苏丹红Ⅰ褪色分光光度法测定环境水体中六价铬

Determination of Chromium(Ⅵ) in Environment Samples with Sudan Ⅰby the Fading Spectrophotometric

在盐酸介质中,依据六价铬离子(Cr(Ⅵ))氧化苏丹红Ⅰ使其褪色的原理提出了测定Cr(Ⅵ)离子的新方法,确定了最优的测定条件。在485 nm处,Cr(Ⅵ)离子在0.2～2.6μg/mL范围内符合比尔定律,线性回归方程为A=0.207 0C+0.002 35,相关系数为0.996 0,表观摩尔吸光系数为6.09×104L/(cm.mol)。该方法可用于水样中的微量Cr(Ⅵ)离子的测定,回收率为97.1%～100.3%,RSD小于3.0%。

A new spectrophotometric method for the determination of micro-amounts of Chromium(VI) was proposed based on the oxidation of Sudan Ⅰ by Chromium(Ⅵ) in hydrochloric acid medium.The optimal conditions were studied.The maximum absorption of Sudan Ⅰ was at 485 nm.The decrease of absorbance of Sudan Ⅰ resulted from its oxidation by Chromium(Ⅵ),and the linear relationship was established between the decrease of absorbance and Chromium(Ⅵ) concentration of 0.2～2.6 μg/mL.The equation of linear regression was A=0.207 0 C+0.002 35,coefficient of correlation was 0.996 0,apparent molar absorption coefficient was 6.09×104L/cm.mol.The proposed method had been applied to oletermine Chromium(VI) in water samples,and the recovery rate was 97.1%～100.3% and the RSD was less than 3.0%.