An enzyme-linked immunosorbent assay for the detection of esfenvalerate metabolites in human urine.

The pyrethroids are one of the most heavily used insecticide classes in the world. Sensitive and rapid analytical techniques are needed for assessments of human exposure to these compounds. Highly sensitive and selective ELISAs for glycine conjugates of esfenvalerate key metabolites phenoxybenzoic acid (PBA) and s-fenvalerate acid (sFA) were developed. Rabbits were immunized with either N-(3-phenoxybenzoyl)-4-amino-l-phenylalanine−fetuin or N-[(S)-4-chloro-2-(methylethyl)benzeneacetyl]-4-amino-l-phenylalanine−fetuin, and all sera were screened against numerous coating antigens. The antibodies with the least interference and best sensitivity were optimized and characterized. The I50s for sFA-glycine and PBA-glycine in buffer were found to be 0.40 ± 0.12 μg/L (1.47 ± 0.44 nmol/L) and 0.42 ± 0.18 μg/L (1.56 ± 0.67 nmol/L), respectively. Both assays exhibited high selectivity. Little or no cross reactivity to the parent compound and other metabolites was measured. The matrix effects of urine were investigated...