Electrochemical Gas Sensors for Mine Atmospheres: Portable Detectors for Carbon Monoxide and for Nitric Oxide/Nitrogen Dioxide Mixtures

摘要

A portable detector for mixtures of nitric oxide and nitrogen dioxide was developed using a porous silver cathode in sulfuric acid supporting electrolyte. Nitrogen dioxide was determined in the gas stream by electroreduction. The nitric oxide in the gas stream was oxidized to nitrogen dioxide by passing it over Cr(VI) on firebrick. Electroreduction gave the sum of NO + NO2. Analog circuitry was used to display the amounts of NO and NO2 separately. Two ranges available for each gas were, in parts per million, 0 to 10 and 0 to 50 for NO, and 0 to 2 and 0 to 10 for NO2.