A rapid GC-FID method for determination of sabinene, β-pinene, α-thujone and β-thujone in the essential oil of Kitchen Sage (Salvia officinalis L.)

Terpenes and terpenoids are dominant fragrances in the essential oils of many economically important fruits and vegetables. Hence, content and variation are important factors in the evaluation and common perception of food quality. Sabinene, β-pinene, α-thujone and β-thujone are examples of such compounds found in the different species of Sage. Sabinene and β-pinene are spicy compounds much used by the fragrance industry while the two thujones are highly toxic. Here, we report a rapid method for quantification of these compounds in the essential oil of Sage. The total analytical time is approx. 7,5 min in contrast to approx. 30 min for similar gas chromatographic methods. The analytical method had a linear range of 28-342 mg L^-1 for the different compounds, with an analytical precision of 0,6-0,9% for standards. Correlation coefficients were 0,9993-1,0000. The Limit of Detection of all compounds were 0,02-0,9 mg L^-1 and the Limit of Quantification were 0,08-3,0 mg L^-1. The technique was used for quantification of the compounds in seven commercial essential Sage oils and in a pilot study of the effect of ozone on the terpenes and terpenoids in fresh Sage leaves. Large variation was observed between the different commercial samples, of which some were thujone dominant and some did not have any content of thujone at all. Treatment of fresh Sage leaves with ozone caused degradation of the terpenes sabinene and β-pinene whereas the terpenoids α/β-thujone were more resistant to degradation.

Keywords: Hydrodistillation; Ozone; Surface sterilization; Terpene; Terpenoid.