SILICA DEXTRAN SORBENT COMPOSITES AND THEIR CLEANING IN PLACE

Large-scale liquid chromatography requires sorbents that are mechanically stable in order to ensure repeated cycles without shrinkage. The industrial separation of biological materials moreover implies working in apyrogenic and sterile conditions. Dextran-coated silica used as a chromatographic sorbent was treated with different sanitizing solutions after bacterial contamination. It was demonstrated that most of the strains used were inactivated by using alkaline solutions or ethanolic acetic acid. However, the sporulated form of Bacillus subtilis, which seemed more resistant than other strains, was inactivated only when alkaline solutions contained more than 40% ethanol. All these treatments were also very effective for pyrogen removal and did not indicate significant degradation of the silica moiety or the chromatographic performance of the sorbent.