Determination of the Cross-Reactivities of Immunoassays: Effect of Common Cross-Reactants for Chlorpyrifos-ethyl in Water Matrices Using Magnetic Particle-Based ELISA

摘要

A novel approach to assess the cross-reactivity of immunoassays in the simultaneous presence of potential cross-reactant analytes was reported. The magnetic particle-based ELISA for chlorpyrifos-ethyl was used as a model assay in various water matrices (distilled, ground, and estuarine) in the presence of other orga-nophosphorus pesticides commonly applied: chlo-rpyrifos-methyl, pyridafenthion, diazinon, fenitrothion, azinphos-ethyl, dichlorvos, temephos, and fenthion. The interferences were studied at a fixed concentration of 0.5 μg/L chlorpyrifos-ethyl and varying concentrations of the common cross-reactahts from 0.05 to 1000 μg/L. The method for determining cross-reactivities gave much lower values (25-50%) as compared to conventional methods. A slight variation (< 3%) on the cross-reactivity values was detected according to the water type used.