Determinationof4pesticideresiduesinhazelnutbymodifiedQuEChERSmethodusinghighperformanceliquidchromatography-tandemmassspectrometry

A multi-residue analysis method was developed for the determination of 4 pesticide (difenoconazole, propiconazole, thiamethoxam and acetamiprid) residues in hazelnut (including the nut and shell) based on a QuEChERS procedure using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The samples (hazelnut, and the hazelnut shell) were extracted with hexane-saturated acetonitrile and acetonitrile, and cleaned-up by florisil, GCB and PSA. The samples were separated by using an eclipse plus C₁₈ column connected to an electrospray ionization source in positive mode (ESI⁺), and analyzed by multiple reaction monitoring (MRM) mode. The external standard method was employed for the quantification. The results indicated that in the linear ranged from 0.01 to 2 mg/kg, all pesticides have a good linear relationship. At three spiked levels (0.01, 0.1 and 1 mg/kg), the intra-day average recoveries of 4 pesticides ranged from 79% to 111%, and the relative standard deviation (RSDs) ranged from 0.6% to 6.9% (n = 5), while the inter-day average recoveries ranged from 81% to 110%, and the RSDs ranged from 1.1% to 8.5% (n = 15). The limits of quantitation (LOQ) of 4 pesticides were all 0.01 mg/kg .This method is simple and highly efficient, which could be used for the routine analysis of the four pesticide residues in hazelnut．