Microwave-assisted extraction of oxygen heterocyclic compounds from Citrus-scented creams using a deep eutectic solvent and their determination by HPLC-PDA

This study aimed to investigate the content of oxygen heterocyclic compounds, especially coumarin and furocoumarins, in cosmetics products scented with Citrus essential oils. A minor component of the non-volatile fraction of Citrus essences is composed by oxygen heterocyclic compounds, commonly known as coumarins, furocoumarins, and polymethoxyflavones. These molecules show several biological effects on human health. On the other hand, coumarin has the potential to induce skin sensitization and furocoumarins show phototoxic activity. For this reason, several regulation and opinions have been issued concerning the maximum amount of these compounds in cosmetics. Given the regulatory framework, an analytical workflow for extraction and quantification of OHCs from cosmetics is necessary. This research aims to address this challenge by exploring, for the first time, a deep eutectic solvent as eco-friendly alternative for microwave-assisted extraction of these molecules from Citrus-scented creams. A deep eutectic solvent made by chloride and urea, at a molar ratio 1:2, and 20 % of water in weight was selected. Due to the complexity of the sample, a SPE clean-up was mandatory to obtain an extract devoid of interferents. Finally, an HPLC-PDA analytical method was employed allowing the simultaneous separation and quantification of 35 oxygen heterocyclic compounds in less than ten minutes. The analytical workflow here proposed was developed, optimized and validated demonstrating the potentials of deep eutectic solvents and microwaves in this field.