Imaging of peptides in the rat brain using MALDI-FTICR mass spectrometry

Abstract

Analytical methods are pursued to measure the identity and location of biomolecules down to the subcellular ( m) level. Available mass spectrometric imaging methods either compromise localization accuracy or identification accuracy in their analysis of surface biomolecules. In this study, imaging FTICR-MS is applied for the spatially resolved mass analysis of rat brain tissue with the aim to optimize protein identification by the high mass accuracy and online MS/MS capabilities of the technique. Mass accuracies up to 6 ppm were obtained in the direct MALDI-analysis of the tissue together with a spatial resolution of 200 m. The spatial distributions of biomolecules differing in mass by less than 0.1 Da could be resolved, and are shown to differ significantly. Online MS/MS analysis of selected ions was demonstrated. A comparison of the FTICR-MS imaging results with stigmatic TOF imaging on the same sample is presented. To reduce the extended measuring times involved, it is recommended to restrict the FTICR-MS analyses to areas of interest as can be preselected by other, faster imaging methods. (J Am Soc Mass Spectrom 2007, 18, 145-151)

Enhancement of protein sensitivity for MALDI imaging mass spectrometry after chemical treatment of tissue sections

“…Current systems with enhanced electronics and improved acquisition systems are now equipped with solid-state Nd:YAG lasers (355 nm), functioning at repetition rates as high as 200 to 300 Hz [25,34]. IMS has also been successfully performed on other types of commercially available MS instruments, such as QqTOF, ion traps, and more recently Fourier transform ion cyclotron resonance (FT-ICR) systems [7,35,36]. Whereas early software programs for IMS data acquisition and visualization were written "in-house" [31,37], today almost every commercially available MALDI-based mass spectrometer is "imaging capable" and can be equipped with software for automated data acquisition, image reconstruction, and visualization.…”

Vacuum compatible sample positioning device for matrix assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry imaging

“…Moreover, the flexibility of scheduling the stage movement allows for introduction of internal calibrants, 28, 29 thus utilizing both high resolving power and mass accuracy of FT-ICR MS for MSI experiments. 30,31 Reported spatial resolution, although substantially improved, was by no means limited by the device positional accuracy. Reduction of the raster size in oversampling experiments (Figs.…”

Application of Matrix-Assisted Laser Desorption/Ionization Imaging Mass Spectrometry

“…In general, the first system is used to select a precursor ion for fragmentation, while the second T O F s y s t e m i s e m p l o y e d f o r f r a g m e n t a n alysis. Other mass analyzers (and their combinations), such as linear ion trap (LIT) (Landgraf et al, 2009;Wiseman et al, 2006;Zaima et al, 2010a), triple quadrupole (QqQ) (Hopfgartner et al, 2009;Porta et al, 2011), and Fourier transform ion cyclotron resonance (FTICR) (Taban et al, 2007), are used for MALDI-IMS. The advantages of commercially available LIT instruments are miniaturization, capability of sample analysis on nonconductive glass slides, MALDI performance at intermediate pressure, and superior performance on multistage MS.…”