A simple strategy based on fibers coated with surfactant-functionalized multiwalled carbon nanotubes to improve the properties of solid-phase microextraction of phenols in aqueous solution

Abstract

A functionalized multiwalled carbon nanotube (MWCNT)-coated solid-phase microextraction (SPME) fiber was developed for concentrating analytes in aqueous samples. Sodium deoxycholate(NaDC) was used as a wrapping layer for non-covalent modification of MWCNTs. Non-covalent bonding between the MWCNTs and sodium deoxycholate changed the electrical and steric resistance of the MWCNTs, and improved their solubility and dispersibility. To investigate the capability of this MWCNTs/NaDC SPME fiber, it was applied to the analysis of phenols in aqueous solution. After extraction, the analytes were desorbed in an acetonitrile–water solution and analyzed using high-performance liquid chromatography. The MWCNTs/NaDC fiber exhibited a response two to six times that of a commercial fiber for phenols. The hydrogen interactions with the analytes and the large surface area of the MWCNTs facilitated analyte adsorption with good selectivity and reproducibility. Under the optimum extraction conditions, the MWCNTs/NaDC fiber had a good linear range (1–100 ng/mL), repeatability for the extractions (relative standard deviation = 4.9%–7.1%, n = 3), low limits of detection (0.15–0.30 ng/mL), and satisfactory recoveries (80.3%–95.4%). This is an accurate and cost-effective pretreatment method.