Selectivity of long chain stationary phases in reversed phase liquid chromatography

A series of commercial monomeric and polymeric C18, C27, and C30 stationary phases were compared with immobilized poly(ethylene-co-acrylic acid) stationary phases synthesized in-house. The columns were characterized on the basis of methylene selectivity, silanol activity, metal activity, pore size, shape selectivity, and the ability to separate tocopherol isomers and carotenoid isomers. Monomeric and polymeric C30 phases were shown to yield excellent separations of the tocopherol isomers while the polymeric C30 and polyethylene phases were more appropriate to the separation of carotenoids.