Study On The Synthesis And Application Of Copper Ion Fluorescent Probe Based On Ninhydrin

Cu²⁺plays an important role in our life,production and physiological activities.However,the overload of Cu²⁺in organisms and environment could cause serious effects and harms.Therefore,it is of great significance to detect Cu²⁺.Due to the characteristics of simple equipment,convenient operation,rapid response and high sensitivity,fluorescence analysis based on probe has gradually become an important means for Cu²⁺detection.Although many Cu²⁺fluorescent probes have been designed,there are still some shortcomings,such as complicated synthesis steps,complex structure,poor water solubility,and so on.Ninhydrin has the rigid plane and good water solubility,and it was able to easily react with amino compounds.Up to date there are only a few reports about ninhydrin-based fluorescent probe.In this thesis a quenched fluorescent nanoprobe and an enhanced fluorescent probe for Cu²⁺detection were respectively synthesized from ninhydrin,and their fluorescence performances and responses to Cu²⁺were investigated.In the first chapter,we reviewed the composition and recognition principle of fluorescent probe,and the research progresses of quenched Cu²⁺fluorescent probe,enhanced Cu²⁺fluorescent probe and ratiometric Cu²⁺fluorescent probe.In the second chapter,we synthesized a water-soluble and quenched Cu²⁺fluorescent nanoprobe?PEIN?via the reaction between PEI and ninhydrin at room temperature for 1 hour.In aqueous solution with p H value of 5.0,specific recognition of Cu²⁺by PEIN occurred resulting from static quenching,which has been used for detecting Cu²⁺with the detection limit of 0.41?M.After the addition of EDTA or Cys,the fluorescence of PEIN-Cu²⁺system was restored,and the fluorescence"on-off-on"conversion was realized.In the third chapter,we synthesized a simple and enhanced Cu²⁺fluorescent probe L from hydroquinone and indene three ketone.In p H 7.0 HEPES buffer system,probe L could recognize Cu²⁺with good selectivity and high sensitivity.A good linear relationship was obtained between the concentration of Cu²⁺ranging from 2 to 120?M and the fluorescence change of the probe,and the detection limit reached 5.50×10^-8 M.The recognition mechanism of L and Cu²⁺was preliminarily investigated.The results indicated probe L and Cu²⁺formed a 1:1 complex during the sensing process,and the buffer system played a crucial role in fluorescence enhancement behavior.