  A detailed study of the transfer of ions in transfer capillaries of
electrospray ion sources is presented. The laminar flow field for various
capillary sizes and wall temperatures is calculated. It forms the base of ion
transfer simulation of a large number of ions with space charge. This allows to
study the thermodynamical conditions of the ions during transfer, which are
found to vary strongly with the capillary dimensions. The dependence of mass
flow and ion current on the size of the capillary is presented. Simple scaling
relations are derived and tested. The method also allows to predict a transfer
bias between different ion species depending on the difference in ion mobility
and the composition of transferred ions.
