Determination of Copper Ion in Drinking Water Using Poly(vinyl alcohol)/3-Mercaptopropionic Acid-Capped InP/ZnS Quantum Dots Fluorescent Film

PVA/MPA-InP/ZnS QD fluorescent film for rapid detection of trace Cu²⁺ was developed using 3-mercaptopropionic acid (MPA)-capped InP/ZnS quantum dots (MPA-InP/ZnS QDs) as the fluorescence-sensitive material and polyvinyl alcohol (PVA) as the substrate. The microstructure, optical properties and mechanical properties of the fluorescent film were characterized. The results showed that PVA interacted with MPA-InP/ZnS QDs through hydrogen bonds. The fluorescence intensity of the film was significantly correlated with Cu²⁺ concentration in the range of 0–1000 nmol/L (R² = 0.95). The limit of detection (LOD) for Cu²⁺ was 23 nmol/L, and the response time was 6 minutes. Finally, the film was applied to the detection of trace Cu²⁺ in drinking water, beverages and alcoholic drinks with the advantages of high selectivity, rapid response and good portability, which exhibited a broad application prospect.