JPH0134345B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to adsorbent materials for chromatography. More specifically, the adsorbent material for chromatography is made by adding and mixing a copolymer of a vinyl monomer with a hydrophilic group and a vinyl monomer with a hydrophobic group as a binder to various adsorbents for chromatography. Involved. Commonly used adsorbents for chromatography include silica gel, diatomaceous earth, aluminum oxide, magnesium silicate, cellulose, polyamide, and polycarbonate. However, when a layer consisting of these adsorbents alone is coated on a support, sufficient adhesion is not obtained and the layer is unstable against mechanical pressure. When attempting to carry out graphimetry, there is a problem in that the development of the chromatogram is incomplete due to parts of the layers peeling off in the liquid. For this solution, for example, starch,
The use of various adhesives and binders such as casts, CMC, and polyvinyl alcohol has been proposed. It is also known that addition of finely ground silicon dioxide or aluminum oxide increases bond strength. However, no inorganic adhesive is known that provides an adsorption layer with even better impact abrasion resistance. That is, no matter how much the ratio of cast to adsorbent is adjusted, some casts do not provide impact abrasion resistance. On the contrary, when a cast is used, the sample to be developed forms a poorly soluble calcium salt or sulfate, which is firmly held at the starting point of the chromatogram, thereby causing the disadvantage that development of the chromatogram is inhibited. Additionally, adsorbents containing casts have the disadvantage that they begin to harden quickly after mixing and require a great deal of experience in handling. On the other hand, conventional organic binders have the disadvantage that they cannot be sprayed with conventional detection reagents after development.
That is, for example, if a strong acid is sprayed and then heated, the adsorption layer turns black, making it extremely difficult, if not impossible, to detect the developed spot. Japanese Patent No. 747542 discloses a method using polyacrylic acid, polymethacrylic acid, ethylene-maleic acid copolymers, and salts thereof as binders that do not have the above-mentioned drawbacks. When 0.1 to 10% by weight of at least one selected from these binders is added to conventional adsorbents, these binders confer high resistance to abrasion and good resistance to corrosive agents. It is said to have the following. However, such carboxyl group-containing polymer binders are usually used in the form of salts, and therefore have the disadvantage of extremely poor water resistance. This is because salts such as polyacrylic acid and polymethacrylic acid swell and dissolve excessively in the presence of water. That is, the result is that even the tightly adhered layer dissolves and separates from the support under the action of water. In thin layer chromatography, water or a mixture of water and other solvents is overwhelmingly used as the solvent system;
A water-resistant adsorbent layer is essential. Also, for example, from adsorbent layers that are not water-resistant, the binder is eluted into water-containing solvent systems, which has a particularly detrimental effect in the analytical detection of substances with Rf values greater than 0.7. Furthermore, with an adsorbent layer that is not water resistant, it is not possible to use an aqueous detection reagent on the developed chromatogram, and the spots on the chromatogram become blurred over time, making it difficult to identify them. , which becomes an obstacle when saving chromatograms. In Japanese Patent Application Publication No. 1987-87951,
Furthermore, as a method to solve these problems, the adsorbent is coated on a support using polyacrylate and/or polymethacrylate as a binder, and then washed and dried. A method of increasing water resistance is shown. According to this method, a chromatographic adsorbent layer containing polyacrylates and/or polymethacrylates as binder is prepared separately and then treated with dilute acid in water or an alcoholic solvent. This requires extremely complex pretreatment operations, including treatment for several minutes to several hours, repeated washing in demineralized water, and drying. The operation process becomes complicated and long, and acid treatment leaves free carboxyl groups in the adsorbent layer, and the acidification also changes the adsorption properties of basic substances. It's definitely not a good thing. As a result of intensive research, the present inventor has found that by adding 1 to 10% by weight of the copolymer of the present invention to an adsorbent commonly used for chromatography, it has extremely high mechanical strength and is an excellent adhesive. The present invention was completed based on the knowledge that it is possible to obtain a chromatography layer that is also water resistant. That is, the adsorbent material for chromatography of the present invention contains 99 to 90% by weight of silica gel, diatomaceous earth, aluminum oxide, magnesium silicate, calcium phosphate, cellulose, polyamide, or polycarbonate as an adsorbent, and a hydrophilic group as a binder. and 1 to 10% by weight of one or more copolymers selected from vinyl copolymers containing hydrophobic groups in the same polymer. The separation ability of the adsorbent is not impaired at all by the addition of the copolymer of the present invention. The extremely good performance of the adsorbent material for chromatography of the present invention is listed below.
That is, it has good adhesion to the glass or plastic plates normally used as supports, has sufficient resistance to frictional impact, does not need to be transported in a special container, and there is no risk of damaging the adsorbent layer. They can be stored and transported by stacking them directly on top of each other. Also, the adsorbent layer can be sprayed with a mineral acid, such as concentrated sulfuric acid, and then heated without any damage. Because of this advantage, many detection reagents commonly used in thin layer chromatography, such as phosphoric acid, perchloric acid, antimony trichloride, anisaldehyde/sulfuric acid, phosphotungstic acid, and iodine, can be used without any problems. . The binding agent of the present invention is particularly suitable for detecting amino acids with ninhydrin. Another advantage of the binder of the invention is that it is completely insoluble in organic solvents and is water resistant so that it will not be leached from the layer when aqueous developing solvents are used. Thus, the present invention provides very good impact abrasion resistance, water resistance, surface smoothness, insolubility to organic solvents, good adhesion to substrates, and sulfuric acid by using the binder of the present invention. Even with the use of powerful detection reagents such as, it provides excellent efficacy and performance, such as no discoloration at all. These effects of using the binder of the invention are completely unexpected from the prior art. The binder of the present invention is a high molecular weight copolymer prepared from a vinyl monomer containing a hydrophilic group and a vinyl monomer containing a hydrophobic group. Examples include acrylamide-methyl acrylate or ethyl acrylate copolymer, and acrylamide-methyl methacrylate copolymer. If the amount of acrylamide, which is a hydrophilic monomer, in the high molecular weight copolymer is too large, the result will be unsatisfactory in terms of improving water resistance, which is one of the characteristics of the present invention. If the amount is too large, the polymer will become insoluble in water, making it undesirable as a binder for the purpose of the present invention. That is, the monomer ratio of the high molecular weight copolymer is, for example, 70 to 85 parts of acrylamide and 30 to 15 parts of methyl acrylate or ethyl acrylate, or 80 to 85 parts of acrylamide.
~90 parts and 20-10 parts of methyl methacrylate are preferred. Incidentally, silica gel used in thin layer chromatography is neutral or weakly acidic, but aluminum oxide is weakly basic, so when used as an adsorbent, it is a binder of the present invention. The high molecular weight copolymer is dissolved in water before being mixed with the adsorbent, and the pH is adjusted to an appropriate level before use. The adsorbent material of the present invention may contain any of the various additives commonly used in thin layer chromatography. For example, 2 to 10 inorganic adhesives
They can also be added to the adsorbent material of the invention in proportions by weight. Suitable inorganic adhesives include, for example, fine-grained silica under the trade name "Aerosil" manufactured by Nippon Aerosil Co., Ltd., or colloidal silica under the trade name "Snowtex" manufactured by Nissan Chemical Co., Ltd., which are especially suitable for addition to silica gel and interstitial soil. When aluminum oxide is used, ultrafine alumina colloid manufactured by Nissan Chemical Co., Ltd. under the trade name "Alumina Sol" is preferred. In addition, in order to better identify substances that absorb ultraviolet light, inorganic phosphors and inorganic mixed phosphors (Analytical Chemistry Vol. 19)
518 [1970]) may be added. The adsorbent material of the present invention can be prepared by conventional methods.
First, the binder is dissolved in water, and the pH is adjusted to adjust the water solubility of the binder. Next, the adsorbent is added and the binder and the adsorbent are sufficiently mixed by shaking or stirring to prepare a uniform coating solution. The adsorption material thus obtained is applied onto a support, air-dried, and then activated by a known method, for example, by heating at 100-120°C. As the method for producing the high molecular weight copolymer used in the present invention, an aqueous solution polymerization method, which is a general polyacrylamide polymerization method, can be applied. In this case, the aqueous solution of the polymer can be used as a binder as it is, but in order to remove unreacted monomers, it can be isolated as a powder by injecting the aqueous solution into a polymer inert solvent such as methanol or acetone. You can also do it. More specifically, an acrylamide monomer and an acrylic ester (methyl ester, ethyl ester, etc.) monomer or an acrylamide monomer and a methacrylic ester monomer are dissolved in degassed distilled water at a desired monomer ratio. The appropriate monomer concentration at this time is 5 to 10% by weight. Subsequently, a polymerization initiator, Wako Pure Chemical Industries, Ltd. product V-50 (2,2'-azobis-(2-
(amidinopropane) dihydrochloride) or V-56 (2,2'-azobis(N,N'-dimethyleneisobutyramidine) dihydrochloride), etc.
Add 0.05% by weight, introduce _N2 gas, and conduct the reaction at a temperature of 45-60°C for 4-6 hours. V-56 is V-50
The activity of the catalyst is higher, the amount added can be less than half that of V-50, and the reaction temperature can also be lowered. This is particularly suitable for the method of manufacturing the binder of the present invention which requires a high molecular weight copolymer. This reaction solution can be used as a binder as it is, but since it is necessary to remove unreacted monomers, crystallization is performed using a polymer-insoluble solvent such as methanol or acetone in a conventional manner, and then thoroughly washed. It can be isolated as a white powder by drying under reduced pressure at 50-70°C. Hereinafter, the present invention will be further explained in Examples. Example 1 Manufacture of binder 1 A four-necked flask was equipped with a stirrer and a N2 gas inlet pipe, and 200 _ml of degassed distilled water, acrylamide monomer, and ethyl acrylate monomer were added in the proportions shown in the following table to a monomer concentration of 5. %. Additionally, 5 mg of V-50 as an initiator
(0.05% vs. monomer amount) and N ₂ at 5-10 °C.
Introduce gas for 10 minutes. Thereafter, the internal temperature was adjusted to 55° C., and the reaction was carried out for 5 hours under a N ₂ gas stream. After the reaction, the viscous aqueous solution was diluted twice with distilled water and crystallized from 5 times the amount of methanol in a mixer.
After washing the crystallized polymer with methanol, it was dried at 60° C. in a vacuum dryer until the loss on drying was 2% or less to obtain a white powdery polymer. The situation of the reaction solution and the isolated yield at each monomer ratio are shown.

[Table] Example 2 Experiment No. 1 of the polymer synthesized in Example 1
~ 4 is 4g, experiment No. 5 is equivalent to 4g of reaction solution,
Stir and dissolve in 450ml of water and add with sodium hydrogen carbonate.
Adjust pH to 7.0. Next, 100 g of commercially available silica gel for thin layer chromatography is added to the viscous aqueous polymer solution and mixed uniformly to form a silica gel suspension that can be easily applied. The above suspension was applied to 20 glass plates of 20 x 20 cm using a sprayer with a gap of 600 μm. This was air-dried for one day at room temperature and then activated at 110°C for one hour. This plate had a uniform surface, no cracks, and had sufficient strength to withstand mechanical pressure. In addition,
The thickness of this thin layer was 220 μm. The properties of the silica gel plate in each experiment number are shown.

[Table] Test method (1) Water resistance test Wako Gel B-Tester (Indophenol, Sudanled G, Butter Yellow): Developed with benzene for 10 minutes, and after sufficiently volatilizing the benzene, left in a desiccator adjusted to a relative humidity of 60%. Then, the degree of spread of butter yellow spots over time was measured. (A plate without a binder was used as a blank.) (2) Affinity test of the plate with water Water was sprayed onto the surface of the prepared plate using a sprayer, and the degree of water penetration into the plate was compared. From the results of Examples 1 and 2, the optimal monomer ratio of the acrylamide-ethyl acrylate copolymer, which has excellent water resistance and affinity with water, and does not affect the adsorbent, is approximately acrylamide. 85 parts and 15 parts of ethyl acrylate to 70 parts of acrylamide and 30 parts of ethyl acrylate
It can be seen that it is within the range of . Example 3 Manufacture of binder 1 A four-necked flask was equipped with a stirrer and a _N2 gas inlet tube, and 200 ml of degassed distilled water, acrylamide monomer and methyl methacrylate monomer were added in the proportions shown in the table below, with a monomer concentration of 10%. Prepare it so that it becomes. Additionally, 4 mg of V-56 as an initiator
(0.02% vs. monomer amount) and N ₂ at 5-10 °C.
Introduce gas for 10 minutes. Thereafter, the internal temperature was adjusted to 45° C., and the reaction was carried out for 5 hours under a N ₂ gas stream. After the reaction, the reaction solution was diluted 4 times with distilled water and crystallized from 5 times the amount of methanol in a mixer. The following treatment was carried out in the same manner as in Example 1. The situation of the reaction solution and the isolated yield at each monomer ratio are shown.

[Table] Example 4 Experiment No. 6 of the polymer synthesized in Example 3
〜9 is 3g, experiment No. 10 is 3g equivalent of reaction solution with water.
Stir and dissolve in 430ml. Example 2 below using 100 g of commercially available silica gel for thin layer chromatography.
Operate in the same manner as 20 x 20 cm silica gel plates.
I got a piece. The thickness of the thin layer was 230 μm. The properties of the silica gel plate in each experiment number are shown.

[Table] Test method Same as Example 2 From the results of Examples 3 and 4, the optimum monomer ratio of the acrylamide-methyl methacrylate copolymer as a binder that meets the purpose of the present invention is approximately 90 parts of methyl methacrylate to 80 parts of acrylamide and 20 parts of methyl methacrylate. Example 5 4 g of the polymer synthesized according to the recipe of Experiment No. 3 of Example 1 was stirred and dissolved in 260 ml of water, and the pH was adjusted to 7.0 with sodium hydrogen carbonate. Add 60% of commercially available silica gel (particle size 5 to 15 μm) to this polymer aqueous solution.
g and 1.2 g of Aerosil were mixed in a ball mill for 1.5 hours to prepare a uniform silica gel suspension.
Adjust the gap of the automatic coating machine to 550μm and apply 20×
Apply to 10 20cm glass plates. It was dried and activated according to a conventional method. The thin layer thickness of this plate is
It was 250 μm. The surface of this plate was excellent in smoothness, had high impact abrasion resistance, and had a writing hardness (the lowest hardness at which scratches occur when making pencil marks on the plate surface) of H or higher. B-Tester: Deployability and Rf during benzene development
Show value.

[Table] Example 6 2 g of the polymer synthesized according to the recipe of Experiment No. 8 of Example 3 was dissolved in 180 ml of water, and the pH was adjusted to 7.0 with sodium hydroxide. In this polymer aqueous solution,
Add 60 g of commercially available silica gel (particle size 5 to 15 μm), 10 ml of Snowtex, and 6 g of mixed phosphor,
The following treatment was carried out in the same manner as in Example 5. The thickness of the thin layer of this plate was 250 μm. This plate had excellent surface smoothness, high impact abrasion resistance, and a pencil hardness of 2H or higher. Shows the developability and Rf value when standard products of brucine, procaine, dibucaine, narcotine, and caffein are developed with a mixed solvent of 70 parts of methanol, 20 parts of benzene, 5 parts of acetic acid, and 5 parts of acetone.

[Table] Example 7 Dissolve 2 g of the polymer synthesized according to the recipe in Experiment No. 8 of Example 3 in 230 ml of water, and adjust the pH to 8.0 with sodium hydrogen carbonate. 60 g of commercially available basic aluminum for thin layer chromatography and 10 ml of alumina sol were added to this polymer aqueous solution and mixed.
Prepare a uniform coating suspension. Set the gap between the coating machine to 450μm and apply to 10 20x20cm glass plates. After drying at room temperature for 1 day, it was activated at 140-150°C for 1 hour. The surface of the layer thus obtained was homogeneous, free of cracks, had excellent impact abrasion resistance, and had a pencil hardness of H or higher. Note that the thickness of this thin layer was 200 μm. Example 8 The detection resistance reagent test results of the plate manufactured in Example 6 are shown.

【table】

[Table] As shown in the above results, it is stable against detection reagents and the spots are clearly and easily identified.

Claims (1)

[Claims] 1. 99 to 90 parts by weight of an adsorbent selected from silica gel, diatomaceous earth, aluminum oxide, magnesium silicate, calcium phosphate, cellulose, polyamide, and polycarbonate, and the general formula (However, R ¹ represents H or CH ₃ and R ² represents CH ₃ or C ₂ H _5. ) A combination of acrylamide and acrylic ester or acrylamide and methacrylic ester An adsorption material for chromatography whose main composition is a mixture comprising 1 to 10 parts by weight of at least one type of binder selected from polymers.