A highly sensitive fluorescence detection method for carbonate ions based on UiO-66-NH2 material

Abstract

The present invention discloses a method for detecting carbonate ions (CO3 2‑ ) fluorescence detection method. The present invention found that CO3 2‑ It can selectively bind to UiO‑66‑NH2 and replace its BDC‑NH2 ligand, thereby making the originally non-fluorescent system produce fluorescence. After systematic research, a method for detecting CO3 based on UiO‑66‑NH2 material has been developed. 2‑ The fluorescence detection method only takes 5 minutes to detect, and the detection sensitivity can reach 0.040μg / mL. At the same time, by utilizing the self-aggregation quenching characteristics of the fluorescent group, high-sensitivity and wide-range detection can be achieved according to the difference in detection time.

Description

Technical Field

[0001] The present invention relates to the field of analysis and detection technology, and in particular to a highly sensitive fluorescence detection method for detecting carbonate ions based on a UiO-66-NH2 material. Background Art

[0002] Carbonate ions (CO3 2- ) affects ecological balance and human health, such as CO3 2- It can regulate the body's acid-base balance, maintain the pH value of seawater, and affect the germination and growth of crops. In addition, CO3 2- It also affects the hardness of water, thus hindering industrial manufacturing. It can be seen that the detection of CO3 is very important in the fields of environment, medicine and industry. 2- With large and extensive demands, researchers have been committed to developing sensitive, accurate and convenient CO3 2- Detection technology.

[0003] Currently, a variety of CO3 2- There are many detection methods, such as colorimetry, electrochemistry, infrared spectroscopy, etc. For example, colorimetry is simple and convenient, but has poor sensitivity; infrared spectroscopy and electrochemistry are highly sensitive, but require expensive detection instruments and are difficult to use on site. However, sensitive, accurate and easy-to-use detection methods for CO3 2- There are still few reports on the method of fluorescence detection. Fluorescence detection has the advantages of high sensitivity, fast response, low cost, and real-time monitoring. More and more people use fluorescent identification materials to identify and detect CO3 2- It has become a hot topic of current research.

[0004] The key to developing a suitable fluorescence method is to prepare a highly specific fluorescent material. MOF is a new type of fluorescent material. Its unique structural characteristics give it advantages such as low dosage, high sensitivity, and good specificity in fluorescence detection. It has shown great application potential in the detection of heavy metals, explosives, and small molecule compounds. In recent years, there have been some reports on the use of MOF fluorescence to detect CO3 2- For example, using IRMOF-10-Eu fluorescence to detect CO3 2- , the detection time takes 2h, and the detection limit is 9.58mM; however, the preparation of this fluorescent material is complex, and the detection mode using Turn off is susceptible to interference. Recently, Xue reported a fluorescence enhancement method for the detection of CO3 based on UiO-66-NH2. 2- The method is based on the principle that CO3 2- The reaction with UiO-66-NH2 resulted in Zr 4+ The change in electron transfer between the node and the ligand BDC-NH2 generates fluorescence. The detection limit of this method is 0.63 mg / L, but the detection time is 20 minutes.

[0005] This study developed a Turn-on fluorescence detection method based on UiO-66-NH2, with a detection limit of 0.040 μg / mL and a detection time of only 5 minutes. It has stronger anti-interference ability and is easy to use. It also performed well in actual spiked detection of river water and tap water, demonstrating great potential for practical applications. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for detecting carbonate ions (CO3 2- ) is a highly sensitive fluorescence detection method, which is applied to the fluorescence detection of anions in water, specifically CO3 2- .

[0007] The concept of the present invention is: due to CO3 2- After being added into UiO-66-NH2, it can react with the Zr 4+ Combination, resulting in the original and Zr 4+ The ligand BDC-NH2 falls off, and the ligand produces fluorescence under ultraviolet excitation.

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] The present invention provides a method for detecting carbonate ions (CO3 2- ) is a highly sensitive fluorescence detection method, comprising the following steps:

[0010] S1: Mix UiO-66-NH2 with distilled water at pH 6-8 to prepare a uniform suspension of 0.5-2 mg / mL;

[0011] S2: Containing carbonate ions (CO3 2- ) was added to the suspension, and then shaken and shaken at room temperature until uniform to obtain a mixed solution;

[0012] S3: filtering the mixed solution to obtain a filtrate;

[0013] S4: The filtrate is placed in a quartz dish and placed in a fluorescence spectrometer for detection;

[0014] The UiO-66-NH2 has a grain size of 100-200 nm and a specific surface area of 650-950 m 2 / g;

[0015] The fluorescence spectrum is used under the following conditions: an excitation wavelength of 280 to 360 nm, an emission wavelength of 300 to 600 nm, and an optimal excitation wavelength of 330 ± 5 nm.

[0016] Preferably, the carbonate ion (CO3 2- ) The amount of water sample added should not exceed 100μl.

[0017] Preferably, in step S2, when CO3 2- When the detection range is 10-200 μg / mL and the shaking time at room temperature is no more than 4 min, the detection limit is 0.040 μg / mL.

[0018] Preferably, in step S2, when CO3 2- When the detection range is 100-500 μg / mL and the shaking time at room temperature is no more than 29 minutes, the detection limit is 29.48 μg / mL.

[0019] Preferably, in step S3, the mixed solution is filtered using a 0.22 μM filter membrane.

[0020] Preferably, the concentration of UiO-66-NH2 material in the suspension in step S1 is 1 mg / mL.

[0021] Preferably, in step S4, the fluorescence spectrum is used under the following conditions: a slit width of 5 nm and an electron multiplier tube voltage of 700 V.

[0022] Preferably, in step S4, the fluorescence spectrum is used under the following conditions: the excitation wavelength is 325-335 nm.

[0023] Preferably, the carbonate ions (CO3 2- ) concentration is more than 20 times the total concentration of interfering ions; the interfering ions are HCO3 - PO4 3- 、H2PO4 - 、HPO4 2- , PPi (polyphosphate ion), NO2- and F-, or a mixture of two or more thereof.

[0024] Preferably, carbonate ions are added to UiO-66-NH2 and react with the Zr 4+ Binding causes the ligand BDC-NH2 originally attached to Zr4+ to fall off. The ligand BDC-NH2 produces fluorescence under ultraviolet excitation, which weakens as the concentration of the organophosphorus compound increases. The carbonate ion concentration is determined by constructing a linear relationship between the fluorescence intensity and the carbonate ion concentration.

[0025] Beneficial effects of the present invention: The present invention has found that CO3 2-It can selectively combine with UiO-66-NH2 and replace its BDC-NH2 ligand, thereby making the originally non-fluorescent system produce fluorescence. After systematic research, a method for detecting CO3 based on UiO-66-NH2 material was developed. 2- This fluorescence detection method requires only 5 minutes, achieves a sensitivity of 0.040 μg / mL, and covers a detection range of 10 to 200 μg / mL. Furthermore, by utilizing the self-aggregation quenching characteristics of fluorescent groups, high sensitivity and a wide detection range can be achieved by varying the detection time. When the detection time is 30 minutes, the detection range reaches 100 to 500 μg / mL, with a sensitivity of 29.48 μg / mL. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a scanning electron microscope photograph of UiO-66-NH2 used in Example 1;

[0028] Figure 2 X-ray diffraction pattern of UiO-66-NH2 used in Example 1;

[0029] The vertical axis is the diffraction intensity, and the horizontal axis is 2 times the diffraction angle (degrees)

[0030] a.UiO-66-NH2 (simulation calculation), b.UiO-66-NH2 (preparation), c.UiO-66-NH2 (after use)

[0031] Figure 3 UiO-66-NH2 and CO3 used in Example 1 2- After 5 minutes of reaction, CO3 2- Concentration and fluorescence spectrum intensity change diagram;

[0032] The vertical axis is the fluorescence intensity, and the horizontal axis is the wavelength (nanometers)

[0033] Figure 4 UiO-66-NH2 and CO3 used in Example 1 2- After 5 minutes of reaction, CO3 2- Linear relationship graph between concentration and fluorescence intensity;

[0034] The vertical axis is the fluorescence intensity, and the horizontal axis is the concentration (μg / L)

[0035] Figure 5 UiO-66-NH2 used in Example 1 to detect CO3 2- When the concentration of anions Cl-, AC-, NO3-, SO4 is 200μg / mL 2- 、SO3 2- , CA 3- Interference with detection;

[0036] The vertical axis is the percentage of fluorescence intensity, and the horizontal axis is the percentage of interference.

[0037] Figure 6 UiO-66-NH2 used in Example 1 to detect CO3 2- When the concentration of anion HCO3 is 200μg / mL - 、F-、PO4 3- 、NO2 - and PPi (polyphosphate ion) interference with detection;

[0038] The vertical axis is the percentage of fluorescence intensity, and the horizontal axis is the percentage of interference.

[0039] Figure 7 The UiO-66-NH2 used in Example 1 and CO3 in different water samples 2- After 5 minutes of reaction, the fluorescence intensity changes; CO3 2- The concentration is 100 μg / L;

[0040] The vertical axis is the fluorescence intensity, the horizontal axis is: a. distilled water, b. tap water, c. lake water

[0041] Figure 8 The UiO-66-NH2 used in Example 1 and CO3 in different water samples 2- After 5 minutes of reaction, the fluorescence intensity changes; CO3 2- The concentration is 100 μg / L;

[0042] The vertical axis is the fluorescence intensity, the horizontal axis is: a. distilled water, b. tap water, c. lake water

[0043] Figure 9 UiO-66-NH2 and CO3 used in Example 2 2- After 30 minutes of reaction, CO3 2- Concentration and fluorescence spectrum intensity change diagram;

[0044] The vertical axis is the fluorescence intensity, and the horizontal axis is the wavelength (nanometers)

[0045] Figure 10 UiO-66-NH2 and CO3 used in Example 2 2-After 30 minutes of reaction, CO3 2- The linear relationship between concentration and fluorescence intensity.

[0046] The vertical axis is the fluorescence intensity, and the horizontal axis is the concentration (μg / L) DETAILED DESCRIPTION

[0047] The embodiment of the present invention provides a method for detecting carbonate ions (CO3 2- ) is a highly sensitive fluorescence detection method.

[0048] Example 1

[0049] (1) Using distilled water with a pH value of 6, the crystal size is about 200nm and the specific surface area is about 870m 2 / g UiO-66-NH2 was mixed to prepare a 1mg / mL UiO-66-NH2 suspension, and shaken for 60 seconds to keep the suspension uniform. The scanning electron microscope photo of UiO-66-NH2 is shown in Figure 1 , the X-ray diffraction pattern of UiO-66-NH2 is shown in Figure 2 .

[0050] (2) Prepare NaCO3 solution using distilled water, add 10 μl of NaCO3 solution of different concentrations to 4 mL of 1 mg / mL UiO-66-NH2 suspension, shake for 60 seconds, and place on a shaker for 4 minutes. Then filter the mixed suspension using a 0.22 μM filter membrane, and place 3 mL of the filtrate in a quartz dish with a width of 1 cm and place it in a fluorescence spectrum for detection.

[0051] (3) The fluorescence spectrum was detected using Dongpeng F-380. The fluorescence spectrum conditions were as follows: excitation wavelength of 330±5nm, emission wavelength of 300-600nm, slit width of 5nm, electron multiplier voltage of 700V, and detection concentrations of 10, 50, 100, 150, and 200μg / mL CO3 2- The fluorescence produced Figure 3 As shown, the fluorescence intensity (FL) is related to CO3 2- The concentration (C, μg / mL) showed a linear detection relationship: FL = 25.20C + 3.1 (R 2 =0.997), the detection range of this method is 10-200 μg / mL, and the detection limit is 0.040 μg / mL. Figure 4 shown.

[0052] (4) In the detection of CO3 2- ions, add Cl at a concentration of 200 μg / mL - Br - 、NO3- 、SO4 2- 、AC - Common anions in water, such as Figure 5 As shown, the fluorescence intensity of the solution was measured to be basically unchanged, that is, it had no effect on the detection.

[0053] (5) HCO3 with a concentration of 200 μg / mL - PO4 3- 、NO2 - 、F - Anions and PPi (polyphosphate ions) were added to the UiO-66-NH2 solution, and the detection was carried out according to the above method. It can be seen that the above ions can significantly cause fluorescence enhancement, which has a greater interference with the detection, such as Figure 6 In order to avoid the influence of the above ions on the detection, the total concentration of the above ions can be controlled to be less than the CO3 2- 1 / 20 of the concentration.

[0054] (6) The method is the same as above. The NaCO3 solution is prepared by using lake water with a pH of 7, tap water and distilled water with a pH of 6. 10 μl of NaCO3 solution is added to make the NaCO3 concentration in 4 mL of 1 mg / mL UiO-66-NH2 suspension 200 and 100 μg / mL. It can be seen that the same concentration of CO3 is detected in lake water and tap water. 2- The fluorescence produced is slightly weaker than that produced by testing in distilled water, but it does not affect normal testing, such as Figure 7 、 Figure 8 shown.

[0055] Example 2

[0056] The main difference between this embodiment and embodiment 1 is that the shaking time in the shaking table is delayed from 4 minutes to 29 minutes.

[0057] (1) Using the same 1 mg / mL UiO-66-NH2 suspension as in Example 1, 10 μl of the above-mentioned NaCO3 solution was added to 4 mL of the 1 mg / mL UiO-66-NH2 suspension, shaken for 60 seconds, and placed on a shaker for 29 minutes. The mixed suspension was then filtered using a 0.22 μM filter membrane, and 3 mL of the filtrate was placed in a quartz dish with a width of 1 cm and placed in a fluorescence spectrum for detection.

[0058] (2) Using the same Dongpeng F-380 fluorescence spectrum as in Example 1, the detection concentrations of CO3 were 100, 200, 300, 400, and 500 μg / mL. 2- The fluorescence changes produced are as follows Figure 9 As shown, the fluorescence intensity (FL) is related to CO3 2-The concentration (C, μg / mL) showed a linear detection relationship: FL = 3.39C (R 2 =0.98), the detection range is 100-500 μg / mL, and the detection limit is 29.48 μg / mL. Figure 10 shown.

[0059] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A highly sensitive fluorescence detection method for detecting carbonate ions based on UiO-66-NH2 material, characterized in that: The specific steps include: S1: Mix UiO-66-NH2 with distilled water to prepare a uniform suspension of 0.5-2 mg / mL; S2: adding a water sample containing carbonate ions to the suspension, and then shaking it at room temperature until it is homogeneous to obtain a mixed solution; When CO3 2- When the detection range is 100-500 μg / mL and the shaking time at room temperature is no more than 29 min, the detection limit is 29.48 μg / mL; The carbonate ion concentration in the water sample is more than 20 times the total concentration of interfering ions; the interfering ions are HCO3 - PO4 3- 、H2PO4 - 、HPO4 2- , polyphosphate ions, NO2 - and F - Any one or a mixture of two or more; S3: filtering the mixed solution to obtain a filtrate; S4: The filtrate is placed in a quartz dish and placed in a fluorescence spectrometer for detection; The UiO-66-NH2 has a grain size of 100-200 nm and a specific surface area of 650-950 m 2 / g; The fluorescence spectrum was used under the following conditions: an excitation wavelength of 280-360 nm, and an emission wavelength of 300-600 nm.

2. The highly sensitive fluorescence detection method according to claim 1, wherein The amount of the carbonate ion-containing water sample added in step S2 is no more than 100 μl.

3. The highly sensitive fluorescence detection method according to claim 2, wherein: In step S2, when CO3 2- When the detection range is 10~200 μg / mL and the shaking time at room temperature is no more than 4 minutes, the detection limit is 0.040 μg / mL.

4. The highly sensitive fluorescence detection method according to claim 1, wherein In the step S3, the mixed solution is filtered using a 0.22 μM filter membrane.

5. The highly sensitive fluorescence detection method according to claim 1, wherein The concentration of the UiO-66-NH2 material in the suspension in step S1 is 1 mg / mL.

6. The highly sensitive fluorescence detection method according to claim 1, wherein In step S4, the fluorescence spectrum is used under the following conditions: a slit width of 5 nm and an electron multiplier voltage of 700 V.

7. The highly sensitive fluorescence detection method according to claim 6, wherein In step S4, the fluorescence spectrum is used under the following conditions: an excitation wavelength of 325-335 nm.

8. The fluorescence detection method according to any one of claims 1 to 7, wherein: After carbonate ions are added to UiO-66-NH2, they react with the Zr 4+ Combination, resulting in the original and Zr 4+ The ligand BDC-NH2 is detached, and the fluorescence generated by the ligand BDC-NH2 under ultraviolet excitation decreases with the increase of the concentration of the organophosphorus compound. The carbonate ion concentration is determined by constructing a linear relationship between the fluorescence intensity and the carbonate ion concentration.

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