A nanocomposite consisting of etched multiwalled carbon nanotubes, amino-modified metal-organic framework UiO-66 and polyaniline for preconcentration of polycyclic aromatic hydrocarbons prior to their determination by HPLC.

A polyaniline composite doped with etched multi-walled carbon nanotubes and UiO-66-NH was prepared by electropolymerization. It was used as a sorbent to extract the polycyclic aromatic hydrocarbons (PAHs) phenanthrene, fluoranthene and pyrene. Its surface morphology, crystal structure and capability of adsorbing PAHs were characterized by scanning electron microscopy, X-ray photoelectron spectrometry, Fourier transform infrared spectrometry and zeta potentiometry. The π stacking and anion-π interactions are shown to play dominant roles in the sorption mechanism. Coupled with high performance liquid chromatography, the composite-modified fiber was applied to detect PAHs in lake water samples by direct immersion extraction. The method excels by (a) wide linear range (0.05-20 ng mL), (b) low limits of detection (10 pg mL), (c) satisfactory recovery from spiked samples (84.7-113.8%), and (d) good reproducibility (relative standard deviations of <6.5%). The method is superior in terms of costs and reproducibility compared to some pretreatment methods with mass spectrometric detection. Graphical abstractSchematic representation for interaction between PANI-etched MWCNT/UiO-66-NH and polycyclic aromatic hydrocarbons (phenanthrene, fluoranthene, pyrene).