A New Composite of O-aminobenzene Sulfonic Acid Self-Doped Polyaniline and Multi-Walled Carbon Nanotubes as a Fiber Coating for Solid-Phase Microextraction Gas Chromatography

A new composite of o-aminobenzene sulfonic acid self-doped polyaniline (SPAN) and multi-walled carbon nanotubes was prepared on a stainless steel wire by electrochemical method as a headspace solid-phase microextraction fiber for gas chromatography. Preparation conditions were investigated, and the resulting composite coating was characterized via scanning electron microscopy, Brunauer–Emmett–Teller (BET) analysis and thermogravimetric analysis. Introduction of MWCNTs and o-aminobenzene sulfonic acid into the composite leads to formation of plenty of microglobules and mesopores and makes BET surface area and thermal decomposition temperature of the composite increase by ~ 340% and ~ 130 ℃, respectively, compared to common polyaniline coating. Extraction conditions were optimized, and chromatographic analysis of 2,4-dichlorophenol was conducted. Extraction efficiency of the new composite coated fiber increases by 320% compared to polyaniline-coated fiber. Relative standard deviations of peak areas are 4.3%, 6.3%, 7.1% ( n = 5) for identical fiber, fibers prepared in identical batch and different batches, respectively, exhibiting good repeatability and reproducibility. Detection limit is 1.30 ng L −1 (S/N = 3), and recoveries are in the ranges from 82.3 to 110.2%, from 91.5 to 109.4% and from 94.2 to 113.0% for three different water samples spiked at three levels of 500, 100 and 10 ng mL −1 , respectively.