Journal of Chromatography A, 881 (2000) 251–254 www.elsevier.com / locate / chroma Rapid determination of vitamin E in vegetable oils by reversed- phase high-performance liquid chromatography ´ E. Gimeno, A.I. Castellote, R.M. Lamuela-Raventos, M.C. de la Torre, * ´ M.C. Lopez-Sabater ´ ` ` Dpt. Nutricio i Bromatologia, Centre de Referencia en Tecnologia dels Aliments ( CeRTA), Facultat de Farmacia, Universitat de Barcelona, Avda. Joan XXIII s / n, 08028 Barcelona, Spain Abstract A quick and direct method for measuring tocopherols ( a, b1g and d) in vegetable oils has been developed using RP-HPLC with UV detection. Previous extraction of tocopherols is not required. The oil is diluted in hexane and an aliquot is mixed with ethanol containing an internal standard ( a-tocopherol acetate). The chromatographic system consists of an ODS-2 column with a methanol–water mobile phase. Tocopherols are detected at 292 nm in less than 5 min after injection. The method is precise (RSD52.69%) and has a high mean recovery (98.14%).  2000 Elsevier Science B.V. All rights reserved. Keywords: Oils; Food analysis; Vitamins; Tocopherols 1. Introduction implies multiple solvent extraction, drying and con- centration steps. Tocopherols are sensitive to light Vegetable oils are the main dietary sources of and air. Thus, procedures requiring many manipula- vitamin E, which decreases the risk of cardiovascular tions can result in the partial degradation of these diseases and cancer [1]. Vitamin E is a collective antioxidants and in considerable quantification errors term for tocopherols and tocotrienols, which are [9]. On the other hand, long exposure to alkaline natural antioxidants that prevent the rancidity of oils conditions significantly decreases a-tocopherol during storage and thus delay its shelf-life [2–4]. [7,10]. Therefore, sample preparation is the key step Whereas a-tocopherol (5,7,8-trimethyltocol) is the of the analysis. For these reason, in order to measure most active form of vitamin E in vivo, g-tocopherol tocopherols, some studies have performed direct (7,8-dimethyltocol) is the most active in vitro [5–7]. analysis after only diluting the oil in an organic Several reversed-phase high-performance liquid solvent, but normal-phase (NP) HPLC was used chromatography (RP-HPLC) studies for the determi- [11–15]. RP versus NP provides higher column nation of tocopherols in oils have been reported stability, reproducibility of retention times, quicker [1,8,9]. However, they involve saponification, which equilibration and shorter analysis time [9,16]. More- over, RP-HPLC solvent systems preserve the en- vironment more than those used in NP-HPLC [17]. *Corresponding author. Tel.: 134-93-4024-512; fax: 134-93- In contrast, NP, unlike RP, resolves b- and g- 4021-896. tocopherols [9,18]. However, one procedure using ´ E-mail address: mclop@farmacia.far.ub.es (M.C. Lopez-Saba- ter) RP has been reported to allow an acceptable sepa- 0021-9673 / 00 / $ – see front matter  2000 Elsevier Science B.V. All rights reserved. PII: S0021-9673(00)00219-3