USGS-NWQL: O-3402-03: Organophosphate pesticides, Whole water, Gas Chromatography

Summary
Analytes
Revision
Data and Sites

Official Method Name

Organophosphate pesticides, Whole water, Gas Chromatography

Current Revision

2003

Media

WATER

Instrumentation

Gas Chromatograph (Unspecified Detector)

Method Subcategory

Organic

Method Source

USGS-NWQL

Citation

Jha, V.K., and Wydoski, D.S., 2003, Methods of Analysis of the U.S. Geological Survey National Water Quality Laboratory ? Determination of Organophosphate Pesticides in Whole Water by Continuous Liquid-Liquid Extraction and Capillary-Column Gas Chromatography with Flame Photometric Detection, U.S. Geological Survey Water-Resources Investigations Report 03-4139, 34 p.

Brief Method Summary

Reagent grade NaCl (60 g) is added to all field samples for preservation, including laboratory blank and spike samples. Organophosphates and degradates are extracted from whole-water samples using continuous liquid-liquid extraction, and methylene chloride is used as an extraction solvent. The extract is concentrated down to 4 to 6 mL on a heating mantle. The concentrate is further evaporated by using nitrogen to a volume of 1 mL. Finally, the extracts are solvent exchanged to ethyl acetate and analyzed by capillary-column GC/FPD with the external standard quantitation method.

Scope and Application

This method is suitable for the determination of 20 parent organophosphate pesticides (OPs) and 5 related OP degradation products in whole-water samples. Three of the compounds -- disulfoton, ethion monoxon, and O-ethyl-O-methyl-S-propylphosphorothioate -- are reported permanently with an estimated concentration because of variable instrumental and extraction stability problems.
This method is applicable to the determination of pesticides and pesticide degradates that are (1) efficiently isolated from the sample matrix with methylene chloride extraction using a continuous liquid-liquid extractor, (2) chromatographically resolved and identified using a gas chromatograph (GC) equipped with flame photometric detectors (FPD), and (3) sufficiently stable to chemical or thermal degradation to allow accurate quantification by using all sampling and analysis steps of the method.

Applicable Concentration Range

0.005-0.100

Interferences

There are many organophosphate compounds in natural matrices that GC/FPD will detect. This method is designed to minimize false positives through dual GC column confirmation. Mass-spectral confirmation also should be used to confirm identification, if uncertain. Sulfur and organosulfur compounds and unknown organophosphate compounds occasionally might interfere with qualification and quantification of other individual organophosphate compounds.

Quality Control Requirements

Minimum QC requirements include the following: (1) analysis of laboratory reagent blank (LRB); (2) determination of surrogate standard compound recoveries in each sample, LRB, and laboratory reagent spike (LRS); (3) determination of compound recoveries in the LRS; and (4) assessment of the GC/FPD chromatographic performance.

Sample Handling

Samples are collected in pre-cleaned and baked 1-L, 33-mm neck, amber glass bottles with Teflon-lined screw caps and shipped chilled by overnight mail to the laboratory. After the samples are logged into the laboratory information management system, 60 g of NaCl is added to the samples for preservation and they are stored at 4^oC until ready for extraction (usually within 7 days).

Maximum Holding Time

7 days

Relative Cost

Sample Preparation Methods

This method has 26 analytes associated with it.

Analyte	Detection Level	Bias	Precision	Spiking Level
Carbophenothion(786-19-6) Acarithion Carbofenotion Carbophenothion Carbophenothion (ANSI) Danifos ENT 23, 708 Garrathion Oleoakarithion Phosphorodithioic acid, S-[[(p-chlorophenyl)thio]methyl] O,O-diethyl ester (6CI, 8CI) R 1303 R 1303 (pesticide) S-[[(p-Chlorophenyl)thio]methyl] O,O-diethyl phosphorodithioate Stauffer R 1303 Trithion	0.004 ug/L	80% Rec (SL)	9.98 % RSD (SL)	2.00 ug/L
Chlorpyrifos(2921-88-2) Chloropyriphos Chlorpyrifos Chlorpyrifos (ANSI) Chlorpyrifos(dursban) Dursban Lorsban	0.003 ug/L	77% Rec (SL)	8.95 % RSD (SL)	0.02 ug/L
Diazinon(333-41-5) Alfa-tox Basudin Diazide, Diazinone, Diazitol, Diazol Diazinon Diazinon (ANSI) Diazitol Dimpylate Dipofene Spectracide	0.008 ug/L	81% Rec (SL)	18.46 % RSD (SL)	2.00 ug/L
Dimethoate(60-51-5) Cygon Dimethoate Dimethyldithiophosphorylacetic acid,o,o-, n- ... Fosfamid Methylcarbamoylmethyl-o,o-dimethyl phosphorodithioate,s- O,O-Dimethyl S-((methylcarbamoyl)methyl) ... Phosphamid	0.006 ug/L	105% Rec (SL)	12.10 % RSD (SL)	2.00 ug/L
Disulfoton(298-04-4) Disulfoton Disulphoton Disyston Disyston S Thiodemeton o,o-Diethyl-s-(2-eththioethyl)phosphorodithioate	0.009 ug/L	69% Rec (SL)	27.40 % RSD (SL)	2.00 ug/L
Disulfoton sulfone(2497-06-5) Disulfoton sulfone Disulfotonsulfone Disyston sulfone O,O-Diethyl S-(2-ethylsulfonylethyl) phosphoro O,O-Diethyl S-(2-ethylsulfonylethyl) phosphorodithioate	0.009 ug/L	116% Rec (SL)	15.17 % RSD (SL)	2.00 ug/L
Ethion(563-12-2) Bladan Diethion Ethion Ethodan Ethyl methylene phosphorodithioate Nialate O,O,O',O'-Tetraethyl S,S'-methylene bis( ... Tetraethyl S,S'-methylene bis(phosphorodithioate), O ... bis(S-(Diethoxyphosphinothioyl)mercapto)methane	0.004 ug/L	77% Rec (SL)	11.32 % RSD (SL)	2.00 ug/L
Ethion monoxon(17356-42-2) Ethion monooxon Ethion monoxon Monoethoxon Phosphorothioic acid, S-[[(diethoxyphosphinothioyl)thio]methyl] O,O-diethyl ester (9CI) S-[[(Diethoxyphosphinothioyl)thio]methyl] O,O-diethyl phosphorothioate	0.006 ug/L	102% Rec (SL)	12.48 % RSD (SL)	0.02 ug/L
Ethoprophos(13194-48-4) Ethoprop Ethoprophos Ethyl-s,s-dipropylphosphorodithioate,o- Mocap O-Ethyl S,S-dipropylphosphorodithioate Phosphorodithioic acid, O-ethyl S,S-dipropyl ester	0.004 ug/L	80% Rec (SL)	8.72 % RSD (SL)	2.00 ug/L
Ethyl parathion(56-38-2) DNTP Diethyl 4-nitrophenylphosphorothioate Diethyl-p-nitro phenyl mono thiophosphate Ethyl parathion Ethylparathion Niran O,O-Diethyl-O-p-nitrophenylphosphorothioate Parathion Parathion [phosphoric acid, O,O-diethyl-O-(4- ... Parathion ethyl Parathion, ethyl Parathion-ethyl Phosphorothioic acid, O,O-diethyl O-(4-nitroph Phosphorothioic acid, O,O-diethyl O-(4-nitrophenyl)ester	0.004 ug/L	76% Rec (SL)	10.59 % RSD (SL)	2.00 ug/L
Fenthion(55-38-9) Baycid Baytex Fenthion Mercaptophos O,O-Dimethyl O-(4-(methylthio)-m-tolyl) phosphorothioate O,O-Dimethyl-O-3-methyl-4-methylthiophenyl ... Tiguvon	0.005 ug/L	74% Rec (SL)	12.83 % RSD (SL)	2.00 ug/L
Fonofos(944-22-9) Difonate Dyfonate Dyphonate Fonofos O-ethyl S-phenyl ethylphosphonodithioate O-ethyl-s-phenyl ethyldithiophosphonate Phosphonodithioic acid, ethyl-, O-ethyl S-phenyl ester Stauffer N-2790	0.004 ug/L	77% Rec (SL)	9.36 % RSD (SL)	2.00 ug/L
Fonofos oxon(944-21-8) Dyfoxon Fonofos oxon Fonofoxon O-Ethyl S-phenyl ethanephosphonothioate O-Ethyl S-phenyl ethylphosphonothioate O-Ethyl S-phenyl ethylphosphonothiolate Phosphonothioic acid, ethyl-, O-ethyl S-phenyl ester (7CI,8CI,9CI)	0.007 ug/L	99% Rec (SL)	14.00 % RSD (SL)	0.02 ug/L
Malathion(121-75-5) Carbethoxy malathion Carbofos Cythion Dicarboethoxyethyl-o,o-dimethyl phosphorodithioate Malamar 50 Malathion Phosphothion Phosphothion, Sumitox Succinic acid, mercapto-, diethyl ester, S-est Sumitox	0.004 ug/L	90% Rec (SL)	8.82 % RSD (SL)	2.00 ug/L
Methidathion(950-37-8) Dimethyl phosphorodithioate, S-ester with 4-( ... Methidathion O,O-dimethyl phosphorodithioate, S- ... Phosphorodithioic acid, S-[(5-methoxy-2-oxo-1, Phosphorodithioic acid, S-[(5-methoxy-2-oxo-1,3,4- ... Supracide Surpacide Ultracide	0.006 ug/L	102% Rec (SL)	12.16 % RSD (SL)	2.00 ug/L
Methyl parathion(298-00-0) Dimethylparathion Metacide Metaphos Methyl parathion Nitrox-80 O,O-dimethyl O-p-nitrophenyl phosphorothioate Parathion methyl Parathion, Methyl Parathion-methyl	0.004 ug/L	89% Rec (SL)	8.57 % RSD (SL)	2.00 ug/L
O-ethyl-O-methyl-S-propylphosphorothioate(76960-87-7) O-ethyl-O-methyl-S-propylphosphorothioate	0.004 ug/L	73% Rec (SL)	11.59 % RSD (SL)	0.02 ug/L
Organophosphate pesticides(E-12873) Organophosphate pesticides Organophosphorus pesticides Pesticides, organophosphate	N/A	N/A	N/A
Phorate(298-02-2) AAstar O,O-Diethyl-S-(ethylthiomethyl)phosphorodithioate O,O-Diethyl-S-ethylmercaptomethyldithiophosphate Phorate Rampart Thimet	0.005 ug/L	68% Rec (SL)	13.42 % RSD (SL)	2.00 ug/L
Phorate oxygen analog(2600-69-3) Methanethiol, (ethylthio)-, S-ester with O,O-diethyl phosphorothioate (8CI) O,O-Diethyl S-(ethylthiomethyl) phosphorothioate Phorate oxon Phorate oxygen analog Phorate thiolate analog Phoratoxon Phosphorothioic acid, O,O-diethyl S-[(ethylthio)methyl] ester (6CI,7CI,8CI,9CI) Thimet oxon Thimet oxygen analog	0.006 ug/L	76% Rec (SL)	14.51 % RSD (SL)	0.02 ug/L
Profenofos(41198-08-7) CGA 15324 Curacron O-(4-Bromo-2-chlorophenyl) O-ethyl S-propyl phosphorothioate O-Ethyl S-propyl O-(2-chloro-4-bromophenyl)thiophosphate O-Ethyl-S-n-propyl-O-(2-chloro-4-bromophenyl)thiophosphate Polycron Profenofos Profenophos Selecron Tambo	0.005 ug/L	96% Rec (SL)	10.19 % RSD (SL)	0.02 ug/L
Propetamphos(31218-83-4) Propetamphos	0.003 ug/L	75% Rec (SL)	9.01 % RSD (SL)	2.00 ug/L
Sulfotepp(3689-24-5) Bladafum Dithion Dithiopyrophosphoric acid, tetraethyl ester O,O,O,O-Tetraethyl dithiopyrophosphate Sulfotepp TEDP Tetraethyldithiopyrophosphate Thiodiphosphoric acid ([(HO)2P(S)]2O), tetraethyl ester Thiodiphosphoric acid, tetraethyl ester Thiopyrophosphoric acid ([(HO)2P(S)]2O), tetra Thiopyrophosphoric acid ([(HO)2P(S)]2O), tetraethylester	0.003 ug/L	68% Rec (SL)	8.93 % RSD (SL)	2.00 ug/L
Sulprofos(35400-43-2) BAY-NTN 9306 Bayer NTN 9306 Bolstar Helothion Mercaprofos Mercaprophos NTN 9036 O-Ethyl O-(4-methylthiophenyl) S-propyl dithiophosphate Phosphorodithioic acid, O-ethyl O-[4-(methylthio)phenyl] S-propyl ester (9CI) Sulprofos	0.004 ug/L	73% Rec (SL)	12.20 % RSD (SL)	2.00 ug/L
Terbufos(13071-79-9) Counter Terbufos	0.004 ug/L	71% Rec (SL)	12.28 % RSD (SL)	2.00 ug/L
Tribufos(78-48-8) B 1,776 Butyl phosphorotrithioate Chemagro B 1776 DEF De-Green Deleaf defoliant Easy off-D FOS-FALL A Folex 6EC FosFall MERPHOSOXIDE (S,S,S-TRIBUTYL PHOSPHOROTRITHIOATE) Merphos oxide Ortho phosphate defoliant Phosphorotrithioic acid S,S,S-tributyl ester Phosphorotrithioic acid, S,S,S-tributyl ester (8CI,9CI) S,S,S-tributyl phosphorotrithioate TBPT TBTP Tribufos Tributylphosphorotrithioate	0.004 ug/L	80% Rec (SL)	10.26 % RSD (SL)	0.02 ug/L

Precision Descriptor Notes:	Samples of (1) reagent water, (2) surface water collected from the South Platte River, near Dartmouth Street and Platte River Drive, Denver, Colo., and (3) ground water collected from a domestic well in Evergreen, Colo., were used to test method performance. Eight samples of each water type were fortified with each compound at three different concentrations of 0.02, 0.05, and 0.5 ug/L. One sample for each water type was unfortified to determine any potential background contamination or interference in each matrix.
Detection Level Note:	The detection lebels for this method will be evaluated continuously using the long-term method detection procedure described by Childress and others, 1999.

Precision Descriptor Notes:

Samples of (1) reagent water, (2) surface water collected from the South Platte River, near Dartmouth Street and Platte River Drive, Denver, Colo., and (3) ground water collected from a domestic well in Evergreen, Colo., were used to test method performance. Eight samples of each water type were fortified with each compound at three different concentrations of 0.02, 0.05, and 0.5 ug/L. One sample for each water type was unfortified to determine any potential background contamination or interference in each matrix.

Detection Level Note:

The detection lebels for this method will be evaluated continuously using the long-term method detection procedure described by Childress and others, 1999.

Revision	PDF/Link
2003

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USGS-NWQL: O-3402-03: Organophosphate pesticides, Whole water, Gas Chromatography

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