| Electrochemical sensor is one of important branch in analytical chemistry. Recently, the development of new sensing materials has become the mainstream development direction of electrochemical sensor. Poly(3,4-ethylenedioxythiophene): poly(styrene-sulfonate) (PEDOT:PSS) has become one of the star conductive polymer (ECPs) due to its excellent mechanical property, processibility, high transparency, good electrical conductivity, low intrinsically thermal conductivity, low price and commercial batch production. The aqueous dispersion of PEDOT:PSS is also more promising novel organic electrode materials. PEDOT:PSS not only can composite with different nanometer catalytic materials, biological materials and biological activity macromolecular according to design needs, but also make electron transfer quickly. Hence, PEDOT:PSS are promising candidates for the potential application of electrochemical sensor. However, there have only been a few reports on film electrodes obtained by deposition of water-dispersible PEDOT:PSS for application in electrochemical fields-due to PEDOT:PSS film easily swells, disintegrates, and peels off from the surface of the substrate electrode after immersion of the film electrode in aqueous solution. The development and application in the electrochemical sensor of high water stable PEDOT:PSS composite are currently hot and difficult. The thesis mainly focused on the preparation of high water stable PEDOT:PSS composites by adding of high soaking stable and adhesive materials or synthesis soaking stable and adhesive PEDOT derivate:PSS, and combined with carbon nanomaterials and clay materials. And the PEDOT:PSS composites were used for the electrochemical determination of biomolecule, pesticide, and synthetic dyestuff.(1) PEDOT:PSS-carboxymethyl cellulose (CMC) composites was obtained successfully by CMC with good biocompatibility mixed with an aqueous solution of PEDOT:PSS. PEDOT:PSS-CMC modified electrode had better water stability. Moreover, the electrochemical sensor based PEDOT:PSS-CMC composite was fabricated, and was used for the simultaneous determination of maleic hydrazide (MH), NaNO2, and salicylic acid (SA). PEDOT:PSS-CMC modified electrode showed high electrocatalytic activity, lower detection limit (0.11 μM,0.53 μM, and 0.83 μM), widest linear range (0.33-110 μM,1.6-116 μM, and 2.5-333 μM) and good reproducibility, stability and selectivity.(2) PEDOT:PSS-PVA-MWCNTs and PEDOT:PSS-PVA-GR-COOH composite modified electrodes was prepared successfully by mixed PVA and carbon nanomaterials (MWCNTs or GR-COOH) with an aqueous solution of PEDOT.PSS, and had better water stablility. Moreover, PEDOT:PSS-PVA-MWCNTs composite electrode was used for the electrochemical detection of epinephrine (Ep), uric acid (UA), and tryptophan (Trp), and showed high electrocatalytic activity, lower detection limit (0.15 μM,0.8 μM, and 0.015 μM), widest linear range (0.5-200 μM,3.0-300 μM, and 0.6-100 μM), and good reproducibility, stability, and selectivity. PEDOT:PSS-PVA-MWCNTs composite electrode was used for the electrochemical detection of niclosamide (NA), and showed high electrocatalytic activity, lower detection limit (0.05 μM), widest linear range (0.168-84 μM), and good reproducibility, stability, and selectivity.(3) Poly(EDOT-co-EDOT-AA):PSS was synthesized successfully. Poly(EDOT-co-EDOT-AA):PSS-GR and Poly(EDOT-co-EDOT-AA):PSS-HNTs-CMC were also successfully prepared by the incorporation of the graphene (GR), and halloysite nano powder (HNTs) and carboxymethyl cellulose (CMC) into a aqueous dispersion of Poly(EDOT-co-EDOT-AA):PSS. Poly(EDOT-co-EDOT-AA):PSS and it composite modified electrodes had better water stablility. Furthermore, Poly(EDOT-co-EDOT-AA):PSS modified electrode was used for the electrochemical detection of Ep and Trp (detection limit:0.3 μM,0.7 μM; widest linear range: 0.168-84 μM,1.0-112.0 μM); Poly(EDOT-co-EDOT-AA):PSS-GR composite modified electrodes was applied to detection MH (detection limit:0.3 μM; widest linear range:2.0-770 μM); Poly(EDOT-co-EDOT-AA):PSS-HNTs-CMC composite modified electrode was employed to detect vitamin B6 (VB6) (detection limit:2.0μM; widest linear range:16.7-250 μM). Simultaneously, Poly(EDOT-co-EDOT-AA):PSS and it composite modified electrodes also exhibited high electrocatalytic activity, good reproducibility, good stability and high selectivity.(4) Three composite were successfully prepared by PEDOT.PSS, PEDOTM:PSS, and Poly(EDOT-co-EDOT-AA):PSS composited with the mixed solution of single-walled carbon nanotube (SWCNTs) and PVA, respectively, their modified electrodes were used for the electrochemical detection of Ponceau 4R, respectively. Compared with other two electrodes, Poly(EDOT-co-EDOT-AA): PSS-PVA-SWCNTs modified electrode showed the best electrocatalytic activity, highest sensitivity, lowest detection limit (2.0 μM), widest linear range (16.7-250 μM), and best sensing stability, and was employed to determine Ponceau 4R of soft drinks. |
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