Graphite-Teflon electrodes

Phenols Amperometric tyrosinase biosensor based on a composite graphite-Teflon electrode modified with gold nanoparticles 3-20 nM 10... 

Fig. 1. The procedure of fabrication of composite Aumll-graphite-Teflon electrodes.

Tyrosinase Biosensor Based on a Composite Aucoll-Graphite-Teflon Electrode... 

A Tyr-Aucoll-graphite-Teflon electrode is constructed as described in Subheading 3.3. 

Carralero V, Mena ML, Gonzalez-Cortes A, Yanez-Sedeno P, Pingarron JM (2006) Development of a high analytical performance-tyrosinase biosensor based on a composite graphite-Teflon electrode modified with gold nanoparticles. Biosens Bioelectron 22 730-736... 

The membrane and electrode assembly used for the detection of oxides of nitrogen is similar to that used for CO detection, except that the sensing electrode is fabricated from a graphite Teflon mix. 

Serra et al. [60] l-Lactate Yoghurt Wine L-Lactate oxidase (LOx) and peroxidase (HRP)/physically entrapped in the composite electrode matrix together with the mediator Graphite-Teflon composite electrode/OV vs. Ag/AgCl Ferrocene... 

Guzman-Vazquez de Prada et al. [96] Methanol Ethanol Glucose Lactate (in the same assay) Wine Glucose oxidase (GOx), lactate oxidase (LOx), alcohol oxidase (AOx) and peroxidase (HRP)/ physically entrapped in the graphite-Teflon composite matrix Ferrocene-graphite-Teflon Ferrocene composite electrode/O V vs. Ag/AgCl... 

Serra et al. [105] Alkaline phosphatase Milk (process evaluation pasteurisation) Tyrosinase/physically included in the composite matrix Graphite-Teflon composite electrode/-0.10 V vs. Ag/ AgCl -... 

M.A. Del Cerro, G. Cayuela, A.J. Reviejo, J.M. Pingarron and J. Wang, Graphite-teflon-peroxidase composite electrodes. Application to the direct determination of glucose in musts and wines, Electroanalysis, 9(14) (1997) 1113-1119. 

B. Serra, A.J. Reviejo, C. Parrado and J.M. Pingarron, Graphite-Teflon composite bienzyme electrodes for the determination of L-lactate application to food samples, Biosens. Bioelectron., 14(5) (1999) 505-513. A.A.J. Torriero, E. Salinas, F. Battaglini and J. Raba, Milk lactate determination with a rotating bioreactor based on an electron transfer mediated by osmium complexes incorporating a continuous-flow/ stopped-flow system, Anal. Chim. Acta, 498(1-2) (2003) 155-163. 

G. Cayuela, N. Pena, A.J. Reviejo and J.M. Pingarron, Development of a bienzymic graphite-Teflon composite electrode for the determination of hypoxanthine in fish, Analyst, 123(2) (1998) 371-377. 

Fig. 65. A holder for graphite paste electrodes (a) A standard taper glass joint (6) A Teflon plug (c) A platinum or copper wire (d) The carbon paste.

Recently, Tachibana et al. [19] used a nickel mesh electrode containing a mixture of Teflon emulsion, graphite (or... 

The rotated disc electrode (RDE) is one of the most commonly employed hydro-dynamic electrodes. Figure 7.1 shows a schematic representation of a typical RDE. The electrode itself is a flat, circular disc of metal, graphite or an other conductor, and has a radius of r its area A, therefore, is straightforwardly nr. The disc is embedded centrally into one flat end of a cylinder of an insulatory material such as Teflon or epoxy resin. Behind the face of the electrode is an... 

Finally, it is possible to fill a small shallow hole the size of the electrode required with carbon paste. These pastes are made from particles of graphite and a suitable hydrophobic diluent such as Nujol [103], silicone rubber [104], paraffin [105], epoxy resin [106], Teflon [107], or Kel-F... 

Scheme 17.1. Schematic diagram of biosensor and wall-jet cell. (A) Screen-printed electrode front-view (1) silver ink acting as reference electrode, (2) graphite ink acting as working electrode successively modified with PB and (3) silver ink acting as counter electrode. (B) PB-modified screen-printed electrode side-view (1) polyester film as support for printing step, (2) graphite ink and (3) PB layer. (C) Wall-Jet flow cell side-view (1) inlet of the flow, (2) outlet, (3) cell made of Teflon and (4) glucose biosensor. (D) Wall-jet flow cell front-view (1) outlet, (2) inlet of the flow, (3) O-ring, (4) flow-cell and (5) glucose biosensor. Reprinted from Ref. [4] with permission from Elsevier.

A dispersion of graphite in ceresin wax has been suggested as a way to prepare an electrode suitable for use in nonaqueous solvents. The hot paste is tamped into a Teflon tube and allowed to solidify. No pretreatment is necessary, and the surface can be renewed by wiping with cellulose tissue. 

Electrodes made with carbon or graphite paste mixed with a hydro-phobic diluent such as Nujol, paraffin, silicone rubber, epoxy resin, Teflon, or Kel-F, have also been used. Comparative studies between the various types of carbon paste electrode have been carried out11. 

Many practical electrodes are prepared from powdered active mass and some conductive additive, such as carbonaceous materials, that are bonded to a metallic current collector with a polymeric binder such as PVDF (described in the previous section). Such electrodes can be measured directly. Is it very useful to measure such electrodes in their pristine from, before any electrochemical treatment, and then as a function of their electrochemical history. For quantitative analysis (phase composition, evaluation of concentration of constituents in mixtures, etc.) it is important to use internal standards in the sample. Fortunately, several components of composite electrodes, which are, in any event, contained in the sample measured, can be used as internal standards. These include the current collector (Cu, Al), the conductive additive, such as graphite, or the binder, such as Teflon. 

The catalysts and electrode materials used in PAFCs are also similar to those in acidic H2/air fuel cells. Carbon-supported Pt is used as the catalyst at both anode and cathode, porous carbon paper serves as the electrode substrate, and graphite carbon forms the bipolar plates. Since a liquid electrolyte is used, an efficient water removal system is extremely important. Otherwise, the liquid electrolyte is easily lost with the removed water. An electrolyte matrix is needed to support the liquid phosphoric acid. In general, a Teflon -bonded silicon carbide is used as the matrix. 

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