Chemical and biochemical applications of MALDI TOF-MS based on analyzing the small organic compounds.

This review focuses on the recent applications of matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI TOF-MS) technologies for analysis of small molecular compounds (SMCs) on qualitative and quantitative levels to provide valuable information for the relative chemical and biochemical researches. We summarized the approaches to minimize the interference in low m/z range and ion suppression effects by adding chemical reagents, sample cleaning and preparation, matrix selection and performing chromatographic separation before MALDI TOF-MS analysis. Meanwhile, we discussed the strategies to enhance the MALDI TOF-MS detection sensitivity and selectivity by derivatization to attach the "charge tags" to SMCs. In addition, the mass spectrometric imaging (MSI) methods for locating the target SMCs in bio-tissues by MALDI TOF-MS were reviewed. Furthermore, the applications of MALDI TOF-MS for monitoring enzyme reactions and the screening of their inhibitors were also presented. Finally, the chemical applications of MALDI TOF-MS on characterization of small molecular transition-metal complexes and monitoring the organic reactions, especially the polymerization reactions, were discussed.