A Fluorescent Chemosensor for Hg2+ Based on a Rhodamine Derivative in an Aqueous Solution

In this paper, we unveil a novel rhodamine compound-based fluorescent chemosensor (compound 1) for fluorescent detection of Hg2+ in an aqueous solution. The fluorescence enhancement of compound 1 was attributed to the formation of a complex between compound 1 and Hg2+ by 1:1 complex ration (K = 8.0 x 10(4)), which has been utilized as the basis of fabrication of the Hg2+-sensitive chemosensor. A comparison of this method with some other fluorescence methods for the determination of Hg2+ indicated that this method has high selectivity and good water solubility. The analytical performance characteristics of the proposed Hg2+-sensitive chemosensor were investigated. The chemosensor can be applied to the quantification of Hg2+ with a linear range from 6.6 x 10(-7) to 2.4 x 10(-4) M and a detection limit of 1.3 x 10(-7) M. The experiment results show that the response behavior of compound 1 towards Hg2+ is pH independent in neutral conditions (pH 5.0 - 9.0). Most importantly, the fluorescence changes of the chemosensor are remarkably specific for Hg2+ in the presence of other metal ions, which meet the selective requirements for practical application. Moreover, the response of the chemosensor toward Hg2+ is fast (response time less than 1 mm). In addition, the chemosensor has been used for the determination of Hg2+ in river water samples with satisfactory results.