Immunoassay for Highly Water-Soluble Nitenpyram: Evaluating the Analytical Performance of an Easy-to-Use Screening Method for Agricultural Samples

Nitenpyram, a neonicotinoid insecticide, is highly soluble in water (>5.9 x 10(5) mg/L). Specifically examining its physicochemical properties, we have established a simple and rapid residue analytical method for nitenpyram using an enzyme-linked immunosorbent assay (ELISA) which requires no organic solvents. The I-50 value found with this ELISA method using a selective monoclonal antibody toward nitenpyram was 4.8 ng/mL. A hand-shaking method using water was applied for ELISA analysis to extract nitenpyram from fruiting vegetable samples of four kinds. Matrix effects caused by interfering substances coexisting in aqueous sample extracts were reduced by dilution with water. No problems were found in the analytical values obtained using ELISA. From analyses of nitenpyram-incurred fruiting vegetables with the proposed ELISA and the reference HPLC protocols, high mutual correlation was found, which suggests that the measurement accuracy of the proposed ELISA method is comparable to the reference HPLC procedure.