Rh(Ⅲ)-KIO_4-孔雀绿体系催化动力学光度法测定痕量铑  

Catalytic kinetic spectrophotometric determination of trace rhodium with Rh(Ⅲ)-kIO_4-malachite green system

作　　者：王洪福[1] 魏成富[1] 何黎明[1] 周建[1] 

机构地区：[1]绵阳师范学院化学与化学工程学院,绵阳621000

出　　处：《分析试验室》2008年第11期98-101,共4页Chinese Journal of Analysis Laboratory

摘　　要：在HCl介质及加热95℃的条件下,Rh（Ⅲ）对KIO4氧化孔雀绿的褪色反应有明显的催化作用,研究了指示反应的最佳反应条件和动力学参数,据此建立了催化动力学光度法测定痕量铑的新方法。非催化反应吸光度A0与催化反应吸光度A之间的差值ΔA与Rh（Ⅲ）质量浓度在0.004-0.060μg/mL范围内具有良好的线性关系,检出限为5.98×10^-10g/mL。反应为准一级反应,表观速率常数为7.67×10^-4s^-1,表观活化能为58.20 kJ/mol。该方法用于分子筛催化剂和活性炭中痕量铑的测定,回收率在95.8%-106.6%之间,符合痕量分析测定的要求。In hydrochloric acid and at 95 ℃ rhodium （ Ⅲ ） can catalyze the depigrnentation reaction of potassium periodate oxidizing malachite green. The optimal experimental conditions have been discussed and based on the optimal experimental conditions a new method of catalytic kinetic spectrophotometric determination of rhodium has been established. The absorbency difference △A and the concentration of rhodium （ Ⅲ ） remains good linear relationship in 0.04-0.06μg/mL, and the detection limit is 5.98 - 10^-10 g/mL. The dynamic parameter is also measured, suggesting that this reaction is a first order reaction. The apparent rate constant is 7.67 × 10^-4 s^-1, and the apparent activation energy is 58.20 kJ/mol. The method has been applied to the determination of trace amount of rhodium in molecular sieve catalysts and active carbon and resulted with a recovery rate between 95.8% to 106.6% which meets the requirement of trace amount analyst determination.

关 键 词：Rh(Ⅲ) KIO4 孔雀绿 催化动力学光度法 

分 类 号：O657.3[理学—分析化学]