Ernst Nyström

SEPARATION OF LIPIDS ON METHYLATED SEPHADEX.

Abstract Methylated Sephadex G-25 and G-50 have been prepared. These materials are useful for the separation of lipid-soluble compounds. The separation of phospholipids, triglycerides, cholesterol esters, cholesterol, fatty acids, bile acids, and some polymers has been studied. The separations appear to be based partly on differences in size and/or shape of the molecules and partly on liquid-liquid partition between a mobile phase and a stationary gel-solvent phase. By choosing different solvent mixtures, liquid-liquid partition chromatography of either the reversed-phase or the “straight”-phase type can be obtained. It is probable that absorption of polar compounds to the gel network can occur in certain solvents.

Preparation of lipophilic anion exchangers from chlorohydroxypropylated sephadex and cellulose

Abstract Chlorohydroxypropyl derivatives of Sephadex and cellulose were reacted with ammonia and primary, secondary or tertiary amines to prepare a wide range of lipophilic anion exchangers. These can be used for chromatography in organic solvents, exemplified by the separation of a phospholipid mixture using a dibutylaminohydroxypropyl derivative of Sephadex LH-20.

Quantification of cholesteryl sulfate and neutral sterol derivatives in human feces after purification on lipophilic sephadex gels: Bile acids and steroids 188

Abstract The sterol sulfate fraction in human feces has been analyzed by an isotope dilution technique. In the four subjects studied, 14 to 85 mg of cholesteryl sulfate were found in a one day portion of feces. This corresponded to 2.2–3.9% of the total cholesterol output. In contrast, pronounced variations between the subjects were found upon analysis of the neutral fecal cholesterol metabolites.

Sterol composition of the steryl sulfate fraction in human feces: Bile acids and steroids 196

Abstract Cholesterol, cholestanol, lathosterol, campesterol, campestanol, stigmasterol, β-sitosterol and β-sitostanol, have been identified in the steryl sulfate fraction from feces of healthy subjects on a free diet. Evidence was also obtained for the presence of brassicasterol and fu-costerol. No 3β-hydroxy-5β-sterols could be found. The amount of cholesteryl sulfate was estimated to at least 85% of the entire steryl sulfate fraction.

Reversed-phase chromatography of fatty acids on hydrophobic sephadex

Abstract A number of solvent systems are given for use in liquid-gel chromatography with hydrophobic Sephadex. Since the solvents contain both polar components with a low affinity to the gel and less polar components with a higher affinity to the gel, a chromatographic system will be obtained which is similar to reversed-phase partition. Examples are given of separations of free fatty acids and fatty acid methyl esters. The influence of particle size, flow rate, and temperature is discussed.