مشخصات پژوهش

Zinc is an essential trace element in nutrition of all animals and human and it plays a number of important physiological and biological roles. It works with many enzyme systems, both as metallo-enzyme and enzyme-activator, that make genetic material, cell replications, protein synthesis, digest food, metabolize carbohydrate and acts as a cofactor in numerous enzymes [1]. Deficiency of zinc leads to retarded growth, lower feed efficiency, inhibits the general well-being, causes ulcers, scaling of the skin, besides affecting the bones and joints. Moreover, metabolic disorders of zinc have now been closely associated with a number of neurological diseases, such as Alzheimer‘s disease, Parkinson‘s diseases, epilepsy and hypoxia-ischemia [2]. In this work, magnetic chitosan nanocomposite was synthesized by a simple co-precipitation method [3]. Chitosan was selected in this research due to its excellent properties such as nontoxicity, low cost and chelating effects. Moreover, nickel(II) oxide was used as a magnetic agent in this nanocomposite, because of the more stability in acidic solutions and facility elution of the sorbent [4]. The morphological properties of the nanosorbent were characterized by FT-IR, XRD and SEM. In the second step, the synthesized nanocomposite was used as nanosorbent in the solid phase extraction and pre-concentration of trace amount of zinc ions from aqueous solutions. Several parameters affecting the extraction efficiency such as pH, sorption time, amount of nanosorbent and sample volume were studied and optimized. Under optimum conditions, pre-concentration factor, limit of detection and relative standard deviation are 100, 0.25 μg L‒1 and 2.89 %, respectively. The calibration graph is linear in the range of 0.02‒1.5 μg L‒1 with a correlation coefficient of 0.990. Method validation was carried out by analysis of the standard reference material, NIST SRM 1549. The method was successfully applied to determine zinc in water and milk samples.