Determination of trans-anethole in Salvia sclarea essential oil by liquid chromatography and GC-MS

Liquid chromatographic (HPLC) and GC‐MS methods were developed to confirm the unusual presence of trans‐anethole in Salvia sclarea essential oil. The selectivity of the HPLC method with a diode array detector (DAD) was enhanced by a post‐column on‐line photochemical derivatization. When a photoreactor (equipped with a 254 nm UV lamp) was arranged between the analytical column and the DAD, photoinduced modification of the anethole chromophore resulted in modified spectral properties. Therefore, two UV spectra (photoreactor Off and On) were achieved for the photoreactive trans‐anethole, providing an information rich detection system. Using both HPLC and GC‐MS approaches the unambiguous confirmation of the occurrence of trans‐anethole in some commercial samples of S. sclarea oil was obtained. Genuine samples of S. sclarea essential oil were also prepared from the “drug” by each of the following techniques: steam‐distillation, Soxhlet extraction in n‐hexane, cold extraction in diethyl ether. GC‐MS analysis of all the above extracts revealed the presence of trans‐anethole. Although not previously recognized, trans‐anethole is to be considered a “normal” component of S. sclarea essential oil.