Pd nanoparticles decorated thiol-functionalized MOF as an efficient matrix for differentiation and quantitation of oligosaccharide isomers by laser desorption/ionization mass spectrometry

Abstract

Oligosaccharides play a key role in many biological functions, and the accurate identification of oligosaccharide structures is an important prerequisite for a comprehensive understanding of the biological functions of oligosaccharides. MALDI-TOF/TOF tandem mass spectrometry has been considered as a potential technique for the structural characterization of oligosaccharides. In this work, palladium nanoparticles decorated thiol-functionalized metal organic framework nanocomposite (UiO-66-(SH)2@Pd NPs) was fabricated as an efficient matrix to assist laser desorption/ionization mass spectrometry (LDI-MS) for oligosaccharides analysis. The ionization efficiency of oligosaccharides was significantly improved owning to the synergistic effect of MOF and Pd nanoparticles, which is favorable for further oligosaccharide structure identification. By combining LDI-LIFT-TOF/TOF, 24 oligosaccharide isomers including disaccharides, trisaccharides and tetrasaccharides, were effectively distinguished. In addition, the relative quantification curves for isomeric oligosaccharides were established with good linear correlations. The method was successfully applied to the identification and quantification of sucrose and maltose in three batches of Asian ginseng and American ginseng respectively, showing potentiality of MOF materials and metal nanomaterials assisted structural analysis of oligosaccharide isomers.