A Single Fluorescent Sensor for Hg(2+) and Discriminately Detection of Cr(3+) and Cr(VI)

An iminocrown ether was synthesized and its fluorescence properties were studied in the presence of a variety of cations and anions in 99 % aqueous medium. The results revealed the interesting ability of the iminocrown ether in discriminately detection of Cr(III) and Cr(VI) ions in addition to detection of Hg(2+) ion. Among various environmentally relevant metal ions, Cr(3+) and Hg(2+) enhanced and quenched the fluorescence emission, respectively and among anions only dichromate ion, Cr(VI), quenched the emission while the rest of ions insignificantly influenced the fluorescence emission. Selectivity of the iminocrown ether was also investigated and proved in the presence of excess of common competing ions. Furthermore, the fluorescence intensity of the iminocrown ether was studied as a function of concentrations of the three ions by performing a titration experiment for each one of them. The detection limits of 5.36 × 10(-8), 2.06 × 10(-6), and 7.49 × 10(-8) mol L(-1) were also calculated for Hg(2+), Cr(3+), and Cr(VI), respectively.