No.6 Tips on using Polyamine II in the ion exchange mode.

YMC-Pack Polymine II is highly effective in separation of saccharides including oligosaccharides and is employed in normal phase separation with nonaqueous eluent or in separation of ionic compounds by combining normal phase and weak anion exchange mode.

In the example of analysis of ascorbic acid depicted below, anions in the eluent and amino groups on the surfaces of support material are in a state in which ion-pairs are formed. If the ion-pairing has not yet reached ionic equilibrium, retention times of a sample might alter. We recommend that to avoid this problem by facilitating ion-pairing, the operation as described below be conducted before starting analysis.

Column equilibration in ascorbic acid analysis (in the case the column size 250 X 4.6mm I.D.)

1. Flush the columin with water at the flow rate of 1.0 mL/min for 10 minutes.
2. Flush the column with 200mM of water solution of ammonium dihydrogen phosphate at the flow rate of 1.0mL/min for 40 minutes.
3. Flush the column with water at the flow rate of 1.0mL/min for 30 minutes.
4. Flush the column with the eluent for analytical use at the flow rate of 1.0mL/min for 60 minutes.

After using these eluents, sugar analysis using acetonitrile/water eluents might cause anomalies in peak shapes (such as doubling or broadening). Considering the life time or separation reproducibility, it is desirable that separate columns be respectively used for each eluent.