Spectral dependences of optical absorption of Rhodamine B immobilized in a film on the concentration of copper ions in water

The influence of copper ion concentration on the absorption spectrum of Rhodamine B in molecular form in an alcohol solution and immobilized in a polymer hydrogel film was studied. The sensitivity of the system to the presence of copper ions at a concentration of 0.1 mg/l, sufficient for practical use, is shown. The insolubility of Rhodamine B in water when it is immobilized in the volume of a photopolymerizing hydrogel film makes it possible to create a chemosensor that is stable at long exposures and can sense ultra-small concentrations of the analyzed impurity.