Purity Analysis of Adulterated Essential Oils by FT-IR Spectroscopy and Partial-Least-Squares Regression.

This study reports a combined use of ordinary Fourier transform infrared spectroscopy (FT-IR) in conjunction with partial-least-squares (PLS) multivariate regression for accurate determination of the percent compositions of four essential oils (EOs) (wintergreen, tea tree, rosemary, and lemon eucalyptus oils) that were adulterated either with lemongrass essential oil or peppermint essential oil. The FT-IR spectra of the calibration sample sets of known compositions of adulterated EOs with lemongrass oil or peppermint oil were measured and subjected to PLS multivariate regression analysis. The simplicity, low cost, and high accuracy of the protocol makes it appealing for routine industrial quality assurance of consumable goods. [ABSTRACT FROM AUTHOR]