薄层树脂相三元缔合体系分光光度法测定痕量钴(Ⅱ)  

Spectrophotometric determination of trace cobalt(Ⅱ) with thin layer resin phase based on a ternary complex system

作　　者：吕鹏飞[1] 李春香[2] 徐婉珍[2] 谢吉民[2] 闫永胜[2] 

机构地区：[1]平顶山工学院,河南平顶山467000 [2]江苏大学化学化工学院,江苏镇江212013

出　　处：《冶金分析》2007年第4期52-54,共3页Metallurgical Analysis

基　　金：科技部创新基金项目(03C26213200932);江苏大学高级人才基金(04JDG017)

摘　　要：在酸性介质中,阴离子交换树脂定量交换缔合,形成阴离子交换树脂(R+)-金属离子(Mn+)-硫氰酸盐(SCN-)三元缔合体系,该三元缔合体系最大吸收波长为630nm,与二元水相最大吸收波长相同,通过制作薄层测定了水中Co(Ⅱ)含量。本文讨论了树脂粒度及用量、交换时间、显色剂用量、酸度等因素的影响,研究了最佳反应条件。结果表明:体系的表观摩尔吸光系数为ε630=2.1×105L.mol-1.cm-1,Co(Ⅱ)的质量浓度在0～640μg/L范围内服从比尔定律,方法的检出限为8.8μg/L,灵敏度比水相光度法提高19倍。测定25mL溶液中10.0μgCo(Ⅱ),RSD为3.1%(n=6)。方法用于测定天然水中Co(Ⅱ)含量,与原子吸收光谱法比较,结果吻合。A new method for the determination of cobalt in water sample with thin layer resin phase spectrophotometry was established. In acid medium, a ternary association complex system which was formed by SCN , Co（Ⅱ） and strong alkalescence anion exchange resin had the maximum absorption at the wavelength of 630 nm. Due to the increasement of absorbance sectional surface and the n electron free space of the complex in the resin phase, the sensitivity was 20 times larger than that in water solution. The apparent molar absorptivity ε630 was 2.1 × 10^5 L· mol^-1· cm^-1. The RSD of the method was 3.1% （ n = 6 ） for determination of 10.0 μg cobalt in 25 mL solution. Beer＇ s law is obeyed in the range of 0 - 640 μg/L with detection limit of 8.8μg/L. As compared with AAS, the results for determination of cobalt content in actual water samples were satisfactory.

关 键 词：三元缔合体系 薄层树脂相 分光光度法 钴 

分 类 号：O657.3[理学—分析化学]