Nitric oxide determination

Electrochemical Sensors for Nitrite and Nitric Oxide Determination 492... 

J. Katrlik and P. Zalesakova, Nitric oxide determination by amperometric carbon fiber microelectrode. Bioelectrochemistry 56, 73-76 (2002). 

Experimental method. In the flask P (see Fig. 1) a mixture was made up at an initial pressure of 200 mm and a temperature of 20° C. Then an electric heater was fitted on to the flask which was heated together with the explosive mixture in it. We estimated the temperature of the mixture by the change in pressure. After a steady temperature was reached (varying in different experiments between 200-300° C) the mixture was exploded. The heater was then removed and the nitric oxides determined as in 3. It was shown by special experiments that even after the flask had been in the heater for fifteen minutes there was no loss of nitric oxide after the explosion. In some experiments the mixture was cooled before the explosion, the flask P being wrapped in a cloth and abundantly wetted with liquid nitrogen. 

Shutenko Z, Henry Y, Pinard E, Seylaz J, Potier P, Berthet F. 1999. Influence of the antioxidant quercetin in vivo on the level of nitric oxide determined by electron paramagnetic resonance in rat brain during global ischemia and reperfusion. Biochem Pharmacol 57 199-208. 

Nitric oxide and NjO are direct intermediates in the denitrification pathway, the reduction of NO3 to Nj. Reduction to Nj is often incomplete, so that both NjO and Nj are equally important end products of denitrification, the ratio of NjO/Nj production being determined by soil physical properties. For example, NjO is the main end-product in acid soils, whereas low redox potentials and high organic matter content favour the further reduction to Nitric... 

Thus, nitric oxide seems to react in a complex manner. Simple addition to existing ions and initiation of new reactions, which might involve even carbon bond scission, seem to occur. At present our study of this system is incomplete. We have not been able to reconcile the complexity of the spectra with the findings of Meisels which are otherwise supported by our rate constant determinations. 

Mouse peritoneal macrophages that have been activated to produce nitric oxide by 7-interferon and lipopolysac-charide were shown to oxidize LDL less readily than unactivated macrophages. Inhibition of nitric oxide synthesis in the same model was shown to enhance LDL oxidation (Jessup etal., 1992 Yates a al., 1992). It has recently been demonstrated that nitric oxide is able to inhibit lipid peroxidation directly within LDL (Ho etal., 1993c). Nitric oxide probably reacts with the propagating peroxyl radicals thus terminating the chain of lipid peroxidation. The rate constant for the reaction between nitric oxide and peroxyl radicals has recently been determined to be 1-3 X10 M" s (Padmaja and Huie, 1993). This... 

Of crucial significance in deciding between various models have been estimates of the number of copper atoms required to transform the surface into a (2 x 3)N phase. This was the approach adopted by Takehiro et al 2 in their study of NO dissociation at Cu(110). They concluded that by determining the stoichiometry of the (2 x 3)N phase that there is good evidence for a pseudo-(100) model, where a Cu(ll0) row penetrates into the surface layer per three [ll0]Cu surface rows. It is the formation of the five-coordinated N atoms that drives the reconstruction. The authors are of the view that their observations are inconsistent with the added-row model. The structure of the (2 x 3)N phase produced by implantation of nitrogen atoms appears to be identical with that formed by the dissociative chemisorption of nitric oxide. 

Derive a rate expression that is consistent with this mechanism. Treacy and Daniels [J. Am. Chem. Soc., 11 (2033), 1955] have determined that the orders of the reaction with respect to oxygen and nitric oxide are one and two, respectively, at high pressures and less than one and greater than two at low pressures. Is the proposed mechanism consistent with this data ... 

Prasad A, Narayanan S, Waclawiw MA, Epstein N, Quyyumi AA. The insertion/deletion polymorphism of the angiotensin-converting enzyme gene determines coronary vascular tone and nitric oxide activity. J Am Coll Cardiol 2000 36 1579-1586. 

The first interest in the electroreduction of N02 or NO catalyzed by metal complexes is to model the activity of nitrite reductase enzymes.327 There is also an extensive growth in studies related to the development of metal complex-based electrochemical sensors for NO determination in biological and environmental samples 328 329 Nitrate disproportionates to nitric oxide and nitrate in aqueous solution. 

S. Trevin, F. Bedioui, and F. Devynck, Electrochemical and spectrophotometric study of the behavior of electropolymerized nickel prophyrin films in die determination of nitric oxide in solution. Talanta 43,... 

F. Bedioui, S. Trevin, and J. Devynck, Chemically modified microelectrodes designed for the electrochemical determination of nitric oxide in biological systems. Electroanalysis 8, 1085-1091 (1996). 

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