Protein identification by solid phase microextraction-capillary zone electrophoresis-microelectrospray-tandem mass spectrometry

We describe an analytical system for the rapid identification of proteins by correlation of tandem mass spectra with protein sequence databases. The system consists of an integrated solid phase microextraction/capillary zone electrophoresis peptide separation device that is connected through a microelectrospray ion source to a tandem mass spectrometer. The limits of detection are 660 amol of sample at a concentration limit of <33 amol/mu l for peptide mass measurement, and <10 fmol of sample, at a concentration limit of <300 amol/mu l for peptide analysis by collision-induced dissociation. Using this system, we have identified low nanogram amounts of yeast proteins separated by high-resolution two-dimensional gel electrophoresis.