Simultaneous Functionalization and Reduction of Magnetic Graphene Oxide by L-Histidine and its Application for Magnetic Separation/Preconcentration of Antioxidant Trace Elements.

In the present study, for the first time, the magnetic graphene oxide was simultaneously functionalized and reduced with the aim of imidazole-based L-histidine amino acid (rGO/Fe3 O4 -histidine). The prepared nanocomposite was characterized by field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy, and vibrating sample magnetometer. The synthesized rGO/Fe3 O4 -histidine nanosheets were implied for solid phase extraction of ultra-trace amounts of Zn2+ , Cu2+ , and Mn2+ from biological samples prior to ICP-OES determination. The calibration curves were linear in the concentration ranges of 0.4-182.0, 0.4-215.0, and 0.2-168.5 μg L-1 for Zn2+ , Cu2+ , and Mn2+ , respectively. The limits of detection were 0.12, 0.10, and 0.04 μg L-1 for Zn2+ , Cu2+ , and Mn2+ , respectively. The relative standard deviations (RSDs) at 50.0 μg L-1 for single-sorbent repeatability and sorbent-to-sorbent reproducibility were less than 6.7 and 9.2% (n = 5), respectively. The accuracy of the method was confirmed by the analysis of a serum quality control material (QCM, Seronorm™ Human Serum REF NO 203105) and hair certified reference material (CRM, Human Hair IAEA-086).