Research Article
Plasmonic Sensing of Aqueous-Divalent Metal Ions by Biogenic
Gold NanoparticlesThe chemical interaction between biogenic gold nanoparticles (AuNPs) and several metal (II) ions can be regarded as a practical,
twofold, colorimetric, and plasmon resonance sensing method for the recognition of some divalent metal ions in aqueous
solutions. The green synthesized AuNPs, using Camellia sinensis as a reducing agent, were characterized by a surface plasmon
resonance (SPR) using UV-Vis spectroscopy, infrared spectroscopy, and transmission electron microscopy. The AuNP colloidal
solutions obtained have a pink-reddish color with SPRs centered between 529 and 536 nm. AuNPs with spherical, triangular,
and hexagonal shapes were found by TEM analyses. Despite their divergent morphologies, these AuNPs can be employed as
colorimetric and plasmon resonance sensors for detection of Ca2+, Sr2+, Cu2+, and Zn2+, primarily, in aqueous solutions.
Sensibility studies based on molar concentrations were also performed for these metal ions. Furthermore, solid biogenic
AuNPs/cellulosic biocomposites were prepared with the aim of developing portable, fast, and dependable colorimetric sensors;
nevertheless, these biocomposites resulted to be good adsorbent materials of metal ions
