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催化动力学分析是一种操作简便,设备简单,灵敏度高的分析法。方法的检出限一般为10~(-12)g·g~(-1)。文献作者对动力催化反应进行过较系统的研究。文献曾做过利用Fe(Ⅲ)催化H_2O_2-罗丹明B体系测定铁的工作。本文基于在稀H_2SO_4介质中,抗坏血酸存在下,Fe(Ⅲ)催化KBrO_3氧化偶氮胂Ⅲ,使溶液吸光度降低的变化,研究了测定超痕量铁的试验条件和干扰情况,建立了一种新的催化动力学光度法测定超痕量铁的方法。本法的桑德尔灵敏度为8.8×10~(-7)μg·cm~(-2),间接摩尔吸光系数为6.3×10~7L·mol~(-1)·cm~(-1).在0～14ng/25ml范围内符合比耳定律。对高纯锌和纯活性炭的测定结果令人满意。标准加入回收率为96.7～102.5%。
Catalytic kinetic analysis is an easy-to-use, simple device with high sensitivity. The detection limit of the method is generally 10 ~ (-12) g · g -1. Literature authors conducted a systematic study of catalytic reactions. The literature has done the use of Fe (Ⅲ) catalytic H_2O_2-Rhodamine B system for the determination of iron. In this paper, based on the change of absorbance of KBrO_3 oxidized arsenazo (Ⅲ) catalyzed by Fe (Ⅲ) in dilute H_2SO_4 medium with ascorbic acid, the experimental conditions and interference of ultra-trace iron determination were studied, and a new Catalytic Kinetic Spectrophotometric Determination of Ultra-trace Iron. Sensitivity of this method is 8.8 × 10 -7 μg · cm -2 and the indirect molar absorption coefficient is 6.3 × 10 -7 L · mol -1 · cm -1. Beer’s law is within 0 ~ 14ng / 25ml. The results of determination of high purity zinc and pure activated carbon are satisfactory. The standard recovery rate was 96.7 ~ 102.5%.