Determination of tocopherol contents in refined edible oils using an HPLC method

Abstract

A high-performance liquid chromatography method was applied to determine the contents of tocopherols in edible oils using a LiChrosorb DIOL HPLC column and hexane fortified with 0.1% acetic acid in an isocratic mode. The validation of the method included tests for linearity, sensitivity, accuracy, precision, and recovery. All calibration curves showed good linear regression (r 2>0.9995) within the tested ranges. The established method offered good precision and accuracy with overall intra-day and inter-day variations of 0.94∼4.27 and 1.77∼4.88%, respectively. The tocopherol recoveries ranged from 91.44∼108.90%. Subsequently, the method was successfully applied to qualitatively and quantitatively determine the total contents of α, γ, and δ-tocopherols in 12 selected refined edible oils, showing a range of 0.92 to 188.71 mg/100 g.