Fast authentication of tea tree oil through spectroscopy

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Chemometrics

Background:

• Tea tree oil (TTO) authentication is crucial for quality control.
• Traditional methods like 2D-GC/MS are time-consuming and costly.
• Developing rapid, cost-effective, and environmentally friendly analytical methods is needed.

Purpose of the Study:

• To develop and validate new infrared spectroscopy-based procedures for TTO authentication.
• To compare the performance of Near-Infrared (NIR) and Mid-Infrared (MIR) spectroscopy methods.
• To evaluate the developed methods from a Green Analytical Chemistry perspective.

Main Methods:

• Infrared measurements using transmission NIR and Attenuated Total Reflectance (ATR) on untreated TTO samples.
• Partial Least Square Discriminant Analysis (PLS-DA) for data analysis and model building.
• Validation using a set of 267 authentic and non-authentic TTO samples.

Main Results:

• Both NIR and ATR methods achieved 98% certainty in discriminating authentic from non-authentic TTO samples.
• The developed infrared methods provide a fast and low-cost alternative to conventional techniques.
• The study successfully built discriminant models based on wavenumber selection and data pre-processing.

Conclusions:

• Infrared spectroscopy (NIR and ATR) coupled with PLS-DA is a reliable and efficient tool for TTO authentication.
• These methods offer significant advantages in terms of speed, cost, and environmental impact compared to existing techniques.
• The developed methodologies represent a promising advancement in the quality control of TTO.