Mass spectrometric imaging of small molecules

Small molecules are defined as low molecular weight organic compounds (typically <1000 Da), which could be either natural or artificial. Because established imaging methods are not able to selectively detect the positions, concentrations and structures of small molecules in biological samples, new methods have been developed. This review summarizes recent technological developments in one such method, mass spectrometric imaging (MSI). Lipids, hydrocarbons, sugars, phenolics, alkaloids, antibiotics, pharmaceutical and agrochemical compounds, bacterial, plant, and insect-defensive and semiochemical compounds are covered. Additionally, the latest MSI methods as well as sample preparation, imaging software, and medical and biological applications will be discussed.