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[reaction: see text] The development of an ion-selective chemosensor for Cd(2+) allows generation of a "real-time" sensor. Immobilization of the chemosensor on quartz was achieved in a simple monolayer and in a thin film using a polymer intermediary. As intended, the thin film contains much more chemosensor than the monolayer and provides measurable responses to aqueous Cd(2+) concentrations below 1 microM. Alkali and alkaline earth ions do not interfere with Cd(2+) sensing; Zn(2+) and Cu(2+) are potential interferents.

Title hydroxyquinoline derivatives (I) are used to probe the mechanism of non-radiative relaxation of the fluorophores in fluorescent chemosensors like (II). It is shown that both photo-induced proton transfer and photo-induced electron transfer processes can cause fluorescence quenching in these molecules. Proton shift from hydroxy to amino group in compounds (II) accompanied by complexation of metal cations inhibits the relaxation processes and, thus, allows for detection of metal cations by fluorescence. -(BRONSON, R. T.; MONTALTI, M.; PRODI, L.; ZACCHERONI, N.; LAMB, R. D.; DALLEY, N. K.; IZATT, R. M.; BRADSHAW, J.