The base packing material of the IEC DEAE-825 (a column for weak anion exchange chromatography) is poly(hydroxy methacrylate) and that of the Asahipak ES-502N 7C (a column for weak anion exchange chromatography) is poly(vinyl alcohol). In case of poly(vinyl alcohol) material, not only the ion exchange mode affect the separation, but also the reversed phase mode contributes to some degree to the separation of high molecular weight compounds such as proteins. There are some cases in which the difference in the packing material base may affect the separation.