F-900 Instruction Manual rev. 1/16/2014
1554 NE 3
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Ave, Camas, WA 98607, USA Phone (360) 833-8835 Fax (360) 833-1914
[email protected] http://www.felixinstruments.com
58
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.
The table below details the approximate concentration in parts per million of interfering gas
required to cause a 1 ppm detection in the ethylene analyzer. Please note that the response values
given are not absolute.
Table 1: Interfering Gas and the F-900 sensor
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 is
currently experimenting to see the extent of the interference, as well as testing a method to absorb
some of the competing gases and provide better ethylene measurements. Using Conditioning
Chamber B with distilled water has been shown to filter out alcohols and produce less interference
(page 32). Please monitor the F-900 support forum for progress updates.
