The temperature convergence of biopolymers in reversed-phase liquid chromatography

Summary Based on a stoichiometric displacement model for retention (SDM-R) in liquid chromatography, the two linear plots, log/(a constant relating to the affinity of one mole of solute to the stationary phase) andZ (the total moles of the displacing agent released at the interface between stationary phase and solute molecules as one mole of the solute is absorbed by the stationary phase) of small solutes and biopolymers versus the reciprocal of absolute temperature, l/T, in reversed-phase liquid chromatography were theoretically derived and experimentally proved to be linear and to have a common point called the temperature convergent point. The two linear plots could be used instead of the plot of logk to l/T which is normally only valid for small solutes but not for biopolymers for investigations of chromatographic thermodynamics and temperature convergence. The average convergence temperature (T _conv) of biopolymers was theoretically derived to equal the ratio between the slope and the intercept from either one of the two linear plots and to be 130.8±9.3°C for five proteins which are very close to those of biopolymers by calorimetry. A new methodology to investigate chromatographic thermodynamics and possibly for investigating the temperature convergence of biopolymers in the process of protein folding is also presented.