A novel needle trap device containing an imine-based covalent organic framework for sampling of PAHs in soil

A new adsorbent based on covalent organic frameworks (COFs) was synthesized through imine condensation and utilized for the needle trap device (NTD) microextraction. The structure and surface properties of the synthesized adsorbent were investigated using Fourier-transform infrared spectroscopy (FT-IR), scanning electron micro-scopy (SEM), energy dispersive X-ray analysis (EDX), Brunauer-Emmett-Teller (BET) surface area analysis, and X-ray diffraction analysis (XRD), techniques. The designed microextraction system was coupled with a gas chro-matography flame ionization detector (GC-FID) and used for the measurement of polycyclic aromatic hydro-carbons (PAHs) in contaminated soil samples. The statistical response surface methodology (RSM) with a Box-Behnken design (BBD) was used to investigate and optimize the effective variables in the extraction process, including extraction temperature, extraction time, and sample flow rate. Under optimal conditions, the cali-bration curves were linear over the range of 0.2-10000 ng g-1. The detection limit of the method for the PAHs was obtained in the range of 0.01-0.05 ng g-1. The RSD values were obtained 7.6-12.9%. The NTD-GC-FID procedure based on COF adsorbent was successfully utilized for the analysis of PAHs in contaminated soil samples.

Automated summary

A new adsorbent based on covalent organic frameworks (COFs) was synthesized and used for the needle trap device (NTD) microextraction. The synthesized adsorbent was characterized using various techniques. The designed microextraction system coupled with GC-FID was used for the analysis of PAHs in contaminated soil samples. RSM with BBD was utilized to optimize the extraction process variables. Under optimal conditions, the method showed good linearity, low detection limit, and acceptable RSD values.