High temperature liquid chromatography of tocol-derivatives on polybutadiene-coated zirconia stationary phases

High temperature reversed-phase high performance liquid chromatography is evaluated as a new approach for the separation of vitamin E isomers (alpha-, gamma-, delta-tocopherol, and alpha-, gamma-, delta-tocotrienol) and alpha-tocopherol acetate. The separations of each analyte were examined by varying the eluent composition and column temperature. Using a polybutadiene-coated zirconia column at temperatures of 80 degrees C-140 degrees C, complete separations were achieved within 10-20 min using organic modifier (acetonitrile) in the range of 40-50%. Irregularity of the Van't Hoff analysis was noted over the temperature studied. The plot tends to deviate from linearity at higher operating temperatures (140 degrees C and 150 degrees C) with linear deviation errors of 12.7% and 41.6%, respectively, for the mobile phase examined.