Residue behavior and risk assessment of cymoxanil in grape under field conditions and survey of market samples in Guangzhou.

A simple and fast method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for cymoxanil residue analysis in grape. Sample preparation based on solid-liquid extraction was optimized without using adsorbent for purification. Recoveries were 79.8-109.5% with relative standard deviations (RSDs) of 2.5-9.4% at fortified levels from 0.001 to 0.50 mg/kg. The limit of detection (LOD) was 0.3 μg/kg. Field trials were conducted to explore the dissipation and terminal residue behavior of cymoxanil in grape. Results showed that the half-lives of cymoxanil were from 0.5 to 0.7 days. Terminal residues were from below the limit of quantification (LOQ) to 0.363 mg/kg. Dietary exposure risk assessment revealed that the risk quotients (RQs) were much less than 1. It was concluded that cymoxanil in grape raised negligible concerns to human health under field conditions. Sixty grape samples from Guangzhou market were found to be free of cymoxanil. The proposed study would provide reference for appropriate use of cymoxanil in grape planting in China.