4>EPA
United States
Environmental Protection
Agency
Method 523: Determination of Triazine Pesticides and their
Degradates in Drinking Water by Gas Chromatography/Mass
Spectrometry (GC/MS)
Office of Water (MLK 140) EPA Document No. 815-R-l 1-002 February 2011 http://www.epa.gov/safewater/
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METHOD 523 DETERMINATION OF TRIAZINE PESTICIDES AND THEIR
DEGRADATES IN DRINKING WATER BY GAS
CHROMATOGRAPHY/MASS SPECTROMETRY (GC/MS)
Version 1.0
February 2011
M. M. Domino (Sullivan International Group, Inc.)
B. V. Pepich (U.S. EPA, Region 10 Laboratory)
D. J. Munch (U.S. EPA, Office of Ground Water and Drinking Water)
TECHNICAL SUPPORT CENTER
STANDARDS AND RISK MANAGEMENT DIVISION
OFFICE OF GROUND WATER AND DRINKING WATER
U. S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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METHOD 523
DETERMINATION OF TRIAZINE PESTICIDES AND THEIR DEGRADATES IN
DRINKING WATER BY GAS CHROMATOGRAPHY/MASS SPECTROMETRY (GC/MS)
1. SCOPE AND APPLICATION
1.1 This is a gas chromatography/mass spectrometry (GC/MS) method for the determination of
triazine pesticides and their degradation products in finished drinking waters. 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:
Chemical Abstract Services
Analvte Registry Number (CASRN)
Atrazine 1912-24-9
Atrazine-desethyl 6190-65-4
Atrazine-desethyl-desisopropyl 3397-62-4
Atrazine-desisopropyl 1007-28-9
Cyanazine 21725-46-2
Propazine 139-40-2
Simazine 122-34-9
Terbuthylazine-desethyl 30125-63-4
Terbuthylazine 5915-41-3
Prometon 1610-18-0
Prometryn 7287-19-6
Ametryn 834-12-8
Simetryn 1014-70-6
1.2 The MS conditions described in this method were developed using a time-of-flight (TOF)
GC/MS system. The method was validated at a second laboratory that used a quadrupole-
based GC/MS system.
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 0.40 to 2.1 micrograms per liter (ng/L), and are listed in
Table 4 (all Tables are found in Section 17). The procedure used to determine the LCMRL is
described elsewhere.1
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1.4 Laboratories using this method are not required to determine an LCMRL, 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.
Determining the DL for analytes in this method is optional (Sect. 9.2.6). DLs for method
analytes fortified into RW ranged from 0.10 to 0.69 |ig/L. These values are presented in
Table 4.
1.6 This method is intended for use by analysts skilled in solid-phase extractions (SPE), 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 the GC and MS
conditions Changes may not be made to sample collection and preservation (Sect. 8), to
the sample extraction procedure (Sect. 11.3), or to the quality control (QC)
requirements (Sect. 9). Method modifications must be considered only to improve method
performance. Modifications that are introduced in the interest of reducing cost or sample
processing time, but result in poorer method performance, may not be used. 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 10 and 11) are met, and that method performance can be
verified in a real sample matrix (Sect. 9.4).
2. SUMMARY OF METHOD
2.1 Samples are pH adjusted and dechlorinated with ammonium acetate (MLX^HsC^) and pro-
tected from microbial degradation using 2-chloroacetamide during sample collection. Sam-
ples are fortified with isotopically enriched surrogates [Atrazine-desethyl-desisopropyl(13C3),
Atrazine-desisopropyl-t/5(ethyl-J5), Cyanazme-d5(N-ethy\-d5)., and Simazine-Jio(diethyl-Jio)]
just prior to extraction. Analytes are extracted from a 250-milliliter (mL) sample aliquot
using 250-milligram (mg) carbon cartridges. After extraction, the cartridges are dewatered
with a small volume of methanol (MeOH) and then eluted with 2 mL of ethyl acetate
followed by two, 6-mL aliquots of 9:1 (v:v) dichloromethane/methanol (DCM/MeOH). The
extracts are dried using anhydrous sodium sulfate (Na2SC>4) and concentrated using a stream
of nitrogen gas. Isotopically labeled internal standards (IS) [Atrazine-^ethyl-Js) and
Atrazine-desethyl-Jy^sopropyl-Jy)] are added, and the extracts brought to a final 1.0-mL
volume. Extracts are analyzed using a GC/MS operated in full scan mode. Method analytes
are identified by comparing retention times and the acquired mass spectra to retention times
and reference spectra for calibration standards acquired under identical GC/MS conditions.
The concentration of each method analyte is determined using the IS technique.
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3. DEFINITIONS
3.1 ANALYSIS BATCH - A set of samples that is analyzed on the same instrument during a
24-hour period that begins and ends with the analysis of the appropriate Continuing
Calibration Check (CCC) Standards. Additional CCCs may be required depending on the
length of the Analysis Batch and/or the number of field samples.
3.2 CALIBRATION STANDARD (CAL) - A solution of the method analytes prepared from the
primary dilution standard(s) (PDS) and stock standard solution(s), which includes the ISs and
SURs. The CAL solutions are used to calibrate the instrument response with respect to
analyte concentration.
3.3 CONTINUING CALIBRATION CHECK (CCC) - A CAL containing the method analytes,
surrogates, and ISs, which is analyzed periodically to verify the accuracy of the existing
calibration.
3.4 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.
3.5 EXTRACTION BATCH - A set of up to 20 field samples (not including QC samples)
extracted together by the same person(s) during a work day using the same lot of SPE
devices, solvents, surrogate solution, and fortifying solutions. Required QC samples include
Laboratory Reagent Blank, Laboratory Fortified Blank, Laboratory Fortified Matrix, and
either a Field Duplicate or Laboratory Fortified Sample Matrix Duplicate.
3.6 FIELD DUPLICATES (FD1 and FD2) - Separate samples collected at the same time, and
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. 3.9) and Laboratory Fortified Sample Matrix Duplicate (Sect.
3.10) QC samples.
3.7 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.
3.8 LABORATORY FORTIFIED BLANK (LFB) - An aliquot of reagent water to which known
quantities of the method analytes are added. The LFB is extracted and analyzed as a sample
including use of the preservation procedures in Section 8. The LFB is used during the IDC to
verify method performance for precision and accuracy, and as an ongoing QC element.
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3.9 LABORATORY FORTIFIED SAMPLE MATRIX (LFSM) - A Field Duplicate to which
known quantities of the method analytes are added. The LFSM is extracted and analyzed as a
sample, and its purpose is to determine whether the sample matrix contributes bias to the
analytical results.
3.10 LABORATORY FORTIFIED SAMPLE MATRIX DUPLICATE (LFSMD) - A second
Field Duplicate of the same field sample used to prepare the LFSM which is fortified
identically to the LFSM. The LFSMD is used instead of the FD to assess method precision
and accuracy when the occurrence of the method analytes at a concentration greater than the
MRL is infrequent.
3.11 LABORATORY REAGENT BLANK (LRB) - An aliquot of RW that is treated exactly as a
sample including exposure to all glassware, equipment, solvents, reagents, sample
preservatives, ISs, and SURs associated with the Extraction Batch. The LRB is used to
determine if method analytes or other interferences are introduced via the laboratory
environment, the reagents, or the apparatus.
3.12 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 and 150% range is at least 99% l
3.13 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.
3.14 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 CAL for the method analyte. A laboratory may be
required to demonstrate a specific MRL by a regulatory body if this method is being
performed for compliance purposes.
3.15 PRIMARY DILUTION STANDARD (PDS) - A solution containing the method analytes (or
internal standards or surrogate analytes) prepared in the laboratory from Stock Standard
Solutions and diluted as needed to prepare calibration standards and sample fortification
solutions.
3.16 QUALITY CONTROL SAMPLE (QCS) - A solution containing the method analytes at a
known concentration, which 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.
3.17 REAGENT WATER (RW) - Purified water that does not contain any measurable quantity of
the method analytes or interfering compounds at or above 1/3 the MRL.
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3.18 STOCK STANDARD SOLUTION - 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.
3.19 SURROGATE ANALYTE (SUR) - A pure analyte, extremely unlikely to be found in any
sample, that is added to a sample aliquot in a known amount before extraction, and which is
measured with the same procedures used to measure other sample components. The purpose
of the SUR is to monitor method performance with each sample.
4. INTERFERENCES
4.1 All glassware must be meticulously cleaned. Wash glassware with detergent and tap water,
rinse with tap water, followed by RW. Volumetric glassware must be solvent rinsed after
washing and dried in a low temperature oven [<120 degrees Centigrade (°C)] or air-dried.
Non-volumetric glassware may be heated in a muffle furnace at 400 °C for two hours as a
substitute for a solvent rinse.
4.2 Method interferences may be caused by contaminants in solvents, reagents (including RW),
sample bottles and caps, and other sample processing hardware. These interferences may
lead to discrete artifacts and/or elevated baselines in the chromatograms. All laboratory
reagents and equipment must be routinely demonstrated to be free from interferences (less
than 1/3 the MRL for the method analytes) under the conditions of the analysis. This may be
accomplished by analyzing LRBs as described in Section 9.3.1.
4.3 Preservatives (Sect. 8.1) are added to samples to ensure the stability of method analytes
during shipping and storage prior to analysis. The potential exists for trace-level organic
contaminants in these reagents. Interferences from these sources must be evaluated by
analysis of LRBs, particularly when new lots of reagents are acquired.
4.4 SPE cartridges may be a source of interferences. The analysis of LRBs can provide
important information regarding the presence or absence of such interferences. Brands and
lots of SPE devices must be tested to ensure that contamination does not preclude analyte
identification and quantitation.
4.5 Silicone compounds may be leached from punctured septa of autosampler vials. This can
occur after repeated injections from the same autosampler vial. These silicone compounds,
which appear as regularly spaced chromatographic peaks with similar fragmentation patterns,
could unnecessarily complicate the total ion chromatograms and may interfere with the
identification of the method analytes.
4.6 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.
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4.7 This method uses a number of isotopically labeled ISs and SUR analytes. These standards
must be determined to be sufficiently free of the unlabeled parent molecule to permit accurate
quantitation of field samples. This is verified during the IDC via analysis of LRBs.
5. SAFETY
5.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely
defined. Each chemical must 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.3'4 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.5
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 bottles (250 mL or larger) fitted with polytetra-
fluoroethylene (PTFE)-faced silicone septa and polypropylene screw caps (I-Chem Cat.
No. S249-0250 or equivalent).
6.2 VIALS - Amber, 2-mL glass autosampler vials with PTFE-faced septa (Fisher Cat. No. 03-
375-19B or equivalent).
6.3 MICRO SYRINGES - Suggested sizes include 10, 25, 50, 100, 250, and 500 |iL.
6.4 VOLUMETRIC FLASKS - Class A, suggested sizes include 5, 10, 50, 100, 200, and 500
mL for preparation of reagents and standards.
6.5 VOLUMETRIC PIPETTES - Class A, suggested sizes include 2, 3, 4, 6, and 10 mL.
6.6 ANALYTICAL BALANCE - Capable of weighing to the nearest 0.0001 gram.
6.7 SPE VACUUM MANIFOLD AND SAMPLE TRANSFER LINES - Supelco Visi-Prep™
Part No. 57044 or equivalent, and Supelco Visi-Prep™ Part No. 57275 or equivalent.
6.8 SPE CARTRIDGES - Cartridges packed with 250 mg of graphitized, non-porous carbon
(Supelco ENVI-Carb™, Cat. No. 57092 or equivalent).
6.9 AUTOMATED EXTRACTORS - An automated or robotic system designed for use with
SPE cartridges may be used if all quality control requirements discussed in Section 9 are met.
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Automated systems may use either vacuum or positive pressure to process samples and
solvents through the cartridges. All extraction and elution steps must be the same as in the
manual procedure. Extraction and/or elution steps may not be changed or omitted to accom-
modate the use of an automated system.
6.10 DISPOSABLE PASTEUR PIPETTES - Nine-inch borosilicate glass (Fisher Cat. No. 13-
678-20C or equivalent).
6.11 DRYING COLUMN - The drying column must be able to contain 3 g of anhydrous
plus several milliliters of eluate. The drying column must not leach interfering compounds or
irreversibly adsorb method analytes. Any small glass column may be used, such as a glass
pipette with glass wool plug (Chase Scientific Glass, Inc., P1005, 4.5-mL Monstr-Pette,
Fisher Part No. 22-378-893 or equivalent).
6.12 EXTRACT CONCENTRATION SYSTEM - Extracts are concentrated by blowdown with
nitrogen gas using a water bath set at 35° to 40 °C (Meyer N-Evap, Model 111,
Organomation Associates, Inc., or equivalent). Other automated concentration devices may
be used.
6.13 LABORATORY OR ASPIRATOR VACUUM SYSTEM - Sufficient capacity to maintain a
vacuum of approximately 15 to 25 inches of mercury.
6.14 GRADUATED CONICAL SCREW-CAP TEST TUBES - Fifteen-mL capacity (Corning
Part No. 8082-15, Fisher Part No. 05-538-30A, or equivalent), used to collect the eluate from
the carbon cartridges. Also, 40-mL capacity (Kimble Part No. 45200-40, Fisher Part No. 05-
538-33B or equivalent), used to collect eluates from the drying columns.
6.15 GAS CHROMATOGRAPHY MASS SPECTROMETRY SYSTEM (GC/MS)
6.15.1 FUSED SILICA CAPILLARY GC COLUMN - Fused silica capillary column
[20-meter x 0. 18-millimeter (mm) inside diameter (i.d.)] coated with a 0.20-|im
bonded film of poly methylphenyl siloxane (Restek Rtx®-50 or equivalent). Any
column that provides adequate resolution, peak shape, capacity (Sect. 10.2.2.1 and
10.2.2.2), and accuracy and precision (Sect. 9) may be used. A mid-polarity, low-
bleed column is recommended for use with this method to provide appropriate
selectivity, and to minimize mass spectrometric background.
6. 15.2 GC INJECTOR AND OVEN - Equipped for split/splitless injection (Agilent 6890
GC with Agilent 7683 autosampler or equivalent). Some of the analytes included in
this method are very polar and/or subject to thermal breakdown in the injection port.
This effect increases when the injector is not properly deactivated or operated at
excessive temperatures. The injection system must not allow analytes to contact hot
stainless steel or other active surfaces that promote decomposition. The performance
data in Section 17 were obtained using hot, splitless injection with a 2-mm-i.d.
quartz liner (Restek Cat. No. 20914). Other injection techniques such as temperature
programmed injections, cold on-column injections and large volume injections may
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be used if the QC criteria in Section 9 are met. Commercially available inlet
systems, specifically designed for these alternate types of injections, must be used if
these options are selected. The GC system must provide consistent sample injection
volumes and be capable of performing temperature programming at a constant flow
rate, constant linear velocity, or constant pressure.
6.15.2.1 GC SYRINGE - During method development, a 5.0-|iL syringe was used
to inject 0.5-|iL aliquots of standards and extracts (Agilent Cat. No. 5181-
1273 or equivalent).
6.15.3 GC/MS INTERFACE - Interface must allow the capillary column or transfer line
exit to be placed within a few millimeters of the ion source.
6.15.4 MASS SPECTROMETER (MS) - The MS must be capable of electron ionization
and collecting spectra in positive ion mode. The instrument must be capable of
obtaining at least five scans during the chromatographic peaks. Ten to fifteen scans
across chromatographic peaks are recommended. The spectrometer must produce a
mass spectrum that meets all criteria in Table 1 when a solution containing approxi-
mately five nanograms (ng) of decafluorotriphenyl phosphine (DFTPP) is injected
into the GC/MS.
6.15.5 DATA SYSTEM - An interfaced data system is required to acquire, store, and
output MS data. The computer software must have the capability of processing
stored GC/MS data by recognizing a chromatographic peak within a given retention
time window. 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 - 99.999% or better, GC carrier 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 1/3 the MRL
for each compound of interest.
7.1.3 METHANOL - (MeOH) (CASRN 67-56-1) - High purity, demonstrated to be free
of analytes and interferences (Fisher GC Resolv®-grade or equivalent).
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7.1.4 ETHYL ACETATE (EtOAc) (CASRN 141-78-6) - High purity, demonstrated to be
free of analytes and interferences (B & J Brand GC2®, Capillary GC/GC-MS-grade
or equivalent).
7.1.5 DICHLOROMETHANE (DCM), also known as METHYLENE CHLORIDE
(MeCl2) (CASRN 75-09-2) - High purity, demonstrated to be free of analytes and
interferences (B & J Brand GC2®, Capillary GC/GC-MS-grade or equivalent).
7.1.6 SODIUM SULFATE, ANHYDROUS (CASRN 7757-82-6) - Soxhlet extracted with
DCM for a minimum of four hours or heated to 400 °C for two hours in a muffle
furnace. An "ACS grade, suitable for pesticide residue analysis," or equivalent, of
anhydrous Na2SO4 is recommended (Fisher, Cat. No. S415-1 OS or equivalent).
7.1.7 DICHLOROMETHANE/METHANOL 9:1 - Elution solvent. To make 1 L, add
900 mL of DCM to 100 mL of MeOH and mix thoroughly. Store in an amber glass
container.
7.1.8 DICHLOROMETHANE/ETHYL ACETATE 3:1- Drying column rinse solvent.
To make 1 L, add 750 mL of DCM to 250 mL of EtOAc and mix thoroughly. Store
in an amber glass container.
7.1.9 AMMONIUM ACETATE (CASRN 631 -61 -8) - High purity, demonstrated to be
free of analytes and interferences (Sigma Aldrich, Cat. No. A7262 or equivalent).
7.1.10 2.5 M AMMONIUM ACETATE CONCENTRATED STOCK SOLUTION
(192 g/L) - Used to sequester free available chlorine and to buffer field samples. To
prepare 200 mL of solution, add 38.5 g ammonium acetate to a 200-mL volumetric
flask, then add RW to the mark and mix well.
7.1.11 2-CHLOROACETAMIDE (C1CH2CONH2) (CASRN 79-07-2) - Used as an anti-
microbial agent. High purity, demonstrated to be free of analytes and interferences
(Sigma Cat. No. C0267 or equivalent).
7.2 STANDARD SOLUTIONS - When a compound's purity is assayed to be 96% or greater,
the weight can be used without correction to calculate the concentration of the stock standard.
Solution concentrations listed in this section were used to develop this method and are
included only as examples. Stock standard solutions are estimated to be stable for at least
six months if stored at -10 °C or colder. Any fortified or dilute solutions made from the stock
standards are stable for at least 60 days provided they are stored at a temperature <-10 °C and
the stock standard solutions have not exceeded their six month stability period. Although
estimated stability times for standard solutions are given, laboratories should use
accepted QC practices to determine when their standards need to be replaced.
7.2.1 INTERNAL STANDARD SOLUTIONS - This method uses isotopically enriched
ISs, specifically Atrazine-J5(ethyl-J5) (CASRN 163165-75-1; CDN Isotopes Cat.
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No. D4389 or equivalent) and Atrazine-desethyl-J7(isopropyl-J7) (CASRN 6190-65-
4; CDN Isotopes Cat. No. D5639 or equivalent).
7.2.1.1 INTERNAL STANDARD STOCK SOLUTIONS (1000 ng/mL) - Prepare
the stock standards individually by weighing 10 mg of the solid materials
(Atrazine-t/s and Atrazine-desethyl-Jy) into tared 10-mL volumetric flasks
and dilute to volume with EtOAc. Sonication may be required to achieve
full dissolution of the solid materials. Alternatively, commercially
produced standard solutions may be used.
7.2.1.2 INTERNAL STANDARD PRIMARY DILUTION STANDARD (IS PDS)
(200 ng/mL) - Prepare the IS PDS by adding enough of each internal
standard stock solution to a volumetric flask partially filled with EtOAc to
make the final concentrations 200 |j,g/mL when filled to the mark with
EtOAc. During method development, addition of 10 microliters (|jL) of the
IS PDS to each 1.0-mL extract produced a final concentration of 2.0
|ig/mL. Analysts are permitted to use other PDS concentrations and
volumes provided all field samples and calibration standards contain the
same amount of IS, the concentration of the IS added provides adequate
signal to maintain precision, and the volume added has a negligible effect
on the final concentration. Analysts are NOT permitted to use alternate
internal standards.
SURROGATE STOCK STANDARD SOLUTION (1500, 500, or 100 ng/mL) -
This method uses isotopically enriched compounds for surrogate standards,
specifically Atrazine-desethyl-desisopropyl(13C3) (Cambridge Isotope Labs, Cat. No.
CLM-7528-0), Atrazine-desisopropyl-J5(ethyl-J5) (CDN Isotopes Cat. No. D6456),
Cyanazine-J5(jV-ethyl-J5) (CASRN 3397-62-4; CDN Isotopes Cat. No. D6136), and
Simazine-dio(diethyl-dio) (CASRN 220621-39-6; CDN Isotopes Cat. No. D5654).
Concentrations were chosen based on the solubility of these analytes in EtOAc, on
their relative instrument response, and in the case of Atrazine-desethyl-desisopropyl
(13C3), on other important chromatographic considerations (Sect. 10.2.2.2). Prepare
single component SUR stock standards by weighing out approximately 15 mg
Cyanazine-t/s, and 5.0 mg of Atrazine-desisopropyl-t/s and Simazine-t/io solid
materials using an analytical balance into separate, tared 10-mL volumetric flasks.
Dilute to volume with EtOAc. Atrazine-desethyl-desisopropyl (13C3) surrogate is
much less soluble in EtOAc and is prepared by weighing out approximately 5.0 mg
of the solid using an analytical balance into a tared 50-mL volumetric flask and
diluting to volume with EtOAc; the Atrazine-desethyl-desisopropyl (13C3) used
during method development was custom synthesized by Cambridge Laboratories.
Analysts are NOT permitted to use alternate surrogates.
7.2.2.1 SURROGATE PRIMARY DILUTION STANDARDS (SUR PDS) -
Prepare a single SUR PDS that contains Simazine-t/io and Atrazine-
desisopropyl-t/s at 200 ng/mL, and Cyanazine-t/s at 500 |j,g/mL by making
appropriate dilutions of the SUR stock standard solutions into ethyl acetate.
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During method development, the Atrazine-desethyl-desisopropyl (13C3)
SUR stock was used without further dilution to fortify samples prior to
extraction (Sect. 11.2.2) and to prepare calibration standards (Sect. 7.2.4).
7.2.3 ANALYTE STANDARD SOLUTIONS - Obtain the analytes listed in the table in
Section 1.1 as neat standards. Prepare the analyte stock and Primary Dilution
Standards as described below. Alternatively, commercially produced standard
solutions may be used.
7.2.3.1 ANALYTE STOCK STANDARD - Prepare the stock standards
individually by weighing 10-20 mg of the solid materials using an
analytical balance into tared 5-mL, 10-mL, or larger volumetric flasks and
diluting to volume with EtOAc. Atrazine-desethyl-desisopropyl exhibits
limited solubility in EtOAc and must be prepared at a concentration of
<100 |j,g/mL. The table below summarizes the concentration of the analyte
stock standards used during method development. In some cases,
sonication is required to achieve full dissolution of the neat materials.
Analyte
Atrazine
Atrazine-desethyl
Atrazine-desisopropyl
Atrazine-desethyl-desisopropyl
Cyanazine
Propazine
Simazine
Terbuthylazine
Terbuthylazine-desethyl
Prometon
Prometryn
Ametryn
Simetryn
Analyte Stock Standard*
(Hg/mL)
2000
1000
500
100
2000
2000
500
2000
850
1200
900
1200
840
Manufacturer, Part No.**
Chem Service, PS-380
Chem Service, MET-380B
Chem Service, MET-58A
Chem Service, MET-58C
Chem Service, PS-387
Chem Service, PS-385
Chem Service, PS-58
Chem Service, PS-413
Chem Service, MET-413A
Chem Service, PS-386
Chem Service, PS-384
Chem Service, PS-383
Chem Service, PS-3 81
* Analyte stock standard concentrations used during method development. Some analytes are near their solubility
limits at the storage temperature and required sonication to dissolve.
** Other manufacturer's standards are allowed as long as they have acceptable purity.
7.2.3.2 ANALYTE PRIMARY DILUTION STANDARD (50 ng/mL) - The ana-
lyte PDS is used to prepare the CALs and to fortify the LFBs, LFSMs and
LFSMDs with the method analytes. The analyte PDS is prepared by adding
appropriate volumes of the of the analyte stock solutions (except Atrazine-
desethyl-desisopropyl) into a single volumetric flask and diluting to volume
such that the final concentration is 50 |j,g/mL. Because the concentration of
Atrazine-desethyl-desisopropyl in the analyte stock is low due to its limited
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solubility in EtOAc, use the analyte stock directly as an analyte PDS
solution in the steps that follow.
7.2.4 CALIBRATION STANDARDS - Prepare a calibration curve of at least five levels
from dilutions of the analyte PDS in EtOAc. The preparation scheme, with
concentrations of CALs that were used to collect data in Section 17, is presented in
the table below. A constant concentration of each IS and SUR analyte (in the range
of 1 to 5 |ig/mL) is added to each calibration solution. For example, add 20 jiL of
the IS PDS (Sect. 7.2.1.2) and 20 |iL of the multi-component SUR PDS (Sect.
7.2.2.1) to each CAL. For the surrogate Atrazine-desethyl-desisopropyl (13C3), add
20 |jL of the SUR. stock standard (Sect. 7.2.2). The lowest concentration CAL must
be at or below the MRL. The CAL standards may also be used as CCCs. The
standards must be stored at -10 °C or lower.
CAL
Level
1
2
3
4
5
6
7
8
Analyte PDS*
(ug/mL)
50
50
50
50
50
50
50
50
Analyte PDS Volume**
(uL)
4
8
12
20
30
40
80
200
Final CAL
Volume (mL)
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
CAL
(us/mL)
0.10
0.20
0.30
0.50
0.75
1.00
2.00
5.00
* For atrazine-desethyl-desisopropyl, the analyte stock standard was used at a concentration of 100 (ig/mL.
** For atrazine-desethyl-desisopropyl, 1A of the volume reported in this table was used.
7.2.5 GC/MS TUNE CHECK SOLUTION (5 jig/mL) - Prepare a DFTPP (CASRN 5074-
71-5) solution in DCM. DFTPP is more stable in DCM than in acetone or EtOAc.
Store this solution in an amber glass screw cap vial at -10 °C or lower.
8. SAMPLE COLLECTION, PRESERVATION, AND STORAGE
8.1 SAMPLE COLLECTION
8.1.1 Prior to shipment to the field, the ammonium acetate solution and 2-chloroacetamide
must be added to each sample bottle. 250-mL sample bottles are recommended. For
this sample volume, add 2.0 mL of the ammonium acetate concentrated stock (Sect.
7.1.10) and 500 mg of 2-chloroacetamide. These reagents may be added in the field.
However, the preservatives must be added to the container prior to sample collection.
If other collection volumes are used, adjust the amount of the preservatives so that
the final concentrations of ammonium acetate and 2-chloroacetamide in the sample
containers are 1.5 g/L (20 millimolar, mM) and 2.0 g/L, respectively. Cap the bottles
to avoid loss of the preservation reagents.
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NOTE: The extraction procedure was developed using a 250-mL sample volume.
Although the method performed well at this volume in matrices containing high
levels of total organic carbon (TOC), larger extraction volumes could conceivably
cause breakthrough for field samples with high TOC levels. For this reason, sample
size must not exceed the recommended volume by more than 10%. Smaller sample
volumes, although not subject to breakthrough, may decrease method sensitivity
making it more difficult to confirm the MRL (Sect. 9.2.4).
8.1.2 When sampling from a cold water tap, open the tap and allow the system to flush
until the water temperature has stabilized (usually 3 to 5 minutes). Collect a repre-
sentative sample from the flowing system using a beaker of appropriate size. Use
this bulk sample to generate individual samples as needed. Transfer a volume of at
least 245 mL into each collection container, cap the container, and invert it several
times to mix the sample with the preservatives. Care must be taken not to overfill
the bottle and flush out the preservation reagents. Samples do not need to be head-
space free.
8.1.3 When sampling from an open body of water, fill a beaker with water sampled from a
representative area. Use this bulk sample to generate individual samples as needed.
8.2 FIELD DUPLICATES - Collect enough Field Duplicates to fulfill QC requirements for
LFSMs and LFSMDs (at least three identical samples).
8.3 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 until extraction. Samples must not be frozen.
8.4 SAMPLE HOLDING TIMES - Samples should be analyzed as soon as possible. Samples
that are collected and stored as described in Sections 8.1 and 8.3 may be stored prior to
analysis for a maximum of 28 days. Extracts may be held for a maximum of 28 days prior to
analysis, if they are stored at -10 °C or lower.
9. QUALITY CONTROL
9.1 QC requirements include the IDC and ongoing QC requirements. This section describes each
QC parameter, its required frequency, and the performance criteria that must be met in order
to meet EPA quality objectives. The QC criteria discussed in the following sections are
summarized in Section 17, Tables 10 and 11. These QC requirements are considered the
minimum acceptable QC criteria. Laboratories are encouraged to institute additional QC
practices to meet their specific needs.
9.2 INITIAL DEMONSTRATION OF CAPABILITY - 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. Requirements for the IDC are
described in the following sections and are summarized in Table 10.
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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.
9.2.2 DEMONSTRATION OF PRECISION - Prepare, extract and analyze four to seven
replicate LFBs. Fortify these samples near the midrange of the initial calibration
curve. Ammonium acetate and 2-chloroacetamide must be added to the samples as
described in Section 8.1. The percent relative standard deviation (RSD) of the
concentrations of the replicate analyses must be <20% for all analytes.
n, _ „_ Standard Deviation of Measured Concentrations ,
%RSD = x 100
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 +30% of the true value.
.. _. Average Measured Concentration , ^
% Recovery = x 100
Fortified Concentration
9.2.4 MINIMUM REPORTING LEVEL (MRL) CONFIRMATION - Establish a target
concentration for the MRL based on the intended use of the method. Analyze an
initial calibration following the procedures in Section 10.2. The lowest CAL used to
establish the initial calibration (as well as the low-level CCC) must be at or below
the concentration of the MRL. Establishing the MRL concentration too low may
cause repeated failure of ongoing QC requirements. Confirm the MRL following the
procedure outlined below.
9.2.4.1 Fortify, extract and analyze seven replicate LFBs at or below the target
MRL concentration. Ammonium acetate and 2-chloroacetamide must be
added to the samples as described 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
HRPIR = 3.9638
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 PIR (PIR = Mean ± HRPIR)
meet the upper and lower recovery limits as shown below.
The Upper PIR Limit must be <150% recovery.
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Mean + HRprrf
xlOO<150%
Fortified Concentration
The Lower PIR Limit must be >50% recovery.
Mean - HRprrf
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 - Analyze a mid-level QCS (Sect. 9.3.9) to
confirm the accuracy of the primary CALs.
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 labora-
tory 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 (both the sample
extraction and the GC analyses must be done over a period of at least three days).
Prepare at least seven replicate LFBs. Use the solutions described in Section 7.2 to
fortify at a concentration estimated to be near the DL. This concentration may be
estimated by selecting a concentration at two to five times the noise level.
Ammonium acetate and 2-chloroacetamide must be added to the samples as
described in Section 8.1. Process the seven replicates through all steps in Section 11.
NOTE: If an MRL confirmation data set meets these requirements, DLs may be
calculated from the MRL confirmation data, and no additional analyses are
necessary.
Calculate the DL using the following equation:
DL= St(n.iji.a = 0.99)
where:
t(n-i,i-a = 0.99)= Student's t value for the 99% confidence level with n-1 degrees of
freedom
n = number of replicates
S = standard deviation of replicate analyses.
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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 11 summarizes these
requirements.
9.3.1 LABORATORY REAGENT BLANK - An LRB is required with each Extraction
Batch. If within the retention time window of any analyte, the LRB produces a peak
that would prevent the determination of that analyte, determine the source of
contamination and eliminate the interference before processing samples.
Background from analytes or contaminants that interfere with the measurement of
method analytes must be less than 1/3 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.
NOTE: Subtracting blank 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 any background
interference. Therefore, blank contamination levels may be estimated by extrapola-
tion, when the concentration is below the MRL.
9.3.2 CONTINUING CALIBRATION CHECK - 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 10.3 for concentration requirements and acceptance
criteria.
9.3.3 LABORATORY FORTIFIED BLANK - An LFB is required with each Extraction
Batch. The fortified concentration of the LFB must be rotated between low,
medium, and high concentrations from batch to batch. The low concentration LFB
must be at or below the MRL. Similarly, the high concentration LFB must be near
the high end of the calibration range established during the initial calibration (Sect.
10.2). Results of the low-level LFB analyses must be within +50 of the true value.
Results of the medium and high-level LFB analyses must be within +30% of the true
value. If the LFB results do not meet these criteria, then all data for the problem
analyte(s) must be considered invalid for all samples in the Extraction Batch.
9.3.4 MS TUNE CHECK - The procedure for conducting the MS Tune Check is found in
Section 10.2.1. Acceptance criteria for the MS Tune Check are summarized in Sec-
tion 17, Table 1. The MS Tune Check must be performed each time a major change
is made to the mass spectrometer, and prior to establishing and/or re-establishing an
initial calibration (Sect. 10.2). Daily DFTPP analysis is not required.
9.3.5 INTERNAL STANDARDS - The analyst must monitor the peak areas of the ISs in
all injections of the Analysis Batch. The IS response (peak area) in any chromato-
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graphic 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 in a chromatographic run does not
meet these criteria, examine the areas of the ISs in the CCCs, and take corrective
action such as recalibration, verifying the integrity of the IS solution, and servicing
the GC/MS system. Reanalyze the extract in a subsequent Analysis Batch.
9.3.5.1 If the reinjected aliquot produces an acceptable IS response, report results
from that analysis.
9.3.5.2 If the reinjected extract fails again, extraction of the sample may need to be
repeated provided a sample is available and still within the holding time.
Otherwise, report results obtained from the reinjected extract, but annotate
as "suspect/IS recovery." Alternatively, collect a new sample and
reanalyze.
9.3.6 SURROGATE RECOVERY - The surrogate analytes are fortified into all field sam-
ples and QC samples prior to extraction. Calculate the percent recovery (%R) for
each surrogate using the equation
( A\
%R= — xlOO
UJ
where A = calculated surrogate concentration for the QC or field sample, and B =
fortified concentration of the surrogate analyte.
9.3.6.1 Surrogate recovery must be in the range of 70 to 130%. When a surrogate
fails to meet this criterion, evaluate the recovery of the surrogates in the
CCCs, the integrity of the CAL solutions, and take corrective action such as
recalibration and servicing the GC/MS system. Reanalyze the extract in a
subsequent Analysis Batch.
9.3.6.2 If the extract reanalysis meets the surrogate recovery criterion, report only
data for the reanalyzed extract.
9.3.6.3 If the extract reanalysis fails the 70 to 130% recovery criterion after
corrective action, extraction of the sample must be repeated provided a
sample is available and still within the holding time. If the re-extracted
sample also fails the recovery criterion, report all data for that sample as
"suspect/surrogate recovery." Alternatively, collect a new sample and
reanalyze.
9.3.7 LABORATORY FORTIFIED SAMPLE MATRIX - A minimum of one LFSM is
required in each Extraction Batch. The native concentrations of the analytes in the
sample matrix must be determined in a separate aliquot and the measured value in
the LFSM corrected for the native concentrations. If a variety of different sample
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matrices are analyzed regularly, for example drinking water from groundwater 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 appropriate amounts
of the analyte PDS (Sect. 7.2.3.2) and DACT PDS (Sect, 7.2.3.1). 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.
9.3.7.2 Calculate the %R using the equation
C
A = measured concentration in the fortified sample
B = measured concentration in the unfortified sample
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 and the
LFB, 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 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 - A minimum of one FD or LFSMD is required in each Extraction
Batch. If method analytes are not routinely observed in field samples, analyze an
LFSMD rather than an FD.
9.3.8.1 Calculate the relative percent difference (RPD) for duplicate measurements
(FDi and FD2) using the equation
FD, -FD
(FD, +FD2)/2
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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 for any analyte falls outside the designated range, and the
laboratory performance for the analyte is shown to be in control in the CCC
and the LFB, 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 an FD, calculate the RPD for duplicate
LFSMs (LFSM and LFSMD) using the equation
RPD =
LFSM-LFSMDl
(LFSM + LFSMD)/2
xlOO
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 for any
analyte falls outside the designated range, and the laboratory performance
for the analyte is shown to be in control in the CCC and the LFB, the
precision is judged matrix influenced. The result from the unfortified
sample is labeled "suspect/matrix."
9.3.9 QUALITY CONTROL SAMPLE - A QCS is required if an alternate commercial
source is available for the method analytes. A QCS must be evaluated as part of the
IDC (Sect. 9.2.5) and each time new stock standard solutions are prepared. If
standards are prepared infrequently, analyze a QCS at least quarterly. The QCS must
be fortified near the midpoint of the calibration range and analyzed as a CCC. The
acceptance criteria for the QCS are the same as for the mid- and high-level CCCs
(Sect. 10.3.2). 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 GC column, GC conditions and MS conditions. The analyst is not permitted to modify
sample collection and preservation, sample extraction conditions, or QC requirements of the
method.
9.4.1 Each time method modifications are made, the analyst must repeat the procedures of
the IDC (Sect. 9.2) and verify that all QC criteria can be met in ongoing QC samples
(Sect. 9.3).
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9.4.2 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 per-
form acceptably in the IDC, which is conducted in RW, could fail ongoing method
QC requirements in real matrices due to common method interferences. If, for
example, the laboratory analyzes finished waters from both surface and groundwater
municipalities, this requirement can be accomplished by assessing precision and
accuracy (Sects. 9.2.2 and 9.2.3) in a surface water with moderate to high TOC (e.g.,
2 mg/L or greater) and a hard groundwater (e.g., hardness greater than 250 mg/L).
9.4.3 The results of Sections 9.4.1 and 9.4.2 must be appropriately documented by the
analyst and must be independently verified by the laboratory's quality assurance
officer prior to analyzing field samples. When implementing method modifications,
it is the responsibility of the laboratory to closely review the results of ongoing QC,
and in particular, results associated with the CCCs (Sect. 10.3) and the IS area counts
(Sect. 9.3.5). If repeated failures are noted, the modification must be abandoned.
10. CALIBRATION AND STANDARDIZATION
10.1 Demonstration and documentation of acceptable analyte calibration is required before
performing the IDC (Sect. 9.2) and prior to analyzing field samples. The MS Tune Check
and the initial GC/MS calibration should be repeated each time a major instrument
modification or maintenance is performed.
10.2 GC/MS INITIAL CALIBRATION - An initial calibration requires establishing proper
GC/MS conditions, confirming the instrument meets the DFTPP tune check criteria, and the
preparation and analysis of at least five CALs to determine the calibration curve. Calibration
must be performed using peak areas and the IS technique. Calibration using peak heights and
external standard calibration are not permitted.
10.2.1 MS TUNE/MS TUNE CHECK- Calibrate the mass and abundance scales of the MS
with calibration compounds and procedures prescribed by the manufacturer with any
modifications necessary to meet tuning requirements. Inject five ng or less of
DFTPP (Sect. 7.2.5) into the GC/MS system. Acquire a mass spectrum that includes
data for mass/charge ratio (m/z) 45 to 450. Use a single spectrum of the DFTPP
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 DFTPP peak. If the
DFTPP mass spectrum does not meet all criteria in Table 1, the MS must be retuned
and adjusted to meet all DFTPP criteria before proceeding with the initial calibration.
10.2.2 GC/MS INSTRUMENT CONDITIONS - Operating conditions used during method
development are described below. GC/MS operating conditions are summarized in
Table 2 (Sect. 17). Conditions different from those described may be used if the
method modification QC criteria in Section 9.4 are met. Alternate conditions include
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appropriate GC columns, temperature programs, MS conditions, and injection
techniques and volume, such as cold on-column and direct injection port liners
and/or large volume injection techniques. Commercially available GC inlets must be
used for these alternate injection techniques.
10.2.2.1 A narrow bore (0.18-mm i.d.) GC column and a relatively fast temperature
program can be used in order to minimize run time (total run time during
method development was 12.2 minutes) without jeopardizing resolution.
This chromatographic technique requires an MS capable of scanning and
storing sufficient numbers of spectra per second in order to record the
recommended number of scans per peak (e.g., at least 5, but 10 to 15 scans
are recommended). Instruments that are not capable of achieving these fast
scan rates must employ a larger-diameter column (e.g., 0.25-mm i.d.) In
addition, instruments that are being used with relatively fast temperature
programs must have GC oven heaters that are sufficiently powerful enough
to perform fast temperature ramping.
10.2.2.2 The method analyte, Atrazine-desethyl-desisopropyl, is the fully
dealkylated form of the parent and as a consequence is very polar. It is
often referred to as diaminochlorotriazine (DACT) in the literature. Its
polar nature and its low solubility in the EtOAc solvent and many GC
stationary phases make this analyte very difficult to chromatograph.
Several GC columns of varying polarity were investigated, as were various
injection volumes. The recommended column is a mid-polarity column
that has low bleed and performed well for this challenging analyte. Solvent
overloading and/or high concentrations of the 13C-labeled DACT surrogate
can lead to overloading of the column phase. When this happens, the
DACT peak is broad and asymmetric.
10.2.2.3 Many of the triazine degradates are polar and subject to breakdown and/or
adsorption onto active sites in the inlet. A straight, 2-mm quartz liner was
determined to be optimal for this method. Even with this liner, a number of
analytes exhibited a loss in sensitivity at low concentrations.
10.2.3 CALIBRATION STANDARDS - Prepare a set of at least five CAL standards as de-
scribed in Section 7.2.3. The lowest concentration of the CALs must be at or below
the MRL. 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.
10.2.4 CALIBRATION - Calibrate the GC/MS system using peak areas and the IS tech-
nique. Fit the calibration points with either a linear regression or quadratic
regression (response vs. concentration). Weighting may be used. Forcing the
calibration curve through the origin is not recommended. Suggested quantitation
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ions and retention times for analytes obtained during method development are listed
in Table 3.
10.2.5 CALIBRATION ACCEPTANCE CRITERIA - The calibration is validated by
calculating the concentration of the analytes from each of the analyses used to
generate the calibration curve using the regression equations. Calibration points that
are
-------
QC elements are included (Sect. 9). This section describes the procedure used to extract and
analyze field and QC samples.
11.2 SAMPLE PREPARATION
11.2.1 Allow field samples to reach room temperature prior to extraction. Before
extraction, mark the level of the sample on the outside of the sample bottle for later
sample volume determination. If using weight to determine volume (Sect. 11.3.2.7),
weigh the full sample bottle before extraction.
11.2.2 Add an aliquot of the SUR PDS to each sample to be extracted. For method
development work, a 10-|iL aliquot of the three-component SUR PDS (Sect. 7.2.2.1)
and 10 jiL of the atrazine-desethyl-desisopropyl(13C3) SUR stock (Sect. 7.2.2) were
added to each 250-mL field and QC sample.
11.2.3 Fortify LFBs, LFSMs, or LFSMDs, with an appropriate volume of analyte PDS
(Sect. 7.2.3.2) and the atrazine-desethyl-desisopropyl stock standard (Sect. 7.2.3.1).
Cap and invert each sample several times to mix.
11.2.4 Proceed with sample extraction using SPE carbon cartridges.
11.3 CARTRIDGE SPE PROCEDURE
11.3.1 CARTRIDGE CLEANING AND CONDITIONING - Proper cleaning and
conditioning of the solid-phase sorbent can have a marked effect on method
precision and accuracy.
11.3.1.1 Set up extraction columns on the SPE vacuum manifold. Using low
vacuum (approximately 1 to 2 inches Hg), rinse each cartridge with two
6-mL aliquots of DCM, aspirating completely.
11.3.1.2 Rinse each cartridge with a 6-mL aliquot of MeOH, being careful not to let
the bed to go dry. Follow this with a 6-mL aliquot of RW, again being
careful not to let the bed go dry.
11.3.2 SAMPLE EXTRACTION
11.3.2.1 Add an additional 4 mL of RW to each cartridge and attach the sample
transfer lines. This additional volume prevents the SPE cartridge bed from
going dry while the dead volume in the transfer lines is being filled.
Extract samples at a cartridge flow rate of approximately 10 mL/minute.
NOTE: Faster flow rates have not been tested and could cause breakthrough.
11.3.2.2 Dry the cartridges under high vacuum for 10 seconds. Release the vacuum,
then add a 0.25-mL aliquot of MeOH to each cartridge. Draw the MeOH to
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waste with brief vacuum, then dry the cartridges under high vacuum for
10 minutes.
11.3.2.3 Elute the analytes from the cartridges into 15-mL conical tubes with 2 mL
of EtOAc followed by two, 6-mL aliquots of 9:1 DCM/MeOH. Allow the
cartridge beds to briefly soak in solvent before drawing the solvent through
the cartridges.
11.3.2.4 Dry the eluate by passing it through approximately 3 grams of anhydrous
Na2SC>4 collecting it in a 40-mL centrifuge tube. (A Pasteur pipette may be
used for a drying column.) Pre-rinse the Na2SO4with a 1-mL aliquot of 3:1
DCM/EtOAc. Rinse the 15-mL conical tube with another 1-mL aliquot of
3:1 DCM/EtOAc and pass this through the anhydrous Na2SC>4 drying
column, collecting it in the same 40-mL centrifuge tube. At this point in
the procedure, the dried extracts may be stored overnight in the 40-mL
tubes at -10 °C, if desired.
11.3.2.5 Thermostat the 40-mL tubes at approximately 35 °C in a water bath, and
blow down the eluates under a stream of nitrogen gas to less than 1 mL (but
no less than 1A mL).
11.3.2.6 Transfer the concentrated eluates to 1-mL volumetric tubes. Rinse the
conical tube with a small volume of EtOAc, and transfer the rinseate to the
volumetric. Add IS solution, and adjust to volume. During method
development, a 10-[iL aliquot of the IS PDS (Sect. 7.2.1.2) was added to
each extract. Transfer the extracts to autosampler vials and store in a
freezer (<-10°C).
11.3.2.7 SAMPLE VOLUME OR WEIGHT DETERMINATION - Use a graduated
cylinder to measure the volume of water required to fill the original sample
bottle to the mark made prior to extraction (Sect. 11.2.1). Determine the
volume of each sample to the nearest 2 mL for use in the final calculations
of analyte concentration (Sect. 12.3). If using weight to determine volume,
reweigh the empty sample bottle. From the weight of the original sample
bottle measured in Section 11.2.1, subtract the empty bottle weight.
11.4 ANALYSIS OF SAMPLE EXTRACTS
11.4.1 Establish GC/MS operating conditions equivalent to those summarized in Table 2 of
Section 17. Confirm that compound separation and resolution are similar to those
summarized in Table 3 and illustrated in Figure 1 (Sect. 17).
11.4.2 Establish a valid initial calibration following the procedures outlined in Section 10.2
or confirm that the calibration is still valid by analyzing a CCC as described in
Section 10.3.
523-25
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11.4.3 Analyze aliquots of field samples and QC samples. Analyze CCCs at the required
frequency alternating concentrations as described in Section 10.3. The GC/MS condi-
tions used to acquire the initial calibration must be used for all sample analyses. The
Laboratory Reagent Blank should be the first sample analyzed after the opening CCC.
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. This is true whether or not an initial
calibration is analyzed. After 24 hours or 20 field samples, the low-level CCC must be
repeated to begin a new Analysis Batch. Do not count QC samples (LRBs, LFBs, 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 a spectrum matching criterion when collecting data in
full scan mode based on the comparison of field sample spectra (after background
subtraction if necessary) to reference spectra in the user-created database. This
database must 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.
12.2 COMPOUND CONFIRMATION - In general, all ions that are present above 30% relative
abundance in the mass spectrum of the user-generated database should be present in the mass
spectrum of the sample component and should agree within an absolute 20% of the relative
abundance in the reference spectrum. For example, if an ion has a relative abundance of 30%
in the standard spectrum, its abundance in the sample spectrum should be in the range of 10
to 50%. Some ions, particularly the molecular ion, are of special importance, and should be
evaluated even if they are below 30% relative abundance.
523-26
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NOTE: Compound identification is more challenging when sample components are not resolved
chromatographically and produce mass spectra containing ions contributed by more than one
compound. 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 QUANTITATION - Calculate analyte concentrations using the multipoint
calibration established in Section 10.2. Report only those values that fall between the MRL
and the highest CAL.
12.3.1 EXCEEDING CALIBRATION RANGE - The analyst must not extrapolate beyond
the established calibration range. If an analyte result exceeds the range of the initial
calibration curve, the extract may be diluted using EtOAc with the appropriate
amount of IS added to match the original level, and the diluted extract reinjected.
Acceptable surrogate performance must be determined from the undiluted sample
extract. Incorporate the dilution factor into final concentration calculations. The
resulting data must be documented as a dilution, and the reported MRLs must reflect
the dilution factor.
12.3.2 Calculations must use all available digits of precision, but final reported concentra-
tions 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.
12.3.3 Prior to reporting data, the chromatograms must be reviewed for any incorrect peak
identifications or poor integrations.
123.4 Prior to reporting data, the laboratory is responsible for assuring that QC require-
ments have been met and that any appropriate qualifier is assigned.
13. METHOD PERFORMANCE
13.1 PRECISION, ACCURACY AND LOWEST CONCENTRATION MINIMUM
REPORTING LIMITS - Table 4 presents the DL and LCMRL values obtained at EPA.
LCMRLs were determined and calculated using a procedure described elsewhere.1 Single
laboratory precision and accuracy data are presented for three water matrices: RW (Table 5),
chlorinated surface water (Table 6), and chlorinated groundwater (Table 7). Figure 1
displays a representative chromatogram fortified at a high concentration in chlorinated
groundwater.
13.2 SECOND LABORATORY EVALUATION - The performance of this method was demon-
strated by a second laboratory, with results similar to those reported in Section 17. The
authors wish to acknowledge the work of Ms. Diane Gregg and Ms. Meredith Clarage of the
523-27
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U.S. EPA Region 6 Laboratory, Houston, TX, and Mr. Frederick Feyerherm of Agilent, Inc.,
for conducting the second laboratory evaluation.
13.3 SAMPLE STORAGE STABILITY STUDIES - Chlorinated surface water samples, fortified
with method analytes at 5.0 |ig/L, were preserved and stored over a 28-day period as
specified in Section 8. The analyte recovery and the precision of three replicate analyses of
the stored samples, conducted after 0, 7, 14, 21, and 28 days of storage are presented in
Section 17, Table 8. These data were used to determine the 28-day holding time.
13.4 EXTRACT STORAGE STABILITY STUDIES - Extract storage stability studies were
conducted for extracts obtained from a chlorinated surface water fortified at 5.0 |ig/L. The
precision and average analyte recovery of triplicate injections conducted after 0, 7, 14, 21,
and 28 days of storage are presented in Table 9. These data were used to confirm the 28-day
holding time.
13.5 PROBLEM COMPOUNDS
13.5.1 DACT: Atrazine-desethyl-desisopropyl or DACT is subject to hydrolysis at both
high (>9) and low (<5) pH but has acceptable stability in neutral aqueous solutions.
DACT is also degraded in the presence of free available chlorine, but stable in the
presence of chloramines. Ammonium acetate mitigates both of these modes of loss
during sample storage, and has sufficient buffer capacity at 20 mM to buffer finished
groundwaters with relatively high pH that also have high buffer capacity. The low
solubility of DACT in many common low-polarity GC phases (e.g., DB-1, DB-5)
leads to phase overloading and distortion of the DACT peak shape at even modest
column loadings. The recommendations for the Rtx®-50 GC column as well as a
0.5-|iL injection volume are based on these factors. Even with this mid-polarity
phase, coupled with a sub-sized injection volume, it is advisable to lower the
fortification concentration of the 13C3-DACT surrogate to 4 |ig/L in field samples (or
1 |j,g/mL in the extract) to minimize peak distortion at higher calibration levels.
13.5.2 Cyanazine, which is the last eluting analyte, is prone to degradation in the injection
port. It also has the highest LCMRL and more variable recovery than any other
analyte in this method. For these reasons, a relatively high spike level of 20 |ig/L for
the surrogate, Cyanazine-t/5; is recommended.
13.6 MATRIX ENHANCED SENSITIVITY - Method analytes may exhibit "matrix-induced
chromatographic response enhancement."7"11 That is, compounds susceptible to GC inlet
adsorption or thermal degradation suffer more breakdown when injected in a "cleaner"
matrix. The injection of a "dirty" sample extract coats surfaces with matrix components and
"protects" the problem compounds from decomposition or adsorption. As a result, a
relatively greater response is observed for analytes in sample extracts than in calibration
solutions. Compounds that exhibit this phenomenon often give analytical results that exceed
100% recovery in fortified extracts, especially at low concentrations. Analyte areas in CCCs
may increase after the injection of several "real samples" compared to injections during a
calibration sequence at the beginning of an Analysis Batch. If these symptoms are observed,
523-28
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more frequent recalibration is recommended. The analyst may also choose to condition the
injection port after maintenance or prior to starting an Analysis Batch by injecting a few
aliquots of a field sample extract. Matrix effects are also mitigated by using a quartz inlet
liner and by minimizing the liner volume as much as is practical (Sect. 6.15.2).
14. POLLUTION PREVENTION
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.
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 regula-
tions, 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. I; Hallberg, G. R.; Munch D. I; Frebis, C. P.;
Hedrick, E. J.; Krop, R. A. Statistical Procedures for Determination and Verification of
Minimum Reporting Levels for Drinking Water Methods. Environ. Sci. Technol. 2006; 40,
281-288.
2. Glaser, J.A.; Foerst, D.L.; McKee, G.D.; Quave, S.A.; Budde, W.L. Trace Analyses for Waste-
waters. Environ. Sci. Technol. 1981; 15, 1426-1435.
3. Center for Disease Control, National Institute for Occupational Safety and Health. Guidelines,
Recommendations, and Regulations for Handling Antineoplastic Agents.
http://www.cdc.gov/niosh/topics/antineoplastic/pubs.htmltfb.
4. Occupational Exposures to Hazardous Chemicals in Laboratories, 29 CFR 1910.1450,
Occupational Safety and Health Administration (1990).
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5. Safety in Academic Chemistry Laboratories; American Chemical Society Publication,
Committee on Chemical Safety; 7th Edition, Washington D.C., 2003.
6. Panshin, S. Y.; Carter, D. S.; Bayless, E. R. Analysis of Atrazine and Four Degradation
Products in the Pore Water of the Vadose Zone, Central Indiana. Environ. Sci. Technol. 2000;
34,2131-2137.
7. Erney, D. R.; Gillespie, A. M.; Gilvydis, D. M.; Poole, C. F. Explanation of the Matrix-
Induced Chromatographic Response Enhancement of Organophosphorous Pesticides During
Open Tubular Column Gas Chromatography with Splitless or Hot On-Column Injection and
Flame Photometric Detection. J. Chromatogr. 1993; 638, 57-63.
8. Mol, H. G. J.; Althuizen, M.; Janssen, H.; Cramers, C. A. Brinkman, U.A.Th. Environmental
Applications of Large Volume Injection in Capillary GC Using PTV Injectors. J. High Resol.
Chromatogr. 1996; 19, 69-79.
9. Erney, D. R.; Pawlowski, T. M.; Poole, C. F. Matrix Induced Peak Enhancement of Pesticides
in Gas Chromatography. J. High Resol. Chromatogr. 1997; 20, 375-378.
10. Hajslova, J.; Holadova, K.; Kocourek, V.; Poustka, J.; Godula, M.; Cuhra, P.; Kempny, M.
Matrix Induced Effects: A Critical Point in the Gas Chromatographic Analysis of Pesticide
Residues. J. Chromatogr. 1998; 800, 283-295.
11. Wylie, P.; Uchiyama, M. Improved Gas Chromatographic Analysis of Organophosphorous
Pesticides with Pulsed Splitless Injection. J. AOACInternational. 1996; 79, 2, 571-577.
12. Determination of Selected Pesticides and Flame Retardants in Drinking Water by Solid Phase
Extraction and Capillary Column Gas Chromatography /Mass Spectrometry; U.S. EPA
Method 527, EPA 815-R-05-005.
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17. TABLES, DIAGRAMS, FLOWCHARTS, AND VALIDATION DATA
TABLE 1. ION ABUNDANCE CRITERIA FOR BIS(PENTAFLUOROPHENYL)PHENYL
PHOSPHINE, (DECAFLUOROTRIPHENYL PHOSPHINE, DFTPPf
Mass (m/z)
68
69
70
197
198
199
365
441
442
443
Relative Abundance Criteria
<2%ofWz69
Present
<2%ofWz69
<2% of m/z 198
Present
5-9% of m/z 198
>1% of base peak
<150%ofWz443
Present
15-24% of m/z 442
Purpose of Checkpoint13
Low-mass resolution
Low-mass resolution
Low-mass resolution
Mid-mass resolution
Mid-mass resolution and sensitivity
Mid-mass resolution and isotope ratio
Baseline threshold
High-mass resolution
High-mass resolution and sensitivity
High-mass resolution and isotope ratio
These ion abundance criteria have been developed specifically for target compound analysis as
described in this method. Adherence to these criteria may not produce spectra suitable for
identifying unknowns by searching commercial mass spectral libraries. If the analyst intends to use
data generated with this method to identify unknowns, adherence to stricter DFTPP criteria as
published in previous methods12 is suggested.
All ions are used primarily to check the mass accuracy of the mass spectrometer and data system,
and this is the most important part of the performance test. The three resolution checks, which
include natural abundance isotope ratios, constitute the next most important part of the performance
test, followed by the correct setting of the baseline threshold, as indicated by the presence of m/z
365.
523-31
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TABLE 2. GC/TOF-MS CONDITIONS (LECO Model Pegasus III, GC/TOF-MS)
Chromatographic Conditions
Column: Restek Rtx-50, 20 meters x 0.18 mm i.d., 0.20-|im film thickness
Injection Liner: 2-mm quartz
Injection Volume: 0.50 |jL; Syringe: 5.0 jiL
Injection Port Temperature: 260 °C
Split Delay: 0.33 minute
Carrier Gas: He, 1.0 mL/minute, constant flow, initial head-pressure 27 pounds per square inch
Temperature Program: initial oven temperature of 120 °C hold for 2 minutes, then ramp at
25 °C/minutes to 250 °C and hold for 5 minutes
Total Run Time: 12.2 minutes
TOF-MS Conditions
Scan Delay: 375 seconds
Scan End: 520 seconds
Mass Scan Range: m/z 45 to 260
Mass Defect: 0
Detector Voltage: 1600 volts
Acquisition Rate: 20 spectra/second
Source Temperature: 200 °C
523-32
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TABLE 3. RETENTION TIMES, SUGGESTED QUANTITATION IONS, AND
RECOMMENDED INTERNAL STANDARD REFERENCES
Analyte
Atrazine-desethyl-desisopropyl-13C3 (SUR)
Atrazine-desethyl-desisopropyl
Terbuthylazine-desethyl
Atrazine-desethyl-Jy (IS#1)
Atrazine-desethyl
Prometon
Atrazine-desisopropyl-^s (SUR)
Atrazine-desisopropyl
Propazine
Atrazine-t/5 (IS#2)
Atrazine
Terbuthylazine
Simazine-t/io (SUR)
Simazine
Prometryn
Ametryn
Simetryn
Cyanazine-t/s (SUR)
Cyanazine
Peak#
Fig. 1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Ret. Time
(minute)
6.44
6.44
6.61
6.62
6.65
6.69
6.71
6.73
6.76
6.84
6.86
6.88
6.90
6.95
7.53
7.64
7.74
8.46
8.49
Quan. Ion
(m/z)
148
145
186
176
172
210
178
173
214
205
200
214
193
201
241
227
213
230
225
1
1
1
(IS#1)
1
2
1
1
2
(IS#2)
2
2
2
2
2
2
2
2
2
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TABLE 4. LOWEST CONCENTRATION MINIMUM REPORTING LEVELS (LCMRL) AND
DETECTION LIMITS (DL)
Analyte
Atrazine-desethyl-desisopropyl
Terbuthylazine-desethyl
Atrazine-desethyl
Prometon
Atrazine-desisopropyl
Propazine
Atrazine
Terbuthylazine
Simazine
Prometryn
Ametryn
Simetryn
Cyanazine
LCMRL Concentration Levels
(HS/L)
0.30, 0.40, 0.60, 0.80, 1.00, 1.20, 1.60
0.40, 0.60, 0.80, 1.00, 1.20, 1.60, 2.00
0.30, 0.40, 0.60, 0.80, 1.00, 1.20, 1.60
0.60, 0.80, 1.00, 1.20, 1.60, 2.00, 3.00
0.40, 0.60, 0.80, 1.00, 1.20, 1.60, 2.00
0.40, 0.60, 0.80, 1.00, 1.20, 1.60, 2.00
0.30, 0.40, 0.60, 0.80, 1.00, 1.20, 1.60
0.40, 0.60, 0.80, 1.00, 1.20, 1.60, 2.00
0.40, 0.60, 0.80, 1.00, 1.20, 1.60, 2.00
0.60, 0.80, 1.00, 1.20, 1.60, 2.00, 3.00
0.60, 0.80, 1.00, 1.20, 1.60, 2.00, 3.00
0.60, 0.80, 1.00, 1.20, 1.60, 2.00, 3.00
0.80, 1.00, 1.20, 1.60, 2.00, 3.00, 4.00
LCMRL
(HS/L)
0.48
0.72
0.60
0.84
0.65
0.68
0.40
0.45
0.60
0.85
0.83
0.78
2.1
DL
(HS/L)
0.13
0.13
0.10
0.54
0.19
0.16
0.12
0.14
0.22
0.24
0.45
0.12
0.69
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TABLE 5. PRECISION AND ACCURACY OF METHOD ANALYTES FORTIFIED AT
3.0 jig/L AND 20 ug/L IN REAGENT WATER (N=7 SAMPLES)
Analyte
Atrazine-desethyl-desisopropyl
Terbuthylazine-desethyl
Atrazine-desethyl
Prometon
Atrazine-desisopropyl
Propazine
Atrazine
Terbuthylazine
Simazine
Prometryn
Ametryn
Simetryn
Cyanazine
Atrazine-desethyl-desisopropyl-13C3
(SUR) - 4 |ig/L
Atrazine-desisopropyl-t/5 (SUR) -
8|ig/L
Simazine-dio (SUR) - 8 |ig/L
Cyanazine-ds (SUR) - 20 |ig/L
Fortified Cone. = 3.0 ug/L
(n=7)
Mean %
Recovery
103
108
105
88.2
103
97.9
97.0
101
95.1
92.1
92.8
88.7
96.8
98.3
102
96.9
92.5
Relative
Standard
Deviation
6.0
5.0
2.7
9.0
3.5
4.7
3.8
5.0
5.5
4.9
4.6
8.5
10
5.5
3.8
3.8
2.8
Fortified Cone. = 20 ug/L
(n=7)
Mean %
Recovery
90.2
89.6
93.9
84.4
93.1
94.3
96.0
96.4
104
89.4
89.6
95.3
94.9
103
100
88.3
81.9
Relative
Standard
Deviation
2.2
3.8
2.0
2.5
2.2
1.4
1.8
1.4
2.2
1.8
1.1
4.7
2.5
3.1
2.9
3.2
2.4
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TABLE 6. PRECISION AND ACCURACY OF METHOD ANALYTES FORTIFIED AT
3.0 jig/L AND 20 ug/L IN A CHLORINATED SURFACE WATER3 (N=7 SAMPLES)
Analyte
Atrazine-desethyl-desisopropyl
Terbuthylazine-desethyl
Atrazine-desethyl
Prometon
Atrazine-desisopropyl
Propazine
Atrazine
Terbuthylazine
Simazine
Prometryn
Ametryn
Simetryn
Cyanazine
Atrazine-desethyl-desisopropyl-
13C3 (SUR) - 4 |ig/L
Atrazine-desisopropyl-Js (SUR)
-8|ig/L
Simazine-t/io (SUR) - 8 |ig/L
Cyanazine-ds (SUR) - 20 |ig/L
Fortified Cone. = 3.0 jig/L
(n=7)
Mean %
Recovery
97.8
97.8
96.1
97.7
102
101
104
97.6
102
97.7
102
95.4
107
100
106
103
107
Relative
Standard
Deviation
1.4
2.5
2.1
5.9
2.0
3.8
4.4
5.6
4.7
5.6
11
4.3
10
2.6
3.6
4.8
3.8
Fortified Cone. = 20 ug/L
(n=7)
Mean %
Recovery
102
98.9
103
97.7
101
98.2
101
100
100
95.5
95.5
98.9
106
107
101
102
97.4
Relative
Standard
Deviation
2.2
6.7
1.4
1.8
1.2
1.1
1.4
1.6
4.3
0.75
1.3
4.1
4.1
4.1
2.0
3.4
4.2
Surface water physical parameters:
organic carbon = 4 mg/L.
pH = 7.3; hardness = 140 mg/L; free chlorine =1.7 mg/L; total
523-36
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TABLE 7. PRECISION AND ACCURACY OF METHOD ANALYTES FORTIFIED AT
1.2 ug/L AND 20 ug/L IN A CHLORINATED GROUNDWATER" (N=7 SAMPLES)
Analyte
Atrazine-desethyl-desisopropyl
Terbuthylazine-desethyl
Atrazine-desethyl
Prometon
Atrazine-desisopropyl
Propazine
Atrazine
Terbuthylazine
Simazine
Prometryn
Ametryn
Simetryn
Cyanazine
Atrazine-desethyl-desisopropyl-
13C3 (SUR) - 4 |ig/L
Atrazine-desisopropyl-t/5 (SUR)
-8|ig/L
Simazine-dio (SUR) - 8 |ig/L
Cyanazine-ds (SUR) - 20 |ig/L
Fortified Cone. = 1.2 ug/L
(n=7)b
Mean %
Recovery
88.9
100
97.6
97.1
100
93.8
100
91.4
110
90.5
92.9
81.9
102
84.6
92.2
103
108
Relative
Standard
Deviation
10
7.1
2.6
7.0
3.8
4.3
9.5
4.1
4.3
12
7.0
6.2
8.2
9.2
5.2
2.3
5.9
Fortified Cone. = 20 ug/L
(n=7)
Mean %
Recovery
92.6
92.6
93.8
90.3
93.8
98.0
100
98.9
98.8
97.1
94.3
95.0
97.9
101
98.7
91.7
85.8
Relative
Standard
Deviation
3.7
3.8
4.2
3.8
3.9
1.4
1.5
1.7
2.5
2.3
2.6
3.1
5.3
3.5
3.4
2.2
4.2
a Ground water physical parameters:
b Atrazine-desethyl-desisopropyl was
hardness = 325 mg/L; free chlorine = 0.5 mg/L.
spiked at 2.0 |ig/L for the low level.
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TABLE 8. SAMPLE HOLDING TIME DATA FOR METHOD ANALYTES FORTIFIED AT
5.0 jig/L IN A CHLORINATED SURFACE WATER* b (N=3 SAMPLES)
Analyte
Atrazine-desethyl-
desisopropyl
Terbuthylazine-
desethyl
Atrazine-desethyl
Prometon
Atrazine-desisopropyl
Propazine
Atrazine
Terbuthylazine
Simazine
Prometryn
Ametryn
Simetryn
Cyanazine
DayO
%R
93.2
101
98.0
93.9
98.7
95.7
96.7
97.1
92.1
94.9
89.6
86.8
98.1
%RSD
4.3
4.4
1.4
5.0
0.4
4.1
1.2
1.7
3.2
5.9
4.7
6.3
4.4
Day 7
%R
95.6
100
99.3
96.1
98.5
100
99.0
97.1
102
103
89.2
99.0
109
%RSD
0.26
3.1
3.2
4.9
1.2
4.8
5.4
5.9
2.7
17
9.2
3.9
4.4
Day 14
%R
97.5
98.4
100
88.5
96.3
97.3
93.2
87.8
100
95.1
83.8
101
96.4
%RSD
5.1
6.6
1.6
7.0
1.7
8.5
5.9
5.2
7.6
5.4
11
2.3
0.80
Day 21
%R
95.5
101
98.3
91.7
101
91.7
91.5
93.6
96.4
94.9
93.0
91.6
100
%RSD
9.1
1.5
1.8
13
2.2
1.5
2.2
8.0
2.9
8.2
1.0
2.1
10
Day 28
%R
95.1
104
95.9
94.1
92.4
90.6
91.3
98.0
88.6
94.4
92.0
89.5
99.0
%RSD
5.8
3.5
4.8
2.1
2.5
2.9
4.6
2.1
6.1
5.7
2.9
3.5
8.3
Surface water physical parameters: pH =
%R = percent recovery; %RSD = percent
7.4; hardness = 140 mg/L; free chlorine = 2.2 mg/L.
relative standard deviation.
523-38
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TABLE 9. EXTRACT HOLDING TIME DATA FOR METHOD ANALYTES FORTIFIED AT
5.0 jig/L IN A CHLORINATED SURFACE WATER" b (N=3 SAMPLES)
Analyte
Atrazine-desethyl-
desisopropyl
Terbuthylazine-desethyl
Atrazine-desethyl
Prometon
Atrazine-desisopropyl
Propazine
Atrazine
Terbuthylazine
Simazine
Prometryn
Ametryn
Simetryn
Cyanazine
Atrazine-desethyl-
desisopropyl-13C3 (SUR)
Atrazine-desisopropyl-t/s
(SUR)
Simazine-6?io (SUR)
Cyanazine-^s (SUR)
DayO
%R
93.2
101
98.0
93.9
98.7
95.7
96.7
97.1
92.1
94.9
89.6
86.8
98.1
100
103
95.9
101
%RSD
4.3
4.4
1.4
5.0
0.40
4.1
1.2
1.7
3.2
5.9
4.7
6.3
4.4
4.1
6.2
0.10
3.6
Day 7
%R
91.9
95.9
100
98.5
97.4
102
100
101
100
102
97.7
98.4
97.7
99.3
103
97.4
97.9
%RSD
3.7
2.3
2.0
0.46
1.2
7.5
2.6
2.2
3.4
0.88
4.6
0.29
0.31
7.5
6.4
1.3
1.7
Day 14
%R
97.6
94.0
99.4
93.1
94.8
96.9
97.1
100
97.6
93.1
97.2
97.8
102
104
107
99.4
103
%RSD
2.6
2.1
3.3
4.5
1.4
2.0
1.8
5.7
3.1
9.5
4.8
0.84
8.4
3.2
2.3
2.1
6.2
Day 21
%R
95.5
95.9
96.0
94.3
101
94.5
95.7
95.8
99.2
104
98.6
94.5
108
96.2
103
100
103
%RSD
2.5
6.4
2.3
6.5
3.0
1.7
1.7
11
1.6
5.0
6.2
1.0
8.4
5.2
5.3
0.37
4.0
Day 28
%R
94.8
102
95.3
93.7
94.2
90.3
93.4
98.8
97.0
100
93.9
94.5
102
100
98.8
97.6
104
%RSD
1.9
2.7
1.9
2.5
1.9
4.2
1.6
5.3
3.1
3.4
10.
6.6
7.2
6.5
0.87
1.8
4.0
Surface water physical parameters: pH = 7.4; hardness = 140 mg/L; free chlorine = 2.2 mg/L.
%R = percent recovery; %RSD = percent relative standard deviation.
523-39
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TABLE 10. INITIAL DEMONSTRATION OF CAPABILITY (IDC) QUALITY CONTROL
REQUIREMENTS
Method
Reference
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
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.
Extract and analyze four to
seven replicate Laboratory
Fortified Blanks (LFBs)
fortified near the midrange
concentration.
Calculate average recovery
for replicates used in Section
9.2.2.
Fortify, extract, and analyze
seven replicate LFBs at the
proposed MRL concentration.
Calculate the mean and the
half range (HR). 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
sample.
Demonstrate that all method analytes
are 50%
Results must be 70-130% of the true
value.
523-40
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TABLE 11. ONGOING QUALITY CONTROL REQUIREMENTS
Method
Reference
Requirement
Specification and Frequency
Acceptance Criteria
Section 8.4
Sample holding time
28 days when processed and
stored according to Sections 8.1
and 8.3.
Sample results are valid only if
samples are analyzed within the
sample holding time.
Section
9.3.1
Laboratory Reagent
Blank (LRB)
One with each Extraction Batch
Demonstrate that all method
analytes are below 1/3 the
Minimum Reporting Level (MRL),
and that possible interference from
reagents and glassware do not
prevent identification and
quantitation of method analytes.
Section
9.3.3
Laboratory Fortified
Blank (LFB)
One with each Extraction Batch
Rotate the fortified
concentrations between low,
medium, and high levels.
Results of LFB analyses at medium
and high fortifications must be 70-
130% of the true value for each
analyte and surrogate. Results of
the low-level LFB must be 50-
150% of the true value.
Section
9.3.5
Internal standard (IS)
Atrazine-c/s and Atrazine-
desethyl-Jy are added to all
standards and sample extracts.
Peak area counts for all ISs in field
and QC sample extracts must be
within ±50% of the average peak
area calculated during the initial
calibration and ±30% from the most
recent continuing calibration check
(CCC). If ISs do not meet these
criteria, corresponding method
results are invalid.
Section
9.3.6
Surrogates
Surrogates are added to all field
and QC samples prior to
extraction.
70-130% recovery
Section
9.3.7
Laboratory Fortified
Sample Matrix
(LFSM)
One LFSM per Extraction
Batch. Fortify the LFSM with
method analytes at a
concentration close to but
greater than the native
concentrations (if known).
For LFSMs fortified at
concentrations <2 x MRL, the result
must be within 50-150% of the true
value. All other LFSMs must be
within 70-130% of the true value.
Section
9.3.8
Laboratory Fortified
Sample Matrix
Duplicate (LFSMD)
or
Field Duplicate (FD)
One LFSMD or FD with each
Extraction Batch
For LFSMDs or FDs, RPDs must
be <30% at middle and high levels
of fortification and <50% at
concentrations <2 x the MRL.
Section
9.3.9
Quality Control
Sample (QCS)
Analyze mid-level QCS sample
when new stock standard
solutions are prepared and at
least quarterly if stock
standards are prepared less
frequently.
Results must be 70-130% of the
true value.
523-41
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Method
Reference
Requirement
Specification and Frequency
Acceptance Criteria
Section
10.2
Initial calibration
Use the internal standard
calibration technique to
generate a linear or quadratic
calibration curve. Use at least 5
standard concentrations.
Validate the calibration curve
as described in Section 10.2.5.
When each calibration standard is
calculated as an unknown using the
calibration curve, the lowest level
standard must be within 50-150%
of the true value. All other points
must be within 70-130% of the true
value.
Section
10.3
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 50-150% of the true value.
All other points must be within 70-
130% of the true value.
Results for field samples that are
not bracketed by acceptable CCCs
are invalid.
523-42
-------
12 14
3,4 5
15 16 17
19
6.66667
8
Figure 1. Example chromatogram recorded on the GC/TOF-MS for a chlorinated groundwater fortified with Method 523
analytes at 5 (J,g/L. Numbered peaks are identified in Table 3.
523-43
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