Electrolytic hygrometers are precision instruments for determining moisture content in gas samples, often referenced in EP monographs as part of the total allowable water vapor specification.
- Principle: Water vapor in the gas stream is absorbed and electrolyzed into hydrogen and oxygen. The current required is proportional to the moisture concentration.
- EP Use Case: Moisture determination in oxygen, carbon dioxide, nitrogen, and compressed air.
Advantages: Extremely sensitive (to <1 ppmv), stable over time, ideal for critical low-humidity applications.
