By Anonymous on Saturday, September 13, 2003 - 03:44 am:
i am new to normal phase method development i would like to know what kind of buffer and mobile phase additatives we can use in normal phase hplc .
By Anonymous on Saturday, September 13, 2003 - 03:29 pm:
Any buffer that is soluble in hexane will do.
By Mokhtar on Sunday, September 14, 2003 - 02:08 am:
in normal phase chromatography you will not use buffer , you will use a mobile phase composed from,:- nonpolar organic solvent such as hexane and a relatively more polar organic solvent such as acetonitrile, CHCl3,CH2Cl2 or THF.retention will increase with the ratio of nonpolar solvent(hexane) increase.
Avoid introduction of buffer or water into mobile phase( immescibility, and silica deterioration occurs)
By alex on Sunday, September 14, 2003 - 11:03 pm:
Hi,
search a paper from Snyder "Properties of solvents" or something similar from 1974 i think. He lists the properties and gives some information beyond simple polarity / elutropic row thinking.
Or use a textbook on HPLC. Or look into column vendors application notes: normal phase applications are the ones on underivatized silica or diol columns or amino columns.
Analytical NP chromatography uses all kinds of solvents and mixtures (even with water).
When I did preparative NPC solvent mixtures were heptan/chloroform and ethyl acetate / methanol