Method 8141B Water

Organophosphorus Compounds by Gas Chromatography


This method is for the determination organophosphorous compounds (pesticides/herbicides) from aqueous matrices.  The sample is extracted at a neutral pH using either Method 3510 (separatory funnel), Method 3520 (continuous liquid-liquid extraction), Method 3535 (solid-phase extraction), or other appropriate technique. The extract can be cleaned up if necessary.  Cleanups that may be used include alumina (Method 3610), Florisil® (Method 3620), silica gel (Method 3630), gel permeation chromatography (Method 3640), and sulfur (Method 3660), or other appropriate technique.  The extract is analyzed by GC/FPD (flame photometric detector) or GC/NPD (nitrogen-phosphorous detector).  A second column confirmation is required for any positive detects.  GC/MS can be used if the concentration in the sample is high enough.

NOTE:  This method updates and replaces Methods 8140, 8141 and 8141A.


(EPA SW-846)

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Method Data

Hold Times, Preservatives, Preps, Collection, Analytical & Documentation
Holding Time:   7 days from sample collection to extraction and 40 days from extraction to analysis.
Preservatives:   Adjust pH of 5 to 8 using NaOH or H2SO4 as soon as possible after sample collection. Chill and ship samples at 4°C and store at 6°C until extraction.
Required Preps:   1L Amber glass bottle with Teflon-lined lid
Collection Method:   Grab sampling, SW-846 Chapter 4, Section 4.1
Analytical Methodology:   GC/NPD or GC/FPD
Documentation:   8141B

Analyte List*

Analyte Formula CAS Number Detection Limit
Pebulate
C10H21NOS
1114-71-2
1
 µg/L
Fensulfothion
C11H17O4PS2
115-90-2
1
 µg/L
Malathion
C10H19O6PS2
121-75-5
1
 µg/L
Fenitrothion
C9H12NO5PS
122-14-5
1
 µg/L
Simazine
C7H12ClN5
122-34-9
1
 µg/L
Propham
C10H13NO2
122-42-9
1
 µg/L
Terbufos
C9H21O2PS3
13071-79-9
1
 µg/L
Phosphamidon
C10H19ClNO5P
13171-21-6
1
 µg/L
Ethoprop
C8H19O2PS2
13194-48-4
1
 µg/L
Dicrotophos
C8H16NO5P
141-66-2
1
 µg/L
Merphos
C12H27PS3
150-50-5
1
 µg/L
Atrazine
C8H14ClN5
1912-24-9
1
 µg/L
Butylate
C11H23NOS
2008-41-5
1
 µg/L
Methiocarb (Mesurol)
C11H15NO2S
2032-65-7
1
 µg/L
EPN
C14H14NO4PS
2104-64-5
1
 µg/L
Leptophos
C13H10BrCl2O2PS
21609-90-5
1
 µg/L
TEPP (Tetraethyl pyrophosphate)
C8H20O5P2
21646-99-1
1
 µg/L
Molinate
C9H17NOS
2212-67-1
1
 µg/L
Tetrachlorvinphos
C10H9Cl4O4P
22248-79-9
1
 µg/L
Bendiocarb
C11H13NO4
22781-23-3
1
 µg/L
Triallate
C10H16Cl3NOS
2303-17-5
1
 µg/L
Azinphos-ethyl
C12H16N3O3PS2
2642-71-9
1
 µg/L
Chlorpyrifos (Dursban)
C9H11Cl3NO3PS
2921-88-2
1
 µg/L
Thionazin (Zinophos)
C8H13N2O3PS
297-97-2
1
 µg/L
Methyl parathion
C8H10NO5PS
298-00-0
1
 µg/L
Phorate
C7H17O2PS3
298-02-2
1
 µg/L
Disulfoton
C8H19O2PS3
298-04-4
1
 µg/L
Ronnel
C8H8Cl3O3PS
299-84-3
1
 µg/L
Naled (Dibrom)
C4H7Br2Cl2O4P
300-76-5
1
 µg/L
Aspon
C12H28O5P2S2
3244-90-4
1
 µg/L
Trichloronate
C10H12Cl3O2PS
327-98-0
1
 µg/L
Diazinon
C12H21N2O3PS
333-41-5
1
 µg/L
Tokuthion
C11H15Cl2O2PS2
34643-46-4
1
 µg/L
Sulprofos (Bolstar)
C12H19O2PS3
35400-43-2
1
 µg/L
Sulfotep
C8H20O5P2S2
3689-24-5
1
 µg/L
Chlorfenvinphos
C12H14Cl3O4P
470-90-6
1
 µg/L
Trichlorfon
C4H8Cl3O4P
52-68-6
1
 µg/L
Famphur
C10H16NO5PS2
52-85-7
1
 µg/L
Fenthion (Baytex)
C10H15O3PS2
55-38-9
1
 µg/L
Chlorpyrifos-methyl
C7H7Cl3NO3PS
5598-13-0
1
 µg/L
Ethion
C9H22O4P2S4
563-12-2
1
 µg/L
Ethyl parathion
C10H14NO5PS
56-38-2
1
 µg/L
Coumaphos (Co-Ral)
C14H16ClO5PS
56-72-4
1
 µg/L
Dimethoate
C5H12NO3PS2
60-51-5
1
 µg/L
Dichlorvos
C4H7Cl2O4P
62-73-7
1
 µg/L
Hexamethylphosphoramide (HMPA)
C6H18N3OP
680-31-9
1
 µg/L
Monocrotophos
C7H14NO5P
6923-22-4
1
 µg/L
Phosmet
C11H12NO4PS2
732-11-6
1
 µg/L
EPTC
C9H19NOS
759-94-4
1
 µg/L
Crotoxyphos (Ciodrin)
C14H19O6P
7700-17-6
1
 µg/L
Mevinphos (Phosdrin)
C7H13O6P
7786-34-7
1
 µg/L
Tri-o-cresyl phosphate (TOCP)
C21H21O4P
78-30-8
1
 µg/L
Dioxathion
C12H26O6P2S4
78-34-2
1
 µg/L
Carbophenothion
C11H16ClO2PS3
786-19-6
1
 µg/L
Demeton
C8H19O3PS2
8065-48-3
1
 µg/L
Azinphos-methyl (Guthion)
C10H12N3O3PS2
86-50-0
1
 µg/L
Fonofos (Dyfonate)
C10H15OPS2
944-22-9
1
 µg/L
o-Phenylenediamine
C6H8N2
95-54-5
1
 µg/L
Dichlofenthion
C10H13Cl2O3PS
97-17-6
1
 µg/L
Prosulfocarb
C14H21NOS
52888-80-9
1
 µg/L

* The analytes and detection limits listed for each method represent the typical detection limits and analytes reported for that particular method. Keep in mind that analyte lists may vary from laboratory to laboratory. Detection limits may also vary from lab to lab and are dependent upon the sample size, matrix, and any interferences that may be present in the sample.