مشخصات پژوهش

Cadmium (Cd) is used in many industrial processes, such as a constituent of easily fusible alloys, soft solder, electroplating and deoxidizer in nickel plating, engraving processes, electrodes for vapor lamps, photoelectric cells, and nickel-cadmium storage batteries. Although essential function of cadmium on human body is not clearly known, it may cause toxic effects even at very low doses. Cadmium acts as inhibitor of sulphydryl enzymes and has an affinity for other ligands in cells such as hydroxyl, carboxyl, phosphatyl, rysteinyl and histidyl side chains of proteins. In this research, a ZnO@Ag2O@Fe3O4 nonocomposite as an innovative solid phase extraction agent was developed for the selective exffaction and preconcentration of trace levels of cadmium ions prior to determination by flame atomic absorption spectrometry. The structure and morphology of the synthesized nano-sorbent were characterized using powder X-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy.T he as-prepared nano-sorbent possesses the magnetism properry of Fe:O+ nano-particles that makes it easily manipulated by a magnet. Several factors affecting the exffaction of the analyte were investigated and optimized. Under optimum conditions, the calibration graph was linear in the range of 0.1-10 ng ml-r with a correlation coefficient of 0.9918. The limit of detection and enrichment factor for cadmium were 0.03 ng mL-1 and 200, respectively.T he intra- and inter-day relative standard deviations for six replicate determinations of 4 ng mL-1 were 1.8 and 2.6 o/0r,e spectively.T he maximum sorption capacity of the sorbent for cadmium was 48 mg g-1. The method was validated by the analysiso f the standard referencem aterial NIST SRM 1643e, and successfullya pplied to the pre-concentration and determination of cadmium in several water samples with recoveries in the range of 9B-1.02o /of or the spikeds amples.