Altering efficiency of hydrophobic interaction chromatography by combined salt and temperature effects

The coupled effect of salt concentration and temperature on the retention behavior of proteins in hydrophobic interaction chromatography has been studied. The retention data of four model proteins, i.e., myoglobin, lysozyme, α-chymotrypsinogen and bovine serum albumin, have been acquired by isocratic experiments of chromatographic elution within the temperature range 5–25 °C at different ammonium sulphate concentrations in the mobile phase. The retention dependencies quantified as functions of the salt concentration and temperature have been exploited in designing the process of gradient elution. The propagation velocity of proteins under conditions of the step gradient of salt and temperature has been determined by use of the equilibrium theory. To evaluate kinetic effects accompanying the band propagation the transport-dispersive model has been employed. It has been shown that altering the propagation of the salt and temperature waves in a proper manner allows improving the separation efficiency. Moreover, manipulation of specific kinetics effects can also be exploited in protein separations.