Temperature dependence of dissociative electron attachment to molecules of gentisic acid, hydroquinone and p-benzoquinone

Pshenichnyuk, S. A.; Asfandiarov, N. L.; Fal’ko, Vladimir I.; Lukin, V. G.

doi:10.1016/s1387-3806(03)00168-4

Cited by 22 publications

(24 citation statements)

References 12 publications

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“…A pooling ionization event yields a matrix cation and a free electron. The electron is propagated in a random direction, to be captured by neutral molecules at a rate determined by the cross section 26–29. The mean free path in the solid matrix is thus on the order of 10 nm.…”

Section: Methodsmentioning

confidence: 99%

Molecular dynamics simulations of MALDI: laser fluence and pulse width dependence of plume characteristics and consequences for matrix and analyte ionization

Knochenmuss

Zhigilei

2010

J. Mass Spectrom.

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Molecular dynamics simulations of matrix-assisted laser desorption/ionization were carried out to investigate laser pulse width and fluence effects on primary and secondary ionization process. At the same fluence, short (35 or 350 ps) pulses lead to much higher initial pressures and ion concentrations than longer ones (3 ns), but these differences do not persist because the system relaxes toward local thermal equilibrium on a nanosecond timescale. Higher fluences accentuate the initial disparities, but downstream differences are not substantial. Axial velocities of ions and neutrals are found to span a wide range, and be fluence dependent. Total ion yield is only weakly dependent on pulse width, and consistent with experimental estimates. Secondary reactions of matrix cations with analyte neutrals are efficient even though analyte ions are ablated in clusters of matrix.

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Section: Methodsmentioning

confidence: 99%

Molecular dynamics simulations of MALDI: laser fluence and pulse width dependence of plume characteristics and consequences for matrix and analyte ionization

Knochenmuss

Zhigilei

2010

J. Mass Spectrom.

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“…Thus, it is proposed that the Oanion in ECNI mass spectra of α-cyano-4-hydroxicynnamic acid is attributed to the carbon dioxide molecule. As depicted earlier, 40 molecules of carboxylic acids undergo decarboxylation in the collision chamber of the mass spectrometer, which is the origin of the CO 2 molecules. In the work by Spence et al, 48 it was pointed out that, in the range of temperatures from 300 K to 550 K, there are no temperature effects in the yield of Ofrom the parent anion of carbon dioxide.…”

Section: Resultsmentioning

confidence: 83%

“…A role of electron attachment in conventional MALDI experiments may be defined more precisely by means of a simple comparison between ECNI mass spectra and negative-mode MALDI mass spectra of the matrix substance only, with no analyte molecules incorporated. In our recent works, 37,40 the data on low-energy electron capture by molecules of typical MALDI matrices were presented. Unfortunately, to the best of our knowledge, there are no corresponding results on negative-mode MALDI of pure matrix substances to carry out the comparison needed, with the exception of the work carried out by Bourcier et al, 36 which will probably confirm our assumption on the role of free electrons in MALDI.…”

Section: Sa Pshenichnyuk * and Nl Asfandiarovmentioning

confidence: 99%

“…This substance was not investigated in our latest works. 37,40 Presented experimental results also include the temperature dependence of the electron capture process. The temperature in MALDI was estimated to vary from ambient temperature (before applying the laser pulse) to approximately 500-700 K (after applying the laser pulse), in the MALDI plume.…”

Section: Sa Pshenichnyuk * and Nl Asfandiarovmentioning

confidence: 99%

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The Role of Free Electrons in Matrix-Assisted Laser Desorption/Ionization: Electron Capture by Molecules of α-Cyano-4-Hydroxycinnamic Acid

Pshenichnyuk

Asfandiarov

2004

Eur J Mass Spectrom (Chichester)

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Low-energy (0-12 eV) electron attachment to molecules of a typical matrix substance used for matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS), namely alpha-cyano-4-hydroxicynnamic acid, has been investigated in the gas phase at different temperatures ranging from 140 degrees C to 260 degrees C by means of electron capture negative-ion mass spectrometry (ECNI MS). The yield of negative ions, formed by electron capture, was measured as a function of incident electron energy for four different temperatures. The long-lived parent molecular anion, [M]- (m/z 189), was observed in the negative-ion mass spectra of the substance under investigation. Its autodetachment lifetime was estimated to be approximately 600 micros. It was found that at 140 degrees C the main decay channel of the long-lived temporary molecular anion of alpha-cyano-4-hydroxicynnamic acid is a formation of the [M-COOH]-; fragment negative ion (m/z 144) with an intensity of 37.2% in percentage terms in respect of the total anion current. There are also [M-H]-, [M-CO2]- and [CN]- fragments in the spectra with intensities of about 7.7%, 21.6% and 3.1% at 140 degrees C. It was shown that the escape of the CO2 molecule from the parent molecular anion is a slow process. It takes [M]- about 10 micros to decay on carbon dioxide molecules and [M-CO2]- fragment anions. Increasing the temperature of the target molecule alters the negative-ion mass spectra of alpha-cyano-4-hydroxicynnamic acid significantly. A possible role for the findings in typical MALDI MS experiments is discussed.

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“…By comparing the peak positions in the anion efficiency curves for the dehydrogenation of both CoQ 0 (obtained here) and p ‐BQ, [50] it can be derived that the dehydrogenation of both quinone analogues occurs at similar electron energies close to 1.8 and 7.0 eV while the core‐excited resonance at 4.86 eV is absent in CoQ 0 . In DEA studies to HQ, Pshenichnyuk et al [63] . reported the formation of the dehydrogenated molecular anion of HQ at 1.6 eV as the most intense dissociation pathway, in addition to a weaker contribution at 4.2 eV.…”

Section: Resultsmentioning

confidence: 99%

Formation of Temporary Negative Ions and Their Subsequent Fragmentation upon Electron Attachment to CoQ₀ and CoQ₀H₂

et al. 2022

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Ubiquinone molecules have a high biological relevance due to their action as electron carriers in the mitochondrial electron transport chain. Here, we studied the dissociative interaction of free electrons with CoQ0, the smallest ubiquinone derivative with no isoprenyl units, and its fully reduced form, 2,3‐dimethoxy‐5‐methylhydroquinone (CoQ0H2), an ubiquinol derivative. The anionic products produced upon dissociative electron attachment (DEA) were detected by quadrupole mass spectrometry and studied theoretically through quantum chemical and electron scattering calculations. Despite the structural similarity of the two studied molecules, remarkably only a few DEA reactions are present for both compounds, such as abstraction of a neutral hydrogen atom or the release of a negatively charged methyl group. While the loss of a neutral methyl group represents the most abundant reaction observed in DEA to CoQ0, this pathway is not observed for CoQ0H2. Instead, the loss of a neutral OH radical from the CoQ0H2 temporary negative ion is observed as the most abundant reaction channel. Overall, this study gives insights into electron attachment properties of simple derivatives of more complex molecules found in biochemical pathways.

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Temperature dependence of dissociative electron attachment to molecules of gentisic acid, hydroquinone and p-benzoquinone

Cited by 22 publications

References 12 publications

Molecular dynamics simulations of MALDI: laser fluence and pulse width dependence of plume characteristics and consequences for matrix and analyte ionization

Molecular dynamics simulations of MALDI: laser fluence and pulse width dependence of plume characteristics and consequences for matrix and analyte ionization

The Role of Free Electrons in Matrix-Assisted Laser Desorption/Ionization: Electron Capture by Molecules of α-Cyano-4-Hydroxycinnamic Acid

Formation of Temporary Negative Ions and Their Subsequent Fragmentation upon Electron Attachment to CoQ₀ and CoQ₀H₂

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Temperature dependence of dissociative electron attachment to molecules of gentisic acid, hydroquinone and p-benzoquinone

Cited by 22 publications

References 12 publications

Molecular dynamics simulations of MALDI: laser fluence and pulse width dependence of plume characteristics and consequences for matrix and analyte ionization

Molecular dynamics simulations of MALDI: laser fluence and pulse width dependence of plume characteristics and consequences for matrix and analyte ionization

The Role of Free Electrons in Matrix-Assisted Laser Desorption/Ionization: Electron Capture by Molecules of α-Cyano-4-Hydroxycinnamic Acid

Formation of Temporary Negative Ions and Their Subsequent Fragmentation upon Electron Attachment to CoQ0 and CoQ0H2

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Formation of Temporary Negative Ions and Their Subsequent Fragmentation upon Electron Attachment to CoQ₀ and CoQ₀H₂