A simple and fast method based on functionalized magnetic nanoparticles for the determination of Ag(i), Au(iii) and Pd(ii) in mine stone, road dust and water samples

Abstract

Murexide functionalized magnetic nanoparticles were employed, herein, as an efficient sorbent in combination with flame atomic absorption spectrometry, for the rapid extractive preconcentration and determination of trace amounts of silver, gold and palladium. In this regard, the design of the experiments approach, in combination with response surface methodology was applied to optimize the affecting parameters (pH value, sorption time, sorbent dosage elution time, eluent type and composition). The best extraction performance was achieved under the following conditions: 10 mg sorbent, 5.0 min for sorption time, a pH value of 3.1, 3.0 min elution time and 4.4 mL 0.5 mol L^−l thiourea in 1 mol L^−l HCl solution as the eluent. Under the optimal conditions, the limits of detection (LODs) were 0.15, 0.6 and 0.25 μg L⁻¹ for Ag(I), Au(III) and Pd(II), respectively. The precision of the proposed method was evaluated by determining the relative standard deviations and was found to be less than 10%. The accuracy of the method was investigated by analyzing a certified reference material (Ore polymetallic gold Zidarovo-PMZrZ (206 BG 326)). An interference study revealed that there are no interferences from commonly occurring cations and anions in the extraction recovery of the target analytes. The sorption capacities were obtained in the range of 34–50 mg g⁻¹. Ultimately this nanosorbent was successfully applied to the rapid extraction of trace quantities of Ag(I), Au(III) and Pd(II) ions in different real samples with satisfactory results.