Simultaneous determination of 82 pesticides in Viola yedoensis Makino by QuEChERS-ultra high performance liquid chromatography-tandem mass spectrometry

Rapid screening and quantitative determination of 82 pesticides with QuEChERS were achieved by ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). In the orthogonal experiments, 9 combinations were designed to investigate the effect of 4 different adsorbents (PSA, C₁₈, GCB and SiO₂) on the purification performance of Viola yedoensis Makino.V. yedoensis samples were pretreated by PSA 800 mg, C₁₈ 3 200 mg, GCB 1 600 mg and SiO₂ 1 600 mg. The chromatographic separation of 82 pesticides was achieved by phenmenex DOD-4475-AN C₁₈ column using acetonitrile/water (0.1% formic acid and 10 mmol/L ammonium formate) in the gradient elution mode. Standard curve method was utilized for the quantitation. The results indicated that 82 pesticides showed good linear relationship within the corresponding concentration ranges (r≥0.99). The detection limits (LOD) were 0.3-5 μg/kg and the limits of quantitation (LOQ) were 1-20 μg/kg. Under spiked levels of 0.02, 0.05 and 0.1 mg/kg, the average recoveries of most pesticides were between 70%-111%, and the relative standard deviations (RSD, n = 6) were less than 19%. This method is simple, accurate and efficient, which can meet the requirements for the detection of 82 pesticide residues in V. yedoensis samples.