Synthesis of CuInS2 quantum dots for synchronous fluorescent assay of glutathione in foods and biological fluids

Synchronous fluorescence spectra equipped with the unique scanning mode have aroused tremendous interest in recent decades. It is not only able to improve the selectivity and spectral resolution, but also decrease the interference on account of light scattering via technique simplify of the emission spectra. Based on this principle, synchronous fluorescence was successfully applied to detect glutathione (GSH) based on CuInS2 quantum dots (CuInS2 QDs). The procedure carried out through the mechanism of electron transfer. Due to admirable design, this assay provided a brilliant linear range (0.1–100 μM) and an excellent detection limit of 73 nM without any complex modification on CuInS2 QDs. For further application, the near-infrared emission CuInS2 synchronous fluorescent probe was used to detect the content of GSH in cherry tomatoes and urine, which the quantitative spiked recoveries were 101%–104% and 99%–105%, respectively. Additionally, the residual rate of GSH in cherry tomatoes along with time variation under different temperature conditions was also monitored, which would presage more opportunities for the application in foods and biological fluids.