title: Attomole biomolecule mass analysis by matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance.
abstract: Significantly improved sensitivity for analysis of biomolecules by MALDI FT-ICR mass spectrometry is achieved by (i) microscope-monitored sample deposition onto a small indentation on the probe tip and (ii) multiple remeasurement of ions from a single laser shot. A simple modification to the solids probe tip allows for microdeposition of a few amols of analyte onto small indentation spots previously aligned with the laser beam. Ion multiple remeasurement of the same ion packet enhances the signal-to-noise ratio and thus extends the achievable FT-ICR MS detection limit. We demonstrate that FT-ICR can be used to detect parent and structurally significant fragment ions of peptides and phospholipids at low amol amounts. Positive ion mass spectra for approximately 90 amol of a mixture of angiotensin II and bradykinin, approximately 40 amol of dipalmitoylglycerophosphatidylcholine, and approximately 8 amol of substance P constitute the lowest reported detection limits to date for FT-ICR mass analysis of MALDI-generated ions.
authors.affiliation: Center for Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, Florida State University, Tallahassee 32310, USA.
authors.forename: T
authors.initials: T
authors.lastname: Solouki
authors.forename: J A
authors.initials: JA
authors.lastname: Marto
authors.forename: F M
authors.initials: FM
authors.lastname: White
authors.forename: S
authors.initials: S
authors.lastname: Guan
authors.forename: A G
authors.initials: AG
authors.lastname: Marshall
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000031:analogs & derivatives / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013373:Substance P / Q000737:chemistry
chemical_list: D015060:1,2-Dipalmitoylphosphatidylcholine; D013373:Substance P; C039559:1,3-dipalmitoyl-2-phosphatidylcholine