Thermochemical determinations by the kinetic method

Cooks, R. Graham; Patrick, Jeffrey S.; Kotiaho, Tapio; McLuckey, Scott A.

doi:10.1002/mas.1280130402

Cited by 476 publications

(34 citation statements)

References 149 publications

(69 reference statements)

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“…[9,23,24,26] Thus, an affinity scale based on Equation (8) corresponds to aG ibbs energy ladder under the assumption of constant T eff .T he implications of this approximation have been widely discussed. [20][21][22][23][24] …”

Section: Scheme1mentioning

confidence: 98%

“…When low-volatility compounds are involved, av iable alternative is provided by Cooks' kinetic method. [20][21][22][23][24] This procedure relies on the assumption that the relative mass spectrometric abundanceso ft wo different ions obtained by competitive dissociation of an ion-bound cluster, reflect their relative binding strengths to acommon species: the higherthe relative abundance,t he lower the binding strength. Thus, the difference in the affinities of two dissimilar cations, C + and C' + ,f or ag iven anion,A À ,c an, for example, be determined from the ratio of their abundances upon competitive fragmentation of a[ CAC'] + speciesaccording to Scheme 1.…”

Section: Introductionmentioning

confidence: 99%

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Gas‐Phase Affinity Scales for Typical Ionic Liquid Moieties Determined by using Cooks’ Kinetic Method

2015

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Gas-phase affinity studies based on cations and anions commonly present in ionic liquid structures, give quantitative information about the magnitude of the interactions holding the two species together when ILs are formed. They also provide clues on how these interactions depend on the nature of the cationic and anionic moieties. In the present work, mass spectrometric experiments, performed using electrospray ionization quadrupole ion-trap and Fourier transform ion cyclotron resonance mass spectrometry, were used to obtain two affinity scales by Cooks' kinetic method: one scale for the various cations for the bis(trifluoromethylsulfonyl)imide anion, [NTf2 ](-) , and another for the different anions for the 1-butyl-3-methylimidazolium cation, [C4 mim](+) . The obtained results are compared with previously reported data and discussed in terms of the structural characteristics of the different cationic and anionic species.

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Section: Scheme1mentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Gas‐Phase Affinity Scales for Typical Ionic Liquid Moieties Determined by using Cooks’ Kinetic Method

2015

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“…The extended kinetic method (EKM) [6][7][8][9][10][11][12][13][14] is an improved version of the simple Cooks kinetic method [17][18][19][20] which takes into account entropic effects on the competitive dissociations of a massselected proton-bound heterodimer (cluster-) anions [A·H·Aref(i)]…”

Section: Extended Kinetic Methods (Ekm)mentioning

confidence: 99%

Intrinsic (gas-phase) acidity and basicity of paracetamol

Dávalos¹,

González²,

Ramos³

et al. 2013

Arkivoc

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Gas phase protonation enthalpy (proton affinity) and deprotonation enthalpy of paracetamol, PA = 909.4 ± 8.4 kJmol -1 and ∆acidH 0 = 1430.3 ± 8.8 kJmol -1 , have been experimentally determined by the extended kinetic method (EKM) using ESI-triple-quadrupole mass spectrometry. Gas phase basicity and acidity deduced from these experiments, GB = 869.9 ± 8.4 kJmol -1 and GA = 1404.7 ± 8.8 kJmol -1 are in good agreement with calculations performed at the B3LYP level of theory with 6-311++G(3df,2p) and 6-311++G(d,p) basis sets. We also have derived the enthalpy of formation of deprotonated (ΔfH 0 (g) = -386.4 ± 9.0 kJ·mol -1 ) and protonated (ΔfH 0 (g) = 346.3 ± 8.6 kJ·mol -1 ) paracetamol ions.

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“…A particular type of ionic cluster is the proton-bound dimer (PBD), which consists of the same (=homodimer) or different (=heterodimer) species (ions or neutrals). Their weak hydrogen bonding was used as principle of the kinetic method , which was developed by Cook and coworkers [ 45 – 47 ] and later refined, e.g., by the Fenselau group [ 48 , 49 ]. In this method, ESI combined with CID of m/z -selected PBD is used to determine relative proton affinities (PA) of ions contributing to the isolated cluster.…”

Section: Introductionmentioning

confidence: 99%

MALDI Mass Spectral Imaging of Bile Acids Observed as Deprotonated Molecules and Proton-Bound Dimers from Mouse Liver Sections

Rzagalinski

Hainz

Meier

et al. 2018

J. Am. Soc. Mass Spectrom.

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Bile acids (BAs) play two vital roles in living organisms, as they are involved in (1) the secretion of cholesterol from liver, and (2) the lipid digestion/absorption in the intestine. Abnormal bile acid synthesis or secretion can lead to severe liver disorders. Even though there is extensive literature on the mass spectrometric determination of BAs in biofluids and tissue homogenates, there are no reports on the spatial distribution in the biliary network of the liver. Here, we demonstrate the application of high mass resolution/mass accuracy matrix-assisted laser desorption/ionization (MALDI)-Fourier-transform ion cyclotron resonance (FTICR) to MS imaging (MSI) of BAs at high spatial resolutions (pixel size, 25 μm). The results show chemical heterogeneity of the mouse liver sections with a number of branching biliary and blood ducts. In addition to ion signals from deprotonation of the BA molecules, MALDI-MSI generated several further intense signals at larger m/z for the BAs. These signals were spatially co-localized with the deprotonated molecules and easily misinterpreted as additional products of BA biotransformations. In-depth analysis of accurate mass shifts and additional electrospray ionization and MALDI-FTICR experiments, however, confirmed them as proton-bound dimers. Interestingly, dimers of bile acids, but also unusual mixed dimers of different taurine-conjugated bile acids and free taurine, were identified. Since formation of these complexes will negatively influence signal intensities of the desired [M – H]- ions and significantly complicate mass spectral interpretations, two simple broadband techniques were proposed for non-selective dissociation of dimers that lead to increased signals for the deprotonated BAs. Graphical Abstractᅟ Electronic supplementary materialThe online version of this article (10.1007/s13361-017-1886-6) contains supplementary material, which is available to authorized users.

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Thermochemical determinations by the kinetic method

Cited by 476 publications

References 149 publications

Gas‐Phase Affinity Scales for Typical Ionic Liquid Moieties Determined by using Cooks’ Kinetic Method

Gas‐Phase Affinity Scales for Typical Ionic Liquid Moieties Determined by using Cooks’ Kinetic Method

Intrinsic (gas-phase) acidity and basicity of paracetamol

MALDI Mass Spectral Imaging of Bile Acids Observed as Deprotonated Molecules and Proton-Bound Dimers from Mouse Liver Sections

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