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 Hg(2+) in an aqueous solution. The fluorescence enhancement of compound 1 was attributed to the formation of a complex between compound 1 and Hg(2+) by 1:1 complex ration (K = 8.0 × 10(4)), which has been utilized as the basis of fabrication of the Hg(2+)-sensitive chemosensor. A comparison of this method with some other fluorescence methods for the determination of Hg(2+) indicated that this method has high selectivity and good water solubility. The analytical performance characteristics of the proposed Hg(2+)-sensitive chemosensor were investigated. The chemosensor can be applied to the quantification of Hg(2+) with a linear range from 6.6 × 10(-7) to 2.4 × 10(-4) M and a detection limit of 1.3 × 10(-7) M. The experiment results show that the response behavior of compound 1 towards Hg(2+) is pH independent in neutral conditions (pH 5.0-9.0). Most importantly, the fluorescence changes of the chemosensor are remarkably specific for Hg(2+) in the presence of other metal ions, which meet the selective requirements for practical application. Moreover, the response of the chemosensor toward Hg(2+) is fast (response time less than 1 min). In addition, the chemosensor has been used for the determination of Hg(2+) in river water samples with satisfactory results.