Simple and rapid synthesis of AIE-active GSH-protected copper nanoclusters for fluorometric detection of Cr3+

Fluorescent metal nanoclusters (FMNCs) have attracted significant attention in fluorescence sensor research due to their unique optical properties. Herein, glutathione-protected copper nanoclusters (GSH-CuNCs) were rapidly synthesized within 10 min by direct mixing of glutathione and copper nitrate solutions under weakly acidic conditions (pH 5–6). This as-prepared GSH-CuNCs exhibit a pronounced aggregation-induced emission (AIE) effect in ethanol solution. The generated fluorescence excited at ∼330 nm was found to be sensitive to the presence of chromium ions (Cr³⁺), which can be significant quenched by the addition of Cr³⁺. A fluorescent probe was designed for on-off detection of Cr³⁺ based on as-synthesized GSH-CuNCs. A linear relationship between fluorescence intensity and Cr³⁺ concentration was observed, with a detection limit of 600 nM. This probe is simple and rapid to fabricate, enabling fast and sensitive detection of Cr³⁺. It holds significant potential for practical applications in environmental analysis.