The Design And Application Of Fluorescent Sensors For Mercury(Ⅱ) And Palladium(Ⅱ) Ions

Mercury and palladium, which are not degradable and hence can be concentrated through the food chain in the tissues of fish and marine mammals, finally enter to the human body. The high concentration of mercury or palladium will lead to protein inactivation. Up to now, many methods have been reported for the detection of those heavy metal ions. Optical sensors involving fluoroionophores are becoming popular because of their ease of application in solution as well as their high sensitivity to and selectivity for the analytes, especially in biological applications.Herein, we reported the design and application of four novel fluorescent chemodosimeters for Hg²⁺ and Pd²⁺.（1） A novel hemicyanine-based fluorescence turn-on chemodosimeter MS2 for Hg²⁺ by mercury triggered hydrolysis of the vinyl ether group has been reported. The probe has the unique advantages of easy preparation, good water solubility, excellent selectivity, high sensitivity, and fast response time（60 s） towards Hg²⁺ in aqueous solution. Furthermore, the probe is demonstrated to be qualified to detect Hg²⁺ in living cells.（2） A novel depropargylation-triggered spontaneous cyclization reaction based fluorescent turn-on chemodosimeter SPd1 for the detection of Pd²⁺ has been reasonably designed and developed. Based on the specific reactivity of palladium ions-promoted hydrolysis reaction, the probe exhibited a high selectivity and sensitivity for Pd²⁺. Furthermore, the probe was successfully used for fluorescence imaging of palladium ions in living cells.（3） A novel and simple depropargylation-triggered spontaneous cyclization reaction based fluorescent turn-on chemodosimeter SPd2 for the detection of Pd²⁺ has been reasonably designed and developed. Based on the specific reactivity of palladium ion-promoted hydrolysis reaction, the probe exhibited a high selectivity and sensitivity for Pd²⁺ with a low detection limit（53 nM, 5.7 μg/L） under physiological conditions in neutral PBS（only containing 1% organic cosolvent） without anyadditional reagents（4） A novel rhodamine-based fluorescent turn-on probe SPd3 for the detection of Pd²⁺ has been reasonably designed and developed. The probe exhibited a high selectivity and sensitivity with efficient fluorogenic and chromogenic sensing system for Pd²⁺ under mild conditions with a low detection limit（21 nM）. Furthermore, the probe was successfully used for fluorescence imaging of palladium ions in living cells.