离子色谱法检测食品添加剂焦碳酸二甲酯中的氯离子

建立离子色谱法检测食品添加剂焦碳酸二甲酯（DMDC）中的杂质氯离子的方法。样品用水溶解超声定容后，采用SH-AC-1阴离子交换柱（250mm×4．6mm，5μm）分离，抑制电导法检测。考察了淋洗液种类、浓度对氯离子与干扰离子分离度的影响。最佳色谱条件：以0．005mol／L的四硼酸钠水溶液为淋洗液，流速1．0mL／min。在此条件下，样品中的氯离子可以和其它干扰离子分离，而且分离度达3．0以上，峰形对称。在氯离子浓度为0．1～5．0mg／L的范围内，可获得良好的线性关系，线性相关系数大于0．999；氯离子检出限（S／N=3）达0．007mg／L，加标回收率为97．5％～98．9％。该方法可以用于食品添加剂DMDC中氯离子的测定。

Determination of Chloride Ion in Dimethyl Dicarbonate as Food Additives by Ion Chromatography

A method was established for the determination of chloride ion in DMDC （ dimethyl dicarbonate ） as food additives by ion exchange chromatography. Sample was separated on SH-AC-1 （ 250 mm × 4.6 mm, 5 μm ） anion exchange column with suppressed conductivity after being dissluted by water. The effects of the types of eluent, concentration on separation of chloride ion and interfering ion were investigated. The optimized chromatographic conditions were as follows ： 0.005 mol/L of sodium borate solution as eluent with flow rate of 1.0 mL/min. On these conditions, the chloride ions and other interfering ions in the sample could be completely separated. The resolution of peak attained 3.0 and the symmetry of peaks was better. The good linear calibration curve were obtained in the chloride ion concentration range of 0.1-5.0 mg/L with the linear relative coefficient more than 0.999. Chloride ion detection limit （S/N=3） was 0.007 mg/L, and the standard added recovery was 97.5%-98.9%. The method is suitable for determination of chloride ions in DMDC as food additives.