Metastable atom bombardment

Principles and Characteristics In metastable atom bombardment (MAB), a metastable atom beam, generated by a gun external to the ion volume, is used to bombard the sample. MAB, based on Penning ionisation, offers unique features for gas-phase ionisation. The energy available for ionisation and fragmentation is discrete (excitation energy of the atom, from 8 to 20 eV), 

The MAB ion source offers several advantages over El for PyMS. By eliminating excessive fragmentation, characteristic of electron ionisation, and by producing highly reproducible mass spectra MAB (Kr) greatly simplifies the analysis of pyrolysis data. Furthermore, MAB ionisation, when combined to MS/MS, provides a useful tool for structural elucidation of pyrolysis products. The ability for selective ionisation can be very useful to reduce the background combination in techniques such as GC-MS, LC-MS or SFC-MS. 

Applications TPPy-MAB-MS (Ar, N2) was recently used for the analysis of bis(l,2,2,6,6-pentamethyl-4-piperidinyl) sebacate in a PUR-based car paint [71a], 

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Metastable atom bombardment. 367 6.3.6 Tandem mass spectrometry. . . 398... 

LDI Laser desorption/ionisation MAB Metastable atom bombardment... 

METHOD REPRODUCIBILITY AND SPECTRAL LIBRARY ASSEMBLY FOR RAPID BACTERIAL CHARACTERIZATION BY METASTABLE ATOM BOMBARDMENT PYROLYSIS MASS SPECTROMETRY... 

A refiectron TOF MS equipped with a metastable atom bombardment ion source. (For steps 5 and 6)... 

Metastable atom bombardment (MAB) is a novel ionization method for mass spectrometry invented by Michel Bertrand s group at the University of Montreal, Quebec, Canada, and described by Faubert et al.38 For the identification of bacteria by MS, MAB has a number of significant advantages relative to more familiar ionization techniques. Electron ionization (El) imparts so much excess energy that labile biomolecules break into very small fragments, from which the diagnostic information content is limited since all... 

Wilkes, J. G. Rushing, L. Nayak, R. Buzatu, D. A. Sutherland, J. B. Rapid phenotypic characterization of Salmonella enterica strains by pyrolysis metastable atom bombardment mass spectrometry with multivariate statistical and artificial neural network pattern recognition. J. Microbiol. Meth. submitted for publication. 

Besides El, Cl, FI or FD techniques for generating ions in the mass spectrometer, some other ionization techniques have been reported. One such technique is metastable atom bombardment (MAB), which Is based on Penning ionization. In MAB a metastable ion beam generated outside the ion volume is used to bombard the sample. The energy available for ionization is discrete (quantified) and can be fixed by the choice of the rare gas used in the atom gun (He, Ne, Ar, Kr, Xe). This energy ranges from 8 to 20 eV. 

Moore et al. (2004) reported on the use of metastable atom bombardment (MAB) ionization and HRMS in the positive ion mode for the detection of CPs [34]. Using an inert gas like argon, MAB ionization generates ions via an electrophilic reaction of a metastable atom with the analyte of interest. Figure 10 shows a comparison of ECNI and positive ion MAB mass spectra. 

Fig. 10 Mass spectra of hexachlorodecane by ECNI top panel) and metastable atom bombardment (MAB) using Ar bottom panel) [34]...

Moore S, Vromet L, Rondeau B (2004) Comparison of metastable atom bombardment and electron capture negative ionization for the analysis of polychloroaUcanes. Chemosphere 54 453 59... 

Ikonomou, M., Chromatographic and ionization properties of polybrominated diphenyl ethers using GC/high resolution MS with metastable atom bombardment and electron impact ionization. Anal. Chem., 74, 5263-5272, 2002. 

Metastable atom bombardment (MAB) is another suitable ionization option for gas-phase organic compounds [11,12]. In this approach, ionization occurs through Penning processes of the type shown in reactions (2.21) and (2.22) by bombarding the sample with a beam of metastable species. The process depicted in reaction (2.21) involves an electrophilic reaction of the metastable atom (A ) to produce an odd-electron molecular ion of the analyte. The excitation energy of A must exceed the IE of the analyte molecule. With much higher excitation energy, dissociative ionization process also takes place [reaction (2.22)]. 

Time required for extraction with SPE cartridges, chromatographic separation and LC-MS/MS determinations are too long. Therefore, a method using selective ionization of metastable atom bombardment (MAB) has been developed in order to... 

Liquid chromatography-electrospray ionization-time-of-flight-mass spectrometry. Pyrolysis-metastable atom bombardment-time-of-flight-mass spectrometry. 

Jamin, E., Chevolleau, S., Touzet, C., Tulliez, J., and Debrauwer, L. 2007. Assessment of metastable atom bombardment (MAB) ionization mass spectrometry for the fast determination of heterocyclic aromatic amines in cooked meat Anal. Bioanal. Chem. 387 2931-2941. 

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