离子交换色谱法测定西番莲中有机酸

Determination of organic acids in passiflora by ion exchange chromatography

建立同时测定西番莲中苹果酸、琥珀酸和柠檬酸的离子交换色谱分析方法。样品用8%的乙醇水溶液提取,经涡旋和离心后通过0.45μm滤膜和On-guard II RP固相萃取小柱去除杂质,采用AS19阴离子交换色谱柱分离,以在线产生的KOH淋洗液梯度洗脱,用电导检测器测定。在优化的色谱条件下检测,苹果酸、琥珀酸、柠檬酸的线性范围分别为1～10,1～10,5～50 mg/L,线性相关系数均在0.999以上,检出限分别为0.005,0.005,0.010 mg/L。样品加标回收率为82%～96%,测定结果的相对标准偏差为2.62%～3.66%(n=6)。该方法样品前处理简单,重复性好,可用于西番莲样品中有机酸的测定。

An ion exchange chromatographic method was developed to determine the malic acid,succinic acid and citric acid in Passiflora.Ethanol aqueous solution(volume ratio was 8%)was used as the extraction agent,and samples of Passiflora were whirlpool mixed and centrifuged.Then the solution was filtered with 0.45μm filtering membrane and on-guard II RP solid phase extraction column so as to remove the impurities.The filtrate was separated by AS19 anion chromatographic column,and determined by electrical conductivity detector after being gradient eluted with aqueous potassium hydroxide generated online.The results showed that the linear ranges of malic acid,succinic acid and citric acid were 1–10,1–10,5–50 mg/L,respectively,under optimized chromatographic conditions.The correlation coefficients of calibration curves were more than 0.999,and the detection limits of malic acid,succinic acid and citric acid were 0.005,0.005 and 0.010 mg/L,respectively.The recoveries of standard addition ranged from 82%to 96%,and the relative standard deviations of determination results were 2.62%–3.66%(n=6).This method has the advantages of simple operation,good repeatability,which can meet the determination requirements of organic acids in Passiflora.