Development and Evaluation of a Capillary Column GC-FID Identification Test for Sage Oil and Sage Water Listed in the...

Identification tests based on gas chromatography (GC) with a flame ionization detector (GC-FID) are specified for sage oil (SO) and sage water (SW) in the Japanese Standards of Quasi-Drug Ingredients. In the current methods, a packed column (PC) is used for both products, causing prolonged analysis and limited separation efficiency. In addition, sage extract (SE) is designated as the reference standard for the SW identification test; however, its major constituents remain uncharacterized. The capillary column (CC) has become the standard in recent GC procedures, making PC replacement with CC desirable for SO and SW. In this study, we aimed to improve CC-based GC-FID identification tests for SO and SW. The separation behavior of the SO marker components, including α-pinene, thujone, and camphor, was first examined using GC-MS, which demonstrated good separation using CC. Rapid GC conditions were subsequently evaluated, achieving a substantial reduction in analysis time while maintaining sufficient separation and detection sensitivity. The analysis of SW and SE revealed that α-thujone, camphor, and 1,8-cineole were the common major components. However, dilution with ethanol occasionally hindered the visual recognition of marker components. The application of hexane liquid-liquid extraction (Hex-LLE) as a sample pretreatment effectively removed these interfering components, enabling the clear identification of marker compounds even in aqueous samples. These results demonstrate that the combination of CC-based GC-FID and Hex-LLE provides an effective and practical approach for the identification of SO and SW. The method may be applicable to other plant-derived essential oils and aromatic distilled waters.