Determination of 50 kinds of pesticide residues in vegetables and fruits by QuEChERS-liquid chromatography-tandem mass spectrometry
Objective After optimization of a quick,easy,cheap,effective,rugged and safe(QuEChERS)-based extraction pretreatment method combined with liquid chromatography-tandem mass spectrometry(LC-MS/MS)technology,a rapid multi-residue determination method was established for detecting 50 kinds of pesticides in vegetables and fruits.Methods The samples were extracted with acetonitrile,purified with 150 mg primary secondary amine(PSA),100 mg octadecyl bonded silica gel(C18)and 20 mg graphitized carbon black(GCB).A gradient elution was carried out on Acquity UPLC HSS T3 column with aqueous solution(2 mmol/L ammonium formate+0.01％formic acid)-methanol solution(2 mmol/L ammonium formate+0.01％formic acid)as the mobile phase.The determination was performed by multiple reaction monitoring(MRM)mode under electrospray positive ionization mode,and the quantification was performed by the matrix-matched external standard method.Results The results revealed that 50 kinds of pesticides showed good linearity in the concentration range of 0.125 ng/ml-500 ng/ml under the optimal experimental conditions,the linear correlation coefficients(r)were greater than 0.999,and the method detection limits were between 0.1μg/kg and 1.2μg/kg.The recoveries of added standard were 70.2％-112.6％,with the relative standard deviations(RSD)of 0.3％-8.6％in vegetables and fruits.The method established was used to determine 60 vegetable samples,and 6 kinds of pesticides like thiamethoxam,carbendazim and propiconazole were detected in 14 samples,with the concentrations ranging from 0.005,45mg/kg to 0.278mg/kg.Imidacloprid,thiamethoxam and acetamiprid were detected in 4 of 20 fruit samples,with the concentrations ranging from 0.017,2mg/kg to 0.059,6mg/kg.Conclusion The method has fast and simple pretreatment,low solvent consumption,high sensitivity,and accurate qualitative and quantitative analysis.It is suitable for the rapid screening of pesticide multi-residues in large quantities of vegetable and fruit samples.
quick,easy,cheap,effective,rugged and safe-based extractionliquid chromatography-tandem mass spectrometryvegetablefruitpesticide residue
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