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PB85-238608
Evaluation of 10 Pesticide Kathods
Battelle Columbus Labs., OH
Prepared for
Environmental Monitoring and Support Lab.
Cincinnati, OH
Jul 85
EJBD
ARCHIVE
EPA
600-
4-
85-
050
U5, Department of Conanwce
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p&i>5-23*>t»0a
EPA/600/4-85/050
July 1985
EVALUATION OF 10 PESTICIDE METHODS
N»
CO T.M. Engel, J.S. Warner, and W.H. Cooke
•^ Battelle Columbus Laboratories
X; Columbus, Ohio 43201
Contract Number 68-03-1760
Work Assignment 11
c. Project Officer
af Thomas Pressley
Physical and Chemical Methods Branch
Environmental Monitoring and Support Laboratory
Cincinnati, Ohio 45268
ENVIRONMENTAL MONITORING AND SUPPORT LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
BPIOOICCO If
NATIONAL TECHNICAL
•
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TECHNICAL REPORT DATA
(Ptrair rraJInstruction* on Iht itittu ttjart comptetmtl
2.
4. TITLE AND SUBTITLE
Evaluation of 10 Pesticide Methods
S REPORT DATE
July 1985
6 PERFORMING ORGANIZATION CODE
7. AUTHORIS)
8. PERFORMING ORGANIZATION REPORT NO.
T.H. Ennel, J.S. Darner, and V.M. Cooke
9 PERFORMING ORGANIZATION NAME ANO ADDRESS
Battelle Colunbus Laboratories
505 King Avenue
Columbus. Ohio 43201
10. PROGRAM CLEMENTNO.
CBEB1C
11. CONTRACT/GRANT NO
68-03-1760
12. SPONSORING AGENCV NAME ANO ADDRESS
U.S. Environmental Protection Agency
Office of Research and Development
Environmental Monitoring and Support Laboratory
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final Task Report 4/84*12/84
14. SPONSORING AGENCY CODE
EPA/600/06
SUPPLEMENTARY NOTES
16. ABSTRACT
Ten pesticide analysis methods were evaluated. The compounds listed in
each method were analyzed in triplicate at two concentration levels in
reagent water and POTM effluent. Each method was performed as written with
only minor modifications as approved by the USEPA Project Officer. If a
cleanup procedure was included in the analysis metnod, all analyses were
performed with and without the cleanup step.
Resultant data reported included estimated detection limits (EDLs) in
reagent water and recovery data from reagent-water and POTM effluent for
each compound. Suggestions for method improvements were included in the
report where necessary.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c COSATI Tirld/Cioup
18. DISTRIBUTION STATEMENT
Distribute to Public
19. SECURITY CLASS I Thu Report I
Unclassified
21 NO. OF PAGES
147
22 PRICE
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DISCLAIMER
The information in this document has been funded wholly or 1n part by
the United States Environmental Protection Agency under Contract Number
68-05-1760 to Battelle Columbus Laboratories. It has been subject to the
Agency's peer and administrative review, and it has been approved for
publication as an EPA document.
ii
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FOREWORD
Environmental measurements are required to determine the quality of
ambient waters and the character of waste effluents. The Environmental
Monitoring and Support Laboratory-Cincinnati conducts research to:
• Develop and evaluate methods to measure the presence and
concentration of physical, chemical, and radiological
pollutants in water, wastewater, bottom sediments, and
solid waste.
• Investigate methods for the concentration, recovery, and
Identification of viruses, bacteria and other micro-
biological organisms 1n water; and, to determine the
responses of aquatic organisms to water quality.
• Develop and operate an Agency-wide quality assurance
program to assure standardization and quality control
of systems for monitoring water and wastewater.
t Develop and operate a computerized system for instrument
automation leading to improved data collection, analysis,
and quality control.
This report describes the testing and evaluation of ten pesticide
analysis methods to be proposed for the analysis of selected pesticides in
wastewater.
Robert L. Booth, Director
Environmental Monitoring and Support
Laboratory-Ci nci nnati
HI
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ABSTRACT
Ten pesticide analysis methods were evaluated. The compounds listed
1n each method were analyzed in triplicate at two concentration levels in
reagent water and PDTW effluent. Each method was performed as written with
only minor modifications as approved by the EPA Project Officer. If a
cleanup procedure was included in the analysis method, all analyses were
performed with and without the cleanup step.
Resultant data reported included estimated detection limits (EDLs) in
reagent water and recovery data from reagent water and POTW effluent for
each compound. A summary of the resultant data is given in Table 1.
Sugqestions for method improvements are included in the report where
necessary.
iv
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TABLE 1. SUMMARY OF DATA FROM EVALUATION OF 10 PESTICIDE ANALYSIS METHODS
Method
Number
641
641.1
642
642
643
632.1
632.1
632.1
644
614.1
614.1
614.1
614.1
645
645
645
645
645
645
646
646
646
608.2
608.2
608.2
608.2
608.2
608.2
Compound
Thlabendazole
Ethoxyquln
Blphenyl
0 Phenyl phenol
Bentazon
Carbaryl
Napropamlde
Propanll
Picloran
Dioxathton
EP«
Ethion
Terbufos
Alachlor
Sutachlor
Dlphenantd
Lethane
Norflurazon
Fluridone
Basal In
CONB
Dlnocap
Chlorothalonll
DCPA
Dicloran
Methoxychlor
Cis-pernethrln
Trans-pemethrln
EDL,
1.7
6.3
0.04
0.01
1.1
1.2
0.02
0.3
0.3
0.5
12
0.3
0.02
0.2
0.2
0.2
0.1
0.02
0.6
0.0005
0.0005
0.1
0.001
0.003
0.002
0.04
0.2
0.2
Spike
low
10
6.2
2.5
5.0
10
2.0
6.0
0.2
3.0
10
10
10
10
10
10
10
10
10
10
0.1
O.I
O.I
0.02
0.02
0.01
0.1
1.0
1.0
Level. uu/L
Hlgfi
100
62
2S
50
100
20
60
2
30
100
100
100
100
100
100
100
100
100
100
1
1
1
0.2
0.2
0.1
1
10
10
Recovery fran Reagent Water, \M Recovery froa POW Effluent^'
Before Cleanup After Cleanup Before Cleanup After Cleanuo
Low Nigh Low High Lo» High Ion High'
93 1 3 8) t 5 N.C.*4' N.C. 96 5 100 2 N.C. N C
100 i 32 8? i 6 N.C. N.C. 19 14 58 1 N.C. N.C.
74 t 2 SI i 11 N.C. N.C. 56 4 61 t N.C. N.C.
73 t 4 60 i 5 N.C. N.C. 69 2 02 15 N.C. N.C.
92 i 2 81 * 10 N.C. N.C. 94 7 76 2 H.C. N.C.
52 i 10 83 t 13 N.C. M.C. N D. 28 16 N.C. N.C.
103 t 2 102 t 2 N.C. N.C. 96 7 94 3 N.C. N.C.
79 i 6 99 t 3 N.C. N.C. 85 11 77 7 N.C. N.C.
N.O. N.O. N.O. N.O. 52 9 71 0 58 4 68 3
76 i 10 78 t 2 43 • 7 58 • 6 87 IS 91 3 67 6 74 3
1?0 t € 120 t 4 K.O. 65 i 14 85 2 110 6 N. . 62 4
120 t 5 95 i 2 54 • 8 78 t 11 94 5 86 5 59 12 79 3
90 t 3 84 t 1 N.D. 42 t 13 94 5 77 3 57 4 54 8
96 t 3 94 t 2 96 t 3 94 t 3 109 1 102 1 105 3 97 3
96 t 4 93 i 1 95 i 3 93 t 2 103 1 100 1 104 5 95 2
93 i 6 94 i 2 95 t 2 97 t 3 105 1 103 1 95 3 94 4
93 i 6 100 l i 97 2 99 t 4 120 2 123 1 108 4 106 3
69 i 10 92 t 1 69 6 60 t 6 107 1 108 2 76 11 65 17
49 t 16 81 t 15 N. . N.C. 124 6 111 2 N. . N. .
138 t 12 113 t 4 126 B 109 t 10 94 6 113 2 74 3 108 3
91 t 8 69 t 5 89 6 71 t 5 78 2 71 2 76 4 70 2
78 i * 77 • 4 26 3 72 j 14 76 40 72 3 123 53 80 10
l I I
128 t IB 94 t 11 73 t 25 62 j 5 N. . 62 5 71 5 76 2
1 1 I 1
57 t 1 106 t 12 37 . 8 86 t 12 47 12 99 2 40 27 90 14
94 t 9 91 t 2 91 t 6 128 t 17 89 8 85 3 97 14 98 27
111 t 4 "1 i 3 83 . 12 108 i 13 85 . 2 90 2 41 It 95 t 29
N.C. « No cleanup procedure Included In this method.
N.O. • Not detected.
I ' Presence of Interferences precluded determination of compound In sample.
Standard deviation Is Included.
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CONTENTS
Foreword ill
Abstract 1v
Figures vlil
Tables xi
1. Analysis of Thi'abendazole in Wastewater by Liquid Chromatography . 1
Introduction 1
Conclusions 2
Experimental 2
Quality Assurance 3
Results and Discussion 4
Recommendations 7
2. Analysis of Ethoxyquin in Wastewater by Liquid Chromatography. . . 8
Introduction 8
Conclusions 9
Experimental 9
Quality Assurance 10
Results and Discussion 11
Recommendations 11
3. Analysis of Biphenyl and 0-Phenylphenol in Wastewater by
Liquid Chromatography 15
Introduction 15
Conclusions ' 16
Experimental , 16
Quality Assurance 17
Results and Discussion 18
Recommendations 24
4, Analysis of Bentazon in Wastewater by Liquid Chromatography. ... 25
Introduction 25
Conclusions 26
Experimental 26
Quality Assurance 27
Results and Discussion 28
Recommendations 31
5. Analysis of Carbamate and Amide Pesticides in Wastewater by
Liquid Chromatography 32
Introduction 32
Conclusions 33
Experimental 34
Quality Assurance 35
Results and Discussion. . 36
Recommendations 37
vi
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CONTENTS (Continued)
6. Analysis of Plcloram In Wastewater by Liquid Chromatography. ... 43
Introduction 43
Conclusions 44
Experimental 44
Quality Assurance ..... ....... 45
Results and Discussion 46
Recommendations 48
7. Analysis of Organophosphorus Pesticides in Hastewater by
Gas Chromatography 51
Introduction 51
Conclusions 52
Experimental 53
Quality Assurance 54
Results and Discussion 55
Recommendations 59
6. Analysis of Certain Amine Pesticides and Lethane in Wastewater
by Gas Chromatography 70
Introduction 70
Conclusions 72
Experimental 72
Quality Assurance 74
Results and Discussion 76
Recommendations 76
9. Analysis of Dinitro Aromatic Pesticides in Wastewater by
Gas Chromatography 87
Introduction 87
Conclusions 89
Experimental 89
Quality Assurance 93
Results and Discussion 93
Recommendations ....... 101
10. Analysis of Organochlorine Pesticides in Wastewater by
Gas Chromatography 106
Introduction 106
Conclusions 108
Experimental ". 108
Quality Assurance Ill
Results and Discussion Ill
Recommendations 123
References 127
vii
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FIGURES
Number Page
1 HPI.C-?luoresconce chromatoqram of (a) POTW effluent, and (b)
POTH effluent spiked with thiabendazole at the 10 ug/L level . 5
Z HPLC-fluorescence chromatoqram of thiabendazole standard equivalent
to 2.5 ug/L in water used to determine method EDL 6
3 HPLC-fluorescence chromatogram of (a) POTW effluent, and (b)
POTW effluent spiked with ethoxyquin at the 62 vg/L level. . . 12
4 HPLC-fluorescer.ee chromatogram of ethoxyquin standard equivalent
to 6.2 ug/L in water used to determine method EOL 13
5 HPLC-UV chromatogram of (a) reagent water and (b) reagent
water spiked with biphenyl and o-phenylphenol at the
2.5 ug/L level 20
6 HPLC-UV chromatogram of (a) POTW effluent and (b) POTW
effluent spiked with biphenyl and o-phenylphenol at the
2.5 uq/L level 21
7 HPLC-UV chromatogram of a biphenyl standard equivalent
to 0.125 ug/L in water used to determine method EDL 22
8 HPLC-UV chromatogram of an o-phenylphenol standard equivalent to
0.025 vg/L in water used to determine method EDL. 23
9 HPLC-UV chromatogram of (a) unspiked POTW effluent, and (b)
POTW effluent spiked with bentazon at the 10 ug/L level. ... 29
10 HPLC-UV chromatoqram of a bentazon standard eouivalent to
0.5 jfl/L in water used for EDL determination 30
11 HPLC-UV chromatogram of (a) reagent water, and (b) reagent
water spiked with the carbamate and amide pesticides at
the 2.0 vg/L level 38
12 HPLC-UV chromatogram of (a) POTW effluent, and (b) POTW
effluent spiked with the carbamate and amide pesticides
at the 2.0 pg/L level 39
13 HPLC-UV chromatogram of carbaryl standard equivalent to
0.5 vg/L in water used to determine method EDL 40
14 HPLC-UV chromatogram of propanil standard equivalent to
0.05 vg/L in water used to determine method EDL 41
15 HPLC-UV chromatogram of napropamide standard equivalent to
0.5 ug/L in water used to determine method EDL 42
16 HPLC-UV chromatogram of (a) POTW effluent, and (b) POTW
effluent spiked with picloram at the 3.0 ug/L level 47
17 HPLC-UV chromatogram of picloram standard equivalent to
1.25 ug/L in water used to determine method EDL 49
18 GC-NPD chromatogram of (a) reagent water, and (b) reagent
water spiked with the organophosphorus pesticides at the
100 yg/L level 57
viii
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Number Page
19 GC-HPO chromatogram of (a) POTW effluent, and (b) fOTW
effluent spiked with the organophosphorus pesticides
at the 100 vg/L level 58
20 GC-NPD chromatogram {using Bead 1} of dioxathion standard
equivalent to 0.5 ug/L in water used to determine method EDI . 62
21 GC-NPD chromatogram (using Bead 1) of EPN standard equivalent
to 0.5 ug/L in water used to determine method 63
22 GC-NPO chromatogram (using Bead 1) of ethlon standard equivalent
to 0.1 yg/L In water used to determine method EDL 64
23 GC-NPD chromatogram (using Bead 1} of terbufos standard
equivalent to 0.01 ug/L in water used to determine method EDL. 65
24 GC-NPD chromatoqram (using Bead 2) of dioxathion standard
equivalent to 1.0 uq/L in water used to determine method EDL • 66
25 GC-NPD chromatogram (using Bead 2) of EPN standard equivalent
to 7.0 ug/L in water used to determine method EOL 67
26 GC-NPD chromatogram (using Bead 2) of ethion standard
equivalent to 0.5 ug/L in water used to determine method EDL. . 68
27 GC-NPD chroir-atoqram (using Bead 2) of terbufos standard
equivalent to 0.2 ug/L in water used to determine method EDL- • 69
2b GC-NPD chromatogram of (a) reagent water, and (b) reagent
water spiked with alachlor, butachlor, diphenamid,
lethane, and norflu'-azon at the 10 ug/L level 78
29 GC-NPO chromatogram of (a) POTW effluent, and (b) POTW
effluent spiked with alachlor, butachlor, diphenamid,
lethane, and norflurazon at the 10 ug/L level 79
30 GC-NPD chromatogram of (a) reagent water, and (b) reagent
water spiked fluridone at the 10 uQ/L level 80
3i GC-NPD chromatogram of (a) POTW effluent, and (b) POTW
effluent spiked with fluridone at the 10 ug/L level 81
32 GC-NPD chromatogram of alachlor solution representing
0.5 ug/L in water used to determine method EDL 82
33 GC-NPD chromatogram of butachlor and diphenamid solution
representing 0.5 yg/L of each in water used to determine
method EDL 83
34 GC-NPD chromatogram of lethane solution representing 1.0 ug/L
in water ysed to determine the method EOL 84
35 GC-NPD chromatogram of norflurazon solution representing
1.0 ug/L in water used to determine method EDL 85
36 GC-NDD chromatogram of fluridone solution representing
1.0 pg/L in water used to determine method EDL 86
37 GC-ECD chromatogram of hexane solution containing basalfn
and CDNB using oven temperatures of (a) 170°C and (b) 200°C. . 91
38 GC-ECD chromatogram of hexane solution containing dinocap
using oven temperatures of (a) 200°C and (b) 230°C 92
39 GC-ECD chromatogram of (a) POTW effluent, and (b) POTW
effluent spiked with basalin and CDNB at the 1.0 ug/L
level, before cleanup 95
40 GC-ECD chromatogram of (a) POTW effluent, and (b) POTW
effluent spiked with dinocap at the 1.0 u9/L» before cleanup . 96
1x
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Number Page
41 GC-ECD chromatogram of (a) POTW effluent, and (b) POTW
effluent spiked with basal in at the 1.0 ug/L level,
after Florisil cleanup 97
42 GC-ECD chromatogram of (a) POTW effluent, and (b) POTW
effluent spiked with CDNB at the 1.0 ug/L level,
after Florisil cleanup * 98
43 GC-ECD chromatogram of (a) POTW effluent, and (b) POTW
effluent spiked with dlnocap at the 1.0 ug/L level,
after Florisil cleanup »
44 GC-ECD chromatogram of basalin standard equivalent to
0.0005 ug/L in water used to determine method EOL 102
45 GC-ECD chromatogram of CDNB standard equivalent to
0.0005 ug/L in water used to determine method EDL 103
46 GC-ECD chromatogram of dinocap standard equivalent to
0.05 vg/L in water used to determine method EDL 104
47 GC-ECD chromatogram of (a) POTW effluent, and (b) POTW
effluent spiked with 0.2 uq/L chlorthalonil, 0.2 wc'L
DCPA, 0.1 ug/L dicloran, and 10 ug/L methoxychlor 113
48 GC-ECD chromatogram of (al POTW effluent, and (b) POTW
effluent spiked with cis-permethrin and trans-permethrin
at the 10 ig/L levels 114
49 GC-ECD chromatogram of (a) POTW effluent, and (b) POTW
effluent spiked with 0.1 vg/L dichloran and 0.02 vg/L
DCPA after Florisil cleanup ''5
50 GC-ECD chromatogram of (a) POTW effluent, and (b) POTH
effluent spiked with 0.2 yg/mL chlorthalonil and
10 ug/L methoxychlor after silica gel cleanup 116
51 GC-ECD chromatogram of (a) POTW effluent, and (b) POTW
effluent spiked with cis-permethrin and trans-permethrin
at the 10 ug/L levels, after silica gel cleanup 117
52 GC-ECO chromatogram of chlorothalonil standard equivalent
to 0.0025 ug/L in water used to determine method EDL 120
53 GC-ECD chromatogram of DCPA standard equivalent to 0.0025 pg/l.
in water used to determine method EDL 121
54 GC-ECD chromatogram of dicloran standard equivalent to
0.0025 ug/L in water used to determine method EDL 122
55 GC-ECD chromatogram of methoxychlor standard equivalent
to 0.05 ug/L in water used to determine method EDL 124
56 GC-ECD chromatogram of cis-permethrin standard equivalent
to 0.1 ug/L in water used to determine method EDL 125
57 GC-ECD chromatogram of trans-permethrin standard equivalent
to 0.1 ug/L in water used to determine method EDL 126
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TABLES
Number Page
1 Summary of data from evaluation of 10 pesticide analysis
methods v
2 Thiabertdazole calibration data 4
3 Recoveries of thiabendazole from water 7
4 Ethoxyqirin calibration data 11
5 Recoveries of ethoxyquin from water 14
6 Biphenyl and o-phenytphenol calibration data 18
7 Recoveries of biphenyl and o-phenylphenol from water 19
8 Bentazon calibration data 28
9 Recoveries of bentazon from water 31
10 Carbaryl, napropamide, and propanil calibration data ...... 36
11 Recoveries of carbar/1. napropamide, and propanil from water . . 37
12 Picioram calibration data 46
13 Recoveries of picloram from water 48
14 Orgdnophosphorus pesticides calibration data (before cleanup). . 56
15 Organopnosphorjs pesticides calibration data {after cleanup) . . 56
16 Recoveries of organophosphorus pesticides from water 60
17 Organophosphorus pesticides EDLs 61
18 Amine pesticides and 1 ethane calibration data 75
19 Recoveries of amine pesticides and lethane from water 77
20 Dinitro aromatic pesticides calibration data .......... 94
21 Recoveries of dinitro aromatic pesticides from water 100
22 Organochlorine pesticides calibration data T12
23 Recoveries of Organochlorine pesticides from water 118
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SECTION 1
ANALYSIS OF THIABENDAZOLE IN WASTEWATER
BY LiqjID CHROMATOGRAPHY
INTRODUCTION
Thiabendazole (I) is used as ? fungicide on various fruits and vegetables.
The IUPAC name for thiabendazole is 2-(thiazol-4-ylJbenzimidazole and its CAS
registry number is 148-79-8. Common synonyms for thiabendazole include TBZ,
Mertect, Tecto, Storite, MC-360, Thiaben, Thibenzole, Bovizole, Eprofile,
Equizole, Omniqole, and Mintezol. Thiabendazole is a colorless powder with
a melting point of 304-305°C; thiabendazole sublimes when heated to 310°C.
Thiabendazole is stable under normal conditions to hydrolysis, light, and
heat. The solubility of thiabendazole is 10 g/L at 25°C and pH 2. Thiaben-
dazole becomes markedly less soluble in water as the pH is raised. The
acute oral LD50 in rats for thiabendazole is 3300 mg/kg (1).
Thiabendazole was originally determined in crops by fluorometry after
extraction with various solvents (2). Several gas chromatographic (GC) methods
have been reported (3-5). These procedures require derivatization of the
thiabendazole prior to GC analysis. Various high performance liquid chromato-
graphic (HPLC) methods have also been reported (6-14,19). These methods are
ultraviolet (UV) (7,9,10,12,13) and fluorescence (6,8,11-14,19) and normal-
phase columns (6,7,9,13). In some cases, base or ion-pairing agents are added
to the HPLC mobile phase to improve thiabendazole peak shape (7-10,14). Host
of the reported methods described the determination of thiabendazole in crops
or body fluids. One method described the determination of thiabendazole in
wastewaters (14). This procedure is identical to the procedure evaluated in
this study. Cleanup methods were not reported for any of these procedures
with the exception of minimal acid/base partitioning procedures.
The method provided by the Project Officer for evaluation for determina-
tion of thiabendazole in wastewaters consisted of acidification of the sample
to solubilize the thiabcndazole; filtration of the sample to remove particulate
1
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matter; readjustment of the sample pH to make 1t more compatible with HPLC
conditions; and analysis of the sample by HPLC using a fluorescence detector.
CONCLUSIONS
An analysis method designed to determine thiabendazole in wastewaters
was found to be acceptable with minor modifications as discussed in the
Recommendations section. The method was applied to reagent water and Columbus
POTW effluent samples spiked at the 10 or 100 pg/L levels with thiabendazole.
Recoveries of thiabendazole from all samples were greater than 81 percent,
Indicating that the filtration step used to remove particulate from the
sample did not cause losses of thiabendazole. The HPLC-fluorescence conditions
used for sample analyses yielded acceptable chromatography, sensitivity, and
selectivity.
EXPERIMENTAL
The following procedure was outlined in the thiabendazole analysis
method:
1. Filter the acidified sample through a 0.45 micron Nylon filter
2. Adjust the pH of the sample to within the range of
7-9 with diluted sodium hydroxide or sulfuric acid
3. Analyze the sample by HPLC with fluorescence
detection using the rollowing conditions:
- 10-micron reverse-phase Ultrasphere ODS,
4.6 mm by 250 nm column;
- isocratic 70 percent methanol/30 percent buffer
(pH 8.2) mobile phase;
- flow rate of 1 mL/min;
- injection volume of 100 pL
- excitation and emission wavelengths of 300 nm
(5-nm slit width) and 360 nm (10-nm slit width),
respectively.
Prior to performance of the analysis method, two modifications were made in
the method after consultation with the EPA Task Officer:
1. A 10-micron reverse-phase Ultrasphere ODS column was
not commercially available, so a 5-micron reverse-
phase Ultrasphere ODS column was substituted.
2. Although an initial pH adjustment step is mentioned
1n Section 2 of the method, no such step appears in
Section 10.1, Sample Preparation. This initial pH
adjustment was included to sol utilize the thiabendazole
in the sample prior to filtration of the sample. The
samples were adjusted to a pH range of 1.0 to 3.0 with
-------
dilute soJium hydroxide or dilute sulfuric acid prior to
filtration as described in Section 7.2 of the method.
Samples processed included the following:
1. Triplicate reagent water samples. Reagent water was
obtained from a Millipore system.
2. Triplicate reagent water samples spiked wi-th thiabendazole
at the 10 ug/L concentration level.
3. Triplicate reagent water samples spiked with thiabendazole
at the 100 ug/L concentration level.
4. Triplicate POTW secondary effluent samples. POTW
secondary effluent was obtained from the City of Columbus.
5. Triplicate POTW secondary effluent samples spiked with
thiabendazole at the 10 pg/L concentration level.
6. 'riplicate POTW secondary effluent samples spiked with
thiabendazole at the 100 yg/L concentration level.
Recoveries were determined by comparison to standard solutions of
thiabendazole prepared at the 10, 50, and 150 yg/L concentration levels
in HPLC mobile phase. Response factors were calculated for the standards
and used to determine concentration levels in the abovementioned reagent
water and POTW effluent samples.
The EDL for thiabendazole, defined as the concentration of thiabendazole
in a sample yielding a signal-to-noise ratio (S/N) of 5, was determined by
injecting standard solutions of thiabendazole prepared in HPLC mobile phase.
The concentrations of these solutions were in the 1 to 10 ug/L range.
QUALITY ASSURANCE
Instrumentation was set up as described in the method. Sensitivity
achieved was approximately equivalent to that reported in the method.
Calibration standards consisted of thiabendazole solutions prepared at the
10, 50, and 100 ug/L concentration levels in HPLC mobile phase. Each calibra-
tion standard was analyzed in duplicate prior to analysis of any evaluation
samples. A selected calibration standard was then analyzed after every five
evaluation standards. Response factors were calculated for each
calibration run by dividing the concentration level in ug/L by the thiabendazole
peak area. Resultant calibration data are reported in Table 2. Response
factors were reproducible over the entire calibration range. A response factor
of 1.64 was used for calculations of thiabendazole concentrations in the
evaluation samples.
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TABLE 2. THIABENDAZOLE CALIBRATION DATA
Concentration
vg/L
10.0
50.0
150.0
Average
Peak
Area
5.9
31.3
91.6
Standard
Deviation,
%
13.
2.
4.
Number of
Replicates
3
3
4
Average
Response
Factor
1.69
1.60
1.64
Standards of thiabendazole were obtained from two independent sources.
Thiabendazole from the reference standards repository of the EPA Health
Effects Research Laboratory (EPA-HERL) was used for preparation of calibra-
tion standards as well as for preparation of the evaluation samples. A test
calibration standard was also prepared at the 50 pg/L concentration level
from thiabendazole from a chemical supply house. The peak area resulting
from the analysis of the test calibration standard was 9.0 percent lower
than the average peak area obtained from analyses of the EPA-HERL calibration
standard. This indicates that both standards obtained were probably within
10 percent of their specified purities.
RESULTS AND DISCUSSION
Thiabendazole was not detected in unspiked reagent water or POTW effluent
samples. The chromatograms obtained from reagent water and POTW effluent
blanks did not contain any other peaks resulting from interferences. This
was presumably due to the use of fluorescence detection instead of UV detection.
Recoveries of thiabendazole from reagent water and POTW effluent were greater
than 81 percent. Thiabendazole recovery data are given in Table 3. Examples
of chromatograms obtained from the analyses of aliquots of POTW effluent
unspiked and spiked with thiabendazole at the 10 ug/L level are shown in
Figure 1. Recoveries were reproducible with standard deviations of the
percent recovery data being lower than 5.3
The EDL for thiabendazole was determined by analyzing a 2.5 vg/L standard
solution of thiabendazole in HPLC mobile phase; the resultant chromatogram is
shown in Figure 2. This solution yielded a S/N equal to 7.3. The EDL was
calculated to be 1.7 vg/l of thiabendazole in a water sample, which is
approximately equal to the EDL of 1.0 ug/L reported in the method. The EDL
does not take into account any interferences or recovery losses that might
be encountered from a particular matrix.
-------
(a)
2.4 2.8 3.2 3.6 4.0 4.4 4.8 5.2 5.6 6.0
Retention Time, min.
(b)
Thiabendazole
2.4 2.8 3.2 3.6 4.0 4.4 4.8 5.2 5.6 6.0
Retention Time, min.
FIGURE 1. HPLC-FLUORESCENCE CHROMATOGRAMS OF (a) POTW EFFLUENT
AND (b) POTW EFFLUENT SPIKED WITH THIABENDAZOLE AT THE
10 pq/L LEVEL.
-------
«
EDL « 2.5 vg/l x x 5 • 1.7
•
^
•
_:
,,,. r ,,.,.,. I .,-,,., I ,-,_,,. r-,- ,-,-., j , ., , , i , -, , i , r t I I -| i r > r f • T-»-f—^
3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0
FIGURE 2. HPLC-FLUORESCENCE CHROMATOGRAM OF THIABENDAZOLE STANDARD EQUIVALENT TO
2.5 wg/L IN WATER USED TO DETERMINE METHOD EOL.
-------
TABLE 3. RECOVERIES OF THIABENOAZOLE FROM WATER
Spike
Level ,
ng/t-
10
100
10
100
Matrix ta)
1
1
2
2
Blank
Level
vg/L
ND
ND
ND
ND
Percent, *
Recovery***'
93
81
96
700
Standard
Deviation ,%
3
5
5
2
!a) l=Reagent water; 2=Columbus POTW secondary effluent.
b) ND-not detected.
(c) Recovery data are averages of three replicate analyses.
RECOMMENDATIONS
The method was acceptable for determination of thiabendazole in reagent
water and POTW effluents. Samples with exceptionally high paniculate content
may not yield acceptable recoveries of thiabendazole. It is possible that the
thiabendazole may adsorb to the particulate matter and be removed with the
particulate matter during the filtration step. Although the pH adjustment
step prior to filtration may minimize adsorption of the thiabendazole to
particulate matter by making it more soluble in the aqueous media, it must
be recognized that this may be a serious limitation of the method. It is
recommended that this method be studied using wastewaters with high content
of particulate matter, such as sludge.
Some difficulty was encountered while using the method when the sample
pH was adjusted to 7-9 after filtration. No mention is made in the method
that the change in volume due to this pH adjustment must be monitored in
order to more accurately determine thiabendazole concentrations in the sample.
Volume changes were taken into account when the thiabendazole recovery data
presented in Table 2 were calculated. Instructions to measure the volume
change due to the final pH adjustment step should be included in the method.
Alternatively, this final pH adjustment might not be necessary. The
introduction of 100 uL of sample at pH 1-3 may not detectably affect the
resultant chromatography.
-------
SECTION 2
ANALYSIS OF ETKOXYQUIN IN WASTEWATER
BY LIQUID CHROHATOGRAPHY
INTRODUCTION
Ethoxyquin (II) is used as an antioxidant in animal feeds and food
products. The IUPAC name for ethoxyquin is 6-ethoxy-l,2-dihydro-2,2,4-
trimethylquinoline and its CAS registry number is 91-53-2. A synonym for
ethoxyquin is Stop-Scald . Ethoxyquin is not reported to be sensitive to
light, heat, or pH conditions. Residual chlorine has been reported to
degrade ethoxyquin (14). The acute oral LD50 in rats for ethoxyauin is
800-1000 mg/kg.
A GC analysis method has been reported for underivatized ethoxyquin in
crops using a flame ionization detector (FID) or mass spectrometer (MS) for
quantification (15). Close scrutinization of this method indicates non-
linearity of the resultant calibration curve at ethoxyquin concentrations
less than 500 vQ/mL. This is presumably due to adsorption of the amine on
the GC column. An alternative GC method using an electron capture detector
(ECD) for quantification has also been reported, however this method requires
derivatization of the ethoxyquin with heptafluorobutyric anhydride (16).
Various HPLC analysis methods have also been reported (14,17-21). These
methods use UV (18), fluorescence (14,17,19,21), and electrochemical (20)
detection and reverse-phase columns. Most of the reported methods describe
the determination of ethoxyquin in crops. One method describes the determina-
tion of ethoxyquin in wastewaters (14). This procedure is identical to the
procedure evaluated in this study. An adsorption chromatography cleanup
procedure using aluminum oxide is reported (17).
The method provided by the Project Officer for evaluation for determination
of ethoxyquin in wastewaters consisted of filtration of the sample to remove
particulate matter and analysis of the sample by KPLC using a fluorescence
detector.
8
-------
CONCLUSIONS
An analysis method designed to determine ethoxyquin in wastewaters was
not accrptable. The method was applied to reagent water and Columbus POTW
effluent samples spiked at the 10 or 100 vg/L levels with ethoxyquin.
Recoveries of ethoxyquin from POTW effluent were markedly lower than those
obtained from reagent water. It is likely that the ethoxyquin was adsorbed
onto participate matter in the samples and consequently removed during
filtration of the sample. The HPLC-fluorescence conditions used for sample
analyses yielded acceptable chromatography and selectivity. System sensi-
tivity for ethoxyquin was approximately six times that reported in the method,
perhaps due to the use of an excitation wavelength of 365 run instead of the
maximum excitation wavelength of 358 nm given in the literature (1).
EXPERIMENTAL
The following procedure was outlined in the ethoxyquin analysis method:
1. Filter the sample through a 0.45 micron Nylon filter.
2. Analyze the sample by HPLC with fluorescence detection
using the following conditions:
- 5-micron reverse-phase Ultrasphere ODS.
4.6 mm by 250 mm column;
- isocratic 80 percent methanol/20 percent buffer
(pH 8.2) mobile phase;
- flow rate of 1 mL/min;
- injection volume of 100 ul;
- excitation and emission wavelengths of 385 nm
(5-nm slit width) And 450 nm (10-nm slit width),
respectively.
Prior to performance of the analysis method, one modification was made in the
method after consultation with the EPA Task Officer. The method states in
Section Z that the "neutral sample" 1s filtered and then analyzed by direct
aqueous injection. However, no pH adjustment step is described in Section 10.
The samples were adjusted to pH range 6.5 to 7.5 with dilute sodium hydroxide
or dilute sulfuric acid prior to filtration.
Samples processed included the following:
1. Triplicate reagent water samples. Reagent water
was obtained from a Mi 11ipore system
2. Triplicate reagent water samples spiked with t
ethoxyquin at the 10 pg/L concentration level
3. Triplicate reagent water sample*- spiked with
ethoxyquin at the 100 ug/L concentration level*
* The standard used for preparation of the calibration standards and
the evaluation standards was not as pure as specified by the supplier;
all abovementioned samples were spiked at 64 percent of the specified levels.
9
-------
4. Triplicate POTW secondary effluent samples. POTW
secondary effluent was obtained from the City of Columbus.
5. Triplicate POTW secondary effluent samples spiked with
ethoxyquin at the 10 pg/L concentration level*
6. Triplicate POTW secondary effluent samples spiked with
ethoxyquin at the 100 vg/L concentration level*.
Recoveries were determined by comparison to standard solutions of
ethoxyquin prepared at the 10, 50, and 150 wg/L concentration levels in
HPLC mobile phase*. Response factors "ere calculated for the standards and
used to determine concentration levels in the afaovementioned reagent water
and POTW effluent samples.
The EDL for ethoxyquin, defined as the concentration of ethoxyquin in a
sample yielding a 5/W of 5, was determined by injecting standard solutions
of ethoxyquin prepared in HPLC mobre phase. The concentrations of these
solutions were in the 1 to 10 ug/L range.
QUALITY ASSURANCE
Instrumentation was set up as described in the method. Sensitivity
achieved was slightly lower than that reported in the method. Calibration
standards consisted of ethoxyquin solutions prepared at HPLC mobile phase
concentrations of 5,3, 32, and 95 pg/L. Each calibration standard was
analyzed in duplicate prior to analysis of any evaluation samples. A
selected calibration standard was then analyzed after every five evaluation
standards. Response factors were calculated for each calibration run
by dividing the concentration level in pg/L by the resultant ethoxyquin
peak area. Resultant calibration data are reported in Table 4. Response
factors were repeatable over the entire calibration. A resp.v.se factor of
1.42 was used for calculations of ethoxyquin concentrations in the evaluation
samples.
Standards of ethoxyquin were obtained from two independent sources.
Ethoxyquin from the reference standards repository of EPA-HERL was used for
preparation of calibration standards as well as for preparation of the
evaluation samples. A test calibration standard was also prepared at the
50 pg/L concentration level from ethoxyquin from a chemical supply house.
The peak area resulting from the analyses of the EPA-HERL calibration
standards was 64 percent lower than the peak area obtained from analysis
of the test calibration standard. The assumption was made that the purity
specified by EPA-HERL was incorrect. It was therefore assumed that the
calibration standards did not contain ethoxyquin at the 10, 50, and 150 pg/L
levels, but actually contained ethoxyquin at the 6.3, 32, and 95 v9/l levels-
The evaluation samples were therefore spiked with ethoxyquin at the 6.3 and
63 pg/L levels instead of at the 10 and 100 yg/l levels as originally assumed.
10
-------
TABLE 4. ETHOXYQUiN CALIBRATION DATA
Concentration,
ng/L
6.34
31.7
95.1
Average
Peak
Area
4.8
21.8
64.2
Standard
Deviation,
%
3
A
4
Number of
Replicates
3
3
4
Average
Response
Factor
1.31
1.46
1.48
RESULTS AND DISCUSSION
Ethoxyqyin was not detected in unspiked reagent water or POTW effluent
samples. The chromatograms obtained from reagent water and POTW effluent
blanks did not contain any other peaks resulting from interferences. This
was presumably due to the fact that the fluorescence detection as opposed
to UV detection was used. An example of a chromatogram obtained from HPLC
analysis of an unspiked aliquot of POTW effluent is shown in Figure 3.
Recoveries of ethoxyquin from reagent water were greater than 82 percent.
Recoveries of ethoxyquin from POTW effluent were 58 percent or lower.
Ethoxyquin recovery data are given in Table 5. Examples of chromatograms
obtained from analyses of aliquots of POTW effluent unspiked and spiked with
ethoxyquin at the 6.2 ug/L level are shown in Figure 3. Recoveries of
ethoxyquin are generally lower from POTW effluent than from reagent water.
It is likely that the ethoxyquin was adsorbing to particulate matter in the
samples and was removed during the filtration step prior to HPLC analysis.
The EDL for ethoxyquin was determined by analyzing a 6.3 yg/L standard
solution of ethoxyquin in HPLC mobile phase; the resultant chromatogram is
shown in Figure 4. This solution yielded a S/N equal to 5.2. The EDL was
calculated to be 6.1 yg/L of ethoxyquin in a sample, which is approximately
six times the EDL of 1.0 ug/L reported in the method. The EDL does not take
into account any interferences or recovery losses that might be encountered
from a particular matrix.
RECOMMENDATIONS
The EOL determined for ethoxyquin was approximately six times higher than
that reported in the ethoxyquin analysis method. This might be due to slight
differences in instrumentation. However, literature references report a
maximum excitation wavelength of 358 nm instead of 385 nm as specified in
the method (14). Use of this wavelength might increase the sensitivity of
the method.
11
-------
(a)
4.4 4.8 5.2 5.6 6.0 6.4 6.8 7.2 7.6 8.0
Retention Time, min.
(b)
Ethoxyquin
\*
4.4 4.8 5.2 5.6 6.0 6.4 6.8 7.2 7.6 8.0
Retention Time, min.
FIGURE 3. HPLC-FLUORESCENCE CHROMATOGRAM OF (a) POTW EFFLUENT, AND
(b) POTW EFFLUENT SPIKED WITH ETHOXYQUIN AT THE 62 pq/L
LEVEL.
12
-------
EOL - 6.2 yg/L x £•$£ x 5 « 6.2 ug/L
U)
FIGURE 4. HPLC-FLUORESCENCE CHROMATOGRAM OF ETHOXYQUIN STANDARD EQUIVALENT TO 6.2 ug/L
IN WATER USED TO DETERMINE METHOD EDL.
-------
TABLE 5. RECOVERIES OF ETHOXYQUIN FROM WATER
Spike
Level ,
ug/L
6.2
62
6.2
62
Matrix
NO
NO
NO
Percent/ *
Recovery^ '
110
82
19
58
Standard
Deviation, %
32{d)
6
14 (^)
1
(a) l=Reaaent water; 2=Columbus POTW secondary effluent.
(b) ND=not detected.
(c) Recovery data are averages of three replicate analyses.
(d) High standard deviation may be due to spike level of 6.2
is close to the EDL of 6.3 yg/L.
which
Studies in reagent water and POTW effluent revealed matrix dependent
recovery losses. Although these recovery losses may be due to other
characteristics of the POTW effluent, a probable cause is that the ethoxyquin
becomes adsorbed to particulate matter in the POTW effluent and is removed
during the filtration step of the method. Further studies should be conducted
to ascertain if this 1s in fact the cause of the recovery losses. It might
be possible to minimize adsorption of ethoxyquin onto particulate matter by
adjusting matrix conditions so that the ethoxyquin is more likely to remain
in the aqueous portion of the sample. Exactly how to do this is not obvious.
Perhaps a more viable alternative is to remove the ethoxyquin from the
aqueous sample by partitioning the sample with an organic solvent in which
the ethoxyquin is preferentially soluble. This would also serve to remove
particulate matter from the sample prior to HPLC analysis.
14
-------
SECTION 3
ANALYSIS OF BIPHEHYL AND 0-PHENYLPHENOL
IN WASTEWATER BY LIQUID CHROMATOGRAPHY
INTRODUCTION
Biphenyl (III) Is used to Inhibit mycelial growth and spore formation
of citrus fruit roots. The CAS registry number for biphenyl is 92-52-4
and it is also referred to as 1,1'-biphenyl. Biphenyl has a melting point
of 70.5°C, a boiling point of 256.1°C, and is practically insoluble in water.
Biphenyl is stable in water under most temperature, pH, and light conditions.
The acute oral LD50 for biphenyl for rats is 3280 mg/kg. Prolonged exposure
to biphenyl vapors should be avoided (22).
Ill
0-phenylphenol (IV) is used as a-disinfectant and fungicide. The CAS
registry number for o-phenylphenol is 90-43-7, and it is commonly referred
to as 2-phenylphenol, biphenyl-2-ol, 2-hydroxybiphenyl, (1,1'-biphenyl)-2-ol,
and 2-biphenylol. 0-phenylphenol forms colorless to pinkish crystals, has
a melting point of 57 °C, a boiling point of 286 °C, and its water solubility
is 0.7 g/kg at 25°C. 0-phenylphenol is stable in water under most temperature,
pH, and light conditions. The acute oral L050 for o-phenylphenol for rats is
2480 mg/kg (23).
IV
An analysis method for determination of biphenyl and o-phenylphenol in
produce has been reported (24). Produce samples are extracted by homogenizing
them in acetone, and then by partitioning the homogenate with petroleum ether
15
-------
and methylene chloride. An adsorption chromatography cleanup procedure using
Florisil was described; quantitative recoveries of biphenyl and o-phenylphenol
were reported using this cleanup technique. Biphenyl and o-phenylphenol quanti-
fications were done by packed column GC usinq a flame ionization detector (FID).
A method to determine biphenyl in seawater has also been reported (25).
Bipnenyl was extracted from the seawater by equilibration with hexane or
carbon tetrachloride in a separatory funnel. An adsorption chromatography
cleanup procedure using silica gel or alumina was described. Analysis of
biphenyl was done by capillary column GC-FID. Analysis methods using reverse-
phase column HPLC-fluorescence, similar to the method evaluated, have also been
reported (12.19).
The method provided by the Project Officer for evaluation for determination
of biphenyl and o-phenylphenol in wastewaters consisted of extraction with
methylene chloride in a separatory funnel; drying of the methylene chloride
extracts over anhydrous sodium sulfate; solvent exchange to acetonitrile;
concentration of the extract to 2.5 ml using Kuderna-Danish (K-D) techniques;
and analysis of the extract by HPLC using reverse-phase conditions and a UV
detector. The method included no cleanup procedure.
CONCLUSIONS
An analysis method designed to determine biphenyl and o-phenylphenol in
wastewater was found to be marginally acceptable. The method was applied to
reagent water and Columbus POTW effluent samples spiked at the 2.5 or 25 vg/L
levels with biphenyl and o-phenylphenol. Recoveries of biphenyl and o-phenyl-
phenol ranged from 51 to 82 percent; recoveries were not matrix-dependent.
Losses may have been due to the rigorous conditions needed to concentrate
the sample because of the use of acetonitrile as the solvent. The HPLC-UV
conditions used for sample analyses yielded acceptable chromatography,
sensitivity, and selectivity.
EXPERIMENTAL
The following procedure was outlined in the biphenyl and o-phenylphenol
analysis method:
1. Place sample (approximately 1 liter) into a 2-liter
separatory funnel and extract the sample with three
60-mL portions of methylene chloride. Combine the
extracts.
2. The combined extracts are dried by pouring through a
chromatographic column containing 10 cm of anhydrous
sodium sulfate.
3. Concentrate the combined extracts to an apparent volume
of 5 ml using K-D equipment with the water bath at
90 to 95 °C.
16
-------
4. "Exchange the solvent to acetonitrlle by adding
50 ml of acetonitrile to the extract in the K-D
apparatus and concentrating as described above to
1 ml. Adjust the sample extract volume to
2.5 ml by addition of 1.5 mL of water.
5. Analyze the sample by HPIC-UV using the following
conditions:
- reverse-phase column, 2.6 mm ID by 250 mm long;
- 10 micron Perkin-Elmer HC-ODS Sil-X;
- Isocratic elution for 5 minutes using 40 percent
acetonitrile in water, then linear gradient elution
to 100 percent acetonitrile over 25 minutes;
- flow rate of 0.5 mL/min;
- 50 vL injection volume;
• UV detector at 254 nm.
Samples processed included the following:
1. Triplicate reagent water samples. Reagent water was
obtained from a Millipore system.
2. Triplicate reagent water samples spiked with biphenyl
and o-phenylphenol at the 2.5 vg/L concentration level.
3. Triplicate reagent water samples spiked with biphenyl
and o-phenylphenol at the 25 pg/L concentration level.
4. Triplicate POTW secondary effluent samples. POTW
secondary effluent was obtained from the City of Columbus.
5. Triplicate POTW secondary effluent samples spiked with
biphenyl and o-phenylphenol at the 2.5 vg/L concentration
level.
6. Triplicate POTW secondary effluent samples spiked with
biphenyl and o-phenylphenol at the 25 vg/L concentration
level.
The method EDLs, defined as the concentration of biphenyl and o-phenyl-
phenol in a sample yielding a S/N of 5, were determined by injecting 0.01 and
0.05 v9/mL solutions of biphenyl and o-phenylphenol in HPLC mobile phase,
respectively.
QUALITY ASSURANCE
Instrumentation was set up as described in the method. Sensitivity
achieved was approximately equivalent to that reported in the method.
Calibration standards were prepared containing biphenyl and o-phenylphenol
at the 1.0, 10, and 50 ug/mL concentration levels in HPLC mobile phase.
These are equivalent to biphenyl and o-phenylphenol concentrations of 2.5,
17
-------
25, and 125 yg/L in a water sample. These calibration standards were analyzed
In duplicate prior to analyses of the water extracts; a calibration standard
was analyzed after every five water extracts. Response factors were
calculated for each calibration run by dividing the concentration level in
pg/L by the corresponding peak area. Resultant calibration data are reported
in Table 6. Response factors were repeatable over the entire calibration
range. Response factors of 0.00073 and 0.00016 were used for calculations
of biphenyl and o-phenylphenol concentrations in the water extracts,
respectively.
TABLE 6. BIPHENYL AND 0-PHENYLPHENOL CALIBRATION DATA
Compound
Biphenyl
Biphenyl
Biphenyl
O-phenyl phenol
O-phenyl phenol
O-phenyl phenol
Concen-
tration
Vg/Lla)
2.5
25
125
2.5
25
125
Average
Peak
Area
3520
33700
166000
1600
15800
79100
Percent
Standard
Deviation
1
5
1
8
1
2
Number of
Replicates
3
4
4
3
4
4
Average
Response
Factors
0.00071
0.00074
0.00075
0.0016
0.0016
0.0016
(a) Equivalent concentration of compound in water sample.
Standards of biphenyl and o-phenylphenol were obtained from two independent
sources. Calibration standards used for quantification of biphenyl and o-phenyl-
phenol in the water samples were prepared from compounds obtained from the
reference standards repository of EPA-HERL. A test calibration standard was
prepared at the 10 pg/mL concentration level using biphenyl and o-phenylphenol
from a chemical supply house. This test calibration standard was analyzed in
triplicate and the resultant peak areas were compared to those generated from
analyses of the original calibration standards, for both compounds, the
average peak area generated from the test calibration standard varied by less
than six percent from the peak areas generated from the original calibration
solutions.
RESULTS AND DISCUSSION
Recoveries of biphenyl and o-phenylphenol from reagent water and POTW
effluent were generally less than 80 percent. These recovery data are given
in Table 7. The cause of these low recoveries is not evident. The extraction
procedure used should provide efficient removal of these two compounds from
the water samples. The conditions required to concentrate the samples to
18
-------
TABLE 7. RECOVERIES OF BIPHENYl AND 0-PHENYLPHENOL FROM WATER*3*
Compound
Blphenyl
Biphenyl
Biphenyl
Blphenyl
0-phenyl phenol
0-phenyl phenol
0-phenyl phenol
0-phenyl phenol
Spike
Level ,
vg/l
2.5
25
2.5
25
5.0
50
5.0
50
Matr1x(b)
1
1
2
2
1
1
2
2
Blank
Level ,
vg/l
0.20
0.20
0.90
0.90
MOW
NO
NO
NO
Percent, *
Recoveryv '
74
51
56
61
73
60
69
82
Standard
Deviation, X
2
11
4
1
4
5
2
« f
15
(a) Recovery data are averages of three replicate analyses.
(b) l=Reagent water; 2=Columbus POTW secondary effluent.
(c) Corrected for blank level.
(d) ND=not detected.
2.5 mL after addition of acetonitrile are rigorous. The high bath temperatures
necessary for K-D concentrations may contribute to the loss of these compounds.
A pH adjustment step was not included in the method. Reagent water and POTW
effluent samples used were generally In a pH range of 5-6. A lower pH might
Increase recoveries of o-phenylphenol by increasing its extraction efficiency
from water.
Both reagent water and POTW effluent samples contained low levels, 0.2 to
0.9 ug/L, of biphenyl or a compound eluting at the same time as biphenyl.
These interferences did not complicate the determination of biphenyl in the
samples. 0-phenylphenol was not detected in any of the unspiked samples.
Examples of chromatograms obtained from reagent water and POTW secondary
effluent samples unspiked and spiked at the 2.5 pg/L level are given in
Figures 5 and 6.
The method EDLs were determined by analyzing 0.01 and 0.05 vg/mL
solutions of biphenyl and o-phenylphenol in HPLC mobile, respectively; the
resultant chromatograms are shown in Figures 7 and 8. These solutions
yielded S/Ns of 14 and 9.3, respectively. The EOLs for biphenyl and o-phenyl-
phenol were determined to be 0.04 and 0.01 yg/L, respectively. These EOLs
were significantly lower than the EDLs of 0.25 and 0.5 yg/L reported in the
method for biphenyl and o-phenylphenol, respectively.
19
-------
(a)
7.0 9.0 11.0 13.0 15.0 17.0 19.0 21.0 23.0 25.0
Retention Time, min.
Biphenyl-
0-phenylphenol
(b)
I ' • • ' 1
7.0 9.0 11.0 13.0 15.0 17.0 19.0 21.0 23.0 25.0
Retention Time, min.
FIGURE 5. HPLC-UV CHROMATOGRAMS OF (a) REAGLNT WATER AND (b) REAGENT
WATER SPIKED WITH BIPHENYL AND 0-PHENYLPHENOL AT THE
2.5 uq/L LEVEL.
20
-------
(a)
7.0 9-0 11.0 13.0 15.0 17.0 19.0 21.0 23.0 25.0
Retention Time, min.
Biphenyl
0-phenylphenol
(b)
7.0 9.0 11.0 13.0 15.0 17.0 19.0 21.0 23.0 25.0
Retention Time, min.
FIGURE 6. HPLC-UV CHROMATOGRAMS OF (a)POTW EFFLUENT AND (b) POTW
EFFLUENT SPIKED WITH BIPHENYL AND 0-PHENYLPHENOL AT THE
2.5 pq/L LEVEL.
21
-------
PO
EDL * 0.125 vg/L x M? x 5 s °-04 ^9/L
24.5 25.0 25.5 26.0 26.5 27.0 27.5 28.0 28.5 29.0
Retention Time, min.
FIGURE 7. HPLC-UV CHROMATOGRAM OF A BIPHENYL STANDARD EQUIVALENT TO 0.125 ug/L IN WATER
USED TO DETERMINE METHOD EDL.
-------
EDL « 0.025 yg/L x £S x 5 « 0.01 v9/L
6.6 7.2 7.8 8.4 9.0 9.6 10.2 10.8 11.4 12.0
Retention Time, m1n.
FIGURE 8. HPLC-UV CHROMATOGRAM OF AN 0-PHENYLPHENOL STANDARD EQUIVALENT TO
0.025 pg/L IN WATER USED TO DETERMINE METHOD EDL.
-------
RECOMMENDATIONS
It is possible that the low recoveries of biphenyl and o-phenylphenol
may have resulted from problems encountered during the extraction and/or
concentration steps of the analysis method. Further study is warranted to
improve the recoveries of these two compounds from water. Studies should be
directed towards optimizing the extraction conditions, perhaps by adjusting
the sample pH or by using extraction procedures that are more easily controlled
than the use of separator^ funnels. A suggested alternative is to tumble the
water/methylene chloride mixture for a prescribed amount of time. The concen-
tration conditions should also be changed so that they are not so rigorous.
This might be done by solvent exchange to a lower-boiling solvent than
acetonitrile, or using a concentration apparatus other than K-D equipment.
24
-------
SECTION 4
ANALYSIS OF BENTAZON IN WASTEWATER
BY LIQUID CHROMATOGRAPHY
INTRODUCTION
Bentazon (V) is used as a contact herbicide. The IUPAC name for bentazon
is 3-isopropyl-(lH)-benzo-2,l,3-thiadiazin-4-one-2,2-dioxide, and Us CAS
registry number is 25057-89-0. Common synonyms for bentazon include BAS 351H,
Basagran, Bentazone, and Bendioxide. Bentazon is a colorless crystalline
powder with a melting point of 137-139°C. Bentazon has a solubility in water
of 500 mg/kg at 20°C. The acute oral LD50 for rats for bentazon is 1100 mg/kg
(26).
Methods have been reported for the determination of bentazon in soil
(27,28). The soil sample was shaken with a mixture of acetonitrile, water,
and methanol; the extracted bentazon was derivatized with diazomethane and
analyzed by GC-ECD. Other GC methods have been reported (29). A reverse-
phase HPLr-UV analysis method similar to the method validated has also been
reported (30). Literature references indicate that bentazon may decompose
when exposed to light (29). No cleanup methods were reported.
The method provided by the Project Officer for evaluation for determination
of bentazon in wastewaters consisted of adjustment of the sample pH by the
addition of sodium hydroxide; addition of sodium chloride to t*» sample;
extraction of the sample with methylene chloride using a separator> funnel;
back extraction of the methylene chloride extract with 0.1 M NaOH; and
adjustment of the sample volume to 5 ml with acetate buffer.
25
-------
CONCLUSIONS
An analysis method designed to determine bentazon in wastewaters was
found to be acceptable. The method was applied to reagent water and Columbus
POTW effluent samples spiked at the 10 and 100 ug/L levels with bentazon.
Recoveries of bentazon from all of the samples were greater than 76 percent.
The HPLC-UV conditions used for sample analyses yielded acceptable chromatography,
sensitivity, and selectivity.
EXPERIMENTAL
The following procedure was outlined in the bentazon analysis method:
1. Place sample (approximately 1 liter) into a 2-liter
separatory funnel; add 35 mg/L of sodium thiosulfate
per ppm of free chlorine; adjust the pH of the sample
to within the range of 2.5 to 3.5 with dilute sodium
hydroxide or suIfuric acid; and add 200 grams of
sodium chloride.
2. Extract the sample with three 60-mL portions of
methylene chloride, combining the extracts in a
250-mL separatory funnel.
3. Extract the methylene chloride extract with two 2-mL
aliquots of 0.1 M NaOH in HPLC water and transfer the
aqueous layers to a 5-mL volumetric flask.
4. Add two drops of glacial acetic acid to the volumetric
flask and dilute to volume with acetate buffer solution.
5. Analyze the sample by HPLC with UV detection using the
following conditions:
- reverse-phase Ultrasphere ODS, 4.6 mm ID by 250 mm
column;
- isocratic 35 percent methanol/65 percent buffer
(pH 4.7) mobile phase;
- flow rate of 2.0 mL/min;
- injection volume of 100 wL;
- UV detector wavelength set at 340 nm.
No modifications were made in this method. The HPLC column particle size
was not specified in the method. In consultation with the EPA Task Officer,
prior to method evaluation, it was specified that a 5 micron Ultrasphere ODS
column should be used.
Samples processed included the following:
1. Triplicate reagent water samples. Reagent water
was obtained from a Millipore system.
26
-------
2. Triplicate reagent water samples spiked with bentazon
at the 10 pg/L concentration level.
3. Triplicate reagent water samples spiked with bentazon
at the 100 pg/L concentration level.
4. Triplicate POTW secondary effluent samples. POTW
secondary effluent was obtained from the City of Columbus.
5. Triplicate POTW secondary effluent samples spiked with
bentazon at the 10 pg/L concentration level.
6. Triplicate POTW secondary effluent samples spiked with
bentazon at the 100 pg/L concentration level.
Recoveries were determined by comparison to standard solutions of bentazon
prepared at the 1, 5, and 50 vg/mL concentration levels in HPLC mobile oha^e.
These concentration levels were equivalent to 5, 25, and 250 pg/L of bentazon
in the original samples assuming a final extract volume of 5 ml_. Response
factors were calculated for the standards and used to determine concentration
levels in the a^ovementioned reagent water and POTW effluent samples.
The EDL for bentazon, defined as the concentration of bentazon in a
sample yielding a S/N of 5, was determined by injecting a 0.1 pg/tnL standard
solution of bentazon prepared in HPLC mobile phase. The solution was equivalent
to a bentazon concentration of 0.5 pg/L in a water sample.
QUALITY ASSURANCE
Instrumentation was set up as described in the method. Sensitivity
achieved was approximately equivalent to that reported in the method.
Calibration standards consisted of bentazon solutions prepared at the 1, 5,
and 25 pg/mL concentration levels in HPLC mobile phase. Each calibration
standard was analyzed in duplicate prior to analysis of any evaluation
samples. A selected calibration standard was then analyzed after every five
evaluation samples. Response factors were calculated for each calibration
run by dividing the equivalent bentazon concentration level in the sample
in pg/L by the bentazon peak area. Resultant calibration data -ire reported
in Table 8. Response factors were reproducible over the entire calibration
range. A response factor of 0.10 was used for calculations of bentazon
concentrations in the evaluation samples.
Standards of bentazon were obtained from two independent sources.
Bentazon from the reference standards repository of the EPA-HERL was used
for preparation of calibration standards as well as for preparation of the
evaluation samples. A test calibration standard was also prepared at the
5 pg/L concentration level from bentazon from a chemical supply house. The
peak area resulting from the analysis of the test calibration standard was
less than two percent lower than tl average peak area obtained from analyses
of the equivalent EPA-HERL calibrat.on standard indicating that the standards
obtained were probably within two percent of their specified purities.
27
-------
TABLE 8. BENTAZON CALIBRATION DATA
Concentration,
vg/Lia)
5.0
25
250
Average
Peak
Area
52.4
224
2490
Standard
Deviation
1.34
1.66
2.23
Number of
Replicates
3
3
4
Average
Response
Factors
0.10
0.11
0.10
(a) Equivalent concentration of bentazon in water sample.
RESULTS AND DISCUSSION
Bentazon was not detected in unspiked reagent water or POTW effluent
samples. The chromatograms obtained from reagent water and POTW effluent
blanks did not contain any other peaks resulting from interferences. This
was unexpected since the use of UV detectors usually results In some evidence
of interferences from the sample matrix. Apparently the basic backextraction
step specified in the extraction procedure removes any potential interferences
in the matrices used for this evaluation. Recoveries of bentazon from both
reagent water and POTH effluent were greater than 92 percent at the 10 ug/L
spike level. Recoveries were slightly lower from both samples at the 100 ug/L
level, ranging from 76 to 81 percent. Since spiked water samples were prepared
using the same stock standards, it is not expected that the recovery differences
between the two spike levels are due to errors during sample preparation.
Bentazon recovery data are given in Table 9. Examples of chromatograms
obtained from the analyses of aliquots of POTW effluent unspiked and spiked
with bentazon at the 10 pg/L level are shown in Figure 9.
The EDL for bentazon was determined by analyzing a 0.1 vg/ml standard
solution of bentazon in HPLC mobile phase; the resultant chromatogram is
shown in Figure 10. This solution yielded a S/N of 2.3. The EDL was
calculated to be 1.1 ug/L of bentazon, which is the same value reported in
the method. The EDL does n.n take into account any interferences or recovery
losses that might be encountered from a particular matrix.
28
-------
(a)
21 22 23 24 25 26 27 28 29
Retention Time, min.
30
Bentazon
(b)
21 22 23 24 25 26 27 28 29 30
Retention Time, min.
FIGURE 9. HPLC-UV CHROMATOGRAM OF (a) UNSPIKED POTW EFFLUENT,
AND (b) POTW EFFLUENT SPIKED WITH BENTAZON AT THE
10 yg/L LEVEL
29
-------
EOL - 0.5 yg/L X 57757 X 5-1.1 uq/L
00
o
-r-t-t-f-i-t-f t-f i—t- »'t"Ti t-ft |-» i-t--« ft-fr f | i-t t-r-f t-r-r-t fT-t-
18.7 19.4 20.1 20.8 21.5 22.2 22.9 23.6 24.3 25.0
Retention Time, m1n.
FIGURE 10. HPLC-UV CHROMATOGRAM OF A BENTAZON STANDARD EQUIVALENT TO 0.5 wg/L IN WATER
USED FOR EDL DETERMINATION
-------
TABLE 9. RECOVERIES OF BENTAZON FROM HATER
Spike
Level .
pg/L
10
100
10
100
Matrix ^
1
1
2
2
Blank
Level ,
pg/L
ND
ND
NO
NO
Percent. *
Recovery1 '
92
81
94
76
Standard
Deviation , %
2
10
7
2
(a) l=Re-»gent water; 2=Columbus POTW secondary effluent.
(b) ND=not detected.
(c) Recovery data are averages of three replicate analyses.
RECOMMENDATIONS
The method was acceptable for determination of bentazon in reagent water
and POTW effluents. Lower recoveries were observed at the 100 yg/L bentazon
spike levels than were observed at the 10 pg/L bentazon spike levels. Although
this might have been caused by spiking irregularities, this is not thought to
be the case. The solubility of bentazon in water at 20°C is approximately
500 pg/mL. The concentration of bentazon in the final extract derived from
a one-liter sample of water spiked at the 20 ug/L level is 100 ug/mL. This
concentration level is not close to the solubility limits of bentazon in
water; recovery losses were most likely not due to precipitation of bentazon
from the sample.
31
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SECTION 5
ANALYSIS OF CARBAMATE AND AMIDE PESTICIDES IN WASTEWATER
BY LIQUID CHROMATOGRAPHY
INTRODUCTION
Pesticides Included In the method evaluated were carbaryl, napropamide,
propanil and vacor. A standard of vacor could not be obtained; the method
was not evaluated for vacor.
Carbaryl (VI) 1s a contact Insecticide with slight systemic properties.
The IUPAC name for carbaryl is 1-naphthyl methylcarbamate and Its CAS
registry number Is 63-25-2. A common synonym for carbaryl Is Sevin.
Carbaryl is a colorless crystalline solid with a melting point of 1429C.
Carbaryl has a solubility in water of 120 mg/L at 30°C; It is soluble in
most polar organic solvents. Carbaryl is stable to light, leat and hydroly-
sis under normal storage conditions. The acute oral LD50 •'• r male rats for
carbaryl is 850 mg/kg (31).
VI
Napropamide (VII) is an herbicide. The IUPAC name for napropamide is
N,N-diethyl-2-(l-naphthyloxy)propionamide and its CAS registry number is
15299-99-7. A common synonym for napropamide is Devrinol. Napropamide is
VII
32
-------
a brown solid with a melting point of 74.8-75.5°C. Napropamide has a solu-
bility in water of 73 mg/L at 20eC and is very soluble in acetone, ethanol,
and xylene. The acute oral LD50 for rats for napropamide is >5000 mg/kg (32).
Propanil (VIII) is a contact herbicide. The IUPAC name for propanil is
3',4'-dichloroprop1onanilide and its CAS registry number is 709-98-8. Common
synonyms for propanil include Stam F-34, Surcopur, and Rogue. Propanil is a
colorless solid with a melting point of 92-93°C. Propanil has a solubility
1n water of 225 mg/L at 25°C. Propanil is hydrolyzed in acid and alkaline
media to 3,4-dichloroaniline and propionic acid. The acute oral LD50 for
rats for propanil is 1285-1483 mg/kg
VIII
Analysis methods for the determination of carbaryl, napropamide, and
propanil in produce samples have been reported in the literature. These
methods usually involve the use of reverse-phase column HPLC coupled with
a UV or fluorescence detector (19,30,33,34,35). Several analysis methods
using packed or capillary column GC, usually with an electron capture
detector, are also reported (2",36,37,38,39).
The method provided by the Project Officer for evaluation for determination
of carbamate and amide pesticides consisted of addition of NaCl to the sample;
adjustment of the sample pH by addition of dilute sodium hydroxide or sulfuric
acid; extraction of the sample with methylene chloride using a separatory
funnel; drying of the sample using anhydrous sodium sulfate; concentration of
the sample to 10 ml after solvent substitution with HPLC mobile phase; and
analysis of the sample extract by reverse phase HPLC using a UV detector.
CONCLUSIONS
A method designed to determine carbamate and amide pesticides in waste-
waters was evaluated. The method was found to be acceptable when applied to
two of the compounds, napropamide and propanil. The method was not acceptable
for the determination of carbaryl in wastewater. The instrumentation yielded
sufficient sensitivity to determine low ug/L levels of all three compounds in
a water matrix. Recoveries of napropamide and propanil from water were
generally greater than 80 percent. However, recoveries of carbaryl were
generally lower than 50 percent and were matrix and concentration dependent.
33
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EXPERIMENTAL
The following procedure was outlined in the carbamate and amide analysis
method:
1. Place sample (approximately 1 liter) Into a 2-liter
separatory funnel; add 200 g sodium chloride to the
sample; and adjust the pH of the sample to within the
range of 6.5 to 7.5 with dilute sodium hydroxide or
sulfuric acid.
2. Extract the sample with three 60-mL portions of
methylene chloride, combining the extracts.
3. Dry the combined extracts by pouring through a
chromatographic column containing 10 cm of anhydrous
sodium sulfate.
4. Concentrate the combined extracts to an apparent volume
of 1 ml using a rotating evaporator with the water bath
temperature between 35 and 40°C.
5. Add 15 mL of acetonitrile to the sample and reconcentrate
to an apparent volume of 1 ml using the rotating evaporator.
6. Adjust sample volume to 10 ml with 50:50 acetonUrile:water.
7. Analyze the sample by HPLC-UV using the following conditions:
- reverse-phase column, 4 mm ID by 250 mm long;
- 5 micron Ultrasphere ODS;
- linear gradient elution from 40 percent acetonitrile
1n water to 65 percent acetonitrile in water over
10 minutes;
- flow rate of 1 mL/min;
- 100 pL injection volume;
- UV detector at 254 nm.
Samples processed included the following:
1. Triplicate reagent water samples. Reagent water was
obtained from a Millipore system.
2. Triplicate reagent water samples spiked with carbaryl,
napropamide, and propanil at the 2.0, 6.0, and 0.2 pg/L
concentration levels, respectively.
3. Triplicate reagent water samples spiked with carbaryl,
napropamide, and propanil at the 20, 60, and 2.0 ug/L
concentration levels, respectively.
4. Triplicate POTW secondary effluent samples. POTW secondary
effluent was obtained from the City of Columbus.
34
-------
5. Triplicate POTW secondary effluent samples spiked with
carbaryl, napropamide, and propanil at the 2.0, 6.0, and
0.2 pg/L concentration levels, respectively.
6. Triplicate POTW secondary effluent samples spiked with
carbaryl, napropamide, and propanil at the 20, 60, and
2.0 ug/L concentration levels, respectively.
Recoveries were determined by comparison to standard solutions of carbaryl
and napropamide prepared at the 0.1, 1.0, and 10 vig/mL concentration levels
and propanll at the 0.01, 0.05, and 0.2 vg/ml concentration levels in HPLC
mobile phase. These concentration levels were equivalent to 1.0, 10, and
100 vsfL of carbaryl and napropamide, and 0.1, 0.5, and 2.0 v9/L of propanil
in the original samples assuming a final extract volume of 10 ml. Response
factors were calculated for the standards and used to determine concentration
levels in the abovementioned reagent water and POTW effluent samples.
The method EDLs, defined as the concentrations of carbamate and amide
pesticides in a sample yielding a S/N of 5, were determined by injecting
0.05, 0.005, and 0.5 ug/L solutions of carbaryl, napropamide, and propanil
in HPLC mobile phase, respectively.
QUALITY ASSURANCE
Instrumentation was set up as described in the method. Sensitivity
achieved was approximately equivalent to that reported in the method. Cali-
bration standards were prepared containing carbaryl and napropamide at the
0.1, 1.0, and 10 ug/mL concentration levels and propanil at the Q.01, 0.05,
and 0.2 vg/ml concentration levels in HPLC mobile phase. These are equivalent
to carbaryl and napropamide concentrations of 1.0, 10, and 100 vg/L and
propanil concentrations of 0.1, 0.5, and 2.0 yg/L in a water sample. These
calibration standards were a.ialyzed in duplicate prior to analyses of the
water extracts; a calibration standard was analyzed after every five water
extracts. Response factors were calculated for each calibration run by
dividing the concentration level in ug/L by the corresponding peak area.
Resultant calibration data are reported in Table 10. Response factors were
repeatable over the entire calibration range. Response factors of 0.10, 0.17,
and 0.018 were used for calculations of carbaryl, napropamide, and propanil
concentrations in the water extracts, respectively.
Standards of carbaryl, napropamide, and propanil were obtained from two
Independent sources. Calibration standards used for quantification of these
compounds in the water samples were prepared from compounds obtained from the
reference standards repository of EPA-HERL. A test standard was prepared at
the 10 ug/mL concentration level for carbaryl and napropamide and at the
0.2 ug/mL concentration level for propanil in the HPLC mobile phase using
compounds obtained from a chemical supply house. This test calibration
standard was analyzed in duplicate and the resultant peak areas compared to
those generated from analyses of the original calibration standards. Resultant
data indicated that in all cases the standard obtained from the chemical supply
35
-------
TABLE 10. CARBARYL, NAPROPAHIDE, AND PROPANIL CALIBRATION DATA
Compound
Carbaryl
Carbaryl
Carbaryl
Napropamide
Napropamide
Napropamide
Propanil
Propanil
Propanil
Concen-
tration,
1.0
10
100
1.0
10
100
0.1
0.5
2.0
Average
Peak
Area
5.3
50.9
517
6.1
57.0
570
5.5
32.8
102
Standard
Deviation
23
4
1
13
8
1
6
8
2
Number of
Replicates
2
4
4
2
3
4
2
4
4
Average
Response
Factors
0.19
0.20
0.19
0.16
0.18
0.18
0.018
0.015
0.020
(a) Equivalent concentration of compound in water sample.
house was not as pure as that obtained from the reference standards repository.
Peak areas obtained from the test calibration standards of carbaryl, napropamide,
and propanil were 36 percent, 18 percent, and 12 percent lower than those
obtained from the original calibration standards, respectively.
RESULTS AND DISCUSSION
Recoveries of carbaryl from reagent water and POTW effluent were low.
Recoveries of carbaryl were lower from water spiked at the 2 v9/L level than
from water spiked at the 20 pg/L level. Recoveries of carbaryl from POTW
effluent were lower than that from reaqent water spiked at the same concen-
tration levels. Recoveries of napropamide and propanil were generally
greater than 80 percent from both reagent water and POTW effluent, regardless
of the cortipound concentration level. These recovery data are given in
Table 11. Examples of chromatograms obtained from the HPLC analyses of
unspiked and spiked reagent water and POTW effluent samples are shown in
Figures 11 and 12. The cause of the low carbaryl recoveries is not evident.
Two sources of recovery losses can be examined: carbaryl may not be efficiently
extracted from the water into the methylene chloride during the extraction
procedure and/or carbaryl may be lost during the concentration step.
POTW effluent samples contained low levels of napropamide and propanil
or compounds eluting at the same times. These napropamide and propanil
interferences were present at the 1.7 and 0.06 ug/L levels, respectively.
These interferences did not complicate the determination of napropamide or
propanil in the samples. Carbaryl was not detected in the unspiked POTW
effluent. No interferences were detected in the reagent water.
36
-------
TABLE 11. RECOVERIES OF CARBARYL, NAPROPAMIDE,
AND PROPANIL FROM WATER(c)
Compound
Carbaryl
Carbaryl
Carbaryl
Carbaryl
Kapropamide
Napropamide
Napropamide
Napropamide
Propanil
Propanil
Propanil
Propanil
Spike
Level ,
ug/L
2.0
20
2.0
20
6.0
60
6.0
60
0.2
2.0
0.2
2.0
Matrix*3*
1
1
2
2
1
1
2
2
1
1
2
2
Blank
Level ,
pg/L
ND
NO
ND
ND
ND
ND
1.7
1.7
ND
ND
0.06
0.06
Percent(d)
Recovery1 '
52
83
ND
28
103
102
96
94
79
99
85
77
Standard
Deviation ,%
10
13
--
16
2
2
7
3
6
3
11
7
(a) l=Reagent water; 2=Columbus POTW secondary effluent.
(b) ND = not detected.
(c) Recovery data are averages of three replicate analyses.
The HPLC-UV system was approximately ten times less sensitive for carbaryl
than stated in the method. System sensitivity for propanil and napropamide was
approximately equal to that listed in the method. The method EDLs were deter-
mined by injecting 0.05, 0.005, and 0.05 pg/mL solutions of carbaryl,
napropamide, and propanil in HPLC mobile phase, respectively; resultant
chromatograms are shown in Figures 13-15. These carbaryl, napropamide, and
propanil solutions yielded S/Ns of 2.1, 13, and 8.3, respectively. The EDLs
for carbaryl, napropamide, and propanil were determined to be 1.2, 0.02, and
0.3 pg/L, respectively.
RECOMMENDATIONS
The analysis method was acceptable for the determination of napropamide
and propanil in reagent water and POTW effluents. Recoveries of carbaryl,
however, were low enough to warrant further examination of the method as
applied to carbaryl; possibly carbaryl should be removed from the method.
Carbaryl is more polar than napropamide and propanil and is most likely not
as efficiently removed from water into methylene chloride. The use of a
more polar extraction solvent, or perhaps more exhaustive extraction of the
water sample might increase carbaryl recoveries.
37
-------
(a)
9 10 13 14 15 16 17 18
Retention Time, mln
10 11 12 13 14 15
Retention Time, min
17 18
FIGURE 11. HPLC-UV CHROMATOGRAMS OF (a) REAGENT WATER, AND (b) REAGENT
'WATER SPIKED WITH THE CARBAMATE AND AMIDE PESTICIDES AT THE
2.0yg/L LEVEL.
38
-------
(a)
10 11 12 13 14 15 16 17 18
Retention Time, min
Cb)
Napropumide
10 II 12 13 14 15 16 17 18
Retention Time, min.
FIGURE 12. HPLC-UV CHROMATOGRAM OF (a) POTW EFFLUENT, AND (b) POTW
EFFLUENT SPIKED WITH THE CARBAMATE AND AMIDE PESTICIDES
AT THE 2.0 pg/L LEVEL.
39
-------
0.006 MV
EDL - 1.0 yg/L
5 - 0.1 pg/L
1.87 1.94 2.01 2.08 2.15 2.22 2.29 2.36 2.43 2.50
Retention Time, min.
FIGURE 34. GC-NPD CHROMATOGRAM OF LETHANE SOLUTION REPRESENTING 1.0 yg/L IN WATER
USED TO DETERMINE THE METHOD EDL.
-------
CD
tn
EDL - 1.0 pg/L x x 5 » 0.02 pg/L
0.006 MV
16.7 16.9 17.1 17.3 17.5 17.7 17.9 18.1 18.3 18.5
Retention Time, min.
FIGURE 35. GC-NPD CHROMATOGRAM OF NORFLURAZON SOLUTION REPRESENTING 1.0 pg/L
IN WATER USED TO DETERMINE METHOD EDL.
-------
EDL = 1.0 pg/L x x 5 = 0.5 pg/L
t— f-f|--fT-'t-t— • f»— •!••• r- -t- -|--i--i"- vf — » — f-r-t — ;• t • i •«— «- |- i f f--i
3.8 4.2 4.6
5.8 6.2
6.6 7.0
3.4
Retention Time, m1n.
FIGURE 36. GC-NPD CHROMATOGRAM OF FLURIDONE SOLUTION REPRESENTING 1.0 yg/L IN WATER
USED TO DETERMINE METHOD EDL.
-------
SECTION 9
ANALYSIS OF DINITRO AROMATIC PESTICIDES
IN WASTEWATER BY GAS CHROMATOGRAPHY
INTRODUCTION
Basalin (XX) is a preemergent herbicide. The IUPAC name for basalin is
N-2-chloroethyl-a,c»,a-trifluoro-2,6-dinitro-N-propyl-p-toluidine and its CAS
registry number is 33245-39-5. A common synonym for basalin is fluchoralin.
Basalin forms orange-yellow crystals with a melting point of 42-43°C. The
solubility of basalin in water is 70 mg/L at 20°C. The acute oral LD50 for
basalin for rats is 1110 mg/kg.
XX
CDNB (XXI) has an IUPAC name of l-chloro-2,4-dinitrobenzene and its CAS
registry number is 97-00-7. CDNB forms yellow crystals with a melting point
of 52-54°C. CDNB is practically insoluble in water and soluble in most
organic solvents. The acute oral LD50 for rats for CDNB is 1076 mg/kg.
XXI
87
-------
Dinocap Is a nonsystemic acaracide and contact fungicide. Dinocap Is a
mixture of 2,4-dinitro-6-octylphenyl crotonates (XXII) and 2,6-dinitro-4-
octylphenyl crotonates (XXIII) and its CAS registry number is 34300-45-3.
Dinocap is a dark brown liquid which is insoluble in water and soluble in
most organic solvents. The acute oral LD50 for rats for dinocap is 980-
1190 mg/kg (83).
CU3
CH
\
to-o/
^ \
CH3
nni
Several analyses methods for the determination of the dinitro aromatic
pesticides in various matrices have been reported. A method was reported for
the determination of dinocap in produce by GC-ECO (35). Methods were also
reported to determine basalin in formulations by GC-FID (84) and to determine
CDNB by HPLC (85).
The method provided by the Project Officer for evaluation for determination
of dim'tro aromatic pesticides consisted of adjustment of the sample pH to the
range of 5 to 9 by addition of dilute sodium hydroxide or sulfuric acid;
extraction of the sample with 15 percent methylene chloride in hexane using
a separatory funnel; drying of the sample using anhydrous sodium sulfate;
concentration of the sample to 1 ml after exchanging the solvent with hexane;
and analysis of the sample extract by packed column GC-ECD. A cleanup procedure
using Florisil was included in the method.
88
-------
CONCLUSIONS
A method designed to determine dinitro aromatic pesticides in wastewaters
was evaluated. The extraction, cleanup, and analysis portions of the metnod
were found to be acceptable for determination of basal in in reagent water and
POTW effluent and marginally acceptable for the determination cf CDNB and
dinocap in reagent water and POTW effluent. Recoveries of basalin spiked
into these matrices at the 0.1 and 1.0 yg/L levels were generally greater
than 90 percent both before and after the cleanup step. Recoveries of CDNB
and dinocap spiked into these matrices at the 0.1 and 1.0 pg/L levels were
generally greater than 70 percent both before and after the cleanup step.
EXPERIMENTAL
The following procedure was outlined in the dinitro aromatic pesticide
analysis method:
1. Place sample (approximately 1 liter) into a 2-liter
separatory funnel, and adjust the pH of the sample to
within the range of 5 to 9 with dilute sodium hydroxide
or sulfuric acid.
2. Extract the sample with three 60-mL portions of 15 percent
methylene chloride in hexane and combine the extracts.
3. Dry the combined extracts by pouring through a
chromatography column containing 10 cm of anhydrous
sodium sulfate.
4. Concentrate the combined extracts to 1 mL using K-D
equipment with the water bath at 90 to 95°C. A hexane
solvent exchange step is included.
5. A Florisil cleanup procedure is used for samples that
require cleanup. A specified amount of Florisil,
determined by its 1 auric acid value, is placed in a
chromatography column. The sample is applied to the
column in hexane, and the column is eluted with 30 mL
of 50 percent methylene chloride in hexane, which is
discarded. The column is then eluted with 30 mL of
methylene chloride (Fl) and 30 mL of 10 percent acetone
in methylene chloride (F2). Basalin and CDNB elute in
Fl, and dinocap elutes in F2. Each fraction is concentrated
to 1 mL using K-D equipment with the water bath at 80 to
85°C. A hexane solvent exchange step is included.
6. Analyze the sample by GC-ECD using the following conditions:
- 180 cm long by 2 mm ID glass column packed with
1.5 percent OV-17/1.95 percent OV-210 on Supelcoport
(100/120 mesh);
89
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- 5 percent methane/95 percent argon carrier gas at
33 ml/ml n flow rate;
- oven temperature of 160°C isothermal for basal in
and CDNB and 200° C isothermal for dinocap;
- injection volume of 5 vL.
These conditions were evaluated prior to analysis of water extracts, and
it was found that the dinitro aromatic pasticides eluted from the GC column
much later than specified in the analysis method. The method indicates that
basal in and CONB should elute at 6.4 and 2.0 minutes, respectively, and that
dinocap should elute from 10 to 16 minutes. Instead, dinocap eluted from
36 to 51 minutes, and basal in and CDN5 did not elute from the column. The
oven temperatures used for GC analysis of the samples were raised to 200°C
for basal in and CDII3, and to 230°C for dinocap. With the increased oven
temperatures, basal in c lutes at 4.8 minutes, CDNB elutes at 3.0 minutes, and
dinocap elutes between 11 and 15 minutes. Chroma tog rams showing the elution
profiles of basalin and ONB at 170°C and 2CO°C are given in Figure 37.
Chromatograms showing the elution profiles of dinocap at 200°C and 230°C
are given in Figure 38.
The EDLs for ^e dinitro aromatic pesticides originally listed in the
method were 1.0 vg/L for all three compounds. This was estimated to be too
high; EDLs of 0.01 ug/L were considered to be more likely. After consulta-
tion with the EPA Task Officer, it was agreed that method evaluations would
be done using compound spike levels of 0.1 and 1.0 vg/l.
Samples processed included the following:
1. Triplicate reagent water samples. Reagent water was
obtained from a Mi Hi pore system.
2. Triplicate reagent water samples spiked with the dinitro
aromatic pesticides at the 0.1 pg/L concentration level.
3. Triplicate reagent water samples spiked v/ith the dinitro
aromatic pesticides at the l.Oyg/L concentration level.
4. Triplicate POTW secondary effluent samples. POTH secondary
effluent was obtained from the City of Columbus.
5. Triplicate POTW secondary effluent samples spiked with the
dinitro aromatic pesticioes at the 0.1 vg/L concentration level.
6. Triplicate POTW secondary effluent samples spiked with the
dinitro aromatic pesticides at the 1.0 vg/L concentration level.
All extracts described in points 1-6 were analyzed and then treated to
Florisil cleanup procedure and reanalyzed by GC-ECO.
90
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(a)
CDNB
Basalin
2:0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Retention Time, min.
CDNB
(b)
Basalin
2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Retention Time, min.
FIGURE 37. GC-ECD CHROMATOGRAMS OF HEXANE SOLUTION CONTAINING BASALIN
AND CDNB USING OVEN TEMPERATURES OF (a) 170°C and (b) 200°C.
91
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5.5 11.0 16.5 22.0 27.5 33.0 38.5 44.0 49.5 55.0
Retention Time, min.
(b)
5.5 11.0 16.5 22.0 27.5 33.0 38.5 44.0 49.5 55.0
Retention Time, min.
FIGURE 38. .GC-ECD CHROMATOGRAMS OF HEXANE SOLUTION CONTAINING DINOCAP
USING OVEN TEMPERATURES OF (a) 200°C and (b) 230°C.
92
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Recoveries were determined by comparison to standard solutions of
basal in and CDNB prepared at the 0.05, 0.1, and 1.0 ug/mL concentration
levels and dinocap prepared at the 0.1, 1.0 and 1.5 yg/mL levels in hexane.
These concentration levels were equivalent to 0.05, 0.1, and 1.0 pg/L of
basal in and CDNB and 0.1, 1.0, and 1.5 vg/L of dinocap in the original
samples assuming a final extract volume of 1 mL. Response factors were
calculated for the standards and used to determine concentration levels in
the abovementioned reagent water and POTW effluent samples.
The method EDLs, defined as the concentration of each dinitro aromatic
pesticide in a sample yielding a S/N of 5, were determined by injecting
0.0005 yg/mL standard solutions of basalin and CDNB and a 0.05 yg/mL standard
solution of dinocap prepared in hexane. The solutions were equivalent to
basalin and CDNB concentrations of 0.0005 yg/L and a dinocap concentration
of 0.05 ig/L in a water sample.
QUALITY ASSURANCE
Instrumentation was set up as described in the method. Sensitivity
achieved was approximately three orders of magnitude lower than that reported
in the method for basalin and CDNB and one order of magnitude lower than that
reported for dinocap. Calibration standards consisted of basalin and CDNB
solutions prepared at the 0.05, 0.1, and 1.0 yg/mL concentration levels and
dinocap solutions prepared at the 0.1,, 1.0, an:! 1.5 yg/mL concentration levels
in hexane. Each calibration standard was analyzed in duplicate prior to
analysis of any evaluation samples. A selected calibration standard was then
analyzed after every five evaluation samples. Response factors were calculated
for each calibration run by dividing the equivalent pesticide concentration
level in the sample in yg/L by the pesticide peak area. Resultant calibration
data are reported in Table 2C. Response factors were repeatable over the
entire calibration range for all three compounds. Response factors of 0.00022,
0.00012, and 0.0020 were used for calculating basalin, CDNB, and dinocap
recoveries, respectively. The response factor for dinocap was determined
by using only one of the isomer peaks.
Standards of basalin, CDNB, and dinocap were obtained from the reference
standards repository of EPA-HERL; a standard was also obtained for dinocap
from a chemical supply house. Second standards were not obtained for basalin
and CDNB; it was not possible to check the purity of the standards obtained
for basalin and CDNB from the reference standards repository. A 0.1 yg/mL
standard solution of dinocap in hexane was prepared from the dinocap standard
obtained from the chemical supply house; this solution was analyzed in
duplicate and compared to equivalent standard solutions prepared from the
dinocap obtained from the reference standards repository.
RESULTS AND DISCUSSION
The dinitro aromatic pesticides were not detected in unspiked reagent
water or POTW effluent samples. The chromatograms obtained from reagent
water and POTW effluent blanks contained other small peaks. The patterns
displayed by these peaks were similar regardless of the sample matrix. The
93
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TABLE 20. DINITRO AROMATIC PESTICIDES CALIBRATION DATA
Compound
Basalin
Basal in
Basalin
CDNB
CDNB
CDNB
Dinocap
Dinocap
Dinocap
Concentration,
iig/L(a)
0.05
0.1
1.0
0.05
n.i
1.0
0.1
1.0
1.5
Average
Peak
Area
222
528
3890
463
993
7260
50
476
789
Standard
Deviation,
%
12
10
5
4
5
2
22
7
4
Number of
Replicates
10
11
11
11
10
11
8
8
3
Average
Response
Factors
0.00023
0.00019
0.00026
0.00011
0.00010
0.00014
0.0020
0.0021
0.0019
(a) Equivalent concentration of compound in water sample.
peaks may have been introduced during sample preparation. The interference
peaks eluted in Fl of the Florisil cleanup. These peaks represented inter-
ferences in the low pg/L range and did not interfere with the determination
of basalin and CDNB. One unidentified peak eluted within the retention time
range of where the dinocap isomers eluted; quantification of dinocap was
therefore based on one of the isomer peaks as shown in Figure 43.
Recoveries of basalin from reagent water and POTW effluent samples,
before cleanup, were greater than 94 percent at both the 0.1 and 1.0 pg/L
concentration levels. Recovery of basalin from reagent water at the 0.1 pg/L
level was high, 138 percent; the reason for this high recovery was not apparent.
In most cases, recoveries of basalin from reagent water and POTW effluent
samples were not significantly changed when the Florisil cleanup procedure was
used. Recovery of basalin at the 0.1 pg/L concentration level from POTW
effluent dropped from 94 percent to 74 percent when the cleanup procedure was
used. The reason for this was not apparent. Chromatograms obtained from the
GC analyses of POTW effluent extracts, unspiked and spiked with basalin at
the 1.0 pg/L concentration level, are shown in Figure 39. The same extracts,
after Florisil cleanup, are shown in Figure 41. Basalin recovery data are
given i.i Table 21.
Recoveries of CDNB from reagent ^ater and POTW effluent samples were
generally low, ranging from 69 to 91 percent. Recoveries of CDNB were not
significantly changed when the Florisil cleanup step was used. Although
94
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(a)
Unidentified Peaks
0.6
1.2
2.4 3.0 3.6
Retention Time, min.
4.S2
5.4 6.0
CDNB
Unidentified
Peaks .
(b)
Basal in
0.6 1.2 1.8 2.4 3.0 3.6
Retention Time, min.
4.2 4.8 5.4
6.0
FIGURE 39. GC-ECD CHROMAICGRAM OF (a) POTW EFFLUENT AND (b) POTW EFFLUENT
SPIKED WITH BASALIN AND CDNB AT THE 1.0 ug/L LEVEL, BEFORE CLEANUP.
95
-------
(a)
Unidentified Peaks
8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0
Retention Time, min.
Unidentified
Peak v
(b)
Dinocap peak used for
for quantification
8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0
Retention Time, min.
FIGURE 40. GC-ECD CHROMATOGRAM OF (a) POTW EFFLUENT, AND (b) POTW
EFFLUENT SPIKED WITH DINOCAP AT THE 1.0 ug/L LEVEL, BEFORE
CLEANUP.
96
-------
(a)
Unidentified Peaks
A
0.6 1.2 1.8 2.4 3.0 3.6
Retention Time, min.
4.2 4.8 5.4 6.0
0.6
1.2
1.8 2.4 3.0 3.6
4.2
4.8 5.4 6.0
Retention Time, min.
FIGURE 41. GC-ECD CHROMATOGRAM OF (a) POTW EFFLUENT AND (b) POTW
EFFLUENT SPIKED WITH BASALIN AT THE 1.0 pg/L LEVEL, AFTER
FLORISIL CLEANUP.
97
-------
(a)
0.6 1.2 1.8 2.4 3.0 3.6 4.2 . 4.8 . 5.4 6.0
Retention Time, nrin.
CDNB
(b)
0.6 1.2 1.8 2.4 3.0 3.6 4.2 . 4.8
Retention Time, min.
5.4 6.0
FIGURE 42. GC-ECD CHROMATOGRAM OF (a) POTW EFFLUENT, AND (b)
POTW EFFLUENT SPIKED WITH CDNB AT THE 1.0 ug/L LEVEL,
AFTER FLORISIL CLEANUP.
98
-------
10 11 12
Retention Time, min.
(a)
r
16 17
—T—
8
Unidentified Peaks
Dinocap
10
*—r-
11
' i
12
(b)
/•Dinocap peak used
for quantification
13
14
15
16 17
Retention Time, min.
FIGURE 43. GC-ECD CHROMATOGRAM OF (a) POTW EFFLUENT, AND (b) POTW
. EFFLUENT SPIKED WITH DINOCAP Af THE 1.0 pg/L LEVEL,
AFTER FLORISIL CLEANUP.
99
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TABLE 21. RECOVERIES OF DINITRO AROMATIC PESTICIDES FROM WATER
(c)
Compound
Basalin
Basalin
Basalin
Basalin
CDNB
CDNB
CDNB
CDNB
Dinocap
Dinocap
Dinocap
Dinocap
Spike
Level,
wg/L
0.1
1.0
0.1
1.0
0.1
1.0
0.1
1.0
0.1
1.0
0.1
1.0
Before Cleanup
Matrix(a)
1
1
2
2
1
1
2
2
1
1
2
2
Blank
Level
ND(b)
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Recovery,
%
130
113
94
113
91
69
78
71
78
77
76
72
Standard
Deviation, X
12
4
6
2
8
5
2
2
7
4
40
3
Blank
Level
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
After Cleanup
Recovery,
126
109
74
108
89
71
76
70
26
72
123
80
Standard
Deviation,:
8
10
3
3
6
5
4
2
3
14
53
10
(a) l=Reagent water; 2=Columbus POTW secondary effluent.
(b) ND=not detected.
(c) Recovery data are averages of three replicate analyses.
-------
the method stated that CDNB should elute in Florisil Fl (methylene chloride),
CDNB eluted in Florisil F2 (10 percent acetone in methylene chloride).
Chromatograms obtained from the GC analyses of POTW effluent extracts, unspiked
and spiked with CDNB at the 1.0 vg/L concentration level, are shown in Figure 39.
The same extracts, after Florisil cleanup, are shown in Figure 42. CDNB
recovery data are given in Table 21.
Dinocap recovery studies were conducted at the 0.1 and 1.0 vg/L concen-
tration levels. Data obtained from the 0.1 vg/L concentration levels were
generally not repeatable and unreliable. This concentration level was very
close to the EDL for dinocap, making identification and integration of dinocap
peaks difficult. Recoveries of dinocap from samples spiked at the 1.0 yg/L
concentration level were generally low, ranging from 72 to 77 percent.
Recoveries of dinocap at this concentration level were not significantly
changed when the Florisil cleanup step was used. Chromatograms obtained from
the GC analyses of POTW effluent extracts, unspiked and spiked with dinocap
at the 1.0 vg/L concentration level, are shown in Figure 40. The same
extracts, after Florisil cleanup, are shown in Figure 43. Dinocap recovery
data are given in Table 21.
The EDLs for basal in and CDNB were determined by analyzing 0.0005 ug/mL
standard solutions of basalin and CDNB in hexane; the resultant Chromatograms
are shown in Figures 44 and 45. This basalin solution yielded a S/N of 4.8.
The EDL, defined as the concentration in water yielding a S/N equal to 5.0,
was calculated to be 0.0005 vg/L of basalin. The CDNB solution yielded a
S/N of 5.3. The EDL was calculated to be 0.0005 vg/L of CDNB. The EDL for
dinocap was determined by analyzing a 0.05 ug/mL solution of dinocap in
hexane; the resultant chromatogram is shown in Figure 46. This dinocap
solution yielded a S/N of 1.9. The EDL was calculated to be 0.1 vg/L of
dinocap. The EDL does not take into account any interferences or recovery
losses that might be encountered from a particular matrix.
The average peak area of the 0.1 pg/mL standard solution of dinocap
obtained from a chemical supply house was 22 percent lower than the average
peak area of the same standard prepared from dinocap obtained from the reference
standards repository. It can only be assumed that the dinocap obtained from
the chemical supply house was not as pure as the supplier indicated.
RECOMMENDATIONS
GC analysis conditions specified in the dinitro aromatic pesticides
analysis method yielded excessively long elution times for all of the dinitro
aromatic pesticides. The method should be modified by raising specified
column temperatures as described earlier.
The analytical conditions and cleanup procedure specified in this method
to determine the dinitro aromatic pesticides in water seem acceptable. However,
recoveries of two of the compounds, CDNB and dinocap, are slightly low. This
indicates that further study of compound long term stability in water and the
efficiency of the extraction procedure may be warranted. Studies should be
101
-------
o
ro
5 = 0.0005 yg/L
EDL = 0.0005 /L x
4.2 4.3 4.4
4.5
4.6 4.7 4.8 4.9 5.0 5.1
Retention Time, min.
FIGURE 44. 6C-ECD CHROMATOGRAM OF BASAL IN STANDARD EQUIVALENT TO 0.0005 yg/L IN WATER
USED TO DETERMINE METHOD EDL.
-------
EDL = 0.0005 uq/L x x 5 -0.0005 wg/L
o
CO
2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
Retention Time, min.
FIGURE 45. 6C-ECD CHROMATOGRAM OF CDNB STANDARD EQUIVALENT TO 0.0005 wg/L IN WATER
USED TO DETERMINE METHOD EDL.
-------
EDL = 0.05 yg/L x 0.022 x 5 = '0.1 p
-------
performed to determine the stability of CDNB and dinocap in water. It is
possible that equilibrium between the two phases during extraction is not
being achieved. Use of continuous extraction or perhaps tumbling might
improve recovery efficiencies of the compounds. Tumbling is preferable to
use of separatory funnels in this case since maximum mixing of the two phases
is assured. Mixing achieved using separatory funnels is operator dependent.
105
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SECTION 10
ANALYSIS OF ORGANOCHLORINE PESTICIDES
IN WASTEWATER BY GAS CHROMATOGRAPHV
INTRODUCTION
Chlorothalonil (XXIV) is effective against a broad range of plant
pathogens. The IUPAC name for Chlorothalonil is tetrachloroisophthalonitrile
and its CAS registry number is 1879-45-6. Common synonyms for chlorothalonil
include Bravo, Oaconil 2787, and Exotherm Termil. Chlorothalonil forms color-
less crystals with a melting point of 250-251°C. Chlorothalonil has a
solubility in water of 0.6 mg/kg at 25°C and is soluble in most organic
solvents. Chlorothalonil is stable to acid, base and light. The acute
oral LD50 for rats for chlorothalonil is >10,000 mg/kg (86).
DCPA (XXV) is a preemergent herbicide. The IUPAC name for DCPA is
dimethyl tetrachloroterepthalate and its CAS registry number is 1861-32-1.
Common synonyms for DCPA include chlorthal-dimethyl and Dacthal. DCPA forms
colorless crystals with a melting point of 156°C. DCPA has a solubility in
water of <0.5 mg/L at 25CC and is soluble in most organic solvents. The
acute oral LD50 for DCPA is >3000 mg/kg (87).
106
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Dichloran (XXVI) is a fungicide. The IUPAC name for dichloram is
2,6-dichloro-4-nitroaniline and its CAS registry number is 99-30-9. Common
synonyms for dichloran include Allisan, Botran, CDNA, AL-50, CNA, DCNA,
dichloran, and Resistan. Dichloran forms yellow crystals with a melting
point of 192-194°C. Dichloran is insoluble in water and moderately soluble
in most organic solvents. The acute oral LD50 for dichloran for rats is
1500-4000 mg/kg.
Methoxychlor (XXVII) is a nonsystemic contact and stomach insecticide.
The IUPAC name for methoxychlor is 1,1,l-trichloro-2,2-bis(4-methoxyphenyl)-
ethane and its CAS registry number is 72-43-5. A common synonym for methoxychlor
is Marlate. Methoxychlor is a grey flaky powder which is practically insoluble
in water and is soluble in most organic solents. Methoxychlor is resistant
to oxidation and heat. The acute oral LD50 for rats for methoxychlor is
6000 mg/kg (88).
OCH,
XXVII
Permethrin (XXVIII) is a contact insecticide. The IUPAC name for
permethri n i s 3-phenoxybenzyl ( 1 RS) -ci s , trans-3- (2 ,2-di chl orovinyl } -2 ,2-
dimethyl cyclopropanecarboxylate and its CAS registry number is 52645-53-1.
Technical permethrin is a yellowish-brown liquid which partially crystallizes
OFh
XXVIII
107
-------
at ambient temperatures and Is completely liquid at temperatures greater than
60°C. Permethrin has a solubility in water of 0.1 mg/L at 20'C and is soluble
in most organic solvents. Permethrin degrades in light and is more stable in
acid than in base. The oral LD50 for permethrin in rats is 430-4000 mg/kg,
the exact number depending upon the cis/trans ratio of the permethrin (89).
Analysis methods for the organochlorine pesticides in various matrices
have been reported. These methods used GC coupled with EC and Hall detectors
(24,35,51,52,53,58,90,91,92,93,94,95). An HPLC method for the determination
of chlorothalonil and permethrin is also reported (33).
The method provided by the Project Officer for evaluation for determination
of organochlorine pesticides consisted of adjustment of the sample pH to the
range of 5 to 9 by addition of dilute sodium hydroxide or sulfuric acid;
extraction of the sample with methylene chloride using a separatory funnel;
drying of the sample using anhydrous sodium sulfate; concentration of the
sample to 10 ml after exchanging the solvent with hexane; and analysis of the
sample extract by packed column GC-ECD. A cleanup procedure using Florisil
for samples containing DCPA and dichloran is included in the method. A
cleanup procedure using 3 percent deactivated silica gel for samples containing
chlorothalonil, methoxychlor, and permethrin was included in the method.
CONCLUSIONS
A method designed to determine organochlorine pesticides in wastewaters
was evaluated. The extraction, cleanup, and analysis portions of the method
were found to be acceptable for determination of cis- and trans-permethrin
in reagent water and POTW effluent. Recoveries of chlorothalonil and dicloran
from water could not be determined because of the presence of interferences.
The method may not be applicable to samples containing chlorothalonil and
dicloran at concentration levels less than 1 to 10 pg/L because of the likeli-
hood of the presence of interferences. Recoveries of DCPA and methoxychlor
were concentration and/or matrix dependent. The method was acceptable at the
higher spiking level of 0.2 pg/L for DCPA and 10 ug/L for methoxychlor with
recoveries being generally greater than 75 percent.
EXPERIMENTAL
The following procedure was outlined in the organochlorine pesticide
analysis method:
1. Place sample (approximately 1 liter) into a 2-liter
separatory funnel, and adjust the pH of the sample to
within the range of 5 to 9 with dilute sodium hydroxide
or sulfuric acid.
2. Extract the sample with three 60-mL portions of methylene
chloride and combine the extracts.
108
-------
3. The combined extracts are dried by pouring through a
chroma tography column containing 10 cm of anhydrous
sodium sulfate.
4. ,ncentrate the combined extracts to an apparent volume
of 1 ml using K-D equipment with the water bath at 80 to 85°C.
The extracts are reconcentrated to 10 mL after the addition
of 50 ml of hexane using K-D equipment with the water bath
at 90 to 95°C.
5. A Florisil cleanup procedure is used for samples that contain
DCPA and dichloran.and that require cleanup. A specified amount
of Florisil, determined by its lauric acid value, is placed in
a chromatography column. The sample is applied to the column
in hexane, and the co7uran is eluted with 200 mi of 6 percent
ethyl ether in hexane, which is discarded. The column is then
eluted with 200 mL of 15 percent ethyl ether in hexane. This
fraction contains OCPA and dichloran. A cleanup procedure using
3 percent deactivated silica gel is used for samples that contain
chlorothalonil, methoxychlor, and the permethrins, and that
require cleanup. Silica gel, 3.5 grams, is placed in a
chromatography column. The sample is applied to the column in
hexane, and the column is eluted with 25 ml of hexane and 25 ml
of 6 percent methylene chloride in hexane, both of which are
discarded. The column is then eluted with 25 ml of 25 percent
methylene chloride in hexane. This fraction contains chlorothalonil,
methoxychlor, and the permethrins. The fractions obtained from
the Florisil and silica gel cleanup procedures are concentrated
to 10 mL after the addition of 50 mL of hexane using K-D equipment
with the water bath at 90 to 95°C.
6. Analyze the sample by 6C-ECD using the following conditions:
- 180 cm long by 2 mm ID glass column packed with
1.5 percent OV-17/1.95 percent OV-210 on
Chromosorb w-HP (100/120 mesh);
- 5 percent methane/95 percent argon carrier gas
at 30 mL/min flow rate;
- oven temperature of 200°C isothermal for chlorothalonil,
DCPA, dicloran, and methoxychlor, and 220°C isothermal
for the permethrins;
- injection volume of 5 nL.
The EDLs for the dinitro aromatic pesticides originally listed in the
method were 0.002 pg/L for chlorothalonil, DCPA, and trans-permethrin, and
0.001 vg/L for dicloran, methoxychlor, and cis-permethrin. The EDLs for
methoxyclor and the permethrins were estimated to be too low; EDLs of
0.1 ug/L were considered to be more likely. After telephone consultation
with the EPA Task Officer, it wcs agreed that method evaluations would be
done using spike levels of 1.0 and 10 yg/L for methoxychlor, cis-permethrin,
and trans-permethrin.
109
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Samples processed Included the following:
1. Triplicate reagent water samples. Reagent water
was obtained from a Millipore system.
2. Triplicate reagent water samples spiked with
chlorothalonil and DCPA at the 0.02 pg/L concentration
level, dicloran at the 0.01 pg/L concentration level,
and methoxychlor, cis-permethrin, and trans-permethrin
at the 1 pg/L concentration level.
3. Triplicate reagent water samples spiked with
chlorothalonil and DCPA at the 0.2 pg/L concentration
level, dicloran at the 0.1 pg/L concentration level,
and methoxychlor, cis-permethrin, and trans-permethrin
at the 10 vg/L concentration level.
4. Triplicate POTW secondary effluent samples. POTW
secondary effluent was obtained from the City of Columbus.
5. Triplicate POTW secondary effluent samples spiked with
chlorothalonil and DCPA at the 0.02 pg/L concentration
level, dicloran at the 0.01 pg/L concentration level,
and methoxychlor, cis-permethrin, and trans-permethrin
at the 1 pg/L concentration level.
6. Triplicate POTU secondary effluent samples spiked with
chlorothalonil and DCPA at the 0.2 pg/L concentration
level, dicloran at the 0.1 pg/L concentration level,
and methoxychlor, cis-permethrin, and trans-permethrin
at the 10 pg/L concentration level.
A second set of samples as described in points 1-6 were prepared and
divided in half; each half was treated with either silica gel or Florisil
cleanup procedures and reanalyzed by GC-ECD. Attempts were made to obtain
recovery data for all compounds both after silica gel and Florisil cleanup
procedures. All fractions were analyzed for all of the dinitro aromatic
compounds.
Recoveries were determined by comparison to standard solutions of
chlorothalonil and DCPA prepared at the 1.0, 5.0, and 20 pg/L concentration
levels, dicloran prepared at the 0.5, 2.5, and 10 pg/L concentration levels,
and methoxychlor, cis-permethrin, and trans-permethrin prepared at the 50,
200, and 1500 pg/L concentration levels in hexane. These concentration
levels were equivalent to 0.01, 0,05, and 0.2 pg/L of chlorothalonil and
DCPA, 0.005, 0.025, and 0.1 pg/L of dicloran, and 0.5, 2.0, and 15 pg/L of
methoxychlor, cis-permethrin, and trans-permethrin in the original samples
assuming a final extract volume of 10 mL. Response factors were calculated
for the standards and used to determine concentration levels in the above-
mentioned reagent water and POTW effluent samples.
110
-------
The method EDLs, defined as the concentration of each organochlorine
pesticide in a sample yielding a S/N of 5, were determined by injecting
0.25 pg/L standard solutions of chlorthalonil, dichloran, and DCPA, 10 pg/L
standard solution of cis-permethrin and trans-permethrin, and a 5.0 pg/L
solution of methoxychlor prepared in hexane. The solutions were equivalent
to 0.0025 pg/L concentrations of chlorothalonil, dichloran, and DCPA, 0.1 pg/L
concentrations of cis-permethrin and trans-permethrin, and 0.05 pg/L concen-
tration of methoxychlor in a water sample.
QUALITY ASSURANCE
Instrumentation was set up as described in the method. Sensitivity
achieved was approximately that reported in the method for chlorothalonil,
DCPA, and dicloran. As expected, sensitivity achieved was approximately one
order of magnitude lower for methoxychlor and two orders of magnitude lower
for cis-permethrin and trans-permethrin. Calibration standards consisted of
solutions of chlorothalonil and DCPA prepared at the 1.0, 5.0, and 20 yg/L
concentration levels, dicloran prepared at the 0.5. 2.5, and 10 pg/L concen-
tration levels, and methoxychlor, cis-permethrin, and trans-permethrin
prepared at the 50, 200, and 1500 pg/L concentration levels in hexane. Each
calibration standard was analyzed in duplicate prior to analysis of any
evaluation samples. A selected calibration standard was then analyzed after
every five evaluation samples. Response factors were calculated for each
calibration run by dividing the equivalent pesticide concentration level in
the sample in pg/L by the pesticide peak area. Resultant calibration data
are reported in Table 22. Response factors were repeatable over the entire
calibration range for all of the organochlorine pesticides. Response factors
used for quantification of chlorothalonil, DCPA, dichloran, methoxychlor,
cis-permethrin, and trans-permethrin were 0.0058, 0.0053, 0.0056, 0.018, 0.11,
and 0.089, respectively.
Standards of all six organochlorine pesticides were obtained from two
Independent sources. Calibration standards used for quantification of these
compounds in the water samples were prepared from compounds obtained from the
reference standards repository of EPA-HERL. Standard solutions of the six
organochlorine pesticides were also prepared from compounds obtained from a
chemical supply house; these solutions were analyzed in duplicate and compared
to equivalent standard solutions prepared from the compounds obtained from
the reference standards repository.
RESULTS AND DISCUSSION
Several unidentified peaks appeared in both spiked and unspiked reagent
water and POTW extracts. Some of these peaks coeluted with chlorothalonil
and dicloran and precluded recovery determinations for these two pesticides.
In most cases, the Florisil or silica gel cleanup procedures removed some of
the interfering peaks. However, enough of the peaks remained to make
recovery determinations for chlorothalonil and dicloran impossible. It is
unlikely that these peaks were actually chlorothalonil and dicloran since
they were partially removed by the cleanup procedures. The source of these
interferences was not identified. Significant problems due to interferences
111
-------
TABLE 22. ORGANOCHLORINE PESTICIDES CALIBRATION DATA
Compound
Chlorothalonil
Chlorothalonil
Chlorothalonil
DCPA
DCPA
DCPA
Dicloran
Dicloran
Dicloran
Methoxychlor
Methoxychlor
Methoxychlor
Cis-permethrin
Cis-permethrin
Cis-permethrin
Trans-permethrin
Trans-permethrin
Trans-pertnethrin
Concen-
tration.
pg/Lfa)
0.01
0.05
0.20
0.01
0.05
0.2
0.005
0.025
0.1
0.5
2.0
15
0.5
2.0
15
0.5
2.0
15
Average
Peak
Area
1.73
8.46
35.6
1.68
10.3
40.0
0.80
4.55
19.4
25.4
117
858
3.9
18.5
142
5.54
22.5
170
Standard
Deviation,
%
21
19
14
14
4
4
12
7
4
16
15
6
20
13
10
19
7
4
Number of
Replicates
8
7
8
8
8
8
8
8
8
8
7
8
6
8
8
5
4
4
Average
Response
Factors
0.0058
0.0059
0.0056
0.0060
0.0048
0.0050
0.0063
0.0055
0.0052
0.020
0.017
0.017
0.13
0.11
0.11
0.090
0.089
0.088
(a) Equivalent concentration of compound in water sample.
were not observed for the other four compounds. Chromatograms obtained from
the analyses of unspiked reagent water and POTW water samples, both before
and after cleanup, are shown in Figures 47-51. Chromatograms obtained from
the analyses of POTW effluent samples, unspiked and spiked with Chlorothalonil
at the 0.2 pg/L and dicloran at the 0.1 pg/L concentration levels are shown
in Figure 47. The Florisil cleanup procedure was used for samples containing
dicloran and the silica gel cleanup procedure was used for samples containing
chlorathalonil. Chromatograms obtained from the same sampler after silica
gel or Florisil cleanup are shown in Figures 49 and 50. Data indicating the
levels of interfering peaks found in the sample extracts are given in
Table 23.
Recoveries of 0.02 pg/L levels of DCPA from reagent water were 128 + 10
percent before Florisil cleanup and 7" ± 25 percent after cleanup. Recoveries
of 0.2 pg/L levels of DCPA from reage, t water before ana after Florisil cleanup
were more repeatable, 94 ± 11 percent and 84 ± 11 percent, respectively These
data may indicate that the reliability of the method is concentration dependent
112
-------
(a)
2.0 4.0 6.0 8.0 10.0 12.0
Retention Time, min.
14.0 16.0 18.0 20.0
2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Retention Time, min.
FIGURE 47. 6C-ECD CHROMATOGRAM OF (a) POTW EFFLUENT AND
(b) POTW EFFLUENT SPIKED WITH 0.2 yg/L CHLOROTHALONIL,
0.2yg/LDCPA, 0.1 yg/L DICLORAN, AND 10 yq/L
METHOXYCHLOR.
113
-------
(a)
2.0 4.0 6.0 8.0 10.0 12.0 14.0
Retention Time, min.
18.0 20.0
Cis-Permettirin
(b)
Trans-Permethrin
2.0 4.0 6.0 8.0 10.0 12.0
Retention Time, m1n.
14.0 16.0 18.0 10.0
FIGURE 48. GC-ECD CHROMATOGRAM OF (a) POTW EFFLUENT, AND (b)
POTW EFFLUENT SPIKED WITH CIS-PERMETHRIN AND TRANS-
PERMETHRIN AT THE 10 ug/L LEVELS.
114
-------
(a)
2.0
4.0 6.0 8.0 10.0 12.0
Retention Time, min.
14.0 16.0 . 16.0 20.0
(b)
6.0 8.0 10.0 12.0
Retention Time, min.
18.0 20.0
FIGURE 49. GC-ECD CHROMATOGRAM OF (a) POTW EFFLUENT, AND (b)
POTW EFFLUENT SPIKED WITH 0.1 pg/L DICHLORAN AND
0.0? ug/L DCPA AFTER FLORISIL CLEANUP.
115
-------
(a)
AJL -
0.2
0.4
6.0 8.0 10.0 12.0
Retention Time, nrin.
14.0 16.0 18.0 20.0
(b)
6.0 8.0 10.0 12.0 14.0
Retention Time, min.
16.0 . 18.0 20.0
FIGURE 50. GC-ECD CHROMATOGRAM OF (a) POTW EFFLUENT, AND (b) POTW
EFFLUENT SPIKED WITH 0.2 ug/mL CHLOROTHALONIL AND
10 ug/L METHOXYCHLOR AFTER SILICA GEL CLEANUP.
116
-------
(a)
2.0 4.0 6.0 8.0 10.0 12.0
Retention Time, min.
14.0 16.0 18.0 20.0
(b)
Trans-permethrin
Z.O
4.0 6.0 8.0 10.0 12.0 14.0 16.0 . 18.0 20.0
Retention Time, min.
FIGURE 51. GC-ECD CHROMATOGRAM OF (a) POTW EFFLUENT, AND (b) POTW
EFFLUENT SPIKED WITH CIS-PERMETHRIN AND TRANS-PERMETHRIN
AT THE 10 yg/L LEVELS, AFTER SILICA GEL CLEANUP.
117
-------
TABLE 23. RECOVERIES OF ORGANOCHLORINE PESTICIDES FROM WATER
(0
co
Spike
Level
Compound ug/L
Chlorothalonil 0.02
Chlorothalonil 0.2
Chlorothalonil O.C2
Chlorothalonil 0.2
DCPA 0 0?
DCPA 0.2
DCPA 0.02
DCPA 0.2
Dicloran 0.01
Dicloran 0.1
Dicloran 0.01
Dicloran 0.1
Methoxychlor 1.0
Methoxychlor 10
Methoxychlor 1.0
Methoxychlor 10
Cis-permethrin 1.0
Cis-permethrin 10
Cis-permethrin 1.0
Cis-permethrin 10
Trans-permethrin 1-0
Trans-permethrin 10
Trans-permethrin 1.0
Trans-permethrin 10
(a) l=Reagent water; 2
(b) ND = not detected.
(c) Recovery data are
(d) Recovery data not
Before Cleanu
, i Blank
Recovery,
Matrix13' Level %
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1.2
1.2
7.3
7.3
ND^k)
ND
ND
ND
3.6
3.6
29
29
ND
ND
ND
NO
ND
ND
ND
ND
ND
ND
ND
ND
=Columbus POTW secondary
averages of
calculated;
(d)
(d)
(d)
(d)
128
94
ND
71
(d)
(d)
(d)
(d)
57
106
47
99
94
91
89
85
in
98
85
90
effluent.
P
After Cleanup
Standard Blank Recovery, Standard
Dev., % Level
_..
--
--
--
18
IT
-.
5
__
--
—
--
1
12
12
2
9
2
8
3
4
3
2
2
0.21
0.21
0.52
0.52
ND
ND
0.011
0.011
3.8
3.8
4.6
4.6
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
*
(d)
(d)
(d)
(d) (e)
73 (51)
84 (27)'
62 (46)
76 (40)
(d)
(d)
(d)
(d)
37
86
40
90
91
128
97
98
83
108
41
95
Dev.,%
__
--
--
--
25 (42)
11 (22)
5 (57)
2 (4)
--
--
—
—
8
12
27
14
6
17
14
27
12
13
11
29
three replicate analyses.
compound was
(e) A Florisil cleanup procedure was specified
for DCPA after sil
not detected
for DCPA in
because of
method; data
interfering peaks.
obtained
ica gel cleanup are given in parentheses.
-------
Recoveries of 0.02 yg/L levels of DCPA from POTW effluent before and after
Florisil cleanup were 0 percent and 62 ± 4.7 percent, respectively. An
interfering peak was introduced at the 0.01 yg/L level to these sample
extracts during the Florisil cleanup procedure. This level is comparable
to the amount of DCPA spiked into the POTW effluent. It is possible that
0.2 yg/L levels of DCPA are not recovered from the POTW effluents, and that
the 62 percent recovery figure is due to some variability in the interfering
compound peak area. Recoveries of 0.2 yg/L levels of DCPA from POTW
effluent before and after Florisil cleanup were again more repeatable than
those from the lower spiking level, 71 ±5.0 percent and 76 ± 2.4 percent,
respectively. These recoveries, however, are significantly lower than those
from reagent water spiked at the 0.2 yg/L level with DCPA. DCPA recoveries
seem to be not only concentration dependent but also matrix dependent.
Recoveries of DCPA after silica gel cleanup were generally lower than those
obtained from equivalent samples after Florisil cleanup. Chromatograms
obtained from the analyses of unspiked POTW effluent and POTW effluent spiked
with DCPA at the 0.2 yg/L level, prior to Florisil cleanup, are shown in
Figure 47. Chromatograms obtained from the same samples after Florisil
cleanup are shown in Figure 49. DCPA recovery data are given in Table 23.
Recoveries of methoxychlor spiked into reagent water or POTW effluent
at the 1.0 yg/L levels were generally low, ranging from 37 to 57 percent.
Recoveries increased to 86 to 106 percent when the methoxychlor spiking level
was raised to 10 yg/L. The data indicate that recoveries of methoxychlor
from water are concentration dependent. The silica gel cleanup procedure did
not significantly affect methoxychlor recoveries. Methoxychlor was not detected
in samples after Florisil cleanup. Chromatograms obtained from the analyses of
unspiked POTW effluent and POTW effluent spiked with methoxychlor at the 10 yg/L
level, prior to silica gel cleanup, are shown in Figure 47. Chromatograms
obtained from the same samples after silica gel cleanup are shown in Figure 50.
Methoxychlor recovery data are given in Table 23.
Recoveries of cis-permethrin and trans-permethrin were generally greater
than 83 percent, regardless of the compound concentration level or sample
matrix. The exception was the low recovery of 1.0 yg/L levels of trans-
permethrin from reagent water. Only 41 percent of the trans-permethrin was
recovered from these samoles. The reason for this low recovery is not known.
The data indicate that the silica gel cleanup procedure does not lead to
significant losses of cis- or trans-permethrin. Records do not indicate a
problem in sample preparation. Cis- and trans-permethrin were not detected
in samples after Florisil cleanup. Chromatograms obtained from unspiked POTW
effluent and POTW effluent spiked at the 10 yg/L level with cis- and trans-
permethrin, before silica gel cleanup, are shown in Figure 48. Chromatograms
obtained from the same samples after silica gel cleanup are shown in Figure
51. Recovery data for cis- and trans-permethrin are given in Table 23.
The EDLs for chlorothalonil, DCPA, and dicloran were determined by
analyzing 0.25 yg/L standard solutions of these compounds in hexane; the
resultant Chromatograms are shown in Figures 52-54. The chlorothalonil
solution yielded a S/N of 8.7. The EDL, defined as the concentration in
water yielding a S/N equal to 5.0, was calculated to be 0.001 yg/L of
chlorothalonil. The DCPA solution yielded a S/N of 4.5. The EDL was cal-
culated to be 0.003 yg/L of DCPA. The dicloran solution yielded a S/N of
119
-------
EDL = 0.025 ug/L x
0.008
O5F
-
-I- r -r -t—» 1- f i- f -r-t- r I--T-I-T- j •« I-»
1.4 1.8 2.2 2.6
X 5 = 0.001 yq/L
,-.,..,- f -f , 7-t—1
4.2 4.8 5.0
Retention Time, min.
FIGURE 52. GC-ECD CHROMATOGRAM OF CHLOROTHALONIL STANDARD EQUIVALENT TO
0.0025 pg/L IN WATER USED TO DETERMINE METHOD EDL.
-------
EDL = 0.0025 gq/L x 2^J| x 5 * Q.003 yq/L
-,-,., -,. j .., ,. .j.-r j _, _^_r . , ^.T.r.r r.j ,., ,.., j.f , .r..r^..r n., t _j. , ,r r-T j- r ^
2.3 2.6 2.9 3.2 3.5 3.8 4.1 4.4 4.7 5.0
Retention Time, min.
FIGURE 53. GC-ECD CHROMATOGRAM OF DCPA STANDARD EQUIVALENT TO 0.0025 yg/l IN
WATER USED TO DETERMINE METHOD EDL.
-------
ro
ro
EDL = 0.0025 wg/L x Ml, x 5 = 0.002 ug/L
••ft t-t-T-| 1 f t -r -f -ft— i- »'T r-f-i t | — r t-t «
-t-i t r t--r-| -r-t-t- t'-j--
1.4 1.8 2.2 2.8 3.0 3.4 3.8 4.2 4.8 5.0
Retention Time, min.
FIGURE 54. 6C-ECD CHROMATOGRAM OF DICLORAN STANDARD EQUIVALENT TO 0.0025 yg/L
IN WATER USED TO DETERMINE METHOD EDL.
-------
7.6. The EDL was calculated to be 0.002 wg/L of dicloran. The EDL for
methoxychlor was determined by analyzing a 5 wg/mL solution of methoxychlor
In hexane; the resultant chromatogram 1s shown In Figure 55. The methoxy-
chlor solution yielded a S/N of 6.9. The EOL was calculated to be 0.04 ug/L
of methoxychlor. The EDLs for cls-permethrin and trans-permethrln were
determined by analyzing 10 ug/L standard solutions of these compounds in
hexane; the resultant chromatoqrams are shown in Figures 56-57. The cis-
permethrin solution yielded a S/N of 3.2. The EDL was calculated to be
0.2 vg/L of cis-permethrin. The trans-permethrin solution yielded a S/N
of 2.2. The EDL was calculated to be 0.2 yg/L of trans-permethrin. The
EDL does not take into account any interferences or recovery losses that
might be encountered from a particular matrix.
Average peak areas from the analyses of standards of the organochlorine
pesticides obtained from the chemical supply house did not vary by more
than +10 percent with the exception of cis-permethrin. The peak areas
obtained from the chemical supply house souce of cis-permethrin were 40
percent lower than those obtained from the reference standards repository.
It can only be assumed that the standard obtained from the chemical supply
house was not as pure as was specified bj the supplier.
RECOMMENDATIONS
The method is acceptable for the determination of cis-permethrin and
trans-permethrin in water. The method was not found to be suitable for
determination of chlorothalonil and dicloran in water samples. It was not
possible to determine recoveries of chlorothalonil and dicloran from water
due to the presence of interfering peaks. It is not unusual to have problems
with interferences when an electron capture detector is used. This problem
is magnified when the compounds of interest elute early, since chlorine-
containing low molecular weight compounds are often present in water samples
or introduced during processing of samples in the laboratory. It may be
necessary to modify GC parameters or to use another GC column to change the
chromatography of these two compounds. It may also be necessary to use
another detector that is chlorine or nitrogen specific, such as a Hall
detector in the halogen mode or a nitrogen-phosphorus detector to reduce
the interference problem. Recoveries of DCPA and methoxychlor were concen-
tration and/or matrix dependent. Other extraction methods such as continuous
extraction or tumbling should be investigated to ascertain if the recoveries
of DCPA or methoxychlor from water can be improved. The amount of mixing
achieved between aqueous and organic phases using separatory funnels is
operator dependent. Use of continuous extractors or tumbling assures
optimum equilibrium conditions.
123
-------
11.0 12.0 13.0 14.0 15.0 16.0 17.0 18.0 19.0 20.0
Retention Time, mln.
FIGURE 55. GC-ECD CHROMATOGRAM OF METHOXYCHLOR STANDARD EQUIVALENT TO 0.05 uq/L
IN WATER USED TO DETERMINE METHOD EDL.
-------
EDL - 0.1 yg/L x x 5 = 0.15 uq/L
0.033 MV
-r-f-|- t—t -t- I • f—t •• «"i'i' -1—r-t-f-j t f-» • | i i i . j i i i fft > i-f-f» i-r-i'i i-i-i-t—j
8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0
Retention Time, min.
FIGURE 56. GC-ECD CHROMATOGRAM OF CIS-PERMETHRIN STANDARD EQUIVALENT TO 0.1
IN WATER USED TO DETERMINE METHOD EDL.
-------
ro
CM
EDL = 0.1 yg/L x JjJJJ x 5 = 0.22 yg/L
0.030 MV
r -ft • t — | r
8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0
Retention Time, m1n.
FIGURE 57. 6C-ECD CHROMATOGRAM OF TRANS -PERMETHRIN STANDARD EQUIVALENT TO
0.1 yg/L IN WATER USED TO DETERMINE METHOD EDL.
-------
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