An on-line preconcentrator and the evaluation of electrospray interfaces for the capillary electrophoresis mass spectrometry of peptides

A unique preconcentrator was constructed for on-line preconcentration using capillary electrophoresis generating concentration detection limits for pe ptides in the mid-picomolar range. Several common sheathless electrospray c onfigurations were constructed in conjunction with the preconcentrator and were compared. It was found that a palladium wire interface was the most re liable interface and the problems encountered using this interface are disc ussed. A tryptic digest of the myosin I heavy chain kinase that contains tw o phosphopeptides was separated by capillary electrophoresis using this int erface and the on-line preconcentrator, Copyright (C) 1999 John Wiley & Son s, Ltd.