MAB ionization

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. 

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. 

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... 

The latter equation assumes a 100% linearly polarized ionizing radiation, a is the fine structure constant, Nni is the number of electrons in a nl subshell, Dni->ei l is a radial dipole photoionization amplitude, fini is the dipole photoelectron angular asymmetry parameter, and A i2 is the electric dipole-quadrupole interference term arising due to the correction term ikr in the above expression for Mab,... 

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. 

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)]. 

The corona discharge of rare-gas atoms (e.g.. He, Ne, Ar, Kr, or Xe) in a MAB gun external to the ionization chamber provides a beam of metastable atoms. The excited-state nitrogen molecnles have also been used. Because each metastable species has a different operable energy regime, a wide range of tunable excitation energy is accessible. As an example, with rare-gas atoms, the available energy... 

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... 

Rossello GAM, Rodriguez MPG, Leonardo ROD, Domingo AO, Perez MAB. Proeedure for microbial identification based on matrix-assisted laser desorption/ionization-time of flight mass spectrometry from screerring-positive urine samples. Apmis. 2014 122(9) 790-5. 

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