ABSTRACT
Anybody who starts with the chromatography of alkaloids faces serious problems, many of them relating to the properties of these compounds. Sometimes the difficulty begins with the choice of solvent to extract the base from the plant or to dissolve the sample. Special emphasis has been placed on dissociation properties because the majority of alkaloid analyses are carried out by liquid chromatography with the prevailing share by reversed phase or ion pair chromatography. The dissociation of alkaloids in aqueous mobile phases is extraordinarily important in reversed phase liquid chromatography and ion pair reversed phase liquid chromatography. The acidity scale for amphiprotic solvents has been defined in a similar way as that for water, as this reference state involves an infinitely diluted solution in the given solvent, with an ionic strength approaching zero. Evidently at a given composition of phosphate buffer the addition of methanol suppresses the protonation of papaverine.
