A fluorescent probe based on aptamer gold nanoclusters for rapid detection of mercury ions

The mercuric ion (Hg2+) is a hazardous pollutant that is widely distributed in living organisms, foods, and environments with highly toxic and bio-accumulative properties. In the present study, a fluorescent probe based on aptamer gold nanoclusters (apt-AuNCs) was prepared for the ultrasensitive detection of Hg2+ in food. The principle underlying the prepared probe was the quenching of the fluorescence of apt-AuNCs in the presence of Hg2+ due to the strong metallophilic interactions between the 5d(10) centers of Hg2+ and Au+. Under optimal conditions, the proposed fluorescent probe exhibited a linear relationship with Hg2+ concentration within the range of 2-200 nM (R-2 = 0.9960). In addition, the limit of detection (LOD) was 0.0158 nM, which is below the Chinese standard value of 25 nM for Hg2+ in food. Furthermore, the apt-AuNCs were applied to detect Hg2+ in spinach and crawfish samples, with recovery percentages of 91.99%& SIM;108.06%, meaning that apt-AuNCs could be used as a promising probe to detect Hg2+ in complex food samples.