Matrix effect evaluation and method validation of organophosphorus pesticide residues in bell peppers (Capsicum annuum L.) by GC–MS determination

Abstract

ABSTRACT The matrix effects in bell pepper samples were studied. The simultaneous determination of six organophosphorus (OPPs) pesticides (chlorpyrifos, dichlorvos, disulfoton, ethoprophos, fenchlorphos, and prothiofos), by gas chromatography-mass spectrometry (GC/MS) method using sample preparation on QuEChERS-citrate, was developed and validated. Non-organic and organic bell peppers (Capsicum annuum L.) samples were analysed. Matrix-matched calibrations were established to correct matrix effect (ME) for quantification analysis of the six pesticides. All of the pesticides showed matrix-induced signal suppression, where chlorpyrifos and prothiofos were the pesticides that presented the most significant values, −65.54 and −65.31, respectively. The pesticides studied showed good linearity with correlation coefficient values higher than 0.99. The LODs ranged from 0.002 to 0.039 mg kg-1 and LOQs 0.006 to 0.130 mg kg-1. Only one sample of the bell pepper showed contamination with chlorpyrifos (0.177 mg.kg-1), corresponding to a value 17.7 times higher than the MRLs allowed for this crop by European Committee (EC) (0.010 mg.kg-1).