A ratiometric and colorimetric fluorescent probe for the detection of mercury ion based on rhodamine and quinoline–benzothiazole conjugated dyad

Abstract Although fluorescent probes had become powerful tools to detect and image mercury ion (Hg2+), most of them suffered from a single signal change. Therefore, a new ratiometric fluorescent probe 1, with a quinoline–benzothiazole group as donor and a rhodamine as acceptor, was constructed for Hg2+ detection in this paper study. Results showed that Probe 1 was highly sensitive and selective to Hg2+, with a linear range of 0–26 μM and a detection limit (LOD) of 0.2 μM. Moreover, with excess competitive metal ions in DMF–H2O (v/v, 7/3), probe 1 exhibited excellent colorimetric selectivity and sensitivity to Hg2+ with the significant color change from colorless to pink with a linear range 0–28 μM and a LOD of 0.37 μM, because Hg2+ promoted the rhodamine hydrazide opening. And probe 1 finally was used to detect Hg2+ in living cells.