JP2003166983A - Method of manufacturing solid-phase extraction adsorption column - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method, by which a solid-phase extraction adsorption column that is inexpensive than a column using granular filler and a molded container and is suitable for the detection of trace elements can be manufactured. <P>SOLUTION: The adsorption column is manufactured, by putting a small piece of a double-pored porous material in a heat-shrinkable tube, having a longer length than the piece has and heat-shrinking the tube. The porous material is composed of silica, containing through-holes having diameters of >500 nm and continuously formed in a three-dimensional net-like state and micropores, having pore diameters in the range of 5-20 nm and formed in the internal wall surfaces of the through-holes or silica having a chemically modified surface. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a solid-phase extraction method in which a sample is injected into a column to be sorbed by a sorbent in the column, and then components in the sample are extracted with an appropriate solvent for analysis. The present invention relates to a method for producing a sorption column used in. Often, the sample is injected into the column using a syringe.

[0002]

2. Description of the Related Art As a sorption column used in such applications, generally, a plastic container having an injection port having a pore size capable of being connected to a syringe is packed with a particulate packing material such as silica gel or octadecyl silica gel. It is used.

The sorption column is usually disposable, but when a particulate filler is used, a preformed container is required for filling, so a container charge is required for disposable use. Has the drawback of being expensive.

[0006] Furthermore, if the particulate filler is not carefully filled, a channeling phenomenon occurs in which the extraction solvent and the like pass through a large passage caused by the filling unevenness, so that there is a problem that the filling takes time.

Further, as the particulate filler, one having a particle diameter of about 40 μm (= 0.04 mm) which is easy to fill is generally used. The filler having such a large particle size is
Since the specific surface area is smaller than that of the filler having a small particle size of 10 μm (= 0.01 mm) or less, the maximum sorbable amount (retention capacity) of the filler per unit weight is also small.
Therefore, a packing material with a large particle size must be used in a larger amount than a packing material with a small particle size in order to ensure a certain maximum sorption amount (total retention capacity) as a column necessary for use. . As a result, the amount of solvent required for extraction increases, so that in the case of detecting a trace component contained in a sample, concentration is required after extraction and before analysis, which is inefficient. Thus, a filler having a large particle size is easier to fill than a filler having a small particle size, but there is a problem in that the retention capacity is related.

In order to solve the problem of storage capacity, for example, a disc in which 10 μm (0.01 mm) silica gel was wrapped in a sandwich shape with a polyethylene screen and a glass fiber filter was prepared and set in a molding container. Sorption columns for solid-phase extraction have been developed, but they are troublesome to manufacture, and there is a cost problem in using a molded container.

[0007]

In consideration of the fact that the sorption column for solid phase extraction is used in a disposable state, it is necessary to reduce the labor required for production and the cost for the container.

Further, in order to detect a trace component efficiently, it is necessary to use a filler having a large holding capacity to reduce the filling amount. An object of the present invention is to provide a method for producing a sorption column for solid phase extraction, which is cheaper than a column using a particulate filler and a molding container and is also suitable for detecting a trace amount component, in order to solve these two requirements at the same time. Especially.

[0009]

[Means for Solving the Problems] In order to reduce the cost, a cheaper heat-shrinkable tube is used as a container instead of a molded product, but this is not a particulate sorbent, but a sorbent. It becomes possible only by using a monolithic type double-pore porous body which does not require a filter for preventing dispersion. This porous body must of course have a large holding capacity. Further, by changing the size of the porous body, the total holding capacity and the amount of solvent necessary for extraction can be adjusted.

[0010] A small piece of a double-pore porous body of a predetermined size, for example, a cylinder, is placed in a longer heat-shrinkable tube and heated to a temperature at which the tube shrinks. The sorption column for solid phase extraction of the present invention as shown in can be obtained.

As the heat-shrinkable tube, one made of polyethylene, polytetrafluoroethylene, or other plastic can be used. Further, the inner diameter of the heat-shrinkable tube needs to be selected in consideration of the shrinkage ratio so that the hole diameters of the injection ports formed at both ends of the sorption column after the shrinking treatment have a size that can be connected to the syringe.

In order to solve the problem relating to the holding capacity, the particle size used in high performance liquid chromatography is 1
It is desirable to use a double-pore porous body having a specific surface area of 0 μm (0.01 mm) or more, and a through-hole having a pore size of 500 nm or more and continuous through holes in a three-dimensional mesh shape, which is responsible for mass transport. A double-porous silica porous body having 5 to 20 nm fine pores formed on the inner wall surface of the through-hole, which is responsible for sorption, is suitable.

As the double-pore silica porous material having such performance, a porous glass produced by using a phase separation phenomenon caused by heat treatment of borosilicate glass, a porous glass synthesized from a silicon alkoxide by a sol-gel method, etc. There is.

In the former case, when sodium borosilicate is heated to several hundred degrees, it is divided into two phases, a borate phase soluble in acid and a silicon skeleton insoluble in acid, by a phase separation phenomenon. It is prepared by eluting borate.

In the latter case, when a silicon alkoxide is added to an acidic solution of an organic polymer to cause hydrolysis and subsequent polycondensation, the reaction solution gels and is a porous wet gel having three-dimensional network through-holes. It can be prepared by treating this with an alkali to form fine pores on the inner wall surface of the through hole, and then drying and heat treating.

As the silicon alkoxide, tetramethoxysilane, tetraethoxysilane, etc. are preferably used. The organic polymer is preferably an ionic or nonionic water-soluble polymer such as polyacrylic acid or polyethylene glycol, and the alkali is preferably volatile ammonia which can be removed by the drying and heat treatment steps.

The organic polymer can be considerably removed by adding a washing step before the alkali treatment, but finally, it is completely decomposed and removed during the heat treatment.

The particulate packing (silica gel) used in the sorption column for solid-phase extraction has a surface similar to that of silica gel for liquid chromatography, and has a non-polar group such as a phenyl group or an alkyl group or a polar group such as amine or nitrile. Many of them are chemically modified with a group, but the double-porous silica material used in the present invention can also be chemically modified by the same method as that of the particulate silica gel.

[0019]

EXAMPLES Example 1 10.2 g of polyethylene glycol (molecular weight 10,000) was dissolved in 100 ml of 0.01N acetic acid, and 45 ml of tetramethoxysilane was added thereto, and the mixture was mixed at 40 ° C. for 3 hours.
The reaction was allowed for 0 minutes. The required amount of reaction liquid is 8 mm in inner diameter and 8 in height
It was placed in a cylindrical polypropylene mold of mm and held in a drier at 40 ° C., whereupon it became cloudy and solidified in several hours. The solidified sample was further aged in a dryer for one day, then taken out from the mold and washed with distilled water. Then 0.01 at 40 ℃
After being immersed in a specified aqueous ammonia solution for 3 days, dried at 50 ° C. and heat-treated at 600 ° C. for 2 hours, a through-hole having an average of about 1.7 μm (= 0.017 mm), a fine hole having an average of about 13 nm and an average of about 370 m ² A cylindrical double-porous silica porous body having a specific surface area of / g and a diameter of 6 mm and a height of 4 mm was obtained.

Next, the columnar porous body was made to have an inner diameter of 8.5 m.
A sorbent column for solid phase extraction of the present invention was produced by placing the tube in a heat-shrinkable polyethylene tube (made by Sumitomo Electric Industries, Ltd.) having a length of m and a length of 40 mm and heat-treating at 100 ° C. for 10 minutes.

Example 2 The silica porous material prepared by the method of Example 1 was reacted with octadecyltrichlorethylene in refluxing toluene for 16 hours in accordance with a usual method to chemically modify the surface with octadecyl group, and then the reversed phase recovery was performed. 40 mg of a cylindrical double-porous silica porous material as a binder was obtained. Then, using this, a sorption column for solid phase extraction was manufactured in the same manner as in Example 1.

The total retention capacity of this column was about 10% of the sorbent weight. In addition, column performance tests were performed using a sample prepared by adding known concentrations of primidone, phenobarbital, carbamazepine and phenytoin to distilled water, conditioning the column, injecting the sample into the column, washing,
The samples were processed in the order of extraction, and the extracts were analyzed by high performance liquid chromatography. 400 μl of methanol and distilled water were used for conditioning the column. A sample injection amount was 500 μl, and 600 μl of distilled water was used for washing. Next, as a result of examining the amount of solvent (methanol) required for extraction, it was possible to completely extract with 500 μl (recovery rate 100%). In addition, using the same amount of sample, 100 m of particle filler having a particle diameter of 40 μm (0.04 mm)
When the performance was compared with the conventional column filled with g, the conventional column was found to have 2.0% as a conditioning solvent.
1.5 ml of methanol and distilled water as washing solvent
1 of distilled water and 2.0 ml of methanol as extraction solvent were required.

[0023]

As described above, according to the present invention, it is possible to easily manufacture a sorption column for solid-phase extraction, which is cheaper than a column using a particulate filler and a molding container and which is also suitable for detecting a trace component. You can This column can be used by connecting to a syringe, and the column is extremely suitable in terms of price and performance for this type of analysis, which is generally accepted as disposable.

[Brief description of drawings]

FIG. 1 is a plan view of a sorption column for solid phase extraction of the present invention.

FIG. 2 is a side view of the sorption column for solid phase extraction of the present invention.

[Explanation of symbols]

1 Double porous silica 2 polyethylene tube 3 Polyethylene tube (portion that becomes the inlet)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G01N 30/56 G01N 30/56 A // G01N 30/06 30/06 Z F term (reference) 4D017 CA05 CB01 DA03 4G066 AA22A AA22B BA23 DA07 EA01

Claims (2)

[Claims] 1. A through-hole having a hole diameter of 500 nm or more and continuous in a three-dimensional mesh, and a hole diameter of 5 to 5 formed on the inner wall surface of the through-hole.
A sorption column for solid-phase extraction, characterized in that a small piece of a double-pore porous body made of silica having fine pores of 20 nm is placed in a heat-shrinkable tube longer than that and then heat-shrinked. Production method. 2. The method for producing a sorption column for solid phase extraction according to claim 1, wherein the double-porous material is silica whose surface is chemically modified.