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（ r2﹥0.99），相对标准偏差分别小于8.6％和9.1％，定量限分别为0.3~6.9μg／kg 和10.2~44.9μg／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。
A method was developed for the analysis of 24 pesticide residues in tobacco based on gas chromatography-time of flight mass spectrometry( GC-TOF MS)under negative chemi-cal ionization( NCI)and electron impact ionization( EI)modes coupled with microwave-assis-ted extraction. The tobacco samples were extracted with 10 mL dichloromethane-n-hexane (3∶1,v/v)for 10 min at 100 ℃ by microwave-assisted extraction,and cleaned up by a florisil solid phase extraction cartridge,then detected by GC-TOF MS. For GC-NCI-TOF MS and GC-EI-TOF MS,the linear correlation coefficients(r2)were both better than 0. 99,the relative standard deviations( RSD)were less than 8. 6% and 9. 1%,the limits of quantification ranged from 0. 3 μg/kg to 6. 9 μg/kg and 10. 2 μg/kg to 44. 9 μg/kg,and the recoveries ranged from 75. 2% to 94. 8% and 75. 0% to 95. 1% at three spiked levels,respectively. Comparison of the total ion chromatograms and mass spectra under NCI and EI modes,the NCI modes have the advantages of higher selectivity with better matrix interference resistance and simpler spectrogram. The detection limits in NCI mode were lower by more than one order of magni-tude than those in EI mode,GC-NCI-TOF MS method was superior in analyzing low level of pesticide residues and complex matrix.
参考文献
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%