System and method for calibrating time-of-flight mass spectra

Abstract

A time-of-flight mass spectra calibration technique uses time-of-flight mass spectrometer instrument operational parameters and known mass and measured time-of-flight data pairs to optimize values of chosen ones of the instrument operational parameters. Electrostatic time-of-flight calculations are conducted in conjunction with an iterative procedure, preferably a simplex optimization procedure, to thereby minimize a residual error between the electrostatic time-of-flight calculations and the measured time-of-flight data values for each of the known mass values. While conventional curve fitting mass calibration techniques are devoid of information that describe ion behavior, the mass calibration technique of the present invention, by contrast, takes into account all of the instrument operational parameters in arriving at a final calibration. Because the electrostatic TOF calculation is a description of ion behavior in an actual TOF mass spectrometer instrument rather than a polynomial representation of a curve, it is well behaved and does not contain any instabilities where unpredictable calibration errors might occur. Moreover, unlike conventional curve fitting mass calibration techniques, the mass calibration technique of the present invention maintains mass accuracy in extrapolated mass ranges.