Mouse brain sections contain a variety of lipid classes. A mass spectrum obtained from the tissue section is highly complex, especially in the region of m/z 700 - 1,000. Many of the peaks in the mass spectrum are less than 10% of the base peak, representing minor components. MALDI MS imaging of lipids requires a mass-resolving power high enough to separate the minor peaks from interferences. The bottom mass spectrum below shows the expansion of m/z 820 - 823. Many peaks were separated from each other by less than 0.1 u. The high mass resolving power of the SpiralTOF™-plus clearly separated these isobaric peaks, thus allowing the elucidation of 4 lipid elemental compositions. Moreover, each lipid clearly showed a different spatial distribution. Elucidation of elemental compositions and accurate determination of spatial distributions for each lipid would be difficult with a conventional reflectron TOFMS with moderate mass-resolving power.
The data were acquired in a joint research project with the Mass Spectrometry Group, Project Research Center for Fundamental Sciences, Graduate School of Science, Osaka University.
The tissue section specimen was provided by Awazu laboratory, Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University.