Comparison of porous silica packing materials for preparative ion-exchange chromatography

Although analytical high-performance liquid chromatographic columns have been successfully used for purification of milligram amounts of proteins, they do not appear to be ideal for preparing gram or kilogram quantities because of cost and load capacities. In this paper the development of preparative weak anion-exchange materials is described. These materials possess similar chromatographic characteristics to analytical 5-10 micron materials, yet also have high load capacities. A number of inorganic packings were examined to determine which had the best combination of high load capacity, good resolution, stability, and low cost. When appropriate flow-rates and gradient shapes were used, 30-50 micron materials produced resolution of components of a commercial ovalbumin sample that was comparable to that achieved on a 6-micron material. An amount of 3 g of a protein could be loaded onto a 250 X 21 mm-I.D. column with adequate resolution to separate it from some of its impurities.