Enzyme immunoassay for the determination of the insecticide fenoxycarb

A very selective polyclonal antiserum against ethyl 2-(4-phenoxyphenoxy)ethylcarbamate (fenoxycarb) was raised in a rabbit by immunization with a 2-(4-phenoxyphenoxy)ethanol hemisuccinate-bovine serum albumin conjugate, The antiserum was used to carry out a heterogeneous competitive enzyme immunoassay for the selective quantification of fenoxycarb at the ng ml-l level. The effects on the assay performance of different pH and ionic strength values, as well as the presence of methanol as organic modifier in the diluent buffer formulation, were studied. The optimized calibration curve showed a sensitivity of 0.42 ng ml(-1). The assay selectivity was found to be good, with no significant cross-reactivity towards fenoxycarb-related pesticides such as chloroxuron, cypermethrin, diclofop, p,p'-DDT, difenoxuron, permethrin and pyriproxyfen.