Fluorine-rich covalent triazine skeleton functionalized silica gel stationary phase as well as preparation method and application thereof

Abstract

The invention belongs to the field of silica gel stationary phase materials for chromatographic analysis, and particularly relates to a fluorine-rich covalent triazine skeleton functionalized silica gel stationary phase as well as a preparation method and application thereof. The fluorine-rich covalent triazine skeleton functionalized silica gel stationary phase comprises a silica gel substrate, and a fluorine-rich covalent triazine skeleton is arranged on the surface of the silica gel substrate. A fluorine-rich covalent triazine skeleton is constructed on a silica gel matrix, multiple interactions such as hydrophobicity, pi-pi, C-F... pi, hydrogen bonds and halogen bonds are generated between the fluorine-rich covalent triazine skeleton and analytes, and high separation selectivity can be provided for analytes with similar structures.

Description

Technical Field

[0001] The present invention belongs to the field of silica gel stationary phase materials for chromatographic analysis, and particularly relates to a fluorine-rich covalent triazine framework functionalized silica gel stationary phase, a preparation method thereof, and an application thereof. Background Art

[0002] High performance liquid chromatography has been widely used in the fields of drug research and development, environmental monitoring, and food safety due to its excellent repeatability and precise quantitative analysis advantages. As the core of the liquid chromatography system, the chromatographic stationary phase has an extremely important impact on the separation performance. Researchers have successively developed a series of single-mode stationary phases to meet the needs of separation and analysis of various specific solutes. However, traditional single-mode stationary phases are quite difficult to separate analytes with similar chemical structures.

[0003] These analytes with similar structures include, but are not limited to, benzoylurea insecticides, halogenated benzotrifluorides, polychlorobenzenes, polybromobenzenes, alkylbenzenes, organophosphorus pesticides, sulfonamide compounds, etc. Taking benzoylurea insecticides as an example, such as flucythrinate, flucofuron, chlorfluazuron, hexaflumuron, lufenuron, etc., they are relatively close in structure and polarity, and traditional single-mode stationary phases cannot achieve efficient separation of such analytes.

[0004] Covalent Triazine Frameworks (CTFs) are a class of porous organic polymers containing triazine rings composed of covalently bonded light elements such as C, H, O, and N. Their frameworks contain a large amount of N elements, rich pore structures, and high specific surface areas, as well as excellent stability conferred by triazine rings. They are a class of novel chromatographic stationary phases with great potential and multiple binding sites. Such novel chromatographic stationary phases can contain groups such as covalent triazine groups and benzene rings, providing interaction types such as π-π stacking and hydrogen bonding. However, experiments have found that CTFs-benzene ring-based stationary phases still cannot efficiently separate analytes with highly similar structures. Summary of the Invention

[0005] The purpose of the present invention is to provide a fluorine-rich covalent triazine framework functionalized silica gel stationary phase to solve the problem that existing chromatographic stationary phases cannot achieve efficient separation of analytes with similar structures.

[0006] The second purpose of the present invention is to provide a preparation method of a fluorine-rich covalent triazine framework functionalized silica gel stationary phase to solve the above problems.

[0007] The third purpose of the present invention is to provide the application of a fluorine-rich covalent triazine framework functionalized silica gel stationary phase as a chromatographic stationary phase in chromatographic analysis to solve the problem of efficient and accurate separation and analysis of analytes with similar structures by the chromatographic system.

[0008] To achieve the first above-mentioned object, the technical solution adopted by the present invention is as follows:

[0009] A fluorine-rich covalent triazine framework functionalized silica stationary phase, comprising a silica matrix, on the surface of which a fluorine-rich covalent triazine framework is provided, and the structural unit of the fluorine-rich covalent triazine framework is shown in Formula I:

[0010]

[0011] In Formula I, "---" represents connection to the silica matrix or another structural unit.

[0012] The present invention belongs to a pioneering invention. By constructing a fluorine-rich covalent triazine framework on the silica matrix, multiple interactions such as hydrophobic, π-π, C-F…π, hydrogen bond, and halogen bond are generated with the analyte, which can provide high separation selectivity for analytes with similar structures.

[0013] Further preferably, the fluorine-rich covalent triazine framework is chemically bonded to the surface of the silica matrix, and the chemical bond is The N-terminal of this chemical bond is connected to the silica matrix, and the other end is connected to the structural unit of the fluorine-rich covalent triazine framework.

[0014] To achieve the second above-mentioned object, the technical solution adopted by the present invention is as follows:

[0015] A preparation method of a fluorine-rich covalent triazine framework functionalized silica stationary phase, comprising the following steps:

[0016] (1) Perform an aldehyde-amine condensation reaction on 2,3,5,6-tetrafluoroterephthalaldehyde and amino silica to obtain SiO2-CHO microspheres;

[0017] (2) The SiO2-CHO microspheres, 2,3,5,6-tetrafluoroterephthalaldehyde, ammonium iodide and a catalyst undergo a cyclotrimerization reaction to form the fluorine-rich covalent triazine framework on the silica surface.

[0018] In the preparation method of the fluorine-rich covalent triazine framework functionalized silica stationary phase of the present invention, after aldehyde group modification of amino silica, using ammonium iodide as the nitrogen source, 2,3,5,6-tetrafluoroterephthalaldehyde is directly cyclotrimerized on the silica surface to obtain the fluorine-rich covalent triazine framework functionalized silica stationary phase. This process has good stability, high reproducibility, and is easy to promote and apply.

[0019] Preferably, in step (1), the dosage ratio of amino silica to 2,3,5,6-tetrafluoroterephthalaldehyde is 3 g: 90-100 mg. Further preferably, the aldehyde-amine condensation reaction in step (1) is carried out in the presence of acetic acid, and the dosage ratio of amino silica to acetic acid is 3 g: 3-5 mL; the reaction temperature is 25-35 °C, and the reaction time is 24-36 h.

[0020] Preferably, in step (2), the dosage ratio of SiO2-CHO microspheres, 2,3,5,6-tetrafluoroterephthalaldehyde, and ammonium iodide is 3 g: 500-600 g: 700-800 mg.

[0021] More preferably, the catalyst is iron(III) acetate hydrate, and the dosage ratio of SiO2-CHO microspheres to iron(III) acetate hydrate is 3 g: 225-300 mg.

[0022] Preferably, the cyclotrimerization reaction includes reacting at 40-55 °C, 80-95 °C, 120-135 °C, and 160-175 °C for 24-36 h in sequence.

[0023] To achieve the above third object, the technical solution adopted by the present invention is:

[0024] Application of the above-mentioned fluorine-rich covalent triazine framework-functionalized silica stationary phase as a chromatographic stationary phase in chromatographic analysis.

[0025] When the above-mentioned fluorine-rich covalent triazine framework-functionalized silica stationary phase is applied to a high-performance liquid chromatography column, the column efficiency is as high as 59633 plates / m; at the same time, it has excellent solvent tolerance, good stability and reproducibility when applied to a mobile phase with a high content of organic solvents. For 10 consecutive injections, the relative standard deviation of the retention time is less than 0.27%. It can achieve the complete separation of organic halides (benzoylurea insecticides, halogenated benzotrifluorides, polychlorobenzenes, and polybromobenzenes, etc.) and non-organic halides (sulfonamides, organophosphorus pesticides, and alkylbenzenes, etc.), with a resolution as high as 6.18. Compared with the fluorine-free CTFs@SiO2 stationary phase, it shows ultra-high separation selectivity.

[0026] Preferably, the chromatographic analysis includes selective separation of structurally similar analytes by high-performance liquid chromatography, and the structurally similar analytes include benzoylurea insecticides, halogenated benzotrifluorides, polychlorobenzenes, polybromobenzenes, alkylbenzenes, organophosphorus pesticides, or sulfonamide compounds.

[0027] More preferably, the benzoylurea insecticides include flucofuron, flucycloxuron, chlorfluazuron, hexaflumuron, and lufenuron;

[0028] The halogenated benzotrifluorides include 2-fluorobenzotrifluoride, 2-chlorobenzotrifluoride, 2-bromobenzotrifluoride, and 2-iodobenzotrifluoride;

[0029] The polychlorobenzenes include chlorobenzene, o-dichlorobenzene, 1,2,3-trichlorobenzene, and 1,2,3,4-tetrachlorobenzene;

[0030] The polybromobenzenes include bromobenzene, m-dibromobenzene, 1,3,5-tribromobenzene, and 1,2,4,5-tetrabromobenzene;

[0031] The alkylbenzene includes toluene, ethylbenzene, n-propylbenzene, n-butylbenzene, and n-pentylbenzene;

[0032] The organophosphorus pesticides include diazinon, tetrachlorvinphos, profenofos, fenitrothion, fenthion, and phosalone;

[0033] The sulfonamide compounds include sulfanilamide, sulfaguanidine, sulfapyridine, sulfamethoxydiazine, and sulfadimethoxine. Description of the Drawings

[0034] Figure 1 It is the preparation flow chart of the F-CTFs@SiO2 chromatographic column of the present invention;

[0035] Figure 2 It is the scanning electron microscope image of the F-CTFs@SiO2 prepared in Example 1 of the present invention;

[0036] Figure 3 It is the infrared spectrum of the F-CTFs@SiO2 prepared in Example 1 of the present invention;

[0037] Figure 4 It is the solid-state nuclear magnetic resonance carbon spectrum of the F-CTFs@SiO2 and CTFs@SiO2 prepared in Example 1 of the present invention;

[0038] Figure 5 It is the nitrogen adsorption-desorption isotherm (a) and pore size distribution (b) of the F-CTFs@SiO2 prepared in Example 1 of the present invention.

[0039] Figure 6 It is the relationship diagram between the capacity factor k of benzoylurea insecticides and the acetonitrile content in the mobile phase on the F-CTFs@SiO2 chromatographic column in the experimental example of the present invention;

[0040] Figure 7 It is the chromatographic separation diagram (a) of benzoylurea insecticides on the F-CTFs@SiO2 chromatographic column and the chromatographic separation diagram (b) on the CTFs@SiO2 chromatographic column in the experimental example of the present invention;

[0041] Figure 8 It is the chromatographic separation diagram (a) of halogenated benzotrifluoride on the F-CTFs@SiO2 chromatographic column and the chromatographic separation diagram (b) on the CTFs@SiO2 chromatographic column in the experimental example of the present invention;

[0042] Figure 9 It is the chromatographic separation diagram (a) of polychlorobenzene on the F-CTFs@SiO2 chromatographic column and the chromatographic separation diagram (b) on the CTFs@SiO2 chromatographic column in the experimental example of the present invention;

[0043] Figure 10Chromatogram separation diagrams of polybromobenzenes on the F-CTFs@SiO2 chromatographic column (a) and on the CTFs@SiO2 chromatographic column (b) in the experimental examples of the present invention;

[0044] Figure 11 Chromatogram separation diagrams of alkylbenzenes on the F-CTFs@SiO2 chromatographic column (a) and on the CTFs@SiO2 chromatographic column (b) in the experimental examples of the present invention;

[0045] Figure 12 Chromatogram separation diagrams of organophosphorus pesticides on the F-CTFs@SiO2 chromatographic column (a) and on the CTFs@SiO2 chromatographic column (b);

[0046] Figure 13 Chromatogram separation diagrams of sulfonamides on the F-CTFs@SiO2 chromatographic column (a) and on the CTFs@SiO2 chromatographic column (b) in the experimental examples of the present invention;

[0047] Figure 14 Repeatability of sulfonamide compounds on the F-CTFs@SiO2 chromatographic column in the experimental examples of the present invention;

[0048] Figure 15 Chromatogram separation diagram of a benzoylurea insecticide standard solution (100 μg / mL), cucumber extract, and spiked cucumber extract (the spiked concentration of fluorobenzuron is 2 μg / mL, and the others are 4 μg / mL) on the F-CTFs@SiO2 chromatographic column. Detailed implementation mode

[0049] The present invention mainly introduces multiple fluorine atoms into the triazine-phenyl skeleton to form a fluorine-rich covalent triazine skeleton. Combining the combined effects of the triazine ring, benzene ring, fluorine atoms, etc., can well solve the problem of limited separation selectivity of structurally similar analytes.

[0050] The chromatographic stationary phase constructed according to the above strategy has rich multiple active sites and high chemical stability during high-performance liquid chromatography analysis, excellent solvent tolerance, and good stability and reproducibility.

[0051] The above-mentioned fluorine-rich covalent triazine skeleton-functionalized silica stationary phase can be used to prepare a chromatographic column according to the following method: Disperse the fluorine-rich covalent triazine skeleton-functionalized silica stationary phase microspheres into an organic solvent to form a suspension, then quickly pour the suspension into a homogenization tank, and then use the organic solvent as a displacement liquid to load it into a stainless steel column at a pressure of 40-80 MPa for 5-30 minutes, then reduce the pressure to 10-30 MPa, and continue to load the column for 3-20 minutes to obtain an F-CTFs@SiO2 microsphere chromatographic column.

[0052] When preparing the suspension, the dosage ratio of F-CTFs@SiO2 to the organic solvent is 2.3 g:50 mL, and the organic solvent can be selected from methanol or acetonitrile.

[0053] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. In the following embodiments, unless otherwise specified, the raw materials used are commercially available conventional raw materials. Among them, the amino silica gel has a particle size of 5 μm and a nitrogen content of 1.45%, and is purchased from Suzhou NanoMicro Technologies Co., Ltd. Unless otherwise specified, the ratio of the mobile phase is a volume ratio.

[0054] I. Specific embodiments of the fluorine-rich covalent triazine framework functionalized silica gel stationary phase and its preparation method of the present invention

[0055] Example 1

[0056] The preparation method of the fluorine-rich covalent triazine framework functionalized silica gel stationary phase in this example is shown in the overall reaction schematic diagram as Figure 1 shown, and includes the following steps:

[0057] (1) Add 3.0 g of amino silica gel, 92.5 mg of 2,3,5,6-tetrafluoroterephthalaldehyde, and 3.6 mL of acetic acid (12 mol / L) to 75 mL of acetonitrile in sequence, and ultrasonically obtain a uniformly dispersed solution. Place this solution at 25 °C and stir it evenly for 24 h; after the reaction is completed, cool it to room temperature, wash it three times with absolute ethanol, and vacuum dry it for 12 h to obtain SiO2-CHO.

[0058] (2) Ultrasonically disperse 3.0 g of SiO2-CHO, 515.0 mg of 2,3,5,6-tetrafluoroterephthalaldehyde, 750.0 mg of ammonium iodide, and 225.0 mg of iron(III) acetate hydrate (purchased from Shanghai Macklin Biochemical Co., Ltd., cas: 10450-55-2) in 80 mL of anhydrous o-dichlorobenzene, and stir it at 40 °C, 80 °C, 120 °C, and 160 °C for 24 h respectively; after the reaction is completed, cool it to room temperature, and wash it three times with N,N-dimethylformamide, 0.1 mol / L dilute hydrochloric acid solution, deionized water, and absolute ethanol in sequence, and vacuum dry it for 12 h to obtain F-CTFs@SiO2.

[0059] Preparation of the F-CTFs@SiO2 chromatographic column: Weigh 2.3 g of the F-CTFs@SiO2 stationary phase, add it to 60 mL of methanol, and ultrasonically disperse it to form a suspension. Then quickly pour the suspension into a homogenization tank, and use methanol as the displacement liquid to pack the column at a pressure of 60 MPa for 15 min. Then reduce the pressure to 20 MPa and continue to pack the column for 10 min to obtain an F-CTFs@SiO2 chromatographic column (150 mm × 4.6 mm). In this step, replacing methanol with acetonitrile can also successfully achieve the column packing of the chromatographic column and the use of the chromatographic column.

[0060] II. Comparative Examples

[0061] Comparative Example 1

[0062] This comparative example illustrates the preparation process of fluorine-free CTFs@SiO2, which specifically includes the following steps:

[0063] (1) Add 3.0 g of amino silica gel, 60.4 mg of terephthalaldehyde, 3.6 mL of acetic acid (12 mol / L) into 75 mL of acetonitrile, and ultrasonically obtain a uniformly dispersed solution. Place this solution at 25 °C and stir it evenly for 24 h; after the reaction ends, cool it to room temperature, wash it three times with absolute ethanol, and vacuum dry it for 12 h to obtain SiO2@CHO.

[0064] (2) Ultrasonically disperse 3.0 g of SiO2@CHO, 335.3 mg of terephthalaldehyde, 750.0 mg of ammonium iodide, and 225.0 mg of iron(III) acetate hydrate in 80 mL of anhydrous o-dichlorobenzene, and stir it for 24 h at 40 °C, 80 °C, 120 °C, and 160 °C respectively; after the reaction ends, cool it to room temperature, wash it three times with N,N-dimethylformamide, 0.1 mol / L dilute hydrochloric acid solution, deionized water, and absolute ethanol respectively, and vacuum dry it for 12 h to obtain fluorine-free CTFs@SiO2.

[0065] Weigh 2.3 g of CTFs@SiO2 stationary phase and add it to 50 mL of methanol to ultrasonically disperse to form a suspension. Then quickly pour the suspension into a homogenization tank, and use methanol as the displacement liquid to pack the column at a pressure of 60 MPa for 20 min, and then reduce the pressure to 20 MPa and continue to pack the column for 5 min to obtain a CTFs@SiO2 chromatographic column (150 mm × 4.6 mm).

[0066] III. Application of Fluorine-Rich Covalent Triazine Framework Functionalized Silica Stationary Phase as a Chromatographic Stationary Phase in Chromatographic Analysis

[0067] Experimental Example 1

[0068] Use scanning electron microscopy to characterize the morphology and elemental distribution of F-CTFs@SiO2 prepared in Example 1, and the results are as Figure 2 shown.

[0069] As can be seen from Figure 2 a, the surface of F-CTFs@SiO2 is rough, and a large number of F-CTFs particles grow in-situ on the surface of SiO2-CHO, and its particle size is about 5.3 μm. X-ray energy spectrum analysis ( Figure 2 b-2d) shows that in addition to C and N elements, F elements are evenly distributed on the surface of F-CTFs@SiO2 microspheres, confirming the successful synthesis of the F-CTFs@SiO2 stationary phase material.

[0070] The F-CTFs@SiO2 microspheres prepared in Example 1 were analyzed by infrared spectroscopy. As Figure 3 shown, the absorption peaks at 1093, 817, and 470 cm -1 are respectively attributed to the asymmetric stretching vibration of Si-O-Si in SiO2-NH2, the symmetric stretching vibration of SiO-H, and the bending vibration of Si-O. The absorption peaks at 1357 and 1533 cm -1 are attributed to the vibration of the triazine ring of F-CTFs, and the absorption peak at 981 cm -1 is attributed to the stretching vibration of C-F on F-CTFs. The characteristic peaks of the triazine ring of F-CTFs at 1357 and 1533 cm -1 appear in the FTIR curve of F-CTFs@SiO2, and the C-F characteristic peak at 981 cm -1 overlaps with the asymmetric stretching vibration peak of Si-O-Si.

[0071] The structures of the F-CTFs@SiO2 prepared in Example 1 and the CTFs@SiO2 microspheres prepared in Comparative Example 1 were characterized by solid-state nuclear magnetic resonance carbon spectroscopy. As Figure 4 shown, the signal of CTFs@SiO2 at 136 ppm corresponds to the chemical shift of the aromatic carbon connected to the triazine ring, and the signal at 128 ppm is attributed to the chemical shift of the aromatic carbon on the benzene ring; in the solid-state nuclear magnetic resonance carbon spectrum of F-CTFs@SiO2, the carbon signal of the fluorinated benzene ring is located at 145 ppm. In addition, due to the introduction of fluorine atoms, the aromatic carbon signal connected to the triazine ring is shifted to 118 ppm, indicating that F-CTFs@SiO2 was successfully prepared.

[0072] Experimental Example 2

[0073] The pore size distribution of the F-CTFs@SiO2 microspheres prepared in Example 1 was characterized by nitrogen adsorption-desorption, and the results are as Figure 5 shown.

[0074] As can be seen from Figure 5 a, the nitrogen adsorption amount of F-CTFs@SiO2 increases sharply in the low-pressure region, and there is an obvious hysteresis loop in the medium-pressure region, indicating that the prepared F-CTFs@SiO2 microspheres have both micropores and mesopores and have a significant hierarchical multi-porous structure; from the pore size distribution diagram in Figure 5 b, the micropore sizes are approximately 0.68 nm and 1.06 nm, and the mesopore size is approximately 21.63 nm.

[0075] Experimental Example 3 Separation Performance of Benzoylurea Insecticides

[0076] Using the F-CTFs@SiO2 chromatographic column prepared in Example 1 as a high-performance liquid chromatography column, the separation performance of this chromatographic column for benzoylurea insecticides was tested.

[0077] Figure 6 Among them, the test solution was a methanol-acetonitrile-dimethyl sulfoxide mixed solution (volume ratio of methanol, acetonitrile, and dimethyl sulfoxide was 9:0.9:0.1) of triflumuron (0.029 mg / mL), flucycloxuron (0.058 mg / mL), chlorfluazuron (0.035 mg / mL), hexaflumuron (0.578 mg / mL), and flufenoxuron (0.012 mg / mL); the chromatographic separation conditions were: the mobile phase was a mixed solution of acetonitrile / water with different concentrations, the flow rate was 1.2 mL / min, and the detection wavelength was 254 nm. The capacity factor k of the 5 benzoylurea insecticides decreased with the increase of the acetonitrile content in the mobile phase, indicating that this stationary phase conformed to the reversed-phase chromatography mode.

[0078] Figure 7 Among them, under the further condition of fixing the mobile phase as acetonitrile / water = 58 / 42, Figure 7 a, Figure 7 b respectively show the separation performance of the F-CTFs@SiO2 chromatographic column of Example 1 and the CTFs@SiO2 chromatographic column of Comparative Example 1. Figure 7 In a, chromatographic peaks 1-5 were triflumuron, flucycloxuron, chlorfluazuron, hexaflumuron, and flufenoxuron respectively, and the 5 benzoylurea insecticides were well separated on the F-CTFs@SiO2 chromatographic column. Under the same chromatographic conditions, the 5 benzoylurea insecticides could not achieve baseline separation on the CTFs@SiO2 chromatographic column prepared in Comparative Example 1 ( Figure 7 b), which indicated that the abundant fluorine sites played an important role in the separation of the 5 benzoylurea insecticides on the F-CTFs@SiO2 chromatographic column.

[0079] Separation performance of halogenated benzotrifluorides in Experimental Example 4

[0080] Using the F-CTFs@SiO2 chromatographic column prepared in Example 1 as a high-performance liquid chromatography column, the separation performance of this chromatographic column for halogenated benzotrifluorides was tested. The test solution was a methanol mixed solution of 2-fluorobenzotrifluoride (0.25 mg / mL), 2-chlorobenzotrifluoride (0.25 mg / mL), 2-bromobenzotrifluoride (0.25 mg / mL), and 2-iodobenzotrifluoride (0.25 mg / mL). The chromatographic separation conditions were: mobile phase: methanol / water = 70 / 30, flow rate: 1.0 mL / min, detection wavelength: 210 nm. The separation results of the chromatographic columns of Example 1 and Comparative Example 1 were as Figure 8 shown.

[0081] As Figure 8As shown in a, chromatographic peaks 1 - 4 are 2-fluorobenzotrifluoride, 2-chlorobenzotrifluoride, 2-bromobenzotrifluoride, and 2-iodobenzotrifluoride respectively. The four kinds of halogenated benzotrifluorides are successfully separated on the prepared chromatographic column. Due to the strong electronegativity of fluorine atoms, they usually act as electron acceptors in halogen bonds, and the electron-donating ability of halogen atoms decreases in the order of I, Br, Cl, F. Therefore, the order of halogen bond strength is F-I > F-Br > F-Cl > F-F. From Figure 8 a, it can be seen that the retention order of halogenated benzotrifluorides on the F-CTFs@SiO2 chromatographic column is fluorobenzotrifluoride < chlorobenzotrifluoride < bromobenzotrifluoride < iodobenzotrifluoride, which is in line with the order of the strength of halogen bonds between halogenated benzotrifluorides and the F-CTFs@SiO2 stationary phase, indicating the importance of halogen bonds in the separation of halogenated benzotrifluorides. Under the same chromatographic conditions, the four kinds of halogenated benzotrifluorides are not completely separated on the CTFs@SiO2 stationary phase prepared in Comparative Example 1 ( Figure 8 b), confirming the important contribution of fluorine functional sites to the separation of organic halides.

[0082] Separation performance of polychlorobenzenes in Experimental Example 5

[0083] Using the F-CTFs@SiO2 chromatographic column prepared in Example 1 as a high-performance liquid chromatography column, the separation performance of this chromatographic column for polychlorobenzenes was tested. The test solution was a methanol mixed solution of chlorobenzene (0.25 mg / mL), o-dichlorobenzene (0.25 mg / mL), 1,2,3-trichlorobenzene (0.25 mg / mL), and 1,2,3,4-tetrachlorobenzene (0.25 mg / mL). The chromatographic separation conditions were: mobile phase: methanol / water = 85 / 15, flow rate: 1.0 mL / min, detection wavelength: 214 nm. The separation results of the chromatographic columns in Example 1 and Comparative Example 1 are as Figure 9 shown.

[0084] As Figure 9 shown in a, chromatographic peaks 1 - 4 are chlorobenzene, o-dichlorobenzene, 1,2,3-trichlorobenzene, and 1,2,3,4-tetrachlorobenzene respectively. The four kinds of polychlorobenzenes are efficiently separated on the F-CTFs@SiO2 chromatographic column within 5 minutes, but under the same chromatographic conditions, they cannot be effectively separated on the CTFs@SiO2 chromatographic column prepared in Comparative Example 1 ( Figure 9 b). The above results further indicate that the fluorine-rich sites in F-CTFs@SiO2 contribute to improving the separation selectivity of organic halides.

[0085] Separation performance of polybromobenzenes in Experimental Example 6

[0086] Using the F-CTFs@SiO2 chromatographic column prepared in Example 1 as a high-performance liquid chromatography column, the separation performance of this column for polybromobenzenes was tested. The test solution was a methanol-dimethyl sulfoxide mixed solution (volume ratio of methanol to dimethyl sulfoxide was 9:1) of bromobenzene (0.25 mg / mL), m-dibromobenzene (0.25 mg / mL), 1,3,5-tribromobenzene (0.25 mg / mL), and 1,2,4,5-tetrabromobenzene (0.25 mg / mL). The chromatographic separation conditions were: mobile phase: methanol / water = 85 / 15, flow rate: 1.0 mL / min, detection wavelength: 214 nm. The separation results of the chromatographic columns of Example 1 and Comparative Example 1 are as Figure 10 shown.

[0087] As Figure 10 shown in a, chromatographic peaks 1-4 were bromobenzene, m-dibromobenzene, 1,3,5-tribromobenzene, and 1,2,4,5-tetrabromobenzene, respectively. The four polybromobenzenes were efficiently separated on the F-CTFs@SiO2 chromatographic column. Under the same chromatographic conditions, bromobenzene and m-dibromobenzene were co-eluted on the CTFs@SiO2 chromatographic column prepared in Comparative Example 1 ( Figure 10 b), further confirming that the halogen bond formed between F-CTFs@SiO2 and organic halides played a key role in the separation of the four polybromobenzenes.

[0088] Separation performance of alkylbenzenes in Experimental Example 7

[0089] Using the F-CTFs@SiO2 chromatographic column prepared in Example 1 as a high-performance liquid chromatography column, the separation performance of this column for alkylbenzenes was tested. The test solution was a methanol mixed solution of toluene (0.25 mg / mL), ethylbenzene (0.25 mg / mL), n-propylbenzene (0.25 mg / mL), n-butylbenzene (0.25 mg / mL), and n-pentylbenzene (0.25 mg / mL). The chromatographic separation conditions were: mobile phase: acetonitrile / water = 55 / 45, flow rate: 1.0 mL / min, detection wavelength: 254 nm. The separation results of the chromatographic columns of Example 1 and Comparative Example 1 are as Figure 11 shown.

[0090] As Figure 11 shown in a, chromatographic peaks 1-5 were toluene, ethylbenzene, n-propylbenzene, n-butylbenzene, and n-pentylbenzene, respectively. The F-CTFs@SiO2 chromatographic column achieved complete separation of the five alkylbenzenes within 5.5 min. Under the same chromatographic conditions, n-propylbenzene, n-butylbenzene, and n-pentylbenzene were co-eluted on the CTFs@SiO2 chromatographic column prepared in Example 1 ( Figure 11 b). The high selectivity of the F-CTFs@SiO2 chromatographic column for hydrophobic alkylbenzenes may be mainly attributed to the existence of multiple interactions such as hydrophobic, π-π, and C-F…π between F-CTFs@SiO2 and alkylbenzenes.

[0091] Separation Performance for Organophosphorus Pesticides in Experimental Example 8

[0092] Using the F-CTFs@SiO2 chromatographic column prepared in Example 1 as a high-performance liquid chromatography column, the separation performance of this chromatographic column for organophosphorus pesticides was tested. The test solution was a methanol-acetonitrile mixed solution (volume ratio of methanol to acetonitrile was 1:1) of diazinon (0.2 mg / mL), tetrachlorvinphos (0.2 mg / mL), profenofos (0.1 mg / mL), fenitrothion (0.2 mg / mL), fenthion (0.1 mg / mL), and phosalone (0.2 mg / mL). The chromatographic separation conditions were as follows: mobile phase: methanol / water = 85 / 15, flow rate: 1.0 mL / min, detection wavelength: 225 nm. The separation results of the chromatographic columns in Example 1 and Comparative Example 1 are as Figure 12 shown.

[0093] As Figure 12 shown in a, chromatographic peaks 1-6 were diazinon, tetrachlorvinphos, profenofos, fenitrothion, fenthion, and phosalone respectively, and the F-CTFs@SiO2 chromatographic column showed good separation selectivity for the 6 organophosphorus pesticides. Under the same chromatographic conditions, the separation effect of the 6 organophosphorus pesticides on the CTFs@SiO2 chromatographic column prepared in Example 1 was poor ( Figure 12 b).

[0094] Separation Performance for Sulfonamides in Experimental Example 9

[0095] Using the F-CTFs@SiO2 chromatographic column prepared in Example 1 as a high-performance liquid chromatography column, the separation performance of this chromatographic column for sulfonamides was tested. The test solution was a methanol mixed solution of sulfanilamide (0.107 mg / mL), sulfaguanidine (0.134 mg / mL), sulfapyridine (0.402 mg / mL), sulfamethoxydiazine (0.179 mg / mL), and sulfamethazine (0.179 mg / mL). The chromatographic separation conditions were as follows: mobile phase: methanol / water = 87.5 / 12.5, flow rate: 1.0 mL / min, detection wavelength: 270 nm. The separation results of the chromatographic columns in Example 1 and Comparative Example 1 are as Figure 13 shown.

[0096] As Figure 13 shown in a, chromatographic peaks 1-5 were sulfanilamide, sulfaguanidine, sulfapyridine, sulfamethoxydiazine, and sulfamethazine respectively, and the F-CTFs@SiO2 chromatographic column achieved baseline separation for the 5 sulfonamides. Under the same chromatographic conditions, sulfaguanidine, sulfapyridine, sulfamethoxydiazine, and sulfamethazine were co-eluted on the CTFs@SiO2 chromatographic column prepared in Comparative Example 1 ( Figure 13b). The high selectivity of the F-CTFs@SiO2 chromatographic column for polar sulfonamides may be mainly attributed to the hydrogen bond interaction between F-CTFs@SiO2 and sulfonamides.

[0097] As Figure 14 shown, after 10 consecutive injections, the relative standard deviations of the retention times of the 5 sulfonamides were all not more than 0.27%, indicating that the F-CTFs@SiO2 stationary phase has good reproducibility and stability.

[0098] Experimental Example 10 Analysis of actual samples

[0099] Based on the excellent stability of the F-CTFs@SiO2 chromatographic column and its good separation performance for analytes with similar polarity or structure, cucumber was selected as the test sample to investigate the application potential of this chromatographic column in the separation and analysis of actual samples.

[0100] The chromatograms of the benzoylurea insecticide standard solution (100 μg / mL), cucumber extract, and spiked cucumber extract (the spiked concentration of flucycloxuron was 2 μg / mL, and the others were 4 μg / mL) on the F-CTFs@SiO2 chromatographic column are shown in Figure 15 (Chromatographic peaks 1-5 are flucycloxuron, flucumuron, chlorfluazuron, hexaflumuron, and lufenuron respectively).

[0101] Since no residues of benzoylurea insecticides were detected in the cucumber samples, the benzoylurea insecticide standard solution was added to the cucumber extract to investigate the separation of benzoylurea insecticides from the matrix by this chromatographic column. Figure 15 It is shown that the F-CTFs@SiO2 chromatographic column achieved good separation of the 5 benzoylurea insecticides from the cucumber matrix, verifying the application potential of the F-CTFs@SiO2 chromatographic column in practice.

[0102] Combined with HPLC-UV detection technology, the F-CTFs@SiO2 chromatographic column was used to verify the methodology for the determination of benzoylurea insecticides in cucumber samples, and the results are shown in Table 1.

[0103] Table 1 Analysis results of cucumber samples

[0104]

[0105] As shown in Table 1, the five benzoylurea insecticides all had good linear relationships in the concentration range of 0.15 - 52 μg / mL, with correlation coefficients greater than 0.9938. The detection limits and quantification limits were between 0.05 - 0.1 μg / mL and 0.15 - 0.3 μg / mL, respectively. Benzoylurea insecticides at high, medium, and low concentration levels were added to cucumber samples to verify the accuracy of the method. The spiked recoveries of the five benzoylurea insecticides were 96.75% - 108.9%, and the relative standard deviations were 0.12% - 1.95%, indicating that this method can be used for the determination of benzoylurea insecticides in cucumbers.

[0106] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fluorine-rich covalent triazine framework functionalized silica stationary phase, characterized in that, It includes a silica matrix, and a fluorine-rich covalent triazine framework is disposed on the surface of the silica matrix. The structural unit of the fluorine-rich covalent triazine framework is shown in Formula I:

2. The fluorine-rich covalent triazine framework-functionalized silica stationary phase according to claim 1, wherein The fluorine-rich covalent triazine framework is connected to the surface of the silica matrix through chemical bonds, and the chemical bonds are 3. A preparation method of the fluorine-rich covalent triazine framework-functionalized silica stationary phase as described in claim 1 or 2, characterized in that, It includes the following steps: (1) 2,3,5,6-Tetrafluoroterephthalaldehyde and amino silica undergo an aldehyde-amine condensation reaction to obtain SiO2-CHO microspheres; (2) The SiO2-CHO microspheres, 2,3,5,6-tetrafluoroterephthalaldehyde, ammonium iodide and a catalyst undergo a cyclotrimerization reaction to form the fluorine-rich covalent triazine framework on the silica surface.

4. The preparation method of the fluorine-rich covalent triazine framework functionalized silica stationary phase according to claim 3, wherein, In step (1), the dosage ratio of amino silica to 2,3,5,6-tetrafluoroterephthalaldehyde is 3 g: 90 - 100 mg.

5. The preparation method of the fluorine-rich covalent triazine framework functionalized silica stationary phase according to claim 4, characterized in that, The aldehyde-amine condensation reaction in step (1) is carried out in the presence of acetic acid. The dosage ratio of amino silica to acetic acid is 3 g: 3 - 5 mL; the reaction temperature is 25 - 35 °C, and the reaction time is 24 - 36 h.

6. The preparation method of the fluorine-rich covalent triazine framework functionalized silica stationary phase according to claim 3, characterized in that, In step (2), the dosage ratio of SiO2-CHO microspheres, 2,3,5,6-tetrafluoroterephthalaldehyde, and ammonium iodide is 3 g: 500 - 600 g: 700 - 800 mg.

7. The preparation method of the fluorine-rich covalent triazine framework-functionalized silica stationary phase according to claim 6, characterized in that, The catalyst is iron(III) acetate hydrate, and the dosage ratio of SiO2-CHO microspheres to iron(III) acetate hydrate is 3 g: 225 - 300 mg.

8. The preparation method of the fluorine-rich covalent triazine framework-functionalized silica stationary phase according to claim 3, characterized in that, The cyclotrimerization reaction includes reacting at 40 - 55 °C, 80 - 95 °C, 120 - 135 °C, and 160 - 175 °C for 24 - 36 h in sequence.

9. Application of the fluorine-rich covalent triazine framework-functionalized silica stationary phase as claimed in claim 1 or 2 as a chromatographic stationary phase in chromatographic analysis.

10. The application according to claim 9, characterized in that, The chromatographic analysis includes selectively separating structurally similar analytes by high performance liquid chromatography. The structurally similar analytes include benzoylurea insecticides, halogenated benzotrifluorides, polychlorobenzenes, polybromobenzenes, alkylbenzenes, organophosphorus pesticides or sulfonamide compounds.

11. The application according to claim 10, wherein The benzoylurea insecticides include flucythrinate, flucofuron, chlorfluazuron, hexaflumuron, lufenuron; The halogenated benzotrifluorides include 2-fluorobenzotrifluoride, 2-chlorobenzotrifluoride, 2-bromobenzotrifluoride, 2-iodobenzotrifluoride; The polychlorobenzenes include chlorobenzene, o-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,3,4-tetrachlorobenzene; The polybromobenzenes include bromobenzene, m-dibromobenzene, 1,3,5-tribromobenzene, 1,2,4,5-tetrabromobenzene; The alkylbenzenes include toluene, ethylbenzene, n-propylbenzene, n-butylbenzene, n-pentylbenzene; The organophosphorus pesticides include diazinon, tetrachlorvinphos, profenofos, fenitrothion, fenthion, phosalone; The sulfonamide compounds include sulfanilamide, sulfaguanidine, sulfapyridine, sulfamethoxydiazine, sulfadimethoxine.

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