Silver Nanoclusters for the Multivariate Sensing of Mercury Ions and Bovine Serum Albumin via Two Independent Strategies

Abstract

Herein, silver nanoclusters (FO-Ag NCs) were synthesized using folic acid and O-phenylenediamine as ligands, with an emission at 578 nm when excited at 410 nm. The FO-Ag NCs achieved multivariate determination for Hg2+ and bovine serum albumin (BSA) via two strategies. Initially, Hg2+ quenched the emission, while BSA enhanced it with a blue shift (578 to 558 nm), with detection limits (LOD) of 96 nM and 0.60 μM, respectively. Another strategy, cascade detection based on BSA recovering the Hg2+ quenched emission, was accomplished with an LOD of 1.26 μM for BSA. These two strategies ensured the sensing accuracy by self-calibration. The smartphone supporting portable sensing enabled rapid on-site analysis in food and water with satisfied recoveries (94.22–106.09% for Hg2+ and 97.31–112.51% for BSA), and the reliability was confirmed by ICP-MS and ELISA. The multivariate sensing protocol demonstrated potential applications for environmental monitoring and food safety.