Monodisperse BSA-conjugated zinc oxide nanoparticles based fluorescence sensors for Cu2+ ions

Bovine serum albumin conjugated zinc oxide nanoparticles (BSA-ZnO) were used as selective copper ions probes by fluorescence spectroscopic technique. The results showed that the fluorescence of the BSA-ZnO nanoparticles could be quenched only by Cu2+ in physiological buffer solution. The optimum fluorescence intensity was found to be at pH 7.0 with a temperature of 25 °C. Under these optimum conditions, the detection limit of Cu2+ ions was 6.09 × 10−7 mol L−1. The effect of foreign ions on the fluorescence intensity of BSA-ZnO nanoparticles was also studied and foreign ions showed low interference response in detecting of Cu2+ ions. Moreover, the quenching was discussed to be a static quenching procedure, which was proved by quenching rate constant Kq (6.98 × 1012 L mol−1 s−1).