A method and probe for detecting ascorbic acid based on dye-sensitized upconversion

Abstract

The present invention discloses a method and probe for detecting ascorbic acid based on dye-sensitized upconversion. The method comprises: compounding an organic dye with rare earth-doped upconversion nanoparticles in an organic solvent with a low dielectric constant to obtain a dye-sensitized upconversion nanoparticle dispersion of a specific concentration; adding triethylamine to the dye-sensitized upconversion nanoparticle dispersion to obtain an upconversion system; mixing the upconversion system with a sample to be tested containing ascorbic acid, testing the luminescence intensity of the upconversion system, and realizing the detection of ascorbic acid. The method for detecting ascorbic acid provided by the present invention does not require chemical structure modification of the dye, and does not require further special treatment. High selectivity / high sensitivity and rapid detection of ascorbic acid are achieved through a simple, mild and low-cost method. The present invention provides a new method for designing highly selective and sensitive biological probes, and has broad application prospects in the field of biological molecule detection.

Description

Technical Field

[0001] The invention relates to a method for detecting ascorbic acid, in particular to a method for detecting ascorbic acid based on dye-sensitized up-conversion and a corresponding probe, belonging to the technical field of up-conversion biomolecule probes and detection. Background Art

[0002] Ascorbic acid, also known as vitamin C, is an essential vitamin in the human metabolism process. It helps to effectively utilize folic acid, calcium and iron and promotes the metabolism of fats and lipids. When the concentration of ascorbic acid in the human body is low, it will cause bleeding in the skin and submucosal membranes, joint pain and gingival swelling; when the concentration of ascorbic acid in the human body is high, it will cause diseases such as urinary stones, gastric cramps and diarrhea. Since the human body cannot produce ascorbic acid by itself and needs to obtain it through food intake, it is of great significance to develop a probe and method for rapid and sensitive detection of ascorbic acid. At present, many methods for the determination of ascorbic acid have been developed, including high performance liquid chromatography, spectrophotometry, electrochemical method, solid phase microextraction and LC-UC diode array method. Among them, the fluorescence method has attracted much attention due to its advantages such as good reproducibility and short detection time. However, the common fluorescence detection method based on organic dyes also has some inherent defects, such as easy photobleaching, low sensitivity, poor membrane permeability, etc. Summary of the invention

[0003] The main purpose of the present invention is to provide a method and probe for detecting ascorbic acid based on dye-sensitized upconversion, which realizes the identification and detection of ascorbic acid through a simple, mild and low-cost method to overcome the shortcomings of the prior art.

[0004] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0005] The embodiment of the present invention provides a method for detecting ascorbic acid based on dye-sensitized upconversion, which comprises:

[0006] Compounding an organic dye with rare earth-doped upconversion nanoparticles in an organic solvent with a low dielectric constant to prepare a dye-sensitized upconversion nanoparticle dispersion of a specific concentration;

[0007] adding triethylamine to the dye-sensitized upconversion nanoparticle dispersion to obtain an upconversion system;

[0008] The up-conversion system is mixed with a sample to be tested containing ascorbic acid, and the luminescence intensity of the up-conversion system is tested to achieve the detection of ascorbic acid.

[0009] Furthermore, the method comprises: adding a sample to be tested containing ascorbic acid to the up-conversion system, using triethylamine in the up-conversion system to enhance the nucleophilicity of ascorbic acid to cause luminescence quenching of the up-conversion system, thereby realizing the detection of ascorbic acid.

[0010] Furthermore, the organic dye comprises a near-infrared dye having a sulfonate group capable of interacting with the rare-earth-doped up-conversion nanoparticles.

[0011] The embodiment of the present invention further provides a probe for detecting ascorbic acid based on dye-sensitized up-conversion, wherein the probe comprises dye-sensitized up-conversion nanoparticles prepared by combining an organic dye with rare-earth-doped up-conversion nanoparticles.

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] 1) The present invention utilizes the characteristic of triethylamine to enhance the nucleophilicity of ascorbic acid, resulting in quenching of the luminescence of the upconversion system, thereby realizing the detection of ascorbic acid. The method for detecting ascorbic acid based on dye-sensitized upconversion provided by the present invention does not require chemical structure modification of the dye, and does not require further special treatment. The detection of ascorbic acid can be realized by medium regulation;

[0014] 2) The dye-sensitized upconversion nanoprobe provided by the present invention has high selectivity and sensitivity to ascorbic acid. After the probe molecule binds to ascorbic acid, the upconversion fluorescence is quenched, and it is not interfered by conventional substances such as cysteine, histidine, glutamine, arginine, valine, lysine, glutamic acid, citric acid, sucrose and glucose, and the detection limit reaches 0.103 μM. The detection method of ascorbic acid provided by the present invention is simple and low in cost, and can achieve high selectivity, high sensitivity and rapid detection of ascorbic acid, providing a new method for designing highly selective and highly sensitive biological probes, and has broad application prospects in the field of biological molecule detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 This is a diagram showing the change in up-conversion luminescence with increasing ascorbic acid concentration in Example 1 of the present invention.

[0017] Figure 2 This is a diagram showing the relationship between ascorbic acid concentration and up-conversion luminescence in Example 1 of the present invention.

[0018] Figure 3 It is the standard curve diagram of ascorbic acid drawn in Example 1 of the present invention.

[0019] Figure 4 It is a schematic diagram of the anti-interference ability of identifying ascorbic acid in Example 1 of the present invention.

[0020] Figure 5 This is a diagram showing the changes in up-conversion luminescence as ascorbic acid is added in Example 2 of the present invention.

[0021] Figure 6 This is a graph showing the change in up-conversion luminescence when ascorbic acid is added without adding triethylamine in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0022] In view of the many defects of the prior art, the inventor of this case has proposed the technical solution of the present invention after long-term research and extensive practice. The technical solution, its implementation process and principle, etc. will be further explained as follows. However, it should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described in the following (embodiments) can be combined with each other to form a new or preferred technical solution. Due to space limitations, they will not be described one by one here.

[0023] Dye-sensitized rare earth upconversion nanoluminescent materials are a new generation of biological probe materials. Compared with traditional organic dyes and quantum dots, they have the characteristics of large anti-Stokes shift, little damage to biological tissues, and no background fluorescence, and have great application prospects in the field of biosensing.

[0024] As one aspect of the technical solution of the present invention, it relates to a probe for detecting ascorbic acid based on dye-sensitized up-conversion, wherein the probe comprises dye-sensitized up-conversion nanoparticles prepared by combining an organic dye with rare-earth-doped up-conversion nanoparticles.

[0025] As another aspect of the technical solution of the present invention, it involves a method for detecting ascorbic acid based on dye-sensitized upconversion, comprising:

[0026] Compounding an organic dye with rare earth-doped upconversion nanoparticles in an organic solvent with a low dielectric constant to prepare a dye-sensitized upconversion nanoparticle dispersion of a specific concentration;

[0027] adding triethylamine to the dye-sensitized upconversion nanoparticle dispersion to obtain an upconversion system;

[0028] The up-conversion system is mixed with a sample to be tested containing ascorbic acid, and the luminescence intensity of the up-conversion system is tested to achieve the detection of ascorbic acid.

[0029] In some preferred embodiments, the method specifically comprises: adding a sample to be tested containing ascorbic acid to the upconversion system, utilizing triethylamine in the upconversion system to enhance the nucleophilicity of ascorbic acid, resulting in luminescence quenching of the upconversion system, and realizing detection of ascorbic acid.

[0030] In some more preferred embodiments, the method specifically comprises:

[0031] Compounding an organic dye with rare earth-doped upconversion nanoparticles in an organic solvent to prepare a dye-sensitized upconversion nanoparticle dispersion of a specific concentration;

[0032] Adding triethylamine of a selected concentration to the dye-sensitized upconversion nanoparticle dispersion to obtain an upconversion system;

[0033] Ascorbic acid was added into the up-conversion system, and the luminescence intensity of the up-conversion system was tested.

[0034] In some preferred embodiments, the organic dye compounded on the surface of the rare earth-doped upconversion nanoparticles in the upconversion system is a near-infrared dye, wherein the near-infrared dye has a fixed-base sulfonate group that can interact with the rare earth-doped upconversion nanoparticles.

[0035] Further, the near infrared dye may include at least one of IR808, IR820, IR845 and ICG, but is not limited thereto.

[0036] In some preferred embodiments, the rare earth doped upconversion nanoparticles include β-NaYF4: 20% Yb 3+ ,20%Er 3+ and β-NaYF4:20%Yb 3+ ,20%Er 3+ @NaYF4:10%Nd 3+ / 10%Yb 3+ At least one of the following, but not limited to.

[0037] Further, the organic solvent includes heptanol, but is not limited thereto.

[0038] In some preferred embodiments, the concentration of the organic dye in the dye-sensitized upconversion nanoparticle dispersion is 0.1-4.0 μM, and the concentration of the rare earth-doped upconversion nanoparticles is 1-22 mg / mL.

[0039] In some preferred embodiments, the concentration of triethylamine in the up-conversion system is 0.5-53.28 mM.

[0040] In some preferred embodiments, the method specifically comprises:

[0041] A series of standard sample solutions containing ascorbic acid at different concentrations are prepared, the series of standard sample solutions containing ascorbic acid at different concentrations are mixed with an up-conversion system, the up-conversion luminescence intensity of the series of standard sample solutions containing ascorbic acid at different concentrations is tested, a concentration-dependent standard curve of ascorbic acid is plotted with the logarithm of the concentration of ascorbic acid in the standard sample solution as the abscissa and the corresponding up-conversion luminescence intensity as the ordinate, and the detection limit of ascorbic acid is calculated;

[0042] The up-conversion luminescence intensity of the sample solution containing ascorbic acid is detected and compared with the concentration-dependent standard curve of the ascorbic acid, so as to obtain the concentration of ascorbic acid in the sample solution to achieve the detection of ascorbic acid.

[0043] In some more preferred embodiments, the method for simultaneously detecting ascorbic acid further comprises: preparing ascorbic acid solutions of different concentrations, mixing the ascorbic acid solutions of different concentrations with a heptanol solution of a dye-sensitized up-conversion fluorescent probe, testing the up-conversion luminescence intensity of the ascorbic acid solutions of different concentrations, plotting the ascorbic acid concentration-dependent standard curve, and calculating the detection limit of the ascorbic acid in the solution.

[0044] The mechanism of action of the present invention mainly lies in: using the high concentration of triethylamine in the dye-sensitized up-conversion system heptanol solution to enhance the nucleophilicity of ascorbic acid, the binding force between the triethylamine and the up-conversion nanoparticles is stronger than the binding force between the sulfonate group in the near-infrared dye and the up-conversion nanoparticles, causing the near-infrared dye to fall off the nano surface, thereby quenching the up-conversion luminescence, and realizing the qualitative detection of ascorbic acid. The logarithm of the ascorbic acid concentration presents a linear relationship with the up-conversion luminescence at 540nm, and the linear regression curve is used to realize the quantitative detection of ascorbic acid.

[0045] The concentration-dependent standard curve of ascorbic acid is drawn with the logarithm of the concentration of ascorbic acid in the mixed solution as the abscissa and the corresponding up-conversion luminescence intensity as the ordinate.

[0046] Furthermore, the concentration of ascorbic acid in the standard sample solution containing ascorbic acid is 0 to 600 μM.

[0047] Furthermore, the concentration-dependent standard curve is plotted with the logarithm of the concentration of ascorbic acid in the mixed solution as the abscissa and the corresponding up-conversion luminescence intensity excited at 785 nm or 808 nm as the ordinate.

[0048] Furthermore, the concentration-dependent standard curve is drawn with the logarithm of the concentration of ascorbic acid in the mixed solution as the abscissa and the corresponding up-conversion luminescence intensity at 540 nm as the ordinate.

[0049] In some preferred embodiments, the method further comprises: first dispersing the dye-sensitized upconversion nanoparticles in an organic solvent to obtain a dye-sensitized upconversion nanoparticle dispersion of a specific concentration; adding triethylamine of a selected concentration to the dye-sensitized upconversion nanoparticle dispersion to obtain an upconversion system; adding ascorbic acid to the upconversion system to test the luminescence intensity of the upconversion system.

[0050] Among them, in some more specific embodiments, the method for detecting ascorbic acid based on dye-sensitized upconversion comprises the following steps:

[0051] Step 1: Dispersing the near-infrared dye-sensitized upconversion nanoparticles in an organic solution, and ultrasonicating for 10 minutes to fully disperse the dye-sensitized upconversion nanoparticles;

[0052] Step 2: gradually adding triethylamine to the dye-sensitized upconversion nanoparticles, testing the upconversion luminescence intensity, selecting the optimal triethylamine dosage, and obtaining an upconversion system for testing ascorbic acid;

[0053] Step 3: gradually adding ascorbic acid of different concentrations into the up-conversion system to test the up-conversion luminescence intensity;

[0054] Step 4, plotting a standard curve of the logarithmic value of ascorbic acid concentration and the up-conversion luminescence intensity at 540 nm;

[0055] Furthermore, in step 1, the organic solvent is heptanol, but is not limited thereto.

[0056] Furthermore, in step 1, the near-infrared dye is cyanine, but is not limited thereto.

[0057] Furthermore, in step 1, the near-infrared dye contains a fixed-base sulfonate group that interacts with the up-conversion nanoparticle.

[0058] In summary, the method provided by the present invention enhances the nucleophilicity of ascorbic acid by triethylamine, quenches upconversion luminescence, and realizes qualitative and quantitative detection of ascorbic acid. The fluorescent probe based on dye-sensitized upconversion provided by the present invention does not require chemical structure modification of the dye, and does not require further special treatment. The detection of ascorbic acid can be achieved through medium regulation. The detection method of ascorbic acid provided by the present invention is simple and low in cost, and can achieve high selectivity, high sensitivity and rapid detection of ascorbic acid, providing a new method for designing highly selective and highly sensitive biological probes, and has broad application prospects in the field of biological molecule detection.

[0059] The technical scheme of the present invention is further described in detail below in conjunction with several preferred embodiments and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present invention. The implementation conditions used in the following embodiments can be further adjusted according to actual needs, and the unspecified implementation conditions are usually the conditions in conventional experiments.

[0060] Example 1

[0061] The structural formula of the organic dye IR820 in this embodiment is as follows:

[0062]

[0063] In this embodiment, the rare earth doped up-conversion nanomaterial is β-NaYF4: 20% Yb 3+ ,20%Er 3+ .

[0064] In this embodiment, the method for detecting ascorbic acid based on dye-sensitized upconversion luminescence specifically includes the following steps:

[0065] Step 1: Ultrasonicate the organic dye (3.5 μM) and the surface-modified rare earth upconversion nanoparticles (1 mg / mL) in a heptanol solution for 10 min to fully compound and disperse the upconversion nanoparticles and the organic dye;

[0066] Step 2: gradually add triethylamine to the dye-sensitized upconversion nanoparticles, test the upconversion luminescence intensity, select the optimal triethylamine dosage (53.28 mM), and obtain the upconversion system for testing ascorbic acid;

[0067] Step 3: gradually add different concentrations of ascorbic acid (0-600 μM) to the up-conversion system to test the up-conversion luminescence intensity;

[0068] Step 4: Draw a standard curve of the logarithmic value of ascorbic acid concentration and the upconversion luminescence intensity at 540 nm.

[0069] Figure 1 Upconversion luminescence spectra of 3.5 μM dye and 1.0 mg / mL upconversion nanoparticles in a heptanol solution containing 53.28 mM triethylamine with the addition of 0, 5, 10, 15, 20, 25, 30, 40, 50, 75, 100, 150, 250, 300, 400, 500 and 600 μM ascorbic acid. Figure 1It can be seen that with the increase of ascorbic acid concentration, the upconversion luminescence spectrum under 808nm laser pumping shows a gradually decreasing trend. When the ascorbic acid concentration is 150μM, the upconversion luminescence intensity decreases by 5.2 times. With the further increase of ascorbic acid concentration, the decreasing trend of upconversion luminescence intensity weakens.

[0070] Figure 2 This is a graph showing the relationship between ascorbic acid concentration and upconversion luminescence intensity at 540 nm after adding different concentrations of ascorbic acid to a heptanol solution containing 53.28 mM triethylamine to 3.5 μM organic dye and 1.0 mg / mL upconversion nanoparticles. Figure 3 is a standard curve plotting the logarithmic value of ascorbic acid concentration versus the upconversion luminescence intensity at 540 nm. Figure 3 It can be seen that when the ascorbic acid concentration is between 10-150 μM, the logarithmic value of the concentration shows a good linear relationship with the upconversion luminescence intensity at 540 nm, and the linear regression equation is F = -5895log C AA +13925. According to 3σ / slope, the detection limit of ascorbic acid is 0.103μM.

[0071] Figure 4 The interference of cysteine, histidine, glutamine, arginine, valine, lysine, glutamic acid, citric acid, sucrose and glucose on the detection of ascorbic acid at 3.5 μM dye and 1.0 mg / mL upconversion nanoparticles in heptanol solution containing 53.28 mM triethylamine. Figure 4 It can be seen that when the concentration of the interfering species is the same as that of ascorbic acid, both are 500 μM, the interfering species has almost no effect on the upconversion luminescence, and only ascorbic acid quenches the upconversion luminescence, indicating that the dye-sensitized upconversion nanoprobe has high selectivity and sensitivity to ascorbic acid.

[0072] Example 2

[0073] The structural formula of the organic dye IR783 in this embodiment is as follows:

[0074]

[0075] In this embodiment, the rare earth doped up-conversion nanomaterial is β-NaYF4: 20% Yb 3+ ,20%Er 3+ @NaYF4:10%Nd 3+ / 10%Yb 3+ .

[0076] In this embodiment, the method for detecting ascorbic acid based on dye-sensitized upconversion luminescence specifically includes the following steps:

[0077] Step 1: Ultrasonicate the organic dye (2.5 μM) and the surface-modified rare earth upconversion nanoparticles (1 mg / mL) in a heptanol solution for 10 min to fully compound and disperse the upconversion nanoparticles and the organic dye;

[0078] Step 2: gradually add triethylamine to the dye-sensitized upconversion nanoparticles, test the upconversion luminescence intensity, select the optimal triethylamine dosage (50.0 mM), and obtain the upconversion system for testing ascorbic acid;

[0079] Step 3: gradually add different concentrations of ascorbic acid (0-400 μM) to the up-conversion system to test the up-conversion luminescence intensity;

[0080] Step 4: Draw a standard curve of the logarithmic value of ascorbic acid concentration and the upconversion luminescence intensity at 540 nm.

[0081] Figure 5 Upconversion luminescence spectra of 2.5 μM organic dye and 1.0 mg / mL upconversion nanoparticles in a heptanol solution containing 50.0 mM triethylamine with the addition of 0, 5, 10, 15, 20, 25, 30, 40, 50, 75, 100, 150, 250, 300 and 400 μM ascorbic acid. Figure 5 It can be seen that with the increase of ascorbic acid concentration, the up-conversion luminescence spectrum shows a gradually decreasing trend under 785nm laser pumping.

[0082] Example 3

[0083] The structural formula of the organic dye ICG in this embodiment is as follows:

[0084]

[0085] In this embodiment, the rare earth doped up-conversion nanomaterial is β-NaYF4: 20% Yb 3+ ,20%Er 3+ @NaYF4:10%Nd 3+ / 10%Yb 3+ .

[0086] In this embodiment, the method for detecting ascorbic acid based on dye-sensitized upconversion luminescence specifically includes the following steps:

[0087] Step 1: Ultrasonicate the organic dye (0.1 μM) and the surface-modified rare earth upconversion nanoparticles (22 mg / mL) in a heptanol solution for 10 min to fully compound and disperse the upconversion nanoparticles and the organic dye;

[0088] Step 2: gradually add triethylamine to the dye-sensitized upconversion nanoparticles, test the upconversion luminescence intensity, select the optimal triethylamine dosage (1.52 mM), and obtain the upconversion system for testing ascorbic acid;

[0089] Step 3: gradually add different concentrations of ascorbic acid (0-150 μM) to the up-conversion system to test the up-conversion luminescence intensity;

[0090] Step 4: Draw a standard curve of the logarithmic value of ascorbic acid concentration and the upconversion luminescence intensity at 540 nm.

[0091] 0.1 μM organic dye and 22 mg / mL upconversion nanoparticles were added with 0, 5, 10, 15, 20, 25, 30, 40, 50, 75, 100 and 150 μM ascorbic acid in a heptanol solution containing 1.52 mM triethylamine, and the upconversion luminescence spectrum showed a gradually decreasing trend under 808 nm laser pumping with increasing concentration of ascorbic acid.

[0092] Example 4

[0093] The structural formula of the organic dye in this embodiment is as follows:

[0094]

[0095] In this embodiment, the rare earth doped up-conversion nanomaterial is β-NaYF4: 20% Yb 3+ ,20%Er 3+ @NaYF4:10%Nd 3+ / 10%Yb 3+ .

[0096] In this embodiment, the method for detecting ascorbic acid based on dye-sensitized upconversion luminescence specifically includes the following steps:

[0097] Step 1: Ultrasonicate the organic dye (4.0 μM) and the surface-modified rare earth upconversion nanoparticles (1 mg / mL) in a heptanol solution for 10 min to fully compound and disperse the upconversion nanoparticles and the organic dye;

[0098] Step 2: gradually add triethylamine to the dye-sensitized upconversion nanoparticles, test the upconversion luminescence intensity, select the optimal triethylamine dosage (50.0 mM), and obtain the upconversion system for testing ascorbic acid;

[0099] Step 3: gradually add different concentrations of ascorbic acid (0-600 μM) to the up-conversion system to test the up-conversion luminescence intensity;

[0100] Step 4: Draw a standard curve of the logarithmic value of ascorbic acid concentration and the upconversion luminescence intensity at 540 nm.

[0101] 2.5μM organic dye and 1.0mg / mL upconversion nanoparticles were added to a heptanol solution containing 50.0mM triethylamine at 0, 5, 10, 15, 20, 25, 30, 40, 50, 75, 100, 150, 250, 300, 400, 500 and 600μM ascorbic acid. With increasing the concentration of ascorbic acid, the upconversion luminescence spectrum showed a gradually decreasing trend under 785nm laser pumping.

[0102] Comparative Example 1

[0103] Taking the organic dye and upconversion nanoparticles in Example 1 as an example, the same technical solution is used, the only difference is that triethylamine is not added to the dye-sensitized upconversion system, and the addition of ascorbic acid of different concentrations to the upconversion system does not affect the luminescence of the dye-sensitized upconversion system. Figure 6 shown.

[0104] In summary, the method for detecting ascorbic acid provided by the present invention does not require chemical structure modification of the dye, and does not require further special treatment. It achieves high selectivity / high sensitivity and rapid detection of ascorbic acid through a simple, mild and low-cost method. The present invention provides a new method for designing highly selective and sensitive biological probes, and has broad application prospects in the field of biological molecule detection.

[0105] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting ascorbic acid based on dye-sensitized upconversion, characterized in that: include: An organic dye and rare earth doped upconversion nanoparticles are compounded in an organic solvent with a low dielectric constant to prepare a dye-sensitized upconversion nanoparticle dispersion of a specific concentration, wherein the organic dye is a near-infrared dye, and the near-infrared dye has a sulfonate group that can interact with the rare earth doped upconversion nanoparticles and is selected from at least one of IR808, IR820, IR845 and ICG, and the rare earth doped upconversion nanoparticles are selected from β-NaYF4:20%Yb 3+ ,20%Er 3+ and β-NaYF4:20%Yb 3 + ,20%Er 3+ @NaYF4:10%Nd 3+ / 10%Yb 3+ At least one of the organic solvents is heptanol, the concentration of the organic dye in the dye-sensitized upconversion nanoparticle dispersion is 0.1 to 4.0 μM, and the concentration of the rare earth-doped upconversion nanoparticles is 1 to 22 mg / mL; adding triethylamine to the dye-sensitized upconversion nanoparticle dispersion to obtain an upconversion system; The up-conversion system is mixed with a sample to be tested containing ascorbic acid, and the luminescence intensity of the up-conversion system is tested to achieve the detection of ascorbic acid.

2. The method according to claim 1, characterized in that include: A sample to be tested containing ascorbic acid is added to the up-conversion system, and triethylamine in the up-conversion system is used to enhance the nucleophilicity of ascorbic acid, resulting in luminescence quenching of the up-conversion system, thereby realizing the detection of ascorbic acid.

3. The method according to claim 1, characterized in that: The concentration of triethylamine in the up-conversion system is 0.5-53.28 mM.

4. The method according to claim 1, characterized in that: include: A series of standard sample solutions containing ascorbic acid at different concentrations are prepared, the series of standard sample solutions containing ascorbic acid at different concentrations are mixed with an up-conversion system, the up-conversion luminescence intensity of the series of standard sample solutions containing ascorbic acid at different concentrations is tested, a concentration-dependent standard curve of ascorbic acid is plotted with the logarithm of the concentration of ascorbic acid in the standard sample solution as the abscissa and the corresponding up-conversion luminescence intensity as the ordinate, and the detection limit of ascorbic acid is calculated; The up-conversion luminescence intensity of the sample solution containing ascorbic acid is detected and compared with the concentration-dependent standard curve of the ascorbic acid, so as to obtain the concentration of ascorbic acid in the sample solution to achieve the detection of ascorbic acid.

5. The method according to claim 4, characterized in that: The concentration of ascorbic acid in the standard sample solution containing ascorbic acid is 0-600 μM.

6. The method according to claim 4, characterized in that: The ordinate of the concentration-dependent standard curve is the corresponding up-conversion luminescence intensity excited at 785 nm or 808 nm.

7. The method according to claim 4, characterized in that: The ordinate of the concentration-dependent standard curve is the up-conversion luminescence intensity corresponding to 540 nm.

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