Boronic acid group iridium complex probe, preparation method and application thereof
By targeting and binding polyphenolic substances with iridium borate complex probes, and combining fluorescence spectrophotometry and time-resolved emission spectroscopy, the problem of detecting polyphenolic substances in fruits has been solved. This method achieves highly sensitive and interference-resistant accurate detection, which is suitable for fruit quality assessment and nutritional evaluation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGZHOU WANGLAOJI MAJOR HEALTH IND CO LTD
- Filing Date
- 2025-06-12
- Publication Date
- 2026-05-19
AI Technical Summary
Existing technologies struggle to accurately detect polyphenols in fruits, especially in complex environments where it is difficult to distinguish the target from other fluorophores, leading to detection challenges.
Using iridium borate complex probes, the fluorescence intensity decreases after targeted binding with polyphenolic substances. Detection is achieved by combining fluorescence spectrophotometry and time-resolved emission spectroscopy, thus realizing the quantitative and noise-reduced detection of polyphenolic substances.
It achieves accurate detection of polyphenols, with high sensitivity and anti-interference ability, and is suitable for fruit quality assessment, nutritional evaluation, processing optimization and origin traceability.
Smart Images
Figure CN120289531B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of analytical chemistry, and in particular to a borate group iridium complex probe, its preparation method, and its application. Background Technology
[0002] Polyphenols are an important class of bioactive components in fruits, playing a vital role in their color, taste, and aroma. They also possess various physiological functions and benefits to human health. Their structural characteristic is a benzene ring with two or more hydroxyl groups attached to it. The detection of polyphenols is crucial for fruit quality assessment, nutritional evaluation, processing optimization, variety identification, and origin traceability. However, due to the complexity of the chemical composition of fruits, it is difficult to accurately detect polyphenols.
[0003] Iridium (III) complexes are widely used in optical detection, and probes prepared based on them have the advantages of being non-standard and low-cost. Iridium (III) complex probes have adjustable luminescence lifetimes by connecting different ligands, and can distinguish targets from other fluorophores in complex environments. Therefore, they have potential application value for the detection of polyphenols in fruits. However, in the current technology, the research field of synthesizing and using iridium (III) complex probes to detect polyphenols is still completely blank. Summary of the Invention
[0004] This invention provides a borate group iridium complex probe and its preparation method, which aims to accurately detect polyphenolic substances.
[0005] The borate group iridium complex probe provided by this invention is composed of The precursor is complexed with a PIPB ligand containing a boric acid group to form a structure as shown below:
[0006] .
[0007] The method for preparing the borate group iridium complex probe provided by the present invention includes the following steps:
[0008] Step 1: Synthesize PIPB ligands;
[0009] Phenanthroline-5,6-dione and ammonium acetate were dissolved in glacial acetic acid at a concentration of 0.25 mmol / mL and 5 mmol / mL, respectively. Formylphenylboronic acid was added dropwise at a ratio of 3.5 mmol:10 mL to glacial acetic acid. The reaction mixture was heated at 130 °C for 3 hours under reflux, resulting in a transparent orange-yellow solution. After cooling to room temperature, the mixture was diluted with deionized water, producing a yellow flocculent precipitate. The precipitate was collected by vacuum filtration, washed, air-dried, and recrystallized from anhydrous ethanol to obtain a brown PIPB ligand powder. The structure of the PIPB ligand is shown below.
[0010] ;
[0011] Step 2, The precursor and the PIPB ligand synthesized in step 1 were mixed and dissolved in chloroform / methanol at a ratio of 0.1 mmol:0.3 mmol. The mixture was refluxed at 60 °C for 6 h to obtain an orange-red solution. The solvent in the orange-red solution was removed under reduced pressure to obtain the residue. The residue was purified by silica gel column chromatography using DCM / MeOH at a volume ratio of 20:1 as the eluent. The target band was collected, and the solvent was evaporated to obtain an orange-yellow powder of borate group iridium complex probe.
[0012] The borate group iridium complex probe provided by this invention is used to detect polyphenolic substances.
[0013] Optionally, the detection environment of the borate group iridium complex probe is an acidic environment.
[0014] Optionally, the detection environment pH of the borate group iridium complex probe is 4.4~5.6.
[0015] Optionally, the detection of polyphenols using the borate group iridium complex probe is performed by fluorescence spectrophotometry.
[0016] Optionally, time-resolved emission spectroscopy is used to detect polyphenolic substances using the borate group iridium complex probe.
[0017] The present invention has the following beneficial effects:
[0018] The borate-based iridium complex probe provided by this invention consists of a functional borate-based PIPB ligand and... The precursor complex is formed, enabling targeted recognition of polyphenols. The iridium borate complex probe generates fluorescence of a specific wavelength under excitation at a specific wavelength. After targeted binding with polyphenols, the fluorescence intensity of the sample decreases. Therefore, the fluorescence intensity can be detected by fluorescence spectrophotometry to characterize the content of polyphenols in the sample, achieving quantitative and qualitative detection of polyphenols. In addition, the iridium borate complex probe provided by this invention has a long lifetime. Under high interference intensity, it can achieve targeted noise reduction detection of polyphenols through time-resolved emission spectroscopy, exhibiting extremely high sensitivity. The technical solution of this invention can be applied to the accurate detection of polyphenols in fruits. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0020] Figure 1 The following are fluorescence emission spectra of the borate group iridium complex probes prepared in the embodiments of the present invention under different pH conditions;
[0021] Figure 2 It shows Figure 1 Average intensity of the iridium complex probe with borate group at the optimal emission wavelength under different pH conditions;
[0022] Figure 3 The following are fluorescence emission spectra of the borate group iridium complex probes prepared in the embodiments of the present invention under different epicatechin concentrations.
[0023] Figure 4 It shows Figure 3 The detection limit of epicatechin by a borate group iridium complex probe;
[0024] Figure 5 This is a graph showing the count ratio data of two groups of samples containing and without epicatechin in the TRES noise reduction detection experiment of this invention, using a borate group iridium complex probe and a coumarin mixture.
[0025] Figure 6 It shows Figure 5 In the TRES noise reduction detection experiment shown, at 100 ns, the borate group iridium complex probe and coumarin mixture were used to detect the counts of two groups of samples containing and without epicatechin. Detailed Implementation
[0026] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.
[0027] A first aspect of the present invention provides a borate group iridium complex probe.
[0028] The borate group iridium complex probe (referred to as Ir-PIPB) provided in this embodiment of the invention is composed of... The precursor is complexed with a PIPB ligand containing a boric acid group to form a structure as shown below:
[0029] .
[0030] The borate group iridium complex probe provided in this embodiment of the invention can be prepared by the following steps:
[0031] Step 1: Synthesize PIPB ligands;
[0032] A mixture of phenanthroline-5,6-dione (0.3 g, 2.5 mmol) and ammonium acetate (3.88 g, 50 mmol) was dissolved in glacial acetic acid (10 mL) under vigorous stirring. p-Formylphenylboronic acid (0.525 g, 3.5 mmol) was added dropwise to this solution. The reaction mixture was heated at 130 °C for 3 hours under reflux, during which time the solution turned transparent orange-yellow. After cooling to room temperature, the mixture was diluted with deionized water (100 mL), producing a yellow flocculent precipitate. The yellow flocculent precipitate was collected by vacuum filtration, thoroughly washed with water, air-dried, and then recrystallized from anhydrous ethanol to give a brown PIPB ligand powder (0.53 g, 62% yield).
[0033] The structure of the PIPB ligand is shown below:
[0034] ;
[0035] Step 2, The precursor (110 mg, approximately 0.1 mmol) and the PIPB ligand (105 mg, approximately 0.3 mmol) synthesized in step 1 were mixed and dissolved in chloroform / methanol (10 mL / 10 mL, v / v) solvent. The mixture was refluxed at 60 °C for 6 h to obtain a homogeneous orange-red solution. The solvent in the orange-red solution was removed under reduced pressure to obtain the residue. The residue was purified by silica gel column chromatography using a DCM (dichloromethane) / MeOH (methanol) gradient (20:1, v / v) as the eluent. The target band was collected, and the solvent was evaporated to obtain an orange-yellow powder of iridium borate complex probe (102 mg, yield 58%).
[0036] In a second aspect, the borate group iridium complex probe prepared in the above embodiments is used to detect polyphenolic substances, especially polyphenolic substances in fruits.
[0037] Polyphenols in fruits mainly include flavonoids, hydroxybenzoic acid, hydroxycinnamic acid, catechins, and proanthocyanidins, which play an important role in the color, taste, and aroma of fruits, and also have a variety of physiological functions and benefits to human health.
[0038] To investigate the performance of the prepared borate group iridium complex probe in the detection of polyphenols, the present invention designed the following embodiments.
[0039] Example 1
[0040] This embodiment explores the optimal pH conditions for borate group iridium complex probes.
[0041] The pH of 0.01M PBS (phosphate buffer solution) was adjusted using 0.1mol / L hydrochloric acid or sodium hydroxide solution to obtain the optimal luminescence pH value of Ir-PIPB at different pH values.
[0042] Specifically, an appropriate amount of 0.1 mol / L hydrochloric acid or sodium hydroxide solution was added to 0.01 M PBS to obtain PBS solutions with pH values of 4.4, 5.0, 5.6, 6.2, 6.8, 7.4, 8.0, and 8.6, respectively. 40 μM Ir-PIPB / DMSO (a dimethyl sulfoxide solution of Ir-PIPB, with an Ir-PIPB concentration of 40 μM) was diluted with PBS solutions of different pH values to obtain DMSO-PBS solutions with a DMSO volume fraction of 2%. The above solutions were excited to fluorescence at a wavelength of 405 nm, and the fluorescence intensity was detected using a fluorescence spectrophotometer, scanning within the emission wavelength range of 450-750 nm.
[0043] Test results as follows Figure 1 and Figure 2As shown, Ir-PIPB exhibits strong fluorescence in the pH range of 4.4 to 5.6; as the pH increases, the fluorescence intensity of Ir-PIPB decreases, indicating that it has the characteristics of an acidic probe and is suitable for the detection of functional polyphenols in acidic fruit juices such as lychee, prickly pear, and plum.
[0044] Example 2
[0045] To evaluate the detection capability of Ir-PIPB for 1,2-dihydroxybenzene compounds (a class of polyphenols), epicatechin, a representative compound from litchi, was selected as the target analyte under the optimal pH conditions of the probe.
[0046] At pH 5, a mixed solution of probe and standard substance (epicatechin standard solution) in 2% DMSO-PBS buffer was prepared. The concentration of Ir-PIPB in the mixed solution was set to 40 μM, and the concentrations of the standard substance were set as follows: 0, 1, 2.5, 5, 10, 20, 50, 100, 200, 400, and 800 μM. After incubation at room temperature for 30 minutes, the final solution was excited to fluorescence at a wavelength of 405 nm, and the fluorescence intensity was detected using a fluorescence spectrophotometer, scanning within the emission wavelength range of 450-750 nm.
[0047] Test results as follows Figure 3 and Figure 4 As shown, even when the epicatechin content is 1 μM, the fluorescence intensity of Ir-PIPB is significantly reduced, indicating that the Ir-PIPB provided in this embodiment of the invention has excellent sensitivity in detecting epicatechin. As the epicatechin content increases, the fluorescence intensity of Ir-PIPB gradually decreases, enabling quantitative analysis of epicatechin.
[0048] Example 3
[0049] In this embodiment, to evaluate the noise reduction detection capability of Ir-PIPB for 1,2-dihydroxybenzene compounds under complex conditions, TRES noise reduction was used to detect epicatechin in an interfering environment.
[0050] Specifically, a 40 μM Ir-PIPB probe and a 100 μM interference probe (coumarin) were prepared in a 2% DMSO-PBS solution as noise reduction detection targets. Samples containing and without an 8 μM epicatechin standard were tested respectively. Finally, the solution was excited to fluorescence at a wavelength of 405 nm, and time-resolved emission spectroscopy was performed at emission wavelengths of 500-700 nm with a step size of 10 nm.
[0051] The principle of Time-Resolved Emission Spectroscopy (TRES) is as follows: When a substance is excited, molecules in the excited state will return to the ground state by emitting fluorescence or phosphorescence; different fluorescent substances have different fluorescence lifetimes, which are the average times that excited-state molecules remain in the excited state; TRES technology uses pulsed lasers or flash sources to instantaneously excite the sample, and then measures the fluorescence spectrum emitted by the sample at different time delays; in this way, components with different fluorescence lifetimes can be distinguished, and information on fluorescence spectra that change over time can be obtained.
[0052] Experimental results are as follows Figure 5 and Figure 6 As shown, two groups of samples, one containing epicatechin and the other without, were compared. A significant increase in the count ratio was observed in the 1-100 ns range, peaking at 100 ns before gradually decreasing. This indicates that Ir-PIPB possesses a long lifetime (generally, exogenous fluorescent substances have short luminescence lifetimes and decay quickly). By applying TRES detection, Ir-PIPB leverages its long luminescence lifetime to significantly reduce interference from exogenous fluorescent substances, improving detection accuracy and specificity. Furthermore, the noise reduction effect of Ir-PIPB reaches its optimal level at 100 ns.
[0053] Furthermore, a comparison with the results of detecting epicatechin content using conventional fluorescence spectrophotometry in Example 2 reveals that, compared to conventional fluorescence spectrophotometry, TRES, when detecting the same amount of epicatechin, still showed a 9.3-fold reduction in fluorescence intensity even under the influence of 2.5 times the coumarin interference concentration, while the fluorescence intensity detected by conventional fluorescence spectrophotometry only decreased by about 1.7 times. This indicates that by utilizing the long lifetime characteristics of Ir-PIPB, the detection sensitivity for polyphenolic substances can be further improved even under high interference intensity.
[0054] In summary, the borate-based iridium complex probe provided in this embodiment of the invention consists of a functional borate-based PIPB ligand and... The precursor complex is formed to achieve targeted recognition of polyphenols. The borate group iridium complex probe generates fluorescence of a certain wavelength under specific wavelength excitation. After targeted binding with polyphenols, the fluorescence intensity of the sample decreases. Therefore, the fluorescence intensity can be detected by fluorescence spectrophotometry to characterize the content of polyphenols in the sample, realizing quantitative and qualitative detection of polyphenols. In addition, the borate group iridium complex probe provided by this invention has a long lifetime. Under high interference intensity, it can achieve targeted noise reduction detection of polyphenols through time-resolved emission spectroscopy, with extremely high sensitivity.
[0055] The borate group iridium complex probe provided in this invention is suitable for the accurate detection of polyphenols in fruits and plays an important role in fruit quality assessment, nutritional evaluation, processing technology optimization, variety identification, and origin traceability.
[0056] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.
Claims
1. A borate-based iridium complex probe, characterized in that, It is formed by the complexation of the [Ir(ppy)2Cl]2 precursor and the PIPB ligand with a boric acid group, and the structure is shown below: 。 2. A method for preparing the iridium borate complex probe according to claim 1, characterized in that, Includes the following steps: Step 1: Synthesize PIPB ligands; A mixture of phenanthroline-5,6-dione and ammonium acetate was dissolved in glacial acetic acid. p-Formylphenylboronic acid was added dropwise, and the reaction mixture was heated at 130°C for 3 hours under reflux. The solution turned a transparent orange-yellow color. After cooling to room temperature, the mixture was diluted with deionized water, producing a yellow flocculent precipitate. The yellow flocculent precipitate was collected by vacuum filtration, washed, air-dried, and recrystallized with anhydrous ethanol to obtain a brown PIPB ligand powder. The structure of the PIPB ligand is shown below: ； Step 2: The [Ir(ppy)2Cl]2 precursor and the PIPB ligand synthesized in Step 1 were mixed and dissolved in chloroform / methanol solvent and refluxed at 60°C for 6 h to obtain an orange-red solution. The solvent in the orange-red solution was removed under reduced pressure to obtain the residue. The residue was purified by silica gel column chromatography to collect the target band. After evaporating the solvent, an orange-yellow powder of borate group iridium complex probe was obtained.
3. The method for preparing the iridium borate complex probe according to claim 2, characterized in that, In step 1, phenanthroline-5,6-dione and ammonium acetate are mixed and dissolved in glacial acetic acid, with the concentration of phenanthroline-5,6-dione being 0.25 mmol / mL and the concentration of ammonium acetate being 5 mmol / mL.
4. The method for preparing the iridium borate complex probe according to claim 2, characterized in that, In step 1, the ratio of formylphenylboronic acid to glacial acetic acid is 3.5 mmol: 10 mL.
5. The method for preparing the iridium borate complex probe according to claim 2, characterized in that, In step 2, the ratio of the [Ir(ppy)2Cl]2 precursor to the PIPB ligand is 0.1 mmol: 0.3 mmol.
6. The method for preparing the iridium borate complex probe according to claim 2, characterized in that, In step 2, silica gel column chromatography purification uses a DCM / MeOH elution buffer with a volume ratio of 20:
1.
7. The application of the borate group iridium complex probe according to claim 1 or the borate group iridium complex probe prepared by any one of claims 2-6 in the detection of polyphenols, wherein the polyphenol is epicatechin.
8. The application according to claim 7, characterized in that, The detection environment of the borate group iridium complex probe is an acidic environment.
9. The application according to claim 7, characterized in that, The detection of polyphenols using the borate group iridium complex probe was performed by fluorescence spectrophotometry.
10. The application according to claim 7, characterized in that, The borate group iridium complex probe was used to detect polyphenols using time-resolved emission spectroscopy.