Micro-solid phase extraction of chlorophenols using reduced graphene oxide functionalized with magnetic nanoparticles and graphitic carbon nitride as the adsorbent.

A magnetic micro-solid phase extraction method was applied for the extraction of trace levels of various chlorophenols prior to their determination by high performance liquid chromatography. The reduced graphene oxide functionalized with magnetic iron oxide nanoparticles and graphitic carbon nitride was prepared and used as adsorbent. It was characterized by scanning electron microscope, X-ray diffraction and vibrating sample magnetometer. Placed in a polypropylene hollow tube, the material was applied to the extraction of 3-chlorophenol, 2,3-dichlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol in cosmetic samples. Several experimental parameters that affect extraction efficiency were optimized. Following desorption with alkaline methanol, the chlorophenols were quantified by high performance liquid chromatography. A linear response was observed in the 1.0-200 μg·kg-1 CP concentration ranges. The detection limits (at a signal-to-noise ratio of 3) are between 0.20 and 0.30 μg·kg-1. The relative recoveries of the CPs from spiked cosmetics samples were in the range from 80.5 to 104%, with relative standard deviations lower than 12%. The filled extraction tube is high durable and stable. It can be used for 120 extraction cycles without a significant loss of extraction efficiency. The good adsorption ability of the sorbent was attributed to the strong π stacking interaction between the graphitic carbon nitride functionalized reduced graphene oxide and the aromatic rings in the CPs. Graphical abstract A magnetic micro-solid phase extraction (M-μSPE) method was applied to the extraction of various trace chlorophenols prior to their determination by high performance liquid chromatography. The M-μSPE method combines the advantages of both MSPE and μSPE.