Abstract: The invention relates to an optochemical sensor consisting of a polymer matrix and a luminescent colorant material contained therein, whose emission power may be modified by the substances to be detected after being excited with electro-magnetic radiation. The polymer matrix is formed by at least one polymer, wherein no plasticizers have been added, which polymer contains phenyl groups in the main chain and may also be sterilized. the invention also relates to a method for producing the disclosed optochemical sensor, wherein a solution of a polymer is prepared, wherein 0.01 to 100 mMol luminescent colorant material per polymer is added to the solution and the mixture is solidified to obtain a homogenous membrane.