Rhodamine B Hydrazide Revisited: Chemodosimetric Hg²⁺-selective
Signaling Behavior in Aqueous Environments

摘要

The well-known Cu2⁺-selective chemodosimetric behavior of rhodamine B hydrazide was successfully switched to selectivity for Hg²⁺. The fluorescence signaling is remarkably selective toward Hg²⁺ ions compared to other common biologically and environmentally important metal ions, including Cu²⁺ ions. The detection limit was 0.2 レM in an acetate-buffered aqueous 10% methanol solution at pH 5. The OFF-ON type of signaling is due to the selective Hg²⁺-induced hydrolysis of the lactam ring of the hydrazide as has been reported for the standard Cu²⁺-signaling process of the same compound. A simple change in medium resulted in clear switching of selective signaling from Cu²⁺ to Hg²⁺, which extends the applicability of the easily accessible hydrazide derivative.