Selective and sensitive detection of copper(II) based on fluorescent zinc-doped AgInS2 quantum dots

Sensitive and selective strategies for the rapid detection of hazardous heavy metal ions in aqueous solution are of great significance. In this study, hydrophobic zinc-doped AgInS2 (AIZS) quantum dots (QDs) are synthesized by hot-injection method, and then transferred into water-dispersible by sodium dodecyl sulfate (SDS) via miniemulsion/solvent evaporation technique. The as-prepared hydrophilic AIZS QDs are successfully applied for the detection of divalent copper ions in water. The photoluminescence (PL) of the hydrophilic AIZS QDs is quenched by Cu2+ ions, which could be contributed to effective electron transfer from QDs to Cu2+, as verified by corresponding X-ray photoelectron spectroscopy (XPS). The probe possesses low relative standard deviation of 2.1% and wide linear range from 0 to 340 mu M with a limit of detection (LOD) as low as 27.3 nM. What's more, the sensing system is not interfered by other cations, indicating its good selectivity toward Cu2+. The QDs-based fluorescent sensor possesses greatly practical potential to determine the concentration of copper(II) in drinking water and natural water resources.