Saline platinum oxidation

In saline, platinum oxidation starts at a standard potential >0.2 V. The oxidation reaction can be reversed by negatively biasing the electrode (Fig. 2) (Table 1). At a given voltage, E, the ratio of oxidized [O] to reduced [R] species can be described by Nernst equation ... 

Cyclic voltammetric studies were conducted on a platinum electrode in normal saline solution containing different concentrations of prothrombin or thrombin. With addition of small amounts of prothrombin to 0.154 M NaCl, the hydrogen peaks are suppressed, the currents in the platinum oxide... 

This chapter commences with a review of a limited number of ternary hydride systems that have two common features. First, at least one of the two metal constituents is an alkali or alkaline earth element which independently forms a binary hydride with a metal hydrogen bond that is characterized as saline or ionic. The second metal, for the most part, is near the end of the d-electron series and with the exception of palladium, is not known to form binary hydrides that are stable at room temperature. This review stems from our own more specific interest in preparing and characterizing ternary hydrides where one of the metals is europium or ytterbium and the other is a rarer platinum metal. The similarity between the crystal chemistry of these di-valent rare earths and Ca2+ and Sr2+ is well known so that in our systems, europium and ytterbium in their di-valent oxidation states are viewed as pseudoalkaline earth elements. 

Butler [3] determined inorganic arsenic species in non saline waters by ion exclusion chromatography with electrochemical detection. Two species were separated by ion exclusion chromatography using 0.10M orthophosphoric acid eluent. Arsenic(III) was detected by its oxidation at a platinum wire electrode. Measurement of total inorganic arsenic after reduction of arsenic(V) to arsenic(III) by sulphur dioxide enabled... 

It is usually assumed that the metal is deposited on an electrode that must be replaced during the process, and that the anode is insoluble. The anodic reaction is oxidation of water to oxygen and/or oxidation of anions, e.g. CN. For aqueous solutions with a low salinity, titanium anodes coated with TiO and IrO or with platinum are mostly used. 

Porphyrinic catheter-protected sensors can be sterilized with ethylene oxide and used for NO measurement in humans. For measurements of NO in veins or arteries, an intervenous catheter is used. TVo cannulae are inserted into a vein. A 24 G catheter is inserted retrogradely and a 23 G butterfly needle is positioned anterogradely with its tip 10—15 nun from the end of the catheter. The catheter is flushed with 0.5 ml heparin (5000 U/ml) and a nitric oxide sensor is mounted on a 24-G needle and is placed so its tip protruded 1-2 mm beyond the end of the catheter. A platinum-wire counter electrode and silver/silverchloride reference electrode can be placed on the skin adjacent to the vein and covered with conductive gel. Heparin solution physiological saline or drugs can be infused continuously throu the butterfly needle. Infusion of acetylcholine causes a dose-dependent NO signal, attenuated by co-infusion of inhibitor of nitric oxide synthase L-NMMA or L-arginine (Figure 19). 

This chapter is devoted to a review of material issues for HT-PEMFC components and is built on relevant evaluation of data from literature on membrane oxidation, acid loss, platinum dissolution, and carbon corrosion. Finally, the state-of-the-art durability of PBI-based fuel cells is summarized. For certain applications, like in mobile auxiliary power units exposed to severe vibrations and road dust or to maritime saline mists, the picture becomes more complicated and knowledge today is rather limited. 

Fig. 3 (a) SEM image of a 3 x 3 array of platinum nanopores, (b) Cyclic voltammetry at different size arrays for the single electron oxidation of 1 mM ferrocenemonocarboxylic acid in 0.01 M phosphate buffered saline solution at pH 7.4 (scan rate 5 mV s , nanopore radius 225 nm). Reproduced from ref 36 with permission from the American Chemical Society. 

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