白茶黄酮醇类物质的HPLC测定及水解工艺优化

HPLC determination and hydrolysis process optimization of flavonol substances of white tea

以研究白茶浸提液中杨梅素、槲皮素和山奈酚3种黄酮醇类物质的高效液相色谱(HPLC)检测方法及优化水解工艺为目的,通过精密度和加标回收率的测定,在确定HPLC检测方法可靠性的基础上,进一步采用正交试验法优化样品制备中的水解条件.结果表明,制定的HPLC分离条件能有效分离芦丁、杨梅素、槲皮素和山奈酚,所得的标准曲线方程在线性范围内具有较高的精密度和加标回收率.白茶中3种黄酮醇类物质的最优水解工艺条件为:在5 m L白茶浸提液中添加5m L 3 mol·L-1盐酸,于80℃水浴锅中水解30 min.最优水解工艺的精密度均较高,在水解过程中山奈酚最稳定,杨梅素容易被分解,芦丁的水解转化率为94.32%.可见,将试验所得的HPLC检测方法及最优水解工艺用于测定白茶中黄酮醇类物质的含量是可行的,且可使白茶提取液中黄酮醇苷总量的水解趋于最大化.

To study test method of high performance liquid chromatography （HPLC） and optimal hydrolysis process of the three kinds of flavonols content which included arbutus pigment,quercetin and kaempferol in white tea extracts,through the measurement of precision and recovery,and the reliable HPLC method,the hydrolysis conditions of samples in preparation were optimized by using orthogonal experimental design.The results showed that rutin,arbutus pigment,quercetin and kaempferol could be effectively separated under the HPLC separation conditions,and higher precision and standard addition recovery rate were gained within their obtained linear scope of the standard curve equation.The optimal hydrolysis conditions for the flavonol substances of white tea was as follows：5 mL 3 mol · L^-1 HCl was added to the 5 mL white tea extract,then hydrolysised 30 min in 80℃ water bath pot.It also showed that the precision of the optimal hydrolysis method was relatively high; the kaempferol in hydrolysis process was stablest,while arbutus pigment was easy to be resolved; the hydrolysis conversion of rutin was 94.32%.It was concluded that the HPLC detection method and the optimal hydrolysis method were avaible to determine the flavonol substances content of white tea,which could make the hydrolysis of the total flavonol glycosides in white tea extracts tend to be maximized.