New polypyrrole-carbon nanotubes-silicon dioxide solid-phase microextraction fiber for the preconcentration and determination of benzene, toluene, ethylbenzene, and o-xylene using gas liquid chromatography.

For the first time, a polypyrrole-carbon nanotubes-silicon dioxide composite film coated on a steel wire was prepared by an electrochemical method. Scanning electron microscopy images showed that this composite film was even and porous. The prepared fiber was used as an absorbent for the headspace solid-phase microextraction of benzene, toluene, ethylbenzene, and o-xylene, followed by gas chromatographic analysis. This method presented an excellent performance, which was much better than that of a polypyrrole-carbon nanotube fiber. It was found that under the optimized conditions, the linear ranges were 0.01-200 ng/mL with correlation coefficients >0.9953, the detection limits were 0.005-0.020 ng/mL, the relative standard deviations were 3.9-6.4% for five successive measurements with a single fiber, and the reproducibility was 5.5-8.5% (n = 3). Finally, the developed method was successfully applied to real water samples, and the relative recoveries obtained for the spiked water samples were from 91.0 to 106.7%.