Recent Advances (2019–2025) in Mercury Ion Detection

As a persistent bioaccumulative toxin, mercury ion (Hg²⁺) presents grave environmental and public health risks due to their extreme toxicity and neurological damage potential. The advancement of reliable Hg²⁺ detection methodologies become imperative for safeguarding ecological security and food supply chains. In recent years, different signal output modes have been explored for Hg²⁺ detection. This review systematically summarizes the latest detection techniques and strategies for Hg²⁺ based on electrochemical signal, fluorescence signal, SERS signal and colorimetric signal. Innovation designs of functional materials, small molecules, nanoprobes and strategies for Hg²⁺ detection have been introduced and their detection performances including sensitivity, selectivity and portability are compared with each other. The comparison results show that some methods can achieve ultrasensitive detection of Hg²⁺ at fM level. In addition, the challenges and perspective for Hg²⁺ detection have been discussed. The review is expected to provide insights for the development of highly sensitive and portable detection tools for Hg²⁺, and promote the transformation of Hg²⁺ detection technology from the laboratory to industrialization.