Abstract: The Zvalue of the stoichiometric displacement model for retention can be used to be a new chracterization parameter for the molecular conformation of biopolymers caused by temperature in reversed-phase liquid chromatography(RPLC).It was found that when 2-propanol 44%(V/V)-formic acid-water was selected as a mobile phase, the Zvalues of four kinds of completely denaturated proteins decreased with the increase of temperature and the Zvalue changes would be directly proportional to the reciprocal of absolute termperature (1/T).The chracterization of the change in the molecular conformation of biopolymers in the instance can be obtained by means of the difference between the two slopes of each proteins from the plots of Zvs. 1/T, and the larger the difference, the greater the change in the molecular conformation of the protein is. The abrupt change temperatures for each proteins can be calculated from the intersect of the two straight lines. Compared to the characterization of molecular conformation of proteins with the plot of 1gk'(k'is the capacity factor)versus 1/T, the plot Zversus 1/Tis not only valid for each type of proteins, but also is more accurate.

Key words: Liquid chromatography, Protein, Molecular conformation, Thermal denaturation