A sensor element for use in determining the concentrations of substances contained in gaseous and liquid samples includes a carrier layer and an indicator layer containing one or more indicator substances whose optical properties change depending on the concentration of the substances to be measured,...http://www.google.es/patents/US4755667?utm_source=gb-gplus-sharePatente US4755667 - Sensor element for determination of concentration of substances
Sensor element for determination of concentration of substances
