Mass Spectrometry Imaging Analysis of Lipids in Mouse Brain Tissue Section
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.
Statistical Analysis of Mass Spectrometry Imaging Data by using SCiLS Lab MVS
Advanced statistical data analysis was performed based on all of the mass spectral peaks detected in the data above by using SCiLS Lab MVS. Segmentation of the characteristic regions and extraction of the mass spectrum from each segment facilitated by the high mass-resolving power of the JMS-S3000 SpiralTOF™-plus have been achieved.
Result of pLSA (probabilistic latent semantic analysis)
Segmentation
Relationship between pLSA score plot and Segmentation
Mass spectra from respective segments
Analyzed with SCiLS Lab MVS, Version 2020b Premium3D
Mass spectrometry imaging data analysis of synthetic polymers by using msMicroImager™
In conventional MS imaging, a MS image is extracted by specifying a specific m/z range. However, since polymers are polydisperse and have molecular weight distributions, the conventional method can generate only a mass image of a specific degree of polymerization, and the spatial distribution of the polymer as a whole cannot be visualized. To solve this problem, msMicroImager™ can generate an image with the number average molecular weight (Mn), weight average molecular weight (Mw), and polydispersity (D) of the polymer. This makes it possible to visualize the spatial distribution of polymers more intuitively by consolidating hundreds of mass images derived from each degree of polymerization / isotope peak into three images.
MS Imaging of polyethylene glycols having different molecular weight distributions (MSTips No.305)
A conventional method can visualize the distribution of a polymer species with a specific degree of polymerization.
Mass Spectrometry Imaging Analysis of Polymers by Combining msMicroImager™ and msRepeatFinder