Abstract
As a carcinogen, hexavalent chromium (Cr(VI)) has attracted much attention for its quantitative detection. Herein, fluorescent S,N-codoped Cu/Ce-DAMP nanoparticles (S,N-codoped Cu/Ce NPs) were obtained by doping Ce2(SO4)3 in DAMP (4,6-diamino-2-mercaptopyrimidine)-encapsulated Cu nanoclusters (Cu NCs) via a simple, rapid, hypothermic, green and energy-saving self-assembly synthesis method that can detect Cr(VI). The obtained Cu/Ce NPs exhibited double emission peaks at 470 nm and 610 nm. Based on the aggregation-induced emission (AIE) effect, the fluorescence emission at 610 nm is significant, and the quantum yield is as high as 20.19%. The fluorescence emission at 610 nm can be selectively quenched by Cr(VI) due to the internal filter effect (IFE) and dynamic quenching, while the weak fluorescence at 470 nm remains almost stable. Based on this, a fluorescence assay method for Cr(VI) was established, with good linearity in the concentration range of 0.5–120 µM and a detection limit (LOD) of 134 nM. Using a smartphone to take photos of the fluorescence signals of Cr(VI) solutions can achieve rapid visual detection, with a linear range of 10–130 µM and an LOD of 2.35 µM. The proposed method was successfully applied to the detection of Cr(VI) in actual water samples.