Quantitative Paper Chromatography on Mixed Solutions of Nickel and Cobalt, and Determination of both Elements

Abstract

THE chromatographic procedure used in this work is as follows: Whatman paper No. 1 cut into 25 cm. × 1 cm. strips. Solutions to be determined (50 per cent by vol. hydrochloric acid) are taken from automatic horizontal burettes¹. The solutions contain the desired amount (γ) of each cation in 0.01 ml. This volume of solution is deposited on the paper strip at 3.5 cm. distance from its top, and the drop is rapidly dried at 35–40° C. This is to ensure the smallest possible salt spots. The strips carrying the salt spots and others containing hydrochloric acid (50 per cent) (0.01 ml.) are developed in parallel in a presaturated closed vessel. Presaturation is reached by leaving cotton wool soaked in the solvent chosen in the vessel overnight. The platform from which the paper strips will hang (downward development) is also provided with soaked cotton wool. The experiments are carried out in a room the temperature of which is controlled by thermostat (20° C.), on wooden tables.