Novel simulated moving-bed method for reduced solvent consumption

Simulated moving-bed (SMB) chromatography is attractive for reducing sorben t and solvent consumption relative to fixed-bed systems. In this contributi on, we describe a novel and versatile method for further reducing solvent c onsumption in the case of reversed-phase chromatography. The method is base d on the variation of the distribution coefficients of solutes to be separa ted upon varying the composition of a multi-component mobile phase. If the solvent strength of the desorbent is set higher than the solvent strength o f the feed, the components will have smaller distribution coefficients in t he extraction section of the SMS and hence will be more easily eluted. This will result in a lower desorbent flow and possibly also in a shorter desor bent zone, and, ultimately, in more concentrated products. The so-called "T riangle-method" by Storti et al. [AIChE J., 39 (1993) 471] to obtain the re gion of complete separation, is extended for this novel SMB method. Theoret ical evaluation of the proposed methodology supports the anticipated solven t reduction relative to fixed-bed RP-HPLC for the cases of the purification of the polyketide antibiotic nystatin and the separation of bovine insulin from porcine insulin. (C) 2000 Elsevier Science B.V. All rights reserved.