Dissipation behaviors of deltamethrin, emamectin benzoate and hexythiazox in grape under field conditions

The objective of this study was to evaluate the dissipation kinetics of deltamethrin, emamectin benzoate, and hexythiazox in grapes. The QuEChERS method was employed and validated for the precise determination of these three pesticides using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Excellent linearity was observed with regression coefficients exceeding 0.998. Notably, the limits of quantification (LOQ) were significantly lower than the maximum residue limits (MRLs) established for grapes by the European Union. The QuEChERS method l recovered 93.23% of the pesticides with an acceptable RSD of 5.35% (n = 180), demonstrating its suitability for quantifying them in grapes. Half-lives of deltamethrin, emamectin benzoate, and hexythiazox in grapes were 2.62-2.68 days, 8.15-7.30 days, and 3.24-4.01 days, respectively, for both single and double doses. Residues of all pesticides fell below the MRLs by the preharvest interval. This suggests that their application can be considered safe for grapes, ensuring both pest control and consumer safety.