Analysis of Pesticide Residues and Their Variability in Cabbage Using QuEChERS Extraction in Combination with LC-MS/MS

An analytical method for the simultaneous determination of residues of five insecticides and two fungicides in cabbage was developed and validated. Pesticide residues were extracted from the samples using QuEChERS extraction and the analysis was performed by liquid chromatography triple quadrupole mass spectrometry (LC-MS/MS). The performance of the method was investigated in terms of accuracy, precision, linearity, limit of detection (LOD), and limit of quantification (LOQ). The average recoveries ranged from 80 to 110 % with RSDr aecurrency sign 16 % for all the analytes at four fortification levels of 0.01, 0.05, 0.10, and 0.20 mg/kg. The LOD values ranged from 0.001 to 0.003 mg/kg, and the LOQ for all the analytes was set at 0.01 mg/kg. The linearity was very good and coefficient of determination was aeyen 0.997 for all the analytes when matrix-matched calibration standards were used. Matrix effect was estimated and it was found prominent for cabbage with cypermethrin and deltamethrin (+49 and +97 %, respectively). The method was applied very satisfactorily for the residue analysis of 132 fresh cabbage samples collected from different market places in Thessaloniki, Greece. Among the analyzed samples, 41 (31 % of the total no. of samples) had pesticide residues, of which, two had multiple pesticide residues and 39 had a single pesticide residue. Only one sample was found contaminated with deltamethrin at a level above the European Union maximum residue levels (EU-MRLs). Variability of pesticide residues originated from the samples of cabbage purchased from different market places of Thessaloniki in Greece were also estimated in this study. The estimated variability factors ranged from 1.00 to 6.75 and the average VFs was 5.00.