On the Use of the Kinetic Method for the Determination of Proton Affinities by Fourier-transform Ion Cyclotron Resonance Mass Spectrometry

Decouzon, M.; Gal, Jean Francois; Herreros, M.; Maria, Pierre‐Charles; Murrell, J.; Todd, John F. J.

doi:10.1002/(sici)1097-0231(19960131)10:2<242::aid-rcm473>3.0.co;2-6

Cited by 28 publications

(21 citation statements)

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“…This success mainly lies on the operational simplicity of the method and its adaptability to most of the commercially available tandem mass spectrometers. Accordingly, the kinetic method has been initially developed in magnetic sector and triple quadrupole tandem instruments, it has been further used in quadrupole ion trap (Nourse & Cooks, 1991) and ion cyclotron resonance (Decouzon et al, 1996) apparatus. By contrast the underlying theory of the method and the significance of the resulting data have been the subject of active discussions during the years.…”

Section: Introductionmentioning

confidence: 99%

Gas‐phase basicities of polyfunctional molecules. Part 1: Theory and methods

Bouchoux

2007

Mass Spectrometry Reviews

116

197

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The experimental and theoretical methods of determination of gas-phase basicities, proton affinities and protonation entropies are presented in a tutorial form. Particularities and limitations of these methods when applied to polyfunctional molecules are emphasized. Structural effects during the protonation process in the gas-phase and their consequences on the corresponding thermochemistry are reviewed and classified. The role of the nature of the basic site (protonation on non-bonded electron pairs or on p-electron systems) and of substituent effects (electrostatic and resonance) are first examined. Then, linear correlations observed between gas-phase basicities and ionization energies or substituent constants are recalled. Hydrogen bonding plays a special part in proton transfer reactions and in the protonation characteristics of polyfunctional molecules. A survey of the main properties of intermolecular and intramolecular hydrogen bonding in both neutral and protonated species is proposed. Consequences on the protonation thermochemistry, particularly of polyfunctional molecules are discussed. Finally, chemical reactions which may potentially occur inside protonated clusters during the measurement of gas-phase basicities or inside a protonated polyfunctional molecule is examined. Examples of bond dissociations with hydride or alkyl migrations, proton transport catalysis, tautomerization, cyclization, ring opening and nucleophilic substitution are presented to illustrate the potentially complex chemistry that may accompany the protonation of polyfunctional molecules. # 2007 Wiley Periodicals, Inc., Mass Spec Rev 26:775-835, 2007

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Section: Introductionmentioning

confidence: 99%

Gas‐phase basicities of polyfunctional molecules. Part 1: Theory and methods

Bouchoux

2007

Mass Spectrometry Reviews

116

197

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“…The low‐energy CAD spectrum shows the ‘+44’ species is not formally bonded but is rather an adduct. The relative intensity of m/z 44 to m/z 271 suggests that the 43 Da species has a higher gas‐phase basicity (GB) than that of sultam 22. Based on these experiments and accurate mass measurement data, we determined that the ‘+44’ species is protonated ethanimine, [CH 3 CHNH+H] + .…”

Section: Resultsmentioning

confidence: 99%

Acetonitrile/water gas‐phase reaction products observed by use of atmospheric pressure chemical ionization: adducts formed with sulfonamides

Ross

Coddington

Murphy

et al. 2005

Rapid Comm Mass Spectrometry

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Electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) are the two most common mass spectrometric ionization methods used in the pharmaceutical industry. However, APCI analysis can sometimes lead to ambiguity in compound characterization and quantitation due to gas-phase reactions occurring between acetonitrile and water in the plasma, and between these plasma-generated compounds and the analyte. During the analysis of various sultams and sulfonamides we observed signals corresponding to m/z [M+44](+) and [M+60](+). Various solvent conditions and collisionally activated dissociation MS(n) experiments revealed that under the high-energy plasma conditions of APCI, the acetonitrile/water solvent mixture reacts undergoing acid-catalyzed hydrolysis producing acetamide, 59 Da. Further, the highly reactive 43 Da species ethanimine is also produced. These two compounds, normally not observed in APCI analysis, are stabilized by the sulfonamide and appear as adduct species in the mass spectra. The sulfone oxygens and the lone pair of electrons on the amide nitrogen play a role in stabilizing this adduct.

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“…Critical tests for 2,3-dihydro-pyran and tetrahydropyran have been previously performed (for details see Table S7). 43,44 PA and GB were calculated using enthalpies and Gibbs energies, respectively, accordingly for reaction (1), where [M + H] + is the protonated form of neutral specie M. [40][41][42] Enthalpy and Gibbs energy of the proton were considered as 1.48 and −6.28 kcal/mol, respectively. 45 All stationary points were characterized by frequency calculations and reported energies include zero-point energy corrections for geometry optimization.…”

Section: Computational Methodologymentioning

confidence: 99%

Combined use of tandem mass spectrometry and computational chemistry to study 2H‐chromenes from Piper aduncum

et al. 2019

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Natural 2H‐chromenes were isolated from the crude extract of Piper aduncum (Piperaceae) and analyzed by electrospray ionization tandem mass spectrometry (ESI‐MS/MS) applying collision‐induced dissociation. Density functional theory (DFT) calculations were used to explain the preferred protonation sites of the 2H‐chromenes based on thermochemical parameters, including atomic charges, proton affinity, and gas‐phase basicity. After identifying the nucleophilic sites, the pathways were proposed to justify the formation of the diagnostic ions under ESI‐MS/MS conditions. The calculated relative energy for each pathway was in good agreement with the energy‐resolved plot obtained from ESI‐MS/MS data. Moreover, the 2H‐chromene underwent proton attachment on the prenyl moiety via a six‐membered transition state. This behavior resulted in the formation of a diagnostic ion due to 2‐methylpropene loss. These studies provide novel insights into gas‐phase dissociation for natural benzopyran compounds, indicating how reactivity is correlated to the intrinsic acid‐base equilibrium and structural aspects, including the substitution pattern on the aromatic moiety. Therefore, these results can be applied in the identification of benzopyran derivatives in a variety of biological samples.

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On the Use of the Kinetic Method for the Determination of Proton Affinities by Fourier-transform Ion Cyclotron Resonance Mass Spectrometry

Cited by 28 publications

References 1 publication

Gas‐phase basicities of polyfunctional molecules. Part 1: Theory and methods

Gas‐phase basicities of polyfunctional molecules. Part 1: Theory and methods

Acetonitrile/water gas‐phase reaction products observed by use of atmospheric pressure chemical ionization: adducts formed with sulfonamides

Combined use of tandem mass spectrometry and computational chemistry to study 2H‐chromenes from Piper aduncum

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