UV-MALDI-TOF Mass Spectrometry Analysis of Carbohydrates Combining Doping Salts, Ga and nor-Harmane

ERRA BALSELLS, ROSA; S. L. GIUDICESSI; M. CABRERIZO, FRANCO; D. HIROTA; HIROSHI NONAMI

Sapporo, Hokaido, Japan, September 11 ? 15, 2006

Conferencia; Joint Conference on Environmental Engineering in Agriculture 2006; 2006

Japanese Society of Environment Control in Biology

UV-MALDI- and ESI-MS are a valuable techniques for the determination of high molecular mass when they are used with proteins while for carbohydrates still the techniques faces serious experimental problems. This limitation is probably related, at least in part, to the structural complexity and to the molecular interactions often found in the oligosaccharide moieties of these biopolymers. Furthermore, the isolated oligosaccharides include in its structure salts naturally present in cells, which can modify the results of the MS analysis. Salt impurities that may originate from the matrix, the analyte, solvents, glassware, surface of sample carriers, etc. may result in alkali metal adducts appearing in the UV-MALDI-MS. This is sometimes undesirable and can complicate the mass spectra. However, some species such as synthetic polymers and carbohydrates are primarily ionized by the formation of metal ion adducts (cationization). For this reason metal salts are often added to samples in order to enhance the analyte signals. Furthermore, cationization is somewhat matrix dependent. Understanding cationization mechanisms and the combined salt-matrix effects on it, are obviously required for better control of ion formation in UV-MALDI process.