EPA-OGWDW/TSC: 508.1:  Chlorinated Pesticides, Herbicides, and Organohalides in Water by GCECD

  • Summary
  • Analytes
  • Revision
  • Data and Sites
Official Method Name
Determination of Chlorinated Pesticides, Herbicides, and Organohalides by Liquid-Solid Extraction and Electron Capture Gas Chromatography
Current Revision
Revision 2.0, 1995
Gas Chromatography with Electron Capture Detection
Method Subcategory
Method Source
  Methods for the Determination of Organic Compounds in Drinking Water - Supplement III (EPA/600/R-95-131)
Brief Method Summary
A 1-L sample is passed through a liquid/solid extraction (LSE) disk or cartridge containing a solid inorganic matrix coated with a chemically bonded C-18 organic phase. The analytes (pesticides, herbicides, and organohalides) are eluted from the LSE disk or cartridge with small volumes of ethyl acetate and methylene chloride, and this eluate is concentrated by evaporation of some of the solvent. The concentrations of analytes are determined using a fused silica capillary column gas chromatography (GC) system equipped with an electron capture detector (ECD).

NOTE: CAS Numbers in NEMI for cis- and trans- permethrin differ from those in the method. The CAS Numbers in NEMI are the correct ones.
Scope and Application
This method determines 29 chlorinated pesticides, three herbicides, and four organohalides in drinking water, ground water, and drinking water in any treatment stage.
Applicable Concentration Range
Ranges differ for each analyte depending on matrix and instrumentation.

(A) Reagent contamination: Use high purity reagents.

(B) Contamination from sample carryover: Rinsing apparatus replacing syringes and injection port liners as needed can minimize contamination.

(C) Variable solvents: Use the same solvent for each analysis.

Quality Control Requirements

Initial demonstration of laboratory capability, followed by laboratory reagent blanks (LRBs), laboratory fortified blanks (LFBs), and laboratory fortified matrix samples. Additional quality control practices are recommended. Initial demonstration of capability is demonstrated by analysis of a minimum of four replicate LFBs containing each analyte of concern at a suggested concentration in the range of 0.01 - 0.5 ug/L. The mean accuracy should be 70% to 130% and the RSD should be less than 30%. A method detection limit (MDL) must also be determined for each analyte.

Sample Handling

Dechlorinate samples by adding 50 mg/L of sodium sulfite. Adjust the sample to a pH less than 2 by adding up to 4 mL of 6N HCl. Sample should be kept sealed from collection until analysis. Sampling equipment must not use plastic tubing, plastic gaskets, or any parts that may leach interfering analytes into the sample. Store samples at 4oC until analysis.

NOTE: Samples collected for cyanazine determination MUST NOT be dechlorinated or acidified when collected. Acidification and dechlorination must occur immediately prior to fortification with surrogate standard and extraction.

Maximum Holding Time

14 days.

Relative Cost
$201 to $400
Sample Preparation Methods