阅读说明：本技术 一种识别和检测草酸的荧光分子探针及其制备方法和应用 (Fluorescent molecular probe for identifying and detecting oxalic acid and preparation method and application thereof ) 是由 贾丽华 郭祥峰 高昕 杨瑞 赵振龙 张宇 于 2020-05-06 设计创作，主要内容包括：一种识别和检测草酸的荧光分子探针及其制备方法和应用,明涉及识别和检测草酸的探针及其制备方法和应用。本发明是要解决现有的利用荧光法识别和检测草酸的荧光探针无法实现定量检测,而且选择性差、易受其它有机酸干扰的技术问题。本发明的荧光分子探针的结构式为：<Image he="739" wi="536" file="DDA0002478475100000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>制法：一、水杨酸、浓硫酸、甲醇反应制备中间体I；二、中间体I与水合肼制备中间体Ⅱ；三、8-羟基喹哪啶、二氧化硒、1,4-二氧六环反应制备中间体Ⅲ；四、中间体Ⅲ与中间体Ⅱ反应得到中间体Ⅳ；五、向中间体Ⅳ与Fe<Sup>3+</Sup>反应,得到探针。它通过荧光增强对草酸进行识别和检测,选择性高且不受其它有机酸的干扰,检出限为1.3×10<Sup>-7</Sup>mol/L。可用于环境、食品领域。(A fluorescent molecular probe for identifying and detecting oxalic acid and a preparation method and application thereof relate to a probe for identifying and detecting oxalic acid and a preparation method and application thereof. The invention aims to solve the technical problems that the existing fluorescent probe for identifying and detecting oxalic acid by using a fluorescence method cannot realize quantitative detection, has poor selectivity and is easy to be interfered by other organic acids. The structural formula of the fluorescent molecular probe is as follows: the preparation method comprises the following steps: firstly, salicylic acid, concentrated sulfuric acid and methanol react to prepare an intermediate I; secondly, preparing an intermediate II by the intermediate I and hydrazine hydrate; reacting the tri-8-hydroxyquinaldine, selenium dioxide and 1, 4-dioxane to prepare an intermediate III; IV, intermediate III and IIIReacting the intermediate II to obtain an intermediate IV; fifthly, adding intermediate IV and Fe 3+ The oxalic acid is identified and detected through fluorescence enhancement, the selectivity is high, the oxalic acid is not interfered by other organic acids, and the detection limit is 1.3 × 10 ‑7 mol/L. Can be used in the fields of environment and food.)

1. A fluorescent molecular probe for identifying and detecting oxalic acid is characterized in that the structural formula of the fluorescent molecular probe is as follows:

2. the method for synthesizing the fluorescent molecular probe for identifying and detecting oxalic acid as claimed in claim 1, which is characterized by comprising the following steps:

firstly, salicylic acid and concentrated sulfuric acid are mixed according to a molar ratio of 1: (0.9-1.5), adding the mixture into methanol, stirring the mixture under the protection of nitrogen, heating the mixture to boiling reflux, and keeping the mixture for 12-18 hours; cooling to room temperature, removing methanol by rotary evaporation, and washing with water for multiple times; extracting with dichloromethane, drying with anhydrous sodium sulfate, and separating with silica gel column chromatography to obtain intermediate I;

secondly, mixing the intermediate I obtained in the first step with hydrazine hydrate in a molar ratio of 1: (2.5-4.5), adding the mixture into ethanol, stirring and heating until boiling and refluxing for reaction for 10.5-13.5 h; spin-drying the reaction solution, and recrystallizing with deionized water to obtain an intermediate II;

thirdly, mixing 8-hydroxyquinaldine and selenium dioxide in a molar ratio of 1: (1.5-2.5) adding the mixture into 1, 4-dioxane, reacting for 6-18 h at the temperature of 95-100 ℃ under the protection of nitrogen, and cooling and standing; filtering, spin-drying the filtrate, and separating by silica gel column chromatography to obtain an intermediate III;

fourthly, mixing the intermediate III obtained in the third step with the intermediate II obtained in the second step in a molar ratio of 1: (1.2-2.5), adding the mixture into ethanol, stirring, heating to boiling, performing reflux reaction for 3.5-4.5 hours, separating out a yellow solid, and washing with ethanol to obtain an intermediate IV;

fifthly, adding the intermediate IV obtained in the fourth step into an organic solvent, and adding Fe with the same molar quantity as the intermediate IV at room temperature³⁺And obtaining the fluorescent molecular probe for identifying and detecting the oxalic acid.

3. The method for synthesizing a fluorescent molecular probe for identifying and detecting oxalic acid according to claim 2, wherein the molar ratio of salicylic acid to concentrated sulfuric acid in the step one is 1: 1.

4. the method for synthesizing a fluorescent molecular probe for identifying and detecting oxalic acid as claimed in claim 2 or 3, wherein in the first step, stirring and heating to boiling reflux are carried out for 13h under the protection of nitrogen.

5. The method for synthesizing a fluorescent molecular probe for identifying and detecting oxalic acid as claimed in claim 2 or 3, wherein the molar ratio of the intermediate I to hydrazine hydrate in the second step is 1: 3.

6. the method for synthesizing a fluorescent molecular probe for identifying and detecting oxalic acid as claimed in claim 2 or 3, wherein the molar ratio of 8-hydroxyquinaldine to selenium dioxide in the step III is 1: 2.

7. the method for synthesizing a fluorescent molecular probe for identifying and detecting oxalic acid as claimed in claim 2 or 3, wherein the molar ratio of the intermediate III to the intermediate II in the fourth step is 1: 2.

8. the method for synthesizing a fluorescent molecular probe for identifying and detecting oxalic acid as claimed in claim 2 or 3, wherein the organic solvent in step five is DMSO, DMF, THF, acetonitrile or a combination of several of the above.

9. The use of the fluorescent molecular probe for the identification and detection of oxalic acid as claimed in claim 1, wherein the fluorescent molecular probe is used for the identification and detection of oxalic acid by fluorescence enhancement.

10. The use of a fluorescent molecular probe for the identification and detection of oxalic acid as claimed in claim 9, wherein the oxalic acid is oxalic acid in rainwater, wastewater, plants or food.

Technical Field

The invention relates to a probe for identifying and detecting oxalic acid, a preparation method and application thereof.

Background

Oxalic acid is a common organic dicarboxylic acid, widely exists in plants, and is particularly high in content in vegetables such as spinach, amaranth and Chinese chives. Oxalic acid taken into a body through diet can form calcium oxalate which is insoluble in water with calcium ions, thereby not only influencing the absorption of calcium in a human body, but also increasing the risk of diseases such as renal calculus and the like. At present, the methods for detecting oxalic acid mainly comprise a titration method, a colorimetric method, a chromatography method and the like. These conventional methods are not only complicated in operation but also have disadvantages such as low sensitivity or high instrument price. As a new detection means, the fluorescent molecular probe has the advantages of high sensitivity, low cost, simple and convenient operation and the like, and is widely concerned. Therefore, it is important to develop a method for detecting oxalic acid using a fluorescent molecular probe. An article entitled oxalate proportional fluorescent probes and living cells imaging based on alkyne conjugated carboxamidoquinoline (aromatic fluorescent probes for oxalate based on alkyl-conjugated carboxamidoquinoline) published by Chunsheng, Qianhong et al in Dalton journal (Dalton Transactions) at 2011, volume 40, page 1034 and 1037 discloses a method for detecting oxalate by using fluorescent molecular probes. However, the molecular probe recognizes and detects oxalic acid through fluorescence quenching, can only detect the oxalic acid qualitatively, and has poor selectivity and is easy to be interfered by other organic acids.

Disclosure of Invention

The invention provides a fluorescent molecular probe for identifying and detecting oxalic acid and a preparation method and application thereof, aiming at solving the technical problems that the existing fluorescent probe for identifying and detecting oxalic acid by using a fluorescence method cannot realize quantitative detection, has poor selectivity and is easily interfered by other organic acids.

The invention relates to a fluorescent molecular probe for identifying and detecting oxalic acid, which has a structural formula as follows:

the fluorescent molecular probe can identify and detect oxalic acid and the content thereof through fluorescence enhancement.

The preparation method of the fluorescent molecular probe for identifying and detecting oxalic acid comprises the following steps:

firstly, salicylic acid and concentrated sulfuric acid are mixed according to a molar ratio of 1: (0.9-1.5), adding the mixture into methanol, stirring the mixture under the protection of nitrogen, heating the mixture to boiling reflux, and keeping the mixture for 12-18 hours; cooling to room temperature, removing methanol by rotary evaporation, and washing with water for multiple times; extracting with dichloromethane, drying with anhydrous sodium sulfate, and separating with silica gel column chromatography to obtain intermediate I;

secondly, mixing the intermediate I obtained in the first step with hydrazine hydrate in a molar ratio of 1: (2.5-4.5), adding the mixture into ethanol, stirring and heating until boiling and refluxing for reaction for 10.5-13.5 h; spin-drying the reaction solution, and recrystallizing with deionized water to obtain an intermediate II;

thirdly, mixing 8-hydroxyquinaldine and selenium dioxide in a molar ratio of 1: (1.5-2.5) adding the mixture into 1, 4-dioxane, reacting for 6-18 h at the temperature of 95-100 ℃ under the protection of nitrogen, and cooling and standing; filtering, spin-drying the filtrate, and separating by silica gel column chromatography to obtain an intermediate III;

fourthly, mixing the intermediate III obtained in the third step with the intermediate II obtained in the second step in a molar ratio of 1: (1.2-2.5), adding the mixture into ethanol, stirring, heating to boiling, performing reflux reaction for 3.5-4.5 hours, separating out a yellow solid, and washing with ethanol to obtain an intermediate IV;

fifthly, adding the intermediate IV obtained in the fourth step into an organic solvent, and adding Fe with the same molar quantity as the intermediate IV at room temperature³⁺And obtaining the fluorescent molecular probe for identifying and detecting the oxalic acid.

The fluorescent molecular probe for identifying and detecting oxalic acid is applied to identifying and detecting oxalic acid by fluorescence enhancement.

The composite fluorescent probe for identifying and detecting oxalic acid can detect the oxalic acid and the content thereof in rainwater, wastewater and plants through fluorescence enhancement, is not interfered by other organic acids, has higher selectivity and sensitivity, and has a detection Limit (LOD) of the probe to the oxalic acid of 1.3 × 10^-7mol/L. The fluorescent probe can be used for detecting the oxalic acid content in environmental samples, foods and other fields, and has wide potential application value.

Drawings

FIG. 1 is a graph showing the change of fluorescence spectrum of the fluorescent molecular probe for identifying and detecting oxalic acid prepared in example 1 before and after the addition of organic acid and amino acid;

FIG. 2 is a bar graph showing the interference between the fluorescence intensity of the fluorescent molecular probe for identifying and detecting oxalic acid prepared in example 1 before and after the addition of organic acid and amino acid and the identification of oxalic acid by other organic acid or amino acid; (in the figure, the letter code numbers correspond to organic acids or amino acids, respectively, (A) blank, (B) L-methionine, (C) L-tryptophan, (D) L-proline, (E) L-arginine, (F) L-aspartic acid, (G) L-phenylalanine, (H) L-threonine, (I) L-serine, (J) L-lysine, (K) L-valine, (L) L-histidine, (M) L-tyrosine, (N) L-leucine, (O) L-cysteine, (P) L-glutamic acid, (Q) citric acid, (R) formic acid, (S) acetic acid, (T) benzoic acid, (U) salicylic acid, (V) tartaric acid, (W) succinic acid, and (X) mandelic acid;

FIG. 3 is a graph showing the change of fluorescence spectra of the fluorescent molecular probe for identifying and detecting oxalic acid prepared in example 1 for different concentrations of oxalic acid;

FIG. 4 is a graph showing the change in fluorescence intensity of the fluorescent molecular probe for identifying and detecting oxalic acid prepared in example 1 for different concentrations of oxalic acid.

Detailed Description