Trace determination of lead(II) ions by using a magnetic nanocomposite of the type Fe3O4/TiO2/PPy as a sorbent, and FAAS for quantitation

The authors describe a magnetic nanoadsorbent consisting of magnetite nanoparticles coated first with titanium dioxide and then with polypyrrole (PPy). It is shown to be a viable material for magnetic solid-phase extraction of trace amount of Pb(II). The magnetic titanium dioxide nanoparticles were synthesized first and then modified with PPy via in-situ electropolymerization. The properties, morphology, and composition of the sorbent were characterized by FTIR, scanning electron microscopy, energy-dispersive X-ray analysis and vibrating sample magnetometry. The effects of pH value, extraction time, type and concentration of eluent, and of sample volume were optimized. Under the optimum conditions, the limit of detection (for S/N = 3) is 0.28 mu gai...L-1. The maximum adsorption capacity of the adsorbent is 126 mgai...g(-1) of Pb(II). The accuracy of the method was investigated by analysis of a Certified Reference Material and the obtained value (0.119 mu gai...g(-1)) was in good agreement with the certified value (0.120 mu gai...g(-1)). The method was successfully applied to the determination of Pb(II) in a gastropod and spiked environmental and marine water samples. It gave recoveries in the range from 94.4 to 103.1%.