Melamine-formaldehyde resin were analyzed using Asahipak GS-310 7G. In some cases, a mixture of two solvents, with different hydrophobicities, is used as an eluent. When the structure or the characteristics of the sample are complicated, it is useful to use such mixed-solvent eluent. Melamine-formaldehyde resin is analyzed by using a chloroform/methanol eluent. The sample interacts with the packing material, when an eluent such as just chloroform or methanol is used. Therefore, this sample cannot be eluted by GPC mode. When a chloroform/methanol(80/20) eluent is used, however, the interaction disappears and the elution by GPC mode can take place. GS-310 7G is an old type of GF-310 HQ.