Impedance analysis of graphite + polyethylene and graphite + epoxy composite electrodes

Navarro-Laboulais, J.; Trijueque, J.; Garcı́a-Jareño, J.J.; Vicente, F.

doi:10.1016/0022-0728(95)04306-3

Cited by 24 publications

(8 citation statements)

References 16 publications

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“…The optimal graphite proportion for electroanalytical applications is related to the mass ratios and volume fraction for the type of carbon and epoxy used. It is associated with the conductivity and minimal double layer capacitance of the composite [14,15]. This ratio gives comparable conducting fraction to that found by Vicente et al [14].…”

Section: Electrode Preparationsupporting

confidence: 78%

Detection Mechanism of Metallized Carbon Epoxy Oxidase Enzyme Based Sensors

2003

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The coenzyme FAD has been identified to play an important role in the detection mechanism of oxidase enzyme based biosensors. Incorporating FAD into the carbon composite improved sensitivity to H 2 O 2 consequently increasing sensitivity to the respective analyte. The amount of active enzyme also increased thus enhancing the overall performance of the sensors. Polycarboxybetaine (PCB) has been used as a biocompatible membrane coating. The PCB coated sensors gave reproducible calibrations in protein solutions, which has been shown to be a valid protocol for testing biocompatibility. The importance of reporting selectivity in a manner which indicates the ™fitness of purpose∫ of biosensors has been discussed.

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Section: Electrode Preparationsupporting

confidence: 78%

Detection Mechanism of Metallized Carbon Epoxy Oxidase Enzyme Based Sensors

2003

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“…In all the analyzed composite samples the graphite content was greater than that required to overcome the first percolation threshold of the polymer + graphite binary system [21,[29][30][31]. The presence of metal powder in the matrix causes an increase in the system conductivity.…”

Section: Conductivity Of Composite Materialsmentioning

confidence: 97%

Electrochemical dissolution and passivation of nickel powder randomly dispersed in a graphite + polypropylene matrix

et al. 2006

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Nickel powder (10% in weight) randomly dispersed in a graphite (40%) + polypropylene (50%) matrix was studied as a composite electrode in a sulphuric-sulphate acid medium by means of voltammetry and Electrochemical Impedance Spectroscopy (EIS). Under voltammetric conditions, this thermoplastic material shows an electrochemical behaviour similar to nickel metal. However, under EIS measurement conditions the electrodissolution behaviour of the nickel powder is partially limited by the diffusion of the anions in the electrolyte in order to electroneutralize the excess of electrogenerated positive charge. The low frequency range of the measured impedance spectra can be interpreted as a parallel arrangement of a capacitive and a Warburg impedance, instead of a CPE element initially considered in the fitting. Values for CPE exponents lower than 0.85 are interpreted as a competition between a capacitive/transport contribution to the overall impedance response.

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“…the bulk resistivity or the volume fraction of the conductive phase) [2,3]. Graphite + polymer composites exhibit high solid bulk resistance [4][5][6] and very small relaxation times which, compared with the time scale of electrochemical experiments, allow us to disregard the details of the percolation phenomena through the solid and thus consider them as perfect resistors [1].…”

Section: Introductionmentioning

confidence: 99%