Nitrogen oxide electrode

An additional path to protonation of coordinated NO is the reduction of the M-NO unit electrochemically (73). Such coupled reduction/proto-nation schemes have been argued to be relevant to enzymatic nitrogen oxide reductases (41). Farmer and coworkers (74) accomplished such reductions by using graphite electrodes modified by depositing... 

Choquette et al. investigated the possibilities of using a series of substituted sulfamides as possible electrolyte solvents (Table 12). These compounds are polar but viscous liquids at ambient temperature, with viscosities and dielectric constants ranging between 3 and 5 mPa s and 30 and 60, respectively, depending on the alkyl substituents on amide nitrogens. The ion conductivities that could be achieved from the neat solutions of Lilm in these sulfamides are similar to that for BEG, that is, in the vicinity of 10 S cm Like BEG, it should be suitable as a polar cosolvent used in a mixed solvent system, though the less-than-satisfactory anodic stability of the sulfamide family might become a drawback that prevents their application as electrolyte solvents, because usually the polar components in an electrolyte system are responsible for the stabilization of the cathode material surface. As measured on a GC electrode, the oxidative decomposition of these compounds occurs around 4.3—4.6 V when 100 fik cm was used as the cutoff criterion, far below that for cyclic carbonate-based solvents. 

The electroreduction of some typically inorganic compoimds such as nitrogen oxides is catalysed by the presence of polymeric osmium complexes such as [Os(bipy)2(PVP)2oCl]Cl, where bipy denotes 2,2 -bipyridyl and PVP poly(4-vinylpyridine). This polymer modifies the reduction kinetics of nitrite relative to the reaction at a bare carbon electrode, and provides calibration graphs of slope 0.197 nA with detection limits of 0.1 pg/mL and excellent short-term reproducibility (RSD = 2.15% for n = 20). The sensor performance was found to scarcely change after 3 weeks of use in a flow system into which 240 standards and 30 meat extracts were injected [195]. 

E. C. Szarvasky found that the electrolysis of hydroxylamine was accompanied by the spontaneous transformation of hydroxylamine into ammonia. Secondary reactions always occur—the base being reduced to ammonia at the cathode and at the anode oxidized to nitrogen oxides. F. Balia found that with various electrodes the percentage current yield of NaN02 NaN03 in the electrolytic oxidation of hydroxylamine with anodes of different metals was as follows ... 

Although the ISEs based on cobyrinates have good selectivity for nitrite over several anions, they also respond to salicylate and thiocyanate. To eliminate this interference, the nitrite-selective electrode based on ionophore 2 was placed behind a microporous gas-permeable membrane (GPM) in a nitrogen oxide gas-sensor mode (75). NOx was generated from nitrite in the sample at pH 1.7 and, after crossing the GPM, was trapped as nitrite by an internal solution that was buffered at pH 5.5 (0.100 M MES-NaOH, pH 5.5, containing 0.100 M NaCl). The internal solution was "sandwiched" between the nitrite-selective electrode and the GPM. 

Instruction Manual, Nitrogen Oxide Electrode, Model 95-46. Orion Research, Inc., Boston, MA, 1987. 

Amperometric gas sensors are - electrochemical cells that produce a - current signal directly related to the concentration of the - analyte by - Faraday s law and the laws of - mass transport. The schematic structure of an amperometric gas sensor is shown in Fig. 1. The earliest example of this kind of sensor is the - Clark sensor for oxygen. Since that time, many different geometries, membranes, and electrodes have been proposed for the quantification of a broad range of analytes, such as CO, nitrogen oxides, H2S, O2, hydrazine, and other vapors. 

Figure 9.4 shows a cross-sectional view of a laminated-type sensor for atmospheric nitrogen oxides based on YSZ, acting as an oxidation-catalyst electrode (Ono et al., 2004). The cell was fabricated by firing YSZ sheet on which the oxidation-catalyst platinum anode and the platinum counterelectrode were screen-printed. The porosity of the electrode is adjusted by adding resin powder into each electrode paste. 

Imanaka, N., Oda, A., Tamura, S. and Adachi, G.-Y. (2004) Total nitrogen oxides gas sensor based on solid electrolytes with refractory oxide-based auxiliary electrode. J. Electrochem. Soc., 151 (5), H113-16. 

Yao, S., Shimizu, Y., Miura, N. and Yamazoe, N. (1992) Use of sodium nitrate auxiliary electrode for solid electrolyte sensor to detect nitrogen oxides. Chem. Lett., 1587-90. 

Mukundan. R., Teranishi, K., Brosha, E.L, and Garzon, F.H. (2007) Nitrogen oxide sensors based on yttria-stabilized zirconia electrolyte and oxide electrodes. Electrochem. Solid-State Lett., 10 (2), J26-9. 

Gas-selective electrodes are used to a hmited extent in food analysis although, in certain areas of food production their use is quite common. The oxygen-selective electrode is often used on the production hnes for fruit and vegetable juices, where a vacuum has been apphed to remove air before packaging, this in order to check the residual oxygen content. S02-selective electrodes are used to determine the SO2 content of wines and other S02-treated liquids either directly or after the acid conversion of a component such as NaHSOa to SO2. Other electrodes are available for similar measurements, such as nitrogen oxide (for nitrite contents) and carbon dioxide (for either CO2 directly or CO2 from acid-converted carbonate or bicarbonate salts). There are perhaps other more accurate ways of determining such analytes, but the gas-selective electrode is... 

Lionetti, G., N. Carugno, and M. Neri Determination of nitrogen oxides in cigarette smoke with a gas-sensing electrode Proc. 6th Internat. Toh. Sci. Cong., Tokyo, Japan (1976) 177 CORESTA Inf. BuU., Spec. Edition 1976 Paper SO02, 92. 

Submerged arcs in liquid air produce nitrogen oxides, and, with nitrogen or oxygen dissolved in liquid argon, the technique has been used in attempts to prepare new oxides or nitrides of the electrode material. Similar attempts to produce argides of the electrode have failed, but perhaps the experiments should now be repeated since Kr, Xe, and Ra compounds have in the last year become w ell known [ ]. 

Iron-containing proteins are those in which iron atoms are bound with sulfur-containing ligands. The number of labile sulfur atoms is usually equal to that of iron atoms which varies between 1 and 18. The molecular mass of these proteins is in the range of 6000 to 750,000 units. Such proteins effect electron transfer in photosynthesis, nitrogen fixation, and respiration in mitochondria. They are capable of transferring electrons under a potential close to that of a reversible hydrogen electrode. Their oxidation-reduction potential is between +0.35 and -0.49 V. 

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