Curcumin ratiometric fluorescent sensor fluorescent probe, curcumin and curcumin derivative detection method and device

Abstract

The invention provides a curcumin ratiometric fluorescent sensor fluorescent probe and a curcumin and derivative detection method and device, the curcumin ratiometric fluorescent sensor fluorescent probe material is a zinc metal organic complex [Zn2 (btec) (H2O) 2] n, and btec is a 1, 2, 4, 5-benzene tetracarboxylic acid radical ligand. The curcumin ratio type fluorescent sensor fluorescent probe is applied to curcumin detection, has ultrahigh sensitivity and selectivity, has the detection limit reaching nanomole level (10 <-9 > M magnitude), has response time as short as tens of seconds, has strong anti-interference capability and can be recycled for multiple times.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary field of analytical chemistry and materials science, specifically relating to a fluorescent probe for a curcumin ratiometric fluorescent sensor based on a metal-organic framework (MOF), and a method and apparatus for detecting curcumin and its derivatives. Background Technology

[0002] Curcumin (CUR) is a naturally occurring polyphenolic bioactive substance found in the rhizome of turmeric, possessing significant pharmacological effects. Current research indicates that curcumin exhibits unique biological activities in anti-inflammation, anti-oxidation, anti-tumor, antibacterial, and neuroprotective properties, making it one of the important candidate molecules in the field of natural medicine research. For example, curcumin can reduce the production of inflammatory mediators at the source by inhibiting key signaling pathways such as nuclear factor κB (NF-κB), thereby exerting anti-inflammatory and disease-relieving effects. Besides its medicinal value, curcumin is widely used in the food industry as a natural pigment and food additive, and in the cosmetics industry as a core active ingredient with antioxidant functions. Its safety and natural origin make it a highly sought-after functional raw material in the market.

[0003] However, the use of curcumin is not entirely risk-free. Numerous studies have indicated that excessive intake of curcumin may cause adverse reactions such as gastrointestinal discomfort, nausea, and abnormal liver function. Therefore, international food safety organizations have set strict limits on the amount of curcumin used. The European Union stipulates a maximum daily intake of 3 mg / kg body weight; China's national standard (GB 2760-2014) also sets maximum limits for curcumin addition in different food categories, such as 200 mg / kg for candy and 100 mg / kg for soy sauce. It is worth noting that due to huge market demand, some unscrupulous companies adulterate their products with inferior pigments or use substandard processes, resulting in counterfeit curcumin products. This poses a serious threat to consumer health and the standardized development of the industry. Therefore, developing a rapid, accurate, and on-site testing method for curcumin analysis is of significant practical importance.

[0004] Currently, the main methods for detecting curcumin include thin-layer chromatography, ultraviolet-visible spectrophotometry, high-performance liquid chromatography (HPLC), capillary electrophoresis, and electrochemical detection. Although these methods have high sensitivity and reliability, they also have significant shortcomings: expensive instruments and equipment, complex sample pretreatment, long detection process, and high technical requirements for operators. Especially in the actual needs of food production line supervision, market circulation supervision, or on-site rapid screening, these methods are difficult to achieve real-time, portable, and efficient detection.

[0005] Metal-organic frameworks (MOFs), as a novel type of porous crystalline material, are showing great potential in the field of fluorescence sensing due to their highly tunable structure, excellent optical properties, and rich functionalization possibilities. However, no literature reports the use of luminescent MOFs to construct fluorescence sensing systems for curcumin, an important food active ingredient. This indicates that current technologies have not yet covered the gaps in curcumin detection regarding requirements for portability, low cost, high selectivity, high sensitivity, and visual interpretability. Summary of the Invention

[0006] In view of this, the purpose of this invention is to overcome the shortcomings of the prior art in curcumin detection, and to provide a curcumin ratiometric fluorescent sensor fluorescent probe and a method and apparatus for detecting curcumin and its derivatives.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a fluorescent probe for a curcumin ratiometric fluorescent sensor, characterized in that the fluorescent probe material is a zinc metal-organic complex [Zn2(btec)(H2O)2]. n Wherein, btec is a 1,2,4,5-benzenetetracarboxylate ligand, and n in the complex usually refers to the coordination number, that is, the coordination number of the central ion is 2, 4, 6, or 8.

[0008] The present invention provides a curcumin-based ratiometric fluorescent sensor probe as described above. Further, the zinc metal-organic complex [Zn2(btec)(H2O)2] is described. n The crystal structure is a three-dimensional coordination polymer with binuclear Zn. 2+ The material is composed of a three-dimensional porous network of clusters and rigid polycarboxylic acid ligands; it emits bright blue fluorescence (emission peak at approximately 426 nm) under ultraviolet excitation and exhibits good thermal stability.

[0009] The curcumin ratiometric fluorescent sensor probe of the present invention further comprises the zinc metal-organic complex [Zn2(btec)(H2O)2]. n The following method was used to obtain the crystal product: Zn(NO3)2 and H4btec were dissolved in a mixed solvent of water and acetonitrile, and the mixture was stirred at room temperature, heated, and then crystallized by programmed cooling.

[0010] The curcumin ratiometric fluorescent sensor probe of the present invention further comprises a Zn(NO3)2 to H4btec molar ratio of 2:1, a reaction temperature of 100-120℃, and a reaction time of 60-80 hours. Preferably, the reaction is carried out in an oven at 110℃ for 72 hours, followed by a programmed cooling to room temperature at a rate of 5℃ per hour for crystallization.

[0011] The present invention also provides a method for detecting curcumin and its derivatives, comprising the curcumin ratiometric fluorescent sensor and fluorescent probe described in any one of the above-mentioned methods.

[0012] The present invention further describes a method for detecting curcumin and its derivatives as described above. Specifically, the curcumin ratiometric fluorescent sensor fluorescent probe material is dispersed in the liquid sample to be tested and excited by a near-ultraviolet light source. The change in the ratio of fluorescence quenching of the fluorescent probe material to fluorescence enhancement of curcumin enables curcumin detection.

[0013] The present invention further refines the method for detecting curcumin and its derivatives as described above by establishing a fluorescence ratio signal based on the intrinsic emission of the fluorescent probe material at 426 nm and the emission of the analyte curcumin at approximately 538 nm. When detecting curcumin, the emission wavelengths are set to 426 nm and 538 nm, and the fluorescence intensity ratio I is used to determine the fluorescence ratio. 538 / I 426 Quantitative analysis was performed based on a linear relationship with curcumin concentration, such as... Figure 3 As shown in (c), the linear equation is I. 538 / I 426 = 1.50×10 6 [CUR] +0.1352, passing the detection limit formula 3σ / K (K=1.50 × 10⁻⁶). 6 Calculation (σ represents the standard deviation of the target substance in the sample) shows that the detection limit of CUR is 4.68 × 10⁻⁶. -9 M, linear range is 10 -9 M to 2×10 -7 M.

[0014] The present invention provides a method for detecting curcumin and its derivatives as described above, wherein the excitation wavelength of the near-ultraviolet light source is 328 nm.

[0015] During detection, the fluorescent probe of the curcumin ratiometric fluorescence sensor is mixed with the sample in suspension and excited using a near-UV light source (approximately 328 nm). Without curcumin, the probe emits strong blue fluorescence at 426 nm. When curcumin is present in the sample, the 426 nm emission of the probe is quenched, while curcumin produces strong green fluorescence at 538 nm. As the curcumin concentration increases, the fluorescence intensity at 426 nm gradually decreases while that at 538 nm gradually increases, thus forming Ig. 538 / I 426 The ratio signal; where at 10 -9 ~2×10 -7 In the low concentration range of M, the fluorescence intensity ratio I 538 / I 426 It showed a good linear relationship with curcumin concentration (correlation coefficient R² = 0.992); the detection limit calculated using the 3σ / K method was as low as 4.68 × 10⁻⁶.-9 M.

[0016] Experiments show that the fluorescence detection of this invention completes the response in approximately 30 seconds, exhibiting excellent speed and selectivity: in systems containing various food additives and interfering substances, only curcumin significantly enhances the probe's 538nm emission with a ratio signal exceeding 20 times, while other substances have almost no effect on the probe fluorescence. The probe can be reused multiple times after washing and centrifugation; after 5 cycles of detection, the fluorescence intensity and I... 538 / I 426 The ratio showed no significant decrease, and PXRD (X-ray diffraction) results indicated that the crystal structure remained stable before and after cycling.

[0017] The present invention also provides a detection device for curcumin and its derivatives, comprising a detection device body, an excitation wavelength adjustable light source, and an intelligent spectral or image acquisition system. The detection device body is provided with a cuvette slot, the light source corresponds to the cuvette slot, and the intelligent spectral or image acquisition system outputs the curcumin concentration by analyzing the fluorescence color change (B / G ratio).

[0018] The present invention provides a detection device for curcumin and its derivatives as described above. The main body of the detection device is made by 3D printing technology using ABS polymer, namely ABS resin (acrylonitrile-butadiene-styrene copolymer), and has the mounting positions for the light source and cuvette.

[0019] This invention utilizes zinc-organic metal complexes to create a three-dimensional metal-organic framework material [Zn2(btec)(H2O)2] with strong fluorescence emission properties. n This material not only exhibits stable and strong luminescence under UV excitation, but also boasts high structural stability, mild preparation conditions, low cost, and excellent cycling stability and anti-interference capabilities. More importantly, this invention is the first to discover that this material utilizes fluorescence resonance energy transfer and photoinduced electron transfer mechanisms to exhibit a highly selective fluorescence response to curcumin, achieving nanomolar levels (4.68 × 10⁻⁶) through ratiometric fluorescence changes. -9 It features ultra-high sensitivity detection (M) and has significant advantages such as fast response speed (about 30 seconds), strong anti-interference ability, and reusability.

[0020] This invention utilizes a portable cuvette device made with 3D printing technology and an automatic identification real-time quantitative analysis system to construct a portable intelligent detection platform that can be operated on-site without professional personnel, and can automatically output concentration by observing color changes with the naked eye. This platform not only simplifies the detection process and improves detection efficiency, but also provides a new technical path for on-site detection in food safety supervision and related industries. The system includes three stages: calibration, RGB signal processing, and data output. Specifically, it includes a calibration module to minimize errors caused by external influences, used for calibration and linear equation calculation within the linear concentration range using two known concentrations; an RGB signal processing module, used to identify and analyze RGB values ​​after the user uploads photographs of films with two known analyte concentrations, digitizing the image; a data output module, used by the user to select the linear equation to calculate (R, G, B, R / B, B / R, R / G, G / R, B / G, G / B) and output type (color ratio or log color ratio), inputting the corresponding concentration in the specified standard section, and identifying the calculable linear equation; and an identification and analysis module, used to identify and calculate the concentration of the analyte after inputting a photograph of a film with an unknown concentration.

[0021] This invention is the first to utilize the luminescent coordination polymer [Zn2(btec)(H2O)2]. n This invention provides a simple and rapid new ratiometric fluorescence sensing strategy for curcumin detection. Compared with existing technologies, the curcumin ratiometric fluorescence sensor probe of this invention exhibits ultra-high sensitivity and selectivity for curcumin, with a detection limit in the nanomolar range (10⁻⁶). -9 This real-time quantitative analysis system, operating on the order of megaliterans (M), boasts a response time as short as tens of seconds, strong anti-interference capabilities, and is reusable multiple times. Utilizing a smartphone, it enables on-site sampling and testing, significantly simplifying the detection process and reducing costs. Requiring no cumbersome sample pretreatment or large instruments, the system accurately determines curcumin content in complex matrices, demonstrating broad application prospects in food safety and pharmaceutical quality monitoring. Furthermore, due to the similarities between curcumin derivatives and curcumin in molecular skeletons, conjugated systems, and spectral responses, the detection method described in this invention can also be used for the identification and quantitative detection of curcumin derivatives. By establishing corresponding ratio signals and concentration calibration curves, extended detection applications for different curcumin derivatives can be achieved.

[0022] The zinc-based metal-organic framework material [Zn2(btec)(H2O)2] used in this invention n Its luminescence mainly originates from ligand-related emission and its modulation effect in the metal coordination environment. Therefore, the fluorescent probe of this invention replaces Zn with other transition metal ions. 2+Isomorphic materials that maintain similar coordination topology also fall under the category of equivalent substitutions in this invention, that is, other transition metal ions can replace Zn without changing the main light-emitting channel of the probe material. 2+ The resulting transition metal-polycarboxylic acid ligand coordination polymers, which are structurally isomorphic or similar, are also expected to achieve a ratioistic response to curcumin-induced fluorescence quenching / enhancement, thereby enabling highly sensitive detection of curcumin, and are also included within the scope of this invention. Attached Figure Description

[0023] Figure 1 The crystal structure of the fluorescent probe of the curcumin ratiometric fluorescent sensor of the present invention is shown in the following figures: (a) coordination environment of Zn ions in the complex; (b) polyhedral diagram of the binuclear unit; (c) one-dimensional binuclear chain structure along the c-axis; and (d) three-dimensional frame view along the c-axis. Figure 2 Characterization data for the fluorescent probe material of the curcumin ratiometric fluorescent sensor of this invention: (a) PXRD (X-ray diffraction), (b) thermogravimetric analysis and (c) infrared spectroscopy; Figure 3 The following graphs show the fluorescence response and linear relationship of the fluorescent probe material of the curcumin ratiometric fluorescent sensor of this invention applied to curcumin detection: (a) emission spectrum of the complex at different curcumin concentrations, (b) CIE plots of the complex at different curcumin concentrations, and (c) CUR at 10... -9 Up to 2×10 -7 Within the M concentration range, the I of the complex 538 / I 426 Linear relationship with CUR; Figure 4 The fluorescence response, time response, and anti-interference diagrams of the fluorescent probe material of the curcumin ratiometric fluorescent sensor of this invention applied to curcumin detection are shown in Figures (a), luminescence intensity of the complex with different food additives added, and (b), I. 538 / I 426 (c) Response time of the complex after adding LMFX solution, fluorescence spectra of complex + CUR and CUR (λex = 328 nm), (d) Anti-interference test of complex in the presence of other food additives for detecting CUR; Figure 5 To demonstrate the cyclic stability of the fluorescent probe of the curcumin ratiometric fluorescent sensor of the present invention, (a) is a schematic diagram of the effect of the number of cycles on the complex during the detection of CUR, and (b) are the X-ray powder diffraction patterns of the complex measured after one, three, and five cycles. Figure 6This is a schematic diagram of the FRET / PET mechanism in the fluorescence probe mechanism analysis of the curcumin ratiometric fluorescent sensor of the present invention. (a) UV spectra of the complex and various food additives, (b) excitation and emission spectra of CUR. Detailed Implementation

[0024] Example 1 The fluorescent probe for a curcumin-ratio fluorescent sensor can be prepared via a solvothermal method. Specifically, 0.060 g of zinc nitrate (Zn(NO3)2) and 0.024 g of tetracarboxylic acid ligand (H4btec) are dissolved in a mixed solvent of 5 mL deionized water and 5 mL acetonitrile. The solution is placed in a 25 mL polytetrafluoroethylene-lined reactor and magnetically stirred at room temperature for 30 minutes. The mixture is then heated in a 110°C oven for 72 hours, followed by cooling to room temperature at a rate of 5°C per hour. The resulting crystalline product is filtered, washed three times with water, and dried to obtain blue luminescent complex crystals, such as... Figure 2 (c) shows the infrared spectrum at 1612 cm⁻¹ -1 and 1380cm -1 The presence of a characteristic vibrational peak of the carboxylate group at this point indicates that the ligand has been deprotonated and reacted with Zn. 2+ Coordination, such as Figure 2 (a) The crystal structure of the MOF obtained from the crystallographic data sheet of the coordination compound was characterized by single-crystal XRD and belongs to the monoclinic crystal system space group. P 21 / c, the specific crystallographic parameters are shown in Table 1, proving that the target coordination compound was successfully obtained, such as... Figure 1 The crystal structures shown in (a)-(d) include the coordination environment of zinc ions and the three-dimensional framework.

[0025] Table 1. Crystallographic parameters of the fluorescent probe for the curcumin ratiometric fluorescent sensor

[0026] Example 2 Fluorescence ratio detection of curcumin content in solution: 2.0 mg of the curcumin ratio fluorescent sensor probe material crystal from Example 1 was weighed, finely ground, and dispersed in 2.7 mL of deionized water. A stable suspension was prepared by sonication for 30 minutes. 2.7 mL of the probe suspension was added to a cuvette of a fluorescence spectrophotometer, and its fluorescence emission spectrum was measured using an excitation wavelength of 328 nm. A strong background emission peak (curcumin ratio fluorescent sensor probe material) was observed at 426 nm. Then, a certain concentration of curcumin (CUR) standard solution was added dropwise to the cuvette, and the fluorescence spectrum was continuously monitored. As the CUR concentration gradually increased, the emission intensity of the curcumin ratio fluorescent sensor probe material at 426 nm significantly decreased, while a new emission peak appeared at approximately 538 nm, and its intensity gradually increased. The fluorescence color of the solution gradually changed from the initial blue to a bluish-green.

[0027] like Figure 3 Images (a)-(c) show the fluorescence spectral changes of the curcumin ratiometric fluorescent sensor probe material of the present invention at different CUR concentrations. It can be seen that I 538 The effect increases continuously with increasing CUR concentration, while I 426 The corresponding decrease; analysis shows that at a CUR concentration of 10... -9 ~2×10 -7 Within the range of M, I 538 / I 426 It showed a linear relationship with CUR concentration, with a correlation coefficient R² = 0.992; the limit of detection calculated according to the 3σ principle was 4.68 × 10⁻⁶. -9 M exhibits extremely high sensitivity.

[0028] Further anti-interference experiments were conducted, such as... Figure 4 As shown in (a)-(d), curcumin (the target analyte) and typical food preservatives such as sodium dehydroacetate, sodium diacetate, sodium benzoate, potassium sorbate, sodium lactate, calcium propionate, and propylparaben were added to the suspension of the curcumin ratiometric fluorescent sensor probe material of the present invention, respectively. The concentration of each substance was 1×10⁻⁶. -3 The results showed that only curcumin caused a significant increase in fluorescence at 538 nm and quenching of fluorescence at 426 nm in the complex, while other interfering substances caused only weak or almost imperceptible fluorescence changes, indicating that the probe of this invention has high specificity for curcumin. Furthermore, the probe suspension containing curcumin completed the fluorescence color transition from blue to green and achieved signal stability after standing for about 30 seconds, demonstrating a rapid response.

[0029] To verify the reusability of the probes, a cyclic test was performed on the same batch of curcumin ratiometric fluorescent sensor fluorescent probe complex suspensions, sequentially involving curcumin detection and washing / regeneration. For example... Figure 5 As shown in (a), the fluorescence intensity ratio (538 nm / 426 nm) of the zinc complex in its initial state was only 0.045, while after the addition of curcumin, this ratio could rise to 17, showing a significant color change. After 5 repeated cycles of use, the fluorescence intensity and I of the curcumin ratiometric fluorescent sensor fluorescent probe material of the present invention were significantly improved. 538 / I 426 The ratio showed almost no decay, and the performance remained stable, indicating that this zinc complex possesses good cyclic detection performance. Figure 5 As shown in (b), the PXRD (X-ray diffraction) pattern is consistent with that of the fresh sample, indicating that the probe material is structurally stable during cyclic detection and can be recycled multiple times. Figure 6As shown in (a), by comparing the emission spectrum of the complex with the UV spectra of various food additives, the UV absorption spectrum of CUR is at 430 nm, and the excitation of CUR is at 431 nm, while the emission of the complex is at 426 nm. Figure 6 As shown in (b), the CUR absorption spectrum and excitation spectrum have a large overlap with the emission spectrum of the complex; this overlap indicates that there is a Förster resonance energy transfer (FRET) process between the emission of the complex and the absorption of CUR.

[0030] This invention can employ a detection device for curcumin and its derivatives. The detection device may include a detection device body, an tunable excitation wavelength light source, and an intelligent spectral or image acquisition system. The detection device body is equipped with a cuvette slot, a light source mounting position, and an intelligent spectral or image acquisition system mounting position. The light source corresponds to the cuvette slot. The intelligent spectral or image acquisition system outputs the curcumin concentration by analyzing fluorescence color changes (B / G ratio). Specifically, a portable fluorescence detection device can be fabricated using 3D printing technology. The material is ABS engineering plastic, the light source is a high-intensity UV LED (365nm), a sample cell slot, and a position for fixing a smartphone. The structural design of this device allows adjustment of the distance between the light source and the sample, and between the sample and the camera, to obtain optimal excitation and imaging effects.

[0031] This invention also provides an automatic identification real-time quantitative analysis system, comprising three stages: calibration, RGB signal processing, and data output. Specifically, it includes a calibration module to minimize errors caused by external influences, used for calibration and linear equation calculation within a linear concentration range using two known concentrations; an RGB signal processing module, used to identify and analyze RGB values ​​after the user uploads photographs of films with two known analyte concentrations, digitizing the image; a data output module, used by the user to select the linear equation to calculate (R, G, B, R / B, B / R, R / G, G / R, B / G, G / B) and output type (color ratio or log color ratio), inputting the corresponding concentration in the specified standard section, and identifying the calculateable linear equation; and an identification and analysis module, used to identify and calculate the concentration of the analyte after inputting a photograph of a film with an unknown concentration. This system ensures that color can be digitized and enables portable sensor devices to perform quantitative analysis on-site.

[0032] 200 mg of curcumin-based ratiometric fluorescent probe material crystals were added to 270 mL of deionized water and sonicated for 30 minutes to prepare a batch probe suspension. 2.7 mL of this suspension was placed in a cuvette, and 300 µL of CUR standard solutions of different concentrations (concentration range 5 × 10⁻⁶) were added. -5 ~5×10 -3M). The cuvette was inserted into the slot of the 3D printing device, the sample was irradiated with a UV light source, and a photo of the front of the cuvette was taken using a smartphone camera. It was observed that as the CUR concentration increased, the fluorescence color of the excited solution in the cuvette gradually changed from blue to green. The automatic identification real-time quantitative analysis system, installed on the mobile phone application, analyzed the captured fluorescence image, extracted the intensity values ​​of the blue (B) and green (G) channels, and calculated the B / G ratio. The experiment yielded results at a CUR concentration of 5 × 10⁻⁶. -5 ~5×10 -3 Within the M range, there is a linear relationship between B / G and CUR concentration. Using a pre-established calibration curve, the real-time quantitative analysis system can automatically calculate the CUR concentration in the sample and display the results. Compared with traditional large-scale instrument analysis methods, this system is low-cost and easy to operate, and can be used for rapid on-site screening of curcumin content in food or environmental samples, thus having significant practical value.

Claims

1. A fluorescent probe for a curcumin ratiometric fluorescent sensor, characterized in that, The fluorescent probe material is a zinc-organic metal complex [Zn2(btec)(H2O)2]. n Wherein, btec is a 1,2,4,5-benzenetetracarboxylate ligand.

2. The curcumin ratiometric fluorescent sensor fluorescent probe according to claim 1, characterized in that, The zinc-organic metal complex [Zn2(btec)(H2O)2] n The crystal structure is a three-dimensional coordination polymer with binuclear Zn. 2+ A three-dimensional porous network composed of clusters and rigid polycarboxylic acid ligands.

3. The curcumin ratiometric fluorescent sensor fluorescent probe according to claim 2, characterized in that, The zinc-organic metal complex [Zn2(btec)(H2O)2] n The following method was used to obtain the crystal product: Zn(NO3)2 and H4btec were dissolved in a mixed solvent of water and acetonitrile, and the mixture was stirred at room temperature, heated, and then crystallized by programmed cooling.

4. The curcumin ratiometric fluorescent sensor fluorescent probe according to claim 3, characterized in that, The molar ratio of Zn(NO3)2 to H4btec is 2:1, the reaction temperature is 100-120℃, and the reaction time is 60-80 hours.

5. A method for detecting curcumin and its derivatives, characterized in that, Includes the curcumin ratio-type fluorescent sensor fluorescent probe as described in any one of claims 1 to 4.

6. The method for detecting curcumin and its derivatives according to claim 5, characterized in that, The fluorescent probe material of the curcumin ratiometric fluorescent sensor is dispersed in the liquid sample to be tested and excited by a near-ultraviolet light source. The change in the ratio of fluorescence quenching of the fluorescent probe material to fluorescence enhancement of curcumin enables the detection of curcumin.

7. The method for detecting curcumin and its derivatives according to claim 6, characterized in that, Based on the intrinsic emission of the fluorescent probe material at 426 nm and the emission of the analyte curcumin at approximately 538 nm, a fluorescence ratio signal is formed. When detecting curcumin, the emission wavelengths are set to 426 nm and 538 nm. Quantitative analysis is performed by observing the linear relationship between the fluorescence intensity ratio I538 / I426 and the curcumin concentration, with a linear range of 10. -9 M to 2×10 -7 M.

8. The method for detecting curcumin and its derivatives according to claim 6, characterized in that, The excitation wavelength of the near-ultraviolet light source is 328 nm.

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