Electrooxidation of peroxynitrite in simulated body fluid at platinum electrode.
Peroxynitrite, a potent albeit deleterious biological oxidant, was electrooxidized at a bare platinum electrode in a medium of simulated body fluid (SBF) to nitrite anion and molecular oxygen. The SBF, prepared in accordance with literature procedure, has a pH of 7.4 and an ionic strength of 0.16. In this medium, peroxynitrite was observed to undergo a diffusion-controlled (D=1.63 x 10(-5) cm2/s) oxidation process at a bare platinum electrode with a heterogeneous rate constant, k(s), of 0.029 cm/sec. The formal redox potential, Eo', of this biological oxidant was determined as 1.18 V with respect to saturated calomel electrode (SCE) in a 2e- oxidation process. The electrochemical response of the oxidation process, measured in unit of current, is observed to be concentration dependent with a limit of detection of 1.6 x 10(-7) M. The linear dynamic range of the observed current-concentration plot extends over the entire concentration range studied. These observations make this electrochemical method a feasible technique for quantitative determination of peroxynitrite in vivo and in vitro.
Iwunze
M O
MO
Department of Chemistry, Morgan State University, Baltimore, MD 21251, USA. miwunze@jewel.morgan.edu
D001826:Body Fluids / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D004572:Electrolysis; D006863:Hydrogen-Ion Concentration; D016877:Oxidants / Q000032:analysis* / Q000737:chemistry; D010084:Oxidation-Reduction; D030421:Peroxynitrous Acid / Q000032:analysis* / Q000737:chemistry; D010984:Platinum / Q000737:chemistry*
D016877:Oxidants; D030421:Peroxynitrous Acid; D010984:Platinum