Fast stereoselective reactions in electrosprayed Co(II)eurotransmitter nanodropletsf

摘要

Collision induced dissociation (CID) of the m/z 479 ion, formed by ESI of Co(NO_3)_2-CH_3OH solutions with either pure (1S,2S)-( + )-N-methylpseudoephedrine or its mixtures with (1S,2S)-( + )- or (1R,2S)-(-)-ephedrine, provides compelling evidence for fast, stereoselective reactions in Co(II)eurotras-mitter(s) aggregates during solvent evaporation of the ESI droplets. Electrospray ionization (ESI) has become a well integrated tool for mass spectrometry (MS) because of its capability to put in the gas phase a variety of non-volatile analytes, such as peptides, proteins, drugs, polymers, organometallics, inorganics, and even viruses and bacteria, as well as noncovalent supramolecular aggregates. However, the processes and mechanisms that must occur for production of these gas-phase species from bulk solutions are inadequately understood. The problem arises from the intrinsic difficulties in observing the formation and the behaviour of submi-cron charged droplets from solution and, more importantly, how the concentration and the distribution of the analytes in these droplets change during the time evolution of the electro-spray plume.