WS quantum dots-MnO nanosheet system for use in ratiometric fluorometric/scattered light detection of glutathione.

Based on WS quantum dots (QDs) as fluorescent signals and MnO nanosheets as second-order scattering (SOS) signals, a combination of fluorescence and scattered light was used to construct a ratio sensing platform for glutathione (GSH) detection. When MnO nanosheets are added to WS QDs, the fluorescence of WS QDs is quenched by MnO nanosheets through IFE. Large-sized MnO nanosheets increase the SOS of the system and gradually approach the fluorescence. After adding GSH to WS QDs-MnO, the MnO nanosheets were decomposed into Mn. The disappearance of the characteristic absorption peak of the MnO nanosheets suppressed the IFE to WS QDs, resulting in the fluorescence recovery of WS QDs. The reduction in size of MnO nanosheets after decomposition results in a decrease in the SOS of the system. Therefore, the ratio detection of GSH is obtained through the fluorescence and SOS dual signal response. Under optimal experimental conditions, the value of F/S is linearly related to the GSH concentration in the range 0 to 60 μM, and the limit of detection (LOD) of GSH is 0.12 μM. In addition, the system is also used for the determination of GSH in real water samples and human serum, with good analytical results. Graphical abstract Schematic principle of fluorescence/scattered light system based on WS QDs-MnO for GSH ratiometric detection.