Improved mass accuracy for higher mass peptides by using SWIFT excitation for MALDI-FTICR mass spectrometry.
Stepwise-external calibration has previously been shown to produce sub part-per-million (ppm) mass accuracy for the MALDI-FTICR/MS analyses of peptides up to m/z 2500. The present work extends these results to ions up to m/z 4000. Mass measurement errors for ions of higher mass-to-charge are larger than for ions below m/z 2500 when using conventional chirp excitation to detect ions. Mass accuracy obtained by using stored waveform inverse Fourier transform (SWIFT) excitation was evaluated and compared with chirp excitation. Analysis of measurement errors reveals that SWIFT excitation provides smaller deviations from the calibration equation and better mass accuracy than chirp excitation for a wide mass range and for widely varying ion populations.
Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA.
Li
L
Jing
Chunyan
C
Li
Richard L
RL
Wong
Desmond A
DA
Kaplan
I Jonathan
IJ
Amster
D000818:Animals; D002138:Calibration; D002417:Cattle; D002645:Chickens; D005583:Fourier Analysis; D010047:Ovalbumin / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D015203:Reproducibility of Results; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012815:Signal Processing, Computer-Assisted; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D053719:Tandem Mass Spectrometry
D010455:Peptides; D012710:Serum Albumin, Bovine; D010047:Ovalbumin