title: Mass recalibration of FT-ICR mass spectrometry imaging data using the average frequency shift of ambient ions.
abstract: Achieving and maintaining high mass measurement accuracy (MMA) throughout a mass spectrometry imaging (MSI) experiment is vital to the identification of the observed ions. However, when using FTMS instruments, fluctuations in the total ion abundance at each pixel due to inherent biological variation in the tissue section can introduce space charge effects that systematically shift the observed mass. Herein we apply a recalibration based on the observed cyclotron frequency shift of ions found in the ambient laboratory environment, polydimethylcyclosiloxanes (PDMS). This calibration method is capable of achieving part per billion (ppb) mass accuracy with relatively high precision for an infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) MSI dataset. Comparisons with previously published mass calibration approaches are also presented.
authors.affiliation: W. M. Keck FT-ICR Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Jeremy A
authors.initials: JA
authors.lastname: Barry
authors.forename: Guillaume
authors.initials: G
authors.lastname: Robichaud
authors.forename: David C
authors.initials: DC
authors.lastname: Muddiman
mesh_terms: D000818:Animals; D001921:Brain / Q000033:anatomy & histology; D001923:Brain Chemistry; D002138:Calibration; D017357:Cyclotrons; D005583:Fourier Analysis; D007259:Infrared Rays; D007477:Ions; D013058:Mass Spectrometry / Q000379:methods* / Q000706:statistics & numerical data; D051379:Mice; D057054:Molecular Imaging / Q000379:methods* / Q000706:statistics & numerical data; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods / Q000706:statistics & numerical data; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods / Q000706:statistics & numerical data
chemical_list: D007477:Ions