Dispersive solid phase extraction based on simply prepared nitrogen-doped amorphous carbon nanocomposite combined with dispersive liquid–liquid microextraction: application in the extraction of some pesticides from fruit juices

In the present survey, a nitrogen-doped amorphous carbon nanocomposite has been prepared simply and eco-friendly from heating an acidic solution of sorbitol and urea. It was used as an efficient sorbent in dispersive solid phase extraction for the extraction of some pesticides (chlorpyrifos, diniconazole, clodinafop–propargyl, oxadiazon, fenpropathrin and penconazole) from fruit juice samples. The method was followed by a dispersive liquid–liquid microextraction procedure for more preconcentration of the analytes. The extracted analytes were determined by gas chromatography–flame ionization detection. Under optimized experimental conditions, relative standard deviations were in the ranges of 3–5% and 5–7% for intra-day (n = 6) and inter-day (n = 4) precisions, respectively, at a concentration of 10 μg L−1 for each analyte. The limits of detection and quantification were in the ranges of 0.89–1.3 and 3.0–4.3 μg  L−1, respectively. The linear ranges were achieved in the range of 3.0–2000 μg L−1. Also, enrichment factors and extraction recoveries were obtained in the ranges of 380–455 and 76–91%, respectively. Finally, the developed approach was performed to determine the studied pesticide residues in various fruit juices including pomegranate, sour cherry, grape, orange and apple.