PROTEIN IDENTIFICATION BY SOLID-PHASE MICROEXTRACTION-CAPILLARY ZONE ELECTROPHORESIS-MICROELECTROSPRAY-TANDEM MASS-SPECTROMETRY

We describe an analytical system for the rapid identification of prote ins by correlation of tandem mass spectra with protein sequence databa ses. The system consists of an integrated solid phase microextraction/ capillary zone electrophoresis peptide separation device that is conne cted through a microelectrospray ion source to a tandem mass spectrome ter. 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 analysi s by collision-induced dissociation. Using this system, we have identi fied low nanogram amounts of yeast proteins separated by high-resoluti on two-dimensional gel electrophoresis.