Heptane as a less toxic option than hexane for the separation of vitamin E from food products using normal phase HPLC

Abstract

The term ‘vitamin E’ refers to a group of eight vitamers (alpha-, beta-, gamma-, delta-tocopherols and tocotrienols). Its primary role is thought to be as an antioxidant commonly added to a variety of foods, e.g. bakery products. High-Performance Liquid Chromatography (HPLC) procedures are used for the separation and analysis of these tocopherols and tocotrienols in foods. The use of a normal phase column is the preferred approach in such methods, with hexane almost universally utilised as the mobile phase. However there is increasing concern regarding the toxicity of hexane. Here we evaluate the use of heptane as a replacement for hexane in HPLC based vitamin E analysis. The two solvents were compared using samples of bread fortified with palm oil (as a source of vitamin E). Accelerated solvent extraction procedure followed by HPLC showed the effective separation of the E vitamers in a variety of bread samples using both solvents. It is concluded that heptane provides effective separation and quantification of the E vitamers found in cereals and cereal products while also reducing operator risk.