Key words: supercritical fluid chromatography, furocoumarin, methoxypsoralen, retention mechanisms
A method for separation of isomeric psoralen methoxy-derivatives, namely bergapten, xanthotoxin and isopimpinellin, is developed. The results of sorbent screening allow one to consider a normal phase elution regime as optimal for separation of these compounds in SFC. The analysis of methoxypsoralen (MOP) retention mechanisms showed that the same one is responsible for MOP’s separation on all tested silica sorbents containing polar groups, except 2-ethylpyridine and pentafluorophenyl. A possible explanation of the observed MOP’s retention phenomena is given. In the case of pentafluorophenyl sorbent π-electron intermolecular interactions play a key role in separation of closely related MOPs. It is likely that the same effects are responsible for a specific order of MOP’s elution observed when 2-ethylpyridine sorbent is used.
doi:10.1134/S1990793113080083