High Mass-Resolution MALDI-imaging MS for Drug Metabolism in Tissue Using the JMS-S3000
Imaging by using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-Imaging) has been expanded during the last decade into biological applications in order to assess the distribution of proteins, peptides, lipids, drugs, and metabolites in tissue specimens. For a drug metabolism analysis, MALDI-Imaging has an advantage in that it can visualize the distributions of drugs and metabolites without using radio isotopes which are used for whole body autoradiography.
In MALDI-Imaging measurements, a laser is used to irradiate each point across a sample surface in order to acquire a mass spectrum for a given location. By combining the mass spectra with their two-dimensional position information, localization of compounds with inherent molecular weights can be visualized or the mass spectra for certain regions of interests (ROIs) can be created.
The JMS-S3000 SpiralTOF is a MALDI-TOFMS, which utilizes the JEOL patented spiral ion optics system. It has a 5-10 times longer flight path than the typical reflectron type MALDI-TOFMS. As a result, it can achieve high mass-resolution to separate peaks that have the same nominal mass but have different exact masses (isobaric separation). This feature is particularly effective for MALDI-Imaging for drug metabolism, which typically consist of relatively low molecular weight compounds which are often interfered with by matrix compounds and/or surface contaminants.