Separation and preconcentration of trace amounts of silver (I) in water samples based on dithizone modified sodium dodecyl sulfate-coated Fe3O4 nanoparticles

Complete text of publication follows. Using magnetic nanoparticles for separation and preconcentration in analytical chemistry is opening a new methodology that is faster, simpler and more precise than old ones. In this work, a simple and reliable solid-phase extraction method has been developed to selectively separate and preconcentrate trace amounts of silver (I) from aqueous samples for subsequent measurement by atomic absorption spectrometry. Silver ion was adsorbed quantitatively from aqueous solution onto magnetic nano-adsorbent with dithizone (DTZ) immobilized on sodium dodecyl sulfate (SDS)-coated Fe3O4 nanoparticles (DTZ-S-IONPs). SDS as a surfactant makes admicelle on the surface of Fe3O4 nanoparticles, which allows the metal complexing agent of DTZ, to be immobilized in its hydrocarbon cores. This assemble, as a chelating adsorbent, has made the separation and preconcentration of silver ion possible. It is shown that the novel magnetic nano-adsorbent is quite efficient for the adsorption and desorption of silver (I) at 25 deg C. Different parameters such as pH, temperature, ionic strength, equilibrium time, type and least amount of stripping solution were optimized. The effect of some co-existing ions on the determination was investigated. An aqueous solution containing thiourea has been used in order to selectively desorb the adsorbed silver ion from the surface of the adsorbent. No serious interferences have been observed due to the presence of another species in the sample. The separation selectivity of the adsorbent for other cations was studied. To improve this, EDTA was added to the source solution before applying to the DTZ-S-IONPs as chelating adsorbent. The procedure was applied for analysis of two real samples. The method is simple and inexpensive. This research was supported by the Department of Chemistry and Nanoscience and Nanotechnology Research Laboratory (NNRL) Payame Noor University of Sirjan.