Rapid evaluation and quantitative analysis of eugenol derivatives in essential oils and cosmetic formulations on human skin using attenuated total reflectance–infrared spectroscopy

We studied the fragrances 4-allylbenzenes (eugenol, methyl eugenol, acetyl eugenol) as well as 4-propenylbenzenes (isoeugenol) in commercial essential oils using a fast and nondestructive attenuated total reflectance–infrared (ATR–IR) spectroscopy method. The method was based on ATR–IR utilizing partial least square regression. The calibrations were modeled in the characteristic region for eugenol (1430–1432 cm⁻¹), isoeugenol (960–970 cm⁻¹) and methyl eugenol (803–807 cm⁻¹). The models were then applied to predict the percutaneous absorption process yield and to monitor the concentrations of eugenol derivatives on human skin.