Membrane covered electrode

The response of the usual membrane-covered electrodes can be described by an empirical second-order lag equation. This consists of two first-order lag equations to represent the diffusion of oxygen through the liquid film on the surface of the electrode membrane and secondly the response of the membrane and electrolyte ... 

Biosensors fabricated on the Nafion and polyion-modified palladium strips are reported by C.-J. Yuan [193], They found that Nafion membrane is capable of eliminating the electrochemical interferences of oxidative species (ascorbic acid and uric acid) on the enzyme electrode. Furthermore, it can restricting the oxidized anionic interferent to adhere on its surface, thereby the fouling of the electrode was avoided. Notably, the stability of the proposed PVA-SbQ/GOD planar electrode is superior to the most commercially available membrane-covered electrodes which have a use life of about ten days only. Compared to the conventional three-dimensional electrodes the proposed planar electrode exhibits a similar... 

The best-known example of a membrane-covered electrode is the Clark electrode for determination of dissolved oxygen (Fig. 14.49,10). A membrane (usually PTFE) with pores of a size that lets only oxygen diffuse through is placed over a thin film of electrolyte on top of a platinum or gold electrode, the potential of this being controlled so as to reduce oxygen. The anode is usually a silver disc that acts simultaneously as reference electrode. It can be used for oxygen determination in gas or liquid phases. 

For the electrochemical determination of cell populations Matsunaga et al. (1980a) made use of the phenomenon that bacteria can be anodically oxidized. In a B. subtilis cell suspension the current difference between a bare electrode and a membrane-covered electrode was measured 0.210-9-2-KT8 cells could be detected with good reproducibility. In a similar manner, cell populations have been determined at electrodes modified with 4,4 -bipy-ridyl (Matsunaga and Namba, 1984a) or dyes (Nishikawa et al., 1982), and by cyclic voltammetry (Matsunaga and Namba, 1984b). 

Clean, sterilized, membrane-covered electrodes are inserted into the chamber. 

Other strategies employed were to use template synthesis, which has been widely used to prepare a variety of regulated nanostructured materials [212-215]. Commercially available polycarbonate and alumina membranes have plenty of well-organized nanopores of thickness equal to that of the membranes. Synthesis of polypyrrole on polycarbonate or alumina membrane-covered electrodes, followed by dissolution of the membranes resulted in polypyrrole nanotubules of a high surface density on the electrode substrates [216-218]. 

Nearly all sensors used for in situ registration of dissolved oxygen in seawater are of the amperometric membrane covered electrode type introduced by Clark et al. (1953). A de-... 

In order to quantify the enzyme adsorption at the carbon surface we determined the apparent activity using a second BQ or H2O2 indicating electrode. From the rate of product accumulation in the bulk phase we calculated for GOD a value of 100 pU/cm. This value is in the region of the apparent activities reported for membrane covered electrodes, i4 ... 

Kuroda, K., Silveira, R.G., Nishio, N., Sunahara, H., Nagai, S., 1991. Measurement of dissolved hydrogen in an anaerobic digestion process by a membrane-covered electrode. Journal of Fermentation and Bioengineering 71, 418—423. 

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