萃取动力学分析法的研究和应用Ⅵ.非催化法测定Ce(Ⅳ)

Study of extraction kinetic analysis and its application Ⅵ.determinstion of Ce(Ⅳ)by uncetalytic method

利用Ce(Ⅳ)在2mol/LHCl 介质中氧化二苯硫腙褪色的慢反应,用萃取平衡控制反应时间和水相中二苯硫腙的浓度,建立了非催化动力学分析法测定Ce(Ⅳ)的新方法。反应速度的检测是在620nm下测定反应前后CCl_4相中二苯硫腙吸光度的变化。方法的检测限为5.0×10^(-7) gCe(Ⅳ)·ml^(-1) ,线性范围为0. 5-5μgCe(Ⅳ)·ml^(-1)。对干扰严重的金属离子 Ag^+、Au^(3+)、Cu^(2+)、Hg^(2+)等可在 pH4-6条件下,用二苯硫腙的四氯化碳溶液萃取除去。将方法用于测定合成水样中Ce(Ⅳ),结果满意。

Based on the decolored reaction of Ce(Ⅳ)on the oxidation of dithizone in 2. 0 M HCl medium,a new uncatalytic kinetic method for the deter-mination of Ce(Ⅳ)has been developed.The reaction time and concentra- tion of dithizonein eaqueousphas are controled by extraction equilibrium. By means of monitoing the absorbance change in CCl_4 phase at 620nm, the reaction rate is obstained.The limit of detection is 5. 0×10^(-7) g Ce(Ⅳ)·ml^(-1) ,and range of the linearityin 0. 5-5μg Ce(Ⅳ)·ml^(-1) .The method has been applied to the determination of Ce(Ⅳ)in complex water sample.The results are satisfactory.