ELECTROSTATIC VAPORIZATION ION-SOURCE - A SIMPLIFIED MODELING APPROACH

A better understanding of the Physics of an instrument can lead to an improvement of its performance. There are two levels in a modelling ap proach: A first level where one tries to identify the main physical ph enomena and performs simplified ''order of magnitude'' calculations, a nd a second level where sophisticated codes can be used. The topic of the paper is an approach of the first level applied to an electrospray /mass spectrometer instrument. The specific questions discussed are: T he mechanisms of formation of droplets: deformation of the free surfac e, total ion current, influence of the conductivity.... Evolution cf t he droplets: travelling distances, ion desorption, electrostatic split ting.... Ion migration towards the capillary inlet and effect of the s pace charge on the ion outlet.