Protonation reactions and the formation of adducts

The reagent gas BH can lead to an adduct ion [A4-BH], the abundance of which is directly related to source temperature and pressure conditions and to the standard enthalpy of the reaction. Then, protonated molecular ions (MH ) are often produced. 

In addition to the interest of obtaining MH ions, it should be noted that in general fragment ions are characterized by an odd number of electrons and are formed by the elimination of neutral molecules, either by simple rupture or by hydrogen transfer. 

The fragmentations are very often complementary to those produced in El and may be of considerable importance for the determination of complex structures, especially peptides [33] (Fig. 1), carbohydrates [34], etc. 

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