Stereoselectivity of an enzyme-linked, immunosorbent assay for S-bioallethrin

Abstract

A sensitive, specific, indirect and competitive enzyme-linked immunosorbent assay (ELISA) based on a polyclonal antibody (PcAb) for S-bioallethrin was developed. The hapten-bovine serum albumin (BSA) conjugate was used as an immunogen while the hapten-ovalbumin (OVA) conjugate was applied as a coating antigen. An anti-S-bioallethrin PcAb was obtained from immunized New Zealand white rabbits, and an ELISA for S-bioallethrin was developed. The inhibition standard curve of S-bioallethrin was obtained using optimized conditions (40% methanol, 0.5 mol L⁻¹Na⁺, pH 6.5). The half-maximal inhibition concentration (IC₅₀) was 0.089 μg mL⁻¹, and the limit of detection (LOD, IC₁₀) was 0.0025 μg mL⁻¹. Very low cross-reactivity (CR) was found for allethrin and other pyrethroids. The CR for the stereoisomer demonstrates that the antibody has notable stereoselectivity for S-bioallethrin. Water and dust spiked with S-bioallethrin were analyzed by ELISA and acceptable recovery rates, 90.7% to 111.7%, were obtained. The ELISA results were confirmed by gas chromatography/electron capture detection (GC-ECD) and the proposed ELISA could be a highly sensitive, stereoselective, simple, rapid and inexpensive method for the detection of S-bioallethrin in environmental samples.