Plasticizer-free optode membranes for dissolved amines based on copolymersfrom alkyl methacrylates and the fluoro reactand ETHT 4014

A new class of fluorogenic copolymers has been synthesized that reversibly interacts with dissolved aliphatic amines resulting in a change in fluoresc ence, The copolymers are composed of different methacrylate monomeric units , such as hexyl methacrylate and the dye monomer 4-[N,N-bis(11-methacroyloy loxyundecyl)amino]-4'-trifluoro-acetylstilbene (ETHT 4014). Upon exposure t o aqueous amine solutions, thin layers of the copolymers show a decrease in fluorescence at a wavelength around 520 nm and an increase in fluorescence at around 420 nn, The change in fluorescence- is based on the nucleophilic addition of amines to the trifluoroacetyl group of the reactand, thus caus ing a change in the degree of electron delocalization, Since the sensor lay ers are composed of copolymerized components, they exhibit superior optiona l stability to sensors based on plasticized PVC, and their lack of plastici zers enhances the shelf lifetime.