在硫酸介质中,痕量钌能灵敏地催化溴酸钾氧化吖啶黄褪色,据此建立了一种测定痕量钌的新方法.研究了该催化褪色反应的最佳反应条件并测定了动力学参数.在选定的条件下钌的质量浓度在2～20 μg/L范围与催化反应和非催化反应的吸光度差有良好的线性关系,线性相关系数等于0.998 8,方法的检测限为5.33×10-8 g/L.测得反应速率常数为4.83×10-5 s-1,表观活化能为60.69 kJ/mol.试验了近40种共存离子对钌的测定影响,除Th(Ⅳ)、Pd(Ⅱ)、Pt(Ⅳ)、Rh(Ⅲ)、Ir(Ⅳ)的允许量较少外,其他离子的允许量均在钌量的10倍以上.将本测定方法与蒸馏分离法相结合成功地测定了矿石和冶金产品中钌,测定结果的相对标准偏差小于1.8％(n=6),加标回收率在98.8％～102.3％之间.%A new catalytic spectrophotometric method for the determination of Ru(Ⅲ) was developed,based on the catalytic effect of trace Ru on the oxidation of acridine yellow by potassium bromate in the medium of sul-furic acid. The optimal experimental conditions and kinetic dynamics parameters were investigated. Under the optimal experimental conditions, Ru(Ⅲ) had a good linear relationship with absorbance difference AA of the catalyzed reaction and uncatalyzed one in the range of 2-20 μg/L. The coefficient of correlation was 0. 998 8 with a detection limit of 5. 33 × 10-8 g/L. Moreover, the apparent rate constant and activation energy were 4. 83×10-5 s-1 and 60. 69 kJ/mol,respectively. The effect of 40 coexisting ions on the determination of 10 μg/L Ru(Ⅲ) was tested. Other ions were allowed at above 10 times except the allowed amount of Th(Ⅳ) ,Pd(Ⅱ), Pt (Ⅳ), Rh(Ⅲ), Ir(Ⅳ) was no more than 5 times. Ru in ore and metallurgical product had been determined by proposed method combined with distilling separation,with relative standard deviation of less than 1. 8 % and recovery of 98.8 %-102. 3 %.
展开▼
