PolarCept

PolarCept is the use of distilled water in conditioning Chamber In to filter out or trap some of the interfering gases. Gas from the sample environment is passed through the water trap. Some of the polar molecules are held in the trap, while ethylene passes through the water trap to the sensor, where oxidation occurs. CO₂ is released as the oxidation product from the sensor. The water being used can become saturated after several minutes, so it must be cleaned of the trapped interfering gas molecules. Trapped interfering gases are driven out of the water during the cleaning time by a concentration gradient.

It is recommended to always use the PolarCept filter when measuring a gas mixture or interfering gases present will be reported by the instrument.

Alcohols can induce a baseline shift and/or change the sensitivity of the ethylene sensor. To recover the sensor after exposing it to alcohols, run it with clean air for a few days.

PolarCept: Measure

PolarCept: Clean

Figure 8: Top: diagram of measure period during use of PolarCept. Bottom: diagram of cleaning period of PolarCept.