The Examination of Gelatin Extracts and Polythionates by means of Paper Electrophoresis

Abstract

The thiosulphate, tri-, tetra-, penta- and hexa-thionate ions have been shown to have decreasing mobilities during paper electrophoresis. Four polythionate ions higher than S₆O₆ have been found in a hydrophilic sulphur sol. The movement of anions is much retarded and made erratic by the presence of relatively large amounts of inorganic salts in the solution applied to the paper. Protein in the applied solution does not interfere with the movement of anions if the paper is buffered to an appropriate pH. The earlier conclusion that the “natural” sensitizers of gelatin are inorganic ions has been confirmed. Thiosulphate and tetrathionate have been found in the extract of a particular bone gelatin. Two anionic sensitizers have been found in the extract of a hide gelatin; one is probably tetrathionate and the other less certainly, a higher polythionate. It is suggested that sensitizers may be produced in photographic gelatins by autoxidation or oxidation of SO₂. Suitable preparative methods and sensitizing and chromatographic data are indicated for the polythionates.