Determination of zinc in aqueous solution using CdSe/ZnS quantum dots functionalised with [carboxymethyl-(4-mercapto-phenyl)-amino]-acetate

CdSe/ZnS quantum dots functionalised with [Carboxymethyl-(4-mercapto-phenyl)-amino]-acetate displayed selectivity for Zn2+ ion when tested against a range of other commonly available metal ions in buffered aqueous solution (pH 7.0 ± 0.1). The probe displayed an enhancement in its fluorescence intensity upon addition of Zn2+ attributed to a cancellation of a photoinduced electron transfer process from the bound receptor to the excited quantum dot that otherwise led to non-radiative decay. Good linearity was established for Zn2+ in the 0.2 to 5.0 mM range.