Separation of lithium, sodium and potassium present as sulphates and citrates by means of paper chromatography

Abstract

The technique of paper chromatography has been applied for the separation of the alkali metals present as sulphates and citiateh. The sulphates are made visible on the chromatogram by spraying the paper at first with barium chloride in 70% alcohol and then with Na-rhodizonate solution. The sulphate spots appear as yellow on reddish background by spraying the paper with an alcoholic solution of bromophenol blue made slightly acid with citric acid. There are different optimum proportions of water in its mixture with methanol, ethanol and acetone for the separation of the metals. These optimum proportions depend also on the nature of the salts used. The significance of the nonaqucous component of the mixture used for developing is briefly discussed.