Advanced Stored Waveform Inverse Fourier Transform Technique for a Matrix-assisted Laser Desorption/Ionization Quadrupole Ion Trap Mass Spectrometer

✍ Scribed by Vladimir M. Doroshenko; Robert J. Cotter

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 963 KB
• Volume: 10
• Category: Article
• ISSN: 0951-4198
• DOI: 10.1002/(sici)1097-0231(19960115)10:1<65::aid-rcm447>3.0.co;2-m

✦ Synopsis

The stored waveform inverse Fourier transform (SWIFT) technique is used for broadband excitation of ions in an ion-trap mass spectrometer to perform mass-selective accumulation, isolation, and fragmentation of peptide ions formed by matrix-assisted laser desorptionlionization. Unit mass resolution is achieved for isolation of ions in the range of m/z up to 1300 using a two-step isolation technique with stretched-in-time narrow band SWIFT pulses at the second stage. The effect of 'stretched-in-time' waveforms is similar to that observed previously for mass-scan-rate reduction. The asymmetry phenomenon resulting from the stretched ion-trap electrode geometry is observed during application of normal and time-reversed waveforms and is similar to the asymmetry effects observed for forward and reverse mass scans in the resonance ejection mode. Mass-selective accumulation of ions from multiple laser shots was accomplished using a method described earlier that involves increasing the trapping voltage during ion introduction for more efficient trapping of ions.