Sensitive detection of thiacloprid in environmental and food samples by enhanced chemiluminescent enzyme immunoassay

Abstract

A fast and sensitive enhanced chemiluminescent enzyme immunoassay (ECL-EIA) was developed based on horseradish peroxidase detected with a luminol-based substrate for neonicotinoid insecticide thiacloprid in environmental and food samples. Toward this goal, a variety conditions of chemiluminescent substrate solution including the reacting buffer, the concentrations of p-iodophenol, luminol and H₂O₂ were optimized. Under the optimal conditions, the sensitivity (the 50% inhibitory concentration value) was 1.80 ng mL⁻¹. The ECL-EIA was 5.5 times more sensitive compared to the colorimetric-EIA. The average recoveries of thiacloprid from ten spiked samples were estimated to range from 79.7 to 119%, with relative standard deviations of 4.2 to 11.2%. The dissipation of thiacloprid applied to real tomato samples was monitored with the ECL-EIA and HPLC methods. The ECL-EIA results agreed well with the HPLC results (R² = 0.993). These results suggested that the thiacloprid in the samples could be simply, rapidly and accurately detected by ECL-EIA.