Self-calibration of spectra using precursor mass to charge ratio and fragment mass to charge ratio known differences

摘要

A method of checking or adjusting the calibration of a mass spectrometer comprises fragmenting parent ions and determining a mass loss difference between the parent ions and neutral loss ions in the fragment ion mass spectral data. If the mass loss difference does not correspond with an expected or pre-determined mass loss difference, then one or more calibration parameters is adjusted. Alternatively, the method may comprise reacting precursor ions and using a mass gain difference between the precursor ions and adduct ions to determine whether a calibration parameter is adjusted. The method may comprise plotting the mass to charge ratio of fragment or product ions as a function of the mass to charge ratio of parent or precursor ions, identifying trends lines in the data, and determining the mass loss difference or mass gain difference using a best fit line. More than one neutral loss or adduct ions may be used.