Dual-Probe SERS Chip:A Rapid and Ratiometric Detectionof Trace Hg²⁺ in Food Samples

Rapidly and accurately identifying ultratrace mercury ions (Hg²⁺) to protect people’s lives and health is still challenging work. A dual-probe ratiometric SERS chip was developed by growing spiderweb-like Au nanowires (AuNWs) on an AuNP array, enhancing SERS signals and selectivity for trace Hg²⁺ detection. Due to the strong coordination ability of Hg²⁺ to form Au-SH bonds, 4-mercaptobenzoic acid (4-MBA) was replaced by the adsorption of 4-aminothiophenol (4-ATP), thereby creating a sandwich structure (Au/Hg²⁺/4-ATP). Moreover, the sensor exhibits excellent anti-interference capabilities, high selectivity, and rapid detection within 3 min, with a wide linear detection range of 10^–3 to 10^–11 M and a low detection limit of 1.35 × 10^–13 M. It has been successfully used to detect Hg²⁺ in fish, offering a rapid and reliable method for on-site heavy metal monitoring and mitigating mercury-related risks.