Burke R W, Deardorff E R
Institute for Materials Research, National Bureau of Standards, Washington, D.C., U.S.A. 20234.
Talanta. 1970 Apr;17(4):255-64. doi: 10.1016/0039-9140(70)80211-9.
In aqueous ethanol cobalt(II), nickel(II) and copper(I) react instantaneously with 2,3-quinoxalinedithiol at pH 2 to form strongly coloured complexes exhibiting absorption maxima at 510, 606 and 665, and 625 nm, respectively. At pH 6 the reaction of copper can be virtually eliminated, while the cobalt and nickel reactions show only small decreases in sensitivity. This behaviour has been made the basis of a rapid method for the simultaneous determination of these three elements. The absorbances of the complexes have been found to be additive for all combinations of these elements in which the individual concentrations have been varied from approximately 0.1 to 1 ppm. A least-squares estimate of the concentration of any of the elements may be readily obtained by using a simple linear equation based on the absorbance readings and a set of constants derived from the spectrophotometric data. The analyses of seven synthetic solutions and four NBS Standard Reference Materials yielded a maximum error of 6.0% and an average error of 1.6%.
在乙醇水溶液中，钴（II）、镍（II）和铜（I）在pH值为2时与2,3-喹喔啉二硫醇瞬间反应，形成颜色强烈的配合物，其最大吸收波长分别为510、606、665和625 nm。在pH值为6时，铜的反应几乎可以消除，而钴和镍的反应灵敏度仅略有下降。这一特性已成为同时测定这三种元素的快速方法的基础。已发现，对于这些元素的所有组合，配合物的吸光度具有加和性，其中各元素的浓度在约0.1至1 ppm之间变化。通过使用基于吸光度读数和一组由分光光度数据得出的常数的简单线性方程，可以轻松获得任何一种元素浓度的最小二乘估计值。对七种合成溶液和四种美国国家标准局标准参考物质的分析得出，最大误差为6.0%，平均误差为1.6%。
