Colorimetric sensing of copper (Ⅱ) ions based on the inhibition of biocatalytic growth of gold nanoparticles

• Published in: Microchemical journal Vol. 157; p. 105015
• Main Authors: Guo, Caixin, Wang, Jinliang, Cheng, Jing
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2020
• Subjects: Enzymatic inhibition; Gold nanoparticles; Growth; Heavy metal ions detection; Sensor; Heavy metal ions detection; Growth; Enzymatic inhibition; Gold nanoparticles; Sensor
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/j.microc.2020.105015

[Display omitted] •The combination of the growth of gold nanoparticles (GNPs) with enzyme inhibition method for Cu2+ ions detection.•The selection of alcohol oxidase as the biocatalytic enzyme provides specificity of Cu2+ ions detection for this sensormakes this sensor specific for Cu2+ Cu2+ions.•This method provides a general strategy for the detection of other heavy metal ions by altering the type of enzyme. Colorimetric probes based on gold nanoparticles (GNPs) with the combination of enzymatic inhibition have been constructed for the purpose of determination of Cu2+ ions. In this method, the enzyme alcohol oxidase (AO) catalyzes the oxidation of methanol to yield hydrogen peroxide (H2O2), which induces the growth of GNPs by reducing AuCl4− to Au on the surface of GNPs. The biocatalytic growth of GNPs is retarded by Cu2+ ions because the activity of AO is inhibited in the presence of Cu2+ ions, enabling the colorimetric and spectroscopic assay of Cu2+ ions by the plasmon absorption band of GNPs. The GNP-based probes also present very high selectivity to Cu2+ ions even when the interfering metal ions are 10-fold excess. Moreover, this sensor exhibits a wide linear range of 1–100 ng/mL, with a detection limit of 0.84 ng/mL. Analysis of the real water samples revealed the practical application prospect of the GNP-based probes. The combination of the biocatalytic growth of GNPs and the effective enzymatic inhibition make this sensor simple, sensitive and visible to the naked eye for heavy metal ions detection.