Page 126 - Applied Pharmacognosy

Mobile Phase Selection

Normal Phase Reversed Phase

❑ St. Phase: Silica gel: -Si-OH. ❑ St. Phase: Octadecyl

❑ Mobile Phase; Basic solvent: C18-bonded silica gel
➢ Hydrocarbons, e.g. hexane, (ODS) (Non-polar).
Polarity increases
benzene. ❑ Mobile Phase; Water,

➢ Organochlorides, e.g. chloroform, methanol, acetonitrile.

dichloromethane. Revise Normal Phase
❑ Mobile Phase; Additive solvent: adsorption separation from

➢ Alcohols, e.g. ethanol, methanol. chromatography
➢ Ethers, e.g. diethyl ether. introduction in these
➢ Ethyl acetate, acetonitrile, acetone.
handouts

125