2017 Volume 38 Issue 2 Pages 45-51
In this report, C70-fullerene (C70), which has aspheric structure and greater π electrons compared to C60-fullerene (C60), was effectively immobilized onto the surface of a silica-monolithic capillary, and then the retention characteristics for polycyclic aromatic hydrocarbons (PAHs) due to π-π interaction were evaluated in liquid chromatography (LC). For the immobilization of C70, a C70 derivative via thermal reactive agent, perfluorophenylazide (PFPA) and N-hydroxysuccinimide (NHS) was synthesized. In comparison with a typical thermal reaction in an oil bath and a microwave, the latter reaction provided higher yield. Then, both the C70 and C60 monoliths were evaluated by LC with a variety of PAHs as the solutes. The results suggested that the specific interactions, such as dipole and induced dipole interactions were contributed between the bonded C70 and PAHs. Absorption spectra of PAHs with C60 or C70 and a computer simulation also supported these interactions. Furthermore, the comparison of the separations for PAHs and brominated benzenes with the C70 column and a porous graphite carbon packed column suggested that the interactions based on the polarization of the molecules contributed the separations.