United States
Environmental Protection
\r ^1 M^k. Agency
www.epa.gov August 1993
Method 645: The Determination of
Certain Amine Pesticides and
Lethane in Municipal and
Industrial Wastewater
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Method 645
The Determination of Certain
Amine Pesticides and Lethane in
Municipal and Industrial
Wastewater
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Method 645
The Determination of Certain Amine Pesticides and Lethane in
Municipal and Industrial Wastewater
1. Scope and Application
1.1 This method covers the determination of certain amine pesticides and lethane in
municipal and industrial wastewater. The following parameters may be determined by
this method.
1.2 The estimated detection limit (EDL) for each parameter is listed in Tables 1 and 2. The
EDL was calculated from the minimum detectable response of the nitrogen/phosphorous
detector equal to 5 times the gas chromatographic (GC) background noise assuming a 10-
mL final extract volume of a 1-L reagent water sample and a GC injection of 5 |iL. The
EDL for a specific wastewater may be different depending on the nature of interferences
in the sample matrix.
1.3 This is a gas chromatographic (GC) method applicable to the determination of the
compounds listed above in municipal and industrial discharges. When this method is
used to analyze unfamiliar samples for any or all of the compounds listed above,
compound identifications should be supported by at least one additional qualitative
technique. Section 13 provides gas chromatograph/mass spectrometer (GC/MS)
conditions appropriate for the qualitative confirmation of compound identifications.
1.4 This method is restricted to use by or under the supervision of analysts experienced in
the operation of gas chromatographs and in the interpretation of chromatograms.
2. Summary of Method
2.1 The amine pesticides and lethane are removed from the sample matrix by extraction with
methylene chloride. The extract is dried, exchanged into hexane, and analyzed by gas
chromatography. Column chromatography is used as necessary to eliminate interferences
which may be encountered. Measurement of the pesticides is accomplished with a
nitrogen/phosphorous specific detector.
2.2 Confirmatory analysis by gas chromatography/mass spectrometry is recommended
(Section 13) when a new or undefined sample type is being analyzed if the concentration
is adequate for such determination.
Parameter
Alachlor
Butachlor
Diphenamid
Fluridone
Lethane
Norflurazon
112-56-1
27314-13-2
15972-60-8
23184-66-9
957-51-7
59756-60-4
CAS No.
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Method 645
3. Interferences
3.1 Solvent, reagents, glassware, and other sample-processing hardware may yield discrete
artifacts and/or elevated baselines causing misinterpretation of gas chromatograms. All
of these materials must be demonstrated to be free from interferences under the
conditions of the analysis by running laboratory reagent blanks as described in Section
9.1
3.1.1 The use of high-purity reagents and solvents helps to minimize interference
problems. Purification of solvents by distillation in all-glass systems may be
required.
3.1.2 Glassware must be scrupulously cleaned.1 Clean all glassware as soon as possible
after use by rinsing with the last solvent used in it. This should be followed by
detergent washing with hot water and rinses with tap water and reagent water.
It should then be drained dry and heated in a muffle furnace at 400°C for 15 to
30 minutes. Solvent rinses with acetone and pesticide-quality hexane may be
substituted for the muffle furnace heating. Volumetric ware should not be heated
in a muffle furnace. After drying and cooling, glassware should be sealed and
stored in a clean environment to prevent any accumulation of dust or other
contaminants. Store the glassware inverted or capped with aluminum foil.
3.2 Interferences co-extracted from the samples will vary considerably from source to source,
depending on the diversity of the industrial complex or municipality being sampled.
While general cleanup procedures are provided as part of this method, unique samples
may require additional cleanup approaches to achieve the detection limits listed in Tables
1 and 2.
4. Safety
4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely
defined; however, each chemical compound should be treated as a potential health
hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest
possible level by whatever means available. The laboratory is responsible for maintaining
a current awareness file of OSHA regulations regarding the safe handling of the
chemicals specified in this method. A reference file of material data handling sheets
should also be made available to all personnel involved in the chemical analysis.
Additional references to laboratory safety are available and have been identified2 4 for the
information of the analyst.
5. Apparatus and Equipment
5.1 Sample containers: Narrow-mouth glass bottles, 1-L or 1-quart volume, equipped with
polytetrafluoroethylene (PTFE)-lined screw-caps. Wide-mouth glass bottles, 1-quart
volume, equipped with PTFE-lined screw-caps may also be used. Prior to use, wash
bottles and cap liners with detergent and rinse with tap and distilled water. Allow the
bottles and cap liners to air dry, then muffle at 400°C for 1 hour. After cooling, rinse the
bottles and cap liners with hexane, seal the bottles, and store in a dust-free environment.
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Method 645
5.1.1 Automatic sampler (optional): Must incorporate glass sample containers for the
collection of a minimum of 250 mL. Sample containers must be kept refrigerated
at 4°C and protected from light during compositing. If the sampler uses a
peristaltic pump, a minimum length of compressible silicone rubber tubing may
be used. Before use, however, the compressible tubing should be thoroughly
rinsed with methanol, followed by repeated rinsings with reagent water to
minimize the potential for contamination of the sample. An integrating flow
meter is required to collect flow-proportional composites.
5.2 Kuderna-Danish (K-D) glassware.
5.2.1 Synder column: Three-ball macro (Kontes K-503000-0121 or equivalent).
5.2.2 Concentrator tube: 10-mL, graduated (Kontes K-570050-1025 or equivalent) with
ground-glass stopper.
5.2.3 Evaporative flask: 500-mL (Kontes K-570001-0500 or equivalent). Attach to
concentrator tube with springs.
5.3 Gas chromatography system.
5.3.1 The gas chromatograph must be equipped with a glass-lined injection port
compatible with the detector to be used. A data system is recommended for
measuring peak areas.
5.3.1.1 Column 1: 180 cm long by 2 mm ID, glass, packed with 10% OV-11 on
Gas Chrom W-HP (100/120 mesh) or equivalent.
5.3.1.2 Column 2: 180 cm long by 2 mm ID, PyrexR glass, packed with 3% Dexsil
300 on Chromasorb W-HP (80/100 mesh) or equivalent.
5.3.1.3 Column 3: 180 cm long by 2mm ID Glass, packed with 3% SP-2100 on
Supelcoport (100/120 mesh) or equivalent.
5.3.1.4 Column 1 was used to develop the accuracy and precision statements in
Section 12. Guidelines for the use of alternative column packings are
provided in Section 10.3.1.
5.3.1.5 Detector: Nitrogen/phosphorous. This detector has proven effective in
the analysis of wastewaters for the parameters listed in Section 1.1 and
was used to develop the method performance statements in Section 12.
Guidelines for the use of alternate detectors are provided in Section 10.3.
5.4 Chromatographic column: 300 mm long by 10 mm ID Chromaflex, equipped with
coarse-fritted bottom plate and PTFE stopcock. (Kontes K-420540-0213 or equivalent).
5.5 Drying column: Approximately 400 mm long by 20 mm ID borosilicate glass, equipped
with coarse-fritted bottom plate.
5.6 Miscellaneous.
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Method 645
5.6.1 Balance: Analytical, capable of accurately weighing to the nearest 0.0001 g.
5.6.2 Separatory funnel: 2-L, equipped with PTFE stopcock.
5.6.3 Water bath: Heated with concentric ring cover, capable of temperature control
(±2°C). The bath should be used in a hood.
5.6.4 Standard solution storage containers: 15-L bottles with PTFE-lined screw-caps.
5.6.5 Boiling chips: Approximately 10/40 mesh. Heat to 400°C for 30 minutes or
perform a Soxhlet extraction with methylene chloride.
6. Reagents and Consumable Materials
6.1 Reagents.
6.1.1 Acetone, hexane, and methylene chloride: demonstrated to be free of analytes.
6.1.2 Florisil: PR grade (60/100 mesh). Purchase activated at 675°C and store in glass
containers with glass stoppers or foil-lined screw-caps. Before use, activate each
batch overnight at 200°C in foil-covered glass containers. To prepare for use,
place the amount necessary for the number of columns to be run in a 500-mL
reagent bottle and add 2% by weight of reagent water. Seal and mix thoroughly
by shaking or rolling for 10 minutes. Allow to stand for at least 2 hours prior to
use. The mixture must be homogeneous. Keep the bottle tightly sealed to ensure
proper activity.
6.1.3 Reagent water: reagent water is defined as a water in which an interferent is not
observed at the method detection limit of each parameter of interest.
6.1.4 Sodium hydroxide (NaOH) solution (10N): Dissolve 40 g NaOH in reagent water
and dilute to 100 mL.
6.1.5 Sodium sulfate: Granular, anhydrous. Condition by heating at 400°C for 4 hours
in a shallow tray.
6.1.6 Sulfuric acid (H2S04) solution (1 + 1): Add a measured volume of concentrated
H2S04 to an equal volume of reagent water.
6.1.7 Sodium thiosulfate: ACS, granular.
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Method 645
6.2 Standard stock solutions (1.00 |ig/|_iL): These solutions may be purchased as certified
solutions or prepared from pure standard materials using the following procedures.
6.2.1 Prepare standard stock solutions by accurately weighing about 0.0100 g of pure
material. Dissolve the material in hexane or other suitable solvent and dilute to
volume in a 10-mL volumetric flask. Larger volumes can be used at the
convenience of the analyst. If compound purity is certified at 96% or greater, the
weight can be used without correction to calculate the concentration of the
standard stock.
6.2.2 Store standard stock solutions at 4°C in 15-mL bottles equipped with PTFE-lined
screw-caps. Standard stock solutions should be checked frequently for signs of
degradation or evaporation, especially just prior to preparing calibration
standards from them.
6.2.3 Standard stock solutions must be replaced after 6 months, or sooner if comparison
with check standards indicates a problem.
7. Sample Collection, Preservation, and Storage
7.1 Collect all samples in duplicate. Grab samples must be collected in glass containers.
Conventional sampling practices5 should be followed, except that the bottle must not be
prewashed with sample before collection.
7.2 The samples must be iced or refrigerated at 4°C from the time of collection until
extraction.
7.3 Chemical preservatives should not be used in the field unless more than 24 hours will
elapse before delivery to the laboratory. If the samples will not be extracted within
48 hours of collection, the sample should be adjusted to a pH range of 6.0 to 8.0 with
sodium hydroxide or sulfuric acid.
7.4 All samples must be extracted within 7 days and completely analyzed within 40 days of
extraction6.
8. Calibration and Standardization
8.1 Calibration.
8.1.1 A set of at least three calibration solutions containing the method analytes is
needed. One calibration solution should contain each analyte at a concentration
approaching but greater than the estimated detection limit (Tables 1 and 2) for
that compound; the other two solutions should contain analytes at concentrations
that bracket the range expected in samples. For example, if the detection limit for
a particular analyte is 0.2 (Jg/L, and a sample expected to contain approximately
5 Hg/L is analyzed, solutions of standards should be prepared at concentrations
representing 0.3 Hg/L, 5|ig/L, and 10 Hg/L for the particular analyte.
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Method 645
8.1.2 To prepare a calibration solution, add an appropriate volume of a standard stock
solution to a volumetric flask and dilute to volume with hexane.
8.1.3 Starting with the standard of lowest concentration, analyze each calibration
standard according to Section 10.3 and tabulate peak height or area response
versus the mass of analyte injected. The results can be used to prepare a
calibration curve for each compound. Alternatively, if the ratio of response to
concentration (calibration factor) is a constant over the working range (<10%
relative standard deviation), linearity through the origin can be assumed and the
average ratio or calibration factor can be used in place of a calibration curve.
8.1.4 The working calibration curve or calibration factor must be verified on each
working day by the measurement of one or more calibration standards. If the
response for any analyte varies from the predicted response by more than ±10%,
the test must be repeated using a fresh calibration standard. If the results still do
not agree, generate a new calibration curve.
9. Quality Control
9.1 Monitoring for interferences.
9.1.1 Analyze a laboratory reagent blank each time a set of samples is extracted. A
laboratory reagent blank is a 1-L aliquot of reagent water. If the reagent blank
contains a reportable level of any analyte, immediately check the entire analytical
system to locate and correct for possible interferences and repeat the test.
9.2 Assessing accuracy.
9.2.1 After every 10 samples, and preferably in the middle of each day, analyze a
laboratory control standard. Calibration standards may not be used for accuracy
assessments and the laboratory control standard may not be used for calibration
of the analytical system.
9.2.1.1 Laboratory control standard concentrate: From stock standards prepared
as described in Section 6.3, prepare a laboratory control standard
concentrate that contains each analyte of interest at a concentration of
2 \ig/mL in acetone or other suitable solvent.
9.2.1.2 Laboratory control standard: Using a pipette, add 1.00 mL of the
laboratory control standard concentrate to a 1-L aliquot of reagent water.
9.2.1.3 Analyze the laboratory control standard as described in Section 10. For
each analyte in the laboratory control standard, calculate the percent
recovery (P;) with the equation:
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Method 645
Equation 1
100 S,
P, = 1
where
St = Analytical results from the laboratory control standard, in jig/L
Ti = Known concentration of the spike, in jig/L
9.2.2 At least annually, the laboratory should participate in formal performance
evaluation studies, where solutions of unknown concentrations are analyzed and
the performance of all participants is compared.
9.3 Assessing precision
9.3.1 Precision assessments for this method are based upon the analysis of field
duplicates (Section 7.1). Analyze both sample bottles for at least 10% of all
samples. To the extent practical, the samples for duplication should contain
reportable levels of most of the analytes.
9.3.2 For each analyte in each duplicate pair, calculate the relative range7 (RR,) with the
equation:
Equation 2
100i?;
PR:
X
where
Rt = Absolute difference between the duplicate measurements % and g , in jig/L
X\ = Average concentration found
^ +*a
, in jig/L
9.3.3 Individual relative range measurements are pooled to determine average relative
range or to develop an expression of relative range as a function of concentration.
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Method 645
10. Procedure
10.1 Sample extraction.
10.1.1 Mark the water meniscus on the side of the sample bottle for later determination
of sample volume. Pour the entire sample into a 2-L separatory funnel. Check
the pH of the sample with wide-range pH paper and adjust to within the range
of 5 to 9 with sodium hydroxide or sulfuric acid.
10.1.2 Add 60 mL of methylene chloride to the sample bottle and shake for 30 seconds
to rinse the walls. Transfer the solvent to the separatory funnel and extract the
sample by shaking the funnel for 2 minutes with periodic venting to release vapor
pressure. Allow the organic layer to separate from the water phase for a
minimum of 10 minutes. If the emulsion interface between layers is more than
one-third the volume of the solvent layer, the analyst must employ mechanical
techniques to complete the phase separation. The optimum technique depends
on the sample, but may include stirring, filtration of the emulsion through glass
wool, or centrifugation. Collect the extract in a 250-mL Erlenmeyer flask.
10.1.3 Add an additional 60-mL volume of methylene chloride to the sample bottle and
complete the extraction procedure a second time, combining the extracts in the
Erlenmeyer flask.
10.1.4 Perform a third extraction in the same manner. Pour the combined extract
through a drying column containing about 10 cm of anhydrous sodium sulfate,
and collect it in a 500-mL K-D flask equipped with a 10-mL concentrator tube.
Rinse the Erlenmeyer flask and column with 20 to 30 mL of methylene chloride
to complete the quantitative transfer.
10.1.5 Add one or two clean boiling chips to the flask and attach a three-ball Snyder
column. Prewet the Snyder column by adding about 1 mL of methylene chloride
to the top. Place the K-D apparatus on a hot water bath (80 to 85°C) so that the
concentrator tube is partially immersed in the hot water and the entire lower
rounded surface of the flask is bathed in steam. Adjust the vertical position of
the apparatus and the water temperature as required to complete the
concentration in 15 to 20 minutes. At the proper rate of distillation, the balls of
the column will actively chatter but the chambers will not flood. When the
apparent volume of liquid reaches 1 mL, remove the K-D apparatus and allow it
to drain and cool for at least 10 minutes. Remove the Snyder column and rinse
the flask and its lower joint into the concentrator tube with 1 to 2 mL of
methylene chloride.
10.1.6 For Florisil column cleanup or gas chromatography, the extract must be in hexane
solution. To exchange the solvent to hexane, add one or two fresh boiling chips
to the flask and ampule containing the extract, add 50 mL of hexane, and reattach
the Snyder column. Pour about 1 mL of hexane into the top of the Snyder
column, and concentrate the extract at 85 to 95°C in the hot water bath as above.
When the apparent volume of liquid reaches 1 mL, remove the K-D apparatus
from the water bath and allow it to drain and cool for at least 10 minutes.
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Method 645
10.1.7 Remove the Snyder column, rinse the flask and its lower joint into the
concentrator tube with 1 to 2 mL of hexane. A 5-mL syringe is recommended for
this operation. Dilute to 10 mL with hexane for analysis by gas chromatography
(Section 10.3) if cleanup is not required. If the extract requires cleanup, proceed
to Section 10.2. If the extracts will be stored longer than 2 days, they should be
transferred to PTFE-sealed screw-cap bottles. Proceed with gas chromatographic
analysis.
10.1.8 Determine the original sample volume by refilling the sample bottle to the mark
and transferring the liquid to a 1000-mL graduated cylinder. Record the sample
volume to the nearest 5 mL.
10.2 Cleanup and separation.
10.2.1 Cleanup procedures may not be necessary for a relatively clean sample matrix.
The cleanup procedures recommended in this method have been used for the
analysis of alachlor, butachlor, diphenamid, and lethane in various clean waters
and municipal effluents. The use of Florisil as the cleanup material for fluridone
and norflurazon has been demonstrated to yield recoveries of less than 50%, and
is not recommended as a cleanup material for these compounds. Use of specific
detectors may obviate the necessity for cleanup of relatively clean sample
matrices. If particular circumstances demand the use of an alternative cleanup
procedure, the analyst must determine the elution profile and demonstrate that
the recovery of each compound of interest is no less than 85%.
10.2.2 Place the necessary amount of deactivated Florisil into a 20 mm ID
chromatographic column and tap the column to settle the Florisil. Add 1 to 2 cm
of anhydrous sodium sulfate to the top of the Florisil.
10.2.3 Pre-elute the column with 50 to 60 mL of hexane. Discard the eluate and, just
prior to exposure of the sodium sulfate layer to the air, transfer the sample extract
onto the column by decantation. Complete the transfer by rinsing with two
additional 2-mL volumes of hexane. Alternatively, a measured aliquot of the
extract may be taken for cleanup.
10.2.4 Just prior to exposure of the sodium sulfate layer to the air, elute the column with
100 mL hexane. Discard the eluate and repeat the elution with 200 mL of 6%
(v/v) acetone in hexane. Collect the eluate in a 500-mL K-D flask equipped with
a 10-mL concentrator tube (Fraction 1). All elutions should be carried out using
a flow rate of about 5 mL/min.
10.2.5 Perform a second elution with 200 mL of 15% acetone in hexane (Fraction 2).
Collect each fraction in a separate K-D apparatus. The elution pattern for these
compounds is shown in Table 3.
10.2.6 Determine, from Table 3, the fractions of interest and concentrate by standard K-D
technique, as indicated in Section 10.1.5, using hexane in place of methylene
chloride, to a volume of 10 mL.
10.2.7 Analyze the fractions by gas chromatography.
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Method 645
10.3 Gas chromatography analysis.
10.3.1 Recommended columns and detectors and operating conditions for the gas
chromatography system are described in Section 5.3. Tables 1 and 2 summarize
the recommended operating conditions for the gas chromatograph. Included in
these tables are retention times and estimated detection limits that can be
achieved by this method. Examples of the separations achieved are shown in
Figures 1 through 3. Other packed columns, chromatographic conditions, or
detectors may be used if data quality comparable to Table 4 is achieved.
Capillary (open-tubular) columns may also be used if the relative standard
deviations of responses for replicate injections are demonstrated to be less than
6% and data quality comparable to Table 4 is achieved.
10.3.2 Inject 2 to 5 |iL of the sample extract using the solvent-flush technique.8 Record
the volume injected to the nearest 0.05 |iL, the total extract volume, and the
resulting peak size in area or peak height units.
10.3.3 The width of the retention-time window used to make identifications should be
based upon measurements of actual retention-time variations of standards over
the course of the day. Three times the standard deviation of a retention time for
a compound can be used to calculate a suggested window size; however, the
experience of the analyst should weigh heavily in the interpretation of
chromatograms.
10.3.4 If the response for the peak exceeds the working range of the system, dilute the
extract and reanalyze.
10.3.5 If the measurement of the peak response is prevented by the presence of
interferences, further cleanup is required.
11. Calculations
11.1 Determine the concentration (C) of individual compounds in the sample in micrograms
per liter with the equation:
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Method 645
Equation 3
Concentration, \yg!L =
where
A = Amount of analytes injected, in ng
Vt = Volume of extract injected, in {iL
Vt = Volume of total extract, in p.g/L
V, = Volume of water extracted, in mL
(A) (V)
(V) (K)
11.2 Report the results for the unknown samples in micrograms per liter. Round off the
results to the nearest 0.1 Hg/L or two significant figures.
12. Method Performance
12.1 Estimated detection limits (EDL) and associated chromatographic conditions are listed
in Table l.9 The detection limits were calculated from the minimum detectable response
of the EC detector equal to 5 times the GC background noise, assuming a 10-mL final
extract volume of a 1-L sample and a GC injection of 5 |iL.
12.2 Single-laboratory accuracy and precision studies were conducted by Environmental
Science and Engineering,6 using spiked samples. The results of these studies are
presented in Table 2.
13. GC/MS Confirmation
13.1 It is recommended that GC/MS techniques be judiciously employed to support
qualitative identifications made with this method. The mass spectrometer should be
capable of scanning the mass range from 35 amu to a mass 50 amu above the molecular
weight of the compounds of interest. The instrument must be capable of scanning the
mass range at a rate to produce at least 5 scans per peak, but not to exceed 7 scans per
peak utilizing a 70 V (nominal) electron energy in the electron impact ionization mode.
A GC-to-MS interface constructed of all glass or glass-lined materials is recommended.
A computer system should be interfaced to the mass spectrometer that allows the
continuous acquisition and storage on machine-readable media of all mass spectra
obtained throughout the duration of the chromatographic program.
13.2 Gas chromatographic columns and conditions should be selected for optimum separation
and performance. The conditions selected must be compatible with standard GC/MS
operating practices. Chromatographic tailing factors of less than 5.0 must be achieved.
The calculation of tailing factors is illustrated in Method 625.10
13.3 At the beginning of each day that confirmatory analyses are to be performed, the GC/MS
system must be checked to see that all DFTPP performance criteria are achieved.11
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Method 645
13.4 To confirm an identification of a compound, the background-corrected mass spectrum
of the compound must be obtained from the sample extract and compared with a mass
spectrum from a stock or calibration standard analyzed under the same chromatographic
conditions. It is recommended that at least 25 ng of material be injected into the GC/MS.
The criteria below must be met for qualitative confirmation.
13.4.1 The molecular ion and other ions that are present above 10% relative abundance
in the mass spectrum of the standard must be present in the mass spectrum of the
sample with agreement to ±10%. For example, if the relative abundance of an ion
is 30% in the mass spectrum of the standard, the allowable limits for the relative
abundance of that ion in the mass spectrum for the sample would be 20 to 40%.
13.4.2 The retention time of the compound in the sample must be within 6 seconds of
the same compound in the standard solution.
13.4.3 Compounds that have similar mass spectra can be explicitly identified by GC/MS
only on the basis of retention time data.
13.5 Where available, chemical ionization mass spectra may be employed to aid in the
qualitative identification process.
13.6 Should these MS procedures fail to provide satisfactory results, additional steps may be
taken before reanalysis. These may include the use of alternative packed or capillary GC
columns or additional cleanup.
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Method 645
References
1. ASTM Annual Book of Standards, Part 31, D3694, "Standard Practice for Preparation of
Sample Containers and for Preservation," American Society for Testing and Materials,
Philadelphia, Pennsylvania, p. 679, 1980.
2. "Carcinogens—Working with Carcinogens," Department of Health, Education, and
Welfare, Public Health Service, Center for Disease Control, National Institute for
Occupational Safety and Health, Publication No. 77-206, August 1977.
3. "OSHA Safety and Health Standards, General Industry" (29 CFR 1910), Occupational
Safety and Health Administration, OSHA 2206 (Revised, January 1976).
4. "Safety in Academic Chemistry Laboratories," American Chemical Society Publication,
Committee on Chemical Safety, 3rd Edition, 1979.
5. ASTM Annual Book of Standards, Part 31, D3370, "Standard Practice for Sampling
Water," American Society for Testing and Materials, Philadelphia, Pennsylvania, p. 76,
1980.
6. Test procedures for Pesticides in Wastewaters, EPA Contract Report #68-03-2897.
Unpublished report available from U.S. Environmental Protection Agency, Environmental
Monitoring and Support Laboratory, Cincinnati, Ohio.
7. "Handbook for Analytical Quality Control in Water and Wastewater Laboratories,"
EPA-600/4-79-019, U.S. Environmental Protection Agency, Environmental Monitoring and
Support Laboratory - Cincinnati, Ohio, March 1979.
8. Burke, J.A. "Gas Chromatography for Pesticide Residue Analysis; Some Practical
Aspects," Journal of the Association of Official Analytical Chemists, 48, 1037 (1965).
9. "Evaluation of Ten Pesticide Methods," U.S. Environmental Protection Agency, Contract
No. 68-03-1760, Task No. 11, U.S. Environmental Monitoring and Support Laboratory,
Cincinnati, Ohio (in preparation).
10. "Methods for Organic Chemical Analysis of Municipal and Industrial Wastewater"
EPA-600/4-82-057, U.S. Environmental Protection Agency, Environmental Monitoring and
Support Laboratory - Cincinnati, Ohio.
11. Eichelberger, J.W., Harris, L.E., and Budde, W.L. Analytical Chemistry, 46, 1912 (1975).
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Method 645
Table 1. Gas Chromatography and Detection Limits of Certain Amines and Lethane
Estimated
Retention Time (mm) Detection Limit
Parameter Column 1 | Column 2 | Column 3 (\ig/L)
Alachlor 6.9 — — 0.2
Butachlor 10.5 — — 0.3
Diphenamide 10.8 — — 0.2
Fluridone 2.2 2.45 2.1 0.5
Lethane 2.0 — — 0.1
Norflurazon 18.4 — — 0.02
Column 1: Glass, 180 cm long by 2 mm ID, packed with 10% OV-11 on Gas Chrom W-HP,
100/120 mesh; nitrogen carrier gas at a flow rate of 30 mL/min. Column temperature is held
at 225°C for 4 minutes after injection and then programmed to 275°C at 4°/min and held for
8 minutes.
Column 2: Glass, 180 cm long by 2 mm ID, packed with 3% Dexsil 300 on Chromasorb W-HP,
80/100 mesh; nitrogen carrier gas at a flow rate of 30 mL/min. Column temperature at 300°C
isothermal.
Column 3: Glass, 180 cm long by 2 mm ID, packed with 3% SP-2100 on Supelcoport, 100/120
mesh; nitrogen carrier gas at a flow rate of 40 mL/min. Column temperature at 275°C
isothermal.
Table 2. Single-Laboratory Accuracy and Precision
Average
Relative
Spike Range
No. of
Percent
Standard
Parameter
Matrix Type*
(Vg/L)
Replicates
Recovery
Deviation (%/
Alachlorn
1
255
7
113
9.0
1
996
7
104
13.3
Butachlor
1
286
7
93.1
8.2
1
1,420
7
92.8
4.3
Diphenamid
2
9.3
7
100
14.2
3
740
7
98.8
7.0
Fluridone**
1
20.8
7
92.0
11.5
1
998
7
88.4
11.4
Lethane
1
167
7
93.3
19.9
1
576
7
97.6
29.4
Norlurazone**
1
243
7
89.5
7.4
3
1,048
7
102
6.1
1 = Manufacturing effluent wastewaters.
2 = Manufacturing effluent wastewater + POTW effluent at a ratio of 1:200.
3 = Manufacturing effluent wastewater + POTW effluent at a ration of 1:1.
Florisil cleanup not employed.
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Method 645
Table 3. Florisil* Cleanup Recoveries
Solvent Average Percent Recoveries Lethane
Fraction** Alachlor Butachlor Diphenamid
1 103 95 106
2 ND ND 96 ND
2% deactivated.
1 = 6% acetone/hexane
2 = 15% acetone/hexane
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Method 645
Lethane (2.0)
Butachlor (10.5)
Alachlor (6.9)
DiphenamkJ(10.8)
Norflurazon (18.4)
Figure 1.
*Retention Time in parentheses
Gas Chromatogram of Amines/Lethane (Column 2)
AS2-002-73A
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Method 645
Fluridone
0 5
Retention Time (minutes)
A52-002-74A
Figure 2. Gas Chromatogram of Fluridone (Column 2)
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Method 645
Fluridone
0
2.0
4.0
Retention Time (minutes)
A62-002-75A
Figure 3. Gas Chromatogram of Fluridone (Column 3)
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