CAPILLARY ELECTROPHORESIS ELECTROSPRAY-IONIZATION ION-TRAP MASS-SPECTROMETRY USING A SHEATHLESS INTERFACE

The sensitivity that can be obtained with the quadrupole ion trap for on-line CE analysis using a sheathless electrospray interface and gold -tipped columns is examined. Capillaries of different i.d. are compare d in continuous infusion experiments and the effects of sheath solvent s on the signal for some peptides and proteins are illustrated. The sh eathless CE/ITMS system using 20 mu m i.d. columns is shown to provide mid-attomole detection levels for leucine enkephalin in total ion ele ctropherograms under full scan conditions. Good quality MS/MS spectra are also obtained for low femtomole injections of this peptide. (C) 19 95 John Wiley & Sons, Inc.