| 摘要 |
<p>An electrochemical detection cell (70) which includes a first membrane (21), an electrode carrier (22) having reference electrode (34) and counter electrode (35) thereon, a membrane support (25), an electrode carrier (27) having a sensing electrode (33) thereon, and a permselective membrane (28). Whatman filter papers (23,24,26) are positioned between the sensing electrode (33) and both the counter electrode (35) and reference electrode (34). The cell (70) allows air or gas ambient to address the membranes (21,28) and effects application of an electrolyte to the space between the electrodes by, for example, a wick (47) which extends between an electrolyte-containing reservoir (13) and the Whatman filter papers (23,24,26). A system for detecting a gaseous agent uses the aforementioned detecting cell (70) coupled with circuitry capable of applying a fixed D.C. voltage bias to the reference electrode (34) and superimposing a train of D.C. voltage-pulses on the fixed bias. Further circuitry (68, 98-111) is coupled to and responsive to signals from the sensing electrode (33). This circuitry (68, 98-111) determines the difference between the sensing electrode (33) signal at the end of each pulse minus that just before each pulse. The difference is proportional to the concentration of the test gas in the atmosphere adjacent to the sensor (33), and is a more specific and sensitive indication of the test gas concentration than prior art sensors.</p> |
