IMPROVING THE RESOLUTION OF MATRIX-ASSISTED LASER DESORPTION IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETRY BY EXPLOITING THE CORRELATION BETWEEN ION POSITION AND VELOCITY/

By taking into account the correlation between the positions and veloc ities of desorbed ions in the source region of a time-of-flight mass s pectrometer and by including this relationship in the equations used t o determine space-focusing conditions, it is predicted that matrix-ass isted laser desorption/ionization time-of-flight (MALDI-TOF) mass spec tral resolution can be improved significantly. Experiments involving M ALDI of two proteins, insulin and ubiquitin, demonstrate the validity of this concept. Adduct formation does not limit mass spectral resolut ion in these two cases.