热解吸低温等离子体质谱技术直接快速筛查蔬菜中的有机磷农药

在传统低温等离子体质谱技术的基础上引入热解吸装置,建立了一种直接快速筛查蔬菜中有机磷农药的新方法。白菜样品经乙腈提取,离心取上清液进行质谱检测,在正离子检测模式下,将承载样品的载玻片置于加热块上进行解吸,被低温等离子体射流离子化后进入质谱检测。结果表明,在优化实验条件下,8种有机磷农药在0.005～0.200 mg/L质量浓度范围内线性良好,相关系数均大于0.99,检出限为0.001～0.010 mg/L,加标回收率为90.5%～119%,相对标准偏差(RSD,n=6)为12%～17%。与无热解吸条件相比,检测灵敏度提高了9.3～41.7倍。该方法操作简单,无复杂的样品前处理,灵敏度高、准确性好,可用于蔬菜中8种有机磷农药残留的同时测定,在大批量样品的非靶向分析中有较大的应用前景。

Rapid Screening of Organophosphorus Pesticides in Vegetables by Low Temperature Plasma Mass Spectrometry with Thermol Desorption

A low temperature plasma ionization mass spectrometry with a thermal desorption device was developed for the direct and rapid screening of 8 organophosphorus pesticides in vegetables.The vegetable sample was extracted with acetonitrile,and the supernatant was analyzed by mass spectrometry after centrifugation.In the positive ion detection mode,the sample was placed on a heating block for desorption,ionized with a low temperature plasma,and then subjected to mass spectrometry.Results showed that there were good linear relationships for the 8 analytes in range of 0.005-0.200 mg/L with their correlation coefficients greater than 0.99.The detection limits were in the range of 0.001-0.010 mg/L.The recoveries for Chinese cabbage ranged from 90.5% to 119% with relative standard deviations(RSDs,n=6) of 12%-17%.The detection sensitivity was improved by 9.3 to 41.7 times compared with that without thermal desorption.With simple operation,easy pretreatment,high sensitivity and good accuracy,the method could be applied in the simultaneous determination of pesticide residues in vegetables,and has a great application prospect in non targeted analysis for large batch of samples.