Loading controlled magnetic carbon dots for microwave-assisted solid-phase extraction: Preparation, extraction evaluation and applications in environmental aqueous samples.

An adsorbent of carbon dot@poly(glycidyl methacrylate)@Fe3 O4 nanoparticles has been developed for the microwave-assisted magnetic solid-phase extraction of polycyclic aromatic hydrocarbons in environmental aqueous samples prior to high-performance liquid chromatography with UV/visible spectroscopy detection. Poly(glycidyl methacrylate) was synthesized by atom transfer radical polymerization. The chain length and amount of carbon dots attached on them can be easily controlled through changing polymerization conditions, which contributes to tunable extraction performance. The successful fabrication of the nano-adsorbent was confirmed by transmission electronic microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and vibrating sample magnetometry. The extraction performance of the adsorbent was evaluated by using polycyclic aromatic hydrocarbons as model analytes. The key factors influencing the extraction, such as microwave power, adsorption time, desorption time and desorption solvents were investigated in detail. Under the optimal conditions, the microwave-assisted method afforded magnetic solid-phase extraction with short extraction time, wide dynamic linear range (0.02-200 μg/L), good linearity (R2  ≥ 98.57%) and low detection limits (20-90 ng/L) for model analytes. The adsorbent was successfully applied for analyzing polycyclic aromatic hydrocarbons in environmental aqueous samples and the recoveries were in the range of 86.0-124.2%. Thus, the proposed method is a promising candidate for fast and reliable preconcentration of trace polycyclic aromatic hydrocarbons in real water samples.