A comparison of reversed-phase and partition high-performance liquid chromatography of some digitalis glycosides.

Comparison of the data for adsorption and reversed-phase chromatography of digitalis glycosides shows the complementary nature of the two modes of separation. The correct choice for a particular problem should make possible a rapid and good separation with simple isocratic systems. Detection limits vary between 10 and 100 ng per injection and permit the analysis of by-products even in low-dosage pharmaceutical formulations. Quantitation is easily possible with both chromatographic techniques using external standardization. The reproducibility for repetitive chromatograms is about 1% relative standard deviation for manual injections by loop injectors and is even significantly better for automatic injection. Reversed-phase chromatography can offer some advantages with regard to sample preparation of pharmaceutical formulations.