Collision-Induced Desorption

When adsorbed molecules are bombarded with electrons, local heating effects occur that lead to thermal desorption. In addition, there is a small but finite probability that electrons in the chemical bonds that hold the adsorbate to the surface will be excited into a repulsive state, leading to the desorption of that molecule either as a neutral species or as a molecular ion. Desorption of neutral species under electron-beam bombardment is frequently observed in studies of electron-surface interactions. A fraction of the adsorbed molecules will be ionized. These can be detected as positive ions, and the spatial distribution of this ion flux can be imaged on a fluorescent screen. Electron-stimulated desorption ion-angular distribution (ESDIAD) [56, 61, 64, 79-84] is the name of the technique that is used to learn about the site symmetry and orientation of adsorbed molecular species, since the molecular ions are usually emitted in the directions of their chemical bonds with the surface and with an unchanged orientation with respect to the orientation of the molecule when it was adsorbed on the surface. 

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Shimokawa, S., Namiki, A., Garno, M. N. and Ando, T. Temperature dependence of atomic hydrogen-induced surface processes on Ge(100) Thermal desorption, abstraction, and collision-induced desorption. Journal of Chemical Physics 113, 6916-25 (2000). 

We have observed another collision induced process, the collision induced desorption of molecular methane (ref. 9). The simultaneous occurrence of this process, which is roughly an order of magnitude more probable than dissociation, necessitates that the flux of methane incident on the surface... 

Experiments of thermal desorption and collision-induced desorption showed that gold particles (2-5 nm) supported on TiO2(110), and populated with both Ojds and 02,ads produces more CO2 than the sample populated with Ojds alone. This was interpreted as evidence that molecularly chemisorbed oxygen directly participates in the CO oxidahon reaction, and that the reaction pathway does not require the dissociation of oxygen [172]. 

M)MB (laser-induced, collision-induced) desorption (Modulated) molecular beam Yes243.244 No... 

S.T. Hsiao, M.C. Tseng, Y.R. Chen and G.R. Her, Analysis of polymer additives by matrix-assisted laser desorption ionisation/time of flight mass spectrometer using delayed extraction and collision induced dissociation, J. Chinese Chem. Soc., 48 (2001) 1017-1027. 

DGE a AC AMS APCI API AP-MALDI APPI ASAP BIRD c CAD CE CF CF-FAB Cl CID cw CZE Da DAPCI DART DC DE DESI DIOS DTIMS EC ECD El ELDI EM ESI ETD eV f FAB FAIMS FD FI FT FTICR two-dimensional gel electrophoresis atto, 10 18 alternating current accelerator mass spectrometry atmospheric pressure chemical ionization atmospheric pressure ionization atmospheric pressure matrix-assisted laser desorption/ionization atmospheric pressure photoionization atmospheric-pressure solids analysis probe blackbody infrared radiative dissociation centi, 10-2 collision-activated dissociation capillary electrophoresis continuous flow continuous flow fast atom bombardment chemical ionization collision-induced dissociation continuous wave capillary zone electrophoresis dalton desorption atmospheric pressure chemical ionization direct analysis in real time direct current delayed extraction desorption electrospray ionization desorption/ionization on silicon drift tube ion mobility spectrometry electrochromatography electron capture dissociation electron ionization electrospray-assisted laser desorption/ionization electron multiplier electrospray ionization electron transfer dissociation electron volt femto, 1CT15 fast atom bombardment field asymmetric waveform ion mobility spectrometry field desorption field ionization Fourier transform Fourier transform ion cyclotron resonance... 

FAB and LSIMS are matrix-mediated desorption techniques that use energetic particle bombardment to simultaneously ionize samples like carotenoids and transfer them to the gas phase for mass spectrometric analysis. Molecular ions and/or protonated molecules are usually abundant and fragmentation is minimal. Tandem mass spectrometry with collision-induced dissociation (CID) may be used to produce abundant structurally significant fragment ions from molecular ion precursors (formed using FAB or any suitable ionization technique) for additional characterization and identification of chlorophylls and their derivatives. Continuous-flow FAB/LSIMS may be interfaced to an HPLC system for high-throughput flow-injection analysis or on-line LC/MS. 

The fast desorption of CO in CO/Cu(OOf) has been measured [33] and also calculated. [30,31] The collision induced vibrational excitation and following relaxation of CO on Cu(001) has also been experimentally explored using time-of-flight techniques, and has been analyzed in experiments [34] and theory. [23,32] Our previous treatment of instantaneous electronic de-excitation of CO/Cu(001) after photoexcitation is extended here to include delayed vibrational relaxation of CO/Cu(001) in its ground electronic state. We show results for the density matrix, from calculations with the described numerical procedure for the integrodifferential equations. 

Key Words Antibacterial peptide collision-induced dissociation (CID) electrospray ionization (ESI) matrix-assisted laser desorption/ionization (MALDI) peptide derivati-zation. 

Desorption chemical ionization (DCI) mass spectrum of natural cocoa butter and collision-induced dissociation DCI/MS/MS traces of deprotonated molecular ions of 887 Th (A), 859 Th (B) and 831 Th (C). Reproduced (modified) from Stroobant V., Rozenberg R., Bouabsa E.M., Deffense E. and de Hoffmann E., J. Am. Soc. Mass Spectrom., 6, 498-506, 1995, with permission. 

Doroshenko, V. M., Cotter, R. ). (1995). High-performance collision-induced dissociation of peptide ions formed by matrix-assisted laser desorption/ ionization in a quadrupole ion trap mass spectrometer. Anal. Chem. SJ, 2180-2187. 

Mass spectrometry (MS) and tandem mass spectrometry (MS/MS) play an important role in the identification of unknown compounds. Different ionization techniques have been used in studying isothiazole derivatives, such as electronic ionization (El), desorption chemical ionization (DCI), fast atom bombardment (FAB), field desorption (FD), and chemical ionization (Cl). Different MS/MS experiments have been described, such as investigation of metastable and collision-induced dissociations to study isothiazoles gas-phase ion chemistry. In addition, MS and MS/MS have been used to differentiate isothiazole isomers differing in the position of endocyclic groups or exocyclic substituents <1998THS(2)471, 1999THS(3)369, 2000THS(4)405>. 

Gord JR, Bemish RJ, Freiser BS (1990) Collision-induced dissociation of positive and negative copper-oxide cluster ions generated by direct laser desorption ionization of copper-oxide. Int J Mass Spectrom Ion Processes 102 115... 

Pevsner, P.H. et al., Direct identification of proteins from T47D cells and murine brain tissue by matrix-assisted laser desorption/ionization postsource decay/collision-induced dissociation, Rapid Commun. Mass Spectrom., 21,429, 2007. 

Modem mass spectrometric methods greatly help to speed up degradation studies by identifying the molecular mass of peptide fragments. Various desorption techniques, which produce protonated protein ions in the gas phase, are applied. Prominent examples are fast-atom bombardment (FAB) and matrix- assisted laser desorption/ionization (MALDI). Most commonly these techniques provide only the mass of the molecular ion, but they can be coupled with a collision-induced dissociation (CID) procedure. The ions are activated by collisions with neutral target gases, and the peptides dissociate in the gas phase. The resulting mass spectra... 

Macht, M., Asperger, A., and Deininger, S. O. (2004) Comparison of laser-induced dissociation and high-energy collision-induced dissociation using matrix-assisted laser desorption/ionization tandem time-of-flight (MALDI-TOE/TOF) for peptide and protein identification. Rapid Commun. Mass Spectrom. 18, 2093-2105. 

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