IC法测定食品添加剂EDTA二钠中氨三乙酸

Determination of nitrilotriacetic acid in food additive disodium ethylenediaminetetraacetate by ion chromatography

乙二胺四乙酸二钠是食品工业中一种重要的添加剂。本文建立离子色谱（IC）测定食品添加剂乙二胺四乙酸二钠中氨基三乙酸的方法。乙二胺四乙酸二钠样品用100 g/L的KOH溶液溶解,取6个样品溶液加入系列氨三乙酸标准,用水定容至500m L。上述定溶液以KOH溶液为流动相,采用Ion Pac AS11—HC柱（250mm×4 mm）将分离后,导入电导检测器检测,采用基质配制曲线,外标法定量。实验中优化了前处理条件、色谱条件和计算方法的最佳条件。在优化实验条件下,氨三乙酸的线性范围0.1~10mg·L-1,相关系数为0.999,方法检出限为0.005%,回收率为97%~104%,方法精密度为5.4%。该方法简单、灵敏、操作成本低,较现有的极谱法测定准确度高,应用该方法分析了食品添加剂乙二胺四乙酸二钠样品,结果令人满意。

Ethylenediaminetetraacetate was widely used in food industry as an important food additive. An analysis method was established for determination of nitrilotriacetic acid in disodium ethylenediaminetetraacetate as food additive by ion chromatography （IC） . The sample was dissolved by 100 g/L KOH solution. A series of nitrilotriacetic acid standards were added into sample solution, with constant volume to 500mL by water. These sample solutions were separated by IonPac AS11-HC column （250mm × 4 mm） in IC, with conductivity detector and KOH as mobile phase. Measurement results were quantified using the matrix curve. The pretreatment methods of the samples, chromatographic separation conditions and quantitative methods were optimized in the experiment. Under the optimized conditions, it was showed that nitrilotriacetic acid was separated well in the linear range of 0.1 - 10mg. L 1, and correlation coefficient was 0.999, detection limit of the method was 0.005%, recoveries of nitrilotriacetic acid was between 97% and 104% with relative standard deviations of method less than 5.4%. The proposed method was more accurate than polarography, and has been successfully applied to determine nitrilotriacetic acid in ethylenediaminetetraacetate as food additive with easy operation, high sensitivity and low cost.