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DEVELOPMENT OF METHOD 535 FOR THE DETERMINATION OF CHLOROACETANILIDE AND OTHER ACETAMIDE HERBICIDE DEGRADATES IN DRINKING WATER BY SOLID PHASE EXTRACTION AND LIQUID CHROMATOGRAPHY/TANDEM MASS SPECTROMETRY
Citation:
SHOEMAKER, J. A. AND M. BASSETT. DEVELOPMENT OF METHOD 535 FOR THE DETERMINATION OF CHLOROACETANILIDE AND OTHER ACETAMIDE HERBICIDE DEGRADATES IN DRINKING WATER BY SOLID PHASE EXTRACTION AND LIQUID CHROMATOGRAPHY/TANDEM MASS SPECTROMETRY. JOURNAL OF AOAC INTERNATIONAL. AOAC International, Gaithersburg, MD, 89(1):201-209, (2006).
Impact/Purpose:
Develop an analytical method for the analysis of alachlor ESA and other acetanilide pesticide degradation products. The draft method, suitable for use in assessing occurrence of the pesticide degradation products as part of the Unregulated Contaminant Monitoring Rule (UCMR), will be delivered to OGWDW by February 2004. The final peer-reviewed method was delivered in September 2004.
Description:
EPA Method 535 has been developed in order to provide a method for the analysis of "Alachlor ESA and other acetanilide degradation products" which are listed on U.S. EPA's 1998 Drinking Water Contaminant Candidate List. Method 535 uses solid phase extraction with a nonporous graphitized carbon sorbent to extract the ethane sulfonic acid (ESA) and oxanilic acid (OA) degradates of propachlor, flufenacet, dimethenamid, alachlor, acetochlor and metolachlor from finished drinking water matrices. Separation and quantitation of the target analytes are achieved with liquid chromatography/tandem mass spectrometry (LC/MS/MS). Dimethachlor ESA and butachlor ESA were chosen during the method development as the surrogate and internal standard. Drinking water samples were dechlorinated with ammonium chloride without adversely affecting the analyte recoveries. Typical mean recoveries of 92-116% in deionized water and 89-116% in ground water were observed with relative standard deviations of <5%.