JPH0410377B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to an adsorbent having a surface modification layer. [Prior Art] Conventionally, adsorbents such as silica gel whose surfaces are chemically modified are known. Among these, silica gel whose surface is modified with an alkylsilyl group, phenylsilyl group, etc. is well known and is widely used as a column packing material for high performance liquid chromatography. However, conventional surface-modified adsorbents are insufficient to selectively adsorb a specific solute from among multiple solutes with similar physicochemical properties. It is extremely difficult to efficiently selectively adsorb only
This is due to the fact that the modification layer on the adsorbent surface is not sufficiently dense and its orientation is small. [Objective] The present invention aims to overcome the above-mentioned drawbacks found in conventional surface-modified adsorbents. [Structure] According to the present invention, on the surface of an adsorbent on which a surface treatment agent having an ionic functional group is bonded in advance, an ionic hydrophilic agent charged oppositely to the ionic functional group of the surface treatment agent is added. Provided is an adsorbent having a surface modification layer made of a lipid, which is characterized by adhesively bonding a lipid having a group thereto. The lipids used in the surface modification layer of the adsorbent in the present invention are:
It contains both hydrophobic groups and hydrophilic groups and is generally water-insoluble, and conventionally known natural or synthetic lipids are used. In this case, examples of hydrophilic groups include anionic groups such as carboxyl groups, sulfonic acid groups, sulfuric acid ester groups, and phosphoric acid groups, and cationic groups such as ammonium groups and organic ammonium groups.
Examples of the hydrophobic group include steroid skeleton structural groups such as sterine and cholesterol, and aliphatic groups having two or more alkyl groups or fluoroalkyl groups having 8 or more carbon atoms. If it contains a steroid skeleton or the like, one hydrophobic group may be sufficient. Particularly suitable lipids for use in the present invention are those that form an association such as a bilayer membrane structure in water. Specific examples of the lipids used in the present invention include those shown in Examples below, as well as the following. (1) [H ₃ C (CH ₂ ) ₁₃ ] ₂ N+ (CH ₃ ) ₂・Br ^- (2) [H ₃ C (CH ₂ ) ₁₁ O] ₂ PO ₂ ^- Na ⁺ [F ₃ C (CF ₂ ) ₇ (CH ₂ ) ₂ COO (CH ₂ ) ₂ ] ₂ NCOCH ₂ N ⁺ (CH ₃ ) ₃ ·Br ^- ion A suspension of an adsorbent carrier covered with a functional group is mixed with a natural or synthetic resinous dispersion having an ionic hydrophilic group with an opposite charge to the ionic functional group, and the mixture is heated or sonicated. do it. In this case, organic or inorganic granular powder is used as the adsorbent carrier, and examples thereof include silica gel, alumina, magnesia, various clay minerals, activated carbon, carbon fiber, and resin particles. In addition, the ionic functional groups coated on the surface of these adsorbent carriers include anionic groups such as carboxyl groups, sulfonic acid groups, sulfuric acid ester groups, and phosphoric acid groups, and cationic groups such as ammonium groups and organic ammonium groups. Examples include ionic groups. The adsorbent carrier can be coated with these ionic groups by, for example, treating the surface with a surface treatment agent such as a silane coupling agent according to a conventionally known method, and then applying this surface treatment agent to obtain the desired ionic groups. The adsorbent carrier may be surface-treated by reacting the reaction reagent as described above, or by using a surface-treating agent having an ionic group. [Effects] The surface modification layer of the adsorbent of the present invention is made of lipid, and due to the properties of the lipid, it is characterized by superior density and high orientation compared to conventional modification layers. have. Therefore, when using the adsorbent of the present invention, a specific component can be selectively adsorbed from a mixture of similar physicochemical properties, such as a mixture of structural isomers, due to the specificity of the modified layer. The adsorbent of the present invention can be advantageously used as a stationary phase for high-speed fluid chromatography, and can be applied to mixtures for which conventional reversed-phase chromatography has been unable or insufficient to separate peaks, such as xylene, dichlorobenzene, methyl It is possible to perform qualitative and quantitative analysis of structural isomer mixtures such as naphthalene. Moreover, the adsorbent of the present invention can also be used as a packing material for separation and purification columns. [Example] Next, the present invention will be explained in more detail with reference to Examples. Example 1 0.8 g of porous silica gel with a particle size of 5 to 20 μm, (3
-Mercaptopropyl)trimethoxysilane 1.6
After heating a mixture of g and 10 ml of methanol for about 24 hours, silica gel was filtered from the resulting mixture,
It was further heated at 100°C for 1 hour. This silica gel was treated with a mixture of 10 ml of 5% sodium bicarbonate solution and 2 ml of sodium hypochlorite solution to convert the mercapto groups of (3-mercaptopropyl)trimethoxysilane bonded to the silica gel surface into sulfonic acid groups. Ta. After heat-treating the silica gel coated with sulfonic acid groups at 50 to 70°C in a dispersion of a lipid represented by the following structural formula (), the silica gel is filtered from the resulting reaction product and washed with water. The adsorbent of the present invention was obtained. Next, the adsorbent obtained above was packed into a column for liquid chromatography, and the selective adsorption of keratosolutes was determined by the separation coefficient α
(Ratio of retention time of keratin solute). The following table shows the separation coefficient α in relation to the solute. The eluent used was a methanol/water mixture (mixing ratio =
90/10 to 40/60 was used.

[Table] Example 2 The silica gel carrier whose surface was coated with sulfonic acid groups shown in Example 1 was heat-treated in a dispersion of a lipid represented by the following structural formula () to obtain an adsorbent of the present invention. (H ₃ C) ₂ N ⁺ [(CH ₂ ) ₁₇ CH ₃ ] ₂ ·Br ^- () Next, the selective adsorption of solutes on this adsorbent was investigated in the same manner as in Example 1. The results are shown in the table below.

[Table] Example 3 An adsorbent was produced in the same manner as in Example 2, except that a lipid represented by the following structural formula () was used, and the selective solute adsorption of the adsorbent was made in the same manner as in Example 1. I looked it up. The results are shown in Table-3.

【table】

Claims (1)

[Claims] 1. A lipid having an ionic hydrophilic group that is oppositely charged to the ionic functional group of the surface treating agent is adhesively bonded to the surface of an adsorbent on which a surface treating agent having an ionic functional group has been bonded in advance. An adsorbent having a surface modification layer made of lipid.