A solid-phase extraction method using Pb²⁺ion-imprinted polymer (Pb²⁺-IIP) nanoparticles combined with flame atomic absorption spectrophotometry (FAAS) was developed for the preconcentration and trace monitoring of lead ions in environmental samples. The Pb²⁺-IIP nanoparticles were obtained by precipitation polymerization of 4-vinylpyridine (the functional monomer), ethylene glycol dimethacrylate (the cross-linker), 2,2′-azobisisobutyronitrile (the initiator), 4-(2-pyridylazo) resorcinol (the lead-binding ligand), and lead ions (the template ion) in acetonitrile solution. The Pb²⁺-IIP nanoparticles were characterized by Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TGA/DTA), and by scanning electron microscopy (SEM). Different affecting parameters on the adsorption and desorption of this solid-phase extraction process were evaluated and optimized. Under the optimized conditions, the detection limit for the proposed method was found to be 0.9 μg L⁻¹, while the relative standard deviation (RSD) for five replicate measurements was calculated to be <4 %. For proving that the proposed method is reliable, a range of food and water samples with different and complex matrices was used.

A new dispersive liquid–liquid microextraction, magnetic stirrer induced dispersive ionic-liquid microextraction (MS-IL-DLLME) was developed to quantify the trace level of vanadium in real water and food samples by graphite furnace atomic absorption spectrometry (GFAAS). In this extraction method magnetic stirrer was applied to obtained a dispersive medium of 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6] in aqueous solution of (real water samples and digested food samples) to increase phase transfer ratio, which significantly enhance the recovery of vanadium – 4-(2-pyridylazo) resorcinol (PAR) chelate. Variables having vital role on desired microextraction methods were optimised to obtain the maximum recovery of study analyte. Under the optimised experimental variables, enhancement factor (EF) and limit of detection (LOD) were achieved to be 125 and 18ngL−1, respectively. Validity and accuracy of the desired method was checked by analysis of certified reference materials (SLRS-4 Riverine water and NIST SRM 1515 Apple leaves). The relative standard deviation (RSD) for 10 replicate determinations at 0.5μgL−1 of vanadium level was found to be <5.0%. This method was successfully applied to real water and acid digested food samples.

This paper describes a novel sorbent based on 4-(2-pyridylazo) resorcinol functionalised magnetic nanoparticles and its application for the extraction and pre-concentration of trace amounts of Cu(II) and Pb(II) ions. The nanosorbent was characterised by Fourier transform infrared spectroscopy, X-ray powder diffraction, thermal analysis, elemental analysis and scanning electron microscopy. The effects of various parameters such as pH, sorption time, sorbent dosage, elution time, volume and concentration of eluent were investigated. Following the sorption and elution of analytes, Cu(II) and Pb(II) ions were quantified by flame atomic absorption spectrometry. The limits of detection were 0.07 and 0.7 μg l ⁻¹ for Cu(II) and Pb(II), respectively. The relative standard deviations of the method were less than 7%. The sorption capacity of this new sorbent were 92 and 78 mg g ⁻¹ for Cu(II) and Pb(II), respectively. Finally this nanosorbent was applied to the rapid extraction of trace quantities of Cu(II) and Pb(II) ions in different real samples and satisfactory results were obtained.