Determination of α-Tocopherol in Olive Oil by Solid-Phase Microextraction and Gas Chromatography–Mass Spectrometry

ABSTRACT

Olive oil has great human health benefits and is an important component of the Mediterranean diet. Its quality, sensory attributes, and oxidative stability are linked to the presence of minor compounds. Vitamin E (α-tocopherol) is a key component in these properties. In this work, solid-phase microextraction coupled to gas chromatography–mass spectrometry was used for the determination of α-tocopherol in olive oil. The analytical performance of the method has been assessed in fortified olive oil with negligible vitamin E concentrations. The calibration curve was linear from 0.020 to 0.500 mg/g. The limits of detection and quantification were 0.006 and 0.021 mg/g, respectively. Intraday and interday relative standard deviations were 3.2 and 10.0, respectively, and were concentration independent. The method was used for the determination of α-tocopherol in virgin and extra virgin olive oil, reporting average concentrations of 0.044 ± 0.03 and 0.200 ± 0.05 mg/g, respectively. Overall, the method is simple, sensitive, rapid, and solvent free, and provided high recoveries of 97.7 ± 3.1%. In addition, vitamin E stability in extra-virgin olive oil was characterized by a shelf-life study.

KEYWORDS:

• α-tocopherol
• DI-SPME
• GC-MS
• olive oil

Acknowledgment

The authors are grateful to Dr. Daniele Urso for his experimental help.

Conflict of interest

The authors declare that they have no conflicts of interest. This article does not contain any studies with human participants or animals performed by any of the authors. Informed consent is not applicable to this work.