Synthesis Of Modified Conducting PEDOT And Electrochemical Determination In Flavonoids

Poly(3,4-ethylenedioxythiophene) (PEDOT) is particularly interesting due to its excellent electrochemical activity, high conductivity, low bandgap, excellent environmental stability, and transparency in the doped state. And it has attracted great attraction in supercapacitor, thermoelectric material, solar cell and so on. However, some limitations still exist for PEDOT as sensing materials, such as the poor biological compatibility and low aqueous solubility. Therefore, solving the problems mentioned above is of great significance. Furthermore, electrochemical sensors have been extensively used in flavonoids compounds due to their low cost, fast, simple, sensitive, and real-time in-vivo electrochemical detection and analysis. Chinese herbal medicine is an important part of drugs. Among them, shikonin, rutin, luteolin, hyperoside and so on are the members of flavonoids family which have proved their efficacy as anti-cancer, anti-bacterial, and anti-viral properties and the determination of flavonoids are of great significance and received great attention. So far, some challenge still exists in the determination of flavonoids. In our work, we fabricated the sensors using PEDOT combine with metal ions-EDTA complex, carbon materials etc. or introduce functional hydrophilic group to EDOT side chain for the electrochemical determination of flavonoids. Specific content is as follows:(1) Nanostructured poly(3,4-ethylenedioxythiophene)/β-cyclodextrin (PEDOT /β-CD) particles was prepared by the oxidation of EDOT with FeCl3 using P-CD as template. The as-synthesized nanocomposites were characterized by scanning electronic microscopy (SEM), Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and electrochemical impedance spectroscopy (EIS). It was found PEDOT/β-CD particles were uniformly distributed, and hold an enhanced surface-to-volume ratio. The electrocatalytic performance of the nanostructured PEDOT/β-CD towards hyperoside and shikonin was investigated, which revealed that PEDOT/β-CD performed a better electrocatalytic activity than pure PEDOT. Thus, PEDOT/β-CD particles were proposed as electrochemical sensing platform to detect hyperoside and shikonin. This simple PEDOT/β-CD complex demonstrated very sensitive and selective hyperoside and shikonin detection capability, as well as high reproducibility and stability.(2) A novel redox polymer comprised of poly(3,4-ethylenedioxythiophene) (PEDOT) and ethylenediamine tetraacetic acid-Ni2+ (EDTA-Ni) complex serving as doping anions has been synthesised by a facile one-step electrochemical approach and utilized as an efficient electrode material for sensitive luteolin detection. The morphology, chemical structure and composition of the redox polymer were analyzed by SEM, UV-vis and FT-IR spectrum. Electrochemical tests revealed that the redox polymer was highly electrochemically reversible and exhibited good electrocatalytic activity to the redox reactions of luteolin with a linear range covering from 1 nM to 10 μM with a low detection limit of 0.3 nM of luteolin. This proposed electrochemical sensor can be applied in the determination of luteolin in capsule of Lamiophlomis rotata Kudo.(3) A simple and sensitive method is described for the electrochemical determination of shikonin, a widely used anti-tumoral agent, based on its electrochemical oxidation at a nanostructured poly(hydroxymethylated-3,4ethylene-dioxythiophene) (PEDOT-MeOH) electrode, which was fabricated by a facile electropolymerization method. Compared with bare and poly(3,4-ethylenedioxythio-phene) (PEDOT) electrodes, the PEDOT-MeOH film exhibited a distinctly higher activity for the electro-oxidation of shikonin. The PEDOT-MeOH electrode showed a wide linear response for shikonin in the concentration range of 1.0 nM to 10.0 μM with detection limit of 0.3 nM. Furthermore, the PEDOT-MeOH electrode displayed high stability, good reproducibility and high sensitivity for the detection of shikonin. This proposed electrochemical sensor can be applied in the determination of shikonin in urine samples.(4) We report the synthesis and application of a novel graphene oxide doped poly(hydroxymethylated-3,4-ethylenedioxythiophene) (PEDOT-MeOH/GO) compo-site film utilized as an efficient electrode material for simultaneous detection of rutin and ascorbic acid (AA). PEDOT-MeOH/GO film was synthesized on glassy carbon electrode (GCE) by a facile one-step electrochemical approach and was characterized by scanning electron microscopy, UV-vis spectroscopy, FTIR spectra and electrochemical methods. Then the PEDOT-MeOH/GO/GCE was applied successfully in the simultaneous detection of rutin and AA. The results showed that the oxidation peak currents of rutin and AA obtained at the PEDOT-MeOH/GO/GCE were much higher than those at the traditional conducting polymer PEDOT/GO/GCE, PEDOT-MeOH/GCE, PEDOT/GCE, and bare GCE. Under optimized condition, the PEDOT-MeOH/GO/GCE exhibits high sensitivity towards rutin and AA with the detection limits are 6 nM and 2 μM, respectively, which are lower than previously reported electrochemical sensors.