铬(Ⅵ)-碘化钾-甲基紫-聚乙烯醇体系分光光度法测定废水中痕量铬

Determination of Trace Chromium ( Ⅵ ) by Spectrophotometry with Chromium(Ⅵ)-Potassium Iodide-Methyl Violet-Polyvinyl Alcohol System

研究了铬（Ⅵ）-碘化钾-甲基紫-聚乙烯醇高灵敏显色体系测定铬（Ⅵ）的新方法。实验结果表明：在最大吸收波长540nm处，铬（Ⅵ）质量浓度在0～0．8mg／L范围内符合朗伯-比耳定律，表观摩尔吸光系数为6．59×10^4L／（mol·cm）；采用该法测定铬（Ⅵ）标准试样与镀铬废水，测定结果与国家标准分析方法的结果相吻合，加标回收率为94．0％～103．0％；测定11次0．4mg／L铬（Ⅵ），相对标准偏差为2．1％。

A new method for Cr（ Ⅵ ） determination with the highly-sensitive color developing system of Cr （Ⅵ）-potassium iodide-methyl violet-polyvinyl alcohol was studied. The experimental results show that： The maximum absorption wavelength is 540 nm; The reaction accords with Beer＇s law when the mass concentration of Cr（Ⅵ） is 0 -0.8 mg/L with 6.59 × 10^4 L/（mol · cm） of ：molar absorption coefficient; The determination results of Cr（ Ⅵ ） standard sample and chromium plating wastewater by this method are close to those by the national standard analysis method, and the recoveries are in the range of 94.0% - 103.0% ; The RSD is 2.1% for 0.4 mg/L Cr（Wl） （n = 11）.