using of fe3o4-graphene oxide- modified chitosan with melamine magnetic nanocomposite in magnetic dispersive solid phase microextraction of cr(vi) ions in aquatic samples

Abstract: chromium as a heavy metal enters to the environment with human activities from various industries such as leather tanning, wood treatments or metallurgy industries. hexavalent chromium is a very toxic species with high risks to human health and the environment. the presence of such harmful pollutants demands proper separation and enrichment methods to increase the detection power of the analytical instruments [1]. in recent years, magnetic solid-phase extraction (mspe) based on iron oxide nanoparticles have received special attention as adsorbents to high-efficiently extract heavy metals such as chromium (vi). in the present study, biocompatible, effective and magnetic graphene oxide modified chitosan with melamine nanocomposites (go-fe3o4-cs-ma) were synthesized [2]. the structure and morphology of synthesized nanocomposites was characterized using ft-ir, sem, edx, xrd, dls, zeta- potential, vsm and tga. the application of synthesized nanocomposites for magnetic dispersive solid phase extraction of chromium (vi) from aqueous samples was investigated. the chromium determination is based on the complex formation reaction of cr(vi) with 1,5-diphenylcarbazide. in order to achieve high enrichment factors and reduce the detection limit of the method, various parameters were studied and optimized. optimal values for the adsorbent amount, adsorption and desorption time, salt percentage and ph were 20 mg, 5 minute, 0% and 4, respectively. also, 1 ml of sodium hydroxide 0.01 m was selected as the optimal desorption solvent. the suggested method was linear (r2 = 0.9993) over a range of 0.05-0.5 mg l-1. the limit of detection was 0.015 mg l-1. finally, the applicability of the proposed method was evaluated by analysis of the hexavalent chromium in the industrial effluent of charmshahr tabriz as well as some surface waters. the percentage of recoveries was in the range of 101-91% and the percentage of relative deviation was 2-6%.