A Facile Preparation of a New Water-Soluble Acridine Derivative and Application as a Turn-off Fluorescence Chemosensor for Selective Detection of Hg.

A new acridine-based chemosensor was prepared, characterized and investigated for quantitative detection of Hg ions in aqueous solutions. DFT and TD-DFT calculations showed that formation of a coordination bond between Hg and the thiolate-sensor accounts for the fluorescence quenching, forming [HgLCl] as the most stable species. Limit of detection and limit of quantification were as low as 4.40 and 14.7 μmol L, respectively (R = 0.9892, least squares method), and a linear concentration range of 14.7-100 μmol L. Benesi-Hildebrand and Job formalisms are in accordance with the formation of a stable complex with a 1:1 (metal ion/sensor) ratio, and a determined binding constant of 5.14 × 10 L mol. Robustness was verified based on the variation of several analytical conditions. In addition, the method presented maximum relative standard deviation of 4.6%, and recovery results was (90.3 ± 4,6)% from distilled water, with no effect of interfering ions. Analytical figures of merit showed that the sensor can be an attractive low cost alternative for detection of Hg.