Fragmentation fragmentation

Fragmentation Fragmentation occurs on both sides of the carbonyl group. For example, in acetophenone, the major ions occur at masses 77, 105, and 120 (see Figure 20.3). Ions at m/z 39, 50, and 51 also suggest the presence of an aromatic ring. Aromatic compounds, such as quinone, tetralone, and anthraquinone, readily lose CO. 

Cone-voltage fragmentation Fragmentation of ions, commonly produced by APCl or electrospray ionization, effected by the application of a voltage within the source of the mass spectrometer. 

Small molecular fragments Small molecular fragments Fragments with linkage points... 

The production of ions from neutral compounds and the examination of how these ions subsequently fragment is fundamental to mass spectrometry. Neutral sample molecules can be ionized by a variety of processes. The most important of these for the production of positively charged species is the removal of an electron or the addition of one or more protons to give either molecular ions (M+ ) or protonated molecular species (M+nH)"+. This initial stage of ionization is often followed by fragmentation to produce ionized fragments, fragment ions . 

D-[l- C]Xylose was subjected to boiling in 4 M aqueous sodium hydroxide. The resulting mixture contained 2,4-dihydroxybutanoic acid, lactic acid, and D-a,j8-xylometasaccharinic acid. The almost uniform distribution of the C label among the carbon atoms of 2,4-dihydroxybutanoic acid indicated that this acid is probably formed by the recombination of completely isomerized, two-carbon fragments. Fragmentation of D-xylose occurred mainly at one of the central bonds, C-2-C-3 or C-3-C-4. 

Time delayed fragmentation (TDE) Resolving (fixed) Trap/no fragment Fragment/trap/scan ... 

Primary fragmentation Fragments generated by the initial explosion or blast. 

Secondary fragmentation Fragments produced by primary fragments striking objects and imparting explosive inertia to them. 

The presence of an oxygen atom can be deduced from strong peaks at m/z 31, 45, 59, 73,. ... These peaks represent the RO+ and ROCH2+ fragments. Fragmentation occurs in two principal ways ... 

DNA is digested into fragments fragments inserted into BACs. 

Stationary spectroscopy on the C and D states of Na3 already indicated the onset of photoinduced fragmentation. Fragmentation becomes more important as the cluster size increases. As a result, nondissociative electronic excitation processes have not yet been observed for free metal clusters larger than trimers [20]. An alternative to conventional spectroscopy of such bound-free transitions was provided by depletion spectroscopy [2]. A deep insight into the dynamics of such photoinduced cluster fragmentation, however, is obtained with ultrafast observation schemes. The principle of such an... 

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