Synthesis and characterization of extended length alkyl stationary phases for liquid chromatography with application to the separation of carotenoid isomers

A new, long-chain (similar to C-34) alkyl-bonded stationary phase for liquid chromatography (LC) was synthesized and utilized for the separation of carotenoid mixtures. This stationary phase exhibited increased selectivity for certain cis isomers of alpha- and beta-carotene as compared to the recently reported C-30 stationary phase. The new stationary phase was synthesized using two bonding strategies: traditional polymeric synthesis and a surface-polymerization synthesis, with the latter yielding columns with improved resolution for carotenoids. A natural extract with a high degree of cis isomerization was well separated with this long-chain stationary phase.