COMPARISON OF THE INTERNAL ENERGY-DISTRIBUTIONS OF IONS PRODUCED BY DIFFERENT ELECTROSPRAY SOURCES

The internal energies of the emitted ions can be modulated in an elect rospray source through different experimental conditions. However, the fragmentation pattern depends also on conditions that cannot be contr olled by the operator, e.g. the geometry of the source or the mode of transfer of the ions. These differences make difficult the comparison of the electrospray mass spectra obtained with different mass spectrom eters. A method for the calibration of the internal energies of ions p roduced by an electrospray source has been presented previously to stu dy the influence of experimental conditions on the internal energies o f the ions. The method permits the calibration of individual working c onditions. In this work, new results were obtained with modified value s of fragmentation energy taking into account the kinetic shift of the thermometer ions, The internal energy distributions are compared for different instruments with different geometries, and are measured unde r different accelerating and focusing conditions. (C) 1998 John Wiley & Sons, Ltd.