亲水性C18硅胶反相色谱柱同时分离测定红茶中的有机酸

Simultaneous separation and determination of organic acids in black tea by high performance liquid chromatography using polar-enhanced C18 column

中文关键词:  亲水性C18硅胶反相色谱柱  有机酸  红茶

英文关键词:polar-echanced C18 column  organic acids  black tea

中文摘要:

      目的 使用亲水性C18硅胶反相色谱柱同时分离测定红茶中11种有机酸。方法 经ACCHROM XAqua C18 柱(4.6 mm×150 mm, 5 μm)分离, 以0.1%三氟乙酸-乙腈为流动相梯度洗脱, 流速1.0 mL/min, 柱温25 ℃, 检测波长214 nm。结果 11种有机酸在13 min内实现基线分离, 平均回收率为92.07%~101.64%, 相对标准偏差为0.54%~1.93%, 各有机酸线性相关系数r >0.9986。对不同产地6个红茶样品进行测定, 云南凤庆红茶样品有机酸含量最高(668.62 mg/L), 锡兰红茶样品含量最低(386.67 mg/L); 红茶有机酸以草酸为主, 含量范围在119.67~193.18 mg/L; 乳酸(0~193.43 mg/L)和乙酸(36.62~193.98 mg/L)含量在不同产地红茶样品中相对差异较大。结论 本实验建立了一种较准确、高效、简便的茶叶有机酸检测技术与方法, 运用此方法测定不同产地红茶有机酸含量并分析与比较不同红茶的有机酸组分差异性, 并为红茶品质风味的审评及加工工艺改良提供一定数据参考。

英文摘要:

      Objective To establish a method for the simultaneous separation and determination of 11 kinds of organic acids in black tea by reversed-phase high performance liquid chromatography on a polar-enhanced C18 column. Methods Separation was achieved using an ACCHROM XAqua C18 column (4.6 mm×150 mm, 5 μm), under the gradient elution with the mobile phase of acetonitrile and 0.1% ( v:v ) formic acid/water, 1.0 mL/min, 25 ℃ and detection at 214 nm. Results The separation was easily completed in 13 min and the recoveries of 11 kinds of organic acids were from 92.07% to 101.64%, with the relative standard deviation between 0.54%~1.93%, and the coefficients of correlation were not less than 0.9986. Six black tea samples from different districts were determined, the organic acids contents of the sample from Fengqing, Yunnan was the highest (668.62 mg/L), while Ceylon tea sample was the lowest (386.67 mg/L); the oxalic acid occupied the highest ratio in black tea organic acids and varied from 119.67~193.18 mg/L in 6 samples, and the contents fluctuation of lactic acid and acetic acid were relatively larger in 6 samples as 0~193.43 mg/L and 36.62~193.98 mg/L, respectively. Conclusion This experiment has established a relatively accurate, efficient, convenient detection technology and method of organic acids in tea, using the method to detect organic acid contents in black tea from different regions. It provided some reference data for sensory evaluation of black tea quality and flavor and improving the processing technology by analyzing and comparing the differences of organic acid group in different black tea.