Table of Contents

Abstract: A review of using Griess Reaction method to determine nitric oxide production in biological systems.

Abstract: In this paper ITO thin films were deposited on alumina substrates by ultrasonic spray pyrolysis. The NO2 sensing properties of ITO thin films were investigated. The results show ITO thin films have good sensitivity to nitrogen dioxide.

Abstract: The electrochemical oxidation of nitric oxide (NO) gas at the Pt/Nafion^® electrode has been studied at a concentration of 500 ppm. The electrooxidation of NO taking place over a wide potential range can be described by a transcendental equation, from which the half-wave potential of the reaction can be determined. For NO oxidation with appreciable overpotentials but negligible mass-transfer effects, the Tafel kinetics applies. The obtained charge transfer coefficient (a) and the exchange current density (io) are 0.77 and 14 mA/cm², respectively. An amperometric NO gas sensor based on the Pt/Nafion^® electrode has been fabricated and tested over the NO concentration range from 0 to 500 ppm. The Pt/Nafion^® electrode was used as an anode at a fixed potential, preferably 1.15 V (vs. Ag/AgCl/sat. KCl), which assures current limitation by diffusion only. The sensitivity of the electrochemical sensor was found to be 1.86 mA/ppm/cm². The potential interference by other gases, such as nitrogen dioxide (NO₂) and carbon monoxide (CO), was also studied in the range 0-500 ppm. Both sensitivity for NO and selectivity of NO over NO₂/CO show significant enhancement upon using a cyclic voltammetric (CV) activation, or cleaning procedure.

Abstract: The electrochemical determination of nitric oxide in seawater with microelectrodes is reported in this paper. Two electrodes, ISO-NOPMC microsensor and modified platinum microelectrode, are evaluated for their performance in seawater. The peak current is found to be linear with the NO concentration in the range 1×10^-6-1.2×10^-5 mol/l for both microelectrodes. The detection limit of ISO-NOPMC microsensor is 1.4×10^-8 mol/l. Two methods for calibration of NO sensor, saturated NO solutions and decomposition of S-nitroso-acetyl-DL-penicillamine (SNAP), are discussed and compared. In addition, we examined the performance degradation of these microelectrodes in seawater due to complexation with seawater components.

Abstract: In this review we summarize our experience using a microelectrode to measure nitric oxide concentrations [NO] in living rat kidney tubules. In the anaesthetized living rat, the abdomen can be opened, and the kidney can be placed in a cup such that one can puncture a surface single tubular segment, 1-2 mm long, connected to one of 30,000 filtering glomeruli. The tubular segment can be viewed with a stereo microscope and punctured using sophisticated micromanipulators. The segment, ranging in diameter from about 15 - 35 um contains freely flowing RBC-free fluid, electrolytes, O₂, pCO₂ and NO gas concentrations, and a host of other known and unknown substances. After a “pre” puncture with a 7-10 um beveled glass pipette, intratubular [NO] can be directly determined by inserting, into the tubular lumen, the tip of a specially modified amperometric integrated electrode (WPI P/N ISO-NOP007). We review our in vivo experience with this electrode, emphasizing optimal practice to ensure appropriate calibration, stability, and selectivity for in vivo use. The electrode is highly selective for NO, and, despite fragility, with appropriate precautions, it can provide reproducible and highly sensitive NO measurements in the 40-1000 nM range.

Abstract: In recent years World Precision Instruments Inc. (WPI) produced for commercial use a selective and sensitive electrochemical sensor for the detection of the important biological free radical nitric oxide (NO). Though many kinds of NO sensors are now commercially available WPI offers a range of sensors of variable size and applicability for the detection of NO in vivo and in in vitro biomedical samples. This article overviews the working characteristics of the sensors and their utility for biomedical research.