Protonation of a molecule

The experiments are used to recognise the spatial proximity among the protons of a molecule. The experiments are useful if a large number or all proton-proton interactions within a molecule or between molecules are of interest. If the spatial arrangement of only a few protons are of interest, a common situation with small molecules, the ID NOE experiment with its inherent higher sensitivity offers a better alternative. 

Thus, the reaction is more efficient when PA(M) > PA(B). The PA is measured as the heat liberated during the protonation of a molecule. The CH4-CI transfers more energy than does the f-C4Hio-CI therefore, the former produces more fragment ions. 

Chemical ionization (Cl) has been used in the selected ion monitoring mode for the analysis of PCB mixtures in environmental sample extracts [34,38]. Chemical ionization is the protonation of a molecule to form a pseudomolecular ion with little accompanying fragmentation. However, Cl reagent ion species are formed concurrently in ion/molecule reactions with other ion species thus, in a given Cl system, several reagent ion species can be found. These species usually differ with respect to electron affinity [47] and the propensity with which the proton... 

The protonation of a molecule, its transformation into an ion ofien makes it labile and creates possibilities for transformation into these or other products. Therefore, acid catalysis is widely abundant, acids catalyze the very diverse reactions of addition, substitution, and elimination. The simplest scheme of the acid-catalytic reaction includes two steps... 

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