Gas chromatography for β-caryophyllene determination in St. John’s wort infused oil
Hypericum Perforatum L., commonly known as St. John’s wort, is one of the best-known medicinal herbs. St. John’s wort infused oils are mostly used externally, but can be taken orally for stomach ulcers, are used as a food supplement. Therefore, it is important to develop methods that allow a rapid and reliable determination of β-caryophyllene, which is one of the main active components of St. John’s wort. In this work, two gas chromatographic techniques, static headspace gas chromatography (SHS-GC) and solid phase microextraction, combined with gas chromatography-mass spectrometry (SPME-GC-MS), were examined for the determination of β-caryophyllene in St. John’s wort infused oils. A comparison of these two techniques revealed that SPME-GC-MS can be successfully applied for the analysis. The other method, SHS-GC, is simple and fast, but because of its high detection limit, it can only be applied to oil samples with β-caryophyllene concentration higher than 0.1 mg/g.