A sample of different proteins and peptides was separated with various pH values of the eluent. Under acidic conditions (pH2.3, pH3.0), Leu-Enkephalin and Leu-Trp-Met have been strongly retained and the elution times for the substances are quite similar; therefore, the separation is not satisfactory. In contrast, when an alkaline according to the fact that, under alkaline condition (pH10) with Asahipak ODP column, a better separation with sharper peaks of the substances has been obtained in a shorter time. In addition, ODP columns have higher theoretical plate numbers under alkaline conditions.
Refer to Analysis of Oligopeptides with Acidic and Alkaline Eluent.
|Theoretical plate number|
Column : Shodex Asahipak ODP-50 6D (6.0mmI.D. x 150mm) Eluent : buffer/CH3CN=85/15 (pH2.3) 0.05% TFA aq. (pH3.0) 50mM Acetic acid aq. (pH6.7) 50mM Ammonium acetare buffer (pH10.0) 50mM Ammonium acetare buffer Flow rate : 1.0mL/min Detector : UV(220nm) Column temp. : 30°C