A quinoliene-containing conjugated polymer-based sensing platform for amino acids

Three quinoliene-containing conjugated polymer (CP)-based sensing platform were prepared for amino acids. The three polymers containing bromine, imidazole, and hydroxyl structures are denoted as P1, P2, and P3, respectively. The fluorescence emission spectra of P2 in THF and in the presence of different concentrations of Cu²⁺ was found and P1 and P3 were also used to detect Cu²⁺. It is seen that both the intensity and the profile of the absorption of P2 in THF do not change very much along with increase of the quencher, Cu²⁺, concentration. Existence of an isoabsorption point in the spectra suggests two absorption species in the system, indicating formation of a Cu²⁺-P2 complex, which possesses an absorption centering at 455 nm. For Cu²⁺-P3, the cation could not be freed from the polymer in the presence of amino acid due to the reason described already.