Sensitive Detection of Hg²⁺ with Switchable Electrochemiluminescence Luminophore and Disposable Bipolar Electrode

Abstract

Abstract A novel paper‐based bipolar electrode‐electrochemiluminescence (pBPE‐ECL) switch system was used for the rapid, label‐free, and sensitive detection of Hg 2+ . In the proposed approach, Hg 2+ selectively mediates two thymine‐enriched single‐stranded DNA probes to form double‐stranded DNA (dsDNA). In the presence of Hg 2+ , the “light‐switch” molecule [Ru(phen) 2 dppz] 2+ can freely intercalate into the base pairs of the dsDNA, resulting in intense ECL emission. The assay takes advantage of the wireless pBPE‐ECL platform to yield a low‐cost, disposable, and sensitive analysis. The system has a limit of 0.1 nM for Hg 2+ detection. We also showed that the system can be used to distinguish Hg 2+ over other metal ions, including Pb 2+ , Zn 2+ , Cu 2+ , Ba 2+ , Co 2+ , Cd 2+ , Fe 3+ , Mn 2+ , and Li + . Moreover, the proposed approach was rapid, low‐cost, and label‐free for effective sensing of Hg 2+ in drinking and lake water.