An absolute galvanic detector for nitrogen dioxide

Abstract

The performance of a modified Hersch and Deuringer galvanic detector for nitrogen dioxide was examined. The results indicate that the response is coulometric at low flow-rates and low concentrations on the basis of 1 Faraday (96 487 C) per mole of nitrogen dioxide. This response is explained in terms of the electrochemical reduction of nitrogen dioxide to the nitrite ion or nitrous acid. The cell can thus differentiate between nitrogen dioxide and nitrous acid vapour, which might be present in humid air. The detector has an immediate application for calibrating low-concentration mixtures containing nitrogen dioxide, but further work is necessary to investigate the reliability of the selective scrubbers required for monitoring nitrogen dioxide in polluted, ambient air.