ECN publication
Haalbaarheidsonderzoek: ontwikkeling van een ethanolsensor t.b.v. opslag van fruit
Published by: Publication date:
ECN 1-3-1999
ECN report number: Document type:
ECN-C--99-020 ECN publication
Number of pages: Full text:
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The feasibility of low concentration (50 to 500 ppb) ethanol measurementswas investigated for use as control parameter in a patented 'Dynamic Control System' (DCS) for cooled fruit and vegetable storing areas. The measurements were carried out in two ways, directly in the gas phase, and at concentrations to be found in the condensation water (circa 1 mM) of the storage cells. Measurements in the liquid phase using a field effect transistor (FET) in a pH-sensor-actuator, described elsewhere, have proved that the possibilities of this method for ethanol determination are rather limited. The pH sensor part of the device provides no suitable signal, whereas the 'actuator' part of the device provides only an indirect electrochemical signal. Owing to the indirect fashion of the signal, pursuing this detection scheme would demand more research. This device could not directly be tested with gas samples, presently it can only be used with aqueous ethanol solutions. Solid Polymer Fuel Cell (SPFC) sensing devices have been used to demonstrate the feasibility of ethanol measurements in aqueous solutions and in gas phase. A home-made fuel cell was used for measurements in aqueous solutions, whereas for gas-phase measurements a modified version of a commercial breath testing apparatus (Lion Laboratories) was used. The blanks and calibration lines indicated the suitability of the modified breath test apparatus for low concentration gas-phase ethanol determination. The effect of differences in the water vapor concentrations, and the interference of other organic compounds present in cooled fruit and vegetable storing areas have also been investigated

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