Sensitive detection of glutathione through inhibiting quenching of copper nanoclusters fluorescence

[Display omitted] •Fluorescent copper nanoclusters (CuNCs) were synthesized through a facile one-pot process.•P-benzoquinone (PBQ) effectively quenched the fluorescence from the CuNCs.•Glutathione (GSH) reacted with PBQ rapidly and converted it into a non-quenching product.•The recovered fluorescence provided a sensitive “ON” signaling toward GSH down to 20 nM. A method for a sensitive fluorescence detection of glutathione was established. Glutathione-stabilized copper nanoclusters (CuNCs) were synthesized via a facile process. These CuNCs showed blue fluorescence with a peak around 450 nm. In the presence of p-benzoquinone (PBQ), the electron transfer from the copper nanoclusters to PBQ quenched the fluorescence of the CuNCs. Glutathione (GSH), as a reducing agent, formed a complex with PBQ. This formation inhibited the quenching from PBQ, and a restored fluorescence was obtained. This interaction provided a fluorescence enhancement for the measurement of GSH. Under the optimal condition, linear responses were obtained toward GSH in the ranges of 0.06–6.0 μM, with a limit of detection at 20 nM. This developed assay was easy in operation with high sensitivity and selectivity. The applicability was approved with successful glutathione measurements in real samples.