Solid phase extraction of Pb(ii) and Cd(ii) ions based on murexide functionalized magnetic nanoparticles with the aid of experimental design methodology

Abstract

This work describes a novel sorbent based on murexide functionalized magnetic nanoparticles and its application in the preconcentration of Pb(II) and Cd(II) ions. The parameters affecting preconcentration were optimized by a Box–Behnken design through a response surface methodology. Three variables (extraction time, magnetic sorbent amount, and pH value) were selected as the main factors affecting sorption, while four variables (type, volume and concentration of the eluent; elution time) were selected for investigating the elution step in the optimization study. These values were 14 mg, 11 min, 6.5, H₂SO₄, 3 mL, 1.5 mol L^−l H₂SO₄ solution, and 6.7 min, for the amount of magnetic sorbent, extraction time, pH of extraction, type, volume, and concentration of the eluent, and elution time, respectively. Following the sorption and elution steps, Pb(II) and Cd(II) ions were quantified by flame atomic absorption spectrometry. The limits of detection (LODs) were 1.0 and 0.1 μg L⁻¹ for Pb(II) and Cd(II), respectively. The relative standard deviations of the method were less than 6.9%. The sorption capacities of this new sorbent were 125 and 98 mg g⁻¹ for Pb(II) and Cd(II), respectively. Ultimately, this nanosorbent was successfully used for the rapid extraction of trace quantities of Pb(II) and Cd(II) ions in different water and food samples and satisfactory results were obtained.