Luminescent optical sensors.

Abstract

Luminescent optical sensor. An optical device is described capable of determining, in a manner which is continuous, reversible and in real time, the concentration of low molecular weight alcohols and water vapour contained in a liquid, semi-liquid or gaseous sample. Said device utilises certain luminescent aryl- substituted heterocyclic organic compounds (e.g. 5-(4- aminophenyl)-2-(2-pyrazinyl)thiazole) whose visible radiation emission intensity, wavelength and duration are modified in the presence of increasing concentrations of said analytes (e.g. methanol, ethanol, n-propanol, 2- propanol and water) contained in the sample. There is also described the adaptation of said optical sensor to the monitoring of such analytes in gasoline, naphtha or other fuels by means of the use of a fibreoptic system combined with the immobilisation of the luminescent compound in an appropriate polymeric matrix. In addition, the optical device can be used for monitoring said analytes in any other sample provided that the nature or majority component of the same is non-protic in character. The sensitivity to the various low molecular weight alcohols and water is a function of the structure of the luminescent compound used, of the immobilisation procedure of the same and/or of the majority component in the sample.