Mass spectra of iso-cinchona- and halogenated cinchona alkaloids

The electron impact ionisation (EI) and electrospray ionisation (ESI) mass spectra using in-source collision-induced dissociation of nine different ci nchona alkaloid derivatives [iso-cinchona alkaloids (ethereal isomers) and 10-Br(Cl) containing cinchona compounds] have been studied. In the case of the EI method for iso-cinchona alkaloids the observed fragmentation directi ons are as follows: isomerisation of the cyclic ethers to the corresponding C9 ketone, the formation of [M - 15](+), [M - 29](+) and [M - 57](+) fragm ents as a result of the loss of methyl, ethyl and butyl radicals, and the c leavage of the C8-C9 bond. The fragmentation of the compounds containing C1 0-Br(Cl) bonds started with the scission of this bond. The primary bond rup ture is followed by the fragmentation of the primary product into two parts across the C8-C9 bond, In the case of the ESI method at low capillary exit voltage only the peak of the protonated molecule ([M + H](+)), and in a si gnificantly lower abundance, the peak of the [M + 2H](2+) ion can be observ ed. Increasing the capillary exit voltage causes fragmentation to occur. Fo r iso-cinchona alkaloids the main direction is the cleavage of C8-C9 bond. For the C10-Br(Cl) compounds, the primary fragmentations are the cleavage o f the C9-O and C10-Br(Cl) bonds. Fragmentation pathways are discussed.