Azeotropic phenomena during separation of dilute mixtures of proteins by simulated moving bed chromatography

Recently, we have introduced the use of a salt gradient over a simulated mo ving bed system used for purification of proteins using ion exchange chroma tography. This paper describes azeotropic phenomena in such a system, where complete separation of mixtures of proteins is not possible at certain sal t concentrations, due to a reversing selectivity. These phenomena impose ad ditional restrictions on the selection of the flow rates in each of the sec tions of the simulated moving bed which are discussed. (C) 1999 Society of Chemical Industry.