PROBLEM TO BE SOLVED: To stably separate and split a biological sample by a small volume. SOLUTION: A biological sample separation method to separate and split a biological sample, includes the steps of adsorbing a biological sample containing protein to a first reversed phase column, eluting components other than main protein from the first reversed column with an organic solvent, diluting the eluted sample with water to lower an organic solvent concentration thereof, introducing the eluted sample from the first column to a second reversed phase column thinner than the first column, and eluting the sample at a flow rate lower than that when eluted from the first column. COPYRIGHT: (C)2010,JPO&INPIT
