Electrochemical preparation of polyaniline–ionic liquid based solid phase microextraction fiber and its application in the determination of benzene derivatives

A polyaniline–ionic liquid (i.e. 1-butyl-3-methylimidazolium tetrafluoroborate, [C4mim][BF4]) composite film coated platinum wire (PANI–IL/Pt) was prepared by electrochemical method for the first time. Scanning electron microscopy image showed that the PANI–IL composite film was even and porous. When the PANI–IL/Pt was used as a fiber for the headspace solid-phase microextraction (HS-SPME) of some benzene derivatives (i.e. 1,3-dimethylbenzene, 1,2-dimethylbenzene, 1,4-dichlorobenzene, 1,2-dichlorobenzene, 1,3,5-trimethylbenzene and 1,2,4-trimethylbenzene), followed by gas chromatographic analysis, it presented excellent performance, which was much better than that of PANI/Pt and commercial polydimethylsiloxane fiber. Hence the fiber was coupled with gas chromatography for the determination of these benzene derivatives. It was found that under the optimized conditions the linear ranges were 0.04–400 μg L−1 with correlation coefficients above 0.99, the detection limits were 9.3–48.1 ng L−1 (S/N = 3), the relative standard deviations (RSDs) were smaller than 5.1% for five successive measurements with single fiber, and the RSDs for fiber-to-fiber were 5.0–11.1% (n = 3) for different benzene derivatives. The proposed method was successfully applied to the extraction and determination of benzene derivatives in waste water and tap water, and the recoveries were 87.1–108.1% for different analytes. Therefore, the PANI–IL/Pt is a promising SPME fiber.