Application of enzyme-linked immunosorbent assay for quantification of the insecticides imidacloprid and thiamethoxam in honey samples

An enzyme-linked immunosorbent assay (ELISA) was used for the determination of residues of imidacloprid and thiamethoxam insecticides in honey after simple dilution of the samples without either extraction or cleanup. The ELISA enabled accurate determination of imidacloprid and thiamethoxam down to limits of 20 and 5 ng g-1 in honey, respectively. Average recoveries of imidacloprid and thiamethoxam from the fortified honey samples were 90-120 and 96-122%, and coefficients of variation ranged 5-12 and 3-15%, respectively. The results from the ELISA agreed well with those by liquid chromatography-mass spectrometry (LC-MS) for the insecticide-spiked samples, with a correlation coefficient (r2) of 0.96 and a regression coefficient (slope) of 1.03. The results indicate that ELISA is a suitable tool for the quantification of imidacloprid and thiamethoxam in honey.