Phosphorescent material, method for preparing the same, and use thereof

Abstract

The application belongs to the technical field of phosphorescent materials, and particularly discloses a phosphorescent material, a preparation method thereof and application of the phosphorescent material in detection of ascorbic acid in serum. The phosphorescent material is prepared by mixing an aluminum sulfate aqueous solution and a uniform benzene tetraformic acid ethanol solution and performing a solvothermal reaction, has room temperature phosphorescent characteristics, water stability and high phosphorescent efficiency, has red shift of a phosphorescent emission wavelength and prolongation of a phosphorescent lifetime under a water-containing condition, can be used for detection of ascorbic acid in serum, has low detection limit, good selectivity, strong anti-interference capability and no need of pretreatment, and has wide application prospects in the fields of biological detection and clinical diagnosis.

Description

Technical Field

[0001] This invention belongs to the field of phosphorescent materials technology, and specifically relates to a phosphorescent material, its preparation method, and its application in detecting ascorbic acid in serum. Background Technology

[0002] Ascorbic acid (AA) is an essential water-soluble vitamin for the human body. As a powerful antioxidant, it protects cells from oxidative damage and serves as an indispensable cofactor in collagen synthesis, crucial for maintaining the health of connective tissues such as skin, blood vessels, and bones. Ascorbic acid also participates extensively in drug metabolism, immune regulation, and various enzymatic reactions. The level of ascorbic acid in the body directly reflects the severity of chronic wasting diseases. For example, cancer patients typically have much lower ascorbic acid (AA) concentrations than healthy individuals. This is not only because cancer accelerates AA metabolism and consumption but also because tumor-induced inflammatory responses further exacerbate its depletion. Therefore, accurate measurement of AA levels in cancer patients has significant clinical value for assessing disease progression and evaluating the effectiveness of nutritional interventions.

[0003] Currently, liquid chromatography-mass spectrometry (LC-MS) is the gold standard for ascorbic acid detection. This technique combines efficient chromatographic separation with specific mass spectrometric identification, exhibiting good sensitivity and selectivity. However, its practical application still faces inherent challenges. First, ascorbic acid is chemically unstable and easily oxidized, requiring strict avoidance of light and maintenance of a low-temperature environment during sample collection and pretreatment, significantly increasing the complexity of the analysis. Second, in complex biological matrices such as blood, coexisting components (e.g., proteins, pigments) may produce matrix effects, affecting the ionization efficiency of the target substance and thus reducing the accuracy of quantitative analysis. Third, LC-MS instruments are expensive and have high maintenance costs, limiting their widespread application in routine laboratories. Therefore, there is an urgent need to develop a simple, accurate, and reliable method for ascorbic acid detection suitable for complex biological samples to meet the clinical monitoring needs of related diseases.

[0004] Optical sensing technology is widely used in life sciences, medical diagnostics, and environmental monitoring due to its high selectivity, visual data readability, and ease of operation. Among various optical probes, fluorescent (FL) probes have been studied most extensively, with advantages including rapid response, support for multi-channel detection, and the ability to analyze a variety of targets. However, the sensitivity and signal-to-noise ratio (SNR) of traditional fluorescent probes are significantly reduced in biological samples, mainly due to the strong autofluorescence and scattered light generated by a large number of macromolecules and small molecules in matrices such as blood and urine. To eliminate such interference, complex pretreatment processes are required (e.g., heating, filtration, and precipitation). While these steps can remove large particles or macromolecules, they are ineffective for some small fluorescent molecules and may still affect detection results. In contrast, time-gated room-temperature phosphorescence (RTP) sensing technology employs a delayed detection mode after excitation, which effectively suppresses autofluorescence and scattering noise, thereby significantly improving the signal-to-noise ratio (SNR), sensitivity, and measurement stability. Despite these advantages, RTP sensing still faces two major challenges: (i) in aqueous media, phosphorescent probes are strongly quenched by water and oxygen through non-radiative triplet exciton inactivation; (ii) low triplet exciton utilization limits its sensitivity in trace analysis. Therefore, developing efficient, water-stable phosphorescent probes to achieve direct and accurate detection of ascorbic acid in biological matrices is crucial for advancing time-gated biosensing technology. Summary of the Invention

[0005] This invention develops a highly efficient phosphorescent material with excellent water stability through a coordination rigidity strategy. Unlike traditional RTP materials, which are susceptible to severe deactivation by water and oxygen, this highly efficient Al… 3+ -PMA coordination effectively immobilizes the ligand structure, suppresses non-radiative decay, and prolongs the phosphorescence lifetime of RTP under aqueous dispersion conditions. Benefiting from this excellent water stability and the oxygen scavenging properties of AA, the phosphorescent material exhibits a sensitive "on" response to AA, with a detection limit as low as 66 nM. More importantly, the phosphorescent material demonstrates excellent resistance to interference from complex biological matrices, enabling direct quantitative analysis of AA in human serum without pretreatment, with good recovery rates and high agreement with LC-MS gold standard results.

[0006] In view of this, the purpose of the present invention is to provide a phosphorescent material with excellent water stability and high efficiency, as well as its preparation method and application.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] The present invention also provides a method for preparing a phosphorescent material, comprising: mixing an aqueous solution of aluminum sulfate with an ethanolic solution of pyromellitic acid and carrying out a solvothermal reaction to obtain the phosphorescent material.

[0009] In some embodiments, the molar ratio of aluminum sulfate to pyromellitic acid is 4:1.

[0010] In some embodiments, the solvothermal reaction temperature is 200°C and the time is 300 min.

[0011] In some embodiments, the concentration of the aluminum sulfate aqueous solution is 1 mmol / ml, and the concentration of the pyromellitic acid ethanol solution is 0.25 mmol / ml.

[0012] This invention also provides a phosphorescent material prepared by the above method. The phosphorescent material exhibits room-temperature phosphorescence properties and water stability; under aqueous solution conditions, the phosphorescence emission wavelength exhibits a redshift compared to anhydrous conditions, and the phosphorescence lifetime is extended.

[0013] The present invention also provides the application of the above-mentioned phosphorescent material in the preparation of a kit or sensor for detecting ascorbic acid.

[0014] The present invention also provides a kit for detecting ascorbic acid, the kit comprising the above-mentioned phosphorescent material.

[0015] The present invention also provides a method for detecting ascorbic acid in a sample for non-diagnostic purposes, comprising: contacting the sample to be tested with the above-mentioned phosphorescent material, detecting the change in phosphorescence intensity, and determining the content of ascorbic acid in the sample based on the positive correlation between phosphorescence intensity and ascorbic acid concentration.

[0016] In some specific embodiments, the sample to be tested is serum, which does not require pretreatment, and the detection limit of ascorbic acid is 66 nM, with a linear range of 0.1-10 µM.

[0017] The beneficial effects of this invention are as follows: This invention mixes an aqueous solution of aluminum sulfate with an ethanolic solution of pyromellitic acid and performs a solvothermal reaction to obtain a phosphorescent material with excellent water stability and high efficiency. Unlike traditional RTP materials, which are easily deactivated by water and oxygen, the phosphorescent material of this invention utilizes a highly efficient Al... 3+ -PMA coordination effectively immobilizes the ligand structure, suppresses non-radiative decay, and prolongs the phosphorescence lifetime of RTP under aqueous dispersion conditions. Benefiting from this excellent water stability and the oxygen scavenging properties of AA, the phosphorescent material exhibits a sensitive "on" response to AA, with a detection limit as low as 66 nM. More importantly, the phosphorescent material demonstrates excellent resistance to interference from complex biological matrices, enabling direct quantitative analysis of AA in human serum without pretreatment, with good recovery rates and high agreement with the LC-MS gold standard results. This invention provides a feasible solution for the sensitive detection of AA in complex clinical samples, opening new avenues for disease progression monitoring, point-of-care testing, and precision medicine applications in cancer patients.

[0018] In addition, the preparation method described in this invention is simple, mild, uses inexpensive and readily available raw materials, has a high yield, and is environmentally friendly. It does not involve any toxic or harmful solvents or reagents and is easy to scale up for industrial production. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the synthesis route of Al / PMA-PMs in an embodiment of the present invention.

[0020] Figure 2 These are scanning electron microscope (SEM) images of Al / PMA-PMs from an embodiment of the present invention.

[0021] Figure 3 This is an example of the element distribution mapping diagram of Al / PMA-PMs in an embodiment of the present invention.

[0022] Figure 4 This is the full spectrum of Al / PMA-PMs X-ray photoelectron spectroscopy (XPS) in an embodiment of the present invention.

[0023] Figure 5 This is a high-resolution XPS spectrum of Al / PMA-PMs in an embodiment of the present invention; wherein, a: C1s, b: O1s, c: Al2p.

[0024] Figure 6 X-ray diffraction (XRD) spectra of Al / PMA-PMs, aluminum sulfate (Al2(SO4)3), and PMA powders.

[0025] Figure 7 This invention relates to the water stability and color-harmonic photoluminescence properties of Al / PMA-PMs in embodiments of the present invention; wherein, a: three-dimensional photoluminescence (PL) spectrum of Al / PMA-PMs powder; b: three-dimensional phosphorescence spectrum of Al / PMA-PMs powder; c: photomicrograph of Al / PMA-PMs powder under 302nm ultraviolet light irradiation in the water content range of 0% to 800%; d: maximum phosphorescence emission intensity of Al / PMA-PMs under different water contents; e: phosphorescence lifetime of Al / PMA-PMs under different water contents; f: photoluminescence quantum yield and phosphorescence quantum yield results of Al / PMA-PMs under different water contents.

[0026] Figure 8 The effects of different water contents and reaction times on the room temperature phosphorescence (RTP) luminescence of Al / PMA-PMs were investigated.

[0027] Figure 9 Three-dimensional phosphorescence spectra of Al / PMA-PMs with different water contents; where a: 100% water content, b: 200% water content, c: 400% water content, d: 600% water content, and e: 800% water content.

[0028] Figure 10 A cyclic 90℃ heating-water treatment system enables reversible switching of water-induced phosphorescence colors.

[0029] Figure 11 Photographs of the Tyndall effect in the Al / PMA-PMs@800% system.

[0030] Figure 12 The results of the optical modulation mechanism study are as follows: a: phosphorescence emission spectrum of PMA powder; b: phosphorescence emission spectrum of Al / PMA-PMs@800%@C@ND; c: phosphorescence emission spectrum of Al / PMA-PMs@800%@90℃; d: phosphorescence emission spectrum of Al / PMA-PMs@800%@200℃; e: phosphorescence lifetime curves of Al / PMA-PMs@800%@C@ND and Al / PMA-PMs@800%@90℃; f: FT-IR spectral results of Al / PMA-PMs@800%@C@ND and Al / PMA-PMs@800%@90℃; g: energy level diagram of PMA in aqueous solution; h: energy level diagram of Al / PMA-PMs@800% sample; i: energy level diagram of Al / PMA-PMs sample. Each diagram includes inset photographs taken under 302nm ultraviolet light irradiation and after removal.

[0031] Figure 13 The phosphorescence spectra of Al / PMA-PMs@800% after adding different concentrations of ascorbic acid (AA) are shown, with an excitation wavelength of 320 nm.

[0032] Figure 14 The phosphorescence spectrum of Al / PMA-PMs@800% after adding various interfering substances is shown, with an excitation wavelength of 320nm.

[0033] Figure 15The performance of Al / PMA-PMs@800% in ascorbic acid detection and clinical validation is shown below; where a: calibration curve of RTP phosphorescence intensity versus ascorbic acid concentration in aqueous solution; b: selectivity of Al / PMA-PMs@800% for ascorbic acid relative to various biological interfering agents (ascorbic acid: 50 μM; interfering agent: 500 μM; excitation wavelength: 320 nm); c: phosphorescence decay lifetime of Al / PMA-PMs@800% at different ascorbic acid concentrations; d: ascorbic acid based on oxygen scavenging principle. Schematic diagram of the acid-on-demand detection mechanism; e: Fluorescence spectrum of fetal bovine serum under 320nm excitation, showing a strong autofluorescence background; f: Comparison of Al / PMA-PMs and LC-MS methods for determining ascorbic acid concentration in clinical serum samples, where probe represents the Al / PMA-PMs test result and LC-MS represents the LC-MS test result; g: Linear relationship between the ascorbic acid concentration measured by Al / PMA-PMs and the LC-MS measured value, including the regression equation and R. 2 The values ​​are: probe represents the Al / PMA-PMs test result, LC-MS represents the liquid chromatography-mass spectrometry test result; h: the relative error between the Al / PMA-PMs measured value and the LC-MS reference value. Detailed Implementation

[0034] It should be understood that the embodiments described are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made to the embodiments by those skilled in the art based on the above description of the invention still fall within the scope of protection of the present invention.

[0035] It should be noted that all experimental materials in the embodiments of this invention, unless otherwise specified, are commercially available. Experimental methods in the embodiments of this invention, unless otherwise specified, are generally performed according to conventional experimental methods or methods recommended by the manufacturers of the experimental materials. It should also be noted that in this invention, RTP represents room temperature phosphorescence, and AA represents ascorbic acid.

[0036] 1. The experimental reagents involved in the embodiments of the present invention include the following:

[0037] PMA (98%) and AA (99%) were purchased from Energy Chemical Co., Ltd.; aluminum sulfate (99.99%), lysine (Lys, 98%), glutathione (GSH, 98%), cysteine ​​(Cys, 97%), and uric acid (UA, 98%) were all purchased from Adamas-betaReagent Co., Ltd.; N-acetylcysteine ​​(NAC, 97%), methionine (Met, 97%), and magnesium sulfate (AR) were supplied by Shanghai Lingfeng Chemical Reagent Co., Ltd.; sodium chloride (99.99%), sodium fluoride (99.99%), and sodium sulfate (99.99%) were purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; potassium sulfate (99.99%) and zinc sulfate (99.99%) were purchased from Sigma-Aldrich; and ethanol (95%) was supplied by Shanghai Boer Chemical Reagent Co., Ltd. All reagents were dissolved in 18.2 MΩ·cm ultrapure water.

[0038] 2. The experimental equipment involved in the embodiments of the present invention includes the following:

[0039] Photoluminescence (PL) spectra, phosphorescence spectra, and phosphorescence lifetimes were measured using an FLS1000 steady-state / transient fluorescence spectrometer; UV-Vis absorption spectra were recorded using a Lambda 950 UV-Vis-NIR spectrophotometer; scanning electron microscopy (SEM) images were acquired using a Helios G4 UC scanning electron microscope; powder X-ray diffraction (XRD) patterns were obtained using an 18KW / D / max2550VB / PC rotating anode X-ray powder diffractometer; Fourier transform infrared (FT-IR) spectra were acquired using a Nicolet 6700 FT-IR spectrometer; X-ray photoelectron spectroscopy (XPS) data were acquired using an Escalab 250Xi X-ray photoelectron spectrometer; and elemental distribution analysis was performed using energy-dispersive X-ray spectroscopy (EDS) combined with field emission scanning electron microscopy.

[0040] Example 1: Preparation of phosphorescent material Al / PMA-PMs

[0041] 0.5 mmol of pyromellitic acid (0.127 g) was dissolved in 2 ml of ethanol, and 2 mmol of aluminum sulfate (0.684 g) was dissolved in 2 ml of ultrapure water. The two solutions were then mixed and transferred to a 10 mL screw-top glass bottle, and heated at 200 °C for 300 minutes. The resulting powder product was designated Al / PMA-PMs, which is the phosphorescent material, with a yield of 61.47%. Figure 1 ).

[0042] Example 2 Characterization of phosphorescent materials Al / PMA-PMs

[0043] The Al / PMA-PMs obtained in Example 1 were characterized. SEM images showed that the Al / PMA-PMs had an irregular morphology. Figure 2 The elemental distribution diagram shows that Al / PMA-PMs are composed of aluminum, sulfur, oxygen, and carbon, and the uniform elemental distribution proves that their synthesis process is homogeneous. Figure 3 XPS spectral analysis quantitatively showed that the atomic composition was: oxygen (50.14 atomic%), carbon (37.82 atomic%), sulfur (6.72 atomic%), and aluminum (5.32 atomic%). Figure 4 High resolution C 1 The sXPS spectrum shows a characteristic peak at 289.2 eV, indicating the presence of abundant carboxyl / carboxylate groups. Figure 5 a); High-resolution O ¹ The sXPS spectrum shows peaks corresponding to Al-O bonds (534.8 eV) and water (533.4 eV). Figure 5 b); High-resolution Al²pXPS spectroscopy further confirmed the presence of Al-O bonds ( Figure 5 c), revealing Al 3+ Effective coordination between ions and PMA carboxylic acid groups.

[0044] Powder XRD pattern ( Figure 6 As can be seen, Al / PMA-PMs exhibit broad diffraction bands and multiple sharp diffraction peaks, which are significantly different from the diffraction characteristics of aluminum sulfate and PMA. These results clearly indicate that the formation of Al / PMA-PMs is attributed to Al. 3+ The ions coordinate with PMA through Al-O bonds.

[0045] Example 3: Optical performance testing of phosphorescent material Al / PMA-PMs

[0046] The optical properties of the Al / PMA-PMs prepared in Example 1 were investigated. Three-dimensional transient photoluminescence (PL) spectroscopy showed that the Al / PMA-PMs exhibited excitation-independent photoluminescence, with a maximum emission wavelength of 340 nm. Figure 7 a). Three-dimensional phosphorescence spectroscopy shows that Al / PMA-PMs exhibit strong, excitation-independent blue phosphorescence under excitation at 250 nm and 300 nm, with a maximum phosphorescence emission wavelength of 447 nm ( Figure 7 b).

[0047] To investigate the effect of water on the optical properties of Al / PMA-PMs, 40 mg of powdered Al / PMA-PMs were reacted with different volumes of water (40, 80, 160, 240, and 320 μL) for 9 hours to prepare solutions of different concentrations for optical property studies. Figure 7As shown in c, under 302nm ultraviolet light irradiation, the Al / PMA-PMs powder sample exhibits strong blue phosphorescence; after water treatment, the phosphorescence gradually transitions from blue to green, and the color change is completed within 3 hours. Figure 8 Normalized phosphorescence spectra show that as water content increases, the phosphorescence emission wavelength redshifts significantly from 447 nm to 535 nm. When the water content reaches 200%, the emission wavelength stabilizes at 535 nm. Figure 7 d、 Figure 9 Furthermore, the phosphorescence lifetime increased with increasing water content, significantly extending from the original value of 479.72 ms (Al / PMA-PMs powder) to 1073.55 ms (Al / PMA-PMs@800%). Figure 7 e). Conversely, both photoluminescence quantum yield and phosphorescence quantum yield decreased significantly, from 19.89% (Al / PMA-PMs powder) to 0.12% (Al / PMA-PMs@800%), and from 16.65% (Al / PMA-PMs powder) to 0.07% (Al / PMA-PMs@800%), respectively. Figure 7 f), this decay is mainly attributed to the transition from short-lived FL to long-lived RTP, where the increased lifetime reflects the slowing of the excited-state transition and decay process. At the same time, changes in water-induced phosphorescence also have an impact. These changes are highly reversible; the color of RTP changes after the addition of water and returns to its initial state after the removal of water. Figure 10 ).

[0048] Example 4: Optical modulation mechanism of phosphorescent material Al / PMA-PMs

[0049] The water stability and color regulation mechanism of RTP were studied using Al / PMA-PMs@800% as a typical case. Al / PMA-PMs powder can form a stable nano-suspension in water at a concentration of 800%. Figure 11 PMA exhibits a green RTP spectrum in its dry state, with a maximum phosphorescence emission peak at 535 nm. Figure 12 a), which is consistent with the characteristics of Al / PMA-PMs@800%. After centrifugation and natural drying, the resulting sample (Al / PMA-PMs@800%@C@ND) still maintains the maximum phosphorescence emission peak at 535 nm, accompanied by a shoulder peak at approximately 450 nm. Figure 12 b). However, in the sample dried at 90℃ (Al / PMA-PMs@800%@90℃), the phosphorescence emission peak at 535nm almost completely disappeared, while the phosphorescence emission peak at 450nm became the dominant peak. Figure 12c). The sample obtained by further increasing the temperature to 200℃ (Al / PMA-PMs@800%@200℃) showed phosphorescence emission only at 450nm. Figure 12 This is consistent with the initial emission characteristics of Al / PMA-PMs. The phosphorescence lifetime decreased from 1050.84 ms (Al / PMA-PMs@800%@C@ND) to 336.98 ms (Al / PMA-PMs@800%@90℃), confirming the phenomenon that the phosphorescence emission peak shifts with increasing temperature. Figure 12 e). These results indicate that as the temperature increases, the phosphorescence emission peak can shift from 535 nm to approximately 450 nm.

[0050] Reaction temperature is a key factor affecting the degree of polymerization of organometallic materials; higher temperatures generally lead to higher degrees of polymerization, a conclusion clearly supported by FT-IR spectroscopy results. Figure 12 f). Al / PMA-PMs in the range of 3800 to 2600 cm -1 A strong and broad absorption band is observed within the range, a feature attributed to the interaction of hydroxyl groups in PMA with water molecules via hydrogen bonds and the hydration of Al. 3+ The hydroxyl groups in the complex. Compared to Al / PMA-PMs, Al / PMA-PMs@800%@C@ND exhibits multiple sharp absorption peaks, indicating a lower degree of polymerization; therefore, its vibrational modes are more pronounced than those of PMA. After treatment at 90℃ (Al / PMA-PMs@800%@90℃), the absorption bands broaden and their number decreases, strongly indicating that high-temperature treatment promotes the polymerization reaction, significantly suppresses the vibrational motion of PMA, and reduces the number of infrared vibrational absorption peaks.

[0051] like Figure 12 As shown in g, due to the strong nonradiative quenching effect of water and oxygen on triplet excitons, obvious RTP luminescence cannot be observed with the naked eye in PMA aqueous solution; however, when PMA forms a nano-suspension in aqueous solution (Al / PMA-PMs@800%), it emits a strong green RTP emission originating from PMA itself. Figure 12 h). This result indicates that PMA and Al 3+ The coordination between ions can effectively suppress the movement of PMA molecules, thereby suppressing non-radiative quenching and achieving bright RTP luminescence. Subsequently, Al / PMA-PMs composite materials can be prepared through high-temperature polymerization. Figure 12i): High polymerization significantly enhances the rigidity of the PMA structure. Amorphous luminescent components typically exhibit redshifted emission characteristics due to their energy-accessible conical intersection points. The lowest energy point of the excited state with a small band gap causes a redshift in RTP emission. Conversely, conformational rigidification achieved through polymerization blocks such energy pathways, resulting in a blueshift in RTP emission. Therefore, the increased rigidity from polymerization alters the position of the absorption peak. The emission wavelength extends from 535 nm to approximately 450 nm, exhibiting a significant blueshift.

[0052] Example 5: Detection of AA in aqueous solution

[0053] 20 µL of AA solutions with different concentrations (0, 0.5, 1, 3, 5, 7.5, 10, 30, 50, 75, 100, 200 µM) were added to 180 µL of Al / PMA-PMs@800% solution and mixed thoroughly to achieve final AA concentrations of 0, 0.05, 0.1, 0.3, 0.5, 0.75, 1.0, 3.0, 5.0, 7.5, 10, and 20 µM. The spectra were then recorded at an excitation wavelength of 320 nm. The results showed that the phosphorescence emission intensity continuously increased with increasing AA concentration. Within the concentration range of 0.1–10 µM, the RTP intensity was positively correlated with the AA concentration, and the detection limit was 66 nm. Figure 13 , Figure 15 a).

[0054] To evaluate the selectivity of AA detection, other common interfering substances (GSH, Cys, UA, NAC, Met, Lys, Cl) at a concentration of 0.5 mM in Al / PMA-PMs@800% solution were tested using the same method. - ,

[0055] F - SO4 2- K + Zn 2+ and Mg 2+ The results showed that GSH, Cys, UA, NAC, Met, Lys, and Cl were included. - F - SO4 2- K + Zn 2+ and Mg 2+ Common biological interfering agents, including those mentioned above, have almost no effect on RTP signals. Figure 14 , Figure 15 (b) This demonstrates that Al / PMA-PMs@800% exhibits high selectivity for AA.

[0056] The phosphorescence lifetime results of Al / PMA-PMs@800% at different ascorbic acid concentrations showed that the phosphorescence lifetime of AA at a concentration of 10µM was higher than that of AA at a concentration of 5µM. Figure 15 c) Since dissolved oxygen typically shortens phosphorescence lifetime, the removal of oxygen by AA correspondingly extends the lifetime of Al / PMA-PMs@800%. These results confirm that the sensitive "on-off" detection effect originates from the oxygen removal effect of AA, thereby simultaneously enhancing the RTP intensity and lifetime of oxygen-quenched Al / PMA-PMs@800%. Figure 15 d).

[0057] Example 6: Detection of AA in fetal bovine serum

[0058] Biological samples contain various macromolecules and small molecules, which often produce strong autofluorescence and scattered light under short-wavelength excitation conditions. This significantly increases the difficulty of detection, and traditional fluorescent probes typically require complex sample pretreatment steps. To evaluate the reliability of Al / PMA-PMs in detecting AA in complex matrices, AA solutions (concentrations of 50 and 100 μM) were prepared using fetal bovine serum. Subsequently, 20 μL of each spiked serum solution was added to 180 μL of Al / PMA-PMs@800% solution and mixed thoroughly to obtain Al / PMA-PMs@800% solutions with AA concentrations of 5 μM and 10 μM, respectively. Finally, AA concentration was detected at an excitation wavelength of 320 nm. Fetal bovine serum exhibited strong autofluorescence in the range of 350 nm to 700 nm at an excitation wavelength of 320 nm. Figure 15 e). When using the standard additive method to detect AA in this matrix, no pretreatment is required, and the recovery rate can reach an excellent level of 100.8% to 101.4% (Table 1).

[0059] Table 1. Results of ascorbic acid detection in fetal bovine serum samples.

[0060] 5.0 5.07 101.4 4.4 10.0 10.08 100.8 5.6

[0061] Note: a is the average of three parallel tests; b is the recovery rate (%) = measured concentration / spiked concentration × 100%.

[0062] These results indicate that Al / PMA-PMs can serve as ideal phosphorescent probes for the direct and sensitive detection of AA in complex biological matrices.

[0063] Example 7: Detection of AA in human serum samples

[0064] To further evaluate the practical applicability of Al / PMA-PMs in the quantitative analysis of ascorbic acid (AA), seven serum samples from healthy individuals and cancer patients were analyzed, with liquid chromatography-mass spectrometry (LC-MS) used as the gold standard reference. The ascorbic acid concentrations determined by Al / PMA-PMs were highly consistent with the LC-MS results. Figure 15 f). Linear regression analysis yielded the correlation equation y = 0.98x + 0.36, with a coefficient of determination R² = 0.995, indicating good linear consistency between the two equations and negligible systematic bias. Figure 15 g). Furthermore, the relative errors between the Al / PMA-PMs probes and LC-MS results remained within ±10% in all test samples, confirming that Al / PMA-PMs, as probes, have good detection accuracy in complex biological matrices. Figure 15 As shown in Table 2, the recoveries ranged from 94.04% to 109.55%, and the relative standard deviations (RSDs) of the three parallel determinations were all less than 8.5%.

[0065] Table 2. Recovery rate and precision of serum AA determination in healthy individuals (Nos. 1 and 2) and cancer patients (Nos. 3–7)

[0066]

[0067] Note: a is the average of three parallel tests; b is the reference concentration determined by liquid chromatography-mass spectrometry (LC-MS); c is the recovery rate (%) = measured concentration / reference concentration × 100%.

[0068] The results clearly showed that the ascorbic acid content in the serum of healthy individuals was significantly higher than that in the serum of cancer patients. In conclusion, this study demonstrates that the proposed probe possesses good accuracy, precision, and anti-interference capabilities, and can serve as a reliable tool for the quantitative analysis of ascorbic acid in human serum samples.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any modifications, equivalent substitutions, improvements, etc., within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a phosphorescent material, characterized in that, The process includes the following: mixing an aqueous solution of aluminum sulfate with an ethanolic solution of pyromellitic acid and carrying out a solvothermal reaction to obtain the phosphorescent material.

2. The method according to claim 1, characterized in that, The molar ratio of aluminum sulfate to pyromellitic acid is 4:

1.

3. The method according to claim 1, characterized in that, The solvothermal reaction temperature was 200℃ and the time was 300 min.

4. The method according to claim 1, characterized in that, The concentration of the aluminum sulfate aqueous solution is 1 mmol / ml, and the concentration of the pyromellitic acid ethanol solution is 0.25 mmol / ml.

5. The phosphorescent material prepared by the method according to any one of claims 1-4.

6. The use of the phosphorescent material of claim 5 in the preparation of a kit or sensor for detecting ascorbic acid.

7. A kit for detecting ascorbic acid, characterized in that, The kit contains the phosphorescent material as described in claim 5.

8. A method for detecting ascorbic acid in a sample for non-diagnostic purposes, characterized in that, include: The sample to be tested is brought into contact with the phosphorescent material described in claim 5, and the change in phosphorescence intensity is detected. The content of ascorbic acid in the sample is determined based on the positive correlation between phosphorescence intensity and ascorbic acid concentration.

9. The method according to claim 8, characterized in that, The sample to be tested was serum, and the detection limit of ascorbic acid was 66 nM, with a linear range of 0.1-10 µM.

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