Liu Chunbo

微波辅助萃取-气相色谱-负化学电离/电子轰击电离-飞行时间质谱法测定烟草中农药残留

建立了微波辅助萃取结合气相色谱-飞行时间质谱(GC-TOF MS)技术在负化学电离(NCI)源和电子轰击电离(EI)源两种模式下测定烟草中24种农药残留的分析方法。烟叶样品于100℃下用二氯甲烷-正己烷(3:1, v/v)混合溶剂微波萃取10 min,萃取液经弗罗里硅土固相萃取柱净化后进行检测分析。在NCI源和EI源质谱模式下,24种农药的线性关系均良好( r 2 >0.99),相对标准偏差分别小于8.6%和9.1%,定量限分别为0.3~6.9 μg/kg和10.2~44.9 μg/kg,加标回收率分别为75.2%~94.8%和75.0%~95.1%。比较两种离子源模式下的色谱图和质谱图,NCI源模式较EI源模式的选择性好、灵敏度高、基质干扰小、图谱简单易于解析,检出限低一个数量级以上,在分析低含量、复杂基质的样品时更具优势。

Fast Determination of Free Solanesol in Tobacco with UPLC-UV Spectrophotometer

In order to simplify the pretreatment procedures,tobacco sample was directly extracted by methanol and the UPLC-UV conditions were optimized,then the solanesol content in the obtained extract was determined.The results showed that: 1) The optimal conditions of extraction were: methanol as solvent and extracting for 20 minutes at 25 ℃.2) The concentration of working curve of this method ranged from 10 to 200 mg/L.Good linear relationship existed between mass concentrations and peak areas with the correlation coefficient of 0.9997;3) The detection limit of this method was 0.054 mg/L with the relative standard deviation of 2.1% and the average recoveries of 105.5%.This method is fast,simple,accurate and suitable for the determination of solanesol content in tobacco.