PRESERVATION OF D-GLUCOSE-OLIGOSACCHARIDES IN CELLULOSE CHARS

Microcrystalline cellulose was charred anaerobically at atmospheric pr essure and at different temperatures ranging from 190 to 390-degrees-C . Temperature-resolved, in-source-filament pyrolysis, ammonia chemical ionisation mass spectrometry (Py-CIMS) of these chars shows ion serie s of ammonium adduct ions of anhydro-oligosaccharides. These anhydro-o ligosaccharides were identified by high-performance liquid chromatogra phy (HPLC) of derivatised, off-line, Curie-point-pyrolysis condensates as beta-(1 --> 4)-linked glucose oligosaccharides with an 1,6-anhydro sugar terminal at the reducing end. These anhydro-glucooligosaccharide s were observed in chars even after 2.5 h heating at 270-degrees-C. Th e relative amount of preserved glucose in the chars was determined by acid hydrolysis. Coexistence of two solid phases: (i) residual crystal line cellulose and (ii) a condensed thermostable phase was observed in chars derived from cellulose by heating at 250, 270, and 290-degrees- C. It is believed that the formation of this new condensed phase is in itiated in the thermally induced, amorphous domains of cellulose. No e ther-bonded products of inter- and intra-chain crosslinking reactions were detected in the acid hydrolysates of the chars.