Stereo effects in the chemical ionization mass spectrometry of galanthamine epimers

Galanthamine and 2-epigalanthamine possess similar electron impact mass spe ctra (EI-MS), while their chemical ionization (CI) mass spectra with isobut ane, acetone and diethyl ether as reagent gas show significant differences in the relative intensities of [M + H](+) and [M + H - H2O](+) ions. Ioniza tion with amines indicates lower basicity of galanthamine, compared with it s epimer. Two modifications of a method for determination of the ratio gala nthamine to 2-epigalanthamine in mixtures were developed.