DBDA Matrix Increases Ion Abundance of Fatty Acids and Sulfatides in MALDI-TOF and Mass Spectrometry Imaging Studies.

Abstract

MALDI-TOF MS is a powerful tool to analyze biomolecules, owing to its soft ionization nature that generally results in simple spectra of singly charged ions. Implementation of the technology in the imaging mode provides a means to spatially map analytes in situ. Recently, a new matrix, DBDA (N1,N4-dibenzylidenebenzene-1,4-diamine) was reported to facilitate the ionization of free fatty acids in negative ion mode. Building on this finding, we sought to implement DBDA for MALDI mass spectrometry imaging studies in brain tissue and successfully map oleic acid, palmitic acid, stearic acid, docosahexaenoic acid, and arachidonic acid using mouse brain sections. Moreover, we hypothesized that DBDA would provide superior ionization for sulfatides, a class of sulfolipids with multiple biological functions. Herein, we also demonstrate that DBDA is ideal for MALDI mass spectrometry imaging of fatty acids and sulfatides in brain tissue sections. Additionally, we show enhanced ionization of sulfatides using DBDA compared with three different traditionally used MALDI matrices. Together these results provide new opportunities for studies to measure sulfatides by MALDI-TOF MS.