| 摘要 |
PROBLEM TO BE SOLVED: To measure a constituent that can be oxidized in an exhaust gas under the presence of a constituent that can be reduced with precision being required in terms of law, by forming the electrode of a limit electric pump for gas that can be reduced with a material that does not catalyze the reaction between the gas that can be reduced and a gas that can be oxidized. SOLUTION: An exhaust gas to be analyzed flows into a sensor 1 from an opening 8 and passes in front of electrodes 10 and 11 and is diffused. In this case, a gas that can be reduced should not react with a gas that can be oxidized. When the electrode 10 (cathode) is made of a material that does not show any catalysis such as platinum - gold, the reaction can be prevented. Then, the gas that can be reduced in the exhaust gas to be analyzed pumped out at a cathode limiting current in a limiting current cell 12, and the gas that can be oxidized is subjected to anode oxidation in a limiting current cell 13. The cathode limiting current is measured in a measurement resistor 18 from the electrode 10 and the anode limiting current is measured in a measurement resistor 19 from the electrode 11, and the total concentration of the gas that can be oxidized is determined from the strength of the anode limiting current. |
