Innovative fabrication of the flower-like nanocomposite coating on a nitinol fiber through Fenton's oxidation for selective and sensitive solid-phase microextraction

A novel flower-like nanostructure was successfully in situ fabricated on the surface of nitinol wire through Fenton's oxidation for the first time. It was found that the densely immobilized coating on the surface of the nitinol fiber was composed of nickel and titanium oxide nanocomposite (NiO/TiO2NC). The NiO/TiO2NC coated fiber was used to extract aromatic compounds coupled with high performance liquid chromatography (HPLC) with UV detection and exhibited excellent extraction efficiency for polycyclic aromatic hydrocarbons (PAHs) with larger delocalized pi-system among the studied analytes. Important factors affecting extraction efficiency of PAHs were examined. Under the optimized conditions, the calibration curves were linear in the range from 0.05 to 500 mu g L-1 with correlation coefficients of R-2 >= 0.999, and the lowest limit of detection of 0.006 mu g L-1 was achieved for benzo[a]pyrene. Furthermore, the intra-day and inter-day precisions for the single fiber varied from 4.69% to 5.97% and from 5.28% to 6.32% for five replicates of PAHs at the spiking level of 50 mu g L-1, respectively. The fiber-to-fiber precision for five fibers prepared in different batches ranged from 6.19% to 835%. The developed method was successfully applied to concentration and determination of target PAHs from real environmental water samples. Moreover, this novel nitinol-based fiber exhibited long lifespan. Therefore, the proposed fiber can be used as a promising candidate for a conventional fused silica-based fiber in SPME. (C) 2016 Elsevier B.V. All rights reserved.