CN116496786B

CN116496786B - Gadolinium nanocluster fluorescent probe and application thereof in environment detection

Info

Publication number: CN116496786B
Application number: CN202310795958.3A
Authority: CN
Inventors: 张菲; 肖皓月; 韩亚萌; 李书鹏; 王蓓丽; 郭丽莉
Original assignee: Tianjin Normal University; BCEG Environmental Remediation Co Ltd
Current assignee: Tianjin Normal University; BCEG Environmental Remediation Co Ltd
Priority date: 2023-07-01
Filing date: 2023-07-01
Publication date: 2023-09-29
Anticipated expiration: 2043-07-01
Also published as: CN116496786A

Abstract

The invention discloses a gadolinium nanocluster fluorescent probe and application thereof in environment detection. Adding template molecule N- (2-mercaptopropionyl) glycine into a soluble gadolinium salt solution, adding a reducing agent to be completely dissolved, adjusting the pH value to 5.0-7.0 by using alkali liquor, stirring for reaction, freeze-drying the solution, centrifugally washing by using ethanol, and drying to obtain the gadolinium nanocluster fluorescent probe. Fluorescent probe fluorescence energy based on gadolinium nanocluster can be coated with Gd ³⁺ Ion quenching characteristics, and application of the ion quenching characteristics to water environment pollutant Gd ³⁺ Fluorescence detection of ions, wherein the linear detection range is 1-100 mu M; the detection limit is 89nM, and has high selectivity and sensitivity and wide application prospect.

Description

Gadolinium nanocluster fluorescent probe and application thereof in environment detection

Technical Field

The invention belongs to an environmental pollutant Gd ³⁺ The technical field of ion detection, in particular to a gadolinium nanocluster fluorescent probe and application thereof in environmental detection.

Background

Trivalent ion Gd of rare earth element gadolinium ³⁺ The ion with the highest spin value in the nature is widely applied to the fields of magnetic material manufacturing, semiconductor industry, electronic industry, magnetic resonance imaging contrast agent and the like because of the extremely excellent paramagnetic property, and is possibly accumulated in water bodies, soil, crops and animals and invaded into human bodies through food chains as industrial wastewater is discharged into the ecological environment. In addition, gadolinium formulations are also currently clinically more popular Magnetic Resonance Imaging (MRI) contrast agents. By Gd ³⁺ Gadolinium-containing contrast agents represented by diethylenetriamine pentaacetic acid complex (Gd-DTPA), gadoteridol (Gd-DOTA), gadoteridol, gadobutrol, and the like can be metabolized by the kidney after being injected into a human body, but also cause certain in vivo gadolinium deposition, which adversely affects the health of the human body. This is because of the free form of Gd ³⁺ The ions have extremely high biotoxicity, and can cause damage to human kidneys and brains, and induce symptoms such as organ failure, mental abnormality, muscle strength decline, hypomnesis and the like. Thus Gd ³⁺ Ions are a serious hazardous heavy metal contaminant, and Gd is monitored in an environmental sample ³⁺ The ion content is of great importance.

Compared with the traditional atomic light/mass spectrometry, electrochemical analysis and titration analysis methods, the fluorescence spectrometry has the advantages of high sensitivity, good reproducibility, simple and rapid method, low analysis cost and the like, and is a powerful means for constructing an accurate, rapid, efficient and sensitive analysis and detection method for heavy metal pollutants in a complex environment medium, and the construction of the sensitive fluorescence analysis method is not independent of the development of a fluorescence probe with excellent performance.

Disclosure of Invention

The invention aims to provide a high-performance gadolinium nanocluster fluorescent probe, which can be used for fluorescence by Gd ³⁺ The characteristic of quenching of ions realizes the effect of Gd which is an environmental pollutant in aqueous solution ³⁺ The high-sensitivity detection of ions provides a new technical scheme for the field of environmental monitoring.

The preparation method of the gadolinium nanocluster fluorescent probe comprises the following steps: adding template molecule N- (2-mercaptopropionyl) glycine into a soluble gadolinium salt solution, adding a reducing agent to dissolve completely, adjusting the pH value to 5.0-7.0 by using alkali liquor, stirring to react, freeze-drying the solution, centrifugally washing by using ethanol, and drying to obtain the gadolinium nanocluster fluorescent probe.

The soluble gadolinium salt is GdCl ₃ 。

The concentration of the soluble gadolinium salt solution is 0.01-0.1M.

The molar ratio of the template molecule to gadolinium is 10-15:1.

The reducing agent is ascorbic acid.

The molar ratio of the reducing agent to gadolinium is 1.5-2.5:1.

The alkali liquor is NaOH solution.

The prepared gadolinium nanocluster fluorescent probe is used for detecting environmental pollutant Gd ³⁺ Is used in the field of applications.

The detection of the environmental pollutant Gd ³⁺ The method of (1) is as follows: the same volume of water and different concentrations of Gd ³⁺ Selecting a plurality of standard solutions, respectively adding the standard solutions into gadolinium nanocluster fluorescent probe solutions with the same volume, carrying out a fluorescence test after mixing reaction for 5-10min, wherein the difference value between each obtained fluorescence intensity and the maximum fluorescence intensity is fluorescence quenching amount, and taking the fluorescence quenching amount as an ordinate, and Gd ³⁺ Drawing a standard curve by taking the concentration of the standard solution as the abscissa; will be with Gd ³⁺ Mixing the solution to be detected with the same volume of standard solution with the gadolinium nanocluster fluorescent probe solution with the same volume, and carrying out fluorescence test under the same condition, wherein the decrease of fluorescence intensity indicates that Gd is contained ³⁺ According to fluorescence quenching amount and standard curve, gd in the solution to be measured is calculated ³⁺ Is a concentration of (3).

The gadolinium nanocluster fluorescence probeThe concentration of the needle solution was 0.5-1.0 mg/mL. Gadolinium nanocluster fluorescent probe solution and Gd ³⁺ The volume ratio of the standard solution is 10-30:1.

The excitation wavelength of the fluorescence test is 320+/-10 nm.

The emission wavelength of the fluorescence test is in the range of 400-700 nm.

The beneficial effects of the invention are as follows:

(1) The Gd NCs fluorescent probe disclosed by the invention is used for heavy metal environmental pollutant Gd ³⁺ Has sensitive fluorescence response, and the preparation and use cost are lower than those of noble metal fluorescence nanocluster probes.

(2) The Gd NCs fluorescent probe disclosed by the invention can realize the Gd heavy metal environmental pollutant without an additional functional modification process ³⁺ High selectivity and high sensitivity fluorescence detection.

(3) Gd is detected by the detection method disclosed by the invention ³⁺ The detection linearity of (2) is in the range of 1-100. Mu.M; the detection limit is: 89nM, has a wider detection range and a lower detection limit, and has a wide application prospect.

Drawings

FIG. 1 is a transmission electron microscope image of Gd NCs prepared in example 1, illustrating that the synthesized Gd NCs have uniform particle size, smaller particle size, and uniform distribution;

FIG. 2 is a graph of particle size distribution of Gd NCs prepared in example 1, illustrating that the synthesized Gd NCs have a particle size of about 1.7. 1.7 nm, consistent with the particle size scale of metal fluorescent nanoclusters;

FIG. 3 shows Gd NCs prepared in example 1 after the addition of Gd as a target ³⁺ The front and back fluorescence emission spectra show that the Gd NCs probe can detect Gd ³⁺ Generating a fluorescent response;

FIG. 4 shows Gd NCs probe detection Gd prepared in example 1 ³⁺ Is a fluorescence spectrum of Gd ³⁺ The fluorescence of the probe can be effectively quenched within the concentration range of 1-100 mu M;

FIG. 5 shows Gd NCs probe detection Gd prepared in example 1 ³⁺ Is a working graph of Gd ³⁺ The quantitative relationship between the detection concentration and the fluorescence quenching amount of the probe.

Detailed Description

The invention is described below by means of specific embodiments. The embodiments should be considered as illustrative, and not limiting, the scope of the invention being limited only by the claims. Various changes or modifications to the materials ingredients and amounts used in these embodiments will be apparent to those skilled in the art without departing from the spirit and scope of the invention.

The reagents used were analytically pure, as follows: high purity water, haha group limited, hangzhou baby; n- (2-mercaptopropionyl) glycine, a division of organisms (Shanghai); gadolinium chloride, beijing enoki technology limited; ascorbic acid, tianjin light complex fine chemical institute.

Example 1

Preparation of gadolinium nanocluster fluorescent probes (Gd NCs):

(1) 0.1632 g of N- (2-mercaptopropionyl) glycine was weighed as a preparation template and dissolved in 10mL GdCl at a concentration of 0.01M ₃ Fully and uniformly stirring the solution;

(2) Adding 0.0352 g ascorbic acid reducer into the reaction system, adding 0.9mL NaOH solution with the concentration of 1M to regulate the pH value of the reaction system after the ascorbic acid reducer is completely dissolved, and fully stirring and reacting for 70min at room temperature;

(3) And (3) freeze-drying the reaction liquid obtained in the step (2), then centrifugally washing with ethanol, and drying to obtain Gd NCs solid powder.

Transmission Electron Microscope (TEM) characterization of Gd NCs: dispersing the prepared Gd NCs into high-purity water, uniformly dripping the high-purity water on a special copper mesh, airing to prepare an observation sample, and observing the morphology of the observation sample by using a field emission transmission electron microscope. As shown in fig. 1, the morphology of the Gd NCs is approximately spherical and uniformly dispersed, the particle size is small and uniformly distributed, and the particle size distribution diagram (fig. 2) shows that the particle size is about 1.7 and nm, which accords with the average particle size range of the metal fluorescent nanoclusters.

Fluorescence spectrum of Gd NCs and Gd for target object ³⁺ Fluorescent response of (2): setting the excitation wavelength to 320nm, determination of Gd added as target substance by fluorescence spectrophotometer ³⁺ Fluorescence emission spectra of front and back Gd NCs probe dilutions. As a result, as shown in FIG. 3, gd was added as a target ³⁺ The Gd NCs probe has stronger fluorescence emission peak at 480 nm before adding the target Gd ³⁺ The fluorescence emission peak is then reduced by about 30% due to the target Gd in the detection system ³⁺ And Gd atoms in Gd NCs compete for the template molecule to partially disintegrate Gd NCs. The result shows that the fluorescence of Gd NCs probe is obviously quenched, and the probe is used for the target Gd ³⁺ Has good fluorescence response, and the Gd NCs probe can be used for detecting Gd ³⁺ Fluorescence detection was performed.

Gd NCs Probe on Gd ³⁺ Application in detection:

(1) gd of different concentrations ³⁺ Preparing a standard solution: remove Gd at 5.00 mL concentration of 0.05M ³⁺ The aqueous solution is put into a 50 mL volumetric flask, and is added with pure water to fix the volume, and is prepared into Gd with the concentration of 50.00 mL of 5mM ³⁺ The stock solution with high standard is prepared into Gd with concentration of 20 mu M, 100 mu M, 200 mu M, 400 mu M, 600 mu M, 800 mu M, 1000 mu M, 1600 mu M and 2000 mu M by stepwise dilution based on the stock solution ³⁺ A standard solution;

(2) taking 100mg of Gd NCs probe powder, dissolving in 4mL of high-purity water, shaking uniformly to prepare a probe mother solution, diluting the mother solution 40 times, and preparing a Gd NCs diluent with the concentration of 0.625 mg/mL;

(3) adding 3.8mL of Gd NCs diluent and 0.2. 0.2 mL high-purity water into a 5 mL centrifuge tube, vibrating and reacting for 7min on a shaking table, and testing the fluorescence intensity of the test solution as the initial fluorescence intensity F of the probe ₀ Excitation wavelength is 320 nm, emission wavelength is 480 nm;

(4) 9 5 mL centrifuge tubes were taken, 3.8mL of Gd NCs dilution was added to each centrifuge tube, and then 200. Mu.L of Gd at 20. Mu.M, 100. Mu.M, 200. Mu.M, 400. Mu.M, 600. Mu.M, 800. Mu.M, 1000. Mu.M, 1600. Mu.M, 2000. Mu.M were added, respectively ³⁺ Standard solution, gd in the detection system ³⁺ The detection concentrations of (2) were 1. Mu.M, 5. Mu.M, 10. Mu.M, 20. Mu.M, 30. Mu.M, 40. Mu.M, 50. Mu.M, 80. Mu.M, 100. Mu.M, respectively, and after shaking reaction on a shaker for 7min, the detection was performedThe fluorescence intensity F (figure 4) of the probe in the system has an excitation wavelength of 320 nm and an emission wavelength of 480 nm;

(5) the amount of fluorescence quenching of the probe in each system was calculated (F ₀ -F) and on its ordinate, gd in each system ³⁺ The detection concentration of (2) is the abscissa, and a standard curve is drawn, and the experimental result shows that the standard curve is formed on Gd ³⁺ The concentration is 1-100 mu M, and the quenching amount of Gd NCs fluorescence intensity and Gd ³⁺ Shows a linear relationship (FIG. 5) with the linear equation F ₀ -f=0.96 x+17.90, x being Gd ³⁺ The detection limit is 89nM, which indicates that the Gd NCs can be used for environmental pollutants Gd ³⁺ Is a high sensitivity detection of (1).

Example 2

Gd in environmental water sample ³⁺ Ion measurement:

taking 10mL of river water sample, centrifuging at 8000 r/min for 10min to remove suspended matters, collecting supernatant, and filtering with a 0.22 μm microporous membrane to obtain the filtered river water sample to be tested. Taking 3.8mL Gd NCs probe solution (0.625 mg/mL) prepared in example 1, adding 0.2 mL river water sample to be detected, measuring fluorescence intensity after shaking table oscillation reaction for 7min, calculating recovery rate by standard addition method, and obtaining standard addition recovery rate of 97.75% -105.41% as shown in Table 1, which shows that the method can be used for Gd in actual environment water sample ³⁺ And (3) detecting ions.

Claims

1. The preparation method of the gadolinium nanocluster fluorescent probe is characterized by comprising the following specific operations: adding template molecule N- (2-mercaptopropionyl) glycine into a soluble gadolinium salt solution, adding a reducing agent to dissolve completely, adjusting the pH value to 5.0-7.0 by using alkali liquor, stirring to react, freeze-drying the solution, centrifugally washing by using ethanol, and drying to obtain the gadolinium nanocluster fluorescent probe.

2. The preparation method according to claim 1, which isCharacterized in that the soluble gadolinium salt is GdCl ₃ 。

3. The method of claim 1, wherein the concentration of the soluble gadolinium salt solution is from 0.01 to 0.1M.

4. The method of claim 1, wherein the molar ratio of template molecule to gadolinium is 10-15:1.

5. The method according to claim 1, wherein the reducing agent is ascorbic acid; the molar ratio of the reducing agent to gadolinium is 1.5-2.5:1.

6. The method according to claim 1, wherein the alkaline solution is a NaOH solution.

7. Gadolinium nanocluster fluorescent probe prepared by the method according to any one of claims 1-6 for detecting environmental pollutant Gd ³⁺ Is used in the field of applications.

8. The use according to claim 7, wherein the detection of environmental contaminant Gd ³⁺ The method of (1) is as follows: the same volume of water and different concentrations of Gd ³⁺ Selecting a plurality of standard solutions, respectively adding the standard solutions into gadolinium nanocluster fluorescent probe solutions with the same volume, carrying out a fluorescence test after mixing reaction for 5-10min, wherein the difference value between each obtained fluorescence intensity and the maximum fluorescence intensity is fluorescence quenching amount, and taking the fluorescence quenching amount as an ordinate, and Gd ³⁺ Drawing a standard curve by taking the concentration of the standard solution as the abscissa; will be with Gd ³⁺ Mixing the solution to be detected with the same volume of standard solution with the gadolinium nanocluster fluorescent probe solution with the same volume, and carrying out fluorescence test under the same condition, wherein the decrease of fluorescence intensity indicates that Gd is contained ³⁺ According to fluorescence quenching amount and standard curve, gd in the solution to be measured is calculated ³⁺ Is a concentration of (3).

9. The use according to claim 8, wherein the concentration of the gadolinium nanocluster fluorescent probe solution is 0.5-1.0 mg/mL.

10. The use of claim 8, wherein the fluorescence test has an excitation wavelength of 320±10 nm; the emission wavelength of the fluorescence test is in the range of 400-700 nm.