Ultrasensitive detection of silver(I) ions based on water-soluble micellized phosphorescent silver nanoclusters co-protected by 1,3-benzenedithiol and triphenylphosphine

Silver ion (Ag+) is one of the most toxic and dangerous heavy metal pollutants. Therefore, finding a simple, sensitive and selective approach to detect Ag+ is very urgent for environmental protection and risk reduction to human health. In this work, water-soluble red-emitting micellized phosphorescent silver nanoclusters (Ag-29 @Na micelles) with a large stokes shift of 380 nm are prepared and used as sensitive and selective phosphorescent probes to realize the rapid and simple detection of Ag+. Upon adding Ag+, the phosphorescence of Ag-29 @Na micelles is quenching, and the phosphorescence quenching ratio is linearly proportional to the Ag+ concentration over the range from 1 nM to 100 nM with the detection limit of 0.8 nM (S/N = 3). The Ag-29 @Na micelles exhibit high selectivity for Ag+ over other potentially interfering metal ions. The quenching mechanism of Ag-29 @Na micelles by Ag+ is studied in details using various analytical characterizations including UV-vis absorption spectroscopy, photoluminescence lifetime, X-ray photoelectron spectroscopy, transmission electron microscopy, and zeta potential, and the results denote that the aggregation between Ag-29 @Na micelles and Ag+ is responsible for the phosphorescence quenching. The Ag-29 @Na micelles-based phosphorescence probes are successfully applied to detect Ag+ in lake water samples with good recoveries of 98 %-108 %.