A rhodamine-based fluorescent probe for detecting Hg(2+) in a fully aqueous environment.

A water-soluble fluorescent probe for Hg(2+) based on a rhodamine B derivative was designed and synthesized. The new probe showed reversible colorimetric and fluorescent response to Hg(2+) in a fully aqueous solution. The probe exhibited real-time detection of Hg(2+) with high selectivity in media containing less than 1% organic cosolvent. Furthermore, bioimaging studies indicated that the new probe was cell permeable and suitable for the real-time imaging of Hg(2+) in living cells by confocal microscopy.