Preparation method of portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3 coated UiO-66 / Ru

Abstract

The invention discloses a preparation method of a portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3 at-UiO-66 / Ru, which comprises the following steps: 1, adding lead bromide and cesium bromide into N, N-dimethylformamide, then adding 5-bromovaleric acid and an oleylamine ligand, and stirring; 2, perfluorooctyltriethoxysilane is added, and a precursor solution is obtained; 3, adding zirconium chloride and terephthalic acid into N, N-dimethylformamide to obtain a homogeneous solution; 4, after heating, UiO-66 is obtained; 5, stirring the precursor solution, APBA, UiO-66 and tris (2, 2-dipyridyl) ruthenium chloride hexahydrate to obtain a composite material; and 6, dropwise adding the composite material solution into the filter paper. The APBA modified material is adopted as a recognition unit, the APBA modified material and the paper base construct a fluorescence sensing platform, visual quantitative analysis of oxytetracycline in water is achieved, and the device is convenient to carry, low in detection limit, high in anti-interference performance, easy and convenient to operate and suitable for on-site rapid detection of oxytetracycline.

Description

Technical Field

[0001] This invention belongs to the field of water environment analysis and detection technology, specifically relating to a method for preparing a portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru. Background Technology

[0002] Oxytetracycline (OTC) is a broad-spectrum tetracycline antibiotic widely used in the medical, aquaculture, and livestock industries due to its low cost and strong antibacterial effect. However, with its increasing usage, it exhibits persistent residues and bioaccumulation in the environment, posing a potential threat to ecosystems and human health. Existing detection methods are limited by expensive instruments and complex operations, making them insufficient to meet practical needs. Therefore, establishing a simple, rapid, and efficient analytical method for the detection of oxytetracycline in the environment is crucial.

[0003] Traditional instrumental analysis techniques are complex and costly, while perovskite quantum dot-based fluorescence detection methods, though rapid, simple, and economical, are limited by the fact that existing sensors are mostly in solution form, making real-time, in-situ detection difficult in fields such as environmental and food testing. Furthermore, since lead-based perovskite quantum dots contain the heavy metal lead, the detection method must minimize sample volume to reduce potential environmental pollution risks and avoid its environmental impact during detection. Therefore, there is a need to develop a rapid, low-dose, on-site fluorescence analysis method based on perovskite quantum dots. Summary of the Invention

[0004] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a method for preparing a portable paper-based ratiometric fluorescence sensor, APBA-CsPbBr3@UiO-66 / Ru. This method utilizes highly selective 3-aminophenylboronic acid to functionalize CsPbBr3PQDs, achieving stable binding through the specific boron affinity between the boric acid groups in APBA and the cis-ortho-dihydroxy groups in OTC molecules. This enhances the sensor's selective recognition ability for OTC and, when combined with a paper-based carrier, constructs a paper-based ratiometric fluorescence sensor. This sensor is characterized by low cost, lightweight design, and portability, meeting the needs for rapid on-site detection and solving the problems of complex operation, expensive instruments, inconvenient detection, and low sensitivity in existing oxytetracycline detection methods.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a method for preparing a portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru, characterized in that it is prepared from the following components: cesium bromide, lead bromide, N,N-dimethylformamide, 5-bromopentanoic acid, oleylamine, perfluorooctyltriethyloxysilane, zirconium chloride, terephthalic acid, ethanol, methyl acetate, ruthenium tri(2,2-bipyridine)chloride hexahydrate, and Whatman NO.1 filter paper; The preparation method includes the following steps: Step 1: Add lead bromide and cesium bromide to N,N-dimethylformamide and stir continuously until completely dissolved. Then, add 5-bromopentanoic acid and oleylamine ligand in sequence, and continue stirring at room temperature to allow the ligand to react fully and obtain a mixed solution. Step 2: Add perfluorooctyltriethyloxysilane to the mixed solution obtained in Step 1 and stir to obtain CsPbBr3PQDs precursor solution; Step 3: Add zirconium chloride and terephthalic acid to N,N-dimethylformamide and sonicate to obtain a homogeneous solution; Step 4: Transfer the homogeneous solution obtained in Step 3 to a reaction vessel lined with polytetrafluoroethylene, and heat the reaction vessel to carry out the reaction. After the reaction is completed, allow the reaction system to cool down to room temperature naturally to obtain a precipitate. Then, wash the precipitate with N,N-dimethylformamide and ethanol in sequence, and after vacuum drying, obtain zirconium-based MOF, i.e., UiO-66. Step 5: Slowly add the CsPbBr3PQDs precursor solution obtained in Step 2 to methyl acetate, and add APBA while stirring in the dark to obtain APBA-CsPbBr3PQDs. Then, add UiO-66 from Step 4 at room temperature and continue stirring to form APBA-CsPbBr3@UiO-66. Then, add ruthenium tris(2,2-bipyridine)chloride hexahydrate and stir. Filter the precipitate and wash it with methyl acetate. After vacuum drying, obtain the APBA-CsPbBr3@UiO-66 / Ru composite material. Step 6: After cutting the Whatman NO.1 filter paper, drop the solution of APBA-CsPbBr3@UiO-66 / Ru composite material from Step 5 onto the surface, and let it air dry at room temperature to obtain the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru.

[0006] The preparation method of the portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru described above is characterized in that the molar ratio of lead bromide to cesium bromide in step one is 1:1, and the molar ratio of 5-bromopentanoic acid to oleylamine ligand is 1:1, 2:1, 0:1, 0.5:1, or 1:0. Preferably, the molar ratio of 5-bromopentanoic acid to oleylamine ligand is 1:1.

[0007] The above-mentioned method for preparing a portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru is characterized in that the ratio of zirconium chloride, terephthalic acid and N,N-dimethylformamide in step three is 0.2330g:0.1661g:20mL.

[0008] The preparation method of the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru is characterized in that the amount of UiO-66 added in step five is 0%, 34.1%, 54.5%, 68.1%, 81.7%, and 102.2% of the mass of lead bromide, the ratio of APBA to tris(2,2-bipyridine)chloride hexahydrate is 0.1487 g: 0.075 g, and the molar ratio of APBA to CsPbBr3PQDs is 1:1.

[0009] The preparation method of the portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru is characterized by the following steps: in step one, the continuous stirring time is 20-40 min, and the further stirring time is 10-20 min; in step two, the stirring time is 10-30 min; in step three, the ultrasonic treatment time is 10-30 min; in step four, the heating temperature is 120℃ and the reaction time is 24 h; the vacuum drying temperature is 60℃ and the time is 10-14 h; in step five, the light-protected stirring time is 2-4 h, the addition of UiO-66 and the continued stirring time is 2 h, the addition of tris(2,2-bipyridine)chloride hexahydrate and the stirring time is 1 h, and the vacuum drying temperature is 60℃ and the time is 4-8 h. The above-mentioned method for preparing a portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru is characterized in that, in step six, Whatman NO.1 filter paper is cut to a length × width of 1.5cm × 1.5cm, and a solution of APBA-CsPbBr3@UiO-66 / Ru composite material of 1.5mg / mL is dropped onto the surface.

[0010] Compared with the prior art, the present invention has the following advantages: 1. This invention uses 3-aminophenylboronic acid (APBA) to functionalize CsPbBr3PQDs, and then combines it with UiO-66 and Ru to prepare APBA-CsPbBr3@UiO-66 / Ru composite material. This composite material is then loaded onto filter paper to prepare a portable paper-based ratio fluorescence sensor. By utilizing the specific boron affinity between the boric acid group in APBA and the cis-ortho-dihydroxy group in the oxytetracycline OTC molecule, the boric acid group and the cis-diol form a stable boron-oxygen ring ester structure, which enhances the selective recognition ability of the fluorescence sensor for OTC, reduces the influence of other interfering substances in complex water bodies (such as antibiotic pollutants, metal ions, etc.), and significantly improves the anti-interference performance of the detection system.

[0011] 2. This invention uses Whatman NO.1 filter paper as the substrate material, i.e., the carrier. Through the permeation and adsorption of cellulose in the filter paper, APBA-CsPbBr3@UiO-66 / Ru is fixed on the filter paper to construct a paper-based ratio fluorescence sensor. The porous structure of the filter paper provides a uniform loading platform for the APBA-CsPbBr3@UiO-66 / Ru composite material, ensuring stable fluorescence signal. At the same time, this paper-based carrier has the characteristics of low cost, lightweight, and portability. Only a small amount of fluorescent material is needed for detection, reducing the amount of lead-based perovskite quantum dots used, reducing potential environmental risks, and meeting the needs of on-site real-time detection.

[0012] 3. This invention captures fluorescence images of a portable paper-based ratio fluorescence sensor under 365nm ultraviolet light after loading OTC, and extracts the R / G value of the fluorescence colorimetry using ImageJ image processing software. A linear relationship between the R / G value and the OTC concentration is established (two linear ranges: 1.5μM~20μM and 20μM~45μM). Thus, the OTC concentration can be intuitively reflected through visual color changes (gradual change from green to red), avoiding the operational complexity and high cost limitations of traditional instrument analysis. Furthermore, the image analysis function of a smartphone is used to further improve the accuracy of detection, realizing the portable and real-time quantitative detection of OTC in water using a portable paper-based ratio fluorescence sensor.

[0013] 4. The optimized detection conditions for the portable paper-based ratio fluorescence sensor of this invention are pH=7 and response time of 8 min, which ensures that APBA-CsPbBr3@UiO-66 / Ru maintains stable fluorescence performance on the paper-based carrier. The neutral pH environment ensures the specific binding of the boric acid group in APBA to the cis-o-dihydroxy group in the oxytetracycline OTC molecule and the optical stability of the APBA-CsPbBr3@UiO-66 / Ru fluorescence sensor. The 8 min response time ensures that the fluorescence signal reaches equilibrium, making the sensor's detection limit for OTC as low as 0.63 μM, which meets the trace detection requirements of OTC residues in actual water bodies. At the same time, the spiked recovery experiment (recovery rate 98.27%~102.01%) verifies its reliability in practical applications.

[0014] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0015] Figure 1 The fluorescence intensity and relative quenching amount of different concentrations of OTC for APBA-CsPbBr3@UiO-66 prepared with different APBA molar modification ratios are shown.

[0016] Figure 2 The microstructure and elemental distribution diagram of the portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in Example 4 of this invention are shown.

[0017] Figure 3 The image shows the fluorescence image and the percentage of fluorescence chromaticity G values ​​of the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in Example 4 of this invention.

[0018] Figure 4 The image shows the fluorescence image and fluorescence chromaticity effect of the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in Example 4 of this invention under different pH conditions.

[0019] Figure 5 The portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in Example 4 of this invention has fluorescence images and R / G values ​​of fluorescence chromaticity at different times after adding OTC solution.

[0020] Figure 6 Fluorescence images and linear fitting plots of the portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in Example 4 of this invention at different OTC concentrations.

[0021] Figure 7Fluorescence images and bar graphs of the portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in Example 4 of this invention, showing its resistance to antibiotic pollutants and metal ions. Detailed Implementation Example

[0022] The portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru of this embodiment is prepared from the following components: cesium bromide, lead bromide, N,N-dimethylformamide, 5-bromopentanoic acid, oleylamine, perfluorooctyltriethyloxysilane, zirconium chloride, terephthalic acid, ethanol, methyl acetate, ruthenium tri(2,2-bipyridine)chloride hexahydrate, and Whatman NO.1 filter paper; The preparation method includes the following steps: Step 1: Add 0.4 mmol lead bromide and 0.4 mmol cesium bromide to N,N-dimethylformamide and stir continuously for 30 min until completely dissolved. Then add 0.764 g of 5-bromopentanoic acid and 0.6 mL of oleylamine ligand in sequence, and continue stirring at room temperature for 15 min to allow the ligand to react fully and obtain a mixed solution. Step 2: Add 300 μL of perfluorooctyltriethyloxysilane to the mixed solution obtained in Step 1 and stir for 20 min to obtain the CsPbBr3PQDs precursor solution. Step 3: Add 0.2330g of zirconium chloride and 0.1661g of terephthalic acid to 20mL of N,N-dimethylformamide and sonicate for 20min to obtain a homogeneous solution; Step 4: Transfer the homogeneous solution obtained in Step 3 to a 50 mL reactor lined with polytetrafluoroethylene, and heat the reactor at 120 °C for 24 h. After the reaction is completed, allow the reaction system to cool naturally to room temperature to obtain a precipitate. Then, wash the precipitate with N,N-dimethylformamide and ethanol in sequence. Dry the washed precipitate under vacuum at 60 °C for 12 h to obtain zirconium-based MOF, i.e., UiO-66. Step 5: Slowly add the CsPbBr3PQDs precursor solution obtained in Step 2 to methyl acetate, and add 0.1487 g of APBA and stir for 3 h in the dark to obtain APBA-CsPbBr3PQDs. Then, add 0.1 g of UiO-66 from Step 4 at room temperature and continue stirring for 2 h to form APBA-CsPbBr3@UiO-66. Then, add 0.075 g of tris(2,2-bipyridine)chloride hexahydrate and stir for 1 h. Filter the precipitate and wash it with methyl acetate. Dry it under vacuum at 60 °C for 6 h to obtain the APBA-CsPbBr3@UiO-66 / Ru composite material. Step 6: Cut the Whatman NO.1 filter paper to a length × width of 1.5cm × 1.5cm, drop a solution of APBA-CsPbBr3@UiO-66 / Ru composite material from Step 5 onto the surface, and air dry at room temperature to obtain the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru. Example

[0023] The difference between this embodiment and Embodiment 1 is that 5-bromopentanoic acid is not added in step one, and 0.05g of UiO-66 is added in step five. Example

[0024] The difference between this embodiment and Embodiment 1 is that 0.181g of 5-bromopentanoic acid is added in step one, and 0.08g of UiO-66 is added in step five. Example

[0025] The difference between this embodiment and Embodiment 1 is that 0.362g of 5-bromopentanoic acid is added in step one. Example

[0026] The difference between this embodiment and Embodiment 1 is that 0.362g of 5-bromopentanoic acid is added in step one, but oleylamine ligand is not added, and 0.12g of UiO-66 is added in step five. Example

[0027] The difference between this embodiment and Embodiment 1 is that 0.362g of 5-bromopentanoic acid is added in step one, and 0.15g of UiO-66 is added in step five. Example

[0028] The difference between this embodiment and Embodiment 1 is that 0.362g of 5-bromopentanoic acid is added in step one, and 0.2g of UiO-66 is added in step five.

[0029] The portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in this invention was analyzed and detected.

[0030] Based on the preparation method of Example 4, APBA-CsPbBr3@UiO-66 was prepared by using different APBA molar modification ratios, and the effects of different APBA molar modification ratios (i.e., the molar ratio of APBA to CsPbBr3PQDs) were investigated. Figure 1 The fluorescence intensity of CsPbBr3@UiO-66 under PQDs (abbreviated as PQDs) and the relative quenching of OTC at different concentrations (1.0 μM, 5.0 μM, 10 μM) are shown in the figure. Figure 1 As shown.

[0031] from Figure 1 Figure (a) shows the fluorescence intensity of APBA-CsPbBr3@UiO-66 prepared with different APBA molar modification ratios. It can be seen that as the amount of APBA modification gradually increases, the fluorescence intensity of CsPbBr3@UiO-66 increases slightly. The fluorescence intensity of CsPbBr3@UiO-66 reaches its maximum value when the APBA molar modification ratio is 1:1, indicating the highest detection sensitivity at this point. Figure 1 Figure (b) shows the relative quenching effect of APBA-CsPbBr3@UiO-66 prepared with different APBA molar modification ratios on different concentrations of OTC. It can be seen that when the APBA molar modification ratio is 1:1, CsPbBr3@UiO-66 has a good quenching effect on different concentrations of OTC and the best fluorescence response.

[0032] Therefore, in order to balance the optical performance of the quantum dot fluorescence sensor and the detection effect on OTC, the present invention selects the optimal molar modification ratio of APBA as 1:1.

[0033] The microstructure of the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in Example 4 of this invention was observed using a scanning electron microscope, and its corresponding elemental distribution map was obtained. The results are shown in the figure.

[0034] from Figure 2 The microstructure of the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru in Figure (a) shows that the filter paper substrate material of the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru has uniform fibers and a smooth surface. Uniformly dispersed octahedral crystals are grown on the fiber surface. APBA-CsPbBr3@UiO-66 / Ru is attached to the surface of the paper fiber structure and fills the gaps in the paper fiber structure (left figure). Under high magnification, obvious protrusions can be seen (right figure), which proves that APBA-CsPbBr3@UiO-66 / Ru is successfully fixed on the surface of the paper substrate material.

[0035] from Figure 2 Figure (b) shows the elemental distribution of the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru. It can be seen that the Pb, Cs, Br, Zr, and Ru elements in the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru are uniformly distributed on the paper-based material.

[0036] To ensure the reliability of the paper-based sensor during the detection process, the stability of the fluorescence colorimetry of the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in Example 4 of this invention within 1 hour was investigated through a colorimetric-time stability experiment. The results are as follows: Figure 3 As shown.

[0037] from Figure 3 As shown in Figure (a) of the fluorescence image and Figure (b) of the proportion of fluorescence chromaticity G values, the proportion of chromaticity G values ​​of the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru remains basically unchanged within 60 minutes, and the fluorescence image within 60 minutes exhibits uniform bright green fluorescence. This indicates that the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in this invention can maintain its original fluorescence characteristics and has good chromaticity stability, effectively ensuring the accuracy and reliability of the colorimetric detection system. Therefore, the APBA-CsPbBr3@UiO-66 / Ru paper-based sensor constructed in this invention can serve as an efficient on-site detection platform for subsequent aqueous OTC tests.

[0038] (4) Optimal detection pH value The acidity or alkalinity of the solution can affect the fluorescence performance of the fluorescence sensor to a certain extent, which in turn affects the accuracy of the APBA-CsPbBr3@UiO-66 / Ru paper-based sensor colorimetric detection system. The detection results of the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in Example 4 of this invention under different pH conditions were analyzed, and the results are as follows: Figure 4 As shown.

[0039] from Figure 4 Figure (a) shows fluorescence images under different pH conditions and Figure 4 (b) The effect of different pH conditions on fluorescence chromaticity shows that the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru has the largest proportion of fluorescence chromaticity G value at pH=7, and its fluorescence image has the deepest green light under ultraviolet light. As the solution pH gradually decreases, the proportion of fluorescence chromaticity G value gradually decreases, and the green fluorescence of the fluorescence image gradually becomes lighter. When the pH value approaches the alkaline range, as the alkaline range increases, the proportion of fluorescence chromaticity G value decreases slightly, and the color of the fluorescence image also becomes lighter. This indicates that acidic or alkaline environments can affect the colorimetric detection performance of the sensor to some extent.

[0040] To ensure the accuracy of subsequent detection by the paper-based fluorescence sensor, this invention selects pH=7 as the optimal detection pH value for the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru.

[0041] The detection results of the portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in Example 4 of this invention at different time points after adding OTC solution (concentration 30 μM) were analyzed. The results are as follows: Figure 5 As shown.

[0042] from Figure 5 The fluorescence image in the middle (a) and Figure 5 As shown in Figure (b) of the fluorescence colorimetric R / G value, as time progresses, the R / G value of the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru reacts with the OTC solution. After 3 minutes, the fluorescence colorimetric value of the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru shows a significant color difference change. After 8 minutes, it exhibits obvious red fluorescence, and the fluorescence colorimetric value basically stabilizes after 8 minutes, which is consistent with the trend of R / G value change measured by the colorimetric analysis software ImageJ.

[0043] Therefore, this invention selects 8 minutes as the optimal detection time for the APBA-CsPbBr3@UiO-66 / Ru paper-based sensor to detect OTC.

[0044] The fluorescence and colorimetric characteristics of the portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in Example 4 of this invention were investigated experimentally to evaluate its visualization detection effect on OTC. The results are as follows: Figure 6 As shown.

[0045] from Figure 6 As shown in the fluorescence chromaticity diagram in Figure (a), with the increase of OTC concentration, the fluorescence chromaticity of the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru gradually changes from green to red. This is because the degree of green fluorescence quenching of the APBA-CsPbBr3@UiO-66 composite material increases with the increase of OTC concentration, while the red fluorescence of Ru remains basically stable. Therefore, the green fluorescence of the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru fluorescence image will gradually become lighter. When the green fluorescence is quenched to a certain extent, its fluorescence color will gradually change from light green to red.

[0046] from Figure 6Figure (b) shows the linear fitting plot, which reveals the linear response relationship between the fluorescence chromaticity R / G value and OTC concentration of the portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru. Within the OTC concentration ranges of 1.5 μM to 20 μM and 20 μM to 45 μM, the R / G value of the fluorescence chromaticity of the portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru exhibits a good linear response relationship with OTC, with fitting equations of R / G = 0.0292C. OTC +0.1104, R / G=0.15557C OTC -2.6383, correlation coefficient R 2 The values ​​were 0.9853 and 0.9994, respectively, with a detection limit of 0.63 μM.

[0047] Based on the colorimetric sensing analysis of OTC by the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in Example 4 of this invention (6), the anti-interference performance of the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru for OTC detection was further studied. This experiment selected typical antibiotic contaminants (sulfadiazine SD, ampicillin AM, corrosive acid HA, sulfamethoxazole SMZ, sulfamethoxazole SMR) and common metal ions (Ag). + Mg 2+ Ca 2+ Al 3+ As an anti-interference material, 30 μM OTC and 100 μM of other contaminants were added to the paper-based sensor, respectively. Fluorescence images of the paper-based sensor were captured using a smartphone, and their RGB values ​​were further analyzed. The results are as follows: Figure 7 As shown.

[0048] from Figure 7 As shown in Figure (a) (fluorescence image) and Figure (b) (bar chart), the fluorescence chromaticity of the portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru remained almost unchanged before and after the addition of other pollutants. The ratio of the initial chromaticity value G0 before addition to the chromaticity value G after addition, G0% / G%, remained essentially unchanged. However, after adding OTC to the portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru, its fluorescence chromaticity changed from green to red, its hue changed significantly, the proportion of G value decreased significantly, and G0% / G% increased significantly. The experimental results show that the portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru of the present invention has good anti-interference characteristics.

[0049] The portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in Example 4 of this invention was applied to the detection of OTC in actual water bodies to examine its practical application capability. In this experiment, OTC standard solutions of different concentrations were added to the portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru (samples 1-6) prepared in Example 4. Fluorescence images were obtained by taking pictures with a smartphone. The R / G values ​​of the fluorescence images were substituted into the fitted linear equation in (6) to calculate the concentration of OTC in the water sample. The results are shown in Table 1 below:

[0050] As shown in Table 1, the portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru exhibits spiked recoveries of 98.27%–102.01% for OTC, with relative standard deviations (RSDs) ranging from 2.6% to 7.0%. This indicates that the portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru prepared in this invention can serve as an effective method for rapid on-site detection of OTC in actual water bodies.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru, characterized in that, It is prepared from the following components: cesium bromide, lead bromide, N,N-dimethylformamide, 5-bromovalerate, oleylamine, perfluorooctyltriethyloxysilane, zirconium chloride, terephthalic acid, ethanol, methyl acetate, tri(2,2-bipyridine)chloride hexahydrate, and Whatman NO.1 filter paper; The preparation method includes the following steps: Step 1: Add lead bromide and cesium bromide to N,N-dimethylformamide and stir continuously until completely dissolved. Then, add 5-bromopentanoic acid and oleylamine ligand in sequence, and continue stirring at room temperature to allow the ligand to react fully and obtain a mixed solution. Step 2: Add perfluorooctyltriethyloxysilane to the mixed solution obtained in Step 1 and stir to obtain CsPbBr3PQDs precursor solution; Step 3: Add zirconium chloride and terephthalic acid to N,N-dimethylformamide and sonicate to obtain a homogeneous solution; Step 4: Transfer the homogeneous solution obtained in Step 3 to a reaction vessel lined with polytetrafluoroethylene, and heat the reaction vessel to carry out the reaction. After the reaction is completed, allow the reaction system to cool down to room temperature naturally to obtain a precipitate. Then, wash the precipitate with N,N-dimethylformamide and ethanol in sequence, and after vacuum drying, obtain zirconium-based MOF, i.e., UiO-66. Step 5: Slowly add the CsPbBr3PQDs precursor solution obtained in Step 2 to methyl acetate, and add APBA while stirring in the dark to obtain APBA-CsPbBr3PQDs. Then, add UiO-66 from Step 4 at room temperature and continue stirring to form APBA-CsPbBr3@UiO-66. Then, add ruthenium tris(2,2-bipyridine)chloride hexahydrate and stir. Filter the precipitate and wash it with methyl acetate. After vacuum drying, obtain the APBA-CsPbBr3@UiO-66 / Ru composite material. Step 6: After cutting the Whatman NO.1 filter paper, drop the solution of APBA-CsPbBr3@UiO-66 / Ru composite material from Step 5 onto the surface, and let it air dry at room temperature to obtain the portable paper-based ratio fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru.

2. The method for preparing a portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru according to claim 1, characterized in that, In step one, the molar ratio of lead bromide to cesium bromide is 1:1, and the molar ratio of 5-bromopentanoic acid to oleylamine ligand is 1:1, 2:1, 0:1, 0.5:1, or 1:

0.

3. The method for preparing a portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru according to claim 1, characterized in that, The ratio of zirconium chloride, terephthalic acid, and N,N-dimethylformamide used in step three is 0.2330g:0.1661g:20mL.

4. The method for preparing a portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru according to claim 1, characterized in that, In step five, the amount of UiO-66 added is 0%, 34.1%, 54.5%, 68.1%, 81.7%, and 102.2% of the mass of lead bromide. The ratio of APBA to tris(2,2-bipyridine)chloride hexahydrate is 0.1487 g: 0.075 g, and the molar ratio of APBA to CsPbBr3PQDs is 1:

1.

5. The method for preparing a portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru according to claim 1, characterized in that, In step one, the continuous stirring time is 20-40 minutes, and the further stirring time is 10-20 minutes; in step two, the stirring time is 10-30 minutes; in step three, the ultrasonic treatment time is 10-30 minutes; in step four, the heating temperature is 120°C, the reaction time is 24 hours, and the vacuum drying temperature is 60°C for 10-14 hours; in step five, the light-protected stirring time is 2-4 hours, the addition of UiO-66 and continued stirring time is 2 hours, the addition of tris(2,2-bipyridine)chloride hexahydrate and stirring time is 1 hour, and the vacuum drying temperature is 60°C for 4-8 hours.

6. The method for preparing a portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3@UiO-66 / Ru according to claim 1, characterized in that, In step six, cut the Whatman NO.1 filter paper to a length × width of 1.5cm × 1.5cm, and drop a solution of APBA-CsPbBr3@UiO-66 / Ru composite material at a concentration of 1.5mg / mL onto the surface.

Images