A Deep Eutectic Solvent as an Extraction Solvent to Separate and Preconcentrate Parabens in Water Samples Using in situ Liquid-Liquid Microextraction

<div><p>In this study, an in situ deep eutectic solvent-liquid-liquid microextraction method together with high performance liquid chromatography was developed for the determination of parabens in aqueous sample. The hydrophobic deep eutectic solvent, formed in situ by the DL-menthol and decanoic acid was used as the extraction solvent. Various parameters affecting the extraction efficiency including the composition of deep eutectic solvent, temperature of sample solution, extraction time, solution pH and salt concentration were investigated and optimized. Under the optimum conditions, the linear range of calibration curves was in the range of 3-1000 ng mL-1. The limits of detection and limits of quantification were in the range of 0.6-0.8 and 2.0-2.5 ng mL-1, respectively. The relative standard deviations were less than 7.2% for both intra-day and inter-days analysis. Finally, the proposed method was successfully applied to determine four parabens in environmental water samples with acceptable recoveries.</p></div>