Liquid-gel chromatography on lipophilic-hydrophobic Sephadex derivatives

Hydrophobic long-chain alkyl ethers of Sephadex have been synthesized and tested for use in liquid chromatography. With columns prepared in such polar solvents as methanol, reversed-phase systems are obtained where compounds separate in order of decreasing polarity. In such non-polar solvents as heptane, straight-phase systems are formed, and separations occur in order of increasing polarity. The retention volume of a compound is determined mainly by its polarity, the type and degree of substitution of Sephadex, and the nature of the solvent system. Examples are given of straight-and reversed-phase separations of waxes, fatty acids, glycerides, glycerol ethers, sterols, bile acids, and hormonal steroids. The Sephadex derivatives are simple to make, the columns are easy to prepare, and they can be used over long periods of time. Liquid-gel chromatography on alkyl ethers of Sephadex is a mild separation technique and should be a useful complement to other chromatographic methods.