Hapten design in the development of competitive enyme-linked immunosorbent assays for genotoxic metabolites of alachlor.

Abstract

The acetanilide compounds 2-chloro-2',6'-diethylacetanilide (CDA) and 2-hydroxy-2',6'-diethylacetanilide (HDA) are environmental degradative products of the chloroacetanilide herbicide alachlor. CDA, HDA, and alachlor are ground and surface water contaminants. CDA and HDA are genotoxic in bacterial and mammalian test systems. This paper reports hapten design in the development of two competitive enzyme-linked immunosorbent assays (cELISA) for the detection of CDA and HDA. Chloroacetanilide herbicides and other alachlor metabolites that may be present in environmental samples do not cross-react with the detection of CDA and HDA. Solid-phase extraction of CDA and HDA residues from aqueous samples results in a 1000-fold concentration factor, resulting in an effective detection limit of 15 pg/mL for both assays. The specificity of the cELISAs required preservation of the degree of substitution of the acetanilide moiety in the hapten design. The hapten synthesis strategies are suitable for metabolites of other chloroacetanilide herbicides (i.e., acetochlor, butachlor, metolachlor, and propachlor).