Recent advances of nanomaterials assisted negative ion laser desorption/ionization-time-of-flight mass spectrometry in the analysis of small molecules

Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) is a soft ionization technique that has been widely used in the analysis of macromolecules, such as proteins, peptides, nucleic acids and polymers. However, it has difficulty in the analysis of small molecules with relative molecular masses below 700 Da because of the interferences from the matrix. To overcome these drawbacks, interference-free nanomaterials assisted laser desorption/ionization (LDI) has been paid more and more attention. Compared with the multiple peaks of one compound obtained in the positive ion mode, nanomaterials assisted negative ion LDI provides only deprotonated ion peak. In this article, recent advances of nanomaterials assisted negative ion LDI in the analysis of small molecules are reviewed.