离子缔合溶剂萃取分光光度法测定痕量铬

Determination of Trace Chromium by Ion Association Solvent Extract Spectrophotometry

Ｃｒ（Ⅵ）氧化Ｉ－离子产生Ｉ－３配阴离子，在硫酸介质中，Ｉ－３与罗丹明Ｂ阳离子形成离子缔合物，该缔合物能被苯等有机溶剂萃取，建立了一种测定痕量铬的新方法．缔合物表观摩尔吸光系数ε＝２．１×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，铬量在１．０－１２．０ｎｇ／ｍＬ范围内符合比耳定律，本法应用于人发中痕量铬的测定，结果满意．

A new spectrophotometric method of determining trace Chromium has been developed based on Chromium(Ⅵ)oxidating I - to I - 3, then I - 3 to form an ion association with Rhodamine B in a media of Sulfuric acid. The ion association could be extracted by organic solvent such as benzene.The method is very sensitive,the apparent molar absorptivity is 2.1×10 5L·mol -1 .cm -1 . Berrs Law is obeyed in the Cr(Ⅵ)concentration range of 1.0—12.0ng/mL, The method has been applied to the determination of chromium in hair with satisfactory results.