Plasmonic detection of mercury via amalgam formation on surface-immobilized single Au nanorods.
Au nanorods were used as plasmonic transducers for investigation of mercury detection through a mechanism of amalgam formation at the nanorod surfaces. Marked scattering color transitions and associated blue shifts of the surface plasmon resonance peak wavelengths (λmax) were measured in individual nanorods by darkfield microscopy upon chemical reduction of Hg(II). Such changes were related to compositional changes occurring as a result of Hg-Au amalgam formation as well as morphological changes in the nanorods' aspect ratios. The plot ofλmaxshifts vs.Hg(II) concentration showed a linear response in the 10-100 nM concentration range. The sensitivity of the system was ascribed to the narrow width of single nanorod scattering spectra, which allowed accurate determination of peak shifts. The system displayed good selectivity as the optical response obtained for mercury was one order of magnitude higher than the response obtained with competitor ions. Analysis of mercury content in river and tap water were also performed and highlighted both the potential and limitation of the developed method for real sensing applications.
Tyndall National Institute, Nanotechnology Group, University College Cork , Cork , Ireland.
Carola
C
Schopf
Tyndall National Institute, Nanotechnology Group, University College Cork , Cork , Ireland.
Alfonso
A
Martín
Tyndall National Institute, Nanotechnology Group, University College Cork , Cork , Ireland.
Daniela
D
Iacopino
105 Low-Dimension (1D/2D) materials; 204 Optics / Optical applications; 208 Sensors and actuators; 212 Surface and interfaces; 40 Optical, magnetic and electronic device materials; Gold nanorods; amalgam formation; darkfield microscopy; mercury detection; plasmonic