Potential-resolved Electrochemiluminescence Chiral Sensors For Simultaneous Detection Of Dual Targets

Chiral molecules play an important role in the fields of medicine,pesticides and biochemical technology.The enantiomers with different configurations may have opposite physiological effects.Therefore,it is of great significance to develop a novel technique of chiral detection with simple,efficient and higher sensitivity.In this study,four new electrochemluminescence（ECL）materials have been synthesized to realize simultaneous quantitative ECL recognition for different chiral molecules.Anode and cathode luminescent materials were bonded into a chiral composite and constructed as chiral ECL sensor,which derived from the discovery of the difference between peak potential of chiral materials and corresponded different chiral molecules.The strategy successfully achieved the potential-resolved ECL chiral simultaneous detection for dual targets.The main research work of this paper is as follows:（1）Based on the excellent luminescence ability of rare earth ruthenium complex,the present study successfully transformed chiral Ru（phen）₂Cl₂ into two new chiral complex Ru（phen）₂L-Cys and Ru（phen）₂L-Asp.The morphology and structure of the materials were verified by SEM,FT-IR,TG,¹H NMR,XPS and CD,etc.Cyclic voltammetry（CV）and electrochemical impedance spectroscopy（EIS）analysis showed that the two chiral materials have good electrical conductivity.Two ECL chiral sensors constructed using the two chiral materials were used to detected a series of enantiomers.It was found that Ru（phen）₂L-Cys and Ru（phen）₂L-Asp respectively showed good quantitative recognition ability,stability and reproducibility for D/L-phenylalanine（D/L-Phe）and D/L-penicillamine（D/L-Pen）enantiomers.（2）ZnO nanorods have been recognized as good ECL cathode luminescent materials.In prensent study,ZnO nanorods array on a tin oxide（FTO）conductive glass doped fluorine was synthesized by electrochemical deposition.Thin layer crystals of chiral Zn（4,4’-bipy）（L-tar）MOF were in-situ grew on the nanorods array using the ZnO nanorods as zinc source.The morphology,structure and chirality for ZnO@Zn（4,4’-bipy）（L-tar）nanorods array were confirmed by SEM,XRD,FT-IR and UV-Vis.The constructed ECL chiral sensor with the composite has good electron transmission ability proved by CV and EIS test.The ECL chiral detection for a series of enantiomers showed that the sensor has good recognition effect,stability and reproducibility for menthol enantiomers（D/L-Men）.The research results showed that ZnO@Zn（4,4’-bipy）（L-tar）nanorods effectively recognize D/L-Men enantiomers at-1.7 V,and Ru（phen）₂L-Cys effectively recognize D/L-Phe at+1.3V.Based on these,a novel ECL chiral sensor,namely Ru（phen）₂L-Asp/ZnO@Zn（4,4’-bipy）（L-tar）/FTO was constructed.The sensor showed good quantitative dual recognition ability for D/L-Men和D/L-Pen enantiomers.（3）The non-chirality of ZnO nanorods limits their application in chiral recognition although these are typical ECL cathode luminescent nanomaterials.In present study,the integrated spiral ZnO nanocrystalline flowers with spatial chiral configuration on a FTO was prepared through a process called inducted method by D-or L-methionine using hydrothermal and burning mathod.The process is simple,rapid,non-toxic without the introduction of chiral ligands.SEM,FT-IR,XRD,CD and UV-Vis demonstrated the morphology and structure of ZnO nanocrystals and chirality.The ECL chiral sensor was constructed with synthesized ZnO nanoflowers/FTO.The ECL test for a series of amino acid enantiomers showed that the chiral sensor has good quantitative recognition stability and reproducibility on D/L-Asp enantiomers.The study showed that ZnO nanoflowers effectively recognize D/L-Asp enantiomers at-1.7 V,and Ru（phen）₂L-Cys effectively recognize D/L-Phe at+1.3V.Based on these,a new ECL chiral sensor,namely Ru（phen）₂L-Cys/ZnO nano-flower/FTO was constructed.This performed good quantitative dual recognition ability for D/L-Asp and D/L-Phe enantiomers.To realize simultaneous recognition for two enantiomers through the potential resolved ECL route,the study combine for the first time two potential resolved chiral ECL materials into a chiral ECL composite and used to build ECL chiral sensor and showed good stability and quantitative analysis ability.The strategy provides a new route for simultaneous recognition of multi-target objects in the future.This is also important for promoting the chiral sensing of multi-flux ECL detection.