Platinum-fibre electrodes

A platinum-fibre electrode for detection of Cu(ll) and Cud) in non-aqueous solution... 

Some electrochemically active substances that can generate photons on an electrode surface are suitable labels for homogeneous immunoassays. A labelled antigen exhibits an electrochemical reactivity and produces luminescence, but when it is immunochemically complexed, the labelled antigen loses its electrochemiluminescent properties. One optical immunosensor for homogeneous immunoassays was assembled by spattering platinum on the end surface of an optical fibre. Spattered platinum maintains optical transparency and functions as an electrode. An optical electrode efficiently... 

A system underpinned by commercially made screen-printed electrochemical cells was described by Palmisano et al. [19]. The cells were converted into biosensors for lactate in milk and yoghurt by addition of an electrochemically polymerised barrier to interference and a layer composed of lactate oxidase, glutaraldehyde and BSA. These steps appeared to have been carried out by hand. As there was no outer diffusion-limiting membrane, the linear range of the sensors was quite small (0-0.7 mM). They were incorporated into a FIA with a microdialysis unit based on a planar membrane and a buffer reservoir (earlier work used a microdialysis fibre with a platinum electrode [29]. The concentration of lactate was determined in various milks (0.27-1.64 mM), and in raw milk (c. 0.5-0.9 mM) left to degrade on the laboratory bench. The recovery of the microdialysis unit, 2.6%, implied that the sensor had an ability to return measurable currents for very low concentrations of lactate. A further implication is that the electro-polymerised layer was very effective at preventing interference. 

We developed a submersible electrode assembly, connected to a 50 ft (24 m) long shielded cable (via environmentally-sealed rubber connectors), for the real-time in-situ monitoring of the TNT explosive in natural water [10]. Such sensor assembly consists of the carbon-fibre, silver, and platinum working, reference, and counter electrodes, respectively, and operates in the rapid square-wave voltammetric mode. Such a remote/submersible probe circumvents the need for solution pumping and offer greater simplification and miniaturization. The facile reduction of the nitro moiety allowed convenient and rapid square-wave voltammetric measurements of ppm levels of TNT. Lower (ppb) concentrations have been detected using a... 

Sloan and Talbot [113] reported a study of the anodic exposure of autoclave-cured 30-ply unidirectional AS-4/3501-5a carbon epoxy laminates in unaerated 0.5 M pH 7 sodium chloride at ambient temperature, against a platinum counter electrode. Crack formation was observed at potentials above 600 mV (SCE) at currents as low as 1 pAcm. Discoloration (yellowish brown) of the electrolyte was observed at potentials above 900 mV with both the carbon/Pt and Pt/Pt electrode systems. The reinforcement fibres... 

A report from Kyushu University in Japan [2], revealed that researchers there have developed a nanometre-sized, carbon fibre-based, electrode catalyst for polymer electrode fuel cells (PEFC). This catalyst uses half the platinum used in existing PEFC catalysts with consequent cost savings. Fuel cells with the new catalyst generate power at least equal to that of current PEFC. Previously it was thought that it was difficult to have nanometre-sized carbon fibre hold platinum uniformly at high density. The breakthrough achieved by the researchers was to treat the fibre surface and thereby satisfactorily prevent the platinum from coagulating. 

The selection of materials and fabrication techniques is crucial for an adequate sensor function and the performance of a sensor often ultimately depends upon these factors. Consequently, future developments in sensor design will inevitably focus upon the technology of new materials. Materials used in electrochemical sensors are classified as (1) materials for the electrode and supporting substrate (metals platinum, gold, silver, and stainless steel carbon-based materials graphite, carbon black, and carbon fibre new mixed materials or organic electroconductive... 

It should be noted that regeneration of acetic acid fi om sodium acetate is of certain practical interest, since sodium acetate is formed as a by-product in the manufacture of synthetic fibres. A 10% solution of sodium acetate is placed into the central compartments of the electrodialyzers. The anode compartment is filled with 0.1 N sulfuric acid solution and the cathode compartment with 0.1 N caustic soda solution. The electrodes are made of platinum, and the current density is 6.5 A/dm. ... 

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