A New Spiropyran-Based Sensor for Colorimetric and Fluorescent Detection of Divalent Cu and Hg Ions and Trivalent Ce, Cr and Al Ions.

A new spiropyran derivative acts as colorimetric and fluorescent sensor for metal ions. Addition of Cu, Al, Cr and Ce to the sensor solution brings about marked increase in the absorption intensities while addition of other metal ions (Na, K, Li, Sr, Hg, Zn, Co, Ni and Ag) fails to cause substantial change in the UV-Vis spectra. The sensor can be used for detection of Hg, Cu, Ce, Cr and Al ions by the naked eye and by fluorescence enhancement. The detection limit of Cu and Hg ions by the sensor is estimated to be 10 and 14 μM, respectively. Job's plot analysis on the sensor-Cu complexation reveals the formation of a 2:1 stoichiometric complex between the sensor and Cu ion.