| 摘要 |
A method of determining ammonia in a gaseous or liquid sample is disclosed. A sensor comprising a sensing electrode, a reference electrode, a semi-permeable membrane and an electrolyte is used. The electrolyte is buffered to a pH value between 4.5 and 6.5 and is initially free of any salt capable of dissociating to form therein ammonium ion. The electrolyte may optionally contain at least 25% v/v of a water miscible solvent having a dielectric constant of at least 10. In the latter case the pH of the electrolyte is between 5.5 and 7.5. The potential between the sensing electrode and reference electrode is monitored as a measure of ammonia in the sample.
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