Collision induced dissociation (CID) of the m/z 479 ion, formed by ESI of Co(NO3)2-CH3OH solutions with either pure (1S,2S)-(+)-N-methylpseudoephedrine or its mixtures with (1S,2R)-(+)- or (1R,2S)-(-)-ephedrine, provides compelling evidence for fast, stereoselective reactions in Co(II)/neurotrasmitter(s) aggregates during solvent evaporation of the ESI droplets.