在β-环糊精存在下催化动力学光度法测定铬(VI)

Determination of Trace Chromium(Ⅵ) by Catalytic Photometry in the Presence of β-Cyclodextrin

在β-环糊精存在下,根据铬催化溴酸钾氧化罗丹明B的褪色反应,建立了测定痕量铬的新方法.实验结果表明:方法的最大吸收波长为575 nm,铬量在0.007～0.27 mg/L范围内符合比尔定律,表观摩尔吸光系数为1.95×105L.mol-1.cm-1.用于钢样中铬含量的测定,结果与认定值吻合.

A new catalytic spectrophotometric method for the determination of trace chromium（Ⅵ） was developed based on the oxidation of rhodamine B with potassium bromate catalyzed by chromium（Ⅵ） in the present of β-cyclodextrin.The result showed that the maximum absorbance wave length is at 575 nm.The beer’s law is obeyed in the range of 0.007-0.27 mg/L with apparent molar absorption of 1.95 × 105 L·mol^（-1）·cm^（-1）.The proposed method was applied to determination of trace chromium（Ⅵ） in steel samples and the results are agreement with certified values of samples.