Investigation of Lipid Distributions by Trifluoroacetic Acid-enhanced Desorption Electrospray Ionization Mass Spectrometry Imaging

A large number of lipids play an important role in the process of life, so it is important to simultaneously visualize multiple lipids by mass spectrometry imaging. By adding trifluoroacetic acid into the spray solvent of desorption electrospray ionization(DESI), the number of detectable lipids was increased from 59 to 71 in the mouse brain tissue sagittal section. This method could not only improve the detection sensitivity, but also suppress the formation of sodium and potassium adducts of lipids, to simplify spectrum interpretation and facilitate quantitative analysis. Furthermore, the result also revealed the spatial correlation among the lipids in the whole mouse brain tissue section as well as specific brain regions. The present protocol provides a new research method for exploring potential metabolic pathways between lipids, suggesting the potential application in neuroscience, clinical, and other fields.