Interfering Gases

No analytical method is completely specific. Gases present in the environment, other than the “target” gas of a measurement, may affect instrument response. Interferences are not necessarily linear, and may also exhibit time dependent characteristics.

Electrochemical sensors have problems with VOCs (Volatile Organic Compounds) so ensure to use Polarcept when dealing with VOCs. The VOCs can diffuse into the ethylene sensor and dissolve in its electrolyte.

Ripening fruit emit a complex mixture of hydrocarbons, including ethylene. Oxidation of these other gases in the electrochemical sensor cannot be readily distinguished from ethylene. This causes the ethylene value to be falsely high in the presence of interfering gas. Felix Instruments has tested a method to absorb some of the competing gases and provide better ethylene measurements. This method, PolarCept, uses distilled water in conditioning Chamber In and has been shown to filter out alcohols and produce less interference.