View stationary phase specifications
View chemical structures of analytes
Click here to view
printable Application Sheet
Discussion of Chromatograms:
Chromatogram A shows the retention of Loratadine in organic, normal phase in conditions where Carvone would
be on the solvent front, and not retained at all.
Chromatogram B shows the retention of Carvone in organic, normal phase in conditions where Loratadine would
be infinitely retained on the column.
Chromatogram C shows the retention and elution of Carvone in organic, normal phase in approximately one
minute. Then due to the flexible nature of the Cogent Bidentate C18™ column, a quick “step gradient” or change
of mobile phase concentration produces conditions that allow Loratadine to elute in five minutes in the same run,
on the same column. Peak shape could be further optimized but was outside of the scope this application note.
|
Method Conditions
| Mobile Phase |
A: Hexane, B: THF |
| Column |
Cogent Bidentate C18™ |
| Catalog Number |
40018-7.5 |
| Dimensions |
75mm x 4.6mm ID |
| Flow Rate |
1ml/minute |
| Detection |
UV 255nm |
Implications, Advantages and Uses:
Two compounds with similar polarity that can be resolved isocratically in reverse phase conditions are
infinitely more separated on this column in normal phase conditions; without the characteristic hassles
associated with silica and other “normal phase” columns that makes changing from NP to RP and back very
easy. The separation shown in Chromatogram C offers the chromatographer capacity to load much more onto
the column and therefore use, a 250mm x 4.6mm ID column to “Prep Up” these compounds that have similar
polarity but different functionality. The ability to “Prep Up” and check purity on the same Cogent
Bidentate C18™ column offers time savings and ease of use and improved Normal Phase Chromatography.
|
