PROTEIN SEPARATION BY LIQUID-CHROMATOGRAPHY USING PERMEABLE POROS Q MPARTICLES/

Elution chromatography under non-retained conditions and frontal chrom atography in retained conditions using various proteins (bovine serum albumin, myoglobin and ovalbumin) and POROS Q/M large-pore particles ( PerSeptive Biosystems, Cambridge, MA, USA) were studied. Elution exper iments show that the mass transfer mechanism which allows improved per formance of perfusion chromatography is intraparticle convection. Conv ection enhances intraparticle diffusivity; the concept of ''augmented' ' effective diffusivity was used to explain both peak sharpening and t he modified Van Deemter equation for large-pore particles. Experimenta l adsorption isotherms were measured from experimental breakthrough cu rves. In the high concentration range (above 1 mg ml(-1)) the isotherm is rectangular; however, data in the low concentration region show th at the Langmuir equation better represents the whole isotherm. A simpl e fixed-bed model based on a rectangular adsorption isotherm was used in the simulation of breakthrough curves and augmented effective diffu sivities were calculated. The dependence of the augmented effective di ffusivity on the superficial velocity agrees well with the relationshi p derived by Rodrigues et al. (A.E. Rodrigues, B. Ahn and A. Zoulalian , AIChE J., 28 (1982) 541). Similar results were obtained by using the Langmuir isotherm in a more detailed modelling of the chromatographic column.