Kotani Akira, Miyaguchi Yuji, Tomita Eiji, Takamura Kiyoko, Kusu Fumiyo
Department of Analytical Chemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
J Agric Food Chem. 2004 Mar 24;52(6):1440-4. doi: 10.1021/jf0306486.
Voltammetric determination of acids by means of the electrochemical reduction of quinone was applied to high-performance liquid chromatography (HPLC) with electrochemical detection (ED) for determining organic acids in fruit wines. A two-channel HPLC-ED system was fabricated by use of an ion-exclusion column and an electrochemical detector with a glassy carbon working electrode. Aqueous solution of 0.1 mM HClO(4) and ethanol containing 2-methyl-1,4-naphthoquinone served as a mobile phase and reagent solution, respectively. Determination of acetic, citric, lactic, malic, succinic, and tartaric acids was made by measuring the peak areas of the flow signals due to the reduction current of quinone caused by the eluted acids. The peak area was found to be linearly related to the acid amount ranging from 0.1 to 40 nmol per 20 microL injection. The present method was characterized by reproducibility with the simple and rapid procedure without derivatization of analytes. The method was shown as an effective means for following acid contents in fruit juices during fermentation with wine yeast.
通过醌的电化学还原伏安法测定酸被应用于配有电化学检测（ED）的高效液相色谱（HPLC），以测定果酒中的有机酸。利用离子排斥柱和带有玻碳工作电极的电化学检测器构建了一个双通道HPLC-ED系统。0.1 mM高氯酸（HClO₄）水溶液和含有2-甲基-1,4-萘醌的乙醇分别用作流动相和试剂溶液。通过测量洗脱酸引起的醌还原电流所产生的流动信号的峰面积来测定乙酸、柠檬酸、乳酸、苹果酸、琥珀酸和酒石酸。发现峰面积与每20微升进样中0.1至40纳摩尔的酸量呈线性关系。本方法的特点是具有重现性，程序简单快速，无需对分析物进行衍生化。该方法被证明是跟踪葡萄酒酵母发酵过程中果汁中酸含量的有效手段。
