Selective extraction and sensitive determination of mercury (II) ions by flame atomic absorption spectrometry after preconcentration on an ion-imprinted polymer-coated maghemite nanoparticles

摘要

An ion-imprinted polymer-coated maghemite nanoparticle adsorbent for selective extraction of Hg(II) ion was synthesized. The polymerization was carried out by the new mercaptoethylamino monomer as the functional monomer, ethylene glycol dimethacrylate as the crosslinking agent and ammonium persulfate as the initiator in the presence of Hg(II) ions as the template. The synthesized nanoparticles were characterized using FT-IR, XRD and TEM analysis. The effects of various factors that may affect the solid-phase extraction of Hg(II) (i.e. pH, adsorbent dosage, contact time) and the preconcentration factor (i.e. initial sample volume, type and volume of the desorbing solvent) were optimized using one-at-a-time method. The maximum adsorption capacity was obtained as 72.8 mg g(-1). Compared with the non-imprinted polymer-coated nanoparticles, the synthesized ion-imprinted polymer-coated nanoparticles had higher selectivity for Hg(II). The detection limit was found to be 4.1 mu g L-1 for an initial sample volume of 200.0 mL using flame atomic absorption spectrometry. The developed method was successfully applied to the determination of trace amounts of mercury in tap water and wastewater samples.