铜钨杂多酸-罗丹明B光度法测定铜

Spectrophotometric Determination of Copper by Tungstocoppate Heteropoly Acid and Rhodlamine B

研究了在ＰＶＡ存在下铜钨杂多酸－罗丹明Ｂ离子缔合物的形成条件，提出了光度测定铜的新方法，在０．９６ｍｏｌ／ＬＨ２ＳＯ４介质中，离子缔合物的最大吸收波长为５７０ｎｍ．表观摩尔吸光系数为１．５３×１０６Ｌ·ｍｏｌ－１·ｃｍ－１，方法选择性尚好，可不经分离直接用于各种水样，人发等样品中铜的测定，结果满意。

A new spectrophotometric method for the determination of copper is established by the reaction of rhodamine B(RB) cation with tungsto coppate heteropoly anion to from a ion association complex in the presence of polyvinyl alcohol (PVA). Maxium absorbance of the ion association complex is at 570nm in the medium of 0.96 mol/L H 2SO 4. the apparent molar absorptivity is 1.53×10 6L\5mol -1 \5cm -1 . Beer′s law is obeyed for 0￣0.5 μ g/25mL of copper. The limit of detection is 0.36ng/mL ( n =12). A 0.018 μ g/mL copper sample is analysed eleven times and the relative standard deriation is 0.83%. The ion associiation complex is stable for at least 150 h. The influence of over 40 diverse ions was examined. Most common ions do not interfere. The method was used to the spectrophoto metric determination of copper in natrual water, running water, precipitation, human hairs, carrot and toptis with satisfactory results.