THE NON–SPECIFICITY OF DRAGENDORFF'S REAGENT IN THIN LAYER CHROMATOGRAPHY

Abstract

Dragendorff's reagent is known to produce positive reactions with certain non-alkaloidal compounds. For compounds not possessing nitrogen, false positives have been attributed to the presence of conjugated carbonyl or lactone groupings. We report that the range of compounds producing false positives is far greater than generally realised. Compounds such as the common plant sterols and tri-terpenes are readily detected by Dragendorff's spray and it is possible to correlate the limits of detectability with the chemical nature of the compounds detected. The effect of intensifier sprays on the production of alkaloid false positives is also considered.