A fluorescence-enhanced polymer probe for rapid detection of Cr(III) and a synthesis method and application thereof

Abstract

The application belongs to the technical field of fluorescent probe, and particularly relates to a fluorescence-enhanced polymer probe for rapidly detecting Cr(III) as well as a synthesis method and application thereof. The method comprises the following steps: 1) obtaining compound 1 by using 2,7-dibromo phenanthrene-9,10-dione, ammonium acetate and p-hydroxybenzaldehyde; and 2) obtaining the fluorescence-enhanced polymer probe for rapidly detecting Cr(III) by using compound 1 and 2,7-bis(4,4,5,5-tetramethyl-1,3-dioxo-2-borane)-9,9-dibutyric acid ethyl ester-fluorene. The probe provided by the application has the advantages of low fluorescence background, high sensitivity, strong anti-interference ability and good selectivity.

Description

Technical Field

[0001] This invention belongs to the field of fluorescent probe technology, specifically relating to a fluorescently enhanced polymer probe for rapid detection of Cr(III), its synthesis method, and its application. Background Technology

[0002] Chromium exists primarily in nature as Cr(III) and Cr(VI). Cr(III) is an essential trace element for humans and animals, playing a role in regulating the metabolism of sugars and cholesterol. It also plays a crucial role in insulin metabolism; excessive or insufficient Cr(III) can lead to impaired bodily functions and a range of diseases, such as arteriosclerosis, diabetes, and uremia. As a heavy metal, chromium pollutes the environment and water resources. When chromium ions enter water bodies, they enter fish and livestock, eventually reaching humans through the food chain, posing a significant threat to human health. In recent years, several detection methods, such as spectrophotometry, atomic absorption spectrometry (AAS), inductively coupled plasma atomic emission spectrometry / mass spectrometry (ICP-AES / MS), electrochemical methods, and coupled techniques, have been applied to the detection of Cr(III). However, the application of Cr(III) detection is severely limited by factors such as low selectivity and sensitivity, high cost, and high energy consumption.

[0003] Compared with existing technologies, developing detection methods with advantages such as low cost, simple operation, and high sensitivity is of great significance. A key part of fluorescent probe design is the binding of the probe to Cr(III). Cr(III) typically has a good affinity for N and O, which is one of the starting points for most ingeniously designed Cr(III) fluorescent probes. Currently, most polymer fluorescent probes exhibit quenching phenomena in the detection of metal ions; therefore, designing and developing polymer fluorescent probes that exhibit fluorescence enhancement in the detection of metal ions is extremely important. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a rapid fluorescence-enhanced polymer probe for detecting Cr(III), its synthesis method, and its applications. The probe provided by this invention not only possesses advantages such as low fluorescence background, high sensitivity, strong anti-interference ability, and good selectivity, but can also be used as a luminescent material.

[0005] The technical solution provided by this invention is as follows: A fluorescence-enhanced polymeric probe for rapid detection of Cr(III) has the following general formula: ; Where n = 10 - 20.

[0006] The polymer probe (hereinafter referred to as PL) provided by this invention can recognize Cr(III) and exhibits obvious fluorescence enhancement.

[0007] This invention also provides a method for synthesizing the above-mentioned fluorescence-enhanced polymer probe for rapid detection of Cr(III), the synthetic route of which is as follows: This reaction is a typical Debus–Radziszewski reaction; .

[0008] This reaction is a typical Suzuki coupling reaction. Specifically, the synthetic method includes the following steps: 1) Dissolve appropriate amounts of 2,7-dibromophenanthrene-9,10-dione, ammonium acetate, and p-hydroxybenzaldehyde in glacial acetic acid, place in a reaction vessel, and maintain the reaction at 80-90 degrees Celsius for 1.5-2.5 h. Increase the temperature to 115-130 degrees Celsius and react for 2 h. After stopping the reaction, dilute with water, adjust the pH to neutral, filter, wash, and purify the crude product by column chromatography to obtain compound 1. 2) Compound 1 and ethyl 2,7-bis(4,4,5,5-tetramethyl-1,3-dioxo-2-borane)-9,9-dibutyrate-fluorene (as compound 2) were dissolved in DMF. Then, appropriate amounts of catalyst and K2CO3 solution were added sequentially. The temperature was maintained at 115-125 degrees Celsius, preferably 120 degrees Celsius, under an inert atmosphere for 44-52 h, preferably 48 h. After the reaction was completed, the mixture was cooled to room temperature, poured into an appropriate amount of acetonitrile, stirred, filtered, washed, and dried to obtain polymer PL, which is the fluorescence-enhanced polymer probe for rapid detection of Cr(III).

[0009] Specifically, in step 1), the molar ratio of 2,7-dibromophenanthrene-9,10-dione to ammonium acetate is 1:(27-33), preferably 1:30; the molar ratio of 2,7-dibromophenanthrene-9,10-dione to p-hydroxybenzaldehyde is 1:(0.9-1.1), preferably 1:1.

[0010] Specifically, in step 2), the molar ratio of compound 1 to compound 2 is 1:(0.9-1.1), preferably 1:1.

[0011] This invention also provides the application of a fluorescence-enhanced polymer probe for the rapid detection of Cr(III) in simulated water samples.

[0012] Specifically, the fluorescence intensity of probe PL showed a good linear relationship with the concentration of Cr(III) (3.6-5 μM) (RL). 2=0.99235), the detection limit for Cr(III) was 3.54×10 -8 M. This range meets the requirements for the highest permissible concentration of Cr(III) in agricultural irrigation water and fishery water.

[0013] The fluorescent probe PL provided by this invention has good stability, low cost, and does not require a complex synthesis process or expensive instruments, effectively improving the problems of high cost, low stability and complex material synthesis process of existing technologies.

[0014] The fluorescent probe PL provided by this invention has the advantages of high selectivity, high sensitivity, good safety, low cost, and simple operation. Attached Figure Description

[0015] Figure 1 This is a chemical structural diagram of the fluorescent probe PL prepared in Example 1; Figure 2 This is a synthesis route diagram of the fluorescent probe PL prepared in Example 1; Figure 3 The fluorescent probe PL prepared in Example 1 exhibits selective fluorescence spectra for different metal ions in DMSO. Figure 4 The fluorescence response diagram of the fluorescent probe PL prepared in Example 1 to selective interference detection of different metal ions in DMSO is shown. Figure 5 The fluorescence spectrum of the fluorescent probe PL prepared in Example 1 in DMSO as the concentration of Cr(III) increases; Figure 6 This is a curve showing the fluorescence intensity of the fluorescent probe PL prepared in Example 1 in DMSO as the concentration of Cr(III) increases. Figure 7 The infrared spectrum of the fluorescent probe PL prepared in Example 1; Figure 8 The image below shows the fluorescent probe PL prepared in Example 1 after being reacted with different metal ions under a 365 nm ultraviolet light. Figure 9 The fluorescence spectra of the fluorescent probe PL in DMSO-H2O test systems with different water contents are shown. Detailed Implementation

[0016] The principles and features of the present invention are described below. The embodiments given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0017] Example 1 Synthesis of a rapid fluorescence-enhanced polymer probe for detecting Cr(III), named PL, with its chemical structure (see attached diagram). Figure 1 ).

[0018] The synthesis method of the above-mentioned rapid detection Cr(III) fluorescence-enhanced probe polymer specifically includes the following steps: Step 1, Synthesis of Compound 1: 2,7-Dibromophenanthrene-9,10-dione (0.5 g, 1.366 mmol), ammonium acetate (1.575 g, 40.98 mmol), and p-hydroxybenzaldehyde (0.166 g, 1.366 mmol) were dissolved in glacial acetic acid (17.5 mL) and placed in a 50 mL round-bottom flask. The reaction was carried out at 85°C for 2 h, then the temperature was increased to 122.5°C and the reaction was continued for 2 h. After the reaction was stopped, water (200 mL) was added to dilute the product. The pH was adjusted to neutral with concentrated ammonia, and the product was filtered and washed. The crude product was purified by silica gel column chromatography to obtain Compound 1. 1 H NMR (400 MHz, DMSO- d 6, δ (ppm)): 6.97 (d, 2H), 7.72 (d, 2H), 8.10 (d, 2H), 8.76 (dd, 4H), 10.01 (s, 1H, OH), and 11.96 (s, 1H, NH); 13 C NMR (101 MHz, DMSO-) d 6, δ (ppm)): 172.16, 159.10, 150.56, 128.08, 127.79, 126.21,125.67, 124.00, 120.95, 120.91, 115.82, 21.14; HRMS (ESI, m / z) calcd forC 21 H 12 Br2N2O (M+H)+: 468.9397, found: 468.9380.

[0019] Step 2: Compound 1 (0.1616 g, 0.25 mmol), compound 2 (2,7-bis(4,4,5,5-tetramethyl-1,3-dioxo-2-borane)-9,9-dibutyrate ethyl fluorene, 0.117 g, 0.25 mmol), Pd(PPh3)4 (4 mg), and 2 M K2CO3 (2 mL) prepared in step (1) were dissolved in 10 mL DMF. The mixture was stirred in an oil bath at 120°C under a nitrogen atmosphere for 48 hours. After the reaction, the mixture was cooled to room temperature and precipitated as a green solid in 100 mL acetonitrile. The solid was washed with deionized water and dried to obtain the crude polymer product. The obtained solid was successively extracted with petroleum ether, ethanol, methanol, and tetrahydrofuran for 12 h. Finally, the ethanol solution was concentrated, evaporated, and dried to obtain the pale green fluorescent probe PL.

[0020] The surface functional groups of the fluorescent probe PL prepared in Example 1 were analyzed using infrared spectroscopy, and the results are as follows: Figure 7 As shown. At 1629 cm -1 The characteristic absorption peak for C=N is at 1403 cm⁻¹. -1 The characteristic absorption peak of C=C is at 1096 cm⁻¹. -1 The peak at this location is the characteristic absorption peak of COC, thus proving that the fluorescent probe L was successfully synthesized.

[0021] The fluorescent probe PL described above can be used to identify Cr(III).

[0022] Within a certain range, the fluorescence intensity of the aforementioned fluorescent probe PL showed a good linear relationship with the concentration of Cr(III), and the detection limit was 3.54 × 10⁻⁶. -8 M.

[0023] Example 2 To evaluate the performance of the fluorescent probe PL on Cr(III) and verify its selectivity for Cr(III) in DMSO, such as... Figure 3 The figure shows the fluorescent probe PL (1×10⁻⁶). -5 Different metal ions (2×10 mol / L) were added respectively. -5 mol / L)(Na + Mg 2+ Ca 2+ Cd 2+ Cr 3+ Li + Ba 2+ Mn 2+ K + Fe 2+ Fe 3+ Co 2+ Ni 2+ Cu2+ 、Sr 2+ Al 3+ Ag + Zn 2+ Hg 2+ Pb 2+ Fluorescence changes (λ) ex =370 nm; slit ex / em = 5.0 nm / 5.0 nm). Besides the addition of Al 3+ and Fe 3+ When ions are added, the fluorescence intensity of the system shows a slight increase. Only when Cr(III) is added does the fluorescence intensity increase significantly (approximately 45-fold), while other metal ions do not produce obvious fluorescence enhancement. The results indicate that the fluorescent probe PL has good selectivity for Cr(III).

[0024] Furthermore, interference resistance is another important indicator for evaluating a superior sensor; therefore, such as... Figure 4 The image shows a bar chart of fluorescence intensity for Cr(III) in the presence of different interfering ions. The fluorescence intensity of the fluorescent probe PL (1×10⁻⁶) is also shown. -5 Different metal ions (2×10⁻⁶) were added to the solution at mol / L. -5 mol / L)(Na + Mg 2+ Ca 2+ Cd 2+ Cr 3+ Li + Ba 2+ Mn 2+ K + Fe 2+ Fe 3 + Co 2+ Ni 2+ Cu 2+ 、Sr 2+ Al 3+ Ag + Zn 2+ Hg 2+ Pb 2+ After that, Cr(III)(2×10) was added under the condition of the presence of the above interfering ions. -5 mol / L), and its fluorescence intensity (λ) was measured. ex =370 nm; slit ex / em = 5.0 / 5.0 nm). The results show that the fluorescent probe PL exhibits significant fluorescence enhancement upon the addition of Cr(III). Furthermore, the fluorescence response remains largely unaffected by the addition of Cr(III) in the presence of common interfering substances. This indicates that the fluorescent probe PL has excellent anti-interference performance.

[0025] Example 3 Performance testing of the fluorescent probe PL for quantitative analysis of Cr(III). For example... Figure 5 As shown, 3 μL of fluorescent probe PL (1×10⁻⁶) was added to 3 mL of DMSO. -2 moL / L) and Cr(III) (1×10 -2 moL / L) solution (0 μM, 0.01 μM, 0.1 μM, 1 μM, 2 μM, 2.4 μM, 2.8 μM, 3 μM, 3.2 μM, 3.4 μM, 3.5 μM, 3.6 μM, 3.7 μM, 3.8 μM, 3.9 μM, 4 μM, 4.3 μM, 4.5 μM, 4.7 μM, 5 μM, 6 μM, 6.4 μM, 6.8 μM, 7 μM, 7.1 μM, 7.2 μM, 7.3 μM, 7.4 μM, 7.5 μM, 7.6 μM, 7.7 μM, 7.8 μM, 7.9 μM, 8 μM, 9 μM, 10 μM, 15 μM, 20 μM, 25 μM, 30 The fluorescent probe PL was tested in DMSO at a concentration of μM. It exhibited pale yellow fluorescence, but the fluorescence at 489 nm increased with increasing Cr(III) concentration, accompanied by a significant color change. The Cr(III) concentration ranged from 3.6 to 5 μM (see Appendix for details). Figure 6 The fluorescent probe PL showed a good linear relationship with the concentration of Cr(III) (R0). 2 =0.99235), according to the detection limit formula: LOD=3σ / k (where σ is the standard deviation and k is the slope of the line), the detection limit is calculated to be 3.54×10. -8 M indicates that the fluorescent probe PL has high sensitivity for recognizing Cr(III).

[0026] Example 4 like Figure 8 As shown, 3 μL of fluorescent probe PL (1×10⁻⁶) was added to 3 mL of DMSO. -2 (mol / L) as a control ( Figure 8 The first one in the first row), then add different metal ions (2×10). -5 mol / L)(Na + Mg 2+ Ca 2+ Cd 2+ Cr 3+ Li + Ba 2+ Mn 2+ K + Fe 2+ Fe3+ Co 2+ Ni 2+ Cu 2+ 、Sr 2+ Al 3+ Ag + Zn 2+ Hg 2+ Pb 2+ When the prepared solution was irradiated with a handheld UV lamp (365 nm), only Cr... 3+ The solution containing Cr exhibited a distinct blue fluorescence (seventh in the first row), while solutions containing other metal ions showed almost no color change. Using diphenylanthracene as a reference, the fluorescence quantum yield increased from 4.7% before addition to 13.7% after addition. This indicates that the fluorescent probe PL can enhance the fluorescence of Cr. 3+ Selective detection.

[0027] Example 5 AIEE effect of fluorescent probe PL, such as Figure 9 The AIEE effect of the fluorescent probe PL was investigated in systems with different volume ratios of DMSO and water (water content ranging from 0% to 90%). Figure 9 As shown, the fluorescence intensity of the fluorescent probe PL increases with increasing water content, and a significant blue shift (from 522 nm to 486 nm) occurs when the water content reaches 5%. This indicates that the fluorescent probe PL exhibits aggregation-induced fluorescence enhancement.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A fluorescence-enhanced polymer probe for rapid detection of Cr(III), characterized in that, Its general formula is as follows: Where n = 10 - 20.

2. A method for synthesizing a fluorescence-enhanced polymer probe for rapid detection of Cr(III) according to claim 1, characterized in that, Its synthetic route is as follows:

3. The synthesis method according to claim 2, characterized in that, Includes the following steps: 1) Dissolve appropriate amounts of 2,7-dibromophenanthrene-9,10-dione, ammonium acetate, and p-hydroxybenzaldehyde in glacial acetic acid, place in a reaction vessel, and maintain the reaction at 80-90 degrees Celsius for 1.5-2.5 hours. Increase the temperature to 115-130 degrees Celsius and react for 2 hours. After stopping the reaction, dilute with water, adjust the pH to neutral, filter, wash, and purify the crude product by column chromatography to obtain compound 1. 2) Compound 1 and ethyl 2,7-bis(4,4,5,5-tetramethyl-1,3-dioxo-2-borane)-9,9-dibutyrate-fluorene (as compound 2) were dissolved in DMF. Then, appropriate amounts of catalyst and K2CO3 solution were added sequentially. The temperature was maintained at 115-125 degrees Celsius under an inert atmosphere for 44-52 hours. After the reaction was completed, the mixture was cooled to room temperature, poured into an appropriate amount of acetonitrile, stirred, filtered, washed, and dried to obtain polymer PL, which is the fluorescence-enhanced polymer probe for rapid detection of Cr(III).

4. The synthesis method according to claim 2, characterized in that, In step 1): The molar ratio of 2,7-dibromophenanthrene-9,10-dione to ammonium acetate is 1:(27-33); The molar ratio of 2,7-dibromophenanthrene-9,10-dione to p-hydroxybenzaldehyde is 1:(0.9-1.1).

5. The synthesis method according to claim 2, characterized in that: In step 2), the molar ratio of compound 1 to compound 2 is 1:(0.9-1.1).

6. An application of the fluorescence-enhanced polymer probe for rapid detection of Cr(III) according to claim 1, characterized in that: When Cr(III) was added to the DMSO solution of polymer PL, the fluorescence of the solution was significantly enhanced, and the color changed from colorless to blue under a 365 nm UV lamp.

7. The application according to claim 6, characterized in that: The detection limit for Cr(III) was 3.54 × 10⁻⁶. -8 M.

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