Clothianidin residues in green bean, pepper and watermelon crops and dietary exposure evaluation based on dispersive liquid-liquid microextraction and LC–MS/MS

Abstract

We developed an analytical method for quantifying clothianidin residues in green bean, pepper and watermelon crops using dispersive liquid-liquid microextraction (DLLME) and liquid chromatography-tandem mass spectrometry; this method was more rapid, sensitive and simple than QuEChERS sample preparation. Method validation indicated that the recovery for clothianidin was 80.8–93.1%, intra-day and inter-day repeatability ranged from 3.32 to 6.11% and 7.77 to 14.74%, respectively, limits of detection ranged from 0.64 to 0.74 µg/kg, and limits of quantification were 2.13–2.47 µg/kg. Matrix-matched calibration was used to compensate for matrix effects. Following application of the recommended dose in field trials, clothianidin dissipation followed first-order kinetics with half-lives of 1.9, 2.07, and 1.87 days in green bean, pepper, and watermelon crops; respective waiting periods of 5.76, 6.18, and 7.87 days after application are suggested for safe consumption. This study indicates the application of clothianidin presents no significant health risk to Egyptian consumers.