【摘要】 基于在H2SO4介质中及加热的条件下,加入活化剂硫脲对亚铁氰化钾-番红花红T配位显色反应具有增敏作用。痕量Hg(Ⅱ)催化亚铁氰化钾配位交换番红花红T增敏显色反应显著增强,据此,建立了离子催化配位交换增敏显色反应动力学光度法测定痕量汞(Hg)的新光度分析法。研究了反应的最佳实验条件。催化反应(吸光度A)与非催化反应(吸光度A0)吸光度差值△A与Hg(Ⅱ)的质量浓度在0.0055～2.50μg/25 mL范围内呈良好的线性关系,检出限为1.39×10-10g/mL。测定了动力学参数,反应对Hg(Ⅱ)为一级反应,总反应为准一级反应。表观速率常数为4.32×10-4/s,表观活化能为57.4 kJ/moL。该方法用于水样和人发中痕量汞Hg(Ⅱ)的测定,其回收率为98%～101%,符合痕量分析的要求。更多还原

【Abstract】 When heated in a dilute sulfuric acid medium,the color reaction of the potassium ferrocyanide-safranine T ligand can be enhanced by the activation agent thiourea.Also,Hg(II) catalyzing the color reaction of potassium ferrocyanide ligand exchanging safranine T can be greatly enhanced.Based on this,a new method for the determination of trace Mercury(Ⅱ) with ion catalyzing ligand exchange sensitized color kinetic spectrophotometry was established.The optimum experimental conditions were studied.The absorbency difference △A between non-catalytic reaction(absorbency A0) and catalytic reaction(absorbency A) remained good linear relationship with the mass concentration ρ of Hg(Ⅱ) in the range of 0.0055~2.50 μg/25 mL.The detection limit was 1.39×10-10 g/mL.The kinetic parameters were determined,and the results showed that the reaction was the first order to Hg(II) and pseudo first order to the total reaction.The apparent rate constant was 4.32×10-4 /s and the apparent activation energy was 57.4kJ/mol.This method has been applied to the determination of trace Hg(Ⅱ) in water samples and human hair with the recoveries of 98%~101%,which fulfilled the trace analysis requirements.更多还原