria
Section
10.1
Initial calibration
Use the internal standard calibration
technique to generate a linear or
quadratic calibration curve. Use at
least 7 standard concentrations.
Validate the calibration curve as
described in Section 10.1.10.
When each calibration standard is
calculated as an unknown using the
calibration curve, the lowest level
standard must be within +50% of the
true value. All other points must be
within +30% of the true value.
Section
9.3.1
Laboratory Reagent
Blank (LRB)
Analyze one LRB with each Analysis
Batch.
Demonstrate that all method analytes
are below 1A the Minimum Reporting
Level (MRL), and that possible
interference from reagents and
glassware do not prevent identification
and quantitation of method analytes.
Section
10.2
Continuing Calibra-
tion Check (CCC)
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.
The lowest level CCC must be within
+50% of the true value. All other
points must be within +30% of the
true value.
Results for field samples that are not
bracketed by acceptable CCCs are
invalid.
Section
9.3.5
Internal standard (IS)
Internal standards are added to all
standards and samples.
Peak area counts for each IS must be
within +30% of the area in the most
recent CCC, and +50% of the average
peak area in the initial calibration.
Section
9.3.6
Surrogate analytes
Surrogates are added to all field
samples and QC samples prior to
analysis.
70% to 130% recovery
Section
9.3.7
Laboratory Fortified
Sample Matrix
(LFSM)
Analyze one LFSM per Analysis
Batch. Fortify the LFSM with
method analytes at a concentration
close to but greater than the native
concentrations (if known).
For analytes fortified at concentrations
<2 x the MRL, the result must be
within +50% of the true value. All
other analytes must be within +30% of
the true value.
Section
9.3.8
Laboratory Fortified
Sample Matrix Dup-
licate (LFSMD) or
Field Duplicate (FD)
Analyze at least one LFSMD or FD
with each Analysis Batch.
For LFSMDs or FDs, relative percent
differences must be <30% (<50% if
concentration <2 x the MRL.).
Section
9.3.9
Field Reagent Blank
(FRB)
Analyze FRB if method analytes are
detected in field samples (except
disinfection byproducts).
Qualify results of any analyte detected
in both field samples and the FRB.
Section
9.3.10
Quality Control
Sample (QCS)
Analyze mid-level QCS at least
quarterly.
Results must be +30% of the true
value.
524.3-50
-------
Abundance
240000 H
220000 -
"
200000 •
1 80000 '-
1 60000 -
1 40000 '-
1 20000 •
1 00000 -
80000 '-
60000 -
40000 '-
20000 :
n .
1
/
v\
\x-
V
Time--* 1.60
1.70
1.80
i
1.90
2.00
2.10
2.20
2.30
Figure 1. Mass chromatograms of "gases." @ 40 jig/L.
524.3-51
-------
Abundance
900000 -
800000 •
700000 -
600000 -
500000 -
400000 -
300000 •
200000 -
100000 -
Time-->
4,5
1 ' \^
2.00
16
19
2.50
3.00
3.50
4.00
4.50
21
5.00
Figure 2a. Reconstructed total ion chromatogram: 40-p,g/L procedural calibration standard. See Table 4 for peak number to peak
name cross reference.
524.3-52
-------
Abundance
1800000
400000 -
200000 -
Time-->
6.00
7.00
6.00
43,44
10.00
Figure 2b. Reconstructed total ion chromatogram: 40-p.g/L procedural calibration standard. See Table 4 for peak number to peak
name cross reference.
524.3-53
-------
Abundance
3500000 -
3000000 -
2500000 -
2000000 -
1500000-
1000000-
500000 -
52,53
74
62,63,64
59,60
/48,49,50
69
70
71
72
\
73
75,76,77
78
81
80
791
82
Time-->
11.00
12.00
13.00
14.00
\ \ \ r
Figure 2c. Reconstructed total ion chromatogram: 40-p,g/L procedural calibration standard. See Table 4 for peak number to peak
name cross reference.
524.3-54
-------
Abundance
1600000
1400000
1200000
1000000
800000
600000 -
400000 -
200000 -
0
Time~>
5.00
10.00
15.00
Figure 3. Reconstructed total ion chromatogram: method analytes fortified into drinking water @ 20
524.3-55
------- |