Detection of Hg2+ in Aqueous Media by A New Xanthene Based Schiff Base Sensor

A xanthene-based colorimetric sensor, 2-((5-chloro-2-oxoindolin-3-ylidene)amino)-3',6'-bis(diethylamino)spiro[isoindoline-1,9'-xanthen]-3-one, was designed and its metal sensing properties was evaluated in aqueous solutions. The sensor showed colorimetric response toward Hg2+ from colorless solution to pink among various metal ions such as Na+, K+, Mg2+, Ca2+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Al3+, Cd2+ and Pb2+. The addition of Hg2+ exhibit an absorption enhancement of the sensor based on a spirocycle ring‐opening process and a subsequent hydrolysis reaction. The detection limit of the sensor for Hg2+ was found to be 7.88×10−8 M.