LIQUID-CHROMATOGRAPHY THERMOSPRAY MASS-SPECTROMETRY OF MONOSACCHARIDES AND THEIR DERIVATIVES

Thermospray (TSP) mass spectrometry has proved to be a useful technique for analysing various highly polar compounds. The use of a quadrupole mass spectrometer equipped with a thermospray/plasmaspray interface in the analysis of more than 30 monosaccharides and sugar derivatives is described. A 1:1 mixture of methanol or acetonitrile and 0.1 m aqueous ammonium acetate as eluent at 1 cm3 min-1 affords the best results. The correct setting of the capillary tip temperature and repeller voltage was fundamental for the ionization of carbohydrates. The optimum values of these parameters were 240-250-degrees-C and 220-240 V, respectively. The thermospray mass spectra of most carbohydrates exhibit strong [M + NH4]+ ions which provide molecular mass information. The underivatized and derivatized monosaccharides could be grouped according to the presence or absence and the relative abundances of [M + NH4 - H2O]+, [M + H]+ and [M + NH4]+ ions.