▎ 摘　　要

This study describes the synthesis of graphene oxide-modified magnetite (rGO/ Fe3O4) and its use as an electrochemical sensor for the quantitative detection of hemoglobin (Hb). rGO is characterized by a 2 theta peak at 10.03 degrees in its X-ray diffraction, 1353 and 1586 cm(-1) vibrations in Raman spectroscopy, while scanning electron microscopy coupled with energydispersive spectroscopy of rGO and rGO/Fe3O4 revealed the presence of microplate structures in both materials and high presence of iron in rGO/Fe3O4 with 50 wt %. The modified graphite pencil electrode, GPE/rGO/Fe3O4, is characterized using cyclic voltammetry. Higher electrochemical surface area is obtained when the GPE is modified with rGO/Fe3O4. Linear scan voltammetry is used to quantify Hb at the surface of the sensor using ferrocene (FC) as an electrochemical amplifier. Linear response for Hb is obtained in the 0.1-1.8 mu M range with a regression coefficient of 0.995, a lower limit of detection of 0.090 mu M, and a limit of quantitation of 0.28 mu M. The sensor was free from interferents and successfully used to sense Hb in human urine. Due to the above-stated qualities, the GPE/rGO/Fe3O4 electrode could be a potential competitive sensor for trace quantities of Hb in physiological media.