Use of enzymatic digestion and chemical methylation followed by matrix-assisted laser desorption / ionisation (MALDI) mass spectrometry to sequence a 60 kDa commercial fraction of cellulose acetate

Cellulose acetate was characterized by using enzyme in both digestion and chemical derivation and acetolysis. The fragments were normalised and compared on an anhydroglucose scale, using mass spectrometry to identify the different sized fragments. It was determined that at least two sub-populations for cellulose acetate existed within the parent. The macroscopic effect of this variation in the degree of acetylation will be a modification of the structural properties of the polymer chains. It was found that through comparison with enzyme-based degradation, an estimation of the acetylation topography of the cellulose acetate fraction could be made. Enzyme degradation produced a number of oligosaccharides of more than 10 glucose units, presumably resistant to enzyme degradation because they contained acetate groups. Chemical hydrolysis gave a random ladder of short sequences of mainly 3-4 glucose units some of which had a high methyl ether content, that were analysed by mass and converted to an anhydroglucose mass scale. This approach could be used to demonstrate differences between large biopolymers of cellulose acetate that previously gave an overall average rather than a specific ladder average.