离子色谱法同时测定水中6种可溶性阳离子含量

Ion Chromatography for Simultaneous Determination of 6 Kinds of Soluble Cations in Water

为准确测定水中可溶性阳离子含量,对流动相配比、流速及进样量等离子色谱仪色谱条件进行了优化改进。利用Dionex ICS-1100离子色谱仪,选择亲水性强的Ion Pac CS12A阳离子交换柱(250 mm×4 mm)作为分离柱,采用22.0 mmol/L甲基磺酸为流动相,流速为1.0 mL/min,进样量为25μL,可快速准确地同时测定水中Li^(+)、Na^(+)、NH_(4)^(+)、K^(+)、Ca^(2+)和Mg^(2+)等阳离子含量,在13 min内能够快速完成检测,分析效率较常规离子色谱法提高了28%。优化后的方法线性相关性好(r>0.999),检出限低(0.01~0.02 mg/L),精密度高(RSD为0.2%~3.2%),加标回收率范围为90.0%~107.3%,有证标准物质测定结果在其置信区间之内,相对误差范围为2.4%~6.2%,测定结果准确,适合批量样品中阳离子的检测。

To accurately determine the content of soluble cations in water,the testing conditions of ion chromatograph such as ratio of mobile phase,flow velocity and injection volume were optimized.The contents of the cations such as Li^(+),Na^(+),NH_(4)^(+),K^(+),Ca^(2+)and Mg^(2+)in water could be rapidly and accurately determined simultaneously by Dionex ICS-1100 ion chromatograph under the following testing conditions:Ion Pac CS12A cation exchange column(250 mm×4 mm)with strong hydrophilicity as the separation column,methyl sulfonic acid with concentration of 22.0 mmol/L as the mobile phase,flow velocity of 1.0 mL/min and injection volume of 25μL.The detection was completed within 13 min,and the analytical efficiency was improved by 28%compared with conventional ion chromatography.The optimized method had good linear correlation(r>0.999),low detection limit(0.01-0.02 mg/L)and high precision(RSD 0.2%-3.2%).The recovery rates ranged from 90.0%to 107.3%.The determination results of certified reference substances were within the confidence interval,and the relative error range was 2.4%-6.2%,indicating that the method was accurate and suitable for detection of cations in batch samples.