PURPOSE: To perform separation and elution by verying the temperature thereby verying the hydrophobicity or hydrophilicity using a temperature-sensitive polymer compound having a lower critical solution temperature(LCST).

CONSTITUTION: A sample is charged with a carrier composed of a temperature- sensitive polymer compound having a lower critical solution temperature and then the temperature is varied with time between levels above and below the LCST. The temperature may be varied from a level above the LCST to a level below the LCST or reversely. The temperature may be varied to pass the LCST and then varied again to pass the LCST. For example, a solute can be eluted by performing reverse phase chromatography at a temperature higher than LCST in order to hold the solute on the carrier through hydrophobic bond and then lowering the temperature below the LCST. This method requires no application of organic solvent at the time of elution. Since denaturation does not take place, this method is especially useful for separating a biological compound, e.g. protein.