Multimeric high-performance liquid chromatography of plant sterols using UV detection

A method for the multimeric high-performance liquid chromatography of plant sterols is proposed which permits the separation of compounds close in structure with similar chromatographic properties. The first stage includes the chemical modification of the sterols with the aid of a bis(p-nitrophenyl) phosphate group. The phosphotriesters formed as the result of the reaction are separated by normal-phase HPLC. The compounds isolated are treated with ammonia, as a result of which the sterol phosphotriesters are converted into the corresponding phosphodiesters. These phosphodiesters are then subjected to reversed-phase HPLC. The chromatographic separation of UV-absorbing sterol derivatives using several variants of HPLC substantially increases the resolving power of the method.