The fragmentation of the cluster ion,A_1+HCL+A_2+H~+ of amine bases A_1 and A_2,is studied by the BEBE type tandem mess spectrometer.The cluster ion,A_1+HCL+A_2+H~+ ,is generated by the fast atom bombard-ment(FAB) ionization of mixture of two hydrochlorides of amines.The precursor ion is selected by the first analyzer (BE) and teh product ions are scanned by the second analyzer (B/E linker scanning).The fragmentation of ,A_1+HCL+A_2+H~+ yields two protonated monomers,,A_1+HCL+A_2+H~+ ,and protonated heterodimer,A_1+H+A_2~+.The relative abundances of A_1+H}~+ andA_2+H~+ from the fragmentation of A_1+HCI+A_2+H~+ are found to be related to their relative proton affinities and are used to determine the proton affinities (PAs) of methamphetamine and its analoge.The PA of methamphetamine is estimated to be 965 KJ/mol.
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