Ultrahigh Pressure Liquid Chromatographic Determination of Tocopherols in B100 Biodiesel

A reversed-phase gradient ultrahigh pressure liquid chromatographic method with a water–acetonitrile mobile phase and UV detection has been developed to rapidly determine the concentration of the major tocopherol components in B100. The described method requires minimal sample preparation and provides short analysis times compatible with the needs of small to mid-size laboratories involved in B100 analyses. The objectives of this work were twofold. We wished to develop an analytical method both to rapidly screen B100 samples for their tocopherol content and to provide additional information on the source (from the distribution of tocopherols) and the nature of the processing of the B100 (absence of tocopherols would suggest distillation). Information on the tocopherol content of the B100 can be used to assess the inherent antioxidant content of the B100 and the extent to which additional stabilizers are required. The method determines the concentration of alpha, gamma and delta tocopherols and has a chromatographic run time of 4.5 min with minimal sample preparation. Calibration curves were linear over the range of 5–350 μg/mL and had correlation coefficients exceeding 0.999. The short term precision of the method was evaluated, and relative standard deviations were typically 2 % or less. Recovery of spiked tocopherols averaged 97 %.