Application to Gas Monitoring

Recently (1-3), we have described a series of in-struments for monitoring common pollutants, such as CO, NO, NO2, and H2S, in ambient air. The operat-ing principle of these analyzers was based on the electrochemical oxidation (electroreduction for NO2) of the gas at a catalyzed Teflon-bonded diffusion elec-trode (4), the potential of this sensing electrode being maintained constant at a value at which neither oxy-gen reduction nor electrolyte decomposition inter-fered with the measurement of the pollutant (essen-tially between 0.7 and 1.6V vs. RHE depending on the electrode catalyst). In general, the desirable features of such instru-mentation are signal stability, specificity (i.e., the abil ity to measure a pollutant in the presence o