Ordered nanoporous carbon (CMK-3) coated fiber for solid-phase microextraction of benzene and chlorobenzenes in water samples

Abstract

Nanoporous carbons (CMK-3) were prepared and have been used as a fiber coating for headspace solid phase microextraction (HS-SPME). The prepared materials were characterized by Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and N₂ adsorption/desorption isotherms. The efficiency of the fiber was evaluated using a gas chromatography (GC) system for the extraction of benzene (B) and chlorobenzenes (CBs) from the headspace of aqueous samples. The prepared nanomaterial was coated onto a copper wire for fabrication of the SPME fiber. These fibers featured advantages like easy and fast preparation, high thermal and mechanical stability. To optimize different parameters which influence the extraction efficiency such as sample volume, extraction temperature, extraction time, ionic strength and stirring rate, a Taguchi OA₁₆ (4⁵) orthogonal array experimental design was used. Based on the results obtained from the analysis of variance (ANOVA), the optimum conditions for extraction were established as: 12 mL sample volume; laboratory temperature; 20 % (w/v) NaCl; 35 min extraction time and stirring rate of 600 rpm. Under the optimized conditions for B and CBs, the linearity was from 2.5 to 800 µg/L, the relative standard deviation (RSD %) of the method was between 5.2 and 9.3% and limit of detections (LODs) was between 0.09 and 0.28 µg/L. The recovery values were from 85.40% to 104.20 % in water samples. Finally, the applicability of the proposed method was evaluated by the extraction and determination of B and CBs in the water samples.