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提出了动力学光度法测定铱。在磷酸 -氯化钠介质中 ,Ir( )催化高碘酸钾氧化乙基罗丹明 B( ERB)形成褪色化合物 ,适宜条件为 c Na Cl=0 .0 2 mol/ L ,c H3PO4 =0 .1 0 mol/ L ,c KIO4 =2 .0× 1 0 - 3mol/ L ,c ERB=1 .7× 1 0 - 5mol/ L ,I=0 .0 2 ,90℃。铱浓度在 0 .4～ 32μg/L范围校正曲线成直线 ,检出限为 4.0× 1 0 - 10 g/ m L,对 2 0 μg/ L铱测定 1 1次的 RSD为1 .55% ,体系至少稳定 8h。考察了 30多种共存离子的影响。本法满意地用于某些冶金产品和矿石中铱的测定。铱催化反应对 Ir( )、ERB、KIO4 和 H3PO4 均为一级反应 ,表观活化能为 75.82 k J/ mol,探讨了反应机理
Kinetic spectrophotometry was proposed for the determination of iridium. Ir () catalyzed oxidation of ethylrhodamine B (ERB) by potassium periodate in phosphoric acid-sodium chloride medium to form fading compounds. The optimum conditions were as follows: NaCl = 0.2 mol / L, c H3PO4 = 0. 10 mol / L, c KIO4 = 2.0 × 10 3 mol / L, c ERB = 1.7 × 10 5 mol / L, I = 0.02, 90 ℃. The calibration curve of iridium concentration in the range of 0.4 ~ 32μg / L was linear with the detection limit of 4.0 × 10 ~ 10g / m L, and the RSD of 1 1 times of 20μg / L iridium was 1.55% The system is stable at least 8h. Examined the impact of more than 30 kinds of coexisting ions. This method is satisfactory for the determination of iridium in some metallurgical products and ores. The iridium catalytic reaction was a first order reaction for Ir (), ERB, KIO4 and H3PO4 with an apparent activation energy of 75.82 kJ / mol. The reaction mechanism