Determination Of Vitamin B By Electroactive PEDOT/nanocomposites

Electrochemical biosensor owing to its sensitivity, portability, specificity, rapidy,low cost, real-time in-vivo electrochemical detection and analysis, so, it has been animportant application value in biomedicine, environmental monitoring, food andpharmaceutical industry etc. Recently, the rapid growth inpoly(3,4-ethylenedioxythiophene)(PEDOT) nanocomposites have caused a greatinnovation in the construction of electrochemical biosensor and attracted extensiveattention. PEDOT has received a great deal of attention and has been widely studiedbecause it exhibits some very interesting properties including highly conductive, goodmechanical properties, superior biocompatability and more stable than most otherconducting polymers. However, PEDOT has low theoretical capacity and electrocatalyticactivity, these shortcomings limit the further application of PEDOT. While thedevelopment of PEDOT nanocomposites with excellent performance can fill the defect.Thus, the thesis is given of the research on electroactive PEDOT/nanocomposites used inthe construction of electrochemical biosensor.(1) Herein, functionalized PEDOT films were prepared by incorporation of twoelectroactive species, ferrocenecarboxylic acid (Fc-) and ferricyanide (Fe(CN)64-). Theelectrochemically synthesized electroactive species-doped PEDOT films have beencarefully characterized by Scanning electron microscopy (SEM), FTIR and UV-visspectra and various electrochemical techniques. Such nanostructured films combined theadvantages of PEDOT (high conductivity and stability) together with electroactivespecies (good electrochemical activity) and were applied as electrochemical sensors forsimultaneous determination of VB2, VB6and VC. The experiment results illustrated thatthe biosensors possessed high sensitivity and selectivity.(2) Six kinds of benzenesulfonate derivatives were used to dope PEDOT via a facileelectrochemical deposition strategy. Among them, the PEDOT/p-ABS film shows ahigher catalytic peak currents for VB2, VB9and VC, which might be ascribed to the largesurface area of nanostructured PEDOT/p-ABS-film, and the strong interaction between-NH-group doped in PEDOT/p-ABS film and VB2, VB9and VC via hydrogen bonding.Then PEDOT/p-ABS-/GCE was utilized for the simultaneous detection of these vitamins,and the linear ranges for VB2, VB9and VC are0.05~200μmol/L,0.5~1000μmol/L and1~1500μmol/L with limits of detection of0.015μmol/L,0.12μmol/L and0.46μmol/L,respectively.(3) Herein, a simple one-step electrodeposition method was developed for thesynthesis of poly(3,4-ethylenedioxythiophene)/Zirconia nanoparticles (PEDOT/ZrO2NPs)composite film. The obtained PEDOT/ZrO2NPs nanocomposite film showed largespecific area, high conductivity, rapid redox properties and had encapsulated structures, which make it an excellent sensing platform for sensitive determination of VB2, VB6andVC. Using differential pulse voltammetry, detection limits of0.012μmol/L,0.20μmol/L and0.45μmol/L were obtained for VB2, VB6and VC, respectively atPEDOT/ZrO2NPs/GCE. Furthermore, the modified electrode exhibited goodreproducibility. After20successive determinations of VB2, VB6and VC, the currentresponse signals at PEDOT/ZrO2NPs/GCE retained almost100%of its original value.(4) A highly sensitive and selective sensor based onpoly(3,4-ethylenedioxythiophene)(PEDOT) and β-cyclodextrin functionalizedsingle-walled carbon nanotubes (β-CD-SWCNT) composite was fabricated for thesimultaneous determination of folic acid (FA) and uric acid (UA) under coexistence ofascorbic acid (AA). The modified electrode combined the features of PEDOT andSWCNT, which hold excellent conductivity, low cost and high surface areas for workingas an efficient electron-mediator for FA and UA in the presence of AA. The differentialpulse voltammetry (DPV) data showed that the obtained anodic peak currents werelinearly proportional to concentration in the range of1~1000μmol/L with a detectionlimit of0.8μmol/L for FA and in the range of0.1~500μmol/L and with a detection limitof0.07μmol/L for UA. It also presented superior reproducibility and long-term stability,as well as high selectivity.