Validation of washing procedures for maintaining a microbiologically clean gel filtration column

Chromatographic gel filtration matrixes used in various separation techniques are subject to microbial contamination. The need for a microbe-free column is critical when preparing materials that require a low or zero microbial count. This report proposes two alternative washing systems: 0.02 N HCl containing 0.81% NaCl, and 0.1 M tromethamine--hydrochloride buffer (pH 7.0) containing 0.81% NaCl and 0.02% thimerosal. These washing systems were validated using a 100 x 2.6-cm column packed with a modified dextran gel slurry previously inoculated with known counts of USP test organisms. After each wash, the column separation characteristics were verified further with appropriate test proteins.