溴酸钾氧化酸性铬深绿G褪色催化动力学光度法测定苯胺

Catalytic Kinetic Spectrophotometric Determination of Aniline Based On Fading Reaction of Acid Chrome Dark Green G Oxidized by Potassium Bromate

在硫酸介质中,溴酸钾能氧化酸性铬深绿G褪色使其吸光度下降,而苯胺的加入能明显地催化这一反应,其催化程度与加入苯胺的浓度有关,据此建立了酸性铬深绿G褪色催化动力学光度法测定痕量苯胺的新方法。考察了不同试验条件对催化反应灵敏度的影响,得到了最佳试验条件:硫酸2.0 mL,溴酸钾2.8 mL,酸性铬深绿G 1.0 mL,反应温度55℃,加热反应时间5 min。校准曲线的线性范围为20~120μg/L,线性回归方程为ΔA=0.0098+0.21C,相关系数R=0.9923。方法检出限为1.5×10^(-6) g/L。实验方法用于测定印染废水中苯胺,结果的相对标准偏差(RSD)分别为2.6%和2.1%;回收率分别为108.5%和105.3%。

Acid chrome dark green G could be faded via oxidation by potassium bromate and the absorbance decreased in sulfuric acid medium. This reaction could be catalyzed greatly by aniline and the catalysis degree is correlated with concentration of aniline. A new method of determination of aniline by catalytic kinetic spectrophotometry was established according to the above principle. The effects of different determination conditions on the catalytic reaction sensitivity were investigated. The optimal determination conditions were obtained by experiments： sulfuric acid 2.0 mL, potassium hromate 2.8 mL, acid chrome dark green G 1,0 mL, reacting at 55 ℃ for 5 rain. When the mass concentration of aniline was in range of 20- 120 μg/L, the linear regression equation of calibration curve was △A=0.0098＋ 0.21C with correlation coefficient of R=0.9923, and the detection limit of aniline in this method was 1.5 × 10^-6g/L. The proposed method was applied to the determination of aniline in dyeing wastewater. The relative standard deviations （RSD） were 2.6% and 2.1%, and the recoveries of standard addition were 108.5% and 105.3%.