Elution of Alkaloids from Citrate-buffered Paper Chromatograms

Abstract

ONE of the most satisfactory methods of paper chromatography of alkaloids is the butanol–citrate system introduced by Curry and Powell¹. It suffers, however, from the disadvantage that if one attempts to elute the alkaloid with chloroform for subsequent confirmatory tests, a certain amount of citrate is also extracted. This interferes with certain important colour tests, as the yellow colour which it gives with concentrated sulphuric acid modifies any colour given by the alkaloid. For example, morphine with the Marquis reagent gives a muddy brown instead of a clear violet.