Study of solvent-solvent interaction by paper chromatography. I. Dimethyl sulphoxide-water system

Summary The interaction between dimethyl sulphoxide (DMSO) and water, occurring when the two liquids are mixed together, has been studied: 1. by the measurement of the rate of migration of the different solvent mixtures, over the whole concentration range, on paper chromatograms, and 2. by observing the paper chromatographic behaviour of hexacyanoferrate II anions when these mixtures are used as mobile phases. The rate of migration gives a very pronounced maximum at the solvent concentration which corresponds to the composition DMSO·H₂O. The chromatographic behaviour of the hexacyanoferrate II ion besides confirming this conclusion shows the existence of three distinct zones of differing solvent structure and solvating behaviour.