Study On Determination Vitamin E In Vegetable Oil By Reversed-phase Liquid Chromatography

Vitamin E, also known as tocopherol, is classified into two categories, based on their chemical structures, tocopherol and tocotrienols. Each category can also be classified intoα-,β-,γ-andδ-, four different forms, based on the different number and location of methyl. Due to its unique chemical structure and properties, Vitamin E plays a very important role in human physiological health. Vegetable oil contains abundant natural Vitamin E, which is a good resource to produce natural Vitamin E. In this thesis, high performance liquid chromatography (HPLC) was selected as a detection instrument, with Reversed-Phase HPLC, to optimize the chromatographic conditions of detecting Vitamin E. The camellia seed oil, rarely studied, was used as subject to study the pre-tretment conditions of detecting its Vitamin E in samples, with the confirmed optimum chromatographic conditions and sample processing to determine the content of Vitamin E in several kinds of oil. The main conclusions of the studies are as follows:1. By a factorial and orthogonal experimental design, the optimum chromatographic conditions determined by Reversed-Phase HPLC are:detection wavelength:294 nm, mobile phase:methanol, flow:0.9ml/mi, and; column temperature:40℃.2. After the detection of purified tocopherol with multi-concentrations in a, y and 8 three forms, the linear correlation coefficients are respectively:a:R=0.9992, y: R=0.9984, and 6:R=0.9985.3. With optimizing the pre-process of vegetable oil samples, the optimum pre-treatment is determined:adding 10mL hexane into a tube filled 5.0 g vegetable oil, mixed evenly then followed by 30min ultrasonic oscillation extraction, removing the liquid to a brown volumetric flask of 50mL, diluted to the mark with hexane then shaking, filtering the liquid with 0.45μm microporous menbrane before determination. With this process, the recovery rate of VE is 102%4. After detecting Vitamin E respectively in camellia seed oil produced by both cold press and aqueous enzymatic methods, and in raw rapeseed oil and refined rapeseed oil, the finding is:less loss of Vitamin E in oil produced by cold press, and more loss of Vitamin E in the refinement procedure of oils.