双波长分光光度法测定废水中痕量铬(Ⅵ)

Dual-wavelength spectrophotometric determination of trace chromium (Ⅵ) in waste water

在H2SO4介质中，铬（Ⅵ）与茜素蓝S（ABS）形成红色产物，据此建立了双波长分光光度法测定废水中痕量铬（Ⅵ）的新方法。测定波长为510nm，参比波长为575nm，表观摩尔吸光系数为7．4×10^4 L·mol^-1·cm^-1。方法的线性范围为0．4～1．0μg／mL，检出限为17．22ng／mL。方法用于工业废水中铬（Ⅵ）含量的测定，加标回收率为95．7％～103．2％。利用该方法分析废水中铬（Ⅵ）的含量与国家标准方法（二苯碳酰二肼分光光度法）的结果基本一致。

A novel determination method of trace chromium （Ⅵ） in waste water by dual-wavelength spectrophotometry was established based on the fact that chromium （Ⅵ） can react with alizarin blue S （ABS） to form red complex in H2SO4 medium. The detected wavelength was 510 nm while the reference wavelength was 575 nm , and the apparent molar absorptivity was 7.4 ×10^4 L·mol^-1·cm^-1. The linearity range for the determination of chromium （Ⅵ） was 0.4--1.0 μg/mL, with the detection limit of 17.22 ng/mL. The proposed method has been applied to the determination of chromium （Ⅵ） in industrial waste water with the recovery of 95.7%- 103.2%. The results were in coincidence with those obtained by national standard method （diphenylcarbazide spectrophotometry）.