Thermal decomposition study of 4-methyloxybenzyl-glycoside by TG/DTA and on-line pyrolysis-photoionization mass spectrometry

Abstract A glycosidic bond flavor precursor of 4-methyloxybenzyl-2, 3, 4, 6-tetra-O-acetyl-β-D-glucopyranoside (MBGL) was synthesized by the modified Koenigs-Knorr reaction. The thermal decomposition behaviour and pyrolysis intermediate products of the glycoside were studied by simultaneous thermo-gravimetric/differential thermal analysis (TG/DTA) and synchrotron vacuum ultraviolet (VUV) photoionization mass spectrometry (PIMS). TG/DTA gave a TG-DTG curve, which showed the Tp of the glycoside was 246.7 ℃ with a largest mass loss rate. The total mass loss was 97.8%. The PIMS was used to identify the pyrolysis products of the MBGL at different temperatures. Some important pyrolysis intermediates, such as the ions of 4-methyloxybenzyl group at m/z 122 and glycon moiety at m/z 347, were detected by the PIMS. The results indicated that the MBGL was probably showed a different pyrolysis way compared with other glycoside. This work reported a good application of synchrotron VUV PIMS in thermal decomposition study of glycoside flavor precursor.