Thiamine-functionalized silver nanoparticles for the highly selective and sensitive colorimetric detection of Hg2+ ions

Abstract

Hg²⁺ contamination is a serious threat to the environment; hence, the development of methods for its trace level detection is urgently required. To contribute in this domain, we report for the first time the application of a highly sensitive and selective colorimetric sensing platform for Hg²⁺ ions using thiamine-functionalized silver nanoparticles (Th-AgNPs). Upon the addition of Hg²⁺ ions to the solution, the AgNPs exhibited a noticeable color change from yellow to violet-blue. This color change was monitored by the UV-vis spectrophotometric observation of a significant decrease in the absorption band at 395 nm along with the appearance of a new peak at 550 nm. The designed sensor demonstrated good sensitivity in the concentration range of 1 × 10⁻⁸ to 5 × 10⁻⁶ M with a detection limit of 5 nM. The sensor also showed high selectivity for Hg²⁺ when tested in the presence of several competing metal ions. Moreover, the method was found to be applicable to river water samples with satisfactory percentage recoveries.