Bimetallic nanoclusters with strong red fluorescence for sensitive detection of hypochlorite in tap water

Gold-silver nanoclusters (Au-AgNCs) were synthesized by simultaneous chemical reduction of Au(III) and Ag(I) ions in one pot, using bovine serum albumin as both a template and a reductant. The Au-AgNCs have an average size of 2.4 nm and display strong red fluorescence (with an emission peak at 610 nm on excitation at 360 nm). The fluorescence quantum yield can reach 18.6%. Fluorescence is strongly quenched by hypochlorite, while other common anions have minor (or no) effects on fluorescence. Based on these findings, a fluorometric method was developed for the determination of hypochlorite. The method has a linear response in the 0.7 to 15 μM concentration range, with a limit of detection as low as 80 nM. It was successfully applied to the determination of hypochlorite in (spiked) tap water. Gold-silver nanoclusters with strong red fluorescence were synthesized by simultaneous chemical reduction of Au(III) and Ag(I) ions in one pot, and a sensitive and selective method for the detection of hypochlorite was developed based on the quenching of the fluorescence of the nanoclusters.