Fabrication And Application Of Ferrocene-Based Hyperbranched Polymer/Graphene Sensitizing Sensor

Ferrocene based hyperbranched polymer(HPAE-Fc)were used as a substrate,which has redox signal of ferrocene to fabricate a sensitizing electrochemical sensor.HPAE-Fc modified electrode was physico-chemically modified by graphene(GR)and gold nanoparticles(Au),so that electrochemical sensing sensors were fabricated with high stability and sensitivity.The sensing sensors had excellent electrochemical performance of ferrocene,the unique three-dimensional structure and film-forming properties of hyperbranched polymers,the excellent electron transport and surface activity of graphene and gold nanoparticles.The sensing sensors were applied to detect cholesterol and dichlorvos(DDVp),and it was proposed to realize the real-time detection of the sensor and to further study the sensitizing mechanism of the sensor.The specific research contents are as follows:Laminated Ferrocene based hyperbranched polymer/GR sensor(HPAE-Fc/ GR/GCE),Monolayer Ferrocene based hyperbranched polymer-graphene sensor(M-HPAE-Fc-GR/GCE)and Nano-gold/Ferrocene based hyperbranched polymer-graphene composite sensitizer sensor(Au/HPAE-Fc-GR/GCE)were constructed by using the drop coating method and the electrodeposition method.The electrochemical characteristics,stability and influencing factors of the sensor were investigated by cyclic voltammetry,differential pulse voltammetry and AC impedance method.At the same time,the sensor was applied to the detection of cholesterol and dichlorvos.The reproducibility of the electrode,sensitivity and resistance to interference were analyzed when the substance was detected.The sensitizing mechanism of the graphene and gold nanoparticles to the sensor was also explored.The HPAE-Fc/GR/GCE was constructed using the modified method of layered superposition.HPAE-Fc/GR material was modified on the surface of glassy carbon electrode,improving the electrode surface activation energy,reducing the electrode surface resistance.HPAE-Fc/GR/GCE had a good response to cholesterol,and the response current was linear with the concentration of cholesterol in the range of 7.69 ×10-5~2.28×10-3 mol·L-1.The detection limit was 8.878×10-6 mol·L-1.The reproducibility of sensor was 90.5 %,the relative standard deviation was 0.095,the stability of sensor reached 91.428 %,the detection error of cholesterol was less than 5 %,HPAE-Fc/GR/GCE showed good anti-interference.The M-HPAE-Fc-GR/GCE was constructed by using HPAE-Fc and GR as composite materials with chemical bonding and adsorption.The response current of HPAE-Fc-GR composites was significantly higher than that of HPAE-Fc/GR materials.The results showed that the M-HPAE-Fc-GR/GCE had a good response to dichlorvos.The response current was linear with the dichlorvos concentration in the range of 7.47~213.14 ?mol·L-1.The detection limit was 3.35 ?mol·L-1;the reproducibility of sensor is 91.5 %,the relative standard deviation was 0.085,the stability of sensor was 92.848 %,and the error caused by the disturbance to the dichlorvos was controlled within 5 %,indicating that M-HPAE-Fc-GR/GCE had reproducibility,stability and anti-interference.Au/HPAE-Fc-GR/GCE with Double Sensitizing Properties was manufactured using modified Nanoparticles and HPAE-Fc-GR Composite,because nano-gold had a unique catalytic and electron transfer capability.The detection range is 1.392 ~ 87.027 ?mol·L-1,the detection limit was reduced to 0.6 ?mol·L-1,which indicated Au/HPAE-Fc-GR/GCE showed a higher sensitivity than the previous sensor.The reproducibility,stability and anti-interference of sensor were higher than HPAE-Fc/ GR/GCE and M-HPAE-Fc-GR/GCE.The lamellar structure of graphene maintains the electrode surface with a high specific surface area,increased the adsorption capacity of the material and its electrical conductivity to expand the electrical signal,resulting in improved sensitivity.After the combination of gold nanoparticles and graphene,the conductivity was further improved and the activation energy of the reaction is reduced.The synergistic sensitization effect of the two nanoparticles made the sensor more sensitivity.The Ferrocene-based hyperbranched polymer/graphene sensitizing sensor had good stability and anti-interference.Under the synergistic sensitization of HPAE-Fc and Au and GR,the rapid determination of cholesterol and dichlorvos was achieved,which had important academic value and application value.