Food Analytical Methods

, 2:120

Rapid Determination of α-Tocopherol in Vegetable Oils by Fourier Transform Infrared Spectroscopy

  • Sandra D. Silva
  • Nuno F. Rosa
  • António E. Ferreira
  • Luís V. Boas
  • Maria R. Bronze
Article

DOI: 10.1007/s12161-008-9047-y

Cite this article as:
Silva, S.D., Rosa, N.F., Ferreira, A.E. et al. Food Anal. Methods (2009) 2: 120. doi:10.1007/s12161-008-9047-y

Abstract

The aim of this study was to develop a rapid methodology for the analysis of α-tocopherol in vegetable oils as an alternative to the high-performance liquid chromatography (HPLC) methods: Fourier transform infrared (FT-IR) methodology. Thirteen vegetable oils (corn, peanut, soybean, sunflower and mixtures) commercially obtained were analysed by reverse-phase HPLC with fluorescence detection (FD) in order to obtain standard values for α-tocopherol. Validation tests were performed concerning the HPLC method. The HPLC method is valid for α-tocopherol analysis in the 1–90 mg/L linear range. Method repeatability was 3.6%, and accuracy results were within 70–95%. FT-IR spectra of the vegetable oils were acquired in the attenuated total reflection mode (45° and 60° crystals of ZnSe). To predict the α-tocopherol content in samples, calibration models were designed, and the partial least squares method was used to analyse data from FT-IR spectral region at 1,472–1,078 cm−1. Results obtained showed that the calibration model implemented with a 45° crystal is more suitable for the proposed analysis. Five extra samples of vegetable oils were analysed by HPLC/FD and by FT-IR. Using the calibration model implemented for FT-IR (45° crystal), the α-tocopherol content in samples was determined. The results obtained by HPLC/FD and FT-IR were compared, and there were no significant differences among them. Results showed that FT-IR can be used as an alternative method for rapid screening of α-tocopherol in vegetable oils without sample pre-treatment.

Keywords

Vegetable OilsVitamin Eα-TocopherolFT-IRHPLCPLS Calibration

Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Sandra D. Silva
    • 1
    • 2
  • Nuno F. Rosa
    • 1
    • 3
  • António E. Ferreira
    • 1
  • Luís V. Boas
    • 1
    • 2
  • Maria R. Bronze
    • 1
    • 2
    • 4
  1. 1.Instituto de Biologia Experimental e TecnológicaOeirasPortugal
  2. 2.Instituto de Tecnologia Química e BiológicaOeirasPortugal
  3. 3.Escola Superior de Biotecnologia/Escola de Tecnologia e Gestão IndustrialSintraPortugal
  4. 4.Faculdade de Farmácia de LisboaLisboaPortugal