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 5d¹⁰ 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 (R² = 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%∼108.06%, meaning that apt-AuNCs could be used as a promising probe to detect Hg²⁺ in complex food samples.