Porous covalent triazine framework materials, porous covalent triazine framework material solid-phase microextraction probes, and methods of making and using the same

Abstract

The application discloses a kind of porous covalent triazine framework materials, porous covalent triazine framework material solid-phase microextraction probe and its preparation method and application, belong to solid-phase microextraction technical field;The porous covalent triazine framework material provided by the application has the characteristics of good thermal stability, large specific surface area, rich pore structure, high pore uniformity, when it is used as the coating layer of solid-phase microextraction and the probe prepared is used for in-situ extraction and non-target qualitative analysis on different growth period vegetables in-vivo nutrient, there is strong intersegment hydrogen bond interaction, electrostatic attraction and π-π stacking effect between it and different physicochemical properties of nutrient in the body of vegetable, that is, it has excellent adsorption capacity to the nutrient with complex structure in the body of vegetable, and has excellent adsorption capacity.Meanwhile, the preparation method of the porous covalent triazine framework material, the porous covalent triazine framework material solid-phase microextraction probe provided by the application is simple to operate, and is beneficial to actual production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid phase microextraction, and particularly relates to a porous covalent triazine skeleton material, a porous covalent triazine skeleton material solid phase microextraction probe and a preparation method and application thereof. BACKGROUND

[0002] Endogenous metabolites are important components in organisms with rich physiological and biological functions, especially compounds related to special aroma characteristics, which have been widely used in food safety evaluation, freshness evaluation, nutritional substance evaluation and food variety identification. It is of great application value in food and agricultural science to establish an in-situ, rapid and non-target qualitative analysis method for nutritional substances (endogenous metabolites) in vegetables.

[0003] Sample pretreatment technology is the basis of analysis method, which greatly affects the time resolution and accuracy of food analysis. So far, previous studies on the detection of endogenous substances in agricultural products mostly use traditional solvent extraction methods to analyze excised tissues of edible animals or plants, but the ex situ sampling and solvent extraction method is not only time-consuming and laborious, but also leads to the loss of unstable and short-lived metabolites in the sample pretreatment process. For example, in previous studies, cruciferous vegetable tissues were excised and pretreated by solvent extraction, headspace adsorption or using commercial SPME probes (PDMS probes), and then the nutritional substance components or endogenous metabolites in the vegetables were analyzed by instruments; but these nutritional substances or metabolites are obtained by ex situ analysis of plant tissue samples, which easily leads to the loss and structural changes of some active substances and endogenous metabolites during the preparation of plant tissues. In contrast, non-destructive solid phase microextraction in-situ sampling method can minimize the disturbance to the organism, and can track the individual organism for a long time, which can not only reduce the loss of plant samples in the study, but also avoid the influence of individual differences.

[0004] Solid phase microextraction in-situ sampling provides a good solution for in-situ, rapid and non-target qualitative analysis of nutritional substances (endogenous metabolites) in vegetables. The extraction coating is the core of solid phase microextraction technology, and the application of in-situ solid phase microextraction sampling method depends on the development and preparation of coating materials. Although some solid phase microextraction coatings have been commercialized, these commercial probes have the disadvantages of high price and unsatisfactory broad-spectrum extraction performance, which limits the application of in-vivo SPME sampling technology. Therefore, it is of great significance to develop a new type of solid phase microextraction probe with broad-spectrum extraction performance and low price. SUMMARY

[0005] The present application aims to overcome the deficiencies of the prior art and provide a porous covalent triazine framework material, a porous covalent triazine framework material solid-phase microextraction probe, and a preparation method and application thereof.

[0006] To achieve the above-mentioned object, in a first aspect of the present application, the present application provides a preparation method of a porous covalent triazine framework material, comprising the following steps:

[0007] Mixing cyanuric chloride and DMSO to obtain solution A;

[0008] Mixing melamine, alkali metal hydroxide and DMSO to obtain solution B;

[0009] Stirring solution B under inert gas environment at-5-0℃ and adding solution A dropwise, heating the reaction after the addition is completed, centrifuging, washing and drying after the reaction is completed to obtain the porous covalent triazine framework material.

[0010] The present application provides a porous covalent triazine framework material, which is prepared by selecting the above-mentioned raw materials and preparation method. The porous covalent triazine framework material has the characteristics of good thermal stability, large specific surface area, rich pore structure and high uniformity of pores. The structure of the porous covalent triazine framework material prepared by the preparation method of the present application has rich amino groups and rich conjugate bonds. When the prepared porous covalent triazine framework material is further used as a coating layer of solid-phase microextraction for in-situ extraction of nutrients in different growth period vegetables and non-target qualitative analysis, it can have strong inter-segment hydrogen bond interaction, electrostatic attraction and π-π stacking effect with nutrients in vegetables with different physicochemical properties, that is, it has excellent adsorption capacity for nutrients in vegetables with complex structure and excellent adsorption capacity.

[0011] As a preferred embodiment of the preparation method of the present application, in solution A, the molar volume ratio of cyanuric chloride to DMSO is cyanuric chloride:DMSO=5mmol:(48-52)mL; in solution B, the molar volume ratio of melamine, alkali metal hydroxide and DMSO is melamine:alkali metal hydroxide:DMSO=5mmol:10mmol:(48-52)mL.

[0012] The inventors have found that when the molar volume ratio of the substances in solution A and solution B is further optimized within the above-mentioned range, the specific surface area of the obtained porous covalent triazine framework material can be larger and the pores can be more uniform.

[0013] Preferably, the alkali metal hydroxide includes potassium hydroxide or sodium hydroxide.

[0014] The inventors have found that, by selecting alkali hydroxide as the alkaline reagent, the alkali hydroxide plays the role of acid-binding agent, can neutralize the hydrochloric acid generated by cyanuric chloride + melamine, and can promote the reaction to proceed in a positive direction, so that the porous covalent triazine skeleton material with a higher specific surface area and a smaller average pore size is obtained. When the alkali hydroxide is further selected as potassium hydroxide or sodium hydroxide, the comprehensive effect of the obtained material is better.

[0015] As a preferred embodiment of the preparation method of the present application, the temperature of the heating reaction is 150-165℃, and the time of the heating reaction is 24-26h.

[0016] The inventors have found that, when the temperature and time of the heating reaction are further optimized within the above ranges, the specific surface area of the obtained porous covalent triazine skeleton material is larger, the pores are more uniform, and the content of amino groups and conjugate bonds in the structure is more.

[0017] As a preferred embodiment of the preparation method of the present application, the inert gas environment is nitrogen or a noble gas environment.

[0018] As a preferred embodiment of the preparation method of the present application, the speed of the dropwise addition is 8-12mL / min.

[0019] As a preferred embodiment of the preparation method of the present application, the washing is washing with methanol and water for 2-3 times, respectively.

[0020] As a preferred embodiment of the preparation method of the present application, the drying is drying in a vacuum drying oven at 75-85℃ for 12-16h.

[0021] The porous covalent triazine skeleton material prepared by the present application is in the form of white powder, and is stored at room temperature in the dark after preparation.

[0022] In the second aspect of the present application, the present application provides a porous covalent triazine skeleton material, which is prepared by the preparation method of the present application.

[0023] The porous covalent triazine skeleton material provided by the present application has the characteristics of good thermal stability, large specific surface area, rich pore structure, and high pore uniformity, and the structure of the porous covalent triazine skeleton material prepared by the preparation method of the present application has rich amino groups and rich conjugate bonds. Specifically, the specific surface area of the porous covalent triazine skeleton material provided by the present application is 500m 2 / g or more, and the pore size distribution value is between 1.2-1.5nm.

[0024] In the third aspect of the present application, the present application provides the use of the porous covalent triazine skeleton material in the preparation of a porous covalent triazine skeleton material solid-phase microextraction probe.

[0025] In a fourth aspect of the present application, the present application provides a porous covalent triazine framework material solid-phase microextraction probe, which comprises a stainless steel wire and a surface coating coated on the stainless steel wire, and the material of the surface coating is the porous covalent triazine framework material described in the present application.

[0026] The porous covalent triazine framework material solid-phase microextraction probe provided by the present application can be used for in-situ extraction and non-target qualitative analysis of nutrients in vegetables in different growth periods. The probe can have strong inter-segment hydrogen bond interaction, electrostatic attraction and π-π stacking effect with nutrients in vegetables with different physicochemical properties, that is, the probe has excellent adsorption capacity for nutrients in vegetables with complex structures, and has excellent adsorption capacity.

[0027] As a preferred embodiment of the porous covalent triazine framework material solid-phase microextraction probe, the diameter of the stainless steel wire is 127 μm, and the length is 3-4 cm; the length of the surface coating is 0.8-1.2 cm, and the thickness is 10-40 μm.

[0028] The inventors have found that when the parameters in the porous covalent triazine framework material solid-phase microextraction probe are within the above range, the extraction enrichment capacity of the solid-phase microextraction probe can be better realized.

[0029] In a fifth aspect of the present application, the present application provides a preparation method of the porous covalent triazine framework material solid-phase microextraction probe, which comprises the following steps:

[0030] Mixing and stirring silicone glue and o-xylene to obtain an adhesive solution;

[0031] Placing the pretreated stainless steel wire in the adhesive solution, then taking out and absorbing the adhesive solution on the surface of the stainless steel wire, then coating the porous covalent triazine framework material on the surface of the stainless steel wire, and after coating, solidifying at 115-125℃ for 20-30 min, repeating the coating-solidifying process, and after the last coating-solidifying is completed, aging at 240-260℃ for 50-70 min in an inert gas environment to obtain the porous covalent triazine framework material solid-phase microextraction probe.

[0032] The preparation method provided by the present application utilizes the adhesion of the silicone adhesive solution, and the porous covalent triazine skeleton material solid-phase microextraction probe is prepared by a direct coating method, and the preparation method is simple; and the main component of the silicone adhesive is polydimethylsiloxane which has good biocompatibility and heat resistance, so that the porous covalent triazine skeleton material solid-phase microextraction probe prepared on the basis of the porous covalent triazine skeleton material which can help to realize excellent adsorption capacity of the porous covalent triazine skeleton material solid-phase microextraction probe also has good biocompatibility and heat resistance, and completely meets the application requirements of subsequent in-situ extraction of nutrients in vegetables and analysis of thermal desorption instruments.

[0033] As a preferred embodiment of the preparation method of the present application, the mass-volume ratio of the silicone adhesive and o-xylene is (0.4-0.6) g / mL.

[0034] The inventors have found that when the mass-volume ratio of the silicone adhesive and o-xylene is in the above range, the silicone adhesive can be dispersed into a viscous glue liquid, forming an adhesive solution with better adhesion effect, which helps the subsequent coating of the porous covalent triazine skeleton material.

[0035] As a preferred embodiment of the preparation method of the present application, the pretreatment is to sequentially immerse the stainless steel wire in ultrapure water, methanol and n-hexane, and then take out and dry at room temperature to obtain the pretreated stainless steel wire.

[0036] The pretreatment process can well clean the surface of the stainless steel wire, which is beneficial to the subsequent coating of the porous covalent triazine skeleton material.

[0037] As a preferred embodiment of the preparation method of the present application, the number of repetitions of the coating-curing process is 1-3 times, until the thickness of the surface coating layer is 10-40 μm.

[0038] In a sixth aspect of the present application, the present application provides the application of the porous covalent triazine skeleton material solid-phase microextraction probe in in-situ extraction and non-target qualitative analysis of nutrients in different growth period vegetables.

[0039] Compared with the prior art, the present application has the following advantages:

[0040] The porous covalent triazine framework material has the characteristics of good thermal stability, large specific surface area, rich pore structure and high pore uniformity. When the porous covalent triazine framework material solid-phase microextraction probe prepared by taking the porous covalent triazine framework material as a solid-phase microextraction coating is used for in-situ extraction and non-target qualitative analysis of nutrients in different growth period vegetables, the strong inter-segment hydrogen bond interaction, electrostatic attraction and π-π stacking effect between the porous covalent triazine framework material solid-phase microextraction probe and the nutrients in the vegetables with different physicochemical properties can be achieved, that is, the porous covalent triazine framework material solid-phase microextraction probe has excellent adsorption capacity for the nutrients in the vegetables with complex structure. At the same time, the porous covalent triazine framework material solid-phase microextraction probe also contains a silicone adhesive, the main component of the silicone adhesive is polydimethylsiloxane which has good biocompatibility and heat resistance, and the prepared porous covalent triazine framework material solid-phase microextraction probe has good biocompatibility and heat resistance, which fully meets the application requirements of in-situ extraction and thermal desorption instrument analysis. In the in-situ extraction and non-target qualitative analysis of nutrients in different growth period vegetables by using the porous covalent triazine framework material solid-phase microextraction probe, the extraction time is short, the types of extracted non-target vegetable nutrients are comprehensive, and the extracted substances are more. Moreover, the porous covalent triazine framework material and the preparation method of the porous covalent triazine framework material solid-phase microextraction probe provided by the present application are simple to operate, which is beneficial to actual production. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a structural schematic diagram of the porous covalent triazine framework material prepared in Example 1;

[0042] Figure 2 is a Fourier transform infrared spectroscopy (FT-IR) characterization diagram of the porous covalent triazine framework material prepared in Example 1;

[0043] Figure 3 is a pore size distribution diagram of the porous covalent triazine framework material prepared in Example 1;

[0044] Figure 4 is a scanning electron microscope diagram of the solid-phase microextraction probe prepared in Example 6;

[0045] Figure 5 is a principal component analysis (PCA) diagram of nutrients in the same batch of small cabbages with different growth periods (the growth periods are 3 weeks, 4 weeks and 5 weeks, respectively) provided by the solid-phase microextraction probe prepared in Example 6. DETAILED DESCRIPTION

[0046] For better purposes, technical solutions and advantages of the present application, the present application will be further described below in combination with specific examples.

[0047] The reagents, methods and devices used in the present application are conventional reagents, methods and devices in the art unless otherwise specified; and the raw materials used in parallel experiments are the same batch of raw materials unless otherwise specified.

[0048] Example 1

[0049] The present application provides a porous covalent triazine-based material, and a preparation method of the porous covalent triazine-based material is as follows:

[0050] (1) Mix cyanuric chloride (0.922 g, 5 mmol) and anhydrous DMSO (50 mL) to obtain solution A;

[0051] (2) Mix melamine (0.630 g, 5 mmol), potassium hydroxide (0.561 g, 10 mmol) and anhydrous DMSO (50 mL) to obtain solution B;

[0052] (3) Place solution B in an ice bath under N2 environment and stir vigorously, drop solution A at a speed of 10 mL / min during the vigorous stirring, after the dropping is completed, heat the mixture to 160℃ to reflux for 24 h, after the reaction is completed, centrifuge, collect the product after centrifugation, wash with methanol and water for 3 times in turn, and finally dry the product in a vacuum drying oven at 80℃ for 12 h to obtain a white powdery porous covalent triazine-based material.

[0053] Example 2

[0054] The present application provides a porous covalent triazine-based material, and a preparation method of the porous covalent triazine-based material is as follows:

[0055] Example 3

[0056] The present application provides a porous covalent triazine-based material, and a preparation method of the porous covalent triazine-based material is as follows:

[0057] Example 4

[0058] The present application provides a porous covalent triazine-based material, and a preparation method of the porous covalent triazine-based material is as follows:

[0059] Example 5

[0060] The embodiment of the present application provides a porous covalent triazine skeleton material, and the only difference between the preparation method of the porous covalent triazine skeleton material and the embodiment 1 is that potassium hydroxide is replaced by sodium hydroxide.

[0061] Comparative example 1

[0062] The comparative example of the present application provides a porous covalent triazine skeleton material, and the preparation method of the porous covalent triazine skeleton material is as follows:

[0063] After tricyanoyl chloride (0.922g, 5mmol), melamine (0.630g, 5mmol), potassium hydroxide (0.561g, 10mmol) and anhydrous DMSO (100mL) are mixed, the mixture is heated to 160℃ and refluxed for 24h, after the reaction is completed, centrifugation is carried out, the product after centrifugation is collected, washed with methanol and water for three times respectively, and finally the product is placed in a vacuum drying box at 80℃ and dried for 12h, to obtain a white powder of the porous covalent triazine skeleton material.

[0064] Comparative example 2

[0065] The comparative example of the present application provides a porous covalent triazine skeleton material, and the only difference between the preparation method of the porous covalent triazine skeleton material and the embodiment 1 is that solution B is placed at room temperature under N2 environment and stirred intensively.

[0066] Comparative example 3

[0067] The comparative example of the present application provides a porous covalent triazine skeleton material, and the only difference between the preparation method of the porous covalent triazine skeleton material and the embodiment 1 is that tricyanoyl chloride is replaced by tricyamide.

[0068] Embodiment 6

[0069] The embodiment of the present application provides a porous covalent triazine skeleton material solid-phase microextraction probe, and the preparation method of the porous covalent triazine skeleton material solid-phase microextraction probe comprises the following steps:

[0070] (1) a stainless steel wire with a diameter of 127μm and a length of 3cm is sequentially immersed in ultrapure water, methanol and n-hexane for ultrasonic treatment for 30min, and then taken out and dried at room temperature to obtain a pretreated stainless steel wire;

[0071] (2) 0.5g of silicone glue is mixed with 1.0mL of o-xylene, and then ultrasonically treated for 15min to obtain an adhesive solution;

[0072] (3) the front end of the pretreated stainless steel wire is inserted into the adhesive solution for 1cm, and then taken out, and the liquid drops visible on the surface of the stainless steel wire are wiped with filter paper to obtain a stainless steel wire coated with an extremely thin silicone glue coating;

[0073] (4) Put the stainless steel wire coated with a very thin layer of silicone glue on the porous covalent triazine framework material prepared in Example 1 and roll, get the stainless steel wire coated with a layer of porous covalent triazine framework material, use the serrated part of the tip of the tweezers to rub the part of the stainless steel wire which is not coated with material, so that the material which is not firmly adhered falls off the stainless steel wire, and place it in an oven for curing, the curing temperature is 120°C, and the curing time is 30 min;

[0074] (5) Repeat step (4) until the coating thickness is 25 μm; then age the obtained product at 250°C for 60 min under nitrogen protection, get the porous covalent triazine framework material solid-phase microextraction probe, then insert the porous covalent triazine framework material solid-phase microextraction probe into the SPME sleeve.

[0075] The scanning electron microscope image of the porous covalent triazine framework material solid-phase microextraction probe prepared in the embodiment of the present application is shown in Figure 4 .

[0076] Example 7

[0077] The embodiment of the present application provides a porous covalent triazine framework material solid-phase microextraction probe, and the only difference between the preparation method of the porous covalent triazine framework material solid-phase microextraction probe and that of Example 6 is that the porous covalent triazine framework material used is the porous covalent triazine framework material prepared in Example 2.

[0078] Example 8

[0079] The embodiment of the present application provides a porous covalent triazine framework material solid-phase microextraction probe, and the only difference between the preparation method of the porous covalent triazine framework material solid-phase microextraction probe and that of Example 6 is that the porous covalent triazine framework material used is the porous covalent triazine framework material prepared in Example 3.

[0080] The embodiment of the present application provides a porous covalent triazine framework material solid-phase microextraction probe, and the only difference between the preparation method of the porous covalent triazine framework material solid-phase microextraction probe and that of Example 6 is that the porous covalent triazine framework material used is the porous covalent triazine framework material prepared in Example 4.

[0081] Example 10

[0082] The embodiment of the present application provides a porous covalent triazine framework material solid-phase microextraction probe, and the only difference between the preparation method of the porous covalent triazine framework material solid-phase microextraction probe and that of Example 6 is that the porous covalent triazine framework material used is the porous covalent triazine framework material prepared in Example 5.

[0083] Example 11

[0084] The embodiment of the present application provides a porous covalent triazine-based framework material solid-phase microextraction probe, and the only difference between the preparation method of the porous covalent triazine-based framework material solid-phase microextraction probe and the embodiment 6 is that the coating thickness is 40 μm.

[0085] Embodiment 12

[0086] The embodiment of the present application provides a porous covalent triazine-based framework material solid-phase microextraction probe, and the only difference between the preparation method of the porous covalent triazine-based framework material solid-phase microextraction probe and the embodiment 6 is that the coating thickness is 10 μm.

[0087] Embodiment 13

[0088] The embodiment of the present application provides a porous covalent triazine-based framework material solid-phase microextraction probe, and the only difference between the preparation method of the porous covalent triazine-based framework material solid-phase microextraction probe and the embodiment 6 is that 1 g of silicone glue is mixed with 1.0 mL of o-xylene and stirred uniformly.

[0089] Embodiment 14

[0090] The embodiment of the present application provides a porous covalent triazine-based framework material solid-phase microextraction probe, and the only difference between the preparation method of the porous covalent triazine-based framework material solid-phase microextraction probe and the embodiment 6 is that 0.1 g of silicone glue is mixed with 1.0 mL of o-xylene and stirred uniformly.

[0091] Effect example 1

[0092] The performance parameters of the porous covalent triazine-based framework materials prepared from the embodiment 1-5 and the comparative examples 1-3 of the present application are tested, wherein the specific surface area and porosity are characterized by nitrogen adsorption experiments, and the obtained results are shown in Table 1.

[0093] Table 1

[0094]

[0095] As can be seen from Table 1, the porous covalent triazine-based framework material prepared by the preparation method of the present application has a large specific surface area and a small average pore size, wherein the specific surface area is 500 m 2 g -1 The above average pore size is below 1.5 nm, which indicates that the porous covalent triazine-based framework material prepared by the present application has great potential as a high-performance adsorbent.

[0096] From the example 1 and the example 2-3, it can be seen that the ratio of raw materials to solvents in the preparation of the porous covalent triazine skeleton material will affect the specific surface area and pore size of the product; from the example 1 and the example 4, it can be seen that the reaction temperature in the preparation of the porous covalent triazine skeleton material will also affect the performance of the product, when the heating reaction temperature is not in the further preferred range, compared with the example 1, the specific surface area of the obtained product is decreased by 25.37%, and the average pore size is increased by 25%; from the example 1 and the example 5, it can be seen that the type of raw materials used will also affect the performance of the product; from the example 1 and the comparative example 1-2, it can be seen that when the dropwise adding method is not used or the dropwise adding temperature is not in the range given by the present application, the reaction will be particularly violent, which will cause safety problems and is not suitable for preparation; from the example 1 and the comparative example 3, it can be seen that when other substances are used to replace the raw materials in the present application, the corresponding porous covalent triazine material cannot be obtained.

[0097] The structure of the porous covalent triazine skeleton material prepared in the example 1 is shown in Figure 1 The functional groups in the structure of the porous covalent triazine skeleton material prepared in the example 1 were further characterized by Fourier transform infrared spectroscopy (FT-IR), and the results are shown in Figure 2 The absorption peak at 1351 cm -1 -1 belongs to the stretching vibration of C-N-C, the absorption peak at 3406 cm -1 -1 belongs to the -NH- group in the aggregate state in the material, the absorption peak at 1553 cm -1 -1 is from the coupling peak of the stretching vibration of C=N and the bending vibration of -NH-, the absorption peak at 814 cm -1 -1 is caused by the deformation vibration of the triazine ring, and the FT-IR spectroscopy characterization results are in good agreement with the structure of the porous covalent triazine skeleton material; in addition, the pore size distribution diagram of the porous covalent triazine skeleton material prepared in the example 1 is shown in Figure 3 From the Figure 3 , it can be seen that the pore size of the porous covalent triazine skeleton material prepared by the technical scheme of the present application is relatively uniform.

[0098] Example 2

[0099] The porous covalent triazine framework material solid-phase microextraction probe prepared in the effect example test embodiment 6-14 and the solid-phase microextraction probe prepared in the prior art (CN113413639B) are used to test the extraction performance of the nutrients in the vegetables, and the specific steps include the following: the porous covalent triazine framework material solid-phase microextraction probe prepared in the embodiment 6-14 and the solid-phase microextraction probe in the prior art are stabbed into the stems of the same vegetable to perform in vivo in-situ sampling for 30 min, extraction, the extracted probe is directly placed in the GC-QTOF-MS desorption port for thermal desorption and detection, the non-targeted nutrients in the vegetable are extracted and analyzed, according to the analysis results of the GC-QTOF-MS, the components with low matching degree and the components lost from the chromatographic column are removed, and the total detected substance types of the solid-phase microextraction probe are counted; then, the detected substances are qualitatively analyzed by using the triple information of the retention index, the accurate molecular weight and the NIST matching library, the qualitative rules include: (1) the NIST spectrum library forward / reverse matching degree > 65; (2) the error between the measured accurate molecular weight and the theoretical molecular weight is ≤0.00002%; (3) the error between the measured retention index and the theoretical retention index is ≤40, and the finally identified endogenous plant metabolite types are given; the obtained results are shown in Table 2.

[0100] Table 2

[0101]

[0102] As can be seen from Table 2, the porous covalent triazine framework material solid-phase microextraction probe prepared by the preparation method of the present application has great adsorption capacity and adsorption ability, especially when the porous covalent triazine framework material prepared in the embodiments 1-3 and 5 of the present application is further preferred, and the thickness of the porous covalent triazine framework material is 25-40 μm, and the mass / volume ratio of the silicone glue and o-xylene is (0.4-0.6) g / mL, the number of identified endogenous plant metabolites of the obtained solid-phase microextraction probe is more than 84, compared with the prior art, the number of identified endogenous plant metabolites is significantly increased; that is, the enrichment and extraction ability of the porous covalent triazine framework material solid-phase microextraction probe provided by the present application is more excellent; further analysis of the substances enriched by the porous covalent triazine framework material solid-phase microextraction probe in the embodiment 6 and the prior art probe finds that among the 100 Brassica chinensis metabolites identified by using the porous covalent triazine framework material solid-phase microextraction probe in the embodiment 6, 49 metabolites are not extracted in vivo by the prior art probe, which further illustrates that compared with the prior art, the enrichment and extraction ability of the porous covalent triazine framework material solid-phase microextraction probe of the present application for non-targeted metabolites in vegetables is more excellent.

[0103] The principal component analysis (PCA) graph of the same batch of pakchoi of different growth periods (3 weeks, 4 weeks, 5 weeks of age, respectively) provided by the porous covalent triazine skeleton material solid-phase microextraction probe prepared in Example 6 is shown in Figure 5 As shown, further analysis of the endogenous plant metabolites finally detected by the porous covalent triazine skeleton material solid-phase microextraction probe in Example 6 is shown in Table 3. As can be seen from Table 3, the detected endogenous plant metabolites mainly include aldehydes, ketones, acids, alcohols, phenols, alkanes, alkenes, esters, isothiocyanates, nitriles, indoles and derivatives thereof, etc. As can be seen from Table 3, among the 100 substances identified by the porous covalent triazine skeleton material solid-phase microextraction probe prepared in Example 6 for in vivo sampling of vegetables, more than 70 endogenous metabolites have not been detected in the previously published in vitro analysis methods of vegetable tissues. In particular, dozens of endogenous ketone substances detected by the porous covalent triazine skeleton material solid-phase microextraction probe prepared in Example 6, such as furanones, pyranones, phenyl-substituted ketones, and heterocyclic-substituted ketones, are rarely reported in previous in vitro analysis studies. At the same time, as can be seen from Table 3, eight thioglucoside hydrolysis products (i.e. isothiocyanates and nitriles) are also detected from the in vivo pakchoi. These products are believed to be the source of the potential anticancer properties of cruciferous vegetables. These detected isothiocyanates and nitriles include isopropyl isothiocyanate, 2-butyl isothiocyanate, 4-butene isothiocyanate, phenethyl isothiocyanate, benzyl nitrile, phenylpropyl nitrile, 1H-indole-3-acetonitrile, and 4-methoxyindole-3-acetonitrile, proving that the porous covalent triazine skeleton material solid-phase microextraction probe combined with GC-QTOF-MS analysis can provide rich information of vegetable nutrients / endogenous metabolites, which has important value in agricultural nutritional value research.

[0104] Table 3

[0105]

[0106]

[0107]

[0108]

[0109] Finally, it should be noted that the above examples are intended to illustrate the technical solutions of the present application, but not to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. Use of a porous covalent triazine framework material solid phase microextraction probe for in situ extraction and non-targeted qualitative analysis of in planta nutrients in vegetables at different growth stages, characterized in that, The porous covalent triazine-based material solid-phase microextraction probe comprises a stainless steel wire and a surface coating layer coated on the stainless steel wire, wherein the material of the surface coating layer is the porous covalent triazine-based material; the diameter of the stainless steel wire is 127 μm, and the length is 3-4 cm; the length of the surface coating layer is 0.8-1.2 cm, and the thickness is 25-40 μm. The preparation method of the porous covalent triazine-based material comprises the following steps: mixing cyanuric chloride and DMSO to obtain solution A; mixing melamine, alkali metal hydroxide and DMSO to obtain solution B; stirring solution B under the condition of-5-0 ℃ and inert gas environment, and adding solution A dropwise, then heating the reaction, centrifuging, washing and drying after the reaction to obtain the porous covalent triazine-based material; The preparation method of the triazine-based material solid-phase microextraction probe comprises the following steps: mixing silicone glue and o-xylene to obtain an adhesive solution; placing the pretreated stainless steel wire in the adhesive solution, then taking out and absorbing the adhesive solution on the surface of the stainless steel wire, then coating the porous covalent triazine-based material on the surface of the stainless steel wire, solidifying at 115-125 ℃ for 20-30 min after coating, repeating the coating-solidifying process, and finally aging at 240-260 ℃ for 50-70 min under inert gas environment after the last coating-solidifying to obtain the porous covalent triazine-based material solid-phase microextraction probe; The mass-volume ratio of the silicone glue and o-xylene is (0.4-0.6) g / mL. In the solution A, the molar-volume ratio of cyanuric chloride and DMSO is cyanuric chloride:DMSO=5 mmol:(48-52) mL. In the solution B, the molar-volume ratio of melamine, alkali metal hydroxide and DMSO is melamine:alkali metal hydroxide:DMSO=5 mmol:10 mmol:(48-52) mL.

2. Use of the porous covalent triazine framework material solid phase microextraction probe according to claim 1 for in situ extraction and non-targeted qualitative analysis of in planta nutrients in vegetables of different growth stages, characterized in that, The heating temperature is 150-165 ℃, and the heating time is 24-26 h.

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