Au(I)-Catenate-Directed Preparation of Polychrome Metal Nanoparticles for Heavy Metal Ion Discrimination

Heavy metal ions pose a significant threat to the environment and human health. Developing a highly sensitive heavy metal ion detection method is desirable. In this study, the Au(I)-catenates were formed in glucoamylase (Glu) and neomycin sulfate (Ne). The polychrome metal nanoparticles (MNPs) were prepared based on the template of Au(I)-catenates. The simple and ultrasensitive visual sensor array for the determination of heavy metal ions was established based on the color information extracted from polychrome MNPs. The addition of heavy metal ions shuttled among Au(I)-catenates in the strong alkaline solution. Through the use of the microwave heating method, the spherical and cubic MNPs of various sizes and colors were synthesized. To fully utilize the polychrome MNPs, a visual sensor was constructed for the detection and discrimination of eight heavy metal ions. The fingerprint-like color response signals correspond to each heavy metal ion and can be distinguished using computer software. The detection limit (0.1 nM) of heavy metal ions discriminated by the sensor is significantly lower than the data reported. The validation of the sensor was carried out by quantitative detection of Hg 2+ compared with its content in a certified reference material. This array method shows high sensitivity, good anti-interference, and potential in complex media.