The Development Of Novel Fluorescence Probes Based On Rhodamine And Their Application In Environmental Analysis

Accompanied by environmental pollution become a sever challenge to our society, the mornitoring and analyzing methods of environmental pollutants have become a focus point in current environmental science field. Heavy metals pollutionis already in a sever situation, itsenormous damage to environment and health can not be ignored. Hypochlorous acid is widely used due to its antibacterial property, however, abuse using will cause environmental pollution and result to a variety of harmful diseases in organisms. Therefore, the qualitative and quantitave analysis of mercury ion and hypochlorous acid in environment and living cells is of great importance to environmental protection.In order to improve the probe performance in sensitivity, selectivity and its application in environmental and biological systems, we successfully designed and synthesized three probes based on rhodamine and applied them to mornitor mercury ion, hypochlorous acid in real samples and living cells, respectively.（1） 2-carboxybenzaldehyde rhodamine B thiohydrazine（RBSH） was designed,synthesized and successfully employed to detect Hg²⁺ in real samples and living cells by fluorescence imaging techniques. In test system, RBSH solution is colourless with very weak fluorescence; after mercury ions joining, the lactam ring open, solution became pink and fluorescence exhibited over 83-fold enhanced(1.0equiv. of Hg²⁺). The probe also has wide working pH range and rare response to other ions, proving that the probe aiming at mercury ions have high selectivity and high sensitivity. Fluorescence spectrum shows RBSH has good linearity between10-7 and 10-5M and its detection limit is 4.15 × 10-8 M. Meanwhile, the proposed probe was used in real water samples and HepG2 cells for Hg²⁺ fluorescence imaging and achieved satisfactory results.（2）Rhodamine 101 thiolactone（R101S） was designed, synthesized and used to detect Hg²⁺ in real water samples and living cells with satisfied results. Under the induction of Hg²⁺, the test system solution color change from colorless to pink,accompanied the fluorescence intensity significantly enhanced. When added thesame equiv Hg²⁺ with probe in the system, the fluorescence intensity enhanced68-fold. The probe shows good linearitybetween 10-7 and 10-5 M of Hg²⁺and the detection limit is 4.0×10-8 M.Finally,the probe was successfully applied for Hg²⁺detection in real water samples and HePG2 cells.（3）The rhodamine101 thiosemicarbazide（R101TSC） probe for hypochlorous acid was designed and synthesized, and then probe R101 TSC was used for fluorescence imaging in environmental samples and cells because of the fanstastic membrane permeability and the working pH range contain physiology pH. The probe was linearly proportional to the concentration of HOCl in the range of10-6¹0-5 M and the detection limit is 0.3mM. Under the same equiv. of HOCl, the test system solution color changed from colorless to pink, along with the fluorescence intensity dramatically enhanced（25-fold）. Moreover, the proposed probe was successfully used for the detection of hypochlorous acid in water samples and HepG2 cells by fluorescent imaging.