Copper nanoclusters coated with bovine serum albumin as a regenerable fluorescent probe for copper(II) ion

We show that copper nanoclusters coated with bovine serum albumin are viable probes for fluorometric determination of Cu(II) ion. The effect is attributed to the paramagnetic nature of Cu(II) bound to BSA. The ions Hg(II) and Fe(III) also give a strong effect but can be discerned by addition of EDTA. The probe can be regenerated by adding an excess of EDTA. The method is capable of detecting Cu(II) in the 0.02-34 mu M, and the limit of detection is 1nM. The method was applied to the determination of Cu(II) in spiked water samples. It is rapid, simple, and fairly sensitive. The method may also be applied to detect Hg(II) and Fe(III) if Cu(II) is absent.