三溴偶氮胂褪色光度法测定土壤及化学试剂中铬(Ⅵ)

Determination of Chromium(Ⅵ) in Soil Samples and Chemical Reagent by Tribromoarsenazo Fading Spectrophotometry

在 0 .4 8mol/L硝酸介质中 ,Cr( )与三溴偶氮胂 (TBA)发生褪色反应 ,该反应的表观摩尔吸光系数ε516nm=1.0 4× 10 5L· mol-1· cm-1,铬 ( )含量在 0— 1.0× 10 -4 g/L范围内呈良好线性关系。该法用于土样及化学试剂中 Cr( )的测定 ,结果令人满意。

In the medium of 0.48mol/L nitric acid, chromium(Ⅵ) reacts with tribromoarsenazo to produce color-fading reaction. Based on this fact, chromium (Ⅵ) was determined. The apparent molar absorptivity is ε 516nm=1.04×10 5 L·mol -1·cm -1. The linear relationship is shown over the range of 1.0×10 -4g/L of chromium(Ⅵ). The method was used for the analysis of chromium(Ⅵ) in the soil sample and chemical reagent.