Hydrodynamic model of matrix-assisted laser desorption mass spectrometry

Vertes, Akos; Irinyi, Gyorgy.; Gijbels, R.

doi:10.1021/ac00065a036

Cited by 110 publications

(94 citation statements)

References 8 publications

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“…Time-resolved spectroscopy and imaging methods have been also employed to study the dynamics of material disintegration and the ablation plume expansion. [40][41][42] The growing experimental effort has been supported by theoretical studies, 3,[43][44][45][46][47] numerical analysis of kinetic models, [48][49][50][51][52][53] and molecular dynamics (MD) simulations of laser desorption/ablation. The diversity and complexity of the intertwined processes involved in laser ablation and occurring at different time and length scales present a challenge for theoretical and computational descriptions of this phenomenon.…”

Section: Introductionmentioning

confidence: 99%

Computer Simulations of Laser Ablation of Molecular Substrates

Zhigilei

Leveugle

Garrison³

et al. 2003

Chem. Rev.

281

248

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Section: Introductionmentioning

confidence: 99%

Computer Simulations of Laser Ablation of Molecular Substrates

Zhigilei

Leveugle

Garrison³

et al. 2003

Chem. Rev.

281

248

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“…In addition to application issues, the study of the matrix influence on analyte fragmentation can also bring new elements to the picture of the MALDI mechanism. Several groups have therefore put some effort into the experimental characterization of ion internal energy in MALDI [8 -14], or to elaborate MALDI models taking ion internal energy or plume temperature into account [15][16][17][18][19][20]. Analyte internal energy can be modified by collisional heating and by electronic or vibrational energy-transfer from the matrix, and the study of analyte fragmentation will hopefully bring complementary information on these processes.…”

mentioning

confidence: 99%

Influence of the matrix on analyte fragmentation in atmospheric pressure MALDI

Schulz

Karas

Rosu

et al. 2006

J. Am. Soc. Mass Spectrom.

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In this paper, we report the measurement of the degree of analyte fragmentation in AP-MALDI as a function of the matrix and of the laser fluence. The analytes include p-OCH 3 -benzylpyridinium, three peptides containing the sequence EEPP (which cleave very efficiently at the E-P site), and three deoxynucleosides (dA, dG, and dC), which lose the neutral sugar to give the protonated base. We found that the matrix hardness/softness was consistent when comparing the analytes, with a consensus ranking from hardest to softest: CHCA Ͼ Ͼ DHB Ͼ SA Ϸ THAP Ͼ ATT Ͼ HPA. However, the exact ranking can be fluence-dependent, for example between ATT and HPA. Our goal here was to provide the scientific community with a detailed dataset that can be used to compare with theoretical predictions. We tried to correlate the consensus ranking with different matrix properties: sublimation or decomposition temperature (determined using thermogravimetry), analyte initial velocity, and matrix proton affinity. The best correlation was found with the matrix proton affinity. T he most exciting innovations in the last 15 years for the analysis of nonvolatile, high molecular weight compounds like peptides, proteins, oligonucleotides, carbohydrates, and synthetic polymers came from the development of two new ionization techniques for mass spectrometry: matrix-assisted laser desorption/ionization (MALDI) [1,2] and electrospray ionization (ESI) [3]. MALDI has established itself as a powerful analytical technique. However, despite its wide range of applications and many fundamental studies (for review articles, see [4 -7]), there is still a need for better understanding of the MALDI process, to improve ion yields, and to provide rational guidelines for matrix selection. The currently most widely used matrices were found empirically. An important step in the research for new (tailor-made) matrices is an improved knowledge of the role of the matrix in MALDI, and the establishment of criteria to predict matrix properties. The role of the matrix is 3-fold. (1) The matrix has to absorb the laser energy (via electronic excitation in case of UV-MALDI or vibrational excitation in case of IR-MALDI). (2) Disintegration of the condensed phase has to take place without excessive destructive heating of the embedded analyte molecules. (3) An efficient ionization of the analyte molecules has to be provided.It is well known experimentally that MALDI matrices can cause more or less analyte fragmentation, and matrices are therefore characterized as "hard" or "soft", respectively. While ionization with minimal internal energy deposition ("softness") is required for molecular mass determination, extensive fragmentation ("hardness") is advantageous for structural studies, and particularly for peptide sequencing. In addition to application issues, the study of the matrix influence on analyte fragmentation can also bring new elements to the picture of the MALDI mechanism. Several groups have therefore put some effort into the experimental characterization of ion internal...

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“…At short extraction delays, the ions may have not reached their "final" initial velocity and collisions with neutrals can slow ions down. The time lag, until a free expansion regime can be considered, has been estimated from hydrodynamic calculations to be about 50-100 ns [14]. Therefore, the time lag also depends on the laser irradiance due to the substantial interaction between ions and neutrals.…”

Section: Theorymentioning

confidence: 99%

Mechanism of insulin emission in matrix assisted laser ionization

Fernandez‐Lima¹,

Collado²,

Ponciano³

et al. 2005

Braz. J. Phys.

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In the present paper the emission of intact insulin quasi-molecular ion [M+H] + during laser ablation (MALDI) is studied. It was observed in particular that the insulin TOF molecular peak increases as the laser power increases. The DE-Vestal method for the initial velocity measurements was improved theoretically including the distance (d0) until the free expansion regime can be considered. According to the present analysis, the v0 parameter given by the DE-Vestal method is interpreted as the initial velocity that the desorbed ion would have if no collision occurs in the plasma. The improved method interprets v 0 as the "final" initial velocity, i.e., as the velocity that the desorbed ions have when the plasma free expansion starts and, effectively, collisions no longer occur. The new method allows also the determination of d 0 , the distance to the solid when the free expansion starts. The data fitting shows that the distance (d0) has a linear dependence on the laser's intensity. Extrapolation of these values gives I = 0.69 G W cm −2 as the minimum energy density necessary to produce high density plasma during the insulin ions desorption when using αCHCA matrix.

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Hydrodynamic model of matrix-assisted laser desorption mass spectrometry

Cited by 110 publications

References 8 publications

Computer Simulations of Laser Ablation of Molecular Substrates

Computer Simulations of Laser Ablation of Molecular Substrates

Influence of the matrix on analyte fragmentation in atmospheric pressure MALDI

Mechanism of insulin emission in matrix assisted laser ionization

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