3,4-Dimethoxycinnamic Acid as a Novel Matrix for Enhanced In Situ Detection and Imaging of Low-Molecular-Weight Compounds in Biological Tissues by MALDI-MSI

Low-molecular-weight (low-MW) compounds have many essential functions in biological processes, and the molecular imaging of as many low-MW compounds as possible is critical for understanding complex biological processes. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is an emerging molecular-imaging technology that enables determination of the spatial distributions and the relative abundances of diverse endogenous compounds in tissues. New matrices suitable for the imaging of low-MW compounds by MALDI-MSI are important for the technological advancement of tissue imaging. In this study, 3,4-dimethoxycinnamic acid (DMCA) was evaluated as a new matrix for enhanced low-MW compound detection by MALDI-MSI because of its strong ultraviolet absorption, low matrix-ion related interferences below m/z 500, and high ionization efficiency for the analysis of low-MW compounds. DMCA was successfully used for improved in situ detection of low-molecular-weight metabolites (m/z < 500) and...