Premium
Atmospheric pressure ionization tandem mass spectra of protonated timolol
Author(s) -
Qin XueZhi
Publication year - 1999
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(199901)34:1<51::aid-jms759>3.0.co;2-a
Subject(s) - chemistry , timolol , mass spectrometry , protonation , mass spectrum , tandem mass spectrometry , dissociation (chemistry) , amine gas treating , medicinal chemistry , photochemistry , organic chemistry , ion , chromatography , medicine , intraocular pressure , ophthalmology
Structural identification of drugs by tandem mass spectrometry(MS/MS) is interesting, important and challenging. Inthis study, atmospheric pressure ionization (API) MS/MSwas applied to probe the structure of timolol, a typicalβ‐adrenergic receptor‐blocking agent(β‐blocker). The characteristic MS/MSfeatures of this drug were analyzed in detail. The results should besignificant for other β‐blockers with similar structures(namely, the OCH 2 group sandwichedbetween the aromatic and ethanolamine groups). Furthermore,timolol is a multifunctional organic compound, containing amine,ether and alcohol functional groups. The API‐MS/MS studyis interesting from the point of view of the gas‐phasechemistry of these groups in a multifunctional compound. The resultsrevealed that under the collision‐induced dissociationconditions used for the MS/MS study, protonated timolol undergoesheterolytic, charge‐induced cleavages of the aminenitrogen–carbon and ether oxygen–carbon bonds. Themechanism of the cleavages was elucidated by comparing the tandemmass spectra of timolol with those of deuterated timolol. Thiscomparison clearly indicated that ion–neutral complexes areintermediates in the cleavages. Copyright © 1999 John Wiley& Sons, Ltd.