Quantitative Determination of Neonicotinoid Insecticide Thiamethoxam in Agricultural Samples: a Comparative Verification Between High-Performance Liquid Chromatography and Monoclonal Antibody-Based Immunoassay

Abstract

This work describes the analytical performance of the newly developed kit-based enzyme-linked immunosorbent assay (ELISA) for neonicotinoid insecticide thiamethoxam to effectively exploit as a rapid and simple detection system for pesticide residue on the scenes of the agricultural production and distribution. The ELISA represents the satisfactory analytical characteristics (IC50 value, 0.72 ng mL−1; limit of detection, 0.1 ng mL−1) to detect thiamethoxam at the maximum residue limits or thereabout in samples. For the ELISA analysis, methanol that showed the lowest influence on the assay performance was selected as the best extractant, and the final concentration in the well could be up to 5 % (v/v) without any negative influence on the ELISA. Dilution of sample extracts with water was effective in eliminating matrix interference. Average recoveries from thiamethoxam-spiked agricultural samples were >88 % using a rapid and simple extraction method with hand shaking for 5 min. Analytical results obtained from the ELISA were comparable to those obtained from the conventional HPLC method. These findings strongly indicate that the proposed kit-based ELISA for determination of thiamethoxam residue in agricultural samples may be routinely employed as a rapid, simple, and quantitative preliminary screening method for the monitoring of safety of agricultural products.