Detection of Iodine-containing Compounds on Paper Chromatograms

Abstract

Bowden, Maclagan and Wilkinson have described¹ the use of the cerie sulphate–arsenious acid reaction for the detection of micro-quantities of iodine-containing compounds on paper chromatograms. A difficulty encountered in this laboratory was the fading of the background colour due to the presence of traces of iodine in the atmosphere. This can be prevented by spraying the chromatograms, immediately on completion of the catalytic reaction, with a 1 per cent solution of o-phenylenediamine in acetone and drying in air. The stable chocolate-coloured background formed by reaction of excess ceric sulphate with the amine gives a greatly increased contrast with the white spots, and the life of the chromatogram is limited only by the decomposition of the cellulose by the acid present in the original reagent.