Methods of Analysis by the U.S. Geological Survey
Organic Geochemistry Research Group-Determination
of Chloroacetanilide Herbicide Metabolites in Water Using High-Performance Liquid Chromatography-Diode Array Detection and High-Performance Liquid Chromatography/Mass Spectrometry

By L.R. Zimmerman, K.A. Hostetler, and E.M. Thurman

Abstract

Analytical methods using high-performance liquid chromatography-diode array detection (HPLC-DAD) and high-performance liquid chromatography/mass spectrometry (HPLC/MS) were developed for the analysis of the following chloroacetanilide herbicide metabolites in water: acetochlor ethanesulfonic acid (ESA), acetochlor oxanilic acid (OXA), alachlor ESA, alachlor OXA, metolachlor ESA, and metolachlor OXA. Good precision and accuracy were demonstrated for both the HPLC-DAD and HPLC/MS methods in reagent water, surface water, and ground water. The mean HPLC-DAD recoveries of the chloroacetanilide herbicide metabolites from water samples spiked at 0.25, 0.50, and 2.0 mg/L (micrograms per liter) ranged from 84 to 112 percent, with relative standard deviations of 18 percent or less. The mean HPLC/MS recoveries of the metabolites from water samples spiked at 0.05, 0.20, and 2.0 mg/L ranged from 81 to 125 percent, with relative standard deviations of 20 percent or less. The limit of quantitation (LOQ) for all metabolites using the HPLC-DAD method was 0.20 mg/L, whereas the LOQ using the HPLC/MS method was 0.05 mg/L. These metabolite-determination methods are valuable for acquiring information about water quality and the fate and transport of the parent chloroacetanilide herbicides in water.

Additional information about the Organic Geochemistry Research Laboratory can be found at: http://ks.water.usgs.gov/Kansas/studies/reslab/

Zimmerman, L.R., Hostetler, K.A., and Thurman, E.M., Methods of Analysis by the U.S. Geological Survey Organic Geochemistry Research Group-Determination of Chloroacetanilide Herbicide Metabolites in Water Using High-Performance Liquid Chromatography-Diode Array Detection and High-Performance Liquid Chromatography/Mass Spectrometry: U.S. Geological Survey Open-File Report 00-182, 30 p.

To request a paper copy of this report, email: GS-W-KS_info@usgs.gov