| abstract |
The invention relates to a sensor for determining a concentration of a substance contained in a fluid-containing matrix, with a measurement chamber ( 5 ), a sender ( 3 ) for the emission of optical radiation ( 6 ) into the measurement chamber, and a receiver ( 4 ) for receiving optical radiation which has traversed the measurement chamber, wherein the measurement chamber is designed for bringing into the matrix and is filled with a specific fluid, and the wall ( 12, 13 ) is at least sectionally permeable to the diffusion of the substance. A control and evaluation circuit ( 7 ) is connected to the sender ( 3 ) and controls the sender ( 3 ), and is connected to the receiver ( 4 ) for selecting the receiver signals and determines, from the receiver signal, a measurement for the concentration of the substance in the matrix. |