Development of a class-specific immunoassay for the type I pyrethroid insecticides

A general enzyme-linked immunosorbent assay was developed for the type I pyrethroid insecticides, such as permethrin, phenothrin, resmethrin and bioresmethrin. Polyclonal antibodies were generated by immunizing with a permethrin derivative, 2,2-dimethyl-3-(5′-carboxy-pent-1′-en-yl)cyclopropanecarboxylic acid-(3-phenoxybenzyl)ester conjugated with thyroglobulin, bovine serum albumin or ovalbumin. Antisera were screened against eight different coating antigens. The antibody-antigen combination with the lowest background, and highest sensitivity for permethrin was further optimized and tested for solvent and detergent tolerance. The I₅₀'s of the optimized immunoassay were 30 μg/l for permethrin and 20 μg/l for phenothrin, respectively. No cross-reactivities were measured to the type II pyrethroids, such as esfenvalerate, cyfluthrin, cypermethrin, deltamethrin, fenvalerate and fluvalinate. This assay can be used in monitoring studies to distinguish between types I and II pyrethroids.