Preparation Of PEDOT Molecularly Imprinted Electrodes And Their Electrochemical Sensing Of Three Kinds Of Vitamins

Vitamins as trace nutrients in organisms have an important effect on adjusting the organism's metabolism.Its abnormal content will affect the normal physiological process and generate various diseases.Therefore,it is necessary to develop an efficient,fast,convenient and practical monitoring method.Molecularly imprinted electrochemical sensor is electrochemical sensing technology with the combination of molecularly imprinted technology,which not only has strong specificity recognition ability,high sensitivity and ability to resist terrible environment,but also has simple operation,fast,low cost,real-time monitoring and so on.Comparing with traditional electrochemical sensors,molecularly imprinted electrochemical sensors have been greatly improved in selectivity.As the current star of the family of the conductive polymer molecules,owing to its high conductivity,good environmental stability,biological compatibility and other advantages,poly?3,4-ethylenedioxythiophene??PEDOT?has been widely used in many fields such as thermoelectric materials,energy,batteries and electrochemical sensor,etc.In this thesis,the molecularly imprinted electrochemical sensor based on PEDOT has been successfully applied to the detection and analysis of three kinds of vitamins.?1?By ultrasonic and mixing process,a nanocomposite with good oxidation-reduction ability,high stability and strong catalytic ability,consisting of poly?3,4-ethylenedioxythiophene?:poly?strenesulfonate??PEDOT:PSS?,carboxymethyl cellulose?CMC?and reduced graphene oxide@palladium?rGO@Pd?was successfully prepared.A novel electrochemical sensor based on glassy carbon electrode modified with the prepared nanocomposite exhibited good sensing detection performance.Under optimal conditions,the prepared sensor displayed a good voltammetric response toward VK₃ in the concentration range from 0.4 to 90?M with a limit of detection of 0.014?M.Meanwhile,the prepared sensor has good reproducibility,stability and high sensitivity,and has been successfully applied to the VK₃ detection in serum and animal bloods.Besides,its selectivity toward VK₃ need to further improve.?2?The PEDOT-MIPs electrochemical sensor of VK₃ was prepared by electropolymerization of EDOT on the surface of glassy carbon electrode,wherein EDOT was served as the functional monomer and VK₃ as the template molecule.The developed sensor was characterized by scanning electron microscopy,cyclic voltammetry?CV?and linear sweep voltammetry?LSV?.The imprinted sensor could be applied to detect VK₃ with high sensitivity and selectivity.The linear response range was 0.009 to 35?M with a low limit of detection of 0.00031?M,and the developed imprinted sensor was successfully applied to the analysis of VK₃ in poultry medicine.?3?Molecularly imprinted PEDOT composite film was prepared by the electrochemical polymerization of functional monomer EDOT in the presence of template molecule VB₂ and two-dimensional tungsten sulfide?WS₂?nanosheet.SWCNTs nanohybrid electro-catalyst modified GCE as electrode substrate for supporting imprinted film was obtained by drop-coating SWCNTs dispersion containing graphene oxide?GO?.The imprinted sensor was characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy,and its performance and parameters was investigated and optimized using LSV.Under optimized conditions,the prepared imprinted sensor displayed a linear response to VB₂ in concentration ranges from 0.002 to 0.9?M with a detection limit of 0.7nM,and successfully applied to electrochemically detect VB₂ in drug samples.?4?A novel and simple strategy was proposed to prepare molecularly imprinted polymer?MIPs?nanocomposites consisting of both conducting polypyrrole?PPy?and a new two-dimensional layered graphene-like black phosphorene quantum dots?BPQDs?onto the surface of conducting poly?3,4-ethylenedioxythiophene?nanorods?PEDOTNRs?via the electrochemical polymerization.A novel molecularly imprinted electrochemical sensor based on PPy-BPQDs-MIPs/PEDOTNRs/GCE was successfully fabricated by the electrochemical polymerization of pyrrole in the presence of VC and BPQDs.The structure and morphology of the prepared MIPs electrode were characterized by transmission electron microscope,scanning electron microscopy,energy dispersive X-ray spectroscopy,and its parameters such as electropolymerization cycles,pH buffer solution,concentrations of template molecules and incubation time were optimized.The peak currents recorded by differential pulse voltammetry?DPV?demonstrated a linear proportional on VC concentrations ranging from 0.01 to 4 mM with a detection limit of 0.0033 mM.Moreover,the prepared imprinted electrode was successfully applied to detect VC in commercial drink soft samples.