Determination of Volatile Compounds in Antioxidant Rosemary Extracts by Solid‐Phase Microextraction and Gas Chromatography

Abstract

A method based on headspace solid‐phase microextraction (HS‐SPME) and gas chromatography for determining residual volatile compounds in commercial rosemary (Rosmarinus officinalis) extracts is proposed. Twenty‐four volatile compounds were identified by gas chromatography‐mass spectrometry, and 12 of them were selected and quantified by HS‐SPME gas chromatography‐flame ionisation detection. The influences of the HS‐SPME variables, such as type of fiber, water addition to the solid sample, incubation time and temperature, and extraction time were studied. The final working conditions were a 50/30 µm divinylbenzene‐carboxen‐polydimethylsiloxane fiber, water addition, 15‐min incubation at 70°C and 60‐min extraction at room temperature. The signals obtained by HS‐SPME were higher than those recorded by static headspace. The features of the method were established for volatile compound standard solutions in water. Finally, the method was applied to the analysis of solid and liquid commercial rosemary extracts. Calibration was performed by both external standard (using aqueous volatile compound standard solutions) and standard addition, and the results obtained were compared. Financed by the Ministerio de Educación y Ciencia (CTQ2004‐01229 project), the Consejería de Educación, Cultura y Deportes of the Gobierno de La Rioja (ANGI2002/17 and ANGI2004/10 projects) and by the University of La Rioja (API02/31 project). José David Carrillo‐Zamajón thanks the Comunidad Autónoma de La Rioja for his grant.