Laterally diffusing multichannel open-tube column and its preparation method

Abstract

This invention discloses a laterally diffusing multichannel open-tube column and its preparation method. The outer tube of the laterally diffusing multichannel open-tube column is made of a flexible heat-shrinkable material and has channels with a diameter of 3-5 μm. The stationary phase of this laterally diffusing multichannel open-tube column has a regular morphology and uniform pore distribution. The preparation method is convenient, simple, efficient, feasible, and low-cost, providing a methodological reference for the development of ordered, well-structured, large-capacity preparation columns and high-efficiency catalytic reactors.

Description

Technical Field

[0001] This invention relates to the field of chromatographic column preparation, specifically to a transversely diffusing multichannel open-tube column and its preparation method. Background Technology

[0002] Chromatography, after more than a century of development, has become the most important separation and analysis method today. Throughout its history, every revolution and innovation in column structure has greatly promoted theoretical research and practical applications in chromatography. A recently developed multi-open tubular column with transverse diffusion (MOTTD) effectively reduces the significant impact of differences in the inner diameter of the flow channels on column efficiency in non-transverse diffusion columns, while further increasing column capacity, because the analyte can diffuse laterally between the flow channels. The latest theoretical predictions indicate that for a specific size MOTTD column (flow channel inner diameter of 3 μm, channel spacing of 5 μm, and column length greater than 5 cm), its column efficiency is comparable to that of conventional packed columns with particle sizes less than 2 μm, while its minimum column impedance is only 1 / 60 and 1 / 20 of that of packed columns and monolithic columns, respectively. Because this column promises to achieve a harmonious balance between high column efficiency, high column capacity, and high flowability, scientists are calling for breakthroughs in the practical preparation of this ideal MOTTD column with such specific dimensions.

[0003] Due to the stringent requirements for micron-scale control, the most feasible method currently is the fine-filament template method, which involves creating flow channels by occupying space with a fine-filament array template and then removing it. In related research reports, a true MOTTD column was first fabricated by repeatedly inserting and fixing template filaments (minimum diameter 43 μm) in a laser-drilled mold. However, this method is completely unsuitable for ultrafine filaments of a few micrometers, as the threading process becomes extremely difficult and template filament breakage due to pulling is unavoidable. Alternatively, porous carbon electrode materials can be prepared by tightly packing fiber template filaments. However, this rigid extrusion filament positioning method cannot avoid filament bridging, leading to pore leakage and stationary phase collapse. Therefore, there is currently no effective method directly applicable to the fabrication of ultrafine-channel (below 10 μm) MOTTD columns. Summary of the Invention

[0004] The purpose of this invention is to simultaneously solve the two major difficulties in the introduction and positioning of ultrafine template wires in existing methods, and to avoid the problem of wire tangling caused by the compression between template wires. This invention provides a laterally diffusing multi-channel open-ended column and its preparation method. The laterally diffusing multi-channel open-ended column has channels with a diameter of 3-5 μm, a regular morphology of the stationary phase, and a uniform pore distribution. Furthermore, the preparation method of this laterally diffusing multi-channel open-ended column has the advantages of convenient and simple operation, high efficiency, low cost, and good versatility, providing methodological reference for the development of ordered and regular large-capacity preparation columns and high-efficiency catalytic reactors.

[0005] To achieve the above objectives, the present invention provides a laterally diffusing multi-channel open tube column, wherein the outer tube of the laterally diffusing multi-channel open tube column is a flexible heat-shrinkable material tube.

[0006] The present invention also provides a method for preparing a transversely diffusing multichannel open tube column, the method comprising: introducing a quartz template wire into an outer tube, performing heat treatment, then immersing it in a prepolymer solution to carry out a polymerization reaction, and then removing the template;

[0007] The outer tube is a flexible heat-shrinkable material tube.

[0008] In the above technical solution, firstly, the transversely diffusing multichannel open-tube column of the present invention has ultrafine channels of 3-5μm, and the morphology of the stationary phase is regular and the pore distribution is uniform.

[0009] Secondly, this invention provides a pretreatment and etching method for quartz fiber filaments. By using a piranha solution to remove organic matter from the surface of the quartz fiber filaments and increase the number of surface hydroxyl groups, the organic polymer nuclei preferentially attach to the surface of the quartz fiber filaments without being too strong, thus increasing the thickness of the dense layer for filament growth. A low concentration of hydrofluoric acid is used to etch the quartz fiber filaments to obtain quartz template filaments with a diameter of 3 μm, effectively controlling the accuracy of the diameter.

[0010] Meanwhile, the preparation method of this invention utilizes the characteristics of heat shrink tubing, a flexible material. On the one hand, fiber bundles are introduced before the tubing is heated and shrunken, and the internal quartz template wires are tightened by heating, which greatly simplifies the template introduction process and makes the wire bundles achieve an ideal compact distribution. On the other hand, the generation of the organic stationary phase at the polymerization temperature is matched, so that the expansion force of the stationary phase growing outward in the gaps of the quartz template wires and the flexible shrinkage force of the outer tube at this temperature reach a dynamic balance. This balance plays a decisive role in solving the problem of wire fusion of the quartz template wires and controlling the spacing between the quartz template wires. This allows for one-step molding without taking any measures during the polymerization reaction, and prevents the problem of wire fusion of the compactly distributed quartz template wires. It achieves the control of the spacing between the quartz template wires and provides a highly efficient method for preparing ultra-fine channel (diameter 3-5μm) MOTTD columns.

[0011] Furthermore, by adjusting the proportion of porogen in the organic polymer prepolymer solution, this invention determines the range of porogens that provide mechanical strength beneficial to the morphology of the column through-hole array. At the same time, it regulates the non-uniform layer of the fixed phase inherent in the template growth strategy. Through the pretreatment of the template filaments and the improvement of polymerization conditions, its density and thickness are controlled, thereby reducing its adverse effects on lateral diffusion.

[0012] In summary, based on the characteristic that ultrafine template filaments are resistant to compression but not to tension, this invention proposes and develops a new template method for preparing MOTTD columns based on flexible extruded fiber bundles. It provides a comprehensive solution from template introduction, positioning, polymerization to template removal, and pioneers the preparation of laterally diffused multichannel open-tube columns with channel sizes of several micrometers.

[0013] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0014] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0015] Figure 1 Commercial quartz fiber filaments with a diameter of 5 μm (left image) and quartz template filaments with a diameter of 3 μm obtained by etching in Preparation Example 1 (right image);

[0016] Figure 2 To demonstrate the linear relationship between treatment time and the diameter of the quartz template wire obtained under different volume fractions of hydrofluoric acid in Example 1;

[0017] Figure 3 SEM images of quartz template wires after treatment for different volume fractions and time periods, and normal distribution diagram of the diameter of the treated quartz template wires, were obtained to prepare hydrofluoric acid of different volume fractions in Example 1.

[0018] Figure 4 This is a flowchart of the preparation method of the laterally diffusing multichannel open-tube column of Example 1;

[0019] Figure 5 SEM image of the laterally diffusing multichannel open-tube column prepared in Example 9;

[0020] Figure 6 SEM image of the spaced cross section of the transversely diffusing multichannel open tube column prepared in Example 9;

[0021] Figure 7 The image shows a local channel SEM image and a normal distribution diagram of the channel spacing within a laterally diffusing multichannel open-ended column obtained in Example 2.

[0022] Figure 8 SEM image of the laterally diffusing multichannel open-tube column prepared in Example 1;

[0023] Figure 9 SEM image of the laterally diffusing multichannel open-tube column prepared in Example 2;

[0024] Figure 10 The images show SEM images of local channels within a laterally diffusing multichannel open-ended column and normal distribution diagrams of channel diameters obtained in Example 2.

[0025] Figure 11 SEM images of local channels within a laterally diffusing multichannel open-ended column prepared in Examples 1, 4-5, and Comparative Examples 1-2;

[0026] Figure 12 The image shows the actual contents of the transversely diffusing multichannel open-tube column core and the stainless steel outer tube of the chromatographic column in Example 3.

[0027] Figure 13 Example 3 shows the column pressure-flow rate curves of a transversely diffusing multichannel open-circuit column using methanol as the mobile phase (left): the transversely diffusing multichannel open-circuit column prepared in Example 2; (right): the transversely diffusing multichannel open-circuit column with a channel diameter of 5 μm prepared in Example 1.

[0028] Figure 14 This is a partial SEM image of the laterally diffusing multichannel open-tube column prepared in Example 3;

[0029] Figure 15 The diagram shows the drilling of the outer tube in Examples 1 and 2. Detailed Implementation

[0030] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0031] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0032] The present invention provides a transversely diffusing multi-channel open tube column, wherein the outer tube of the transversely diffusing multi-channel open tube column is a flexible heat-shrinkable material tube.

[0033] The transversely diffusing multichannel open-tube column of the present invention has ultrafine channels with a diameter of 3-5μm, and the stationary phase has a regular morphology and uniform pore distribution.

[0034] In a preferred embodiment of the present invention, the diameter of each channel of the laterally diffusing multichannel open tube column is 3-5 μm.

[0035] The present invention also provides a method for preparing a transversely diffusing multichannel open tube column, the method comprising: introducing a quartz template wire into an outer tube, performing heat treatment, then immersing it in a prepolymer solution to carry out a polymerization reaction, and then removing the template;

[0036] The outer tube is a flexible heat-shrinkable material tube.

[0037] The preparation method of the present invention has the advantages of being convenient and simple to operate, highly efficient and feasible, and low in cost, and has good universality.

[0038] In a preferred embodiment of the present invention, in order to provide a certain shrinkage force and an expandable range during the polymerization reaction, the quartz template filaments can be ideally distributed by extrusion, and the outer tube is a flexible heat-shrinkable material tube.

[0039] In a preferred embodiment of the present invention, the flexible heat-shrinkable material tube can be made of a material commonly used in the art that has flexible heat-shrinkable properties, such as the outer tube being selected from polyvinyl chloride heat-shrinkable tubing, polyethylene terephthalate heat-shrinkable tubing, and elastic silicone tubing.

[0040] In a preferred embodiment of the present invention, the inner diameter of the flexible heat-shrinkable material tube is 440-6000 μm, and the inner diameter of the flexible heat-shrinkable material tube after heating and shrinking is 220-3000 μm.

[0041] In a preferred embodiment of the present invention, in order to make the prepared transversely diffusing multichannel open tube column have channels with a diameter of 3-5 μm, the diameter of the quartz template wire is 3-5 μm.

[0042] In a preferred embodiment of the present invention, in order to achieve a dynamic balance between the expansion force between the quartz template filaments and the contraction force of the outer tube during the in-column polymerization process, and to avoid the problem of filament tangling caused by hard extrusion through this balance, the total diameter of the quartz template filaments is 1-1.35 times the inner diameter of the contracted outer tube, wherein the total diameter is the sum of the diameters of the quartz template filaments introduced into the outer tube.

[0043] In a preferred embodiment of the present invention, in order to achieve a dynamic balance between the expansion force between the template wires and the contraction force of the outer tube during the in-column polymerization process, and to avoid the wire tangling problem caused by hard extrusion through this balance, the total diameter of the quartz template wires is 1.2 times the inner diameter of the contracted outer tube.

[0044] In a preferred embodiment of the present invention, in order to shrink the outer tube and allow the template wires inside the outer tube to reach an ideal stacking state, the heat treatment conditions include: the heat treatment temperature is at least 20°C higher than the shrinkage temperature of the outer tube.

[0045] In a preferred embodiment of the present invention, the soaking time is 10-16 hours to ensure complete polymerization.

[0046] In a preferred embodiment of the present invention, the soaking time is 12 hours to ensure that the polymerization reaction is complete.

[0047] In a preferred embodiment of the present invention, as the temperature increases, the proportion of mesoporous components in the stationary phase increases significantly, and the specific surface area also increases. This improves the analytical performance of the laterally diffusing multichannel open-cell column. Temperature primarily affects the number of polymer nuclei formed at the start of the polymerization reaction, thus influencing the pore size distribution. At higher temperatures, the initiator decomposes rapidly, generating more free radicals simultaneously, resulting in more polymer nuclei. This increase in the number of nuclei leads to a decrease in the size of each particle, and the crosslinking of smaller particles produces smaller pore sizes. To control the reaction rate, the polymerization conditions include: a temperature of 50-70°C and a time of 20-30 hours.

[0048] In a preferred embodiment of the present invention, in order to control the reaction rate, the conditions for the polymerization reaction include: a temperature of 60°C and a time of 24 hours.

[0049] In a preferred embodiment of the present invention, in order to clean the template of the transversely diffusing multichannel open column, the template removal method includes immersing the transversely diffusing multichannel open column after the polymerization reaction in hydrofluoric acid for 2-3 days.

[0050] In a preferred embodiment of the present invention, the transversely diffusing multichannel open column after template removal is rinsed with deionized water until the eluent is neutral, and finally the unreacted prepolymer is washed away with methanol.

[0051] In a preferred embodiment of the present invention, the method for preparing the quartz template filament includes: soaking quartz fiber filaments in a piranha solution and then subjecting them to heat treatment.

[0052] In a preferred embodiment of the present invention, in order to further reduce the channel diameter of the transversely diffusing multichannel open tube column, the diameter of the quartz fiber filament is 4-7 μm.

[0053] In a preferred embodiment of the present invention, in order to further reduce the channel diameter of the transversely diffusing multichannel open tube column, the diameter of the quartz fiber filament is 5 μm.

[0054] In a preferred embodiment of the present invention, the method for preparing the piranha solution includes: slowly adding a 30% (v / v) aqueous solution of hydrogen peroxide to cold concentrated sulfuric acid, wherein the volume ratio of the aqueous solution of hydrogen peroxide to the concentrated sulfuric acid is 3:7.

[0055] In a preferred embodiment of the present invention, the heat treatment conditions include: oil bath; temperature of 70-100℃; and time of 30-60 min.

[0056] In a preferred embodiment of the present invention, the heat treatment conditions include: oil bath; temperature of 90°C; and time of 60 min.

[0057] In a preferred embodiment of the present invention, since the smallest diameter of commercially available quartz fiber filaments is 4μm, and the diameter of the quartz fiber filaments used in the present invention is 5μm, in order to obtain 3μm quartz template filaments, the quartz template filaments that have been soaked in piranha solution and heat-treated can be etched. The etching conditions include: immersing the heat-treated quartz fiber filaments in a mixed solution of hydrofluoric acid and water, and shaking for 5-50 minutes.

[0058] In a preferred embodiment of the present invention, the volume fraction of hydrofluoric acid solution in the mixed solution of hydrofluoric acid and water is 5%-30%.

[0059] In a preferred embodiment of the present invention, the volume fraction of hydrofluoric acid solution in the mixed solution of hydrofluoric acid and water is 10%.

[0060] In a preferred embodiment of the present invention, the volume fraction of hydrofluoric acid in the hydrofluoric acid solution is 45%-55%.

[0061] In a preferred embodiment of the present invention, the volume fraction of hydrofluoric acid in the hydrofluoric acid solution is 48%-51%.

[0062] In a preferred embodiment of the present invention, the volume fraction of hydrofluoric acid in the hydrofluoric acid solution is 50%.

[0063] In a preferred embodiment of the present invention, the prepolymer liquid contains monomers, crosslinking agents, pore-forming agents, and polymerization initiators.

[0064] In a preferred embodiment of the present invention, in order to make the stationary phase of the prepared transversely diffusing multichannel open column have a regular morphology and a certain mechanical strength, the volume ratio of the monomer, crosslinking agent and pore-forming agent is 2:1-3:5.5-7.

[0065] In a preferred embodiment of the present invention, the amount of the polymerization initiator is 0.5wt%-2wt% of the monomer.

[0066] In a preferred embodiment of the present invention, the amount of the polymerization initiator is 1% of the mass fraction of the monomer.

[0067] In a preferred embodiment of the present invention, in order to provide expansion force to the quartz template filament during the polymerization reaction, it should also have a certain mechanical strength, a high specific surface area and modifiable sites, and be compatible with the removal method of the quartz template filament so as not to be destroyed in the process. The monomer is one or more of glycidyl methacrylate, bisphenol A epoxy vinyl resin, polyacrylamide and polystyrene.

[0068] In a preferred embodiment of the present invention, in order to make the stationary phase of the prepared transversely diffusing multichannel open column have a regular morphology and a certain mechanical strength, the crosslinking agent is ethylene glycol dimethacrylate.

[0069] In a preferred embodiment of the present invention, the pore-forming agent is a combination of cyclohexanol and 1-dodecyl alcohol or a combination of propanol, 1,4-butanediol and water.

[0070] In a preferred embodiment of the present invention, the polymerization initiator may be a conventional polymerization initiator in the art, such as one or more selected from azobisisobutyronitrile, azobisisoheptanenitrile, and dimethyl azobisisobutyrate.

[0071] The present invention will be described in detail below through examples.

[0072] Preparation Example 1

[0073] Preparation of quartz template wire:

[0074] 1) Surface treatment: Take a quartz fiber filament with a diameter of 5μm, immerse it in Piranhak solution, the surface of the filament bundle quickly turns brownish-black and bubbles are released, transfer it to an oil bath and heat at 90℃ for 1 hour, the color fades and no more bubbles are released, rinse the surface-treated quartz fiber filament with deionized water until neutral, and blow dry in a nitrogen stream to obtain a quartz template filament with a diameter of 5μm;

[0075] 2) Etching: Prepare a series of mixed solutions (5%, 10%, 15%, 20%, 25%, 30%) of hydrofluoric acid and water in 200 mL in a plastic bottle. Fix both ends of the 5 μm diameter quartz template wire from step 1) into the solution and place it on a shaker for reaction. After a certain time interval (5 min, 10 min, 15 min, 20 min, 30 min, 40 min, 50 min), take out a portion, rinse with ultrapure water until neutral to terminate the reaction, and dry it in a nitrogen stream.

[0076] Table 1. Average diameter of quartz template wire after treatment with different HF concentrations and time.

[0077]

[0078]

[0079] As shown in Table 1, when the volume fraction of hydrofluoric acid is >15%, the reaction rate with the surface-treated 5μm diameter quartz template wire at room temperature is too fast, resulting in poor uniformity of the diameter of the obtained quartz template wire. A large number of non-uniform quartz template wires will have a negative effect on column efficiency. On the other hand, the reaction rate of the 5% volume fraction hydrofluoric acid solution is too slow. When processing quartz template wires in large quantities, the solute content is low, requiring a large amount of solution and making the preparation cumbersome.

[0080] Combined Figure 2 The curve shows that the reaction rate of a 10% hydrofluoric acid solution is relatively slow and has the best linear relationship.

[0081] Combination Figure 3 Based on the visual morphology and SEM images of the quartz template wire and the difficulty of subsequent operations (excessive fineness can easily lead to a large number of wire breakages), the processing time was determined to be 30 minutes, and the diameter of the quartz template wire was controlled at 3μm.

[0082] Example 1

[0083] (1) Add glycidyl methacrylate (GMA), ethylene glycol dimethacrylate (EDMA), cyclohexanol and 1-dodecyl alcohol to a glass bottle in a volume ratio of 25%:15%:55%:5%, then add azobisisobutyronitrile (AIBN) with a weight of 1wt% GMA, sonicate for 10 min until mixed evenly, add AIBN and sonicate again for 10 min until AIBN is completely dissolved, purge the prepolymer solution with nitrogen to remove oxygen for 15 min, and store in a refrigerator at 4-6℃.

[0084] (2) The 5 μm diameter quartz template filament after surface treatment in Preparation Example 1 was introduced into a 20 cm long PET heat shrink tube (Tyco Electronics Co., Ltd.) with a diameter of 6 mm before shrinkage and heated to shrink. In order to better fill the cavity after column expansion with prepolymer liquid and avoid affecting column shape, holes (0.5 cm) were drilled in a spiral pattern at intervals of about 2 cm on the outer tube. The total diameter of the introduced quartz template filament was 1.2 times the inner diameter of the heat shrink tube after shrinkage.

[0085] (3) Immerse the whole tube into a Pasteur pipette filled with the prepolymer liquid prepared in step (1), let it stand for 12 hours until the quartz template filament in the heat shrink tube is moistened, remove the air bubbles by evacuating, sonicate for 30 seconds, repeat the evacuation process until no air bubbles are removed, seal the pipette and put it in an oven at 60°C for 24 hours.

[0086] (4) After the reaction is complete, the column is removed from the stationary phase, immersed in a container containing hydrofluoric acid, and the container is placed in a cold water bath for 3 days to remove the quartz template wire. The column is then rinsed with deionized water until the eluent is neutral. Finally, the unreacted prepolymer is washed away with methanol to obtain a transversely diffused multichannel open tube column with a channel diameter of 5 μm, denoted as B1.

[0087] Example 2

[0088] The method described in Example 1 was implemented, except that in step (2), the 3 μm diameter quartz template wire obtained by etching in Example 1 was introduced into a 20 cm long PET heat shrink tube (Tyco Electronics Co., Ltd.) with a diameter of 6 mm before shrinkage and heated to shrink. In order to better fill the cavity after the column expansion with prepolymer liquid and avoid affecting the column shape, holes (0.5 cm) were drilled in a spiral pattern at intervals of about 2 cm on the outer tube. The total diameter of the introduced quartz template wire was 1.2 times the inner diameter of the heat shrink tube after shrinkage, resulting in a multi-channel open tube column with a channel diameter of 3 μm that can diffuse laterally, denoted as B2.

[0089] Example 3

[0090] The method described in Example 1 was implemented, except that an elastic silicone tube with an outer tube length of 10cm and an inner diameter of 5mm was used to obtain a multi-channel open tube column with a channel diameter of 5μm that can diffuse laterally, denoted as B3.

[0091] Depend on Figure 8 Local SEM image of the laterally diffusing multichannel open-ended column obtained in Example 1. Figure 9 Local SEM images of the laterally diffusing multichannel open-ended column obtained in Example 2 and Figure 14 The partial SEM images of the laterally diffusing multichannel open-ended column prepared in Example 3 show that the morphology of the laterally diffusing multichannel open-ended column prepared in Example 3 using elastic silicone tubing as the outer tube is basically the same as that of the laterally diffusing multichannel open-ended columns prepared in Examples 1-2 using PET heat-shrink tubing as the outer tube; the morphology of the laterally diffusing multichannel open-ended column with a channel diameter of 3μm in Example 2 is basically the same as that of the laterally diffusing multichannel open-ended column with a through-hole diameter of 5μm in Example 3.

[0092] Example 4

[0093] The method described in Example 1 was carried out, except that in step (1), the ratio of glycidyl methacrylate (GMA), ethylene glycol dimethacrylate (EDMA), cyclohexanol and 1-dodecyl alcohol in the prepolymer solution was 30%:20%:45%:5%, resulting in a multi-channel open column with a channel diameter of 5 μm that can diffuse laterally, denoted as B4.

[0094] Example 5

[0095] The method described in Example 1 was carried out, except that in step (1), the ratio of glycidyl methacrylate (GMA), ethylene glycol dimethacrylate (EDMA), cyclohexanol and 1-dodecyl alcohol in the prepolymer solution was 20%:15%:60%:5%, resulting in a multi-channel open column with a channel diameter of 5 μm that can diffuse laterally, denoted as B5.

[0096] Example 6

[0097] The method described in Example 1 was implemented, except that the preparation method of the prepolymer solution in step (1) was as follows: 20g of bisphenol A diglycidyl ether (BADE), 20mL of 1,4-dioxane and a three-necked flask were taken, heated to 60°C in an oil bath under magnetic stirring, 0.4g of tetrabutylammonium bromide was slowly added, and the temperature was continued to 80°C. 8.6mL of methacrylic acid was slowly added dropwise, and the temperature was heated to 90°C. The reaction was carried out for 4.5h to obtain a VER solution. EDMA and VER were added to a glass bottle at a volume ratio of 1:3. Propanol, 1,4-butanediol and water were added to the glass bottle at a volume ratio of 45%:45%:10%. The mixture was sonicated for 10min until it was homogeneous. AIBN with a weight of 1wt% VER was added. The mixture was sonicated again for 10min until the AIBN was completely dissolved in the prepolymer solution. Nitrogen was bubbled into the prepolymer solution to remove oxygen for 15min. The solution was stored in a refrigerator at about 4°C for later use to obtain a multi-channel open column with a channel diameter of 5μm that can diffuse laterally, which was designated as B6.

[0098] Example 7

[0099] The method described in Example 1 was carried out, except that the polymerization temperature in step (2) was 50°C, resulting in a multi-channel open column with a channel diameter of 5 μm that can diffuse laterally, denoted as B7.

[0100] Example 8

[0101] The method described in Example 1 was carried out, except that the polymerization temperature in step (2) was 70°C, resulting in a multi-channel open column with a channel diameter of 5 μm that can diffuse laterally, denoted as B8.

[0102] Example 9

[0103] The method described in Example 1 was carried out, except that in step (2), the 5 μm diameter quartz template filament after surface treatment in Example 1 was introduced into a 15 cm long PE heat shrink tubing (Tyco Electronics Co., Ltd.) with a diameter of 440 μm before shrinkage and heated to shrink. The total diameter of the introduced quartz template filament was 1.2 times the inner diameter of the shrunken heat shrink tubing, resulting in a 5 μm diameter, laterally diffused multi-channel open tube column, denoted as B9.

[0104] Comparative Example 1

[0105] The method described in Example 1 was carried out, except that in step (1), the ratio of glycidyl methacrylate (GMA), ethylene glycol dimethacrylate (EDMA), cyclohexanol and 1-dodecyl alcohol in the prepolymer solution was 25%:5%:65%:5%, resulting in a multi-channel open column with a channel diameter of 5 μm that can diffuse laterally, denoted as D1.

[0106] Comparative Example 2

[0107] The method described in Example 1 was carried out, except that in step (1), the ratio of glycidyl methacrylate (GMA), ethylene glycol dimethacrylate (EDMA), cyclohexanol and 1-dodecyl alcohol in the prepolymer solution was 20%:5%:70%:5%, resulting in a multi-channel open column with a channel diameter of 5 μm that can diffuse laterally, denoted as D2.

[0108] Depend on Figure 11 SEM images of the local channels within the laterally diffusing multichannel open-cell columns prepared in Examples 1, 4-5, and Comparative Examples 1-2 show that, when preparing laterally diffusing multichannel open-cell columns containing the same filament bundles with a channel diameter of 5 μm, in Comparative Example 2, when the volume fraction of the porogen in the prepolymer solution was 75%, the resulting material was composed of large-particle polymer crosslinks, resulting in high porosity and insufficient mechanical strength to support the flow channels, leading to significant deformation and collapse of the flow channels. In Comparative Example 1, when the volume fraction of the porogen in the prepolymer solution was reduced to 70%, although complete flow channels could be formed, the mechanical strength was still insufficient. The results were poor, with frequent core cracking, making it difficult to apply. In Example 4, when the volume fraction of the porogen in the prepolymer solution was 50%, the particles of the resulting material were very small, the degree of cross-linking was high, and the material showed signs of caking. In the early stages of particle formation, the particles were small and the expansion was not obvious, which led to some template filaments not separating, which was not conducive to the complete formation of the column. In Example 5, when the volume fraction of the porogen was adjusted to 65%, the overall mechanical strength basically met the requirements, and the stationary phase was composed of larger particles. In Example 1, when the volume fraction of the porogen was 60%, the particle size was significantly reduced, and the mechanical strength was further increased.

[0109] Detection Example 1

[0110] To quantify the uniformity of channel spacing, this invention selects three images with the same magnification, randomly selects 50 channel samples for each image using NanoMeasurer, performs normal distribution fitting, and calculates their average spacing and relative standard deviation.

[0111] Table 2 shows the channel spacing data and the relative standard deviation of the channel spacing in the laterally diffusing multi-channel open-ended tubular column in Example 2.

[0112]

[0113] Depend on Figure 7 According to the SEM images of local channels in the transversely diffusing multichannel open-ended column prepared in Example 2, the normal distribution diagram of channel spacing, and the data in Table 2, the average channel spacing of the transversely diffusing multichannel open-ended column prepared in Example 2 of this invention is 2.21 μm, and the maximum relative standard deviation is 6.04%, indicating that the channel spacing of the transversely diffusing multichannel open-ended column of this invention has good uniformity.

[0114] Detection Example 2

[0115] Using the treated template wire, a transversely diffused multichannel open-tube column was prepared in the same way. The column core was sealed in a 15cm stainless steel outer tube with epoxy resin. After the epoxy resin cured, both ends were cut off, and its morphology was observed by SEM.

[0116] Table 3 shows the channel diameter data and relative standard deviation of a laterally diffusing multichannel open-ended column with a channel diameter of 3 μm.

[0117]

[0118] Combination Figure 10 The SEM images of local channels and the normal distribution diagram of channel diameters in the transversely diffusing multichannel open-ended column prepared in Example 2, along with the data in Table 3, show that the average diameter of the channels in the transversely diffusing multichannel open-ended column prepared in Example 2 is 3.18 μm, and the maximum relative characterization deviation is only 2.16%, indicating that the uniformity of the through holes in the transversely diffusing multichannel open-ended column of Example 2 of the present invention is good.

[0119] Detection Example 3

[0120] The mechanical stability of the laterally diffusing multichannel open column of the present invention was determined by using the laterally diffusing multichannel open column prepared in Examples 1 and 2 of the present invention, which was sealed in an epoxy resin in a 15 cm long stainless steel chromatographic column, and washed with methanol at 0.2 mL / min until the baseline was stable, and the column pressure-flow rate curve was measured.

[0121] Depend on Figure 13 The column pressure-flow rate curves of a laterally diffusing multichannel open-circuit column with methanol as the mobile phase are shown in the following figures: (Left) laterally diffusing multichannel open-circuit column prepared in Example 2; (Right) laterally diffusing multichannel open-circuit column with a channel diameter of 5 μm prepared in Example 1. It can be seen that when methanol is used as the mobile phase, the column pressure of the laterally diffusing multichannel open-circuit column increases with increasing flow rate. At lower flow rates (<2 mL / min), there is a good linear relationship between the two. As the flow rate continues to increase, the narrow-aperture stationary phase begins to collapse, causing blockage of the vias, and the column pressure rises sharply, eventually approaching that of a monolithic organic polymer column.

[0122] Detection Example 4

[0123] Using pure water as the mobile phase, the permeability of the chromatographic column with a channel diameter of 5 μm in Example 3 was determined.

[0124] The permeability of a chromatographic column is usually determined by examining the relationship between flow rate and column pressure under a 100% pure water mobile phase, and can be expressed using the Darcy equation:

[0125] L=uηM / ΔP

[0126] Where u is the linear velocity of pure water (m / s); η is the viscosity of the mobile phase (Pa·s); L is the column length (m); and ΔP is the column pressure (Pa). When u and η are constant, the permeability coefficient L is inversely proportional to ΔP / M.

[0127] When the flow rate of pure water is 0.8 mL / min, the measured column pressure is 0.6 MPa. The flow rate divided by the column cross-sectional area is converted to a linear velocity of 1.04 × 10⁻⁶. -3 The viscosity of pure water at 20℃ is 1.01 × 10⁻⁶ m / s. -3 Pa·s.

[0128] Using the above formula, the permeability of the laterally diffusing multi-channel open-tube column of the present invention is calculated to be 1.75 × 10⁻⁶. - 13 m 2 The flow rate is much larger than that of previously reported monolithic columns, indicating that the laterally diffusing multichannel open-tube column of the present invention has strong mechanical properties in this flow rate range and is suitable for analytical applications at high flow rates in liquid chromatography.

[0129] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0130] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0131] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method of making a laterally diffusive multi-channel open tubular column, characterized by, The preparation method includes: introducing a quartz template wire into an outer tube, heat-treating it, then immersing it in a prepolymer solution to carry out a polymerization reaction, and then removing the template; The outer tube is a flexible heat-shrinkable material tube; The laterally diffusing multichannel open-ended column has channels with a diameter of 3-5 μm.

2. The production method according to claim 1, characterized by, The flexible heat-shrinkable material tubing is selected from one of polyvinyl chloride heat-shrinkable tubing, polyethylene terephthalate heat-shrinkable tubing, and elastic silicone tubing. The inner diameter of the flexible heat-shrinkable material tube is 440-6000 μm; The diameter of the quartz template wire is 3-5 μm.

3. The production method according to claim 1 or 2, characterized by, The total diameter of the quartz template wire introduced into the outer tube is 1-1.35 times the inner diameter of the shrunken outer tube.

4. The method of claim 1, wherein, The total diameter of the quartz template wire introduced into the outer tube is 1.2 times the inner diameter of the shrunken outer tube.

5. The preparation method according to claim 1, characterized in that, The conditions for the heat treatment include: the heat treatment temperature is at least 20°C higher than the complete shrinkage temperature of the outer tube; The soaking time is 10-16 hours.

6. The preparation method according to claim 1, characterized in that, The soaking time is 12 hours.

7. The preparation method according to claim 1, characterized in that, The conditions for the polymerization reaction include: a temperature of 50-70℃ and a time of 20-30h; The method for removing the template includes immersing the transversely diffusing multichannel open column after the polymerization reaction in hydrofluoric acid for 2-3 days.

8. The preparation method according to claim 1, characterized in that, The conditions for the polymerization reaction include: a temperature of 60°C and a time of 24 hours.

9. The preparation method according to claim 1, characterized in that, The method for processing the quartz template filaments includes: immersing the quartz fiber filaments in a piranha solution and then subjecting them to heat treatment; The diameter of the quartz fiber filament is 4-7 μm; The heat treatment conditions include: oil bath; temperature of 70-100℃; time of 30-60 min.

10. The preparation method according to claim 9, characterized in that, The diameter of the quartz fiber filament is 5 μm; The heat treatment conditions include: oil bath; temperature of 90℃; time of 30-60 min.

11. The preparation method according to claim 1, characterized in that, The prepolymer solution contains monomers, crosslinking agents, pore-forming agents, and polymerization initiators; The volume ratio of the monomer, crosslinking agent, and porogen is 2:1-3:5.5-7; The amount of the polymerization initiator is 0.5wt%-2wt% of the monomer.

12. The preparation method according to claim 11, characterized in that, The monomer is selected from one or more of glycidyl methacrylate, ethylene glycol dimethacrylate, polyacrylamide, and polystyrene; The crosslinking agent is ethylene glycol dimethacrylate; The pore-forming agent is a combination of cyclohexanol and 1-dodecyl alcohol or a combination of propanol, 1,4-butanediol and water.

Images