title: Optimization and application of atmospheric pressure chemical and photoionization hydrogen-deuterium exchange mass spectrometry for speciation of oxygen-containing compounds.
abstract: This paper presents a detailed investigation of the feasibility of optimized positive and negative atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) and atmospheric pressure photoionization (APPI) MS coupled to hydrogen-deuterium exchange (HDX) for structural assignment of diverse oxygen-containing compounds. The important parameters for optimization of HDX MS were characterized. The optimized techniques employed in the positive and negative modes showed satisfactory HDX product ions for the model compounds when dichloromethane and toluene were employed as a co-solvent in APCI- and APPI-HDX, respectively. The evaluation of the mass spectra obtained from 38 oxygen-containing compounds demonstrated that the extent of the HDX of the ions was structure-dependent. The combination of information provided by different ionization techniques could be used for better speciation of oxygen-containing compounds. For example, (+) APPI-HDX is sensitive to compounds with alcohol, ketone, or aldehyde substituents, while (-) APPI-HDX is sensitive to compounds with carboxylic functional groups. In addition, the compounds with alcohol can be distinguished from other compounds by the presence of exchanged peaks. The combined information was applied to study chemical compositions of degraded oils. The HDX pattern, double bond equivalent (DBE) distribution, and previously reported oxidation products were combined to predict structures of the compounds produced from oxidation of oil. Overall, this study shows that APCI- and APPI-HDX MS are useful experimental techniques that can be applied for the structural analysis of oxygen-containing compounds.
authors.affiliation: Department of Chemistry, Kyungpook National University, Daegu, 702-701, Republic of Korea.
authors.forename: Thamina
authors.initials: T
authors.lastname: Acter
authors.affiliation: Department of Chemistry, Kyungpook National University, Daegu, 702-701, Republic of Korea.
authors.forename: Donghwi
authors.initials: D
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Kyungpook National University, Daegu, 702-701, Republic of Korea.
authors.forename: Arif
authors.initials: A
authors.lastname: Ahmed
authors.affiliation: Biomedical Omics Group, Korea Basic Science Institute, Cheongju, 28119, Republic of Korea.
authors.forename: Jang Mi
authors.initials: JM
authors.lastname: Jin
authors.affiliation: Oil and POPs Research Group, Korea Institute of Ocean Science and Technology, KIOST, Geoje, 656-834, Republic of Korea.
authors.forename: Un Hyuk
authors.initials: UH
authors.lastname: Yim
authors.affiliation: Oil and POPs Research Group, Korea Institute of Ocean Science and Technology, KIOST, Geoje, 656-834, Republic of Korea.
authors.forename: Won Joon
authors.initials: WJ
authors.lastname: Shim
authors.affiliation: Biomedical Omics Group, Korea Basic Science Institute, Cheongju, 28119, Republic of Korea. yhkim@kbsi.re.kr.|Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon, 305-764, Republic of Korea. yhkim@kbsi.re.kr.
authors.forename: Young Hwan
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Kyungpook National University, Daegu, 702-701, Republic of Korea. sunghwank@knu.ac.kr.|Department of Chemistry, Green Nano Center, Daegu, 702-701, Republic of Korea. sunghwank@knu.ac.kr.
authors.forename: Sunghwan
authors.initials: S
authors.lastname: Kim
keywords: Atmospheric-pressure chemical ionization; Atmospheric-pressure photoionization; Hydrogen/deuterium exchange; Mass spectrometry; Signal-to-noise ratio