Outline
The invention relates to a polymeric indicator fixed in a polymeric gel carrier, wherein the polymeric gel carrier comprises a hydrophilic polymer, wherein the polymeric indicator and the hydrophilic polymer are present together in the form of a combined cross-linked hydrogel network fixed by chemical bonds. The invention further relates to a method for preparing a polymeric indicator fixed in a polymeric gel carrier and to a sensor for measuring pH, which comprises the polymeric indicator fixed in a polymeric gel carrier.