Colour Reagents for the Paper Chromatography of Di- and Tri-hydroxy Phenols

Abstract

VARIOUS colour-producing spraying reagents have been developed for the detection of di- and tri-hydroxy phenols on paper chromatograms. Excellent results are obtainable with the diazotized sulphanilic acid of Evans, Parr and Evans¹ and the phospho-molybdic acid reagent of Riley². Bate-Smith^3,4 applied Partridge's⁵ ammoniacal silver nitrate reagent for furnishing diagnostic evidence regarding the position and number of hydroxy groups and also used ultra-violet light, both in the presence and absence of ammonia vapour, to obtain useful information. The majority of the above class of C₆ compounds give characteristic coloured spots with a 2 per cent aqueous ferric chloride spray^3,4, although meta- and para-hydroxy phenols (for example, orcinol, phloro-glucinol, resorcinol and hydroquinone) show ill-defined greyish spots.