Determination of Multiple Pesticide Residues in Eggplant with Liquid Chromatography-Mass Spectrometry

Abstract

A simple and efficient multiple pesticide residue analytical method using quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction and liquid chromatography triple quadrupole-mass spectrometry was developed and validated for the determination of ten insecticides and three fungicides in eggplant. The method was validated by evaluating the accuracy, precision, linearity, limit of detection, and limit of quantification. The average recoveries of the selected pesticides ranged from 71.8 to 112 % with precision in case of repeatability (RSD_r) ≤16.2 % in four fortification levels of 0.01, 0.05, 0.1, and 0.5 mg/kg. The linearity was ≥0.997 for all of the selected pesticides with matrix-matched calibration standards. The limit of detection (LOD) ranged from 0.001 to 0.003 mg/kg and the limit of quantification (LOQ) was 0.01 mg/kg, which was lower than the Maximum residue levels set by European Union (EU-MRLs). Matrix effect was also evaluated, and it was found that thiamethoxam, cypermethrin, and deltamethrin had pronounced matrix effect (−69, +57, and +93 %, respectively). This method was applied for the residue analysis of 72 fresh eggplant fruit samples collected from different market places in Thessaloniki, Greece. Among the 72 analyzed samples, 34 (47 % of the total no. of samples) had pesticide residues, of which, 5 had multiple pesticide residues and 29 had single pesticide residue. Only one sample contained residue above the EU-MRLs.