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    固相萃取柱净化-气相色谱-三重四极杆质谱法测定茶叶中角鲨烯的含量

    Determination of Squalene in Tea by Gas Chromatography-Triple Quadrupole Mass Spectrometry after Purification with Solid Phase Extraction Column

    • 摘要: 在5.000 g茶叶样品中加入100 mg·L-1角鲨烷内标溶液50 μL和石油醚50 mL,涡旋3 min,超声30 min,离心3 min,上清液过定性滤纸,滤液置于100 mL鸡心瓶中,重复提取1次,合并提取液,于40℃旋转浓缩至1~2 mL。在上述溶液中加入体积比3∶1的乙腈-甲苯混合溶液3 mL,过活化好的石墨化碳黑-氨基复合(Cleanert GCB-NH2)小柱,用6 mL体积比3∶1的乙腈-甲苯混合溶液分两次清洗鸡心瓶,洗液全部过柱,再用体积比3∶1的乙腈-甲苯混合溶液25 mL洗脱小柱。收集洗脱液,于40℃旋至近干,氮气吹干,加入5.00 mL正己烷,超声30 s,过0.22 μm有机滤膜,滤液在气相色谱仪的HP-5MS色谱柱上进行程序升温分离,所得目标物在三重四极杆质谱仪的多反应监测模式下检测,内标法定量。结果显示,角鲨烯标准曲线的线性范围为0.030 0~2.00 mg·L-1,检出限(3S/N)为0.010 0 mg·kg-1;加标回收率为77.6%~95.6%,测定值的相对标准偏差(n=6)为4.5%~8.3%。方法用于48批不同产地经不同发酵工艺制备的茶叶样品的分析,均检出了角鲨烯,检出量为0.10~29.5 mg·kg-1

       

      Abstract: An aliquot (50 μL) of 100 mg·L-1 squalane internal standard solution together with 50 mL of petroleum ether was mixed with 5.000 g of the tea sample, and the mixture was vortexed for 3 min, ultrasonicated for 30 min, and centrifuged for 3 min. The supernatant was passed through qualitative filter paper, and the filtrate was placed into a 100 mL-chicken heart bottle. The above extraction process was repeated once, and the extract was combined, and rorated and concentrated to 1-2 mL at 40℃. After 3 mL of acetonitrile-toluene mixed solution at volume ratio of 3:1 was added into the above solution, and the solution obtained was passed through the Cleanert GCB-NH2 cartridge activated beforehand. The chicken heart bottle was washed twice with 6 mL of acetonitrile-toluene mixed solution at volume ratio of 3:1, and the washing was passed through the cartridge. Acetonitrile-toluene mixed solution at volume ratio of 3:1 of 25 mL was taken and used for eluting the cartridge. The eluent was collected, rorated and concentrated to near dryness at 40℃, blown to dry by nitrogen, mixed with 5.00 mL of n-hexane, ultrasonicated for 30 s, and passed through 0.22 μm organic filter membrane. The filtrate was separated by temperature-programmed on the HP-5MS column in the gas chromatograph. The target obtained was detected by multiple reaction monitoring mode of triple quadrupole mass spectrometer, and quantified by internal standard method. As found by the results that the linear range of squalene was in the range of 0.030 0-2.00 mg·L-1, with detection limit (3S/N) of 0.010 0 mg ·kg-1. The results of recovery obtained by standard addition method were in the range of 77.6%-95.6%, giving RSDs (n=6) of the determined values in the range of 4.5%-8.3%. The proposed method was applied to the analysis of the 48 batches of tea samples prepared by different fermentation processes from different producing regions, with the detected amounts in the range of 0.10-29.5 mg·kg-1.

       

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