Paper accepted: Degree of acetylation of chitosans determined by size exclusion chromatography coupled to UV and refractive index detection

Dr. Stefan Cord-Landwehr, supported by Dr. Margareta Hellmann, has again come up with a new method for chitosan analysis which has just been accepted for publication in the renowned journal Carbohydrate Polymers. This time, it is for the determination of the degree of acetylation. The method is surprisingly simple, so much so that it is actually surprising that it has not been invented much earlier. Well, perhaps not so surprising, because as simple as the idea sounds, its realization did require quite some adjustments. A chitosan sample is separated by size exclusion chromatography coupled to an RI and a UV detector. The RI detector informs about the amount of sample eluting from the column, while the UV detector simultaneously informs about the DA of the chitosan eluting. When performed on an HPLC system, the analysis requires only very little sample (micrograms) and is very fast (10 min, no sample preparation required). Moreover, as the chitosans in the sample are separated according to their size, the method allows to determine whether all chitosans present have the same or different DAs. The former typically occurs when a chitosan polymer is degraded using acid, the latter upon enzymatic hydrolysis, with potentially strong impact on bioactivities. And as our system also includes a mass spectrometer as an additional detector, we can even analyse in detail which oligomers are present in the sample. Once more, Stefan proves himself to be Master of Chitosan Analysis!