Gas chromatographic quality control for oil of Melaleuca terpinen-4-ol type (Australian tea tree)

Detailed GC and GC-MS analyses of oil of Melaleuca have identified several constituents not previouslyreported from Melaleuca alternifolia and clarified some earlier assignments. The range, mean, andcoefficient of variation for the principle constituents in 800 typical samples are presented along withthe compositions of several substandard oils. Isolation and storage procedures affecting the chemicalcomposition of the oil are reported. Ethanolic extraction of mature leaves gave solutions suitable fordirect injection into a gas chromatograph for the qualitative determination of tea tree oil. Comparisonwith conventional steam distillation showed that this technique was suitable for preliminary analysisof tea tree oil yield and quality.