New results on the mass spectra of cinchona alkaloids

The electrospray ionization (ESI) mass spectra of 16 cinchona alkaloid comp ounds were studied for the first time. The electron ionization (EI) spectra of 22 cinchona alkaloids were also recorded, 14 of which had not been exam ined previously. In the case of EI the characteristic direction of the frag mentation is the scission of the C8-C9 bond. Under EI the cleavage of the C 4'-C9 bond occurs only in the case of hydrogenated cinchona alkaloids, wher eas the C9-O bond cleavage can be observed in the case of ester and ether d erivatives, At a low capillary exit voltage (CapEx) in the ESI measurements there is no fragmentation, and only the [M + H](+) and in some cases the d ouble protonated [M + 2H](2+) ions can be detected. On increasing the CapEx the characteristic primary direction is the cleavage of the C9-O bond, whi ch was observed in the case of epialkaloids and esterified or etherified ci nchona derivatives, respectively. Copyright (C) 2000 John Wiley & Sons, Ltd .