Graphene intercalated with carbon nanosphere: a novel solid-phase extraction sorbent for five carbamate pesticides

Graphene-carbon nanosphere composite (G@CNS) was prepared via a simple hydrothermal method. The G@CNS nanocomposite was characterized by X-ray diffraction, scanning electron microscope, surface area, and porosity analysis. The G@CNS was applied as a new sorbent for solid-phase extraction of five carbamate pesticides (tsumacide, carbaryl, isoprocarb, bassa, diethofencarb) prior to quantitative determination by high-performance liquid chromatography with ultraviolet detection at 208 nm. Some experimental parameters including desorption conditions, sample pH, sample volume, and loading rate were studied carefully. Under the optimized condition, the method provided good linearity ranging from 0.3 to 100.0 ng mL(-1) with low limits of detection of 0.10-0.20 ng mL(-1) for grape juice, 0.10-0.30 ng mL(-1) for blend fruit juice, and 0.10-0.20 ng mL(-1) for water sample. Good method recoveries (80.2-110%) with relative standard deviations less than 7.2% and high enrichment factors (167-293) were achieved. Results demonstrated that this novel G@CNS can serve as a promising alternative sorbent for more applications.