Preparation and application of carbon nanotubes/poly( o ‐toluidine) composite fibers for the headspace solid‐phase microextraction of benzene, toluene, ethylbenzene, and xylenes

A novel nanocomposite coating of poly(o‐toluidine) and oxidized multiwalled CNTs (MWCNTs, where CNTs is carbon nanotubes) was electrochemically prepared on a stainless‐steel wire. The applicability of the fiber was assessed for the headspace solid‐phase microextraction of benzene, toluene, ethylbenzene, and xylenes in aqueous samples followed by GC with flame ionization detection. In order to obtain an adherent and stable composite coating, several experimental parameters related to the coating process, such as polymerization potential and time, and the concentration of o‐toluidine and oxidized MWCNTs were optimized. The combination of MWCNTs and polymer in a nanocomposite form presents desirable opportunities to produce materials for new applications. The effects of various parameters on the efficiency of the headspace solid‐phase microextraction process, such as desorption temperature and time, extraction temperature and time, and ionic strength were also investigated. At the optimum conditions, LODs were 0.03–0.06 μg/L. The method showed linearity in the range of 0.5–300 μg/L with coefficients of determination >0.99. The intraday and interday RSDs obtained at a 5 μg/L concentration level (n = 5) using a single fiber were 1.2–5.2 and 3.2–7.5%, respectively. The fiber‐to‐fiber RSD (%; n = 3) at 5 μg/L was 6.1–9.2%.