I would like to know what methodologies exist for LC analyses of cholesterol and cholesterol derivatives exists. I assume it must be a normal-phase procedures, but any information will be helpful. Thanks so much

Val

Cholesterol itself can also be analyzed with the mobile phase acetonitrile-isopropanol 95:5 on a short C18 column (Spherisorb ODS1 50x4.6 mm ID, 3 µm particles) with UV detection at 200 nm or, better, with ELSD detection.
Reference: J. Med. Chem. 42 (1999) 1306
For cholesterol derivatives (which?) you might try these conditions as a start.

Analysis of cholesterol by LC can be problematic. The molecule has only a single isolated double bond and therefore UV detection is rather insensitive and as the above message suggests, Lambda max is at very low UV wavelength where many impurities may also absorb. Refractive index detection works but suffers from all the usual problems of this method (low sensitivity, difficulties if using gradient elution etc).

Why not do the analysis by (capillary) GC? This is generally very simple- most people use non-polar methylsilicone, or slightly polar methylphenylsilicone phases and prepare trimethylsilyl derivatives which tend to give better peak shapes and quantitation. You will have no trouble achieving detection limits of 1 ng or better and the column efficiencies may be up to an order of magnitude higher than HPLC.

David McCalley

You might consider Light scattering detectors.

I would like to know what methodologies exist for LC analyses of DMPG (1,2-Dimyristoyl-sn-Glycerol-3-(Phospho-rac-(1-Glycerol))and its derivatives exists. I assume it must be a normal-phase procedures, but any information will be helpful. Thanks so much