The Construction Of Electrochemical Sensor Based On Metal Oxide And Its Analytical Application

Metal oxide is of great interest as they are cheaper than noble metal,have large surface area,have wide energy band gap and can improve the electrochemical performance of materials,therefore Metal oxide is employed widely in gas sensors,Photocatalysts,supercapacitors,lithium-ion batteries,and electrochemical detection.Graphene?GN?,a new carbon material composed of single layer of carbon atoms in a closely packed into a honeycomb two-dimensional lattice,is a promising support material with high charge transport mobility.However,graphene is apt to aggregate.To overcome the obstacle,various surfactants have been introduced to the graphene surface.In the present work,the sodium dodecyl sulfonate?SDS?and poly?sodium 4-styrenesulfonate??PSS?functionalized graphene was as substrate materials,by combining the properties of metal oxide and functional graphene,we fabricate three electrochemical sensors.Electrochemical reaction mechanism of analyte?pharmaceutical sample and azo dye?was discussed in detail,and the sensors were successfully applied for the analysis of real samples.1.A sensitive sodium dodecyl sulfonate functionalized graphene hybrid Sn O2 nanoparticles composite modified glassy carbon electrode for detecting daphnetinIn this work,a sensitive electrochemical sensor based on sodium dodecyl sulfonate?SDS?functionalized graphene hybrid SnO₂ nanoparticles?SDS-GN/SnO₂?composite was fabricated via one-pot synthesis.The SDS-GN/SnO₂ nanocomposite significantly increased the redox activity of daphnetin.The nanocomposite was characterized by UV-vis detection,the FT-IR spectrum,X-ray diffraction?XRD?patterns and transmission electron microscope?TEM?.Cyclic voltammetry?CV?and differential pulse voltammetry?DPV?measurements were used for the detection of daphnetin.Under the optimal conditions,the oxidation peak currents of daphnetin increased proportionally to the concentration within the range of 0.03–1.0 ?mol L^-1 and 1.0–8.0 ?mol L^-1,and the limit of detection was 8.0 nmol L^-1.The proposed modified electrode was highly sensitive and was successfully applied to determine daphnetin in the pharmaceutical sample with satisfactory recoveries.2.A novel electrochemical sensor based on WO₃ nanorods-decorated poly?sodium 4-styrenesulfonate?functionalized graphene nanocomposite modified electrode for detecting of puerarinIn this work,an electrochemical sensing platform was fabricated based on composition of poly?sodium 4-styrenesulfonate??PSS?,graphene?GN?and WO₃ nanorods on glassy carbon electrode?GCE?.The PSS-GN/WO₃ nanocomposite significantly increased the oxidative activity of puerarin due to the individual merit and mutual effect of PSS-GN and WO₃ nanorods which improved the performance of the electrochemical sensor with high sensitivity.Cyclic voltammetry?CV?and linear sweep voltammetry?LSV?measurements were used for the detection of puerarin.Under the optimal conditions,the oxidation peak currents of puerarin increased proportionally to the concentration within the range of 0.06–0.6 ?mol L^-1 and 0.6–6.0 ?mol L^-1,and the limit of detection was 0.04 ?mol L^-1.The proposed modified electrode was highly sensitive and was successfully applied to determine puerarin in the pharmaceutical sample and human plasma with satisfactory recoveries.3.Electrochemical sensor based on poly?sodium 4-styrenesulfonate?functionalized graphene and Co₃O₄ nanoparticle clusters for detection of amaranth in soft drinksIn this work,a new sensitive electrochemical sensor based on poly?sodium 4-styrenesulfonate??PSS?functionalized graphene and Co₃O₄ nanoparticle clusters?PSS-GN/Co₃O₄?ternary composite was fabricated via two-step synthesis.The PSS-GN/Co₃O₄ nanocomposite significantly increased the oxidative activity of amaranth due to the individual merit and mutual effect of PSS-GN and Co₃O₄ nanoparticle clusters which improved the performance of the electrochemical sensor with high sensitivity.Cyclic voltammetry?CV?and linear sweep voltammetry?LSV?measurements were used for the detection of amaranth.Under the optimal conditions,the oxidation peak currents of amaranth increased proportionally to the concentration within the range of 0.01–1.0 ?mol L^-1 and 1.0–6.0 ?mol L^-1,and the limit of detection was 4.0 nmol L^-1.The proposed modified electrode was highly sensitive and was successfully applied to determine amaranth in the soft drinks with satisfactory recoveries.By the individual merit and mutual effect of metal oxide and functional graphene,we fabricate three electrochemical sensors and apply to analyze.In the present work,we further prove that the excellent properties of nano metal oxide on the electrochemical detection and broaden its application scope.