Neutralization-reionization mass spectrometry NRMS

Sulfurous acid has never been isolated as a pure compound, although it has recently been detected in the gas phase by neutralization reionization mass spectrometry (NRMS) following the facile dissociative ionization (70 eV) of either diethyl sulfite or ethanesulfonic acid " ... 

Neutralization-reionization mass spectrometry (NRMS) is used to generate neutral species in the gas phase that are difficult to prepare or identify by other methods. During NRMS, both cations and anions may be neutralized, generally by collision, and then reionized to confirm the stability of the neutral species. Two reviews, with particular examples in coordination chemistry, provide good information on this method and offer many examples (76,77). A good example is AuF, which has been predicted to be stable. The [AuF]+ and AuF complexes were both neutralized and reionized and the AuF species was obtained in each recovery signal. It was postulated that the elusiveness of this molecule in the condensed phases was not due to instability but rather to inter-molecular reactions (78). 

The technique of neutralization/reionization mass spectrometry (NRMS), originally introduced by McLafferty, invokes the formation of fast neutrals from a preselected ion beam, any residual ions being deflected, followed by collision-induced reionization of the neutrals and a subsequent mass spectrometric analysis16-21. 

The sites of protonation of aromatic compounds, including the possible three mono fluoronitrobenzenes, have been studied by neutralization-reionization mass spectrometry (NRMS)22. The NRMS experiments on the MD+ species generated by D2 chemical ionization clearly indicated that the D+ attachment takes place to the nitro group rather than to the aromatic ring, as evidenced by the abundant losses of OD and DNO2 (NO + OD )22. 

The dithiazolidine (44) <77CCC2672> and dioxazolidine (45) <69JOC2269> are ring systems in which the fragmentation pattern, has been used to affirm the structures. In the latter case the absence of CO2 primary loss allows differentiation from the isomeric oxadiazolidone (46) co-product. A new technique, e.g. the neutralization-reionization mass spectrometry (NRMS) in combination with... 

Schwarz and coworkers have used the technique of neutralization-reionization mass spectrometry (NRMS) to structurally characterize numerous elusive silicon-containing molecules of interstellar interest342. The identification of HNSi was supported by ab initio calculations. The radical ion [HNSi] + was produced from N2 and SiH3I in the chemical ionization source of the mass spectrometer. 

From the stable cation 9 it is possible to generate and study the elusive hydroxyacetylene (9) by neutralization-reionization mass spectrometry (NRMS). In a NRMS experiment (Scheme 13), mass-selected HC=C—OH" (keV domain) is first neutralized, e.g. by collisions with Xe any remaining ions are removed from the beam path by electrostatic... 

Over the past years a number of small silicon-containing ions have been structurally characterized by collisional-activation mass spectrometiy. These ions have been used as precursors for the generation of their neutral counterparts via Neutralization-Reionization Mass Spectrometry (NRMS) . To a large extent the interest in small elusive silicon-containing molecules is due to the role which these species have been postulated to play as intermediates and building blocks in the genesis of interstellar matter" . In particular, the different conceivable pathways which lead from atomic silicon cations to the formation of neutral silicon-containing molecules have been studied intensely" A second... 

Wesdemiotis C and McLafferty FW (1987) Neutralization-reionization mass spectrometry (NRMS). Chemical Reviews 87 485-500. 

Neutralization-reionization mass spectrometry (NRMS) is a unique mass spectral technique that allows the generation of neutral species from their charged counterparts. The major application of NRMS is to produce unstable reaction intermediates that cannot be isolated or characterized by other means to yield new, previously unknown, molecules and radicals. The method has been used successfully... 

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