建立UPLC -MS/MS法测定遵义茶样8种儿茶素含量

Determination of 8 Catechins in Zunyi Tea Samples Using UPLC-MS/MS

建立一种利用超高效液相色谱-串联质谱(UPLC-MS/MS)来检测茶叶中8种儿茶素C、EC、ECG、EGC、EGCG、GA、GCG和CAF的方法:样品采用70%甲醇水作为提取溶剂在70℃水浴中提取两次后,经ACQUITY UPLC HSS T3色谱柱(100mm×2.1mm,1.8μm)分离,以水-乙腈溶液作为流动相来进行梯度洗脱,流速为0.3mL/min,柱温40℃,采用AJS-ESI源正负模式同时扫描,多反应监测(MRM)定量。8种儿茶素在优化的色谱质谱条件下,分离度良好,其中ECG、C、EC在浓度1.25μg/mL~20μg/mL;EGCG和ECG在浓度0.5μg/mL~8μg/mL的以及KFY、GCG和GA在1.5μg/mL~24μg/mL的系列标准使用液范围内线性关系良好。加标回收率为70.9%~98.2%;检出限为0.08~0.20 ng/g;相对标准偏差(RSD)为2.2%~5.2%。目前对红茶实物标样等级的研究大多关注在感官上,鲜有对各等级茶叶中儿茶素类成分进行系统的研究。因此,本研究对首次利用UPLC-MS/MS对遵义市“两绿一红”茶叶实物标准样中8种儿茶素含量进行检测,并比较不同等级遵义红茶的儿茶素含量,结合感官评审,为茶叶样品的定级提供基础数据。

To detect eight catechins(gallocatechin,catechin gallate,catechin,epicatechin,epigallocatechin gallate,gallocatechin gallate,epicatechin gallate,catechin gallate)in tea by ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).Methods:The samples were extracted with 70%methanol water in a 70℃water bath and filtered twice.The separation was performed on an ACQUITY UPLC HSS T3(100mm×2.1 mm,1.8μm)column with gradient elution using a mobile phase of waters-acetonitrile at 0.3mL/min.Column temperature was set as 40℃,AJS-ESI source(positive and negative)mode was used for simultaneous scanning and multiple response monitoring(MRM)was used for quantification.Results:The separation of the eight compounds was seperated well under the optimized chromatography-mass spectrometry conditions.The linear relationship was good in the concentration rang of 1.25μg/mL~20μg/mL(ECG;C;EC);0.5μg/mL~8μg/mL(EGCG;ECG)and 1.5μg/mL~24μg/mL(KFY;GCG;GA),standard samples of guizhou tea(Meitan Cuiya,Fenggang Zinc-selenium green tea,zunyi black tea)was spiked at(high,medium,low)levels.The average recoveries were 70.9%~98.2%.The detection limits of 0.08~0.20 ng/g.RSD ranged from 2.2%to 5.2%.At present,most of the studies on the standard grades of black tea are focused on the senses,and there are few systematic studies on the catechins in different grades of tea.Therefore,this study used UPLC-MS/MS for the first time to detect the content of 8 catechins in the physical standard samples of"Two green and one red"tea in Zunyi city,and compared the content of catechins in different grades of Zunyi black tea,combined with sensory evaluation to provide basic data for the grading of tea samples.