离子色谱法测定茶叶中多种有机酸和无机阴离子的研究

Determination of multiple organic acids and inorganic anions in tea by ion chromatography

采用离子色谱分析方法同时测定了茶叶中奎尼酸、乳酸、乙酸、丙酮酸、酒石酸、草酸、富马酸、柠檬酸、水杨酸和F-、Cl^(-)、Br^(-)、NO_(2)^(-)、NO_(3)^(-)、SO_(4)^(2-)、PO_(4)^(3-)的含量。茶样经沸水浴浸提30 min后,采用Dionex IonPac TM AS11-HC分析柱和Dionex IonPac TM AG11-HC保护柱,柱温为30℃,采用KOH淋洗液梯度洗脱,流速为0.85 mL·min^(-1),抑制电流为116 mA,电导检测器检测,池温为35℃。离子色谱分析方法学考察结果表明,各有机酸和无机阴离子的线性相关系数均达到0.999以上,该方法的精密度、重复性、准确性良好,茶样提取液在24 h内稳定。结果表明,所测茶样中含量较高的有机酸主要有奎尼酸、草酸、酒石酸,含量较高的无机阴离子主要有PO43-、SO_(4)2-、Cl-,该研究可促进对茶叶产品的质量控制,为茶叶中有机酸组分检测方法标准和无机阴离子限量标准的制定提供参考。

A simultaneous determination method for various organic acids(quinic acid,lactic acid,acetic acid,pyruvic acid,tartaric acid,oxalic acid,fumaric acid,citric acid,salicylic acid)and inorganic anions(F^(-),Cl^(-),Br-,NO_(2)^(-),NO_(3)^(-),SO_(4)^(2-),PO_(4)^(3-))in tea products was developed using ion chromatography.After 30 minutes of extraction in a boiling water bath,the tea samples were analyzed using a Dionex IonPac AS11-HC analytical column and a Dionex IonPac AG11-HC guard column,with a column temperature of 30℃,eluted with a gradient of KOH eluent,the elution flow rate was 0.85 mL/min,and the suppression current was set to 116 mA.Detection was achieved using a conductivity detector with a pool temperature of 35℃.The results of the ion chromatographic method investigation showed that the linear correlation coefficients for each organic acid and inorganic anion were all above 0.999.Additionally,the method demonstrated good precision,repeatability,and accuracy,with tea sample extracts remaining stable for up to 24 hours.The results showed that quinic acid,oxalic acid,and tartaric acid were the predominant organic acids,while PO_(4)^(3-)、SO_(4)^(2-)and Cl^(-)were the predominant inorganic anions.This study can contribute to the quality control of tea products and provide references for the establishment of detection method standards for organic acid components and limit standards for inorganic anions in tea.