Mussel inspired redox surface for one step visual and colorimetric detection of Hg2+ during the formation of Ag@DOPA@Hg nanoparticles

[摘要] Inspired by the bioadhesive and redox properties of the 3,4-dihydroxy-phenylalanine (DOPA) contained in marine mussels, a facile, rapid and economic colorimetric strategy for Hg2+ detection was developed. The abundant catechol chains on the surface of Ag@DOPA can reduce Hg2+ to Hg0 and form a Ag@DOPA@Hg nanostructure with the deposition of Hg0. The nanostructures of Ag@DOPA and Ag@DOPA@Hg were confirmed by X-ray photoelectron spectroscopy, transmission electron microscopy, elemental mapping and Fourier transform infrared spectroscopy. The formation of the Ag@DOPA@Hg nanostructure causes a change in the color of the Ag@DOPA colloids from golden yellow to purple blue, making it directly possible to detect Hg2+ using a colorimetric strategy within 5 minutes. With increasing concentrations of Hg2+ from 10 nM to 4 μM, the surface plasmon resonance absorbance peak of the Ag@DOPA colloids decreased in intensity and exhibited a good linear relationship with the Hg2+ concentration. The limit of detection was determined as 5 nM. Furthermore, this response was found to be highly selective for Hg2+ as the absorption spectrum was not affected by other metal ions such as Pb2+, Cr3+, Cu2+, Al3+, Ni2+, Co2+, etc. The excellent stability, selectivity and sensitivity of this strategy offer analytical practicability for Hg2+ detection in real water samples with recoveries in the range of 104–105% and cosmetic samples with recoveries in the range of 85–103%.

[学科分类] 分析化学