粉煤灰中微量铬的光度法测定

Spectrophotometric Determination of Trace Chromium in Fly Ash

在HNO3 介质中利用Cr2 O2 - 7氧化偶氮胂Ⅲ的褪色反应 ,对粉煤灰中的痕量铬进行测定。结果表明 ,在 3 2mol·L- 1 的硝酸介质中褪色反应具有高的灵敏度 ,反应产物的最大吸收波长为 52 0nm ,摩尔吸光系数为1 9× 1 0 6 L·mol- 1 ·cm- 1 。铬 (Ⅵ )含量在 0 0～ 40 0 μg·L- 1 范围内服从比耳定律。该法用于测定粉煤灰中的铬 ,得到了满意的结果。

In HNO3 medium the fading reaction of arsenazo III oxidated with Cr2O72- was used as to determine trace Cr in fly ash containing Cr. The results show that the fading reaction has high sensitivity in the medium of 3.2 mol(.)L(-1) nitric acid, the molar absorptivity of 3.9 x 10(6) L(.)mol(-1.)cm(-1) at 520 nm, and Beer's law is obeyed for Cr (VI) in the range of 0.0similar to40.0 mug(.)L(-1). Contents of Cr in fly ash were determined with satisfactory results.