Loss of H2O from M + t-Butyl Complex Ions of Benzyl Alcohol in Isobutane Chemical Ionization Mass Spectrometry

✍ Scribed by Joachim G. Liehr; Gareth A. Brenton; John H. Beynon; James A. McCloskey; Wolfgang Blum; Wilhelm J. Richter

• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: German
• Weight: 428 KB
• Volume: 64
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19810640322

✦ Synopsis

In isobutane chemical ionization mass spectrometry benzyl alcohol exhibits ions at m/z 147 ('M+ 39') that arise by a loss of H 2 0 from [ M + C4Hy]+, i.e. 'M+ 57' complex ions. Electrophilic aromatic substitution of a proton at an ortho-position of neutral C6H5CH20H with [t-C4Hy]+ and, alternatively, nucleophilic substitution of H 2 0 at the benzylic carbon in C6H5CH20H2 with CH2=C(CH3), are discussed as possible pathways. Evidence in favor of the latter is derived from the analysis of C6D5CH20H and C6H5CD20H for the origin of the H-atoms lost in H20. The inferred ion structure of mlz 147 is verified by mass-analyzed ion kinetic energy (MIKE.) measurements of its collision-activated (CA.) decomposition. M I K E K A . spectra of mass-selected m/z 147 ions, once generated by CI(i-C4Hlo) from benzyl alcohol and, once, from 2-methyl-4-phenyl-2-butanol match closely and, thus, reflect identical ion structures. With reference to the simple genesis of this ion from the latter precursor, the structure in question can be concluded to be C&CH$H26 (CH,),.