Simultaneous Quantification of Hg2+ and MeHg+ in Aqueous Media with a Single Fluorescent Probe by Multiplexing in the Time Domain

Development of a molecular probe for selective detection of MeHg+ in the presence of Hg2+ is a mission impossible to accomplish. Speciation analysis of two substrates with a single kinetic trace exploiting their differential reactivity toward a single probe, i.e., multiplexing in the time domain, is a cost-effective and powerful alternative. We have developed such a probe (Hg410) for simultaneously quantification of Hg2+ and MeHg+ in aqueous media. Hg410 is designed via the covalent-assembly approach, displays a zero background, and bears a very concise molecular construct. It has harnessed proximity-based catalysis to achieve high reactivity toward Hg2+ and MeHg+. An unprecedentedly low detection limit of ca. 4.6 pM and 160 pM was measured for Hg2+ and MeHg+, respectively.