Magnetic solid-phase extraction to preconcentrate ultra trace amounts of lead(ii) using modified-carbon nanotubes decorated with NiFe2O4 magnetic nanoparticles

Abstract

Here, multiwalled carbon nanotubes decorated with NiFe₂O₄ nanoparticles were synthesized by a simple reaction. Then, the nanoparticles were modified with 3-(trimethoxysilyl)-1-propanthiol. The modified-multiwalled carbon nanotubes decorated with NiFe₂O₄ nanoparticles were applied as a solid-phase extraction (SPE) sorbent for the extraction of ultra trace amounts of Pb(II) from water samples. Detection in this technique was performed by flame atomic absorption spectrometry. The influences of effective parameters on the extraction efficiency were studied. The best results were obtained at pH 6.0 (acetate–borate buffer) with 2.0 mL eluent solution of 1.5 mol L⁻¹ nitric acid and an extraction time of 30 min. The detection limit was 0.5 ng mL⁻¹ Pb(II) with a precision of 2.3–4.1%. The effects of matrix ions present in natural waters and some transition metals on the recoveries of the analyte ions were also examined in model solutions. Finally, the proposed method was used for the measurement of Pb(II) in water from the Shiraz Khoshk river (Shiraz, Iran), food, and industrial waste water from Isfahan's Mobarakeh Steel Company.