Supercritical fluid chromatographic determination of cholesterol and cholesteryl esters in serum on ODS-silica gel column

Enzymatic assay of cholesterol by reaction rate measurements

A dynamic method for free and total cholesterol assay based on the oxidation of cholesterol by cholesterol oxidase, and conversion of cholesteryl oleate to cholesterol by cholesterol esterase is discussed in this article. The reaction conditions for total cholesterol assay were a temperature of 310 K and pH of 7.4. For conversion of cholesteryl oleate to cholesterol, the samples were incubated with 0.6 unit/mL of cholesterol esterase and 0.02 g/mL of taurocholate. The determination of initial reaction rates in the oxidation of free cholesterol, which is directly related to the cholesterol concentration, was found to be rapid, reliable, and inexpensive. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 53: 391-396, 1997.

Analysis of non-saponifiable lipids by super-/subcritical-fluid chromatography

Because of the particular properties of carbon dioxide or carbon dioxide/modifier mobile phases, super- or subcritical-fluid chromatography (SFC) can be an alternative to more classical chromatographic methods such as gas chromatography (GC) or high-performance liquid chromatography (HPLC) for the separation of unsaponifiable lipids. These fluids can also be helpful in the extraction and/or the concentration steps of sterols, tocopherols or carotenoids from complex samples. Supercritical extraction, off-line prefractionation or semi-preparative supercritical fluid chromatography, carried out before the analysis are described. The effects on separation of analytical parameters such as pressure, nature of and modifier percentage or stationary phase nature are also reported. The performance of capillary, packed or capillary packed columns is discussed, as well as the consequences of their use (choice of stationary phases, type of coupled detector). Numerous examples of fine separations are reported.

Chromatographic methods in the analysis of cholesterol and related lipids

Methods using thin-layer chromatography, solid-phase extraction, gas chromatography, high-performance liquid chromatography and supercritical fluid chromatography are described for the analysis of single cholesterol, esterified and sulfated cholesterol, and for cholesterol in the context of other lipid components, like other sterols and lipid classes. In connection with these techniques several clinical applications are mentioned.