离子色谱法测定七水合硫酸钴中氯

Determination of chlorine in cobalt sulfate heptahydrate by ion chromatography

建立了一种化学试剂七水合硫酸钴中氯含量的测定方法.以高纯水溶解样品,通过阳离子交换树脂柱去除硫酸钴中大量的钴和其他金属离子,利用离子色谱仪对痕量氯离子进行测定.以碳酸钠（2.5 mmol/L）和碳酸氢钠（3.5 mmol/L）混合溶液作为淋洗液,SH-AC-1（200 mm×4.6 mm ID）阴离子分析柱分离,抑制电导检测器检测.氯离子浓度在0～10 mg/L范围与色谱峰面积有良好的线性关系,线性相关系数为0.999 1.样品的加标回收率在90％～111％之间,方法检出限为0.03 μg/mL,测定下限为0.000 6％.方法简便、快速,稳定性好,测定结果与国标方法对比相一致,符合化学试剂七水合硫酸钴中氯含量的测定要求.

A method for the determination of chlorine in cobalt sulfate heptahydrate （COSO4 · 7H2O） was established. The sample was dissolved in high pure water, and trace chlorine ions were deter-mined by ion chromatography after the large amounts of Co and other metal elements in the cobalt sul- fate were removed by cation exchange resin column. Sodium carbonate （2.5 mmol/L） and sodium bi- carbonate （3.5 mmol/L） mixture solution was used as eluent. The SH-AC-1 （200 mm×4.6 mm ID） anion analytical column was used for separation and suppressed conductivity conductor was used for detection. It was found that chlorine ions in the concentration range of 0--10 mg/L showed a good lin- ear relationship with its chromatographic peak area, with the correlation coefficient of 0. 999 1. The standard addition recovery was 90%-111%. The detection limit and limit of quantitation were 0.03 μg/mL and 0. 000 6% respectively. The method was simple, fast and stable and the experimental re- sults were consistent with those of national standard method, which could satisfy the requirements of the determination of chlorine in cobalt sulfate heptahydrate.