Rare earth complex and its preparation method and application

Abstract

The present invention relates to luminescent materials, and provides a rare earth complex and a preparation method and application thereof. The chemical formula of the rare earth complex is Ln2(2,4,5-TFBA)6(phen)2, wherein Ln represents a positive trivalent rare earth ion, 2,4,5-TFBA represents 2,4,5-trifluorobenzoic acid, and phen represents 1,10-o-phenanthroline. The rare earth complex is a highly sensitive fluorescent probe, which can be used as a fluorescent probe to detect fluoroquinolone drugs enrofloxacin (Enr) and ciprofloxacin (Cip) under the interference of different environmental factors, with the minimum detection limits of 0.15 nM and 0.1 nM, respectively.

Description

Technical Field

[0001] The invention relates to luminescent materials, and in particular to rare earth complexes and preparation methods and applications thereof. Background Art

[0002] Fluoroquinolones (FQS) are considered extremely important and high-priority antimicrobials and are frequently used in veterinary and human medicine. The persistence of these antibiotics and their poor metabolism have led to their detection in feces and aquatic environments. Thousands of tons of antimicrobials and their transformation products are released into the environment every year, which is a huge blow to the ecosystem and poses a huge threat to human health. The abuse of enrofloxacin (Enr) and ciprofloxacin (Cip) in animal husbandry and aquaculture and their illegal use during the egg-laying period have led to the enrichment of drugs in poultry eggs. Lack of monitoring will cause many harmful effects on human health. Therefore, there is an urgent need to explore ultra-sensitive and operational monitoring methods for rapid screening and quantitative monitoring of Enr and Cip in environmental waters, food and biological samples.

[0003] FQS detection uses a variety of technologies, such as electrochemical analysis, capillary electrophoresis, iodine titration, mass spectrometry (MS), inductively coupled plasma spectrometry (ICP-MS), gas chromatography (GC), etc., but they are usually slow, expensive, not suitable for field applications, have limited sensitivity and selectivity, or require technicians to collect, label and analyze samples. One of the beneficial spectral technologies is fluorescence sensing, which is commonly used to sense various chemicals, including metal ions, organic matter, biomolecules and cancer markers, without the need for complex sample preparation procedures. It is not only easy to operate and does not require special instruments, but also has high sensitivity, fast response and accurate sensing, overcoming the shortcomings of traditional methods, meeting the requirements of green chemical analysis, low cost, easy operation, high efficiency, sensitivity and selectivity, and providing an effective technology and application prospect for molecular detection.

[0004] Rare earth complex materials have become commonly used fluorescent probes in sensing applications because of their large Stokes shift, high quantum yield and obvious luminescence peak, narrow emission spectrum range, high energy conversion efficiency, flexible coordination mode, stable physical and chemical properties, high temperature resistance, ability to withstand high-power electron beams, high-energy radiation and strong ultraviolet light, long luminescence lifetime and excellent performance. Summary of the invention

[0005] Based on this, the present invention provides a rare earth complex, and uses its excellent fluorescence performance as a high-sensitivity fluorescent probe to detect enrofloxacin and ciprofloxacin in aqueous solution or actual samples.

[0006] In a first aspect, the present invention provides a rare earth complex, the chemical formula of which is Ln2(2,4,5-TFBA)6(phen)2, wherein Ln represents a trivalent rare earth ion, 2,4,5-TFBA represents 2,4,5-trifluorobenzoic acid, and phen represents 1,10-phenanthroline.

[0007] In a second aspect, the present invention provides a method for preparing the rare earth complex, the method comprising the following steps:

[0008] Dissolving a soluble trivalent rare earth salt in a first organic solvent to obtain a solution A;

[0009] Dissolve 2,4,5-trifluorobenzoic acid in water or a second organic solvent, and adjust the pH to 5-6 with an alkali solution to obtain a solution B;

[0010] Mixing the solution B with the solution A to obtain a mixed solution C;

[0011] Mixing 1,10-phenanthroline with the mixed solution C to obtain a mixed solution D;

[0012] The mixed solution D is reacted at 70° C. to 90° C. to obtain the rare earth complex.

[0013] In a third aspect, the present invention provides the use of the rare earth complex in the detection of enrofloxacin or ciprofloxacin.

[0014] In a fourth aspect, the present invention provides a test paper for detecting enrofloxacin or ciprofloxacin, wherein the test paper contains the rare earth complex.

[0015] The technical solution adopted in the embodiment of the present invention can at least achieve the following beneficial effects:

[0016] (1) A new rare earth co-doped complex Ln2(2,4,5-TFBA)6(phen)2 was prepared using 2,4,5-trifluorobenzoic acid and 1,10-phenanthroline as ligands and rare earth metals as central metals. 2,4,5-trifluorobenzoic acid was selected as the ligand because the three H atoms in the ligand molecule were replaced by F atoms, which reduced the oscillation effect in the solution and improved the energy transfer efficiency.

[0017] (2) The rare earth complex Ln2(2,4,5-TFBA)6(phen)2 can effectively and quickly detect Enr and Cip in water, pool water, lake water and egg white solution. It can be used for high-sensitivity detection of enrofloxacin and ciprofloxacin in actual samples. The detection range is 0-11 μM, and the LOD is as low as 0.15 nM and 0.1 nM, respectively, which is lower than the existing fluorescent probes on the market.

[0018] (3) Compared with conventional single-emission fluorescent probes, the rare earth complex Ln2(2,4,5-TFBA)6(phen)2 achieves strong anti-interference detection of enrofloxacin and ciprofloxacin in actual samples of tap water, lake water, pond water, and egg white. In addition, the signal changes can be easily distinguished by the naked eye under ultraviolet light. Therefore, it is made into an easy-to-use test paper sensor device that can be used for on-site rapid detection of enrofloxacin and ciprofloxacin in sample solutions;

[0019] (4) The synthesis process of the rare earth complex Ln2(2,4,5-TFBA)6(phen)2 is simple, low-cost, highly efficient, and reproducible. It can be applied to industrial production and has potential application prospects in the fields of environmental monitoring and food science. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the infrared spectra of rare earth complex materials Tb2, Gd2, Tb2-1, Tb2-2 and ligands.

[0021] Figure 2 Schematic diagram of the basic structural unit of the rare earth complex Ln2(2,4,5-TFBA)6(phen)2.

[0022] Figure 3 Schematic diagram of the 3D stacking of the basic structural unit of the rare earth complex Ln2(2,4,5-TFBA)6(phen)2.

[0023] Figure 4 This is the PXRD pattern of the rare earth complex material (Tb2) that was immersed in different pH and solvents for a period of time and then centrifugally dried.

[0024] Figure 5 These are the PXRD patterns of Tb2 before and after the reaction with enrofloxacin and ciprofloxacin.

[0025] Figure 6 The excitation and emission fluorescence spectra of Tb2.

[0026] Figure 7 This is a bar graph of the rare earth complex material (Tb2) mixed with 75 different substances in a deionized water environment (excitation wavelength is 290 nm, and the highest characteristic peak is 534 nm).

[0027] Figure 8 This is the anti-interference result diagram of the reaction between rare earth complex material (Tb2) and enrofloxacin.

[0028] Fig. 9 This is the anti-interference result diagram of the reaction between rare earth complex material (Tb2) and ciprofloxacin.

[0029] Fig.10This is the time response diagram of the rare earth complex material (Tb2) to enrofloxacin.

[0030] Fig.11 This is the time response diagram of the rare earth complex material (Tb2) to ciprofloxacin.

[0031] Fig.12 The figure is a concentration-dependence curve in the short linear range obtained by plotting the enrofloxacin concentration as the abscissa and the fluorescence intensity at 535 nm as the ordinate.

[0032] Fig.13 The concentration dependence curve in the short linear range was obtained by plotting the ciprofloxacin concentration as the abscissa and the fluorescence intensity at 535 nm as the ordinate.

[0033] Fig.14 The figure is a concentration-dependence curve in the long linear range obtained by plotting the enrofloxacin concentration as the abscissa and the fluorescence intensity at 535 nm as the ordinate.

[0034] Fig.15 The concentration dependence curve in the long linear range was obtained by plotting the ciprofloxacin concentration as the abscissa and the fluorescence intensity at 535 nm as the ordinate.

[0035] Fig.16 This is the detection limit spectrum of rare earth complex material (Tb2) for enrofloxacin.

[0036] Fig.17 This is the detection limit spectrum of rare earth complex material (Tb2) for ciprofloxacin.

[0037] Fig.18 The spectra of the reaction of Tb2 with enrofloxacin and ciprofloxacin in tap water, lake water, pond water and pure natural egg white are shown in the figure, and the inset is the corresponding luminescence histogram.

[0038] Fig.19 This is an ultraviolet photograph obtained after adding solutions of 75 different substances to a test paper made of rare earth complex material (Tb2). DETAILED DESCRIPTION

[0039] Some embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings to fully illustrate the purpose, scheme and effect of the present invention.

[0040] The invention provides a rare earth complex, wherein the chemical molecular formula of the rare earth complex is Ln2(2,4,5-TFBA)6(phen)2, wherein Ln represents a positive trivalent rare earth ion, 2,4,5-TFBA represents 2,4,5-trifluorobenzoic acid, and phen represents 1,10-phenanthroline.

[0041] In some preferred embodiments, the trivalent rare earth ion is Tb 3+ or Gd 3+ .

[0042] In some preferred embodiments, the rare earth complex crystallizes in the triclinic system with a space group of P- 1. Unit cell parameters: a = 9.83740(10) ~ 9.84000(10) Å, b = 12.3628(2) ~ 12.3662(2) Å, c = 12.6447(2)~ 12.6518(2) Å, α = 83.021(2) ~ 83.0490(10)°, β =87.1240(10) ~ 87.1370(10)°, γ =73.1840(10) ~73.1860°, V = 1461.79(4) ~1461.87(4) Å 3 .

[0043] The rare earth complex can be used as a basic structural unit and can be stacked in sequence through van der Waals forces and π-π stacking interactions to form a rare earth complex crystal material; the rare earth complex crystal material can be represented by a chemical molecular formula [Ln2(2,4,5-TFBA)6(phen)2]n, wherein Ln represents a trivalent rare earth ion, 2,4,5-TFBA represents 2,4,5-trifluorobenzoic acid, phen represents 1,10-phenanthroline, and n represents a positive integer. The basic structural unit is a neutral structural unit composed of two crystallographically independent Ln, six 2,4,5-TFBA ligands and two 1,10-phenanthroline. There are van der Waals forces and weak π-π stacking interactions between the coordinated ligand molecules in the two basic structural units. There are six fully coordinated oxygens in the six 2,4,5-BTDB ligands. Ln adopts an eight-coordination mode, and the 2,4,5-BTDB ligands and Ln adopt two coordination modes: bridging and chelating. The bond length of Tb-O is between 2.2981 (17) and 2.4445 (17) Å, and the bond length of Tb-N is between 2.541 (2) and 2.588 (2) Å.

[0044] The method for preparing the rare earth complex comprises the following steps:

[0045] (a) dissolving a soluble trivalent rare earth salt in a first organic solvent to obtain a solution A;

[0046] (b) dissolving 2,4,5-trifluorobenzoic acid in water or a second organic solvent, and adjusting the pH to 5-6 with an alkali solution to obtain a solution B;

[0047] (c) mixing the solution B with the solution A to obtain a mixed solution C;

[0048] (d) mixing 1,10-phenanthroline with the mixed solution C to obtain a mixed solution D;

[0049] (e) reacting the mixed solution D at 70° C. to 90° C. to obtain the rare earth complex.

[0050] In some preferred embodiments, the soluble trivalent rare earth salt is any one of nitrate, chloride, acetate, sulfonate, oxalate, and trifluoromethanesulfonate of terbium or gadolinium.

[0051] In some preferred embodiments, the first organic solvent is one or a combination of two or more of dimethyl sulfoxide, dimethylacetamide, N,N-dimethylformamide, methanol, acetone, tetrahydrofuran, ethanol, acetonitrile, dichloromethane, and chloroform; the second organic solvent is one or a combination of two or more of dimethyl sulfoxide, dimethylacetamide, N,N-dimethylformamide, methanol, acetone, tetrahydrofuran, ethanol, and acetonitrile.

[0052] In some preferred embodiments, the alkali solution is one or a combination of two or more of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, triethylamine aqueous solution, and ammonia water.

[0053] In some preferred embodiments, the reaction time of step (e) is 2 to 6 days, and the reaction conditions are any one of normal pressure, nitrogen, oxygen and argon atmosphere.

[0054] The rare earth complex can be used as a fluorescent probe for quantitative detection of the content of enrofloxacin and ciprofloxacin in aqueous solutions or actual samples. For example, the rare earth complex is dissolved and then soaked in filter paper, and the soaked filter paper is dried to obtain a test paper for detecting enrofloxacin or ciprofloxacin, and the test paper can be used for qualitative detection of enrofloxacin and ciprofloxacin.

[0055] Some typical embodiments are described below.

[0056] Example 1

[0057] A rare earth complex material (Tb2), the preparation method of which comprises the following steps:

[0058] (a) Dissolve 10.4 mg of terbium nitrate hexahydrate in 1.0 mL of dimethyl sulfoxide to obtain rare earth salt solution A;

[0059] (b) 16.2 mg of 2,4,5-trifluorobenzoic acid was placed in a beaker, 1.0 mL of water was added, and then the pH of the 2,4,5-trifluorobenzoic acid solution was adjusted to 5.0 with 0.1 M sodium hydroxide solution to obtain a deprotonated 2,4,5-trifluorobenzoic acid solution B;

[0060] (c) slowly adding the 2,4,5-trifluorobenzoic acid solution B obtained in step (b) to the rare earth salt solution A obtained in step (a), mixing well, and obtaining a mixed solution C;

[0061] (d) 4.6 mg of 1,10-phenanthroline was placed in a 10.0 mL flask, and the mixed solution C obtained in step (c) was added and mixed evenly to obtain a mixed solution D;

[0062] (e) The obtained mixed solution D was placed in a 10.0 mL small flask and reacted at 80°C for 3 days to obtain 3.3 g of colorless block crystals, i.e., rare earth complex material, recorded as Tb2. The X-ray single crystal diffraction and Fourier transform infrared spectroscopy tests were performed on the obtained mixture. The test results are shown in Tables 1 and Figure 1 shown.

[0063] Example 2

[0064] A rare earth complex material (Gd2), the preparation method of which comprises the following steps:

[0065] (a) Dissolve 10.4 mg of nitric acid hexahydrate in 1.0 mL of dimethyl sulfoxide to obtain rare earth salt solution A;

[0066] (b) 16.2 mg of 2,4,5-trifluorobenzoic acid was placed in a beaker, 1.0 mL of water was added, and then the pH of the 2,4,5-trifluorobenzoic acid solution was adjusted to 5.0 with 0.1 M sodium hydroxide solution to obtain a deprotonated 2,4,5-trifluorobenzoic acid solution B;

[0067] (c) slowly adding the 2,4,5-trifluorobenzoic acid solution B obtained in step (b) to the rare earth salt solution A obtained in step (a), mixing well, and obtaining a mixed solution C;

[0068] (d) 4.6 mg of 1,10-phenanthroline was placed in a 10.0 mL flask, and the mixed solution C obtained in step (c) was added and mixed evenly to obtain a mixed solution D;

[0069] (e) The obtained mixed solution D was placed in a 10.0 mL small flask and reacted at 80°C for 3 days to obtain 3.5 g of colorless block crystals, i.e., rare earth complex material, denoted as Gd2. The X-ray single crystal diffraction and Fourier transform infrared spectroscopy tests were performed on the obtained mixture. The test results are shown in Tables 1 and Figure 1 shown.

[0070] Example 3

[0071] A rare earth complex material (Tb2-1), wherein the preparation method thereof is as follows: only the step (a) of Example 1 in which "terbium nitrate hexahydrate is dissolved in 1.0 mL of dimethyl sulfoxide" is adjusted to "terbium chloride hexahydrate is dissolved in 4.0 mL of acetonitrile", and the other steps are the same as those of Example 1, to obtain 2.9 mg of colorless block crystals, recorded as Tb2-1, and the same is tested by single crystal X-ray diffraction and Fourier transform infrared spectroscopy. The test results are shown in Tables 1 and Figure 1 shown.

[0072] Example 4

[0073] A rare earth complex material (Tb2-2), the preparation method of which is to adjust "terbium nitrate hexahydrate dissolved in 1.0 mL of dimethyl sulfoxide" in step (a) of Example 1 to "terbium chloride hexahydrate dissolved in 4.0 mL of acetonitrile", and to adjust "reacting at 80°C for 3 days" in step (e) to "reacting at 75°C for 3 days", and the other steps are the same as in Example 1, to obtain 3.2 mg of colorless block crystals, recorded as Tb2-2, and to perform X-ray single crystal diffraction and Fourier transform infrared spectroscopy tests on the same. The test results are shown in Tables 1 and Figure 1 shown.

[0074] The inventors also conducted relevant tests on the rare earth complex material (Tb2) prepared in Example 1.

[0075] Example 5

[0076] The stability test of rare earth complex materials specifically includes the following steps:

[0077] Tb2 powder was placed or soaked in enrofloxacin solution, ciprofloxacin solution, aqueous solutions of different pH values, and nine organic solvents (methanol, ethanol, acetonitrile, acetone, tetrahydrofuran, etc.) for a period of time, centrifuged and dried, and then subjected to PXRD test. The test results are as follows: Figure 4 and Figure 5 shown.

[0078] Depend on Figure 4 and Figure 5 It can be seen that the test results of PXRD are basically consistent with the crystal simulation peak, which shows that the rare earth complex material prepared by the present invention has excellent stability.

[0079] Example 6

[0080] The research on the fluorescence properties of rare earth complex (Tb2) materials specifically includes the following steps:

[0081] In order to study the photophysical properties of Tb2, their excitation and emission spectra were measured at room temperature, such as Figure 6 As shown. Prepare Tb2 powder into 10 -3 mol / L DMF solution, take 50 μL of Tb2 DMF solution and add it to 4.9 mL deionized water, and divide it into 76 portions. Add 50 μL of deionized water to one portion as a blank sample, and then add 50 μL of enrofloxacin and ciprofloxacin solutions (1.0×10 −3 M) (solvent is DMF), and finally, enrofloxacin and ciprofloxacin solutions (1.0×10 −3 M) and 73 other substances with equal concentrations [24 solvents: CH3CH2OH (EtOH), acetonitrile(EtCN), CH3OH (MeOH), acetylacetone (Acac), acetone, N,N-dimethylformamide(DMF), dichloromethane (Dcm), isopropyl alcohol (Ipa), tetrahydrofuran (THF),benzene (C6H6), 1,3-propanediol (1,3-Pdo), tert-butyl alcohol (Tba),methylbenzene (C7H8), phenylamine(C6H7N), butyl alcohol (1-BuOH), ether,pyridine, propyl alcohol (Pro-OH), dimethylacetamide (DMA), dimethylsulfoxide (DMSO), ethylene glycol (Eg), trichloromethane (Tcm), 2-butanol(C4H 10 O), glycerine; 15 cations: Fe 2+ , Fe 3+ , Ca 2+ , Ba 2+ , Cu 2+ , Cd 2+ ,Zn 2+ , Pb 2+ , Mg 2+ ,NH4 + , Ni 2+ , Mn 2+ , Co 3+ , Cr 3+ , K+ ;11 anions: SO3 2- , SO4 2- , C6H6O7 2- , C6H5CO2 - ,CH3COO - , [B(C6H5)4] - , B4O7 2- , C7H7SO3 - , AlO2 - , WO4 2- , SiO3 2- ; 7 amino acids: L-threonine (L-thr), L-methionine (L-met), L-lysine (L-lys), L-valine (L-val), L-tryptophan (L-try), L-leucine (L-leu), L-phenylalanine (L-phe); 6 substances that may be present in urine: Urea, kynuramine (Kyn), glucose (Glu), creatine (Cr), creatinine (Cre), methyl glycosine (Met); 4 pesticides: chlorpyrifos, isoprocarb, acephate, bassa; 4 tumor markers: L-kynurenine (L-kyn), 4-hydroxybenzoic acid (4-Hyd), 5-hydroxyindole-3-acetic acid (5-Hiaa), hippuric acid (Hip); 2 floxacin substances: ofloxacin (Ofx), levofloxacin (Lvx)], under the same conditions, the fluorescence performance test (excitation wavelength is 290 nm), the test results are as follows Figure 7 shown.

[0082] Example 7

[0083] The anti-interference test of rare earth complex materials specifically includes the following steps:

[0084] In order to investigate whether the detection of enrofloxacin and ciprofloxacin has good anti-interference ability, a competition experiment was conducted. 4.4 mL of deionized water and 50 μL of Tb2 solution (1.0×10 -3 M, DMF), 50 μL of enrofloxacin and ciprofloxacin solution (1.0×10 -3M) and 500 μL competitor (1.0×10 -3 The above method was used to determine the luminescence characteristics of Tb2 reacting with enrofloxacin and ciprofloxacin in the presence of 74 competing substances ( Figure 8 , Fig. 9 ). The results showed that Tb2 still showed obvious luminescence enhancement for enrofloxacin and ciprofloxacin in the presence of 10 equivalents of anti-interference substances, indicating that the sensor has high anti-interference ability.

[0085] Example 8

[0086] The response time and concentration dependence test of rare earth complexes specifically includes the following steps:

[0087] The response time of Tb2 to enrofloxacin and ciprofloxacin was also monitored by monitoring the luminescence intensity at 535 nm. Fig.10 , Fig.11 It can be seen that Tb2 can achieve a rapid response to enrofloxacin or ciprofloxacin within 15 seconds, and the sensing signal is stable within 1.0 hour, indicating that Tb2 is a highly stable sensor. In order to further understand the sensing properties of Tb2, the relationship between the luminescence intensity of Tb2 and the concentrations of enrofloxacin and ciprofloxacin was studied. In the range of 0~1.6 nm, the luminescence intensity (at 535nm) and the concentration of enrofloxacin (at 1.6 nm) are closely related. Fig.12 ) and ciprofloxacin ( Fig.13 ) concentrations showed a good linear relationship; in the wide concentration range of 0~11 μM, the luminescence intensity (at 535 nm) was significantly higher than that of enrofloxacin ( Fig.14 ) and ciprofloxacin ( Fig.15 ) concentrations still showed a good linear relationship.

[0088] Example 9

[0089] The feasibility test of rare earth complex sensing in actual samples includes the following steps:

[0090] The detection limits of rare earth complex materials as fluorescent probes for enrofloxacin and ciprofloxacin are as low as 0.15nM and 0.1nM, respectively. Fig.16 and Fig.17 As shown in the figure, its LOD value is lower than the national standard (GB 31650-2019, ≤1.0μg / kg egg, 2.53 nM Enr Cip and 2.75 nM), indicating that Tb2 is a highly sensitive detector for enrofloxacin and ciprofloxacin. Therefore, whether Tb2 can be used as a luminescent probe for the detection of enrofloxacin and ciprofloxacin in actual samples of pure natural egg white, tap water, lake water and pond water was also investigated. 4.9 mL of pure natural egg white preparation, tap water, lake water or pond water were mixed with 50 μL Tb2 solution (1.0×10 -3M, DMF) and 50 μL 1.0×10 -3 M enrofloxacin and ciprofloxacin were mixed. The results showed that Tb2 could still react sensitively with enrofloxacin and ciprofloxacin in pure natural egg white, tap water, lake water and pond water, and the luminescence was still significantly enhanced ( Fig.18 ), confirming the application potential of Tb2 in the detection of enrofloxacin and ciprofloxacin in real samples of pure natural egg white, tap water, lake water and pond water.

[0091] Example 10

[0092] The test paper prepared by using the rare earth complex is used for the detection of enrofloxacin and ciprofloxacin, which specifically comprises the following steps:

[0093] Cut the filter paper into appropriate size (1*1 cm 2 ), soaked in Tb2 (0.01 M) DMF solution for 25 minutes, and then dried at 60 ° C for sensing applications. The above 75 different substance solutions were added to the above dry test paper, and the blank was used as a control. After drying, they were placed neatly and photographed under 365 nm ultraviolet light. The obtained photos are shown in the figure. Fig.19 As shown. Fig.19 It can be seen that except for the test paper with enrofloxacin and ciprofloxacin solution added, the test paper has a unique Tb 3+ The green luminescence is significantly enhanced, indicating that the rare earth complex material prepared by the present invention can be made into test paper for the qualitative detection of enrofloxacin and ciprofloxacin.

[0094] Table 1 Crystallographic data of Tb2 and Gd2

[0095]

[0096] The above is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiment. Embodiments that achieve the same or equivalent technical effects by the same or equivalent means should all fall within the protection scope of the present invention.

Claims

1. Application of a rare earth complex in the detection of enrofloxacin or ciprofloxacin, characterized in that: The chemical formula of the rare earth complex is Ln2(2,4,5-TFBA)6(phen)2, wherein Ln represents a positive trivalent rare earth ion, 2,4,5-TFBA represents 2,4,5-trifluorobenzoic acid, and phen represents 1,10-o-phenanthroline; the positive trivalent rare earth ion is Tb 3+ .

2. The use according to claim 1, characterized in that: The rare earth complex crystallizes in the triclinic system, and the space group is P- 1. Unit cell parameters: a = 9.83740(10) ~ 9.84000(10) Å, b = 12.3628(2) ~ 12.3662(2)Å, c = 12.6447(2) ~ 12.6518(2) Å, α = 83.021(2) ~ 83.0490(10)°, β =87.1240(10) ~ 87.1370(10)°, c = 73.1840(10) ~73.1860°, V = 1461.79(4) ~1461.87(4)Å 3 .

3. A test paper for detecting enrofloxacin or ciprofloxacin, characterized in that: Contains a rare earth complex; the chemical formula of the rare earth complex is Ln2(2,4,5-TFBA)6(phen)2, wherein Ln represents a positive trivalent rare earth ion, 2,4,5-TFBA represents 2,4,5-trifluorobenzoic acid, and phen represents 1,10-o-phenanthroline; the positive trivalent rare earth ion is Tb 3+ .

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