超高效液相色谱-四极杆-飞行时间质谱法快速筛查茶叶中的204种农药残留

摘要

An analytical method was established for the simultaneous determination of 204 pes-ticide residues in tea by ultra performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry( UPLC-Q-TOF/MS). The samples were extracted with acetonitrile, and cleaned-up by solid phase extraction( SPE)with a Carb-PSA cartridge,eluted with aceto-nitrile-toluene(3:1,v/v),determined by UPLC-Q-TOF/MS and quantified by external standard method. A data base of the accurate mass numbers and a library which contains the 204 pesti-cides were established. The automatic retrieval of detection results was carried on according to the characteristics of the compound,such as accurate mass,retention time,isotopic ratio,and so on. Based on the above results,the qualitative identifications of the 204 pesticides were accomplished without the contrast of standard substances. The results indicated that this meth-od can be used to determine the 204 pesticides in tea. At the three spiked levels of 10,20,50μg/kg,mean recoveries for the 204 pesticides in tea were between 68. 1% and 117. 2%,with the relative standard deviations( RSDs)ranging from 3. 1% to 18. 9%. The limits of quantifica-tion for the 204 pesticides were lower than 10 μg/kg. The method has been applied to four posi-tive samples,and the results generally accord with the detection results by the method of GB/T 23205-2008. This method has the characteristics of high efficiency,as well as high sensitivity and accuracy,which can meet the requirement of the determination of the 204 pesticides in tea.%利用超高效液相色谱-四极杆-飞行时间质谱（ UPLC-Q-TOF／MS）技术建立了茶叶中204种农药残留的快速筛查和确证检测方法。样品采用乙腈提取，经 Carb-PSA 固相萃取小柱净化，用乙腈-甲苯（3：1，v／v）洗脱，采用UPLC-Q-TOF／MS检测，外标法定量。建立了204种农药的一级精确质量数据库和二级谱图库，通过化合物的精确质量数、保留时间、同位素比值等信息对检测结果进行自动检索，从而在无对照标准品的情况下完成了204种农药的定性鉴定。结果表明，该方法可以同时对茶叶中204种农药残留进行快速筛查，在10、20、50μg／kg 3个添加水平下的平均回收率为68.1％~117.2％，相对标准偏差为3.1％~18.9％。定量限均小于10μg／kg。采用本方法对4份阳性样品进行检测，所得结果与 GB／T 23205-2008的检测结果基本一致。该方法快速、灵敏、准确，可用于茶叶中204种农药残留的快速筛查。