Luminescence Properties Of Eu-schiff Base-phen-zn System And Its Applications

Trivalent rare earth cations with intricate optical properties havesignificant applications in various fields. With extensive development andutilization, they will inevitably penetrate into the environment, food chainsand organisms etc. In addition, Zn²⁺play important role in human health, themetabolic confusion of Zn²⁺may lead to some neurological diseases, likeParkinson’s disease, Alzheimer’s disease etc. Therefore it is a challeng task forthe determination of rare earth ions and Zn²⁺in the environment andorganisms. In this work, three new sensitive bifunctional quaternaryluminescence enhancement systems and one new sensitive ternaryluminescence enhancement system based on Schiff base were developedsuccessfully for the determination of trace amounts of Eu³⁺and Zn²⁺. Thedetails are as follows:1. A new sensitive bifunctional quaternary luminescence enhancementsystem was developed successfully for the determination of trace amounts ofEu³⁺and Zn²⁺. The luminescence intensity of Eu-N-（3-methoxysalicylidene）-2-aminopyridine system was greatly increased by the addition of1,10-phenanthroline and Zn²⁺ion in acetonitrile solution.Under optimal conditions, the luminescence intensity of the system showed alinear response toward Eu³⁺in the range of6.0×10^-62.5×10^-5mol L^-1witha detection limit down to2.0×10^-9mol L^-1, the influence of some rare earthcations were described. This method can be successfully applied to thedetermination of trace amounts of Eu³⁺in a high purity Gd₂O₃matrix. Inaddition, under the optimal conditions, the luminescence intensity of thesystem decreased linearly with the increase of Zn²⁺concentration, rangingfrom2.0×10^-61.8×10^-5mol L^-1with a detection limit of2.8×10-8mol L^-1.The influences of some common coexisting cations were investigated. Thismethod can also be successfully applied to the determination of trace amountsof Zn²⁺in a high purity Mg（NO3）2·6H2O matrix. The mechanism for energytransfer and luminescence enhancement of this quaternary system was alsostudied systematically.2. Two new Schiff base ligands（N-（o-vanilin）-1,8-diaminonaphthalene（NOVD） and N-vanilin-1,8-diaminonaphthalene （NVD）） were synthesized and two new sensitivebifunctional quaternary luminescence enhancement systems （①Eu-NOVD-Phen-Zn and②Eu-NVD-Phen–Zn） were developed successfully forthe determination of trace amounts of Eu³⁺and Zn²⁺. In the two systems theworking curves of Eu³⁺and Zn²⁺were obtained respectively. The linear rangesof Eu³⁺of two systems （①and②） were5.0×10^-62.0×10^-5mol L^-1and8.0 ×10^-63.2×10^-5mol L^-1，respectively, their detection limits were2.2×10^-9mol L^-1,2.7×10-8mol L^-1, respectively; The linear ranges of Zn²⁺of twosystems （①and②） were6.0×10-7¹.0×10^-6mol L^-1and3.0×10-7¹.0×10^-6mol L^-1, the detection limits were8.8×10^-10mol L^-1，9.9×10-11mol L^-1,respectively.3. A new Schiff base （N-（2-hydroxy-1-Naphthaldehyde）-1,8-diaminonaphthalene （NHND）） was synthesized, and a ternery luminescenceenhancement system （Eu-NHND-Phen） was developed successfully for thedetermination of Eu³⁺in the range of7.0×10-8³.2×10^-6mol L^-1， thedetection limit of Eu³⁺was7.5×10^-10mol L^-1.