溴酸钾 番红花红O阻抑动力学光度法测定痕量铑

在10 mo1/L的硫酸介质和95℃热水浴中，痕量铑对KBrO3氧化番红花红O变色反应有很强的抑制作用，据此，建立了阻抑动力学光度法测定痕量铑的新方法并测定了有关动力学参数。在选定的试验条件下，方法的线性范围是02～08 ng/mL，检出限为193×10-11 g/mL，表观活化能为1182 kJ/mol，阻抑反应对硫酸和铑都为一级反应。方法用于测定催化剂中铑，测定结果与SnCl2光度法的测定结果一致，相对标准偏差 (RSD)为27%和29% 。

Determination of trace rhodium by potassium bromate-safranine O inhibition kinetic spectrophotometry

In 1.0 mol/L sulfuric acid medium and hot water bath at 95 ℃,trace rhodium  had strong inhibition action on the fading reaction of safranine O oxidized by KBrO3.Based on this,a new determination method of trace rhodium  by inhibition kinetic spectrophotometry was established.Moreover,the related kinetic parameters were measured.Under the selected experimental conditions,the linear range of method was 0.2-0.8 ng/mL,the detection limit was 1.93×10-11 g/mL,and the apparent activation energy was 118.2 kJ/mol.The inhibition reaction was first order reaction for both sulfuric acid and rhodium.The proposed method was applied to the determination of rhodium in catalyst.The found results were consistent with those obtained by SnCl2 photometry.The relative standard deviations(RSD) were 2.7% and 2.9%.