ENHANCED MASS RESOLUTION IN MATRIX-ASSISTED LASER DESORPTION IONIZATION LINEAR TIME-OF-FLIGHT MASS-SPECTROMETRY/

The limits of performance of a linear time-of-flight mass spectrometer using matrix-assisted laser desorption/ionization have been tested. E ffects of the pressure in the vacuum system and the sampling rate of t he digital oscilloscopes on mass resolution have been investigated. Sp ectra recorded at different pressures and at sampling rates of 100 MS s(-1), 400 MS s(-1) and 1 GS s(-1) are compared. A mass resolving powe r m/Delta m (full width at half maximum) of 900 to 2400 has been achie ved for a selection of peptides and proteins within a mass range from 800 to 6000 Da.