Comparative Evaluation of Ultrafiltration Membranes for Purification of Synthetic Peptides

Abstract

Abstract Published information on the use of ultrafiltration to separate natural and synthetic peptides from each other, and from low-molecular-weight impurities, is reviewed. The suitability of commercial membranes of low nominal molecular weight cut-off (500-8000 daltons) for fractionation of synthetic peptides was evaluated with a model mixture of a hexapeptide (MW 844), insulin (MW 5730), and cytochrome c (MW 12,384) in 5% acetic acid. Diafiltration in a cross-flow thin-channel device allowed graphical determination of the retention coefficient for each solute on each membrane; fouling and cleanability were also assessed. Regenerated cellulose and cellulose acetate membranes did not foul, were chemically resistant, and fractionated efficiently. Other membrane types, including polysulfone and Teflon, fouled and were difficult to clean. Cellulosic membranes can be successfully integrated into the purification of synthetic peptides.