Development and Evaluation of an Enzyme-Linked Immunosorbent Assay for the Determination of Thiacloprid in Agricultural Samples

An enzyme-linked immunosorbent assay (ELISA) was developed based on a polyclonal antibody for the analysis of thiacloprid in agricultural samples. Thiacloprid hapten was synthesized and conjugated to bovine serum albumin to produce an immunogen and ovalbumin to produce a coating antigen. Polyclonal antibodies were obtained from immunized New Zealand white rabbits. Under optimal conditions (5 % methanol, 0.1 mol/L Na+, pH 5.5), the ELISA showed a 50 % inhibitory concentration (IC50) value of 0.01 mg/L and a limit of detection (IC10) of 0.47 mu g/L. No obvious cross-reaction with the other structural analogs of neonicotinoid insecticides showed that the polyclonal antibodies had a high specificity for thiacloprid. The average recoveries from spiked water, soil, pear, and tomato were in the range of 80 to 119 %. The results of the ELISA were confirmed by high-performance liquid chromatography, and the correlation of the results from the two methods had a high correlation coefficient of 0.99 (n = 3) in spiked samples (soil, pear, and tomato). The proposed ELISA could successfully be applied to the determination of thiacloprid residues in agricultural samples.