Synthesis of a graphitic carbon nitride nanocomposite with magnetite as a sorbent for solid phase extraction of phenolic acids

We have developed a facile in-situ growth method for the deposition of magnetite (Fe 3 O 4 ) particles on the surface of a graphitic carbon nitride (g-C 3 N 4 ) nanosheet. The material was characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The high affinity of g-C 3 N 4 for phenolic acids in combination with the magnetism of Fe 3 O 4 provides an efficient means for magnetic solid phase extraction. The adsorption, desorption and recoveries were examined. Under optimized conditions, the method has limits of detection in the range from 17.5–42.6 ng mL −1 (at an S/N of 3), and precisions from 2.8–3.8 % (for n  = 5). The method was successfully applied to the determination of protocatechuic, caffeic, and ferulic acids in Salicornia herbacea L . plant extracts. Recoveries ranged from 92.4–99.5 %. The high affinity of g-C 3 N 4 toward the phenolic acids as well as the magnetic behavior of Fe 3 O 4 were combined in this nanocomposite material to provide an efficient and simple magnetic solid phase extraction (MSPE) approach.