基于HPLC法同时测定牛心柿汁中5种有机酸含量

Simultaneous determination of 5 organic acids content in Niuxin persimmon juice by HPLC

建立了高效液相色谱法(HPLC)同时测定牛心柿汁中5种有机酸含量的方法,并比较不同浓缩方式(真空、常压)柿汁中有机酸含量。结果表明,优化后的色谱条件为:紫外检测器检测波长210 nm,流动相为甲醇∶0.01 mol/L磷酸二氢钾溶液(pH2.7)=1∶99(V/V),流速0.6 mL/min,柱温25℃。在此优化条件下,5种有机酸均能有效分离,线性范围较宽,相关系数R^(2)>0.9990,检出限为3.03~26.39μg/mL,定量限为10.0~87.95μg/mL,加标回收率为90.13%~97.62%,精密度试验结果相对标准偏差(RSD)均<5%,表明该检测方法精密度及准确度良好。HPLC结果表明,不同浓缩柿汁5种有机酸含量均低于原汁,真空浓缩优于常压浓缩,有机酸含量高且差异显著(P<0.05)。有机酸含量变化分别为苹果酸0.129~0.151 mg/mL、奎尼酸0.152~0.209 mg/mL、乳酸0.030~0.068 mg/mL、乙酸0.239~0.533 mg/mL、柠檬酸0.297~0.326 mg/mL。

The HPLC method for simultaneous determination of 5 kinds of organic acids was established,and the contents of organic acids in Niuxin persimmon juice with different concentration methods(vacuum,atmospheric pressure)were compared.The results showed that the optimal chromatographic conditions were as follows:UV detection wavelength 210 nm,methanol and 0.01 mol/L KH_(2)PO_(4)(pH=2.7)(1∶99,V/V)as mobile phase,flow rate 0.6 ml/min,and column temperature 25℃.The 5 kinds of organic acids were successfully separated under the optimal conditions,and the method displayed a wide linear range with correlation coefficients R^(2)>0.9990.The limits of detection were in the range of 3.03-26.39μg/ml,the limits of quantitation were in the range of 10.0-87.95μg/ml,the spiked recoveries ranged from 90.13%to 97.62%,and the relative standard deviation(RSD)of the precision tests result was all<5%,indicating that the precision and accuracy of the method were good.The HPLC results showed that the contents of 5 kinds of organic acids in different concentration persimmon juice were lower than those in original persimmon juice,and the vacuum concentration was better than atmospheric concentration,with higher organic acids content and significant difference(P<0.05).The contents of organic acids were malic acid 0.129-0.151 mg/ml,quinic acid 0.152-0.209 mg/ml,lactic acid 0.030-0.068 mg/ml,acetic acid 0.239-0.533 mg/ml,citric acid 0.297-0.326 mg/ml,respectively.