Enhanced Luminescence Systems Of Schiff Base-Phen-Eu And Their Applications

Trace amounts of Eu³⁺was determined through luminescence analysismethod in this work. The luminescence properties and applications ofluminescence systems of Schiff base-Phen-Eu or Zn-Schiff base-Phen-Euin solution were investigated systematically. Compared with the reportedmethods of the determination of trace amounts of Eu³⁺, luminescenceanalysis method is sensitive, fast, reproducibile, and low costs. The majorresuts of this work consist of the following four parts:(1) The investigation of UV-vis spectra indicated that the Schiff base ligandN-(3,5-dibromo-salicylidene)-2-amino pyridine (HL) and Eu³⁺ions canform stable complex in the acetonitrile solution. The luminescence intensityof HL-Eu was greatly enhanced by the addition of1,10-Phenanthroline(Phen) in the acetonitrile solution. Under the optimal conditions, theluminescence intensities of Eu-HL-Phen varied linearly with theconcentration of Eu³⁺in the range of4.0×10^-62.4×10^-5mol L^-1with adetection limit of0.43×10^-9mol L^-1. The interferences of some rare earthions were described.This method was applied successfully to thedetermination of trace amounts of Eu³⁺in a high purity Gd₂O₃matrix. Themechanisms of the energy transfer and luminescence enhancement in theternary system was studied systematically. The energy gap between thelowest triplet energy levels of HL or Phen and the resonant energy ofEu³⁺(⁵D₁) exists in the optimal value (3000±500cm-1), therefore HL is asuitable sensitizer for the luminescence of Eu³⁺.(2) A new ternary luminescence enhancement system was establishedsuccessfully for the determination of Eu³⁺. The luminescence intensity of N,N'-2(2-hydroxy-1-naphthaldehyde)-2,6-diamino pyridine (HNDP)-Euwas greatly enhanced by the addition of1,10-Phenanthroline (Phen). Underthe optimal conditions, the luminescence of Eu-HNDP-Phen intensitiesvaried linearly with the concentration of Eu³⁺in the range of2.5×10^-61.2×10^-5mol L^-1with a detection limit of1.4×10^-9mol L^-1. The interferences of some rare earth ions and other common ions were described.This method was applied successfully to the determination of trace amountsof Eu³⁺in a high purity Y₂O₃matrix. The mechanisms of the energytransfer and luminescence enhancement in the ternary system were studiedsystematically. The energy gap between the lowest triplet energy levels ofHNDP or Phen and the resonant energy of Eu³⁺(⁵D₁) exists in the optimalvalue (3000±500cm-1), therefore both HNDP and Phen are a suitablesensitizer for the luminescence of Eu³⁺.(3) A new ternary luminescence enhancement system was establishedsuccessfully for the determination of Eu³⁺. The luminescence intensity ofN,N'-2(vanillin)-2,6-diamino pyridine (DVDP)-Eu was greatly enhancedby the addition of1,10-Phenanthroline (Phen). Under the optimal conditions,the luminescence intensities of Eu-DVDP-Phen varied linearly with theconcentration of Eu³⁺in the range of3.0×10^-6mol L^-13.4×10^-5mol L-1with a detection limit of0.46×10^-9mol L^-1. The interferences of somerare earth ions were described.This method was applied successfully to thedetermination of trace amounts of Eu³⁺in a high purity Y₂O₃matrix. Themechanisms of the energy transfer and luminescence enhancement in theternary system was studied systematically. The energy gap between thelowest triplet energy levels of DVDP or Phen and the resonant energy ofEu³⁺(⁵D₁) exists in the optimal value (3000±500cm-1), therefore bothDVDP and Phen are a suitable sensitizer for the luminescence of Eu³⁺.(4) A new ternary luminescence enhancement system was establishedsuccessfully for the determination of Eu³⁺. The luminescence intensity of N,N'-2(indolinedione)-2,6-diamino pyridine (IDDP)-Eu was greatlyenhanced by the addition of1,10-Phenanthroline (Phen). Under the optimalconditions, the luminescence of Eu-IDDP-Phen intensities varied linearlywith the concentration of Eu³⁺in the range of5.0×10^-8mol L^-11.3×10^-6mol L^-1with a detection limit of0.47×10^-8mol L^-1. The interferences ofsome rare earth ions were described.This method was applied successfully tothe determination of trace amounts of Eu³⁺in a high purity Y₂O₃matrix.The luminescence properties of Eu-IDDP-Phen-Zn quaternary system wasstudied. Under the optimal conditions, the luminescence intensities of Eu-IDDP-Phen-Zn varied linearly with the concentration of Zn²⁺in the range of2.5×10^-6mol L^-12.5×10^-5mol L^-1with a detection limit1.3×10^-8mol L-1. The interferences of some transition metal ions were described.Thismethod was applied to the determination of trace amounts of Zn²⁺in aCu(NO₃)₂matrix. The mechanisms of the energy transfer and luminescenceenhancement in the ternary system was studied systematically. The energy gap between the lowest triplet energy levels of IDDP or Phen and theresonant energy of Eu³⁺(⁵D₁) exists in the optimal value (3000±500cm-1),therefore both IDDP and Phen are a suitable sensitizer for the luminescenceof Eu³⁺.