title: Sterically hindered phenols in negative ion mobility spectrometry-mass spectrometry.
abstract: Negative corona discharge atmospheric pressure chemical ionization (APCI) was used to investigate phenols with varying numbers of tert-butyl groups using ion mobility spectrometry-mass spectrometry (IMS-MS). The main characteristic ion observed for all the phenolic compounds was the deprotonated molecule [M-H](-). 2-tert-Butylphenol showed one main mobility peak in the mass-selected mobility spectrum of the [M-H](-) ion measured under nitrogen atmosphere. When air was used as a nebulizer gas an oxygen addition ion was seen in the mass spectrum and, interestingly, this new species [M-H+O](-) had a shorter drift time than the lighter [M-H](-) ion. Other phenolic compounds primarily produced two IMS peaks in the mass-selected mobility spectra measured using the [M-H](-) ion. It was also observed that two isomeric compounds, 2,4-di-tert-butylphenol and 2,6-di-tert-butylphenol, could be separated with IMS. In addition, mobilities of various characteristic ions of 2,4,6-trinitrotoluene were measured, since this compound was previously used as a mobility standard. The possibility of using phenolic compounds as mobility standards is also discussed.
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, P.O. Box 55, FI-00014 University of Helsinki, Finland. jaakko.laakia@helsinki.fi
authors.forename: Jaakko
authors.initials: J
authors.lastname: Laakia
authors.forename: Christian Schack
authors.initials: CS
authors.lastname: Pedersen
authors.forename: Alexey
authors.initials: A
authors.lastname: Adamov
authors.forename: Jyrki
authors.initials: J
authors.lastname: Viidanoja
authors.forename: Alexey
authors.initials: A
authors.lastname: Sysoev
authors.forename: Tapio
authors.initials: T
authors.lastname: Kotiaho
mesh_terms: D010636:Phenols / Q000737:chemistry*; D013237:Stereoisomerism; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D010636:Phenols