VISCOUS FINGERING IN SIZE-EXCLUSION CHROMATOGRAPHY - INSIGHTS FROM NUMERICAL-SIMULATION

A two-dimensional hybrid finite difference/particle-tracking simulatio n has been used to study the now nonuniformities induced by the viscou s fingering instability during size exclusion chromatography of protei ns. The numerical simulation faithfully reproduces the morphology and dynamics of viscous fingering observed in magnetic resonance images of sample migration through operating chromatography columns. In additio n to sample intrinsic viscosity, solute molecular diffusivity and pack ing heterogeneities are found to have a significant impact on finger d ynamics. More so than in chromatography of solutes which do not enhanc e viscosity, packing heterogeneities lead to considerable increases in HETP for viscous samples. Where intraparticle mass transfer resistanc es are small, the effect of fingering on HETP is almost independent of velocity.