Metabolite Imaging Using Matrix-Enhanced Surface-Assisted Laser Desorption/Ionization Mass Spectrometry (ME-SALDI-MS)

We describe here the use of a hybrid ionization approach, matrix-enhanced surface-assisted laser desorption/ionization mass spectrometry (ME-SALDI-MS) in bioimaging. ME-SALDI combines the strengths of traditional matrix-assisted laser desorption/ionization (MALDI) and SALDI and enables successful MS imaging of low-mass species with improved detection sensitivity. Using 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) as the MS standard, MS performances of MALDI, SALDI, and ME-SALDI are systematically compared. The analyte desorption and ionization mechanism in ME-SALDI is qualitatively speculated based oil the observation of significantly reduced matrix background and improved survival yields of molecular ions. Improvements in detection sensitivity of low-mass species using ME-SALDI over MALDI in imaging are demonstrated with mouse heart and brain tissues. (J Am Soc Mass Spectrom 2009, 20, 80-88) (C) 2009 Published by Elsevier Inc. on behalf of American Society for Mass Spectrometry