Residue levels of emamectin benzoate, imidacloprid and its major metabolites in cabbage from twelve regions in China and dietary risk assessment.

Abstract

A modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method combined with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established to investigate the residues of emamectin benzoate (EB), imidacloprid (IMI) and five IMI metabolites (IMI-olefin, IMI-urea, IMI-guanidine, 5-OH and 6-CNA) in cabbage. The average recoveries of the seven compounds in cabbage were 80%-102%, with relative standard deviations (RSDs) <8.0%. The limit of quantification (LOQ) for each compound was 0.01 mg kg -1 . Standardized residue tests were carried out in 12 areas of China under Good Agricultural Practice (GAP) conditions. A 10% EB-IMI microcapsule suspension was applied once with the high recommended dosage (18 g a.i. ha-1 ) on cabbage. The residues of EB (<0.01 mg kg-1 ), IMI (<0.016 mg kg-1 ) and the sum of IMI and its metabolites (<0.068 mg kg-1 ) in cabbage on the recommended preharvest interval (PHI) (7 d) were lower than the maximum residue limits (MRLs) in China. Based on residual data from fields, toxicology data, and Chinese dietary patterns, dietary risk assessments were conducted. Both the chronic risk quotients (25.2%-73.1%) and acute risk quotients (0.43%-1.57%) of EB and IMI were below 100%, indicating no unacceptable public health risk for different populations. This study provides guidance on the rational application of these insecticides in cabbage.