Solid phase microextraction of polycyclic aromatic hydrocarbons from water samples by a fiber coated with covalent organic framework modified carbon nitride

A covalent organic framework modified graphitic carbon nitride (g-C3N4@TpBD) was synthesized by modifying the graphitic carbon nitride (g-C3N4) with a covalent organic framework (COF-TpBD). The synthesis conditions including the mass ratio between g-C3N4 and benzidine (BD), solvent type, reaction temperature and reaction time were optimized. Under the optimal synthetic conditions, a novel spiny dendritic g-C3N4@TpBD adsorbent was obtained. The g-C3N4@TpBD was then coated on stainless-steel wire by sol gel technique and the coated fiber was used for the solid phase microextraction of polycyclic aromatic hydrocarbons prior to gas chromatography-mass spectrometric detection. The established method was successfully applied to determine eight PAHs in six environmental water samples. Under the optimal extraction conditions, a wide linear quantification range for the analytes was obtained from 0.07 to 60.0 ng mL(-1) with the coefficients of determination varying from 0.9979 to 0.9998, and the limits of detection (S/N=3) ranged from 0.02 to 0.05 ng mL(-1). The relative recoveries of the analytes for the six environmental water samples at the spiked concentrations of 0.2, 0.5, 3.0 and 30.0 ng mL(-1) were between 83.6% and 118% with the relative standard deviations ranging from 2.4% to 11.3%. (C) 2020 Elsevier B.V. All rights reserved.