17] Determination of nitric oxide saturated solution by amperometry on modified microelectrode

Abstract

Publisher Summary This chapter describes the determination of nitric oxide saturated solution by amperometry on modified microelectrode. Nitric oxide (NO . ) is an endogenously synthesized free radical of great physiological and pathophysiological importance. Current techniques for the direct measurement of NO- include spectroscopic methods and electrochemical methods. However, all methods for the direct determination of nitric oxide require calibration. Saturated solutions of NO . in phosphate buffer prepared from NO . in a gas cylinder or from acid decomposition of nitrite have been used. Unfortunately, the concentration of the prepared solution is usually unknown. This chapter presents a fast and simple method for the determination of NO . concentration of the saturated (stock) solution. The method is based on a cylindrical microelectrode made from carbon fiber coated with porphyrin 11 for chronoamperometric (calibrationless) determination of NO . standard. The proposed method enables the determination of values of the diffusion coefficient of NO . The accuracy and precision are comparable with that given for concentration.