Ordered nanoporous carbon as an effective adsorbent in solid-phase microextraction of toluene and chlorinated toluenes in water samples

Ordered nanoporous carbon (CMK-3) has been synthesized and immobilized onto a copper wire, and subsequently applied to headspace solid phase microextraction (HS-SPME) of toluene, 4-chlorotoluene, 2,4-dichlorotoluene and 2,6-dichlorotoluene following gas chromatography-flame ionization detection (GC-FID). The structural order and textural properties of the prepared materials have been characterized by N2 sorption analyses, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Five experimental parameters such as extraction temperature, extraction time, salt concentration and stirring speed have been evaluated and optimized by means of a Taguchi's OA16(45) orthogonal array experimental design. The experimental results indicate that extraction temperature and extraction time are the most significant factors in the analysis procedure. The optimum extraction conditions were as follows: 12 mL sample volume; ambient temperature; 10% (w/v) NaCl; 35 min extraction time and stirring rate of 600 rpm. Under the optimized conditions for all analyzed compounds, the linearity was from 2.5 to 400 μg L−1, and limit of detections (LODs) were between 0.02 and 0.08 μg L−1. The relative standard deviation values were ⩽5.25% and recovery values were between 85.60% and 104.12%. This method has been successfully used for preconcentration and analysis of above mentioned compounds in different real water samples.