Method of determining the portion of an electrochemically convertible substance in a gas sample

摘要

A method for determining the portion of an electrochemically detectable substance in a gas sample includes the steps of introducing the gas sample into an electrochemical measuring cell 1 and generating a measurement curve i(t) by the electrochemical conversion of the substance in the measuring cell 1. The measuring curve i(t) increases from a reference line to a maximum value imax and drops back again to the reference line. Then, the maximum value imax and an area A below the measuring curve i(t) are determined. The area A is proportional to the portion of the substance in the gas sample. The method is improved in that a new measurement value is made available after a short time. This is achieved in that the maximum value in max and the area An of a previous measurement are compared to each other and a proportionality factor Kn is determined. The proportionality factor Kn is given by the ratio of the area An to the maximum value in max and, for a new measurement, a new maximum value in+1 max is determined and the portion of the substance in the gas sample is computed for the new measurement from the new maximum value in+1 max and the proportionality factor Kn of the previous measurement.