The research on enzyme-linked immunosorbent assay for fenvalerate

An indirectly competitive enzyme-linked immunosorbent assay (ic-ELISA) was developed for the quantitative detection of fenvalerate. The hapten FVa (α-carboxy-3-phenoxyphenyl-2-(4-chloro-phenyl)-3-methyl-butyrate) and FVb (N-2-(carboxybutyl)carbamoyl-3-phenoxyphenyl-2-(4-chlorophenyl)-3-methylbutyrate) for the fenvalerate were prepared starting from 2-(4-chlorophenyl)-3-methyl-butyric acid and α-cyano-3-phenoxyhenzyl-benzyl alcohol. The hapten FVa was conjugated to ovalbumin (OVA) to form the coating antigen (FVa-OVA); the hapten FVb was conjugated to bovine serum albumin (BSA) to form the immunogen (FVb-BSA). The rabbits were immunised by conjugate of FVb-BSA, and titres of anti-fenvalerate serum (1.28×104) was determined by non-competitive indirect ELISA. After optimisation of the ic-ELISA, such as pH values, ionic strengths, concentrations of methanol, pH 7.5, phosphate-buffered saline of 0.3 M Na+ and 30% methanol were determined to optimum assay condition. The medium inhibitory concentration (IC50) for fenvalerate was (1.19±0.09) mg/L, and limit of detection (LOD) was (0.017±0.002) mg/L. Pyrethroids, such as fenpropathrin, cyhalothrin, permethrin, cypermethrin, deltamethrin and bifenthrin did not cross-react significantly in this assay.