氨基黑10B退色分光光度法测定水中溴酸根离子

Study on the Fading Photometric Determination of Micro-amounts of Bromate with Amido Black 10B

在盐酸介质中,依据溴酸根离子氧化氨基黑10B退色的原理提出了测定水中溴酸根含量的新方法,研究了测定的最佳条件。最大吸收波长为690 nm,BrO3-浓度在0.5～4.5μg/mL内其浓度与吸光度呈良好线性关系,线性回归方程为A=0.153 33 C+0.026 56,相关系数为0.995 3,表观摩尔吸光系数为1.27×104L/(cm.mol)。该法适用于水中微量溴酸根离子测定。

A new photometric method for the determination of micro-amounts of bromate is proposed based on the oxidation of amido black 10B by bromate in hydrochloric acid medium in this paper. The optimal conditions were studied. The maxi- mum absorption of amido black 10B lies at 690 nm. A decrease of absorbance of amido black 10B resulted form its oxidation by bromate, and a linear relationship is established between the decrease of absorbance and bromate concentration of 0.5-4.5 μg/mL. The correlation coefficient was 0.995 3 and the apparent molar absorptivity was 1.27×10^4 L/（cm.mol）. The proposed method has been applied to the determination of micro-amounts of in water.