P882-156 076
THE DETERMINATION OF ORGANONITROGEN
PESTICIDES IN INDUSTRIAL
AND MUNICIPAL WASTBiATER
Method 633
Thomas A. Pressley
and
James E. Longbottom
Physical and Chemical Methods Branch
Environmental Monitoring and Support Laboratory
Cincinnati, Ohio 45268
January 1982
ENVIRONMENTAL MONITORING AND SUPPORT LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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THE DETERMINATION OF ORGANONITROGEN PESTICIDES
IN INDUSTRIAL AND MUNICIPAL WASTEWATER
METHOD 633
1. Scope and Application
1.1 This method covers the determination of certain organonitrogen
pesticides. The following parameters can be determined by this
method:
Parameter STORET No. - CAS No.
Bromacil ' — 314-40-9
Deet ~ 134-62-3
Hexazlnone — 51235-04-2
Metrfbuzin 81408 21087-64-9
Terbacil — 5902-51-2
THadiraefon — 43121-43-3
Tricyclazole — 41814-78-2
1.2 This 1s a gas chromatographlc (GO) method applicable to the deter-
mination of the compounds listed above in industrial and municipal
discharges as provided under 40 CFR 136.1. Any modification of
this method beyond those expressly permitted, shall be considered a
major modification subject to application and approval of alternate
test procedures under 40 CFR 136.4 and 136.5.
1.3 The method detection limit (MDL, defined 1n Section 15) for five of
the parameters are listed in Table 1. The MDL for a specific
wastewater may differ from those listed, depending upon the nature
of Interferences in the sample matrix.
1.4 This method 1s restricted to use by or under the supervision of
analysts experienced 1n the use of gas chromatography and in the
interpretation of gas chromatograns. Each analyst must demonstrate
the ability to generate acceptable results with this method using
the procedure described 1n Section 8.2.
1.5 When this method 1s used to analyze unfamiliar samples for any or
all of the compounds above, compound identifications should be
supported by at least one additional qualitative technique.
Section 14 provides gas chromatograph/mass spectrometer (GC/MS)
criteria appropriate for the qualitative confirmation of compound
Identifications.
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2. Summary of Method
2.1 A measured volume of sample, approximately 1-Hter, is solvent
extracted with methylene chloride using a separatory funnel. The
raethylene chloride extract 1s dried and exchanged to acetone during
concentration to a volume of 10 ml or less. Gas chrcmatographic
conditions are described which permit the separation and measure-
ment of the compounds in the extract by gas chromatography with a
thermionic bead detector.'
3. Interferences
3.1 Method Interferences may be caused by contaminants in solvents,
reagents,.glassware and other sample processing apparatus that lead
to discrete artifacts or elevated baselines in gas chroraatograms.
All reagents and apparatus must be routinely demonstrated to be
free from interferences under the conditions of the analysis by
running laboratory reagent blanks as described in Section 8.5.
3.1.1 Glassware must be scrupulously cleaned.2 Clean all
glassware as soon as possible after use by thoroughly
rinsing with the last solvent used in it. Follow by washing
with hot water and detergent and thorough rinsing with tap
and reagent water. Drain dry, and heat 1n an oven or muffle
furnace at 400°C for 15 to 30 m1n. Do not heat volumetric
ware. Thermally stable materials such as PCBs, might not be
eliminated by this treatment. Thorough rinsing with acetone
and pesticide quality hexane may be substituted for the
heating. After drying and cooling, seal and store glassware
In a clean environment to prevent any accumulation of dust
or other contaminants. Store Inverted or capped with
aluminum foil.
3.1.2 The use of high purity reagents and solvents helps to mini-
mize Interference problems. Purification of solvents by
distillation 1n all-glass systems may be required.
3.2 Matrix Interferences may be caused by contaminants that are coex-
tracted from the sample. The extent of matrix interferences will
vary considerably from source to source, depending upon the nature
and diversity of the Industrial complex or municipality sampled.
Unique samples may require special cleanup, approaches to achieve
the MOL listed 1n Table 1*
4.1 The toxicity or cardnogenlcity of each reagent used in this method
has not been precisely defined; however, each chemical compound
must 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 1s responsible
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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 identified 3-5 for the information of the analyst.
5. Apparatus and Materials
5.1 Sampling equipment, for discrete or composite sampling.
5.1.1 Grab sample bottle - Amber borosilicate or flint glass,
T-liter or 1-quart volume, fitted with screw caps lined with
TFE-fluorocarbon. Aluminum foil may be substituted for TFE
if the sample is not corrosive. If amber bottles are not
available, protect samples from light. The container and cap
liner must be washed, rinsed with acetone or methylene
chloride, and dried before use to minimize contamination.
5.1.2 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 must 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 Glassware (All specifications are suggested. Catalog numbers are
Included for Illustration only.)
5.2.1 Separatory funnel - 2000-mL, with TFE-fluorocarbon stopcock,
ground glass or TFE stopper.
5.2.2 Drying column - Chromatographic column 400 irni long x 19 ran
ID with coarse fritted disc.
5.2.3 Concentrator tube, Kuderna-Oanish - 10-mL, graduated (Kontes
K-570050-1025 or equivalent). Calibration must be checked
at the volumes employed in the test. Ground glass stopper
1s used to prevent evaporation of extracts.
5.2.4 Evaporative flask, Kudema-Oanish - 500-mL (Kontes
• K-570001-0500 or equivalent). Attach to concentrator tube
with springs.
5.2.5 Snyder column, Kuderna-Oanish - three-ball macro (Kontes
K-503000-0121 or equivalent).
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5.2.6 Vials - Amber glass, 10 to 15 at capacity with
TFE-fluorocarbon lined screw cap.
5.3 Boiling chips - approximately 10/40 mesh. • Heat at 400°C for 30
m1n or Soxhlet extract with methylene chloride.
5.4 Water bath - Heated, with concentric ring cover, capable of temper-
ature control (± 2°C). The bath should be used 1n a hood.
5.5 Balance - Analytical, capable of accurately weighing to the nearest
0.0001 g.
5.6- Sas chroraatograph - Analytical system complete with gas chromato-
graph suitable for on-column Injection and all required accessories
Including syringes, analytical columns, gases, detector and strip-
chart recorder. A data system 1s recommended for measuring peak
areas.
5.6.1 Column 1 - 180 cm long x 2 mm ID glass, packed with 3<
SP-22500B on Supelcoport (100/120 mesh) or equivalent.
Operation of this column at high temperatures will seriously
reduce Its useful period of performance. This column was
used to develop the method performance statements in Section
15. Alternative columns may be used In accordance with the
provisions described in Section 12.1.
5.6.2 Column 2 - 180 cm long x 2 mm ID glass, packed with 32
SP-2401 on Supelcoport (100/120 mesh) or equivalent.
5.6.3 Detector - Thermionic bead In the nitrogen mode. This
detector has proven effective 1n the analysis of wastewaters
for the parameters listed In the scope and was used to
develop the method performance statements In Section 15.
Alternative detectors, Including a mass spectrometer, may be
used in accordance with the provisions described in Section
12.1.
6. Reagents _
6.1 Reagent water - Reagent water 1s defined as a water in which an
Interferent is not observed at the method detection limit of each
parameter of Interest.
6.2 Acetone, methy!ene chloride - Pesticide quality or equivalent.
6.3 Sodium sulfate - (ACS) Granular, anhydrous. Heat treat in a
shallow tray at 400°C for a minimum of 4 n to remove phthalates
and other Interfering organic substances. Alternatively, heat 16 h
at 450-500°C in a shallow tray or Soxhlet extract with methylene
chloride for 48 h.
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6.4 Stock standard solutions (1.00 yg/uU - Stock standard solutions
may be prepared from pure standard materials or purchased as
certified solutions.
6.4.1 Prepare stock standard solutions by accurately weighing
approximately 0.0100 g of pure material. Dissolve the
material in pesticide quality acetone and dilute to volume
1n a 10-mL volumetric flask. Larger volumes may be used at
the convenience of the analyst. If compound purity is
certified at 96X or greater, the weight may be used without
correction to calculate the concentration of the stock
standard. Commercially prepared stock standards may be used
at any concentration if they are certified by the manufac-
turer or by an independent source.
6.4.2 Transfer the stock standard solutions into TFE-fluorocarbon-
sealed screw cap vials. Store at 4°C and protect from
light. Frequently check stock standard solutions for signs
of degradation or evaporation, especially just prior to
preparing calibration standards from them.
6.4.3 Stock standard solutions must be replaced after six months
or sooner if comparison with check standards indicates a
problem.
7. CalIbrati on
7.1 Establish gas chromatographlc operating parameters equivalent to
those Indicated in Table 1. The gas chromatographic system may be
calibrated using either the external standard technique (Section
7.2) or the Internal standard technique (Section 7.3).
7.2 External standard calibration procedure:
7.2.1 For each parameter of interest, prepare calibration stan-
dards at a minimum of three concentration levels by adding
accurately measured volumes of one or more stock standards
to a volumetric flask and diluting to volume with acetone.
One of the external standards should be representative of a
concentration near, but above, the method detection limit.
The other concentrations should correspond to the range of
concentrations expected in the sample concentrates or should
define the working range of the detector.
7.2.2 Using injections of 1 to 5 uL of each calibration standard,
tabulate peak height or area responses against the mass
Injected. The results can be used to prepare a calibration
curve for each parameter. Alternatively, the ratio of the
response to the mass Injected, defined as the calibration
factor (CF), may be calculated for each parameter at each
standard concentration. If the relative standard deviation
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of the calibration factor is less than 101 over the working
range, the average calibration factor can be used in place
of a calibration curve.
7.2.3 The working calibration curve or calibration factor must be
verified on each working shift by the measurement of one or
nore calibration standards. If the response for any para-
meter varies from the predicted response by more than ±10*,
the test must be repeated using a fresh calibration stan-
dard. Alternatively, a new calibration curve or calibration
factor must be prepared for that parameter.
7.3 Internal standard calibration procedure. To use this approach, the
analyst must select one or more internal standards similar in
analytical behavior to the compounds of interest. The analyst must
further demonstrate that the measurement of the internal standard
1s not affected by method or matrix interferences. Due to these
limitations, no internal standard applicable to all samples can be
suggested.
7.3.1 Prepare calibration standards at a minimum of three con-
centration levels for each parameter of interest by adding
volumes of one or more stock standards to a volumetric
flask. To each calibration standard, add a known constant
amount of one or more internal standards, and dilute to
volume with acetone. One of the standards should be
representative of a concentration near, but above, the
method detection limit. The other concentrations should
correspond to the range of concentrations expected 1n the
sample concentrates, or should define the working range of
the detector.
7.3.2 Using injections of 1 to 5 uL of each calibration standard,
tabulate the peak height or area responses against the
concentration for each compound and Internal standard.
Calculate response factors (RF) for each compound as follows:
RF « (AsC1s)/(Ais Cs)
where:
• AS * Response for the parameter to be measured.
A-fs * Response for the Internal standard.
C-jS » Concentration of the Internal standard in ug/l.
Cs « Concentration of the parameter to be measured
in
If the RF value over the working range 1s constant, less
than 10% relative standard deviation, the RF can be assumed
to be invariant and the average RF may be used for calcula-
tions. Alternatively, the results may be used to plot a
calibration curve of response ratios, As/A-js against RF.
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7.3.3 The working calibration curve or RF must be verified on each
working shift by the measurement of one or more calibration
standards. If the response for any parameter varies from
the predicted response by more than ±102, the test must be
repeated using a fresh calibration standard. Alternatively,
a new calibration curve must be prepared for that compound.
7.4 Before using any cleanup procedure, the analyst oust process a
series of calibration standards through the procedure to validate
elution patterns and the absence of interference from the reagents.
8. Quality Control
8.1 Each laboratory using this method is required to operate a formal
quality control program. The minimum requirements of this program
consist of an initial demonstration of laboratory capability and
the analysis of spiked samples as a continuing check on perfor-
mance. The laboratory is required to maintain performance records
to define the quality of data that is generated.
8.1.1 Before performing any analyses, the analyst must demonstrate
the ability to generate acceptable accuracy and precision
with this method. This ability is established as described
in Section 8.2.
8.1.2 In recognition of the rapid advances occurring in chroraato-
graphy, the analyst is permitted certain options to improve
the separations or lower the cost of measurements. Each
time such modifications to the method are made, the analyst
1s required to repeat the procedure 1n Section 8.2.
3.1.3 The laboratory must spike and analyze a minimum of 102 of
all samples to monitor continuing laboratory performance.
This procedure 1s described in Section 8.4.
8.2 To establish the ability to generate acceptable accuracy and
precision, the analyst must perform the following operations.
8.2.1 Select a representative spike concentration for each
compound to be measured. Using stock standards, prepare a
quality control check sample concentrate in acetone 1000
times more concentrated than the selected concentrations.
8.2.2 Using a pipet, add 1.00 mL of the check sample concentrate
to each of a minimum of four 1000-mL aliquots of reagent
water. A representative wastewater may be used in place of
the reagent water, but one or more additional aliquots must
be analyzed to determine background levels, and the spike
level must exceed twice the background level for the test to
be valid. Analyze the aliquots according to the method
beginning in Section 10.
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8.2.3 Calculate the average percent recovery (R), and the standard
deviation of the percent recovery (s), for the results.
Wastewater background corrections must be made before R and
s calculations are performed.
3.2.4 Using the appropriate data from Table 2, determine the
recovery and single operator precision expected for the
method, and compare these results to the values calculated
1n Section 8.2.3. If the data are not comparable, review
potential problem areas and repeat the test.
8.3 The analyst must calculate method performance criteria and define
the performance of the laboratory for each spike concentration and
parameter being measured.
8.3.1 Calculate upper and lower control limits for method perfor-
mance as follows:
Upper Control Limit (UCL) » R + 3 s
Lower Control Limit (LCL) ' R - 3 s
where S and s are calculated as 1n Section 8.2.3.
The UCL and LCL can be used to construct control charts6
that are useful 1n observing trends 1n performance.
8.3.2 The laboratory must develop and maintain separate accuracy
statements of laboratory performance for wastewater samples.
An accuracy statement for the method 1s defined as R ± s.
The accuracy statement should be developed by the analysis
of four aliquots of wastewater as described in Section
8.2.2, followed by the calculation of R and s. Alterna-
tlvely.the analyst may use four wastewater data points
gathered through the requirement for continuing quality
control 1n Section 8.4. The accuracy statements should be
updated regularly.6
8.4 The laboratory 1s required to collect in duplicate a portion of
their samples to monitor spike recoveries. The frequency of spiked
sample analysis must be at least 102 of all samples or one spiked
sample per month, whichever 1s greater. One aliquot of the sample
must be spiked and analyzed as described in Section 8.2. If the
recovery for a particular parameter does not fall within the
control limits for method performance, the results reported for
that parameter in all samples processed as part of the same set
must be qualified as described 1n Section 13.3. The laboratory
should monitor the frequency of data so qualified to ensure that 1t
remains at or below 5X.
8.5 Before processing any samples, the analyst must demonstrate through
the analysis of a 1-liter aliquot of reagent water that all
glassware and reagents interferences are under control. Each time
a set of samples is extracted or there is a change in reagents, a
8
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laboratory reagent blank must be processed as a safeguard against
laboratory contamination.
8.6 It 1s recommended that the laboratory adopt additional quality
assurance practices for use with thfs method. The specific
practices that are most productive depend upon the needs of the
laboratory and the nature of the samples. Field duplicates may be
analyzed to monitor the precision of the sampling technique. When
doubt exists over the identification of a peak on the chromatogram,
confirmatory techniques such as gas chromatography with a dissim-
ilar column, specific element detector, or mass spectrometer roust
be used. Whenever possible, the laboratory should perform analysis
of quality control materials and participate in relevant perfor-
mance evaluation studies.
9. Sample Collection, Preservation, and Handling
9.1 Grab samples must be collected in glass containers. Conventional
sampling practices7 should be followed; however, the bottle must
not be prerinsed with sample before collection. Composite samples
should be collected in refrigerated glass containers in accordance
with the requirements of the program. Automatic sampling equipment
must be as free as possible of plastic and other potential sources
of contamination.
9.2 The samples must be iced or refrigerated at 4°C from the time of'
collection until extraction.
9.3 All samples must be extracted within seven days and completely •
analyzed within 40 days of extraction.
10. Sample Extraction _
10.1 Mark the water meniscus on the side of the sample bottle for later
determination of sample volume. Pour the entire sample into a
2-liter separatory funnel.
10.2 Add 60 mi. methylene chloride to the sample bottle, seal, and shake
30 s to rinse the inner walls. Transfer the solvent to the separa-
tory funnel and extract the sample by shaking the funnel for 2 min
with periodic venting to release excess pressure. Allow the
organic layer to separate from the water phase for a minimum of 10
rain. 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 opti-
mum technique depends upon the sample, but may include stirring,
filtration of the emulsion through glass wool, centrlfugation, or
other physical methods. Collect the methylene chloride extract in
a 250-mL Erlenmeyer flask.
10.3 Add a second 60-mL volume of methylene chloride to the sample
bottle and repeat the extraction procedure a second time, combining
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the extracts in the Erlenmeyer flask. Perform a third extraction
in the same manner.
10.4 Assemble a Kuderna-Danish (K-0) concentrator by attaching a 10-mL
concentrator tube to a 500-mL evaporative flask. Other concentra-
tion devices or techniques may be used in place of the K-0 if the
requirements of Section 8.2 are met.
10.5 Pour the combined extract through a drying column containing about
10 on of anhydrous sodium sulfate, and collect the extract in the
K-0 concentrator. Rinse the Erlenmeyer flask and column with 20 to
30 roL of methylene 'chloride to complete the quantitative transfer.
10.6 Add 1 or 2 clean boiling chips to the evaporative flask and attach
a three-ball Snyder column. Prewet the Snyder column by adding
about 1 mL methylene chloride to the top. Place the K-D apparatus
on a hot water bath, 60 to 65°C, so that the concentrator tube is
partially immersed in the hot water, and the entire lower rounded
surface of the flask is bathed with hot vapor. Adjust the vertical
position of the apparatus and the water temperature as required to
complete the concentration in 15 to 20 min. At the proper rate of
distillation, the balls of the column will actively chatter but the
chambers will not flood with condensed solvent. When the apparent
volume of liquid reaches 1 mL, remove the K-0 apparatus and allow
1t to drain and cool for at least 10 rain.
10.7 Increase the temperature of the hot water bath to about 70°C.
Momentarily remove the Snyder column, add 50 mL of acetone and a
new boiling chip and reattach the Snyder column. Pour about 1 mL
of acetone into the top of the Snyder column and concentrate the
solvent extract as before. Elapsed time of concentration shou-ld be
5 to 10 min. When the apparent volume of liquid reaches 1 mL,
remove the K-0 apparatus and allow it to drain and cool for at
least 10 min.
10.8 Remove the Snyder column and rinse the flask and its lower joint
Into the concentrator tube with 1 to 2 mL of hexane and adjust the
volume to 10 mL. A 5-mL syringe is recommended for this operation.
Stopper the concentrator tube and store refrigerated if further
processing will not be performed immediately. If the extracts will
be stored longer than two days, they should be transferred to
TFE-fluorocarbon-sealed screw-cap vials. Analyze by gas chromato-
graphy.
10.9 Determine the original sample volume by refilling the sample bottle
to the mark and transferring the water to a 1000-mL graduated
cylinder. Record the sample volume to the nearest 5 mL.
11. Cleanup and Separation
11.1 Cleanup procedures may not be necessary for a relatively clean
sample matrix. If particular circumstances demand the use of a
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cleanup procedure, the analyst must determine the elutlon profile
and demonstrate that the recovery of each compound of Interest for
the cleanup procedure 1s no less than 852.
12. Sas Chromatography
12.1 Table 1 summarizes the recommended operating conditions for the gas
chromatograph. Included 1n this table are estimated retention
times and method detection limits that can be achieved by this
method. An example of the separations achieved by Column 1 1s
shown 1n Figure 1. Other packed columns, chromatographic condi-
tions, or detectors may be used if the requirements of Section 8.2
are met. 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 the requirements of Section
8.2 are met.
12.2 Calibrate the system dally as described 1n Section 7.
12.3 If the Internal standard approach is being used, add the internal
standard to sample extracts immediately before injection into the
Instrument. Mix thoroughly.
12.4 Inject 1 to 5 uL of the sample extract using the solvent-flush
technique.8 Record the volume injected to the nearest 0.05 yL,
and the resulting peak size In area or peak height units. An
2 automated system that consistently injects a constant volume of
extract may also be used.
12.5 The width of the retention time window used to make identifications
should be based upon measurements of actual retention time varia-
tions of standards over the course of a day. Three times the
standard deviation of a retention time can be used to calculate a
suggested window size for a compound. However, the experience of
the analyst should weigh heavily in the Interpretation of chromato-
graras.
12.6 If the response for the peak exceeds the working range of the
system, dilute the extract and reanalyze.
12.7 If the measurement of the peak response is prevented by the
presence of Interferences, cleanup 1s required.
13. Calculations _
13.1 Determine the concentration of individual compounds in the sample.
13.1.1 If the external standard calibration procedure is used,
calculate the amount of material Injected from the peak
response using the calibration curve or calibration factor
in Section 7.2.2. The concentration in the sample can be
calculated as follows:
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(A)(Vt)
Concentration, ug/L * —nj
where:
A « Amount of material Injected, in nanograms.
V-j » Volume of extract injected In uL.
V^ » Volume of total extract in uL.
Vs « Volume of water extracted in mL.
13.1.2 If the internal standard calibration procedure was used,
calculate the concentration in the sample using the response
factor (RF) determined 1n Section 7.3.2 as follows:
(AJCI.)
Concentration, ug/l * (A1s)(RF)(VQ)
where:
A; • Response for the parameter to be measured.
A-JS » Response for the internal standard.
Is * Amount of internal standard added to each
extract in ug.
V0 « Volume of water extracted, in liters.
13.2 Report results in micrograms per liter without correction for
recovery data. When duplicate and spiked samples are analyzed,
report all data obtained with the sample results.
13.3 For samples processed as part of a set where the laboratory spiked
sample recovery falls outside of the control limits in Section 3.3,
data for the affected parameters must be labeled as suspect.
14. 6C/MS Confirmation
14.1 It is recommended that SC/MS techniques be judiciously employed to
support qualitative compound 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 compound. 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 s per scan utilizing a 70 V (nominal) electron energy
in the electron impact 1on1zat1on mode. A SC to MS interface
constructed of all-glass or glass-lined materials 1s 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.
14.2 Gas chroraatographic columns and conditions should be selected for
optimum separation and performance. The conditions selected must
be compatible with standard SC/MS operating practices. Chromato-
graphic tailing factors of less than 5.0 must be achieved.9
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14.3 At the beginning of each day that confirmatory analyses are to be
performed, the GC/MS system must be checked to see that all
decaf luorgtriphenyl phosphlne (DFTPP) performance criteria are
achieved.10
14.4 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 nanograms of
material be injected into the GC/MS. The criteria below must be
met for qualitative confirmation.
14.4.1 All 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 plus or minus
lOt. 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 202 to 401.
14.4.2 The retention time of the compound in the sample must be
within 6 seconds of the same compound in the standard
solution.
14.4.3 Compounds that have very similar mass spectra can be
explicitly identified by SC/MS only on the basis of
retention time data.
- 14.5 Where available, chemical ionization mass spectra may be employed
to aid in the qualitative identification process.
14.6 Should these MS procedures fail to provide satisfactory results,
additional steps may be taken before reanalysis. These may Include
the use of alternate packed or capillary GC columns or additional
cleanup (Section 11).
IS. Method Performance _____
15.1 The method detection limit (MOL) is defined as the minimum concen-
tration of a substance that can be measured and reported with 99*
confidence that the value is above zero.11 The MOL
concentrations listed in Table 1 were obtained using reagent
water
15.2 In a single laboratory (West Cost Technical Services, Inc.), using
effluents from pesticide manufacturers and publicly owned treatment
works (POTW), the average recoveries presented in Table 2 were
obtained.1 The standard deviations of the percent recoveries of
these measurements are also included in Table 2.
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References
T. "Pesticide Methods Evaluation," Letter Reports #6, 12A and 14 for EPA
Contract No. 68-03-2597. Available from U.S. Environmental Protection
Agency, Environmental Monitoring and Support Laboratory, Cincinnati,
Ohio 45263.
2. ASTM Annual Book of Standards, Part 31, 03694, 'Standard Practice for
Preparation of Sample Containers and for Preservation, " American
Society for Testing and Materials, Philadelphia, PA, p. 679, 1980.
3. "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, Aug. 1977.
4. "OSHA Safety and Health Standards, General Industry,' (29 CFR 1910),
Occupational Safety and Health Administration, OSHA 2206, (Revised,
January 1976).
5. "Safety in Academic Chemistry Laboratories," American Chemical Society
Publication, Committee on Chemical Safety, 3rd Edition, 1979.
6. "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
45268, March 1979.
7. ASTM Annual Book of Standards, Part 31, D3370, "Standard Practice for
Sampling Water," American Society for Testing and Materials,
Philadelphia, PA, p. 76, 1980.
8. Burke, J. A., "Sas Chromatography for Pesticide Residue Analysis; Some
Practical Aspects," Journal of the Association of Official Analytical
"Chemists, 48, 1037 (1965).\
9. McNalr, H.M. and BoneTH, E. J., "Basic Chromatography," Consolidated
Printing, Berkeley, California, p. 52, 1969.
10. Elchelberger, J.W., Harris, L.E., and Budde, W.L. "Reference Compound to
Calibrate Ion Abundance Measurement 1n Sas Chromatography-Mass
Spectrometry," Analytical Chemistry, 47, 995 (1975).
11. Slaser, J.A. et.al, "Trace Analysis for Wastewaters," Environmental
Science & Technology, J5_, 1426 (1981). .. _
14
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TABLE 1
CHROMATOGRAPHIC CONDITIONS AND METHOD DETECTION LIMITS
Parameter
Terbacll
Bromacll
Hex ari none
Trfcyclazole
Metribuzin
Tr1ad1raefon
Oeet
ec
Column
la
la
Ta
Ib
2a
2a
2b
Retention
Time
(M1n)
2.1
3.7
7.6
3.5
2.4
4.1
4.6
Method
Detection Limit
(ug/L)
NO
2.38
0.72
NO
0.46
0.78
3.39
ND * Not determined
Column la conditions: Supelcoport (100/120 mesh) coated with 3% SP-2250D8
packed in a 180 cm long x 2 mm ID glass column with nitrogen carrier gas at
a flow rate of 30 mL/m1n. Column temperature, programmed: Initial 210°C,
hold for 1 rain, then program at 10°C to 2SO°C and hold. A thermionic
bead detector in the nitrogen mode was used to calculate the MOL.
Column Ib conditions: Same as Column la, except column temperature
Isothermal at 240°C.
Column 2a conditions: Supelcoport (100/120 mesh) coated with 32 SP-2401
packed in a 180 on long x 2 mm ID glass column with nitrogen carrier gas at
a flow rate of 30 mL/m1n. Column temperature, programmed: initial 160°C,
programmed at injection at 10°C/min to 230°C.
Column 2b conditions: Same as Column 2a, except temperature programed:
Initial 130°C, hold for 1 min, then program at 12°C/min to 200°C.
T5
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TABLE 2
SINGLE OPERATOR ACCURACY AND PRECISION
Parameter
BromacH
Oeet
Hexazlnon
Metrlbuzin
TerbacH
Trladmefon
Tricyclazole
Sample
Type
OW
MW
MW
OW
MW
MW
OW
MW
MW
OW
MW
MW
OW
PW
IW
MW
MW
Spike
(ug/L)
5
11.1
333
5.3
5.2
515
4.9
10.1
369
5.2
32.8
656
5.2
515
154.5
12.3
303
Number
of
Replicates
7
7
7
7
7
7
7
7
7
6
7
7
6
4
7
7
7
Mean
Recovery
(X)
92.2
89
95
99.1
92.6
94.2
86.6
92.2
94.0
98.2
106.7
101
126
71.8
70.4
69
98
Standard .
Deviation
(X)
13.9
3.9
0.3
18.4
5.9
2.2
4.1
5.3
1.9
2.7
3.6
1.2
6.0
4.5
3.3
1.9
1.2
DW * Reagent water
MW * Municipal wastewater
PW * Process water, pesticide manufacturing
IW • Industrial wastewater, pesticide manufacturing
16
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Terbadl
Hexazinone
t
4 5
Minutes
8
Figure 1. Gas chromatogram of organonitrogen pesticides on Column 1
For conditions, s.ee Table 1.
17
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