Application Of Rare Earth-DTPA-Base Complexes In Detecting Base Matabolites In Urine

In recent years,fluorescent probe detection method has been widely used in many important fields such as biology,medicine and chemistry due to its advantages of simple equipment,easy operation and fast analysis speed.Because chemiluminescence does not require the use of any light source other than excitation light,there is no need to worry about interference with the background light source when fluorescence detection or fluorescence imaging is performed for chemiluminescence imaging with a fluorescent probe,so that a lower detection limit can be obtained.In this paper,based on the structural characteristics of the detected molecules orotic acid（OA）and xanthine（Xe）and combined with the special coordination properties of rare earth metal ions,the complex Eu^III-dtpa-BA was designed and synthesized to detect OA in urine.At the same time,the complexes Tb^III-dtpa-2A,Tb^III-dtpa-2C and Tb^III-dtpa-AC were synthesized to detect Xe in urine,and the differences of three complexes in the detection of Xe were compared.In addition,all synthesized ligands were characterized by FT-IR,elemental analysis,¹H NMR and¹³C NMR in this paper.The influences of solution pH values and the existence of possible coexisting substances on the detection were investigated.Finally,the linear relationships were determined and the corresponding detection mechanism is proposed.The specific content is divided into the following two parts:1.In the first part,according to the structural characteristics of OA,the dtpa-BA was synthesized by the acylation reaction between dtpa anhydride and adenine based on the RNA single stranded base sequencing principle.Then,the Eu³⁺with nine coordination characteristics was coordinate with dtpa-BA to obtain the complex Eu^III-dtpa-BA for the detection of OA in urine.We also studied the effect of solution pH values on OA detection.Under the optimal solution pH value,the fluorescence intensity of Eu^III-dtpa-BA decreased with the increase of OA concentration.In addition,the presence of coexisting substances in urine,such as uric acid（UA）,hippuric acid（Hipa）,creatinine（Cre）,histidine（His）and ascorbic acid（AA）does not interfere with the detection of OA.Finally,we successfully applied Eu^III-dtpa-BA to detect OA in real urine.According to the experimental results,we analyzed and described the mechanism of using Eu^III-dtpa-BA as fluorescent probe to detect OA.2.In the second part,according to the structure of the detected substance Xe,based on the DNA single stranded base sequencing principle,three ligands dtpa-2A,dtpa-2C and dtpa-AC were synthesized by modifying dtpa with adenine and cytosine,respectively.The Tb³⁺with nine coordination properties was then coordinated with the three ligands to synthesize three complexes Tb^III-dtpa-2A,Tb^III-dtpa-2C and Tb^III-dtpa-AC for the detection of Xe in urine.In this section,we studied the effect of solution pH values on the fluorescence intensities of the three complexes,respectively.At the same time,we also explored the fluorescence intensities of the three complexes as a function of Xe concentration.The fluorescence intensity of Tb^III-dtpa-2A decreased gradually with the increase of Xe concentration,while the fluorescence intensities of Tb^III-dtpa-2C and Tb^III-dtpa-AC gradually increased with the increase of Xe concentration.We also compared the anti-interference ability of three complexes in the detection of Xe.The experimental results show that the anti-interference ability of Tb^III-dtpa-AC in detecting Xe is stronger than that of Tb^III-dtpa-2A and Tb^III-dtpa-2C.Finally,all three complexes can be used to detect Xe in actual urine.Based on the experimental results,we propose the corresponding detection mechanism.