Selective Detection of Cysteine and Hg²⁺ by a Carboxylatopillar[5]arene‐Based Silver Nanoparticles in Water Milieu

Abstract The ligand‐protected nanoparticles for the colorimetric detection of ions and molecules have been used as a simple analytical method in many research fields, including biology. The incorporation of organic moieties onto the nanoparticle surface affords both stability and desirable surface functionalization to the nano‐entities. In this study, we report the synthesis, characterization, and receptor properties of silver nanoparticles derived from carboxylatopillar[5]arene ( AgPAA ) in water milieu by severalspectral and microscopic techniques. It has been found that AgPAA selectively detects Cys among twenty proteinogenic amino acids and Hg 2+ among the 14 cations studied by UV–visible spectroscopy and visual color changes. The aggregation of AgPAA upon the addition of Cys and Hg 2+ has been confirmed by TEM studies. The detection limits of 13 × 10 −6 and 41 × 10 −6 M were obtained for AgPAA with Cys and Hg 2+ , respectively, based on UV–visible spectral studies.