OPTIMIZATION OF CONDITIONS FOR THE ANALYSIS OF A PEPTIDE MIXTURE AND A TRYPTIC DIGEST OF CYTOCHROME C BY CAPILLARY ELECTROPHORESIS ELECTROSPRAY-IONIZATION MASS SPECTROMETRY WITH AN IMPROVED LIQUID-SHEATH PROBE

摘要

Capillary electrophoresis (CE) has been interfaced with a quadrupole mass spectrometer using electrospray (ES) ionization in order to rapidly analyze a peptide mixture and a tryptic map of cytochrome c. A sheath liquid probe has been developed which allows the easy connection of CE with ES and the manipulation of important experimental parameters such as the position of the CE column exit relative to the sheath flow tube exit. In addition, the atmospheric region of the ion source has been modified so that glass windows replace the walls of the chamber, and the electrospray process itself is fully visible during operation. Detection limits for a biologically active peptide, leucine enkephalin, were determined to be 200 fmol in the scan mode of operation and 1.5 fmol in the selected-ion monitoring mode of operation. [References: 15]