An approach to the static–dynamic subcritical water extraction of laurel essential oil: comparison with conventional techniques

Abstract

The coupling of a subcritical extractor with a three-way inlet valve and an on/off outlet valve was used for performing static–dynamic subcritical water extractions for the isolation of essential oils. The applicability of the assembly was tested using laurel leaves as a model sample, but can be extended to other natural products. The compounds were removed from the aqueous extract by a single extraction with 5 ml of hexane, individually separated and detected by gas chromatography–flame ionisation detection and identified by electron ionization mass spectrometry. The proposed method was compared with both conventional (hydrodistillation and dichloromethane manual extraction) and recent (subcritical dichloromethane extraction) alternatives in terms of rapidity, efficiency, cleanliness, possibility of manipulating the composition of the oil and quality of the oil, revealing the proposed method to be clearly advantageous. This fact, together with the good precision for the overall method [(RSD <15% for n = 6) for each compound], make it a good alternative to both conventional and recent counterparts.