Separation of individual tocopherols from soybean distillate by low pressure column chromatography

alpha-Tocopherol, gamma-tocopherol and delta-tocopherol were successfully separated and purified from soybean vitamin E concentrate (53% purity, from soybean oil deodorizer distillate) using a low-pressure glass column (500 mm x 25 mm, I.D., packed with silica gel). The effects of eluent, flow-rate and sample loading on separation efficiency were investigated using product purity and recovery as evaluation indices. On the basis of the single factor experiment results, an orthogonal test was designed to optimize the chromatographic separation conditions. The optimum conditions obtained by using analyses of extreme difference and variance are as follows: cyclohexane-ethanol 99.7:0.3 (v/v), flow-rate at 25 ml/min and loading amount being 2 ml (concentration 1 g/ml). Under these optimum conditions, purity of the alpha-tocopherol, gamma-tocopherol and delta-tocopherol were 92.35, 91.23, 89.95%, respectively; the recovery of those products were 35.21, 36.25, 61.25%, respectively. The advantage of this process is that high purity individual tocopherols can be obtained directly from soybean vitamin E concentrate at 53% purity, without additional purification steps.