The thermodynamic behaviors for some proteins and small molecules in h
ydrophobic interaction chromatography are studied in the temperature r
ange of 21 similar to 80 degrees C. The thermodynamic parameters (Delt
a H degrees, Delta S degrees, Delta G degrees) of these proteins are d
etermined by using Van't Hoff relationship (lnk'- 1/T). By using the o
btained standard entropy change (Delta S degrees) and free energy chan
ge (Delta G degrees), the conformational change of the proteins is jud
ged in chromatographic process. The linear relationships between Delta
H degrees and Delta S degrees can be used to evaluate ''compensation
temperature'' (beta) at the protein denaturation and identify the iden
tity of the protein retention mechanism in hydrophobic interaction chr
omatography.