abstract |
Provided is a guard column including a filling part having a length of 2.0 cm to 3.5 cm formed of a filler, in which the filler is made of porous silica gel having a hydrophilized surface and an average particle size of 1.5 μm to 2.5 μm, and a pressure difference when an aqueous solution is fed at a linear flow rate of 2.1 cm/min is 4.0 MPa or more. |