YMC-Pack ODS-AL uses not only hydrophobic interaction but also secondary interactions with reactive residual silanol groups to affect separation. This results in a different selectivity from conventional ODS columns. When ionic interactions are involved, it is preferable to use a buffer in the mobile phase to achieve reproducibility of chromatograms.
 |
1. Uracil
2. Pyridine
3. 2,6-diemetylpyridine
4. Methylparaben |
Effects of silanol groups
The separation factor (α) of internal standards methylparaben/2,6-dimethylpyridine for ODS-AM is different to that of ODS-AL, which is not endcapped. ODS-AL, which contains residual silanol groups, shows relatively great retention of pyridines.
 |
Column : YMC-Pack ODS-AL and ODS-AQ (5µm, 12nm)
150 x 4.6mm ID
Eluent : 100mM KH2PO4 – Na2HPO4 (pH 7.0) /methanol (75/25)
Flow rate : 0.8 ml/min
Temperature : 30°C
Detection : UV at 270nm
(Condition described in Japanese Pharmacopoeia 12th ed.) |
Utilises residual silanol groups for separation
The figure above shows separation of microbiocides under the conditions described in the Japaneses Pharmacopeia. The object is to select the column which allows the elution of benzoic acid, salicylic acid and theophylline, in this order, with complete separation of these peaks. With ODS-AQ, separation of salicylic acid and theophylline is incomplete. By contrast ODS-AL provides excellent separation. Therefore ODS-AL may provide excellent separation when the separation conditions cannot be optimised on other ODS columns.
Column care
YMC-Pack ODS-AL is stable towards hydrolysis between pH 2-7,5. Remove acid and buffer salts before storage. Store the column in methanol / water = 70/30.
For detailed information please refer to the “Column Care and Use Instructions” which are shipped with each analytical column.
|
Start
