Ultrasensitive and rapid screening of mercury(II) ions by dual labeling colorimetric method in aqueous samples and applications in mercury-poisoned animal tissues

Rapid and ultrasensitive detection of trace heavy metal mercury(II) ions (Hg²⁺) are of significant importance due to the induced serious risks for environment and human health. This presented article reports the gold nanoparticle-based dual labeling colorimetric method (Dual-COLO) for ultrasensitive and rapid detection of Hg²⁺ using the specific thymine–Hg²⁺–thymine (T–Hg²⁺–T) as recognition system and the dual labeling strategy for signal amplification. Both qualitative and quantitative detections of Hg²⁺ are achieved successfully in aqueous samples. More importantly, the achieved detection limit of 0.005 ng mL⁻¹ (0.025 nM) without any instruments is very competitive to other rapid detection methods even ICP-MS based methods. This Dual-COLO method is also applied directly for real water sample monitoring and, more importantly, applied in analysis of mercury poisoned animal tissues and body fluidic samples, indicating a potentially powerful and promising tool for environmental monitoring and food safety control.