| Abstract
| - A multiplexing method for performing MS/MS on multiplepeptide ions simultaneously in a quadrupole ion trapmass spectrometer (QITMS) has been developed. Thismethod takes advantage of the inherent mass bias associated with ion accumulation in the QITMS to encode theintensity of precursor ions in a way that allows thecorresponding product ions to be identified. The intensityencoding scheme utilizes the Gaussian distributions thatcharacterize the relationship between ion intensities andrf trapping voltages during ion accumulation. This straightforward approach uses only two arbitrary waveforms, onefor isolation and one for dissociation, to gather production spectra from N precursor ions in as little as twoproduct ion spectra. In the example used to illustrate thismethod, 66% of the product ions from five differentprecursor peptide ions were correctly correlated using themultiplexing approach. Of the remaining 34% of theproduct ions, only 6% were misidentified, while 28% ofthe product ions failed to be identified because either theyhad too low intensity or they had the same m/z ratio asone of the precursor ions or the same m/z ratio as aproduct ion from a different precursor ion. This methodhas the potential to increase sample throughput, reducetotal analysis times, and increase signal-to-noise ratios ascompared to conventional MS/MS methods.
|
