Optimization of parameters of chromatographic separation of diphenylpolyenes mixtures

Abstract

TLC and HPLC methods have been employed to study the interaction of diphenylpolyenes with
SiO2 and SiO2–C18 in organic and aqueous media. Electronic absorption spectra of diphenylpolyenes have
been measured in different solvents, and optimal conditions for UV detection of polyenes have been revealed.
The mixtures of n-hexane – ethyl acetate and water – acetonitrile were used as the solvents in normal
and reversed-phase TLC and HPLC. The retention constants of diphenylpolyenes have been revealed to depend
on the geometry and configuration of their molecules, the length of an olefin fragment, and the nature
and polarity of an eluent. The interaction of diphenylpolyenes with SiO2 surface in a binary organic solvent
and with SiO2-C18 surface in a water–organic solvent has been shown to intensify in the series cis-1,2-
diphenylethylene < trans-1,2-diphenylethylene < trans-1,4-diphenyl-1,3-butadiene < trans-1,6-diphenyl1,3,5-hexatriene
< β-carotene. It has been shown that, under the conditions of normal and reversed-phase
TLC and HPLC, a rise in the fraction of ethyl acetate in n-hexane and acetonitrile in water, respectively,
weakens the retention of diphenylpolyenes. The numerical values of the coefficients obtained can be used to
optimize conditions for the practical separation of mixtures of plant extracts of diphenylpolyenes and mixtures
of products of chemical synthesis.