| Electrochemiluminescence as a versatile analytical technology has attracted considerable attention in recent years,which is often for the applications in the fields of food analysis,biochemical analysis,environmental monitoring and clinical diagnostics.It combines the highly sensitivity of chemiluminescence and the distinctive advantages of electrochemistry with the ability to control the potential.Until now,most of ECL luminescence reagents are classic pyridine ruthenium,quantum dots,and luminol,therefore,it is interesting work to explore new high efficient ECL reagents.In this paper,four terbium complexes have been synthesized with terbium ion as the central ion and2-pyrazinecarboxylic acid,pyrazine-2,3-dicarboxylic acid,pyrazine-2,5-dicarboxylic acid and pyrazine-2,6-dicarboxylic acid as ligands,respectively.Moreover,we discussed their ECL properties.Specific work is divided into three parts:1.A new lanthanide terbium complex{Tb?pzda?3?NO3?3·nH2O}has been synthesized by hydrothermal method and characterized by Fourier transform infrared spectroscopy?FT-IR?and energy-dispersive X-ray spectroscopy?EDS?.It has been found that the synthesized Tb?pzda?3?NO3?3·nH2O shows good electrochemiluminescence?ECL?behavior in the presence of triethanolamine?TEOA?at HAc-NaAc buffer solution.The possible reaction mechanism has also discussed based on the fluorescence spectra and ECL spectra.For sensing application,it was found that protocatechuic acid?PCA?had an obvious quenching effect on the ECL signal of Tb?pzda?3?NO3?3·nH2O,and resulted in a decreased ECL signal associated with the concentration of PCA.Therefore,a high sensitivity method for the detection of PCA was established with a linear range of1.283×10-1010 M3.845×10-4 M and a detection limit of 0.085 nM.2.Three lanthanide terbium complexes with terbium ion as the central ion and pyrazine-2,3-dicarboxylicacid,pyrazine-2,5-dicarboxylicacidand pyrazine-2,6-dicarboxylic acid as ligands were successfully synthesized by hydrothermal method and characterized by FT-IR and EDS.The electrochemiluminescence properties of the three complexes were also explored,and it discovered that the synthesized three complexes showed good electrochemiluminescence?ECL?behaviors in the presence of triethanolamine?TEOA?at HAc-NaAc buffer solution,and the ECL intensity of Tb?H2pzda?3?NO3?3·nH2O is better than the other two.It was found that isovanillic acid?IVA?had an obvious quenching effect on the ECL signal of Tb?H2pzda?3?NO3?3·nH2O.Based on this,a new method for the detection of IVA was established with a linear range of 1.189×10-10 M1.189×10-44 M and a detection limit of 0.079nM.3.We studied the ECL property of Tb?pzdc?3?NO3?3·nH2O-TEOA and Tb?Hpzda?3?NO3?3·nH2O-TEOA.The possible ECL mechanism was inferred by cyclic voltammety,fluorescence spectra and ECL spectra.On the basis of previous experiments,we discussed the ECL property of four complexes were related to the ligands structure.The ECL intensity of four complexes in the presence of TEOA at HAc-NaAc buffer solution was compared in the same conditions.Some rules of ECL intensity of four complexes are related to the number and located of carboxyl groups are summarized.And it provides some suggestions for synthesizing ECL reagents with excellent properties. |
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