Simultaneous multiresidue analysis of 41 pesticide residues in cooked foodstuff using QuEChERS: Comparison with classical method

► Most of the pesticides exhibited similar recovery rates in tests of both methods. ► Low recoveries were evidenced for some pesticides when classical method was used. ► QuEChERS method is simple and exhibits acceptable level of sensitivity and accuracy. The principal objective of this study was to develop a simple multiresidue method involving a quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction method for the identification and quantification of 41 pesticide residues in cooked foodstuffs including cooked potatoes, radishes, and rice using GC-μECD. The analytes were subsequently confirmed via GC–MS. The results were then compared using the classical method established by the KFDA. The quantitation of individual pesticides was based on matrix-matched calibration curves with a correlation coefficient in excess of 0.993 for the 41 pesticides selected herein. Using QuEChERS, the mean recoveries ranged between 68.6 and 130.0% for the majority of the tested pesticides; however, the classical method exhibited low recoveries for dichlofluanid, tetraconazole, oxadixyl, fenbuconazloe, and paclobutrazol. After QuEChERS, the LODs and LOQs ranged between 0.004 and 0.3μg/kg and 0.0125 and 1.0μg/kg, respectively. The proposed method was applied successfully to determine the residue levels in cooked foodstuffs, and none of the samples contained detectable amounts of pesticide residues.