In this study, a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method, optimized by a 23 full factorial design, was developed for the determination of 72 pesticides in plant parts of carrot, corn, melon, rice, soy, silage, tobacco, cassava, lettuce and wheat by ultra-high-performance liquid chromatographic tandem mass spectrometry (UHPLC-MS/MS). Considering the complexity of these matrices and the need of use calibration in matrix, a new calibration approach based on single level standard addition in the sample (SLSAS) was proposed in this work and compared with the matrix-matched calibration (MMC), the procedural standard calibration (PSC) and the diluted standard addition calibration (DSAC). All approaches presented satisfactory validation parameters with recoveries from 70 to 120% and relative standard deviations≤20%. SLSAS was the most practical from the evaluated approaches and proved to be an effective way of calibration. Method limit of detection were between 4.8 and 48μgkg-1 and limit of quantification were from 16 to 160μgkg-1. Method application to different kinds of plants found residues of 20 pesticides that were quantified with z-scores values≤2 in comparison with other calibration approaches. The proposed QuEChERS method combined with UHPLC-MS/MS analysis and using an easy and effective calibration procedure presented satisfactory results for pesticide residues determination in different crop plants and is a good alternative for routine analysis.
Keywords: Pesticides; Plants; QuEChERS; Standard addition; UHPLC–MS/MS.
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