Molecular weight determination by cationisation

Publisher Website
Google Scholar
Abstract
In General cationised molecules are more stable than redical molecular ions or protonated molecules. The fragmentation of the polar molecules resulting from a cationsation by for instance alkali ions, has a higher activation energy than splitting off fuctional groups after a protonation. Cationisation is therefore an intersting tool for the determination of molecular weights. Three different methods for achiving a cationisation are described and discussed: (1) field‐indiced cationisation at low anode temperatures using a heterogenous reaction of the molecules in the gas phase with molecules of a salt in the adsorption layer on the field anode; (2) a largely thermally induced catisation at high emitter temperatures and low electric fields; (3) a cationisation, causing less thermal excitation to the molecules, using the field desorption technique.