Cysteine-based silver nanoparticles as dual colorimetric sensors for cations and anions

Abstract

We report herein the synthesis of silver nanoparticles (Ag NPs), their characterization, and anion and cation sensing properties. Freshly prepared amide–triazole Ag NPs (3a–Ag NPs and 3b–Ag NPs) could detect fluoride and cations such as Hg²⁺ and Cd²⁺ in aqueous media with a color change from pink to brown. The cysteine-based Ag NPs 5b–Ag NPs showed a colorimetric response towards H₂PO₄⁻, whereas 6–Ag NPs showed a colorimetric response towards H₂PO₄⁻ and HSO₄⁻ in aqueous media.