Designing a green device to BAμE: Recycled cork pellet as extraction phase for the determination of parabens in river water samples.

This study reports a novel and environmentally friendly method based on bar adsorptive microextraction (BAμE) with cork pellet as extraction phase for the determination of methylparaben, ethylparaben, propylparaben and butylparaben in river water samples. This natural approach consists of a cork pellet recycled from wine stoppers used as biosorbent material to replace the traditional BAμE device. The analytical determinations were performed using a high-performance liquid chromatography-diode array detector (HPLC-DAD). Parameters such as type of desorption solvent, desorption and extraction time, sample pH and ionic strength were carefully optimized through univariate and multivariate approaches. Cork pellets of 15 mm length were inserted into vials containing 15 mL of water sample adjusted at pH 3 and 25% (w/v) of NaCl. The extraction step was carried out under agitation for 45 min followed by liquid desorption with 120 μL of methanol:acetonitrile (1:1 v/v) for 30 min. Satisfactory analytical performance was obtained with coefficients of determination ranging from 0.9921 for methylparaben to 0.9994 for propylparaben; intraday precision ranged from 6.7 to 18.3%, and interday precision varied from 7.2 to 20.0%. Accuracy was assessed through relative recovery assays and varied from 53 to 124%.