M. L. Manier, J. M. Spraggins, M. L. Reyzer, J. L. Norris and R. M. Caprioli
Imaging Mass Spectrometry is increasingly being applied to the study of small endogenous compounds, including metabolites, neurotransmitters, lipids and other compounds as well. However, due to the high degree of structural homology and the lack of true “blank” samples, generation of images of unequivocal molecular identity is challenging. In this special feature perspective article, Richard Caprioli and colleagues at Vanderbilt University Medical Center discuss these challenges and describe an analytical strategy that combines a number of advanced instrumental methods to identify and confirm the accurate spatial localization of select amino acids and amine-containing metabolites. By combining derivatization, MSn, and accurate mass, followed by confirmation via HPLC-MS, they are able to demonstrate the localization of several endogenous metabolites in biological tissue specimens.