Collision-induced dissociation studies of protonated alcohol and alcohol—water clusters by atmospheric pressure ionization tandem mass spectrometry. 1Methanol

✍ Scribed by Z. Karpas; G. A. Eiceman; C. S. Harden; R. G. Ewing; P. B. W. Smith

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 904 KB
• Volume: 29
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/oms.1210290402

✦ Synopsis

Cluster size distribution and collision-induced dissociation (CID) studies of protonated methanol and protonated methanol-water clusters yield information on the structure and energetics of such ions. Ions were formed at atmospheric pressure in a corona discharge source, and were subjected to CID in the center quadrupole of a triple quadrupole mass spectrometer. Cluster ions containing up to 13 molecules of methanol and/or water were observed and examined using CID experiments. The CID of all (CH,OH), -H,O * H + clusters, where n ,< 8, showed that water loss was statistically favored over methanol loss and that the preferred dissociation channel involved loss of water with methanol molecules. These results support a model employing a chain of hydrogen-bonded solvent molecules rather than one in which fused rings of ligands surround a central hydronium ion. However, CID of larger clusters, where n 2 9, showed that loss of one methanol was equal to or less than loss of water, reflecting a change in structure.