Biodegradable high molecular weight polymers constitute an important class of biomedical materials for drug delivery as well as tissue engineering applications. Particularly, polysaccharide-based polymers modified with therapeutic agents have received significant attention as coatings for medical devices. As a result of stringent FDA approval requirements for these applications, complete characterization of the polymer including its initial material and the degradation products is crucial. Current characterization of these materials is limited to GPC-RI and MALDI-MS. These methods of characterization are not sufficient for polysaccharide-based materials because the process of synthesizing them from bacteria leads to a distribution of oligomers in a range that could go undetected by GPC. Furthermore, MALDI ionization is difficult to achieve, especially without fragmentation. Herein, we compare the results of GPC-RI and LC-ESI-MS for the separation and characterization of intact 1 kDa dextran. Hydrophilic interaction chromatography is utilized to separate oligomers in a size dependent manner. Additionally, the enzymatic degradation of 40 kDa dextran by dextranase is studied by LC-MS at varying time intervals with different methods of denaturation. Size exclusion chromatography preformed to separate these oligomers before MS analysis. ESI offers advantages over other ionization techniques such as MALDI because it can be preformed online and coupled to a separation step. ESI is also considered a soft ionization technique, resulting in less fragmentation and sample destruction leading to ease in identifying of the native state of polymer.

75th Anniversary poster: LC-MS investigation of intact dextran and enzymatically degraded dextran

246th National Meeting (2013)

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