离子色谱法测定水中总硬度

Determination of Total Hardness in Water by Ion Chromatography

采用离子色谱法测定水中钙、镁离子浓度,并以此计算水中总硬度。结果表明,钙离子在1.0~60.0mg/L范围内,线性相关系数0.9998,检出限0.022mg/L;镁离子在0.4~24.0mg/L范围内,线性相关系数0.9995,检出限0.004mg/L。测定样品中钙、镁及总硬度的加标回收率在91.9%~97.4%之间,相对标准偏差RSD为0.14%~0.23%。离子色谱法与EDTA-2Na滴定法测定总硬度结果进行对比,结果显示两者无显著性差异。该法具有简单方便、干扰少、准确可靠等优点,适合大批量样品的测定。

Total hardness in water were calculated by determining the concentration of Ca2+ and Mg2+ using ion chromatography. For the Ca2+,the linear range of the method was 1.0-60 mg/L(r=0.999 8),and the detection limit was 0.022 mg/L. For the Mg2+,the linear range of the method was 0.4-24.0 mg/L(r=0.999 5),and the detection limit was 0.004 mg/L.The average recovery rates of the samples were in the range of 91.9%-97.4%,and the relative standard deviation was 0.14%-0.23%.The results of EDTA-2Na titration method and ion chromatography method were compared,and there was no significant difference of total hardness values between the two methods.This method is simple,convenient,interference little,accurate and reliable,which is suitable for large quantities of samples.