HPLC separation of fullerenes on the stationary phases of two Lewis bases modified magnesia-zirconia

Spherical particles (6-8 μm) of magnesia-zirconia composite were prepared by means of sol-gel process. The composites were modified with 2,4,6-trinitrophenol and pyrenebutyric acid, respectively, and then used as charge-transfer stationary phases. The resulting stationary phases were characterized by elemental analysis, diffused reflectance FT-IR, nitrogen adsorption analysis and solid state NMR. The separation of C60, C70 and higher fullerenes was investigated on the two stationary phases. The influence of the mobile phase (toluene-cyclohexane) with different composition and the column temperature on the separation of C60 and C70 was examined, respectively. The retention time of C60 and C70 on the two stationary phases increases with decreasing toluene content in the mobile phase or with increasing the column temperature. Higher fullerenes can be separated well at 90 °C using toluene as the mobile phase on the 2,4,6-trinitrophenol modified magnesia-zirconia. Based on the results of column loading capacity test, the magnesia-zirconia modified with 2,4,6-trinitrophenol and pyrenebutyric acid are probably considered as potential materials for the separation of fullerenes in large amounts.