茶树中总有机酸的自动电位滴定仪测定方法

A Method for Determination of Total Organic Acids in Tea Plant with Automatic Potentiometic Titration

建立了-种应用自动电位滴定仪快速检测茶树中总有机酸的方法,并用该方法测定了茶树新芽、幼叶、成熟叶,以及凋落叶中总有机酸的含量.结果表明,样品经乙醇提取、减压浓缩,再经过先碱化后酸化处理,乙酸乙酯萃取后,用自动电位滴定仪检测茶树叶片中的总有机酸,有机酸的添加量为2.0-45.0 mg·g^-1,回收率为96.0%-99.6%,相对标准偏差（RSD）≤5.7%,该方法是茶树叶片总有机酸含量测定的简单快捷方法.运用该方法,新芽、幼叶、成熟叶、凋落叶总有机酸含量的测定值分别为44.9、20.1、21.1、1.99 mg·g^-1.

A method for determination of total organic acids in tea plant by automatic potentiometic titrator wasestablished in this study. And the content of total organic acids in bud, young leaf, mature leaf and withered leaf weredetermined by this method. The results showed that after extracting by ethanol, concentrated under reduced pressure,the concentrated solution was alkalized and acidified, then detected with automatic potentiometic titrator, thesamples were spiked at the level of 2.0-45.0 mg·g^-1, and the recovery of organic acids range from 96.0%-99.6% withRSD less than 5.7%. This simple and sensitive method meets with the analytical requirement to total organic acids intea. The content of total organic acids in bud, young leaf, mature l eaf and withered leaf was 44.9, 20.1, 21.1 and1.99 mg·g^-1 respectively.