Synthesis of polymer protected AuNPs for silver ions detection

Herein, a novel probe based on poly(N,N′-methylenebisacylamide) protected AuNPs (PDMAM-AuNPs) was developed for determination of silver ions. The thiol-terminated PDMAM was synthesized by the reversible addition fragmentation chain transfer radical polymerization. Then, the PDMAM-AuNPs were prepared by a simple, one-pot and green process. It has been observed that existence of the silver ions evoked a small red-shift to the emission peak of PDMAM-AuNPs and an obvious increase in UV absorption. The detection limit of the present method for silver ions was 0.5 μmol/L, with a linear range of 1.0–1000 μmol/L. Moreover, the possible mechanism for enhanced UV absorption intensity with enlarged diameter of PDMAM-AuNPs was explored and discussed briefly. The results demonstrated that silver ions could be detected by the PDMAM-AuNPs based colorimetric assays, further opening up new ways for the visualization and quantification of silver ions involved in our daily life.