A 3-POINT CALIBRATION PROCEDURE FOR MATRIX-ASSISTED LASER DESORPTION IONIZATION MASS-SPECTROMETRY UTILIZING MULTIPLY-CHARGED IONS AND THEIRMEAN INITIAL VELOCITIES/

This paper reports the results obtained by using a new calibration pro cedure for linear time-of-flight matrix-assisted laser desorption/ioni zation mass spectrometry (MALDI). The procedure takes into account the usual MALDI spectra structure by considering the multiply charged mol ecular ions and the mean initial velocities as a self calibrating prop erty. The mean velocities for all molecular ions are taken to be the s ame and the procedure is based on the solution of a number of equation s (at least three) which relate time-of-flight to mass. Three times be tter accuracy was obtained in comparison with the normal internal cali bration procedure.