Calibration of the Internal Energy Distribution of Ions Produced by Electrospray

The internal energy deposited in the ions in the source of mass spectrometer governs their fragmentation and therefore the content of the spectra. When the ionization conditions are well defined and reproductible, the elaboration of databases benefits the use of the method. In electrospray, however, the source conditions are not strictly defined. The elaboration of spectra databases therefore requires a calibration of internal energy of the ions. In this article, a method for the calibration of the internal energy of the ions in electrospray is presented, developed using fragmentation reactions of a set of probe ions (benzylpyridinium salts) under various conditions.