Solid phase microextraction of polycyclic aromatic hydrocarbons by using an etched stainless-steel fiber coated with a covalent organic framework.

A new covalent organic framework (COF) was synthesized by the amide coupling between 1,3,5-tris(4-aminophenyl)benzene and trimesoyl chloride at room temperature. The COF was applied as a steel fiber coating for the solid phase microextraction of polycyclic aromatic hydrocarbons (PAHs) from water samples. The effect of extraction time, salt concentration, and extraction temperature on the efficiency of SPME was optimized by a Box-Behnken design. The PAHs were quantified by gas chromatography with mass spectrometric detection. Figures of merit include (a) a wide linear range (typically from 0.2 ng L-1 to 2 μg L-1), (b) low limits of detection (0.29 to 0.94 ng L-1 at S/N = 3), and (c) high enrichment factors (EFs; 819-2420). Density functional theory was employed to study the interaction between the COF cluster and the PAHs. The results demonstrated that the EFs increase with the enhancement of π stacking interaction. The repeatability (one fiber; n = 5) and reproducibility (fiber to fiber; n = 5), expressed as the relative standard deviations were in the range of 4.3%-8.4% and 8.5-11.0%, respectively. The recoveries of the PAHs from water samples spiked at levels of 20.0 and 100 ng L-1 ranged from 79.0% to 105.0%. Graphical abstract A covalent organic framework prepared from 1,3,5-tris(4-aminophenyl)benzene and trimesoyl chloride (TAPB-TMC-COF) was synthesized and employed as solid phase microextraction (SPME) fiber coating for the extraction of polycyclic aromatic hydrocarbons from water samples prior to gas chromatography (GC) - mass spectrometric (MS) detection.