The optimization and establishment of QuEChERS-UPLC-MS/MS method for simultaneously detecting various kinds of pesticides residues in fruits and vegetables

Objectives: The quality safety supervision and test of agricultural products urgently need a very excellent analytical method with simultaneously detecting many components in order to assess, prevent and control pesticide residues. Methods: In this research, three fruits and three vegetables produced in Shanghai were selected as the materials, 54 pesticide residues were detected with the ultra-high performance liquid chromatography-tandem mass spectrometric (UPLC MS/MS) method on the basis of optimized QuEChERS method according to different materials properties. Results: The results showed that: all samples were directly extracted by acetonitrile containing 1% (v/v) acetic acid; complex matrix samples were purified by a mixed sorbent of 300 mg MgSO4 + 100 mg PSA + 100 mg C18 + 0.01 g Carb, general matrix samples didn't add Carb, simple matrix samples such as watermelon directly filmed; Chromatographic column was ZORBAX Eclipse Plus-C18 column (3.0 mm x 150 mm, 3.5 mu m) at 40 degrees C, the methanol-water of mobile phase at a flow rate of 0.45 mL/min by a gradient elution contained 0.1% formic acid and 5 mmol/L ammonium acetate and the injection volume was 1 mu L. With switching electrospray ion source polarity, [M - H](-) and high sensitive [M + Na](+) were respectively the precursor ions of eight pesticides and avermectin, [M+Fl] (+) was those of the else 45 pesticides. The detection parameters of multi-reactions monitoring (MRM) with simultaneously positive and negative ions (electron multiplier voltage was 200 V) scanning were set as follows: the 310.3 kPa of nebulizer pressure, the 300 degrees C of drying gas temperature, the 7 mu L/min of drying gas flow, the 3000 V and 3500 V of respectively capillary positive and negative voltage. With the optimized method, the calibration curves of 54 pesticides were better linear in 15-500 mu/kg (r >= 0.988), the average adding standard recovery rates of 54 pesticides were 73.2%-134.3% except pymetrozine and cyromazine with the relative standard deviations (RSD) of 1.0%-13.8%; the limit of detection (LOD) under three times signal-to-noise ratio (S/N) and limit of quantitative (LOQ) under 10 times S/N were respectively confirmed 0.003-2.000 mu/kg and 0.01-6.6714/kg. Conclusions: The results demonstrated that the optimized QuEChERS-UPLC MS/MS method was a simple, rapid, sensitive, accurate, efficient, economical and safe method that simultaneously detected multiple pesticide residues through one time sample treatment; It had some advantages such as more pesticides per detection, simple and convenient pretreatment and less solvent dosage to be suitable for the quick high-throughput quantitative screening and confirmation of pesticide residues in fruits and vegetables.