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Liu Y, Wang X, Zhang D, Wang C, Xie H, Chen H, Chai Y. Does deprotonated benzoic acid lose carbon monoxide in collision-induced dissociation? JOURNAL OF MASS SPECTROMETRY : JMS 2024; 59:e4990. [PMID: 38146124 DOI: 10.1002/jms.4990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 10/25/2023] [Accepted: 11/09/2023] [Indexed: 12/27/2023]
Abstract
Decarboxylation is known to be the major fragmentation pathway for the deprotonated carboxylic acids in collision-induced dissociation (CID). However, in the CID mass spectrum of deprotonated benzoic acid (m/z 121) recorded on a Q-orbitrap mass spectrometer, the dominant peak was found to be m/z 93 instead of the anticipated m/z 77. Based on theoretical calculations, 18 O-isotope labeling and MS3 experiments, we demonstrated that the fragmentation of benzoate anion begins with decarboxylation, but the initial phenide anion (m/z 77) can react with trace O2 in the mass analyzer to produce phenolate anion (m/z 93) and other oxygen-containing ions. Thus oxygen adducts should be considered when annotating the MS/MS spectra of benzoic acids.
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Affiliation(s)
- Yingying Liu
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Laboratory of Quality and Safety Risk Assessment for Tea Products (Hangzhou), Ministry of Agriculture and Rural Affairs, Hangzhou, China
- Graduate School of Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xue Wang
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Laboratory of Quality and Safety Risk Assessment for Tea Products (Hangzhou), Ministry of Agriculture and Rural Affairs, Hangzhou, China
- Graduate School of Chinese Academy of Agricultural Sciences, Beijing, China
| | - Danyang Zhang
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Laboratory of Quality and Safety Risk Assessment for Tea Products (Hangzhou), Ministry of Agriculture and Rural Affairs, Hangzhou, China
| | - Chen Wang
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Laboratory of Quality and Safety Risk Assessment for Tea Products (Hangzhou), Ministry of Agriculture and Rural Affairs, Hangzhou, China
| | - Haijiao Xie
- Hangzhou Yanqu Information Technology Co., Ltd., Hangzhou, China
| | - Hongping Chen
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Laboratory of Quality and Safety Risk Assessment for Tea Products (Hangzhou), Ministry of Agriculture and Rural Affairs, Hangzhou, China
| | - Yunfeng Chai
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Laboratory of Quality and Safety Risk Assessment for Tea Products (Hangzhou), Ministry of Agriculture and Rural Affairs, Hangzhou, China
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Ding X, Kumar M, Zheng Z, Lee A, Hopkins WS, Attygalle AB. Evidence of Gas-Phase Attachment of Molecular Oxygen to Deprotonated Hydroquinone During Ion-Mobility Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1816-1824. [PMID: 36129840 DOI: 10.1021/jasms.1c00222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Gas-phase addition of dioxygen to certain ions is a well-known phenomenon in mass spectrometry. For this reaction to occur, the presence of a distonic radical site on the precursor ion is thought to be a prerequisite. Herein, we report that oxygen adduct formation can take place also with deprotonated hydroquinone, which in fact is an even-electron species without a radical site. When the product-ion spectrum of the m/z 109 ion, generated by electrospray ionization from a solution of hydroquinone in acetonitrile, was recorded under ion-mobility conditions, a new peak was observed at m/z 141. However, an analogous peak was not visible in the spectrum acquired under nonmobility conditions (i.e., without any gas introduced to the mobility cell). Presumably, traces of oxygen present in the collision gas instigate an ion-molecule reaction to produce an adduct of m/z 141, which upon activation results in CO and H2O loss to form a product ion of m/z 95. Isotope-labeling studies confirmed that one of the hydrogen atoms from the hydroxy group and another from the aromatic ring contribute to the water loss instigated from the m/z 141 adduct. Furthermore, computational methods indicated the three-dimensional structure of the ground-state deprotonated hydroquinone to be distinctly different from those of its 1,2- and 1,3-isomers. Calculations predicted that all atoms in the two m/z 109 ions generated from catechol and resorcinol lie on one plane. In contrast, the structure of the m/z 109 ion from hydroquinone was significantly different. Computations predicted that the hydrogen atom on the intact hydroxyl group of deprotonated hydroquinone protrudes out of plane from rest of the atoms. Consequently, the exposed OH group can interact with an incoming dioxygen molecule. Computations conducted at the CAM-B3LYP/6-311++g(2d,2p) level of theory detected a minimum energy crossing point (MECP) at -4.3 kJ mol-1 below the separated O2 + deprotonated hydroquinone triplet threshold. In contrast, similar calculations conducted for catechol and resorcinol yielded MECPs of +116.9 and +69.1 kJ mol-1, respectively, above the associated triplet thresholds. These results indicated that the curve crossing required to form singlet products upon reaction with triplet O2 is favorable in the case of hydroquinone and unfavorable in the cases of catechol and resorcinol. In practical terms, the selective oxygen addition appears to be a diagnostically useful reaction to differentiate hydroquinone from its ring isomers.
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Affiliation(s)
- Xiao Ding
- Center for Mass Spectrometry, Department of Chemistry, Chemical Biology, and Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - Meenu Kumar
- Center for Mass Spectrometry, Department of Chemistry, Chemical Biology, and Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - Zhaoyu Zheng
- Center for Mass Spectrometry, Department of Chemistry, Chemical Biology, and Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - Arthur Lee
- Department of Chemistry and Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - W Scott Hopkins
- Department of Chemistry and Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Athula B Attygalle
- Center for Mass Spectrometry, Department of Chemistry, Chemical Biology, and Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
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Netting AG. The intramolecular movement of deuterium in methane electron capture negative ionization tandem mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2001; 36:222-223. [PMID: 11288206 DOI: 10.1002/jms.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Windsor ML, Zeevaart JA. Induction of ABA 8'-hydroxylase by (+)-S-, (-)-R- and 8'-8'-8'-trifluoro-S-abscisic acid in suspension cultures of potato and Arabidopsis. PHYTOCHEMISTRY 1997; 45:931-934. [PMID: 9214776 DOI: 10.1016/s0031-9422(97)00022-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Suspension cultures of potato and Arabidopsis were incubated with 50 microM of (+)-ABA and (-)-ABA for 3 hr. These pretreatments were found to increase the rate, by two- to seven-fold, of formation of [2H6] phaseic acid (PA) from [2H6] ABA, applied in a subsequent incubation. Pretreatment with trifluoro-ABA had a higher efficacy, increasing the rate of conversion 15-fold. Suspension cell cultures that had been dehydrated and then rehydrated in the presence of [2H6] ABA displayed a much lower enhancement of PA formation. We conclude that ABA induces its own oxidative catabolism in suspension cultures.
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Affiliation(s)
- M L Windsor
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing 48824, USA
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Reactive collisions in quadrupole cells 5. Reactions of singly charged transition metal ions with cyclopentene. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/0168-1176(95)04189-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Heath TG, Allison J, Watson JT. Selective detection of the tolyl cation among other [C7H 7] (+) isomers by ion/molecule reaction with dimethyl ether. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 1991; 2:270-277. [PMID: 24242346 DOI: 10.1016/1044-0305(91)80018-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/1990] [Accepted: 12/19/1990] [Indexed: 06/02/2023]
Abstract
The ion/molecule reaction of the tolyl cation with dimethyl ether has been investigated using triple quadrupole mass spectrometry. Three isomers with [C7H7](+) composition, the 3-tolyl, benzyl, and tropylium cations, were individually selected and reacted with dimethyl ether at a pressure of 1 mtorr in the second quadrupole (Q2) collision cell. Only the tolyl ion reacted to yield a methoxylated product ion peak at m/z 122. This reaction product having m/z 122 is postulated to be identical in structure with the molecular ion of 3-methyl anisole, as supported by thermochemical data and the similarity of the collision induced dissociation (CID) daughter ion mass spectra of the product ion and the molecular ion of authentic 3-methyl anisole. The daughter ion mass spectra of the three [C7H7](+) isomers during CID, by using a triple quadrupole mass spectrometer, are nearly identical; on the other hand, the analytical approach based on the ion/molecule reaction with dimethyl ether clearly exhibits distinct gas-phase chemistry reflecting structural differences among the isomers. Sot.
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Affiliation(s)
- T G Heath
- Department of Biochemistry, Biochemistry Building, Michigan State University, 48824, East Lansing, MI
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