Poly(o-phenylenediamine-co-o-toluidine)/modified carbon nanotubes composite coating fabricated on a stainless steel wire for the headspace solid-phase microextraction of polycyclic aromatic hydrocarbons

• A nanocomposite made of PoPD-co-PoT and CNTs is electrochemically prepared.
• The composite is prepared on a steel wire.
• The extraction capability of the composite is examined towards PAHs.

A new nanocomposite sorbent including poly(o-phenylenediamine-co-o-toluidine) and modified carbon nanotubes was electrodeposited on a stainless steel wire from the corresponding aqueous solution by applying constant deposition potential. Characterization of the nanocomposite was performed using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) methods. Then, the extraction capability of this sorbent was evaluated by headspace solid-phase microextraction (HS-SPME) of polycyclic aromatic hydrocarbons (PAHs) from aqueous samples prior to gas chromatography–mass spectrometry (GC–MS) detection. The effective parameters on electrodeposition process (i.e., the voltage of power supply, the electrodeposition time, the concentration of o-phenylenediamine and o-toluidine, and modified carbon nanotubes doping level) were optimized. The main parameters affecting the extraction performance (i.e., desorption conditions, extraction temperature and time, and salt addition) were also investigated. Validation experiments showed that the optimized method had good linearity (0.9852–0.9975) over the concentration ranges from 0.01 to 100 μg L− 1 for majority of the analytes, low detection limit (1–6 ng L− 1), satisfactory single fiber repeatability (4.1–6.7%) and high recovery (88.9–102.5%). Inter-day relative standard deviation and fiber-to-fiber reproducibility at 1 μg L− 1were in the range of 5.0–8.2% and 6.6–11.4%, respectively. These results demonstrated that poly(o-phenylenediamine-co-o-toluidine)/modified carbon nanotubes (PoPD-co-PoT/MCNTs) can be a suitable coating for future applications of SPME in trace analyses from environmental samples.