DES-based vortex-assisted liquid-liquid microextraction procedure developed for the determination of paraben preservatives in mouthwashes

A green deep eutectic solvent-based vortex-assisted liquid–liquid microextraction (DES-VALLME) procedure for the determination of parabens in mouthwashes was developed. Deep eutectic solvents formed by combining DL-menthol and decanoic acid in different mol ratios were prepared, the highest extraction recovery was obtained with DES consisting of 4:1 M ratio, and this DES was used as an extraction solvent for paraben determination in mouthwashes. The effect of parameters such as solution pH, mol ratio of DES composition, DES volume, vortex and centrifugation time and sample volume were examined. Optimum working conditions of the study; 400 µL DES, 3 min. vortex time, 5 min. centrifugation time, 5 mL sample volume were determined. The detection limit was in the range of 4.6–6.1 µg L−1, while the RSDs values were in the range of 0.70–1.41% in intraday and 1.27–2.41% in interday. The method in the study was successfully applied for the determination of methyl, ethyl, propyl and butyl paraben in 10 different mouthwashes obtained from cosmetic stores..