阅读说明：本技术 色谱材料及制备方法、微型色谱柱及涂覆方法和微型气相色谱仪 (Chromatographic material and preparation method thereof, micro chromatographic column and coating method thereof and micro gas chromatograph ) 是由 石静文 段学欣 屈贺幂 于 2021-08-26 设计创作，主要内容包括：本发明提出一种色谱材料及其制备方法、微型色谱柱及其涂覆方法和微型气相色谱仪。该色谱材料制备方法,包括：在磁性微粒的表面增加一层金属有机框架材料的固定相以实现表面修饰,然后清洗并且分离取出磁性微粒；将上述步骤重复执行N次,N为正整数。根据本发明的技术方案,第一方面,色谱材料表面包覆了若干层金属有机框架材料作为固定相,因此具有更深的内部结构,更大的比表面积,能够明显提色谱分离性能；第二方面,由于色谱材料的载体采用磁性颗粒,因此可以利用外部磁力来协助分离操作以及固定在色谱柱中,具有简便易行的优点。(The invention provides a chromatographic material and a preparation method thereof, a micro chromatographic column and a coating method thereof and a micro gas chromatograph. The preparation method of the chromatographic material comprises the following steps: adding a layer of stationary phase of metal organic framework material on the surface of the magnetic particles to realize surface modification, and then cleaning and separating to take out the magnetic particles; and repeating the steps for N times, wherein N is a positive integer. According to the technical scheme of the invention, on the first hand, the surface of the chromatographic material is coated with a plurality of layers of metal organic framework materials as the stationary phase, so that the chromatographic material has a deeper internal structure and a larger specific surface area, and the chromatographic separation performance can be obviously improved; in the second aspect, since the magnetic particles are used as the carrier of the chromatographic material, the external magnetic force can be used to assist the separation operation and fix the chromatographic material in the chromatographic column, which is simple and easy to implement.)

1. A method for preparing a chromatographic material, which is characterized by comprising the following steps:

adding a layer of stationary phase of metal organic framework material on the surface of the magnetic particles to realize surface modification, and then cleaning and separating to take out the magnetic particles;

and repeating the steps for N times, wherein N is a positive integer.

2. The method according to claim 1, wherein the magnetic particles are magnetic silica particles or ferroferric oxide particles.

3. The method of claim 1, wherein the magnetic particles have an average particle size of 1 to 10 microns.

4. The method of claim 1, wherein the magnetic particles are spherical, rod-shaped, or dendritic.

5. The method of claim 1, wherein 1 ≦ N ≦ 60.

6. The method according to claim 1, wherein the metal organic framework material is HKUST-1, and the step of adding a layer of stationary phase of metal organic framework material on the surface of the magnetic particles to achieve surface modification, and then washing and separating the magnetic particles comprises:

soaking the magnetic particles in an ethanol solution of copper acetate for a first time period, and then separating and taking out the magnetic particles;

soaking the magnetic particles in an ethanol solution of a trimesic acid solution for a second time, and then separating and taking out the magnetic particles;

and soaking the magnetic particles in an ethanol solution for a third time period, and then separating and taking out.

7. The method according to claim 5, wherein the concentration of the copper acetate solution is 0.5 to 1.5mMol and the concentration of the trimesic acid solution is 0.1 to 0.3 mMol.

8. The method of claim 5, wherein the first time period is 1 to 5 minutes, the second time period is 3 to 7 minutes, and the third time period is 1 to 5 minutes.

9. The method of claim 1, wherein the metal organic framework material is ZIF-8, and the step of adding a layer of stationary phase of metal organic framework material on the surface of the magnetic particles to achieve surface modification, and then washing and separating the magnetic particles comprises:

soaking the magnetic particles in an isometric mixed solution of zinc nitrate hexahydrate methanol solution and 2-methylimidazole methanol solution, keeping the magnetic particles for a fourth time, and then separating and taking out the magnetic particles;

and soaking the magnetic particles in a methanol solution for a fifth time period and then separating and taking out.

10. The method as claimed in claim 8, wherein the concentration of the zinc nitrate hexahydrate in methanol is 20 to 30 mmols and the concentration of the 2-methylimidazole in methanol is 40 to 50 mmols.

11. The method of claim 5, wherein the fourth time period is 30 to 60 minutes and the fifth time period is 5 to 10 minutes.

12. The method of claim 1, wherein the separating and removing is performed by: and adsorbing the magnetic particles on the inner wall of the container by using external magnetic force to remove other liquid.

13. A chromatographic material prepared by the method of any one of claims 1 to 12.

14. A micro-column, wherein the micro-column is coated with the chromatographic material of claim 13.

15. A method of coating a micro-chromatography column, comprising:

disposing the chromatographic material of claim 13 into a suspension;

injecting the suspension into a micro-chromatography column;

the chromatographic material is immobilized within the mini-column using an external magnetic force.

16. The method of claim 15, wherein after the step of immobilizing the chromatographic material within the micro-chromatography column using the external magnetic force, further comprising:

injecting air into the inlet end of the micro-chromatographic column so as to discharge the liquid material of the suspension;

helium is passed through the mini-column and held for a period of time to allow complete evaporation of the liquid.

17. The method of claim 15, wherein the step of immobilizing the chromatographic material within the mini-column using an external magnetic force comprises:

placing a permanent magnet or an electromagnet under the micro-chromatographic column to allow the chromatographic material to settle and fix within the micro-chromatographic column.

18. The method of claim 15, wherein in the step of configuring the chromatographic material as a suspension, the volume of the chromatographic material is no more than one fifth of the volume of the minicromatography column.

19. A micro-scale gas chromatograph comprising the micro-scale chromatographic column of claim 14; and contains permanent or electromagnets for fixing the chromatography material in the micro chromatography column.

Technical Field

The invention relates to a chromatographic material and a preparation method thereof, a micro chromatographic column and a coating method thereof and a micro gas chromatograph.

Background

With the development of micro-electro-mechanical systems (MEMS) technology, miniaturization of instruments has become an inevitable trend. Gas chromatographs are increasingly being studied for miniaturization as an important instrument for separating and detecting a mixed gas. Micro gas chromatography columns (μ GC) are an important component of micro gas chromatographs, and studies on stationary phases used therein are also increasing.

The most commonly used micro-scale gas chromatography stationary phase material at present is a polymer material, such as polydimethylsiloxane, polyethylene glycol, polytrifluoropropylmethylsiloxane, polycyanoxydimethylsiloxane and the like, which is generally modified into the interior of a micro-scale chromatographic column by a static or dynamic coating method. The polymer stationary phase material is adhered to the bottom and the side wall of the micro chromatographic column flow channel in the form of surface film. Therefore, when gas separation is performed, the contact area of gas molecules with the stationary phase material is small, resulting in poor separation ability of the micro-column for volatile organic compounds.

In addition, researchers in various countries have developed some novel stationary phase materials with larger specific surface area, such as carbon nanotubes, gold nanoparticles, ionic liquids, and the like. Compared with the traditional stationary phase material, the novel stationary phase material has larger specific surface area, thereby having better separation effect. The above-mentioned stationary phase material, although having a larger specific surface area, is still spread on the inside of the micro-chromatograph, and the separation ability is improved to a limited extent. Therefore, when gas separation is performed, the contact area of the gas molecules and the stationary phase is only the pore area of the material inside the chromatographic column, and therefore the separation effect of the method still needs to be improved.

There is therefore a need for a chromatographic material and method of preparation that overcomes the deficiencies of the prior art.

Disclosure of Invention

In view of the above, the present invention provides a chromatography material and a preparation method thereof, a micro chromatography column and a coating method thereof, and a micro gas chromatograph, so as to solve the problems in the prior art. The invention provides the following technical scheme:

the invention provides a preparation method of a chromatographic material, which comprises the following steps: adding a layer of stationary phase of metal organic framework material on the surface of the magnetic particles to realize surface modification, and then cleaning and separating to take out the magnetic particles; and repeating the steps for N times, wherein N is a positive integer.

Optionally, the magnetic particles are magnetic silica particles or ferroferric oxide particles.

Optionally, the magnetic particles have an average particle size of 1 to 10 microns.

Optionally, the magnetic particles are spherical, rod-shaped, or dendritic.

Alternatively, where 1 ≦ N ≦ 60.

Optionally, the metal-organic framework material is HKUST-1, and the step of adding a layer of stationary phase of metal-organic framework material on the surface of the magnetic particle to achieve surface modification, and then washing and separating the magnetic particle comprises: soaking the magnetic particles in an ethanol solution of copper acetate for a first time period, and then separating and taking out the magnetic particles; soaking the magnetic particles in an ethanol solution of a trimesic acid solution for a second time, and then separating and taking out the magnetic particles; and soaking the magnetic particles in an ethanol solution for a third time period, and then separating and taking out.

Alternatively, the concentration of the copper acetate solution is 0.5 to 1.5mMol and the concentration of the trimesic acid solution is 0.1 to 0.3 mMol.

Optionally, the first time period is 1 to 5 minutes, the second time period is 3 to 7 minutes, and the third time period is 1 to 5 minutes.

Optionally, the metal organic framework material is ZIF-8, and the step of adding a layer of stationary phase of metal organic framework material on the surface of the magnetic particle to achieve surface modification, and then washing and separating to remove the magnetic particle includes: soaking the magnetic particles in an isometric mixed solution of zinc nitrate hexahydrate methanol solution and 2-methylimidazole methanol solution, keeping the magnetic particles for a fourth time, and then separating and taking out the magnetic particles; and soaking the magnetic particles in a methanol solution for a fifth time period and then separating and taking out.

Optionally, the concentration of the zinc nitrate hexahydrate methanol solution is 20 to 30mMol, and the concentration of the 2-methylimidazole methanol solution is 40 to 50 mMol.

Optionally, the fourth time period is 30 to 60 minutes and the fifth time period is 5 to 10 minutes.

Optionally, the separating and removing process includes: and adsorbing the magnetic particles on the inner wall of the container by using external magnetic force to remove other liquid.

The second aspect of the invention provides a chromatographic material prepared by the preparation method of the chromatographic material disclosed by the invention.

In a third aspect, the present invention provides a micro-chromatography column having a coating of the chromatography material disclosed herein.

The fourth aspect of the present invention provides a coating method for a micro-chromatography column, comprising: preparing a chromatographic material disclosed by the invention into a suspension; injecting the suspension into a micro-chromatography column; the chromatographic material is immobilized within the mini-column using an external magnetic force.

Optionally, after the step of fixing the chromatographic material in the micro-chromatographic column by using the external magnetic force, the method further comprises: injecting air into the inlet end of the micro-chromatographic column so as to discharge the liquid material of the suspension; helium is passed through the mini-column and held for a period of time to allow complete evaporation of the liquid.

Optionally, the step of immobilizing the chromatographic material within the mini-column using an external magnetic force comprises: placing a permanent magnet or an electromagnet under the micro-chromatographic column to allow the chromatographic material to settle and fix within the micro-chromatographic column.

Optionally, in the step of configuring the chromatographic material as a suspension, the volume of the chromatographic material is no more than one fifth of the volume of the micro-chromatography column.

The fifth aspect of the invention provides a micro gas chromatograph, which comprises the micro chromatographic column disclosed by the invention; and contains permanent or electromagnets for fixing the chromatography material in the micro chromatography column.

According to the technical scheme of the invention, on the first hand, the surface of the chromatographic material is coated with a plurality of layers of metal organic framework materials as the stationary phase, so that the chromatographic material has a deeper internal structure and a larger specific surface area, and the chromatographic separation performance can be obviously improved. In the second aspect, since the magnetic particles are used as the carrier of the chromatographic material, the separation operation can be assisted by external magnetic force, which has the advantage of simplicity and convenience. And in the subsequent process of coating the chromatographic column, the chromatographic material can be fixed in the chromatographic column by utilizing external magnetic force, and the method also has the advantage of simplicity and convenience.

Drawings

For purposes of illustration and not limitation, the present invention will now be described in accordance with its preferred embodiments, particularly with reference to the accompanying drawings, in which:

FIG. 1 is a schematic flow diagram of a method of preparing a chromatographic material according to an embodiment of the invention;

FIG. 2 is a schematic diagram showing a specific process of a method for preparing a chromatography material according to a first embodiment of the present invention;

FIG. 3 is a schematic diagram of a specific process of a method for preparing a chromatographic material according to a second embodiment of the invention;

FIG. 4 is a schematic flow diagram of a method for coating a WeChat chromatography column according to an embodiment of the present invention;

fig. 5 is a detailed process diagram of a coating method of a wechat chromatography column according to an embodiment of the present invention.

Detailed Description

A Metal Organic Framework (MOF) material is a coordination polymer which develops rapidly in recent years, generally takes Metal ions or Metal clusters as connecting points, forms a three-dimensional porous structure through self-assembly of Organic ligands, is a novel porous material, and is widely applied to catalysis, energy storage and separation. Currently, MOFs have become an important research direction for many chemical branches of inorganic chemistry, organic chemistry, and the like. In the embodiment of the invention, magnetic particles are introduced as a stationary phase carrier, and a Layer-by-Layer coating (Layer-by-Layer) mode is utilized to modify the MOF material on the surface, so that the chromatographic material of the multilayer MOF stationary phase is finally obtained, and thus the contact area of gas and the stationary phase can be greatly increased in the chromatographic separation process, and the separation efficiency is increased.

The preparation method of the chromatographic material of the embodiment of the invention mainly comprises the following steps as shown in figure 1:

s101: adding a layer of metal organic framework material stationary phase on the surface of the magnetic particles to realize surface modification, and then cleaning and separating to take out the magnetic particles. The magnetic particles may be magnetic silica particles and/or ferroferric oxide particles. The magnetic particles may have an average particle size of 1 to 10 microns, for example, a batch of magnetic particles having a particle size in the range of 2 to 3 microns may be selected, the average particle size of the magnetic particles being 2.5 microns. The magnetic fine particles may have a spherical, rod-like, or branched shape. The metal-organic framework material is formed by the combination of metal ions and organic groups in solution. The metal ions may be copper ions, zinc ions, chromium ions, etc. The organic group may be a carboxylic acid ligand, an imidazole ligand, or the like. The cleaning process mainly depends on solvents such as methanol or ethanol.

S102: repeating the steps for N times, wherein N is a positive integer. Finally, the magnetic particles with the surfaces coated with N layers of metal organic framework materials can be obtained. The value range of N can be more than or equal to 1 and less than or equal to 60.

For a better understanding of those skilled in the art, the following is illustrated in detail in connection with fig. 2 and 3.

FIG. 2 is a schematic diagram showing the detailed process of the method for preparing a chromatography material according to the first embodiment of the present invention. The goal in this example was to form multiple layers of chromatographic material with HKUST-1 material as the stationary phase on the surface of the magnetic particles. Silicon dioxide microspheres with 2-3 mu m of surface with carboxyl (-COOH) are selected as carriers. Copper acetate (Cu (OAc)₂) Solid and trimesic acid (H)₃BTC) solid was dissolved in ethanol to prepare solutions with concentrations of 1mMol and 0.2mMol, respectively, for use. Firstly, soaking magnetic silicon dioxide microspheres in a copper acetate solution at room temperature for 3 minutes, and taking out the solution; then soaking the magnetic silicon dioxide microspheres in a trimesic acid solution at room temperature for 5 minutes, and taking out the solution; then soaking the magnetic silicon dioxide microspheres in ethanol solution at room temperature to ensure that copper acetate and trimesic acid fully react to form copper 1,3, 5-benzenetricarboxylate(HKUST-1). Finally, the above process is repeated for 20 times, namely, the MOF modification process of 20 layers is completed by using a layer-by-layer coating method.

FIG. 3 is a schematic diagram showing a specific process of a method for preparing a chromatography material according to a second embodiment of the present invention. The objective in this example is to form a multilayer chromatography material with a stationary phase of ZIF-8 material on the surface of magnetic particles. Firstly, preparing 25mMol of methanol solution of zinc nitrate hexahydrate and 50mMol of methanol solution of 2-methylimidazole; then soaking magnetic silicon dioxide microspheres (with carboxyl-COOH) in a mixed solution of the two solutions in a volume ratio of 1:1 for 30 min; then soaking the separated magnetic silica microspheres in a methanol solution for washing for 5min, and then removing the methanol solution; and (3) circulating the steps for 20 times, so that 20 layers of ZIF-8 are formed on the surface of the magnetic silica microsphere.

The chromatographic material of the embodiment of the invention can be prepared by the preparation method of the chromatographic material disclosed in any one of the above publications. The micro-chromatographic column of the embodiment of the invention is coated with the chromatographic material.

Fig. 4 is a schematic flow chart of a coating method of a micro-chromatography column according to an embodiment of the present invention. The coating method of the micro-chromatography column according to the embodiment of the present invention, as shown in fig. 4, may include the steps of:

s201: the chromatographic material disclosed herein is configured as a suspension.

S202: the suspension was injected into a micro-column.

S203: the chromatographic material is immobilized within the mini-column using external magnetic forces.

Fig. 5 is a detailed process diagram of a coating method of a micro-column according to an embodiment of the present invention. As shown in FIG. 5, a suspension was first prepared using an ethanol solution and the magnetic silica particles modified with the HKUST-1 material; injecting the prepared suspension from the inlet of the micro chromatographic column at the speed of 10 mu L/min by using a syringe pump, and stopping injection until liquid drops appear at the outlet of the micro chromatographic column; then, a plate-shaped magnet was placed on the back surface of the micro column (the magnet was located below the micro column in the figure) to allow the magnetic silica particles in the suspension to settle, and after 10 minutes, air was injected into the inlet end of the micro column at a rate of 5 μ L/min by using a syringe pump to discharge the excess ethanol solution inside the column; finally, the coated micro-column was maintained at 100 ℃ for 30 minutes by helium gas, and the ethanol remaining inside the micro-column was completely evaporated. The magnets can be permanent magnets or electromagnets. The electromagnet can flexibly control the strength of the magnetic force.

The micro gas chromatograph comprises a micro chromatographic column disclosed by the invention; and contains permanent magnets or electromagnets for fixing the chromatography material in the micro chromatography column.

In the technical scheme of the embodiment of the invention, on the first hand, the surface of the chromatographic material is coated with a plurality of layers of metal organic framework materials as the stationary phase, so that the chromatographic material has a deeper internal structure and a larger specific surface area, and the chromatographic separation performance can be obviously improved. In the second aspect, since the magnetic particles are used as the carrier of the chromatographic material, the separation operation can be assisted by external magnetic force, which has the advantage of simplicity and convenience. And in the subsequent process of coating the chromatographic column, the chromatographic material can be fixed in the chromatographic column by utilizing external magnetic force, and the method also has the advantage of simplicity and convenience.

The above-described embodiments should not be construed as limiting the scope of the invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions can occur, depending on design requirements and other factors. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.