Screening of Parabens in Natural Water by Salting-out Based Centrifugeless Dispersive Liquid-liquid Microextraction...

A simple, efficient and quick salting-out based centrifugeless dispersive liquid-liquid microextraction combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) has been successfully developed for the determination of selected parabens in environmental water samples. Herein, following the dispersion of the extracting solvent (1-undecanol) whose melting point is near the room temperature into the sample solution, the cloudy mixture is passed through a test tube filled with sodium chloride, acting as separating agent based on salting-out phenomenon. By immersing the tube inside an ice bath, the fine droplets of the extraction solvent are solidified, easily collected and after returning to the liquid state, injected into HPLC-UV. The values of the detection limit were in the range of 2.5-5.0 µg L-1 while the intra-day (n = 7) and inter-day (n = 9, within three days) precision were below 3.7 and 4.7%, respectively. A satisfactory linearity (0.997 ≥ r2 ≥ 0.996) and quite a broad linear range (5.0-250 µg L-1) were achieved. The relative errors as the accuracy were less than 6.4% in all experiments. The method was eventually employed for the preconcentration and determination of the analytes in various natural water samples and acceptable results were achieved.