United States
Environmental Protection
Agency
Environmental Monitoring
Systems Laboratory
Las Vegas NV 89114
Research and Development
EPA/600/S4-87/009 June 1987
&EPA Project Summary
Single Laboratory
Validation of
EPA Method 8140
L. D. Betowski and P. J. Marsden
Method 8140. Organophosphorous
Pesticides Parameters, of SW-846 was
validated for use in the determination
of 27 analytes in a single laboratory
study. The method can be used for the
analysis of 26 Organophosphorous pa-
rameters in water, soil, and hazardous
waste; the method is not suitable for
monocrotophos because it showed poor
recovery from soil and water. The per-
formance of several GC columns, both
packed and capillary, was established
for the analysis of organophosphates.
The use of megabore capillary GC
columns over the use of packed columns
specified in the current method is re-
commended for multiresidue Organ-
ophosphorous analysis. Two phosphorus
specific detectors, the flame photo-
metric (FPD) and nitrogen phosphorus
(NPD). were compared in terms of
linearity, specificity, and sensitivity.
Sample preparation and analysis tech-
niques for organophosphates in aqueous
and solid matrices were tested for
ruggedness in order to identify critical
method parameters. A proposed modifi-
cation of Method 8140 is included
together with accuracy and precision
data for the determination of 26 method
analytes in soil and water samples.
Limited recovery data is also provided
for additional Organophosphorous com-
pounds amenable to the method.
This Project Summary was developed
by EPA's Environmental Monitoring
Systems Laboratory, Las Vegas, NV, to
announce key findings of the research
project that Is fully documented In a
separate report of the same title (see
Project Report ordering Information at
back).
Introduction
Method 8140, published in SW-846,
Second Edition, is reported applicable to
the analysis of 20 Organophosphorous
pesticides with detection limits in the
range of 0.1 to 5 ng/L for water. The
method is a straightforward procedure in
which samples are extracted with organic
solvent, are concentrated, and are
analyzed by GC with a phosphorus
specific detector. Water samples are
extracted by the use of one of two
alternate procedures. Method 3510
(separatory funnel extraction) or Method
3520 (continuous liquid-liquid extraction).
Two alternate preparation techniques are
specified for soil samples and nonaqueous
hazardous waste samples. Method 3540
(Soxhlet extraction) and Method 3550
(extraction by sonication). The gas
chromatographic separation of the or-
ganophosphates is accomplished by using
three packed columns, 5 percent SP-
2401 on Supelcoport, 3 percent SP-2401
on Supelcoport, or 10 percent SE-54 on
Gas Chrom Q (Teflon column). Two
alternate phosphorus specific GC detec-
tors are recommended: the nitrogen
phosphorus (NPD) or flame photometric
(FPD).
This report includes (1) a comparison
of the recovery of 27 potential method
analytes by using the sample preparation
techniques specified for water and soil,
(2) an evaluation of several packed and
capillary columns with retention times
for organophosphates of regulatory in-
terest, and (3) a comparison of linearity,
sensitivity, and detection limits of NPD
and FPD detectors. A study of the ap-
plicability of cartridge cleanup techniques
for analytes of Method 8140 is also
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presented. Results of three ruggedness
tests applied to sample preparation and
analysis techniques are included with
critical method criteria. Method bias and
precision were established by conducting
recovery studies of method parameters
spiked at multiple concentration into each
sample matrix.
Experimental Procedures
Method 8140 presently specifies the
use of gas chromatography (GC) with
single phase packed columns for the
separation and quantitative determination
of organophosphorous compounds. In this
study, the evaluation of four packed GC
columns was conducted: (1) 5 percent
SP-2401; (2) 6 percent OV-210/4 percent
SP-2100; (3) 10 percent DEGS; and (4)
10 percent SP-2330. All columns were
180 cm x 2 mm ID, with 100/120-mesh
Supelcoport used as packing support. Both
the FPD and NPD were used as detectors
for the organophosphorous pesticides.
In addition to the evaluation of the
above packed columns, the use of 30-m
megabore capillary columns for the
analysis of the organophosphorous
pesticides was evaluated; the SPB-608
and the DB-210 columns were recom-
mended in the modified Method 8140.
The retention times and temperature
programs for Method 8140 analytes on
these two columns are shown in Table 1.
Method 8140 was evaluated for spiked
water extracted by using Method 3510
(separatory funnel shakeout) or Method
3520 (continuous extractor) and for soil
and solid wastes extracted by using
Methods 3540 (Soxhlet extraction) or
3550 (sonication).
Ruggedness testing of Method 8140
was applied to the extraction of both
water samples and soil samples. Seven
variables were changed for the testing of
the water samples. For the water samples,
two conditions were tested for each of
the following variables: duration of ex-
traction, amount of sample, storage of
extracts prior to analysis, amount of
extraction solvent, concentration method,
injection volume, and quantification
method. For the soil samples, two condi-
tions were tested for the following vari-
ables: sonication power, percent moisture
of soil, extraction solvent, length of
sonication, post-extraction filtration
method, final concentration step, and use
of GPC cleanup. In addition, a second
ruggedness testing on soil was used in
which the following variables were
changed: type of extraction, percent
moisture, spike level, filtration of extract
through sodium sulfate, concentration
method, length of storage of uncon-
centrated extract, and use of GPC cleanup.
TaWe 1. Capillary Column Retention
Times For Method 8140 Analytes
Capillary Column
Compound
Azinphos methyl
Bolster
Chlorpyrifos
Coumaphos
Demeton, O.S
Diazinon
Dichlorous
Dimethoate
Disulfoton
EPN
Ethoprop
Fensulfothion
Fenthion
Malathion
Merphos
Mevinphos
Monocrotophos
Naled
Parathion, ethyl
Parathion. methyl
Phorate
Ronnel
Sulfotep
TEPP
Tetrachlorvinphos
Tokuthion
Trichloronate
SPB608
38.04
35.08
26.88
38.87
15.90
20.02
7.91
20.18
19.96
36.71
16.48
35.20
29.45
28.78
21.73
12.88
20.11
17.40
27.62
23.71
17.52
22.98
18.02
5.12
32.99
24.58
28.41
DB210
37.24
37.55
25.18
39.47
17.24
19.68
12.79
27.96
20.66
36.74
18.67
36.80
28.86
32.58
32.44
18.44
31.42
19.35
33.39
32.17
18.19
23.19
19.58
10.66
33.68
39.94
29.95
Temperature Program used for Both Capillary
Columns:
Initial temperature
Initial time
Rate
Final temperature
Ho/dl
Rate
Final temperature
Hold 2
50°C
1 minute
5°C/minute
140°C
10 minutes
10°C/minute
240°C
10 minutes
Results and Discussion
The single laboratory evaluation of
Method 8140 has resulted in a modifica-
tion of the method. This modified method
which proposes the use of megabore
capillary columns is presented as an
appendix to the Project Report.
The linearity range and response factor
for 27 Method 8140 analytes with a NPD
are presented in Table 2. Similar data
with an FPD are given in Table 3.
Two critical method variables for the
extraction of soil were identified by rug-
gedness testing. Extraction with 1:1
methylene chloride/acetone (v/v) resulted
in improved recoveries over methylene
chloride alone. The recoveries of or
ganophosphorous pesticides were poore
following GPC cleanup versus no GPC. li
a second ruggedness test on the soil, thi
spike level appeared to affect analyt
recovery significantly. A 10-fold increasi
in spiking concentration resulted in .
significant improvement in sample re
covery. No critical method variables wen
identified in the ruggedness test for wate
samples. The overall standard deviatioi
calculated from the ruggedness testini
for water was 5.2 percent.
The recoveries were 50 to 80 percen
for most spiked organophosphorous com
pounds when use was made of thi
Soxhlet extractor, while only 40 to 71
percent were recovered for these sami
analytes by using sonication. The relativi
standard deviation for the method unde
either Soxhlet extraction or sonication fo
most analytes is roughly equivalent (51<
15 percent).
Although the extraction procedure wai
not identified as a critical method variable
analyte recoveries from water at low am
medium concentrations were general!1
lower for continuous liquid extractioi
(Method 3520) versus separatory funne
(Method 3510) extraction. This may havi
been due to hydrolysis of analyte in thi
longer continuous extraction process. I
is important to remember that this dif
ference was observed in the extraction o
clean water. For some environmenta
samples, the loss of analytes in emulsion;
formed in the separatory funnel coulc
make continuous liquid extraction the
preferred method.
Conclusion and
Recommendations
The present Method 8140 is a packet
column technique suitable for the analysis
of twenty compounds. Because then
were shortcomings in this method in th<
area of GC resolution when it was applie<
to a longer list of analytes, a modifiec
method has been proposed. The modifie(
Method 8140 of SW-846 was applied tc
the determination of 27 organophos
phorous analytes in water and soil. Thi!
method has been validated for use witt
26 of these compounds. The methoc
cannot be used for monocrotophos since
recoveries of no greater than 20 percen
were achieved for this compound. Thi!
new version of Method 8140 allows the
use of megabore capillary columns: t
polar column (DB-210 or equivalent) if
recommended as the primary column
and a moderate polarity column (SP-60f
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or equivalent) is proposed for the second-
ary column. The modified method repre-
sents an improvement over the older
technique and can be used to generate
data of good quality with excellent
repeatability.
The modified Method 8140 requires
that aqueous samples be extracted with
methylene chloride, and that solids be
extracted with a 1:1 methylene chloride/
acetone (v/v) solvent mixture. A caution
has been added that the analyst should
use a drying agent only if necessary,
since single laboratory results indicate
that some organophosphorous analytes
are lost during drying with sodium sulfate.
The laboratory is allowed to use either
Kuderna-Danish (K-D) or rotary evapora-
tion to reduce the volume of sample
extracts. Analysts are cautioned that
samples should not be transferred with
100 percent hexane during sample
workup as the more water soluble or-
ganophosphorous compounds may be lost.
No sample cleanup is required for Method
81 40 nor was one validated for its use.
The information in this document has
been funded wholly or in part by the
United States Environmental Protection
Agency under Contract No. 68-03-1958
to S-CUBED, a Division of Maxwell
Laboratories, Inc., San Diego, California.
It has been subject to the Agency's peer
and administrative review, and it has
been approved for publication as an EPA
document
Table 2. Response Factors For 27 Method 8140 Analytes on a Nitrogen-Phosphorus
Detector .
Compound
Azinphos methyl
Bolster
Chlorpyrifos
Coumephos
Demeton
Diazinon
Dichlorvos
Dimethoate
Disulfoton
EPN
Ethoprop
Fensulfothion
Fenthion
Malathion
Merphos
Mevinphos
Monocrotophos
Naled
Parathion. ethyl
Parathion, methyl
Phorate
Ronnel
Sulfotep
TEPP
Tetrachlorvinphos
Tokuthion
Trichloronate
ND = Not determined.
Table 3. Response
Compound
Azinphos methyl
Bolster
Chlorpyrifos
Coumaphos
Demeton
Diazinon
Dichlorvos
Dimethoate
Disulfoton
EPN
Ethoprop
Fensulfothion
Fenthion
Malathion
Merphos
Mevinphos
Monocrotophos
Naled
Parathion, ethyl
Parathion, methyl
Phorate
Ronnel
Sulfotep
TEPP
Tetrachlorvinphos
Tokuthion
Trichloronate
Range (ng)
5-500
0.545-545
5.2-520
1.05-525
13.7-274
5.8-580
4.76-4760
1.07-107
0.720-144
O.62-620
0.61-610
6.9-575
7.45-745
1.2-60O
42.6-4260
7.05-705
42.6-4260
—
1.35-675
1.28-640
1.39-139
0.525-210
6.67-266
6.52-6520
1.03-515
1.39-695
—
Factors For 27 Method 8140 Analytes on a
Range (ng)
5-500
0.545-218
O.52-520
0.525-525
—
1.16-232
4.76-4760
0.535-535
0.720-720
0.62-248
O.61-61O
0.690-690
0.745-745
0.60-60O
8.51-17OO
14.1-705
8.57-1700
10-5OO
0.675-675
0.640-640
1.39-278
0.525-525
0.665-266
13.0-6520
0.515-515
0.695-695
0.5-100
Response Factor
IResponse/ng)
2.46x10*
6.85 xlO3
6.27x10*
2.34 x 1O4
1.10x10*
1.68x10*
2.05x10*
2.29x10*
5.42 x 10s
1.61 x 1O*
3.81 x 1O*
3.88x10*
5.15x10*
3.64x10*
4.48 xlO3
2.09x10*
2.59 xlO3
ND
3.70 x 1O*
2.74x10*
1.94x10*
3.97 xlCf
6.78x10*
3.71 xlO3
1.67x 1O3
2.21 x 10*
ND
Flame Photometric Detector
Response Factor
(Response/ng)
2.28x10*
5.12x10*
6.27x10*
2.49 x 10*
ND
8.56 x 10*
3.08 xlO3
2.77x10*
2.79 x 10*
4.38x10*
3.29 x 1O*
1.86 xlO*
2.95x10*
2.95 x 1O*
2.48x10*
2.38 x 1O*
2.47 xlO3
1.46 xlO3
3.53 xlO*
2.76x10*
3.04 x 10*
3.35x10*
6.97x10*
2.90 xlO2
3.11 x 10*
1.96x10*
2.98x10*
ND = Not determined.
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PaulJ. Marsden is with Maxwell Laboratories. Inc., La Jolla, CA 92038-1620;
the EPA author Leon D. Betowski is with the Environmental Monitoring
Systems Laboratory, Las Vegas, NV89114.
Llewellyn Williams is the EPA Project Officer (see below).
The complete report, entitled "Single Laboratory Validation of EPA Method
8140." (Order No. PB87-177 507/A S; Cost: $ 18.95, subject to change} will
be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Monitoring Systems Laboratory
U.S. Environmental Protection Agency
P.O. Box 15027
Las Vegas. NV 89114
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
U.S.CFfiC'iAi . y*
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Official Business
Penalty for Private Use $300
EPA/600/S4-87/009,
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