离子色谱法测定饮料中的柠檬酸盐

Determination of Citrate in Beverage by SPE-ion Chromatography

研究了固相萃取-离子色谱法测定饮料中柠檬酸盐含量。将样品稀释后以4mL/min的流速通过DI- ONEX OnGuardⅡRP固相萃取柱去除脂肪等疏水性化合物后,经0.2μm滤膜过滤,直接进样测定。用35mM的KOH溶液等度淋洗,流速为1.0mL/min,采用AS11-HC型阴离子色谱柱进行分析。在此检测条件下,柠檬酸盐有很好的线性(r^2=0.9998)。该方法的最小检出限为0.036μg/mL,回收率为96%～102%,精密度<1.5%。实验结果表明,该方法简便、快速,且检测结果准确。

The method for determination of citrate in beverage by the SPE （ Solid Phase Extraction ） - 1on chromatography was researched on the basis of experiment. The sample was diluted and passed through the DIONEX OnGuard Ⅱ RP sample pretreatment cartridge at a flow rate of 4mL/min to wipe off fat and other hydrophobic compound, then was filtered by 0.2μm filters and was determined directly. The separation was performed with 35mM KOH as isocratic mobile phase at a flow rate of 1.0mL/min and accomplished with a Dionex Ion Pac ASll - HC column. The calibration curve of citrate was linear. And the correlation coefficient was 0. 9998. Limit of detection for the method was 0. 036μg/mL . The recoveries were 96% - 102%. The precision was less than 1. 5%. The method was simple, rapid and accurate.