Ionic Liquid as a Ferrofluid Carrier for Dispersive Solid Phase Extraction of Copper from Food Samples

A novel, efficient, fast, and simple mode of dispersive solid phase extraction based on ferrofluid (FF-DSPE) was investigated for determination of copper in different environmental and food samples. Ionic liquids were used as carrier in this method. Due to rapid injection of ferrofluid into the aqueous sample by a syringe, the sorbent is highly dispersed in the bulk solution, so extraction can be achieved very fast. In addition, the ferrofluid can be attracted by a magnet and no centrifugation step is required for phase separation. The obtained results show that this method can be useful for routine trace laboratory analysis. The influence of different variables on the extraction yield was studied in detail. Under the optimized conditions, the calibration graph was linear over the range of 0.9–90 μg L⁻¹ and the enrichment factor (EF) 267 was obtained. The limit of detection was 0.32 μg L⁻¹ and the relative standard deviation of 2.6 % at 50 ng mL⁻¹ was obtained (n = 6). The method was validated using certified reference material and was successfully applied for determination of copper in various samples.