When the buffer eluent is acidic, four types of proteins are separated using IEC DEAE-825 (a column for weak anion exchange chromatography) well. In opposition to this, when the eluent is alkaline, the separation of the proteins is poor. By increasing the pH value, the four peaks tend to converge into one peak. The reason for that is the ion exchange groups of the packing material cannot dissociate adequately when the pH value is high.


Sample : 100 μL
1. Conalbumin 0.1 %
2. Transferrin 0.2 %
3. Ovalbumin 0.2 %
4. Trypsin inhibitor 0.2 %

Column       : Shodex IEC DEAE-825 (8.0 mm I.D. x 75 mm)
Eluent       : (A); 20 mM Piperazine-HCl buffer (pH6.0)
                    20 mM Bis-Tris-HCl buffer (pH7.0)
                    20 mM Tris-HCl buffer (pH8.0)
                    20 mM Ethanolamine-HCl buffer (pH9.0)
                    20 mM 1,3-Diaminopropane-HCl buffer (pH10.0)
               (B); (A) + 0.5 M NaCl
               Linear gradient: 0 min to 20 min, (A) to (B)
Flow rate    : 1.0 mL/min
Detector     : UV (280 nm)
Column temp. : 25 °C