EPA-OGWDW/TSC: 551.1:  Chlorinated Compounds in Water Using GC-ECD

  • Summary
  • Analytes
  • Revision
  • Data and Sites
Official Method Name
Determination of Chlorinated Disinfection Byproducts, Chlorinated Solvents, and Halogenated Pesticides/Herbicides in Drinking Water by Liquid/Liquid Extraction and Gas Chromatography with Electron Capture Detection
Current Revision
Revision 1.0, 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 50-mL sample is extracted with 3-mL of MTBE or 5-mL of pentane. The concentrations of compounds in the extract are measured using a fused silica capillary column gas chromatography (GC) system equipped a linearized electron capture detector (ECD).
Scope and Application
This method determines certain chlorinated or halogenated compounds (disinfection byproducts, pesticides, herbicides, and solvents) in finished drinking water, drinking water during intermediate stages of treatment, and raw source water.
Applicable Concentration Range
Ranges differ for each analyte.
(A) Glassware contamination: Thoroughly clean glassware, including baking or solvent rinse.

(B) Solvent contamination: Use high purity solvents, and test solvents to prevent contamination: Contamination of MTBE and pentane with chlorinated solvents (common occurrence) can be reduced by double distillation.

(C) Extracted interferences: Interference from extracted non-target compounds, with retention times similar to target compounds, can be reduced using confirmation analysis.

(D) Endrin degradation: The splitless injector may cause endrin degradation. Endrin can break down by reacting with the active sites on the port sleeve.

(E) Phthalate interference: An unknown interference (probably phthalates) appears in retention windows of metribuzin, alachlor, cyanazine, and heptachlor. Seal containers and avoid sample contact with plastics.

Quality Control Requirements
Laboratory performance check standard, initial demonstration of laboratory capability, method detection limit (MDL) determination, analysis of laboratory reagent blanks (LRBs), continuing calibration check standard, laboratory fortified sample matrices, field duplicates, and monitoring surrogate and/or internal standard peak response in each sample and blank. Additional QC practices may be added.
Sample Handling
Two sets of 60-mL vials must be prepared for sampling: one set for all target analytes except chloral hydrate with 100 mg/L of ammonium chloride as a dechlorinating agent and one set for the analysis of chloral hydrate using 100 mg/L of sodium sulfite as the dechlorinating agent. Ammonium chloride must also be used as the dechlorinating agent if samples are to be analyzed for haloacetonitriles, 1,1-dichloro-2-propanone, 1,1,1-trichloro-2-propanone, and chloropicrin.

All samples should be collected in duplicate. Overfill all bottles, making sure to leave no bubbles or headspace. Store samples at 4oC until analysis.

Maximum Holding Time
14 days; extracts within 14 days.
Relative Cost
$201 to $400
Sample Preparation Methods