On the structure of water-alcohol and ammonia-alcohol protonated clusters

J Am Soc Mass Spectrom. 1993 Jun;4(6):507-12. doi: 10.1016/1044-0305(93)80009-N.

Abstract

Collision-induced dissociation (CID) of protonated ammonia-alcohol and water-alcohol heteroclusters was studied using a triple quadrupole mass spectrometer with a corona discharge atmospheric pressure ionization source. CID results suggested that the ammonia-alcohol clusters had NH: at the core of the cluster and that hydrogen-bonded alcohol molecules solvated this central ion. In contrast, CID results in water-alcohol clusters showed that water loss was strongly favored over alcohol loss and that there was a preference for the charge to reside on an alcohol molecule. The results also indicated that a loose chain of hydrogen-bonded molecules was formed in the water-alcohol clusters and that there appeared to be no rigid protonation site or a fixed central ion. (J Am Soc Mass.