High sensitivity detection of CN– based on oxidase properties of Cu/Ag nanoparticles without additional oxidant

Due to the highly toxic nature of cyanide ions (CN–) and wide distribution in the environment, the establishment of rapid and sensitive detection methods of CN– is of great concern. In this work, we have synthesized Cu/Ag nanoparticles (Cu/Ag NPs) with oxidase activity, and established a luminol-fluorescein sodium-Cu/Ag NPs chemiluminescence resonance energy transfer (CRET) system, which can achieve high sensitivity determination of CN–. Based on the strong coordination effect between CN– and Cu2+, CN– interacts with Cu2 + in Cu/Ag NPs, which significantly decreases the oxidase activity of Cu/Ag NPs, and quenches the chemiluminescence (CL) signal of luminol-fluorescein sodium-Cu/Ag NPs CRET system. In this system, the concentration of CN– is linearly related to the CL signals of the luminol-fluorescein sodium-Cu/Ag NPs system, and the linear range is 0.05–4.00 μM, with a low limit of detection (LOD = 0.026 μM). Furthermore, the system has been successfully employed for the detection of CN– in tap and lake water, with recoveries ranging from 92.7% to 119.4% and relative standard deviations (RSD) between 0.6% and 8.4 % (n = 3), which is expected to the detection of CN– in other complex environments.