Crafting Ultra–Sensitive and selective fluorescent probes for CH3Hg+ detection in groundwater: A 3–in–1 strategy

Abstract

Development of ultra–sensitive and selective fluorescent probes exclusively targeting CH3Hg+, especially against Hg2+, in real ecosystems like groundwater remains a critical yet formidable challenge. In this contribution, we present a series of fluorescent carbazole boronic acids (probes 1–4) designed for the highly sensitive and selective detection of Hg2+ and CH3Hg+ using an innovative 3–in–1 strategy. Notably, probe 4 exhibited exceptional performance in mercury detection in real groundwater, achieving a limit of detection concentration as low as 1.0 ppb for both Hg2+ and CH3Hg+, even in the presence of elevated levels of interfering cations or anions. Subsequently, a new fluorescent probe system was established by embedding probe 4 into cationic micelles, employing a microphase separation protocol. This resulted in exclusive selectivity towards CH3Hg+ over Hg2+ and other interfering ions with sensitivity as low as 10.0 ppb. This advancement not only addresses a critical gap in environmental monitoring but also demonstrates the potential for broader applications of these probes in sensitive detection methodologies.