火焰原子吸收法测定钾、钠离子浓度硝酸铯加入量讨论

目的 探讨硝酸铯作为电离抑制剂对钾钠溶液的电离影响,寻求其在工作场所空气有毒物质测定中的最佳加入量。 方法 对比《水质钾和钠的测定火焰原子吸收分光光度法》(GB 11904-1989),采用火焰原子吸收分光光度法,在仪器最佳检测条件下,做出标准曲线,对方法检出限、精密度和准确度进行测试,并对其抑制作用结果进行统计分析。 结果 选取铯离子质量浓度为341 mg/L、682 mg/L时为工作场所空气中(钠、钾)及其化合物测定的最佳加入量。加入特定浓度的硝酸铯后,钠离子曲线的相关系数为0.999 6,线性范围为0.0~5.0 μg/mL,检出限为0.007 μg/mL,最低检出浓度为0.001 mg/m3;钾离子曲线的相关系数为0.999 4,线性范围为0.0~10.0 μg/mL,检出限为0.015 μg/mL,最低检出浓度为0.002 mg/m3。 结论 与不加入电离抑制剂相比,加入适量硝酸铯后检测方法的灵敏度更高。

Optimizing value of cesium nitrate in measurement of potassium and sodium with FAAS

Objective The added value of cesium nitrate, as the ionization inhibitor, on the ionization of potassium and sodium solution by flame atomic absorption spectrophotometry was discussed. Based on method described by the GB 11904-89 "the Determination of Potassium and Sodium in Water by Flame Atomic Absorption Spectroscopic", the addition of cesium nitrate in determination of airborne toxic substances in workplaces was revised. Methods Under the optimized condition of testing instrument, the standard curve,detection limit, precision and accuracy were tested, and the inhibition results were statistically analyzed. Results The optimized concentrations of cesium ion were 341 mg/L and 682 mg/L respectively for the determination of sodium and potassium. After addition of cesium nitrate, the correlation coefficient of sodium curve was 0.999 6, the linear range was 0.0-5.0μg/mL, the detection limit was 0.007μg/mL and the lowest detection concentration was 0.001 mg/m3. For Potassium, the correlation coefficient was 0.999 4, the linear range was 0.0-10.0μg/mL, the detection limit was 0.015μg/mL and the lowest detection concentration was 0.002 mg/m3. Conclusion The optimized value of cesium nitrate as the ionization inhibitor could improve the sensitivity.