基于UPLC-MS/MS同时分析福建乌龙茶和白茶中的儿茶素类物质
Simultaneous Analysis of Catechins in Several Fujian Oolong Tea and White Tea Products by UPLC-MS/MS
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摘要: 目的:建立超高效液相色谱-串联质谱法(UPLC-MS/MS)快速分析茶叶中儿茶素类物质如儿茶素(Catechin,C)、表儿茶素(Epicatechin,EC)、没食子儿茶素(Gallocatechin,GC)、表没食子儿茶素(Epigallocatechin,EGC)、表没食子儿茶素没食子酸酯(Epigallocatechin gallate,EGCG)等,对几种福建乌龙茶和白茶中的儿茶素类物质进行分析。方法:实验使用Waters T3 C18色谱柱(250 mm×4.6 mm,5 μm),以0.1%(V/V)甲酸水溶液和甲醇为流动相对目标物进行梯度洗脱后,电喷雾正离子扫描方式下多反应监测(MRM)模式分析。结果:8 min内即可完成茶叶中8种儿茶素类物质的上机检测;儿茶素类物质的检出限为0.2~1.1 μg/L,线性方程的相关系数(r)为0.9966~0.9994。用建立的方法分析所采集的几种福建茶叶样品,表没食子儿茶素没食子酸酯(EGCG)相对于其它儿茶素类物质在茶叶中的含量最高,约占茶叶中儿茶素总量的60%。乌龙茶中儿茶素总量的含量范围为43.59~45.21 mg/g,白茶儿茶素总量的含量范围为50.52~70.71 mg/g。结论:建立的方法灵敏、准确、快速,研究结果可为福建茶叶产品的开发提供一定的科学依据。Abstract: Objective:A rapid ultrahigh performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry(UPLC-MS/MS)method was established for the simultaneous determinationof eight catechin compounds including catechin(C),epicatechin(EC),gallocatechin(GC),epigallocatechin(EGC),epigallocatechin gallate(EGCG)in several Fujian tea products(oolong tea and white tea).Method:The compounds were separated on a waters T3 C18 column with 0.1%(V/V)formic acid aqueous solution and methanol as mobile phase by gradient elution,then analyzed by positive electrospray ionization tandem mass spectrometry under multiple reaction monitoring(MRM)mode. Results:8 catechin compounds could be detected in 8 wmiutes,the limits of detection(LOD)were in the range of 0.2~1.1 μg/L and there was a good linearity over tested concentration ranges with the correlation coefficients(r)from 0.9966 to 0.9994.The content of epigallocatechin gallate(EGCG)was much higher than other catechin compounds in all the testing samples,which could up to 60% of the total catechins. The results showed that the content of total catechins was 43.59~45.21 mg/g in oolong tea,and from 50.52 to 70.71 mg/g in white tea. Conclusion:The method employed to detect 8 catechin compounds was sensitive,quick and accurate,and the study could provide scientific evidences for the utilization of Fujian tea products.