O-probe carbon quantum dot fluorescent probe as well as preparation method and application thereof

Abstract

The invention relates to the technical field of fluorescent probes, and provides an O-probe carbon quantum dot fluorescent probe as well as a preparation method and application thereof in order to solve the problems of insufficient synthesis, stability, environmental adaptability and selectivity of an organic small molecule fluorescent probe in the prior art. The preparation method comprises the following steps: by taking rhodamine B and dimethylaminothioformyl chloride as raw materials, adding absolute ethyl alcohol, carrying out ultrasonic dissolution to obtain a mixed solution, carrying out heating reaction in a high-pressure kettle, carrying out column chromatography separation, collecting the obtained liquid with orange fluorescence, and carrying out rotary evaporation to finally obtain the O-probe carbon quantum dot fluorescent probe. The O-probe carbon quantum dot fluorescent probe has good selectivity on HClO, and the fluorescent probe with remarkable color change before and after responding to HClO is also widely applied to an anti-counterfeiting technology. In the anti-counterfeiting technology, the O-probe carbon quantum dot fluorescent probe and the multi-color CQDs are combined and applied to manufacturing of the textile anti-counterfeiting two-dimensional code, the fluorescence characteristic of the carbon quantum dots is fully utilized, and anti-counterfeiting is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of fluorescent probes, and in particular to an O-probe carbon quantum dot fluorescent probe and a preparation method and application thereof. Background Art

[0002] In the tide of globalization, textiles, as an important part of daily life, have received unprecedented attention for their quality and safety. Hypochlorous acid (HClO), as a widely used bleaching agent, plays a key role in improving the appearance and durability of textiles. However, excessive use of hypochlorous acid not only poses a potential threat to the environment, but may also have adverse effects on human health. In addition, the problem of counterfeiting and shoddy products in the textile market is becoming increasingly serious, causing serious damage to brand reputation and consumer rights. Therefore, the development of a new fluorescent probe that can accurately detect hypochlorous acid and has information anti-counterfeiting function is of great significance to ensure the safety and authenticity of textiles. Summary of the invention

[0003] Fluorescent probe technology has been widely used in chemical analysis and biomedicine due to its high sensitivity, high selectivity and real-time monitoring capabilities. Although traditional small molecule fluorescent probes perform well in some applications, they have limitations in stability, photostability and environmental adaptability. In recent years, carbon-based nanomaterial fluorescent probes have gradually become a research hotspot due to their unique physicochemical properties, such as large Stokes shift, low background interference, high quantum yield, good thermal and chemical stability, and easy surface modification.

[0004] Carbon-based nanomaterials, such as carbon dots (CDs), carbon nanofibers, fullerenes, carbon nanotubes, and graphene quantum dots, show great potential in the field of fluorescent probes due to their excellent optical properties and chemical stability. These materials can achieve precise control of fluorescence emission wavelength, quantum yield, and fluorescence lifetime by changing their composition, structure, or surface modification. In addition, the surface of carbon-based nanomaterials is easy to modify, and specific recognition of specific biomolecules can be achieved through covalent bonding or non-covalent interactions.

[0005] In response to this existing problem, the existing announcement number is "CN107746406B", and the patent name is "Preparation and Application of an Ultra-Sensitive Highly Selective Hypochlorous Acid Fluorescent Probe". The probe is a type of fluorescein compound, which can be used as a hypochlorous acid fluorescent probe for the detection of hypochlorous acid. This type of probe can achieve at least one of the following technical effects: ultra-sensitive and highly selective identification of hypochlorous acid and accurate detection; can quickly respond to hypochlorous acid; can achieve instant detection of hypochlorous acid; stable in nature, can be stored for a long time; and is conducive to the detection of hypochlorous acid (in vivo / in vitro) in actual samples.

[0006] However, the prior art still has the following problems: 1. The stability and photostability of the organic small molecule fluorescent probe are insufficient. It is easy to photobleach or degrade under continuous illumination or complex environmental conditions, thereby weakening the fluorescence signal and affecting the accuracy and reliability of the detection results; 2. The production process of the organic small molecule fluorescent probe often involves complex multi-step synthesis and purification steps, resulting in high production costs; 3. The organic small molecule fluorescent probe has insufficient selectivity for the target analyte and is easily interfered by molecules with similar structures in the sample, increasing the risk of false positive or false negative results.

[0007] In order to comprehensively solve the above problems, the present invention aims to design a novel carbon quantum dot fluorescent probe for monitoring the concentration of hypochlorous acid during the bleaching process of fabrics and apply it to information anti-counterfeiting technology.

[0008] Therefore, the present invention successfully synthesized a fluorescent probe (O-probe) using dimethylaminothiocarbonyl chloride and rhodamine B as precursors. The probe has good selectivity for HClO, and fluorescent probes with significant color changes before and after responding to HClO are also widely used to combat information forgery. In anti-counterfeiting technology, CQDs of various colors are prepared by precisely controlling the synthesis conditions. These CQDs have excellent fluorescence properties and stability and are very suitable for anti-counterfeiting technology. These multi-color CQDs are further applied to the production of textile anti-counterfeiting QR codes, making full use of the fluorescence properties of carbon quantum dots.

[0009] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides an O-probe carbon quantum dot fluorescent probe, which uses rhodamine B and dimethylaminothiocarbonyl chloride as raw materials, adds anhydrous ethanol, and ultrasonically dissolves to obtain a mixed solution. After heating reaction in an autoclave, it is separated by column chromatography, and the obtained liquid with orange fluorescence is collected and rotary evaporated to obtain an O-probe fluorescent probe.

[0010] The second aspect of the present invention provides a method for preparing an O-probe carbon quantum dot fluorescent probe, comprising: Step 1: Place rhodamine B and dimethylaminothiocarbonyl chloride in a beaker, then add anhydrous ethanol and perform ultrasound to fully dissolve the sample to obtain a mixed solution; Step 2: Transfer the mixed solution of step 1 to a stainless steel autoclave, place the autoclave in a vacuum drying oven for heat preservation, and then cool naturally to room temperature to obtain a crude product; Step 3: The crude product is separated by column chromatography, and the obtained liquid with orange fluorescence is collected and rotary evaporated to obtain the O-probe carbon quantum dot fluorescent probe.

[0011] Preferably, in step 1, the mass ratio of rhodamine B to dimethylaminothiocarbonyl chloride is 1.6:10.

[0012] Preferably, in step 2, the temperature of the vacuum drying oven is 180° C. and the insulation time is 12 h.

[0013] Preferably, the eluents for column chromatography separation in step 3 are methanol and dichloromethane, and the volume ratio of methanol to dichloromethane is 1:4.

[0014] The third aspect of the present invention provides a use of an O-probe carbon quantum dot fluorescent probe prepared as described above as a reagent for preparing HClO detection.

[0015] A fourth aspect of the present invention provides a use of an O-probe carbon quantum dot fluorescent probe prepared as described above as a safe dye.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The synthesis process of the carbon quantum dot nano fluorescent probe of the present invention is relatively simple. The present invention is to fully dissolve rhodamine B, dimethylaminothiocarbonyl chloride and anhydrous ethanol and then move them to the reactor (no need to add anything in the middle), use a vacuum drying oven for 12 hours, and keep warm at 180°C; while the prior art is to dissolve fluorescein and dimethylaminothiocarbonyl chloride in dichloromethane and add diisopropylethylamine to stir at room temperature (25°C) for 20 hours. The present invention is a one-step operation in terms of steps. It can be started after the sample is dissolved, and nothing needs to be added in the middle, and the reaction time is only 12 hours; while the comparative document needs to add diisopropylethylamine after the sample is dissolved, and the reaction time is 20 hours.

[0017] In addition, in terms of raw materials, the present invention uses rhodamine B, dimethylaminothiocarbonyl chloride and anhydrous ethanol, while the prior art uses fluorescein, dimethylaminothiocarbonyl chloride, dichloromethane and diisopropylethylamine. The raw materials used in the present invention and the prior art are different, and the raw materials in the prior art are more diverse and more expensive.

[0018] Therefore, the technical solution of the present invention is easy to mass produce, thereby significantly reducing production costs, saving raw materials and resources, and facilitating popularization and application.

[0019] 2. In terms of preparation method, the rhodamine of the present invention and the fluorescein of the prior art are two fundamentally different substances and do not belong to the same type of fluorescein compounds. The present invention is a carbon quantum dot nanofluorescent probe, while the prior art is an organic small molecule material.

[0020] 3. The carbon quantum dot nano fluorescent probe of the present invention is a nano material with good stability and photostability. First, these carbon atoms form stable carbon-carbon bonds through sp² hybridization, have high chemical inertness, and are not easy to react chemically with other substances. The optical properties of carbon quantum dots are usually more stable. The whole is composed of carbon atoms and is not easily affected by environmental factors. Therefore, it is not easy to photobleach or degrade under continuous illumination or complex environmental conditions. Secondly, carbon quantum dots have a large specific surface area and abundant surface functional groups, which enables them to provide more reaction sites, thereby enhancing the interaction with the target molecules.

[0021] The reference documents are organic small molecule materials. The selectivity of organic small molecules usually depends on the design of their molecular structure and functional groups. Organic small molecule materials usually contain multiple functional groups. Therefore, organic small molecules may cross-react with other molecules in the environment, resulting in reduced selectivity and increased risk of false positive signals. These functional groups may react with other molecules, resulting in changes in molecular structure or decomposition.

[0022] 4. The carbon quantum dot nano fluorescent probe of the present invention has higher sensitivity and can accurately and efficiently detect HClO in the textile bleaching process. The high sensitivity of the carbon quantum dot nano fluorescent probe of the present invention mainly comes from its large specific surface area, which increases the chance of contact with the target molecule, thereby improving the sensitivity of detection. The specific surface area of ​​small organic molecules is relatively small, which limits the chance of contact with the target molecule. In addition, small organic molecules may undergo self-absorption or self-quenching at high concentrations. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0024] In the attached picture: Figure 1 In the figure, (a) UV-visible absorption spectrum of O-probe; (b) fluorescence emission spectrum of probe O-probe under different concentrations of HClO (0-100μM); (c) fluorescence images after adding different concentrations of HClO (10, 100, 200, 400, 800, 1000, 10000μM); Figure 2 In the figure, (a) the fluorescence image of the test paper soaked with the probe O-probe to detect HClO (10-10000μM) under sunlight; (b) the fluorescence image of the test paper soaked with the probe O-probe to detect HClO (10-10000μM) at 365nm; (c) the fluorescence image of the test paper soaked with the probe O-probe to detect before and after bleaching; Figure 3 It is a schematic diagram of the operation of the colorimetric fluorescence test strip of the present invention; Figure 4 It is a flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0025] The following combination Figure 1-Figure 4 The preferred embodiments of the present invention are described. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0026] Chemical reagents and instruments: Anhydrous ethanol was purchased from Hengxing Chemical Reagent Co., Ltd., rhodamine B, dimethylaminothiocarbonyl chloride, p-phenylenediamine, fluorescein, and ferric chloride were purchased from Aladdin Chemical Reagent Co., Ltd., and hypochlorous acid (with an effective chlorine content of 8%) was purchased from Aladdin Chemical Reagent Co., Ltd.

[0027] Their UV-visible absorption spectra were measured using a Shimadzu UV-2700 spectrophotometer, and the fluorescence data were measured on a Dongfeng Hitachi-7000 fluorescence / phosphorescence / luminescence spectrophotometer.

[0028] Embodiment 1: An O-probe carbon quantum dot fluorescent probe is provided. Rhodamine B and dimethylaminothiocarbonyl chloride are used as raw materials, anhydrous ethanol is added, and ultrasonic dissolution is performed to obtain a mixed liquid. After heating reaction in an autoclave, the mixed liquid is separated by column chromatography, and the obtained liquid with orange fluorescence is collected and rotary evaporated to obtain the O-probe carbon quantum dot fluorescent probe.

[0029] Embodiment 2: A method for preparing an O-probe carbon quantum dot fluorescent probe, comprising: Step 1: Place 0.016 g of rhodamine B and 0.1 g of dimethylaminothiocarbonyl chloride in a beaker, then add 15 mL of anhydrous ethanol and sonicate for 10 min to fully dissolve the sample to obtain a mixed solution; Step 2: Transfer the mixed solution of step 1 into a 20 mL stainless steel autoclave (lined with polytetrafluoroethylene), place the autoclave in a 180 °C vacuum drying oven for 12 h, and then cool naturally to room temperature to obtain a crude product; Step 3: The crude product was separated by column chromatography, and the obtained liquid with orange fluorescence was collected and rotary evaporated at 50° C. to obtain the O-probe carbon quantum dot fluorescent probe. The eluents for column chromatography separation were methanol and dichloromethane, and the volume ratio of methanol to dichloromethane was 1:4.

[0030] Embodiment 3: For example, the O-probe carbon quantum dot fluorescent probe in Example 1 is used as a reagent for preparing HClO detection.

[0031] Determination of hypochlorous acid content: Cut the filter paper into The test strip was then immersed in a probe solution with a concentration of 2.78 μg / ml for 5 s and allowed to dry naturally. Next, different concentrations of HClO solution (10-10000 μM) were prepared at room temperature and dripped onto the test strip in turn, and the fluorescence changes of the test strip were recorded with the naked eye under ultraviolet light.

[0032] To determine the HClO content in the bleached samples, according to the corporate standard for chlorine bleach (effective chlorine content ≥ 1.5%), a white cotton lining cloth was cut into a circle with a diameter of 6 cm. We used HClO (1000 μM) for bleaching and used a test paper to test the concentration change of the hypochlorous acid solution before and after bleaching. Fluorescence images were captured using a smartphone under the illumination of a portable UV lamp (365 nm).

[0033] The prepared O-probe carbon quantum dot fluorescent probe was dissolved in anhydrous ethanol and the solution was diluted to 0.56 μg / ml.

[0034] When HClO (0-100 μM) was measured, 10 μL of HClO stock solution (100 μM) was added to each test tube in addition to the O-probe. The excitation wavelength for fluorescence measurement was 555 nm, and the emission wavelength range was 540 nm to 600 nm. The excitation and emission slit widths were 5 nm and 5 nm, respectively, and the PMT voltage was 700 V.

[0035] Embodiment 4: For example, the O-probe carbon quantum dot fluorescent probe of Example 1 is used to prepare a safe dye. The specific application method is: S1: Preparation of B-CQDs: 0.1 g of p-phenylenediamine, 0.05 g of ferric chloride and 0.1 g of dimethylaminothiocarbonyl chloride were placed in a beaker, and then 15 mL of anhydrous ethanol was added and ultrasonicated for 10 min to fully dissolve the sample; the mixed solution was transferred to a 20 mL stainless steel high-pressure reactor lined with polytetrafluoroethylene, and the autoclave was placed in a vacuum drying oven at 180°C and maintained at this temperature for 12 h, and then naturally cooled to room temperature to obtain B-CQDs.

[0036] S2: Preparation of Y-CQDs: 0.05 g of fluorescein, 0.05 g of ferric chloride and 0.1 g of dimethylaminothiocarbonyl chloride were placed in a beaker, and then 15 mL of anhydrous ethanol was added and ultrasonicated for 10 min to fully dissolve the sample; the mixed solution was transferred to a 20 mL stainless steel high-pressure reactor lined with polytetrafluoroethylene, and the autoclave was placed in a vacuum drying oven at 180 °C and maintained at this temperature for 12 h, and then naturally cooled to room temperature to obtain Y-CQDs.

[0037] S3: Preparation of safe dyes: Take 100 μL of the Y-CQDs carbon dots and O-probe carbon quantum dot fluorescent probes prepared above and dissolve them in 10 g of deionized water to prepare an aqueous solution; take 1 mL of the B-CQDs carbon dots prepared above and dissolve them in 10 g of deionized water to prepare an aqueous solution, then mix the prepared aqueous solution and propylene glycol in a volume ratio of 5:1, stir and disperse evenly, and prepare a combined liquid to obtain a carbon quantum dot fluorescent anti-counterfeiting ink.

[0038] Result analysis: 1. Detection performance and mechanism of O-probe carbon quantum dot fluorescent probe for HClO: Prepare test solutions containing O-probe carbon quantum dot fluorescent probe (2.78 μg / ml) and different concentrations of HClO, and measure the corresponding fluorescence and UV-visible absorption spectra. The results are as follows: Figure 1 As shown in (a) and (b). As the concentration of HClO increases from 0 μM to 100 μM, the fluorescence intensity of O-probe gradually increases. In addition, the fluorescence of O-probe solution with different concentrations of HClO was further studied. Figure 1 As shown in (c), as the concentration of HClO gradually increases, the fluorescence of the solution is observed to gradually increase. The above experimental results demonstrate the sensitivity and excellent selectivity of O-probe for HClO detection.

[0039] 2. Test strips: like Figure 3 FIG. 2 is a schematic diagram showing the operation of the colorimetric fluorescence test strip of the present invention.

[0040] As shown in Figure 2 (a), the test strip appears orange-pink under ultraviolet light. After spraying a certain amount of HClO solution, the color of the test strip changes.

[0041] Use test paper to test the concentration change of hypochlorous acid solution before and after bleaching. Figure 2 Figure 2 (b) shows the fluorescence image of the test paper impregnated with the probe O-probe before and after bleaching.

[0042] The results showed that the test strip was easy to carry and had sensitive detection ability, and could be used for semi-quantitative detection of changes in hypochlorous acid concentration before and after bleaching fabrics.

[0043] 3. QR code: In order to achieve multiple anti-counterfeiting properties for textiles, a variety of anti-counterfeiting QR codes with different invisible effects were prepared using O-probe solution as the main security dye, HClO solution spray as the identification agent, and carbon dots B-CQDs and Y-CQDs as secondary dyes, achieving a triple anti-counterfeiting effect. This QR code can not only effectively prevent textiles from being counterfeited and imitated, but also provide a convenient way to verify the authenticity of the product.

[0044] First, the two-dimensional code prepared by the present invention cannot be correctly scanned and recognized under ordinary sunlight. Only when it is irradiated with ultraviolet light can it be displayed and correctly read by the scanning device. Secondly, the two-dimensional code is jointly depicted by O-probe, B-CQDs and Y-CQDs, and different colors can be presented under ultraviolet light. Finally, different concentrations of HClO also cause different color changes on O-probe (such as Figure 2 In this way, triple protection of the pattern is achieved, enhancing the anti-counterfeiting effect.

[0045] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An O-probe carbon quantum dot fluorescent probe, characterized in that: Rhodamine B and dimethylaminothiocarbonyl chloride are used as raw materials, anhydrous ethanol is added, and ultrasonic dissolution is performed to obtain a mixed solution. After heating reaction in an autoclave, the mixed solution is separated by column chromatography, and the obtained liquid with orange fluorescence is collected and rotary evaporated to obtain an O-probe carbon quantum dot fluorescent probe.

2. A method for preparing an O-probe carbon quantum dot fluorescent probe, characterized in that: include: Step 1: Place rhodamine B and dimethylaminothiocarbonyl chloride in a beaker, then add anhydrous ethanol and perform ultrasound to fully dissolve the sample to obtain a mixed solution; Step 2: Transfer the mixed solution of step 1 to a stainless steel autoclave, place the autoclave in a vacuum drying oven for heat preservation, and then cool naturally to room temperature to obtain a crude product; Step 3: The crude product is separated by column chromatography, and the obtained liquid with orange fluorescence is collected and rotary evaporated to obtain the O-probe carbon quantum dot fluorescent probe.

3. The method for preparing an O-probe carbon quantum dot fluorescent probe according to claim 2, characterized in that: In step 1, the mass ratio of rhodamine B to dimethylaminothiocarbonyl chloride is 1.6:

10.

4. The method for preparing an O-probe carbon quantum dot fluorescent probe according to claim 3, characterized in that: In step 2, the temperature of the vacuum drying oven is 180°C and the insulation time is 12 h.

5. The method for preparing an O-probe carbon quantum dot fluorescent probe according to claim 4, characterized in that: The eluents for column chromatography separation in step 3 are methanol and dichloromethane, and the volume ratio of methanol to dichloromethane is 1:

4.

6. The use of an O-probe carbon quantum dot fluorescent probe as claimed in claim 1, characterized in that: Used as a reagent for preparing HClO detection.

7. The use of an O-probe carbon quantum dot fluorescent probe as claimed in claim 1, characterized in that: Used as a safe dye.

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