Cation Analysis by Thin - Layer Chromatography and Reflectance Spectroscopy

A procedure whereby reflectance spectroscopy can be employed for the analysis of substances resQlved on thinlayer plates was developed with the use of metal cation mixtures that had been separated on cellulose plates. A rapid method was devised whereby fourteen cations were separated and identified ~~ by their reflectance spectra after chromogenesis with a mixture of dithizone and 8-hydroxyquinoline. Further studies were carried out on three of these cations: copper, nickel, and zinc. Copper and nickel were determined in the presence of eleven other cations without experiencing any interferences by employing neocuproine and dimethylglyoxime, respectively, as chromogenic reagents. In the case of zinc, the use of 3,3'-dimethylnaphthidine was equally successful except in the presence of tin, cadmium, and iron. The optimu~ concentration and reflectance ranges and the maximum accuracy of these analyses were then deduced by applying two graphical methods to the data