Reversed phase chromatography / Open colomun chromatography
Open column chromatography is an excellent and easy technique for large scale preparation and purification at low cost. Reversed phase C18 packing materials are used but restricted to about 30-50% water in the mobile phase. The COSMOSIL C18-OPN is a new "Water-Wet" C18 packing material developed for Reversed Phase Open Column Chromatography. The C18-OPN material can be used in 100% aqueous eluents.
C18 packing materials in 100% water Normal C18 materials float on water
The external surface of the C18-OPN gel is coated with hydrophilic groups.
|Effect of particle size|
|Particle (um)||Flow rate (ml/min)||Theoretical plate number||Rs||Separation time(min)||Consumption of solvent (ml)|
In reversed phase chromatography, hydrophilic compounds such as Theobromine and Theophylline could be separated under low concentration of organic solvent. The figure shows they are clearly separated by reversed open column chromatography with 70% of water.
Since the structural difference between p-Cresol and p-Ethylphenol is only one methyene group. It is difficult to separate such samples under normal phase condition. On the other hand, the samples are clearly separated under reversed phase condition with COSMOSIL C18-OPN packing material.