Matrix-assisted filament desorption/ionization mass spectrometry

Karbach, Volker; Knochenmuss, Richard; Zenobi, Renato

doi:10.1016/s1044-0305(98)00099-3

Cited by 7 publications

(4 citation statements)

References 24 publications

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“…The results presented show that high temperatures are preserved on the scale of microseconds after the laser shot. Karbach et al already reported the capability of fast heating for ion desorption/ionization 11. Another phenomenon could also account for this component, involving electron bombardment of the target.…”

Section: Discussionmentioning

confidence: 99%

Delayed extraction experiments using a repulsing potential before ion extraction: evidence of non‐covalent clusters as ion precursor in UV matrix‐assisted laser desorption/ionization. Part II—Dynamic effects with α‐cyano‐4‐hydroxycinnamic acid matrix

et al. 2004

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Delayed extraction experiments were undertaken to gain a better insight into the dynamic effects involved in the ion formation in UV matrix-assisted laser desorption/ionization. Part I1 was devoted to a 2,5-dihydroxybenzoic (2,5-DHB) matrix. The results clearly demonstrated the existence and the role of high-mass precursors corresponding to a non-covalent matrix-analyte association in ion formation. In this complementary study, ion flight time and abundance were studied as a function of the delay extraction time using the matrix alpha-cyano-4-hydroxycinnamic acid (HCCA). Under our instrumental conditions, where ejected ions experienced a low repulsing electric field before extraction, two main results were obtained: (i) two ion components are observed in the peak profiles depending on the repulsing field, a first, major component (I) similar to that observed for 2,5-DHB and a second, minor component (II) apparently triggered by the delayed extraction pulse, and (ii) ion time-of-flight variation vs delay time remained lower than that noted with 2,5-DHB matrix, indicating that the initial axial velocity is smaller. The initial kinetic energy of matrix and low molecular mass peptide ions for the component I is not high enough to overcome the repulsing potential in the delay time range (200-2200 ns) and we have to assume that ions have non-covalent clusters as precursors. Complete desolvation of these clusters-aggregates would be achieved through the extraction step. Simulations of the ion time-of-flight as a function of the delay time allow the determination of the average size of the precursors, typically 4500, 40000 and 50000 u for HCCA, ACTH 7-38 and bovine insulin quasi-molecular ion, respectively, assuming that the precursors are singly charged. The size of these ion precursors is greater than that of those generated for 2,5-DHB. For component II, ions are probably not solvated and they are directly desorbed from the target. Taking into account the results on HCCA and 2,5-DHB matrices and other results from the literature, a general model for ion formation based on clusters as ion precursors is proposed and discussed.

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Section: Discussionmentioning

confidence: 99%

Delayed extraction experiments using a repulsing potential before ion extraction: evidence of non‐covalent clusters as ion precursor in UV matrix‐assisted laser desorption/ionization. Part II—Dynamic effects with α‐cyano‐4‐hydroxycinnamic acid matrix

et al. 2004

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“…Several mechanisms have been proposed to explain the ionization processes that occur in MALDI analyses. The most popular mechanisms proposed to date involve excited-state acid−base chemistry, proton transfer following matrix photoionization, hydrogen atom transfer following analyte photoionization, excited-state salt chemistry, protonation of the sodium salt of the analyte, energy pooling, and gas-phase capture of a cation by the analyte. , …”

Section: Introductionmentioning

confidence: 99%

“…These ion formation mechanisms can be divided into two categories, ion formation in the condensed phase followed by laser ablation and ion formation in the gas phase after laser ablation. Other experiments suggest that some ions may be formed as a natural consequence of the solid-to-gas-phase transition . Ionization mechanisms involving matrix radical cation formation have also been proposed. , Ion formation in the condensed phase (i.e., within the sample matrix) can be accurately predicted only on the basis of condensed-phase thermodynamics where many intermolecular interactions influence the binding.…”

Section: Introductionmentioning

confidence: 99%

Potassium Cation Affinities of Matrix Assisted Laser Desorption Ionization Matrices Determined by Threshold Collision-Induced Dissociation: Application to Benzoic Acid Derivatives

Chinthaka

Rodgers

2007

J. Phys. Chem. A

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Threshold collision-induced dissociation of K+(xBA) complexes with xenon is studied using guided ion beam mass spectrometry. The xBA ligands studied include benzoic acid and all of the mono- and dihydroxy-substituted benzoic acids: 2-, 3-, and 4-hydroxybenzoic acid and 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, and 3,5-dihydroxybenzoic acid. In all cases, the primary product corresponds to endothermic loss of the intact xBA ligand. The cross section thresholds are interpreted to yield 0 and 298 K bond dissociation energies (BDEs) for K+-xBA after accounting for the effects of multiple ion-neutral collisions, the kinetic and internal energy distributions of the reactants, and dissociation lifetimes. Density functional theory calculations at the B3LYP/6-31G* level of theory are used to determine the structures of the xBA ligands and their complexes with K+. Theoretical BDEs are determined from single-point energy calculations at the B3LYP/6-311+G(2d,2p) and MP2(full)/6-311+G(2d,2p) levels using B3LYP/6-31G* optimized geometries. Four favorable binding modes for the K+(xBA) complexes are found. In all complexes to an xBA ligand that does not have a 2-hydroxyl substituent, the most favorable binding mode corresponds to a single interaction with the carbonyl oxygen atom. Formation of a 4-membered ring via chelation interactions with both oxygen atoms of the carboxylic acid group is found to be the most favorable binding mode for all of the 2-hydroxy-substituted systems except K+(2,3-dihydroxybenzoic acid). In these complexes, a hydrogen-bonding interaction between the hydrogen atom of the carboxylic acid moiety and the oxygen atom of the 2-hydroxy substituent provides additional stabilization. Formation of a 5-membered chelation ring via interaction of K+ with the oxygen atoms of adjacent hydroxyl substituents is also favorable and corresponds to the ground-state geometry for the K+(23DHBA) complex. Formation of a 6-membered chelation ring via interaction of K+ with the carbonyl and 2-hydroxyl oxygen atoms is also quite favorable but does not correspond to the ground-state geometry for any of the systems examined here. The experimental BDEs determined here are in very good agreement with the calculated values.

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“…For example, atmospheric pressure MALDI coupling [144][145][146] may greatly simplify liquid phase coupling. Similarly, new ionization techniques, such as surface assisted laser desorption/ionization [147][148][149][150] or rapid thermal desorption [151] might extend the mass range and allow analysis of low mass compounds, currently a difficult task. Interfacing is at its beginning and exciting new developments, especially in biological mass spectrometry will be witnessed in the coming years.…”

Section: Resultsmentioning

confidence: 99%

Liquid phase interfacing and miniaturization in matrix-assisted laser desorption/ionization mass spectrometry

Foret

Preisler

2002

Proteomics

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Matrix-assisted filament desorption/ionization mass spectrometry

Cited by 7 publications

References 24 publications

Delayed extraction experiments using a repulsing potential before ion extraction: evidence of non‐covalent clusters as ion precursor in UV matrix‐assisted laser desorption/ionization. Part II—Dynamic effects with α‐cyano‐4‐hydroxycinnamic acid matrix

Delayed extraction experiments using a repulsing potential before ion extraction: evidence of non‐covalent clusters as ion precursor in UV matrix‐assisted laser desorption/ionization. Part II—Dynamic effects with α‐cyano‐4‐hydroxycinnamic acid matrix

Potassium Cation Affinities of Matrix Assisted Laser Desorption Ionization Matrices Determined by Threshold Collision-Induced Dissociation: Application to Benzoic Acid Derivatives

Liquid phase interfacing and miniaturization in matrix-assisted laser desorption/ionization mass spectrometry

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