Amperometric measurement of gaseous hydrogen sulfide via a Clark-type approach

The direct oxidation of hydrogen sulfide in the range 2.0–20 parts per million by volume (ppmv) using a Clark-type amperometric gas sensing methodology is investigated via amperometric transients at 298 K. The diluent gas employed is air (20.9% O2 in N2), and it is shown that the observed current transients are limited by transport through the membrane covering, reaching a steady-state value within at least 200 s for one of the manifestations described. The measurement system presented is shown to be operational over a long time (tens of hours), provided certain quantification protocols are employed; the latter are suggested as pragmatic guidelines for the deployment of this detection methodology. Importantly and notably, it is shown that readily-oxidizable gases such as carbon monoxide and molecular hydrogen are observed not to interfere with the measurement quantification.