Oxidized multiwalled carbon nanotubes as a novel solid-phase microextraction fiber for determination of phenols in aqueous samples

A simple and environmentally friendly method for determination of seven phenols using solid-phase microextraction (SPME) coupled to high-performance liquid chromatography (HPLC) has been developed. Several materials were used as stationary phase of SPME fibers and an oxidized multiwalled carbon nanotubes material was found to be effective in carrying out simultaneous extraction of phenols in aqueous samples. Compared with the widely used commercially available SPME fibers, this proposed fiber had much lower cost, longer lifetime (over 150 times), shorter analysis time (30 min of extraction and 3 min of desorption time) and comparable or superior extraction efficiency for the investigated analytes. The extraction and desorption conditions were evaluated and the calibration curves of seven phenols were linear (R2 ≥ 0.9908) in the range from 10.2 to 1585 ng mL−1. The limits of detection at a signal-to-noise (S/N) ratio of 3 were 0.25–3.67 ng mL−1, and the limits of quantification calculated at S/N = 10 were 0.83–12.25 ng mL−1 for these compounds. The possibility of applying the proposed method to environmental water samples analysis was validated.