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Enantiomeric distribution of selected terpenes for authenticity assessment of Australian Melaleuca alternifolia oil


Wong, YF and Davies, NW and Chin, S-T and Larkman, T and Marriott, PJ, Enantiomeric distribution of selected terpenes for authenticity assessment of Australian Melaleuca alternifolia oil, Industrial Crops and Products, 67 pp. 475-483. ISSN 0926-6690 (2015) [Refereed Article]

Copyright Statement

Copyright 2015 Elsevier B.V.

DOI: doi:10.1016/j.indcrop.2015.01.066


The growing awareness of a mounting trend toward adulteration of essential oil products has resulted in considerable interest among producer and consumer industries to develop suitable and cost-effective methods for authenticity control. In response to this trend, this study reports authenticity assessment of Australian tea tree oil (TTO) by means of stereospecific analysis of designated chiral monoterpenes present within the oil. Enantioselective gas chromatography (eGC) coupled with either flame ionisation detection or mass spectrometry was used to determine the enantiomeric distribution of terpinen-4-ol and α-terpineol, both key chemical markers in TTO. Consistent enantiomeric ratios of 68.50.2% (+) : 31.50.2% (‒) for terpinen-4-ol and 74.21.4% (+) : 25.81.4% (‒) for α-terpineol were observed for the 57 authentic 100% pure Australian TTOs analysed, which were sourced directly from different plantation sites throughout Australia. On the other hand, considerable variations from these ratios were observed for a number of commercial TTOs sampled from different continents, with 50% of the samples varying markedly from the ~ 68.5% value found for (+)terpinen-4- ol. Robustness of the method and reliability of the attained results were evaluated by cross checking data derived from the two independent analyses performed in this study. To the best of our knowledge, this work encapsulates the most comprehensive dataset currently available for the enantiomeric distribution of terpinen-4-ol and α-terpineol in pure Australian TTO, and which can serve as an important reference for detection of variation in commercially-sourced samples, and be a potential indicator of adulteration. Additionally, results of this study proved the considerable potential of using chiral compositions of terpinen-4-ol and α-terpineol as chiral signatures for authenticity assessment of TTO.

Item Details

Item Type:Refereed Article
Keywords:tea tree oil, adulteration, enantioselective gas chromatography, terpinen-4-ol, α-terpineol, authenticity assessment
Research Division:Chemical Sciences
Research Group:Analytical chemistry
Research Field:Quality assurance, chemometrics, traceability and metrological chemistry
Objective Division:Plant Production and Plant Primary Products
Objective Group:Industrial crops
Objective Field:Essential oil crops
UTAS Author:Davies, NW (Associate Professor Noel Davies)
ID Code:98086
Year Published:2015
Web of Science® Times Cited:15
Deposited By:Central Science Laboratory
Deposited On:2015-02-02
Last Modified:2017-11-02

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