Preparation of magnetic graphene nanocomposite based on metallic iron and its application in the extraction and preconcentration of some pesticides from fruit juice, river water, and wastewater samples

A dispersive solid-phase extraction method using a synthesized magnetic graphene nanosorbent followed by dispersive liquid–liquid microextraction has been developed for the extraction of some pesticides from fruit juice, river water, and wastewater samples. The magnetic nanosorbent was added into an aqueous solution containing the analytes and vortexed. The analytes were rapidly adsorbed onto the nanosorbent by binding to its graphene. In the presence of an external magnetic field, the nanosorbent particles were isolated from the aqueous solution. Then, an appropriate elution solvent (methanol) was used to desorb the compounds of interest from the nanosorbent samples. For further enrichment of the analytes, the obtained eluate was mixed with 1,2-dibromoethane (as an extraction solvent) and injected into deionized water in order to dissolve methanol into water and achieve a sedimented phase at µL level containing the enriched analytes. Under the optimum conditions, the limits of detection and quantification were obtained in the ranges of 0.40–1.3 and 1.3–4.3 µg L −1 , respectively. The enrichment factors and extraction recoveries for the pesticides ranged from 309 to 443 and 62–88%, respectively. Finally, the proposed method was successfully applied for analysis of the selected pesticides at µg L −1 level in different samples.