Ultrasonic assisted synthesis of a novel ternary nanocomposite based on carbon nanotubes/zeolitic imidazolate framework-67/polyaniline for solid-phase microextraction of organic pollutants

In the present research, a new nanoporous composite coating of polyaniline (PANI), modified multi-walled carbon nanotubes (MWCNTs), and zeolitic imidazolate frameworks (ZIF) was successfully fabricated by a layer by-layer strategy through electrodeposition method on a stainless steel wire and ultrasonic-assisted. The optimization of the coating was done with design expert 10.0.7.0 software, while the crucial factors were optimized using a central composite design (CCD). The characteristics of the nanocomposite were examined by field emission-scanning electron microscopy (FE-SEM) and Fourier transform-infrared spectroscopy (FT-IR). The applicability of this home-made coating fiber was assessed for the headspace solid-phase microextraction (HSSPME) of trace amounts of some organic pollutants in aqueous samples followed by gas chromatography-flame ionization detector (GC-FID). The significant parameters affecting the extraction efficiency, such as desorption and sorption conditions along with ionic strength, were also investigated. Validation experiments showed that the optimized method has wide linear ranges from 0.005 to 1000 mu g L-1, very low limits of detection (0.0003-0.0008 mu g L-1) and excellent repeatability (0.2-9.7%). The relative recoveries obtained by spiking the target analytes in aqueous samples were in the range 83.4-111.2%. The combination of modified CNTs, ZIF-67, and aniline in the nanocomposite create attractive opportunities for the development a new coating fiber with a porous structure, strong adhesion to the surface of the wire, excellent thermal stability, long lifespan and high extraction efficiency suggesting the potential of this SPME fiber for routine analysis in real samples.