Construction And Application Of Electrochemical Sensors Based On Graphene Nanomaterials

Electrochemical sensors have been widely applied to the fields of medical diagnosis,environmental detection and so on,due to its unique advantage,such as easy operation,low cost,good stability and high sensitivity.However,the development of electrochemical sensors were significantly restricted by the electrode materials,because of much disadvantage,such as high cost,heavy metal containing and poor electrochemical activity.Therefore,in the thesis,on the basis of the review of development electrochemical sensor,series of graphene nanomaterials with excellent electrochemical properties have been fabricated and applied to construction of electrochemical sensors.The main experimental contents were described as follows:Firstly,the reduced graphene oxide-zinc oxide(RGO-Zn O)composite was fabricated by a spontaneous reduction of graphene oxide(GO)on zinc slice.The results showed that the existence of Zn O particles in electrochemical sensor(RGO-Zn O/GCE),enhanced the electroactive surface area and sensitivity for simultaneous electrochemical detection of dopamine(DA),ascorbic acid(AA)and uric acid(UA).The sensors exhibited three well-resolved voltammetric peaks(?EAA-DA=236 m V,?EDA-UA=132 m V,?EAA-UA=368 m V),wide linear range(50–2350 ?M,1–70?M,3–330 ?M)and lower detection limits(3.71 ?M,0.33 ?M and 1.08?M)for detection of AA,DA and UA.The as-prepared RGO-Zn O/GCE biosensor was successfully applied to the detection of AA,DA and UA in real plasma and urine samples.Further,the three-dimensional reduced graphene oxide(3DRGO)architectures were obtained by washing RGO-Zn O with diluted hydrochloric acid.Under physiological condition(p H=7.4),the electrochemical sensor(3DRGO/GCE)was fabricated and successfully applied to detection of chloramphenicol(CAP)in eye drops.The liner detection range was 1–113u M and the detection limit was 0.15 ?M,respectively.Secondly,the chlorine-doped reduced graphene oxide(Cl-RGO)was fabricated by reduction of GO with concentrated hydrochloric acid at 120?,under nitrogen atmosphere.Theelectrochemical sensor for CAP was constructed by using Cl-RGO as electrode materials,.The liner detection range is 1–46 ?M and detection limit is 0.47 u M.Moreover,it exhibited excellent selectivity,stability,reproducibility and further applied to the detection of CAP in eye drops.In addition,phosphorus-doped graphene(P-RGO),boron and phosphorus co-doped graphene(BP-RGO)were fabricated with triphenylphosphine and boron trifluoride etherate as reductants by hydrothermal method,respectively.The as-prepared P-RGO and BP-RGO were characterized by scanning electron microscopy(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).It was revealed that the electrochemical activity of graphene was strongly improved by introducing hetero-atom.The electrochemical sensors,constructed based on P-RGO and BP-RGO were applied to simultaneous detection of AA,DA,UA and 4-acetamidophenol(AP)as well as detection of hydrogen peroxide(H2O2),respectively.