Fragmentation in mass

Metastable ions yield valuable information on fragmentation in mass spectrometry, providing insight into molecular structure. In electron ionization, metastable ions appear naturally along with the much more abundant normal ions. Abundances of metastable ions can be enhanced by collisionally induced decomposition. 

Keywords retro-Diels-Alder fragmentation occurring in gas-phase, fragmentation in mass spectrometry... 

The major fragmentation in mass spectra of 1,2,5-oxadiazoles is attributed to the loss of nitrile and nitrile oxide or expulsion of NO. The conversion of 3,4-dicyano-l,2,5-oxadiazole-2-oxide (3,4-dicyanofuroxan) 10 to cyanogen iV-oxide 11 (Equation 5) was investigated under the conditions of collisional activation (CA) and neutralization-reionization (NR) mass spectrometry. Flash vacuum thermolysis mass-spectrometry (FVT-MS) and flash vacuum thermolysis infra-red (FVT-IR) investigations of furoxans 10, 12, and 13 reveal that small amounts of cyano isocyanate accompany the formation of the main thermolysis product 11 <2000J(P2)473>. 

Pyrolysis Process Compared to Ion Fragmentation in Mass Spectrometry. 

Many fragmentations in mass spectrometry proceed so as to form a stable carbo-cation, and the principles that we have developed regarding carbocation stability apply. 

Fragmentation in mass spectrometry, 529-530 Fragment condensation in peptide synthesis, 1080... 

K. Kumar, A. Menon, and P. Sastry. Computer-assisted determination of elemental composition of fragments in mass spectra. Rapid Commun. Mass Spectrom., 6 585-591,1992. 

The five isotopes Sn- Sn give rise to a characteristic, easily recognisable isotopic distribution for tin-containing fragments in mass spectroscopic studies. 

The second key requirement for an imaging techniques is a contrast mechanism, which is some property of the system that varies spatially in the same way as the sample properties to be mapped, e.g. a specific fragment in mass spectrometry, a specific vibrational group frequency, surface reflectivity, etc. In many cases, especially for polymers, samples do not have much inherent contrast under a visible light microscope. Additional contrast is desired. 

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