Application of magnetic nanocomposite modified with a thiourea based ligand for the preconcentration and trace detection of silver(I) ions by electrothermal atomic absorption spectrometry

In this study, a novel and simple modified magnetic nanocomposite was investigated for the analysis of trace amount of silver(I). For this purpose, the magnetically activated carbon/gamma-Fe2O3 (AC/gamma-Fe2O3) nanocomposite was successfully synthesized and modified with a symmetrical thiourea derivative, 4,4'-bis-(3-phenylthiourea)diphenyl methane (BPDM). The different experimental factors affecting the preconcentration and detection of the analyte ions were studied in detail. The effects of foreign ions on the extraction of Ag(I) ions were also investigated. Under the optimum conditions, a sensitive response to Ag(I) within a wide concentration range (0.01-28 mu g L-1) was achieved. The limit of detection (LOD, 3 S-b/m) was 2.3 ng L-1. The maximum adsorption capacity of the novel magnetic adsorbent for Ag(I) was found to be 32.6 mg L-1. An enrichment factor (EF) of 125 was obtained by the ratio of the highest sample volume for analyte (125 mL) and the lowest final eluent volume (1 mL). The developed method was successfully applied to monitoring silver in water samples and the certified reference material. The procedure exhibited some advantages, such as simplicity, rapidity, high sensitivity, and low cost. In addition, the mechanism of silver extraction by modified nanocomposite was proposed. (C) 2016 Elsevier B.V. All rights reserved.