Synthesis and application of a nanoporous ion‐imprinted polymer for the separation and preconcentration of trace amounts of vanadium from food samples before determination by electrothermal atomic absorption spectrometry

A vanadium ion‐imprinted polymer was synthesized in the presence of V(V) and N‐benzoyl‐N‐phenyl hydroxyl amine using 4‐vinyl pyridine as the monomer, ethylene glycol dimethacrylate as the cross linker and 2,2’‐azobis(isobutyronitrile) as the initiator. The imprinted V(V) ions were completely removed by leaching the polymer with 5 mol/L nitric acid, and the polymer structure was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The ion‐imprinted polymer was used as the sorbent in the development of the solid‐phase extraction method for V(V) prior to its determination by electrothermal atomic absorption spectrometry. The maximum sorption capacity for V(V) ions was 26.7 mg/g at pH 4.0. Under the optimum conditions, for a sample volume of 150.0 mL, an enrichment factor of 289.0 and a detection limit of 6.4 ng/L were obtained. The developed method was successfully applied to the determination of vanadium in parsley, zucchini, black tea, rice, and water samples.