WHAT ARE THE LIMITATIONS OF ELECTROCHEMICAL SULFUR DIOXIDE SENSORS?
There are two major drawbacks associated with standard electrochemical sensors. They exhibit a fairly rapid drop in sensitivity when exposed continuously to medium gas concentrations over a period of several hours to three days. They also exhibit very large cross sensitivity (typically up to 160%!!!) to nitrogen dioxide gas. The first problem is associated with the sensor’s internal structure. The second problem cannot be corrected by a selective filter. Filters that remove NO2 will also remove SO2. The new SEM(tm) sensor uses a novel electrode configuration that minimizes sensitivity loss and incorporates an additional scavenging electrode that minimizes NO2 interference.
