Ratio fluorescent probe CQDs (at) Eu-UiO-66 with high selectivity to Hg < 2 + > and NOR as well as preparation method and application of ratiometric fluorescent probe CQDs (at) Eu-UiO-66
CQDs@Eu-UiO-66 composite material was synthesized by solvothermal method. Combined with a UV cassette integrated into a smartphone, it enables rapid and accurate detection of Hg2+ and NOR. This solves the problems of low efficiency, time consumption and poor portability of traditional detection methods, and realizes high sensitivity and portability for water environment detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HENAN UNIV OF CHINESE MEDICINE
- Filing Date
- 2026-03-16
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies are insufficient for the rapid and accurate detection of Hg2+ and NOR in aquatic environments, and traditional methods rely on large instruments, have complex pretreatment processes, and are not portable.
CQDs@Eu-UiO-66 composite material was synthesized using a solvothermal method. Visual quantitative detection of ratio fluorescence probes was achieved through a UV dark box integrated into a smartphone. The high selectivity of CQDs@Eu-UiO-66 to Hg2+ and NOR was utilized, and rapid detection was performed by combining the RGB value ratio.
It enables the detection of trace or ultra-trace amounts of Hg2+ and NOR, with detection limits as low as 2.08 nM and 48.96 nM, respectively. It has high sensitivity and good thermal stability, making it suitable for large-scale industrial production.
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Figure CN122011420A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of metal-organic framework materials, and particularly relates to a method for treating Hg. 2+ The ratiometric fluorescent probe CQDs@Eu-UiO-66 with high selectivity to NOR, its preparation method, and its application in dual-mode colorimetric detection. Background Technology
[0002] The problem of complex pollution in the aquatic environment is becoming increasingly serious, especially the coexistence of heavy metals and antibiotics, making the development of efficient and sensitive pollutant detection technologies a current research hotspot in the field of environmental monitoring. Mercury ions (Hg) 2+ As a typical toxic heavy metal pollutant, Hg exhibits strong mobility and bioaccumulation. 2+ It can be converted into more toxic organic mercury, which enters the human body through the food chain, causing damage to the nervous, renal, and immune systems, and increasing the risk of cardiovascular disease and developmental abnormalities. Meanwhile, norfloxacin (NOR), a typical representative of fluoroquinolone antibiotics, is widely used in human medicine and aquaculture. Its chemical structure is stable and difficult to completely degrade in the natural environment. Long-term residues can easily induce microorganisms to develop drug-resistant genes, disrupt the aquatic ecological balance, and may indirectly affect human health through drinking water or the food chain.
[0003] Traditional heavy metal detection methods, such as inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), high-performance liquid chromatography (HPLC), atomic absorption spectrometry (AAS), and atomic fluorescence spectrometry (AFS), while highly accurate, typically rely on large instruments, involve complex pretreatment processes, and are difficult to implement for rapid on-site detection. In recent years, fluorescence sensing technology has attracted widespread attention due to its advantages of low cost, fast response, and high sensitivity. Carbon quantum dots, as a novel fluorescent nanomaterial, are characterized by abundant raw materials and simple preparation; metal-organic frameworks, on the other hand, have become a research hotspot due to their tunable pore structure and high specific surface area. For Hg... 2+ Given the cumulative, migratory, and recalcitrant properties of NOR, developing fluorescent probe materials capable of rapid and accurate detection is of great significance for objectively assessing the status of complex pollution and ensuring the safety of the water environment. Summary of the Invention
[0004] The purpose of this invention is to provide a method for treating Hg. 2+ The ratiometric fluorescent probe CQDs@Eu-UiO-66 with high selectivity to NOR, along with its preparation method and application, effectively solves the problems of low efficiency, time consumption, susceptibility to interference, and poor portability of traditional testing methods.
[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A type of Hg 2+ The preparation method of CQDs@Eu-UiO-66, a ratiometric fluorescent probe with high selectivity to NOR, includes the following steps: CQDs, EuCl3·6H2O, ZrCl4, and BDC are ultrasonically dissolved in DMF, transferred to a reaction vessel for solvothermal synthesis, and after centrifugation, purification, and vacuum drying for 24 hours, the CQDs@Eu-UiO-66 composite material is obtained.
[0006] Furthermore, the reaction temperature is 120 °C, the reaction time is 24 hours, and the amount of carbon quantum dots added is 2-10 mg.
[0007] Furthermore, the molar ratio of EuCl3·6H2O, ZrCl4, and BDC is 1:9:10.
[0008] Using Hg 2+ The probe, prepared using a method for fabricating highly selective ratiometric fluorescent probes CQDs@Eu-UiO-66 with NOR, overcomes the aggregation quenching phenomenon of carbon quantum dots and exhibits excellent fluorescence properties, high specific surface area, and good thermal stability. Simultaneously, the composite probe shows resistance to Hg. 2+ Both NOR and other compounds exhibit significant specificity recognition capabilities, demonstrating good application potential.
[0009] This probe is used for trace or ultra-trace detection of Hg. 2+ Ions, which are related to Hg in aqueous solution 2+ The detection limit is as low as 2.08 nM.
[0010] This probe is used for trace or ultra-trace detection of NOR, with a detection limit as low as 48.96 nM for NOR in aqueous solution.
[0011] Application: This invention integrates CQDs@Eu-UiO-66 and a UV dark box into a smartphone to detect Hg in real time using a visual quantitative method. 2+ And NOR. Using color-picking software (Color Picker Application) installed on a smartphone, probes detect different concentrations of Hg. 2+ The fluorescence color signal under NOR conditions is converted to RGB values, and the ratio of the sum of red (R) and green (G) values to the blue (B) value is used as Hg. 2+ And NOR detection is an effective indicator that can achieve Hg 2+ Fast, visual, and intelligent detection of NOR.
[0012] The advantages of this invention are: the ratiometric fluorescent probe CQDs@Eu-UiO-66 metal-organic framework material of this invention is effective against Hg. 2+Both NOR and this probe exhibit selective fluorescence detection capabilities, high sensitivity, and good stability. Furthermore, the probe is synthesized via a solvothermal method, which is simple to operate and suitable for large-scale industrial production, making it highly valuable for research and application. Attached Figure Description
[0013] Figure 1 This is a comparison of nitrogen adsorption-desorption isotherms of the ratiometric fluorescent probes prepared in Examples 1-3 of this invention at 77 K.
[0014] Figure 2 This is a comparison of the infrared spectra (4000 cm⁻¹) of the ratiometric fluorescent probes prepared in Examples 1-3 of this invention and the original Eu-UiO-66. -1 -400 cm -1 ).
[0015] Figure 3 This is a comparison of the infrared spectra (4000 cm⁻¹) of the ratiometric fluorescent probes prepared in Examples 1-3 of this invention and the synthesized materials. -1 -400 cm -1 ).
[0016] Figure 4 This is the full X-ray photoelectron spectrum of the ratiometric fluorescent probe prepared in Example 1 of this invention.
[0017] Figure 5 This is a fine X-ray photoelectron spectrum of the ratiometric fluorescent probe prepared in Example 1 of the present invention with respect to C1s.
[0018] Figure 6 This is a fine X-ray photoelectron spectrum of the ratiometric fluorescent probe prepared in Example 1 of the present invention with respect to O1s.
[0019] Figure 7 This is a fine X-ray photoelectron spectrum of the ratiometric fluorescent probe prepared in Example 1 of the present invention with respect to Zr 3d.
[0020] Figure 8 This is a fine X-ray photoelectron spectrum of the ratiometric fluorescent probe prepared in Example 1 of this invention with respect to Eu3d.
[0021] Figure 9 This is a comparison chart of the thermal stability of the ratiometric fluorescent probes prepared in Examples 1-3 of this invention and the original Eu-UiO-66.
[0022] Figure 10 This is a fluorescence intensity diagram of the ratiometric fluorescent probe prepared in Example 1 of the present invention after fluorescence sensing of different metal ions.
[0023] Figure 11This is a fluorescence intensity diagram of the ratiometric fluorescent probe prepared in Example 1 of the present invention after fluorescence sensing of different antibiotics.
[0024] Figure 12 The ratiometric fluorescent probe prepared in Example 1 of this invention is used to sense different concentrations of Hg. 2+ Fluorescence emission spectrum after ionization.
[0025] Figure 13 The ratiometric fluorescent probe prepared in Example 1 of this invention is used in low-concentration fluorescent sensing of Hg. 2+ Linear fitting plot of ions.
[0026] Figure 14 This is the fluorescence emission spectrum of the ratiometric fluorescent probe prepared in Example 1 of the present invention after sensing different concentrations of NOR.
[0027] Figure 15 This is a linear fitting graph of the ratiometric fluorescent probe prepared in Example 1 of the present invention at a low concentration of fluorescent sensing NOR.
[0028] Figure 16 The ratiometric fluorescent probe prepared in Example 1 of this invention is used for Hg 2+ A schematic diagram of a smartphone integrated sensing platform for rapid NOR detection.
[0029] Figure 17 The ratiometric fluorescence detector for Hg detection prepared in Example 1 of this invention 2+ Linear fitting plot of RGB values and concentration.
[0030] Figure 18 This is a linear fit graph between the RGB values and concentration of the ratiometric fluorescence detector prepared in Example 1 of this invention when detecting NOR. Detailed Implementation
[0031] Example 1 2.00 mg CQDs, 36.64 mg europium trichloride hexahydrate (EuCl3·6H2O, 0.122 mmol / L), 255.86 mg zirconium tetrachloride (ZrCl4, 1.098 mmol / L), and 202.68 mg terephthalic acid (BDC, 1.22 mmol / L) were dissolved in 50 mL DMF, sonicated, and transferred to a 100 mL polytetrafluoroethylene-lined reactor. The reactor was sealed and placed in a constant-temperature drying oven. The temperature was increased from room temperature to 120 °C over 30 min, and the reaction was carried out at 120 °C for 24 h. After the reaction, the reactor was allowed to cool naturally to room temperature, and the product was then centrifuged and purified. The purification process mainly involved soaking the product three times in DMF and ethanol, each time for 24 h, while ensuring it was sealed and protected from light. Finally, the product was vacuum dried in an 80 °C vacuum drying oven for 24 h to obtain the final product, denoted as CQDs-1@Eu-UiO-66.
[0032] Example 2 6.00 mg CQDs, 36.64 mg europium trichloride hexahydrate (EuCl3·6H2O, 0.122 mmol / L), 255.86 mg zirconium tetrachloride (ZrCl4, 1.098 mmol / L), and 202.68 mg terephthalic acid (BDC, 1.22 mmol / L) were dissolved in 50 mL DMF, sonicated, and transferred to a 100 mL polytetrafluoroethylene-lined reactor. The reactor was sealed and placed in a constant-temperature drying oven. The temperature was increased from room temperature to 120 °C over 30 min, and the reaction was carried out at 120 °C for 24 h. After the reaction, the reactor was allowed to cool naturally to room temperature, and then the product was centrifuged and purified. The purification process mainly involved soaking the product three times in DMF and ethanol, each time for 24 h, while ensuring it was sealed and protected from light. Finally, the product was vacuum dried in an 80 °C vacuum drying oven for 24 h to obtain the final product, denoted as CQDs-2@Eu-UiO-66.
[0033] Example 3 10.00 mg CQDs, 36.64 mg europium trichloride hexahydrate (EuCl3·6H2O, 0.122 mmol / L), 255.86 mg zirconium tetrachloride (ZrCl4, 1.098 mmol / L), and 202.68 mg terephthalic acid (BDC, 1.22 mmol / L) were dissolved in 50 mL DMF, sonicated, and transferred to a 100 mL polytetrafluoroethylene-lined reactor. The reactor was sealed and placed in a constant-temperature drying oven. The temperature was increased from room temperature to 120 °C over 30 min, and the reaction was carried out at 120 °C for 24 h. After the reaction, the reactor was allowed to cool naturally to room temperature, and then the product was centrifuged and purified. The purification process mainly involved soaking the product three times in DMF and ethanol, each time for 24 h, while ensuring it was sealed and protected from light. Finally, the product was vacuum dried in an 80 °C vacuum drying oven for 24 h to obtain the final product. It is denoted as CQDs-3@Eu-UiO-66.
[0034] Performance testing: (I) N2 adsorption-desorption analysis Nitrogen adsorption-desorption tests were performed on the synthesized Eu-UiO-66 and the ratiometric fluorescent probes synthesized in Examples 1-3 at 77 K. The specific surface area, micropore volume, total pore volume, and average pore size results are shown in Table 1.
[0035] Table 1 Pore structure parameters of Eu-UiO-66 and CQDs-@Eu-UiO-66 with different proportions Depend on Figure 1 It was observed that under relatively low pressure (P / P0), the N2 adsorption capacity of both Eu-UiO-66 and CQDs@Eu-UiO-66 materials increased rapidly. After reaching a certain relative pressure, adsorption saturation occurred, conforming to a typical type I isotherm, indicating the presence of numerous microporous structures in the CQDs@Eu-UiO-66 material. Calculations using the Brunauer-Emmett-Teller (BET) and Langmuir models suggested that the decrease in specific surface area might be due to CQDs blocking the pores of the CQDs@Eu-UiO-66 composite material, leading to a reduction in micropore volume and pore diameter. Considering specific surface area, micropore volume, and other pore structure parameters, the ratio fluorescent probe CQDs-1@Eu-UiO-66, which has the largest specific surface area and total pore volume, was selected as the optimal material and applied to subsequent fluorescence sensing experiments.
[0036] (ii) Infrared spectroscopy analysis Figure 2 , 3The infrared spectra of Eu-UiO-66 and CQDs@Eu-UiO-66 are shown. The figures reveal that the infrared characteristic peaks of CQDs@Eu-UiO-66 with different proportions remain unchanged, proving that the introduction of CQDs does not affect the structure of Eu-UiO-66. The 673 cm⁻¹ peak is also shown. -1 The characteristic peak at that location is due to the O atoms and Zr atoms in BDC. 4+ Zr-O bonds are formed in the middle. 1397 cm -1 The characteristic peak at 1579 cm⁻¹ represents the stretching vibration of CO. -1 The characteristic peak at this location represents the symmetric and asymmetric stretching vibrations of -COO in the metal-organic framework. It is located at approximately 3500 cm⁻¹. -1 The characteristic peaks are due to the symmetric and asymmetric stretching vibrations of OH and NH induced by BDC and CQDs. FT-IR results confirmed the successful synthesis of CQDs@Eu-UiO-66.
[0037] (III) XPS Analysis To further analyze the structure of the composite material, the surface elemental composition and chemical state of CQDs@Eu-UiO-66 were characterized by XPS. Distinct diffraction peaks at 1124.83, 531.76, 401.08, 284.80, and 182.79 eV were found in the full XPS spectrum of CQDs@Eu-UiO-66, belonging to Eu 3d, O 1s, N 1s, C 1s, and Zr 3d, respectively. Figure 4 In the high-resolution C 1s spectrum, the presence of CC / CH / C=C (284.80 eV), CN (286.51 eV), and -OC=O (288.74 eV) indicates that element C exists in the composite material. 2 and sp 3 This proves the formation of carbon quantum dots ( Figure 5 In the O 1s high-resolution spectrum, three peaks were observed at 530.31, 531.76, and 532.94 eV, corresponding to the O-Eu, -OC=O, and O-OH / COC bonds, respectively. Figure 6 The distinct double peaks at 182.79 and 185.17 eV observed in the high-resolution Zr3d spectrum are characteristic of Zr. 4+ Zr 3d ions 3 / 2 and Zr 3d 5 / 2 ( Figure 7 In the high-resolution energy spectrum of Eu 3d, the spin-orbit interaction of Eu produces four characteristic peaks at 1164.88, 1155.73, 1134.77, and 1124.83 eV, corresponding to Eu 3d eV and 1124.83 eV respectively. 3+ 3D 3 / 2 Eu 2+3D 3 / 2 Eu 3+ 3D 5 / 2 and Eu 2+ 3D 5 / 2 energy spectrum peaks ( Figure 8 Furthermore, the increased binding energy of Eu 3d in CQDs@Eu-UiO-66 indicates an interaction between CQDs and Eu, consistent with the results of Fourier transform infrared spectroscopy, confirming the successful synthesis of CQDs@Eu-UiO-66.
[0038] (iv) Thermal stability analysis Figure 9 The figures show the thermal stability analysis of Eu-UiO-66 and the ratiometric fluorescent probe CQDs@Eu-UiO-66. It can be seen that the weight loss of Eu-UiO-66 and CQDs@Eu-UiO-66 mainly occurs in three stages. The first stage of weight reduction is primarily due to the loss of water and DMF molecules. The second stage occurs in the 250-500℃ range, mainly due to the decomposition of CQDs and the partial dissociation of organic ligands in CQDs@Eu-UiO-66. The third stage, a significant weight reduction, is mainly due to the mass loss caused by the collapse of the MOF framework. The disintegration temperatures of the CQDs@Eu-UiO-66 series after carbon quantum doping are slightly higher than those of Eu-UiO-66, indicating that the modified CQDs@Eu-UiO-66 has better thermal stability than Eu-UiO-66.
[0039] (v) Fluorescence Selectivity Analysis Investigating the effects of ratiometric fluorescent probes CQDs@Eu-UiO-66 on different Ag metal ions + Al 3+ As 5+ Ba 2+ Cd 2+ Cr 3+ Pb 2+ Cu 2+ Mn 4+ and Hg 2+ fluorescence sensing performance such as Figure 10 As shown. The fluorescence sensing performance of the fluorescent probe CQDs@Eu-UiO-66 for different antibiotics, sulfadiazine (SD), norfloxacin (NOR), penicillin (PG), and erythromycin (EM), was also investigated. Figure 11 As shown. By Figure 10 It can be seen that, compared with other heavy metal ions, CQDs@Eu-UiO-66 has a greater effect on Hg. 2+ It exhibits significant selectivity, with a relative fluorescence intensity (Ig). 617 / I 380 It decreased by 85.51%. Figure 11In comparison with other antibiotics, CQDs@Eu-UiO-66 showed a significant fluorescence response only to NOR, with a marked increase in fluorescence intensity at 430 nm and a significant decrease at 617 nm. These results indicate that CQDs@Eu-UiO-66 exhibits good selectivity for most common metal ions or antibiotics and can be used for Hg. 2+ And NOR ion fluorescence sensing.
[0040] (vi) Fluorescence sensitivity analysis like Figure 12-15 As shown, with Hg 2+ With increasing concentration, the fluorescence intensity of the probe at 380 nm and 617 nm gradually decreased. As the NOR concentration increased from 0 to 40 μM, the fluorescence intensity of CQDs@Eu-UiO-66 gradually increased at 430 nm, while the fluorescence intensity at 617 nm gradually decreased. In the low concentration range, the ratiometric fluorescence response of CQDs@Eu-UiO-66 showed a good linear relationship with the analyte concentration (Hg). 2+ R 2 =0.9991; NOR, R 2 =0.9996), following the Stern-Volmer equation, calculate Hg 2+ and NOR's K SV They are 4.70×10 4 M -1 2×10 3 M -1 The limit of detection (LOD) was calculated using the 3δ method reported in the literature: LOD(Hg) 2+ )=3δ / K SV =2.08 nM, LOD(NOR)=48.96 nM, where δ represents the standard deviation of the blank measurement. The results show that Hg 2+ NOR exhibits a strong fluorescence response and high sensitivity to CQDs@Eu-UiO-66 composite materials, thus improving Hg. 2+ And the practical applicability of NOR detection.
[0041] (vii) Practical Application Analysis This invention develops a method for on-site Hg detection based on CQDs@Eu-UiO-66 and a UV cassette integrated into a smartphone. 2+ and NOR portable sensing devices ( Figure 16 CQDs@Eu-UiO-66 were mixed with different concentrations of Hg. 2+ After mixing with NOR and incubating for 2 min, a significant color change was observed under a 254 nm UV lamp. When CQDs@Eu-UiO-66 was mixed with different concentrations of Hg... 2+When mixed, it presents a light pinkish-purple color, and when mixed with different concentrations of NOR, it presents a purple color. Using color recognition software (Color Picker Application) installed on a smartphone, the fluorescent color signal is converted into RGB values. The ratio of the sum of red (R) and green (G) values to the blue (B) value (R+G) / B is used as Hg. 2+ And an effective indicator for NOR detection. The RGB values of the CQDs@Eu-UiO-66 system show a good linear relationship with the analyte concentration (Hg). 2+ R 2 =0.9956; NOR, R 2 =0.9983). Hg was calculated according to the 3σ standard. 2+ The LOD values for Hg were 0.32 μM and 0.14 μM for NOR, respectively, indicating that the smartphone-assisted fluorescence sensor can detect Hg in real time using a visual quantitative method. 2+ and NOR.
Claims
1. A method for treating Hg 2+ A method for preparing CQDs@Eu-UiO-66, a ratiometric fluorescent probe with high selectivity for NOR, is characterized by, Includes the following steps: ZrCl4, EuCl3·6H2O, CQDs and terephthalic acid were mixed and reacted with DMF organic solvent to prepare CQDs@Eu-UiO-66 composite material through self-assembly.
2. The method for treating Hg as described in claim 1 2+ A method for preparing CQDs@Eu-UiO-66, a ratiometric fluorescent probe with high selectivity for NOR, characterized by: The reaction temperature was 120℃ and the reaction time was 24 hours; the amount of CQDs added was 2~10 mg.
3. The method for treating Hg as described in claim 2 2+ A method for preparing CQDs@Eu-UiO-66, a ratiometric fluorescent probe with high selectivity for NOR, characterized by: The molar ratio of ZrCl4, EuCl3·6H2O and BDC is 1:9:
10.
4. The method of using the Hg treatment according to any one of claims 1-3 2+ The probe prepared by the method of preparing the highly selective ratiometric fluorescent probe CQDs@Eu-UiO-66 with NOR is characterized by: The specific surface area of the fluorescent probe BET is 641~737 m². 2 / g, Langmuir has a specific surface area of 747~832 m². 2 / g, pore volume is 0.344~0.388cm³ 3 / g, with micropore volume of 0.226~0.267cm³. 3 / g, with an average pore size of 1.947~2.353 nm.
5. The probe as described in claim 4 is used for trace or micro-level detection of Hg. 2+ Ions, which have a strong effect on Hg in water 2+ The detection limit is as low as 2.08 nM.
6. The probe as described in claim 4 is used for trace or minute detection of NOR, with a detection limit of 48.96 nM for NOR in water.
7. A method for on-site detection of Hg 2+ The portable sensing device of NOR is characterized by: This includes a CQDs@Eu-UiO-66 and a UV dark box integrated into a smartphone. The smartphone also has color recognition software installed to convert fluorescent color signals into RGB values, where the ratio of the sum of red and green values to the blue value (R+G) / B is used as Hg. 2+ Indicators for NOR detection.