JPH037905B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a column for liquid chromatography.

[Conventional technology]

To achieve high separation efficiency in liquid chromatography, metal columns (tubes) filled with sorbent particles are used. During a chromatographic process, solvent flows through a column, usually under considerable pressure. The most commonly used material for the manufacture of columns is stainless steel, which gives the column good mechanical properties and sufficient pressure resistance,
In most cases, the material is sufficiently resistant to corrosion that can be caused by the liquid applied as a mobile phase or by the analyte compound. The column is then sealed with a metal or suitable plastic gasket. The seals must be designed to minimize dead volumes at the inlet and outlet of the column and to prevent unwanted spreading of the sample by flowing liquids during the chromatographic process.

[Problem to be solved by the invention]

Although a number of seals have been designed for the aforementioned purposes that meet the aforementioned requirements, they suffer from some of the negative effects of liquid chromatography inherently due to the concepts and materials traditionally used. It shows.

First of all, the use of metal columns is limited by the corrosion resistance of the material itself (stainless steel). For example, stainless steel exhibits very good corrosion resistance to most organic solvents;
When brought into contact with organic acids, halogenated hydrocarbons, and their decomposition products for long periods of time, their corrosion resistance is insufficient. Metal columns are also substantially resistant to the action of aqueous acids and salts commonly used in reversed-phase chromatography, ion-exchange chromatography, and biopolymer affinity and gel chromatography. It can not be said. Furthermore, they are still often separated by liquid chromatography,
Irreversible changes in the sample may occur due to contact of the sensitive biologically active mixture with the metal.

Since most common column designs are relatively complex, the issue of precise machining of metallic materials is equally important. A highly polished inner surface of the tube is a prerequisite for satisfactory packing and use of the column. For these things,
The manufacturing cost of metal columns is relatively high. In most cases, common designs serve a single purpose and have a limited lifespan. If the chromatographic system is changed or its efficiency decreases, the entire column must be replaced.

Design principles similar to those for metal columns were also used in the manufacture of glass columns (see, for example, Tiekoslovakia Patent No. 183,468). Glass columns have numerous advantages in liquid chromatography. Their main advantage is that they have high chemical resistance to the action of aggressive mobile phases or separation compounds. Also, with glass columns, the inner surface of the tube can be easily made to a high degree of precision, thereby minimizing zone broadening caused by roughness of the tube inner surface, which is equally important. . However, glass has low pressure resistance and is quite brittle, and the glass column must be shaped to attach a sealant, so it is difficult to use a glass column with this known configuration for high performance liquid chromatography. It was. Designs that use metal jackets to supplement column internal pressure with external pressure are needed but are expensive.

Therefore, an object of the present invention is to solve the problems of the conventional liquid chromatography columns described above.

[Means to solve the problem]

According to the invention: (i) a glass tube for filling the sorbent; (ii) a jacket surrounding said glass tube and having connecting means at each end; (iii) located at each end of said glass tube. a bushing having an opening spaced between the glass tube and the jacket and joined to the outer end of the glass tube; (iv) disposed in the opening of each bushing; a seal each covering an opening at each end of said glass tube and having an opening having a size larger than said tube opening and being obstructed by a permeable septum element; and (v) said jacket. a socket including an element connected to the connecting means at each end of the socket and having a surface in contact with the corresponding seal, the element cooperating with the corresponding connecting means to exert a compressive pressure on the corresponding seal and A liquid chromatography column is provided comprising a removable socket having a liquid communication opening leading through a transparent partition element and into the interior of the glass tube.

The seal may be suitably disposed on the bushing supporting the glass tube within the jacket and may be inserted between the inner wall of the jacket and the outer wall of the glass tube. The bushing can be adhesively bonded to the glass column, and a gasket-containing seal having a permeable partition in its recess can be inserted into the opening of the bushing. The joining between the metal bushing and the glass tube is preferably carried out by a low melting point alloy with a melting point of 60 to 250° C., consisting of an element selected from the group of bismuth, lead, tin, cadmium, zinc and antimony. You can also do that.

Another possible form of a liquid chromatography column consists of a bushing made of metal with radial grooves provided in its inner wall. The bushing has a plastic insert with a step on the outside that fits into a groove in the bushing. The insert, on the other hand, has a permeable septum inserted into the bottom that supports the surface of the glass tube.

Since the jacket does not come into contact with the mobile phase,
Metals with low corrosion resistance, such as aluminum, brass,
or plastic materials such as polyamide, polypropylene, poly(vinyl chloride), polyester resins, phenol-formaldehyde and urea-
It can also be made from plastic materials selected from the group of formaldehyde resins. Sockets can also be made from these materials and can be lined with a corrosion-resistant part of materials such as stainless steel or glass. The walls of the jacket can be porous to allow visual observation of the chromatographic process and filling.

The column according to the invention does not use a continuous capillary which increases the zone spread.
They can be connected in series in a simple way. Stiffness is achieved by the pressure exerted by the socket on the seal of the glass tube.

The column according to the invention also eliminates the recent drawbacks of glass columns mentioned above. The relatively brittle glass tube is placed in a strong protective jacket during operation, and the low pressure resistance of the glass can be chemically strengthened, for example by the process described in Tiekoslovakia Inventor Certificate No. 183468. Can be done. The ends of the glass tube then do not need to be expanded because the axial pressure generated during column operation is transferred by the gasket on the metal jacket and the glass column seals are not stressed.

Glass tubes can advantageously be reinforced with a surface phase of potassium ions obtained by diffusion of potassium ions into the glass at high temperatures. This finish increases the resistance of the glass tube to the effects of pressure during sorbent filling and during high performance liquid chromatography.

Besides the high chemical resistance of the glass and the perfect internal surface of the tube, another great advantage is that it is possible to visually observe the chromatographic separation and the packing condition through one or several sight holes in the jacket. It is. Glass tubes filled with various sorbents are replaced in a single jacket by a simple operation without the use of special tools, in the same way as is required for different types of chromatographic analysis. be able to. This tube replacement possibility is
Provides substantial cost savings for a set of columns packed with various sorbents. To replace the original column with a new column, you only need to bring the inner glass tube filled with the necessary sorbent. Connecting columns in series can easily form various combinations on the principle of a building-block system by incorporating short protective spare columns.

The column according to the invention offers a more economically advantageous solution not only for the user but also for the manufacturer. Many machining operations are eliminated in the fabrication of each single column, reducing labor intensity and metal material costs. The design of the column according to the invention substantially increases the rate of mechanization and automated operations in its fabrication and sorbent loading.

The accompanying drawings schematically show, in cross-section, several designs of columns according to the invention and their most important parts.

In FIG. 1, the column consists of a glass tube 1 for filling the sorbent, placed in a jacket 4 having a thread 6 at its outer end. This glass tube 1 is provided with seals at both ends thereof. This seal consists of a permeable septum 3 and a gasket 7 located on the septum and provided with an opening 8.
This gasket 7 is inserted into a bush 10. The bushing 10 is joined to the outer end of the glass tube 1 by an adhesive insert 15, thereby defining the lateral position of the glass tube 1 relative to the jacket 4. In the longitudinal direction, the glass tube is fixed in the jacket 4 by a socket 5. The face 2 bearing the gasket 7 thereon is screwed into the socket 5. Channel 11 is coaxial with opening 8 in gasket 7. The socket 5 has a thread 16 on its inner wall for connection with the jacket 4. Column jacket 4 is
It can be made from metals such as brass, stainless steel, or plastics such as poly(vinyl chloride), polypropylene, polyester or polyamide. Sight holes can be provided in the jacket wall for visual observation of the chromatographic process. Gasket 7 is made of plastic material, preferably polytetrafluoroethylene. The permeable barrier 3 is made as a porous plate from stainless steel, polytetrafluoroethylene or glass, or as a metal mesh. The bushing 10 has an outer diameter such that the jacket 4 slides therethrough. After screwing the socket 5 into the jacket 4, the face 2 of the socket 5 fits into the gasket 7 and the column is ready for use. The bonding insert 15 is produced by filling the space between the outer surface of the glass tube 1 and the inner surface of the bush 10 with a molten low-melting metal alloy heated to a temperature between 0.5 and 150° C. above its melting point. can be administered. For example, alloys of bismuth, lead, tin, cadmium, zinc and antimony having melting points in the range from 60 to 250°C can be suitably used. This alloy bonds very strongly to the glass tube because it shrinks during solidification and the metal fitting also closes on cooling. In this case, the radial stress, which is probably pre-existing in the glass, acts favorably against the radial pressure acting in the opposite direction during the chromatographic process;
and strengthen the most stressed end of the column. In order to fit the bushing 10 into the glass tube 1, a center pin made of polytetrafluoroethylene can be advantageously used, which ensures the correct geometry of the column ends and the low melting point As long as the alloy is liquid, the positions of the glass tube 1 and the bush 10 are fixed, which simplifies the overall operation.

The seal of the glass tube 1 is as shown in FIG.
It can also be arranged in a metal cylindrical bushing 10 having a shaped inner wall with grooves 17.
The bush 10 is filled with a plastic insert 12, such as polytetrafluoroethylene, having a conical taper 13. The inner diameter of the cylindrical part of the insert 12 is smaller than the outer diameter of the glass tube 1, and a porous septum 3 is arranged inside the insert 12.
After pressing the glass tube 1 into the bush 10, the recess of the bush 10 is filled with plastic material and the tube is fixed by the tension created.

Another form of seal for tube 1 is shown in FIG. This seal is formed by a plastic plug 9 with a drilled hole 14. This plug fixes the porous septum 3 and is fitted by its enlarged end into the step 18 of the bush 10. The mechanism for sliding the glass tube 1 into the jacket 4 with a seal and its fixing mechanism are
The same is true for adhesive bonding to a tube of 0.

Individual columns with jackets can be connected in series as shown in FIG. The face 2a is supported on both sides in the gaskets 7 of the seals of both connected columns. The column is connected using threads 16 for screwing onto the jackets 4, 4a.
It is fixed by two-striped sockets 5a provided on both sides.

If the temperature of the glass tube 1 is to be controlled by a thermostatic medium, the glass tube 1 can be sealed against the jacket 4 and provided with inlet and outlet openings for the attachment of thermostatic medium piping. can be provided. Sealing can be accomplished by an O-ring placed in a groove in the outer wall of the bush 10.

Furthermore, the jacket 4 can be provided with one or several sight holes with or without a glass cover for visual observation of the column filling.

In order to explain the invention in more detail, examples of chromatographic columns according to the invention are described below.

The column was manufactured according to FIG. glass tube 1
was made of boron silicate glass under the trade name SIAL, with an inner diameter of 3 mm and a wall thickness of 2.5 mm. The glass tube was 100 mm long. A seal 2 manufactured according to FIG. 1 was adhesively bonded to the tube 1, and the porous septum 3 was made of stainless steel mesh with a diameter of 3 μm and secured with a polytetrafluoroethylene gasket 7. . The outer jacket 4 has an inner diameter
It was made of brass tube with a diameter of 12 mm and a wall thickness of 2.5 mm, and had two sight holes cut in the longitudinal direction in opposite directions. Both ends of the jacket 4 are provided with threads 16 into which a brass socket 5 is fitted, together with a stainless steel face 2 with an opening and an external thread for mounting the connecting capillary.
was screwed. The column was packed with spherical silica gel microparticles with a particle size of 5 μm at a pressure of 40 MPa, and an efficiency of 25,000 theoretical plates per meter of column length was obtained. As a result of a pressure test on an empty column, the glass tube 1 treated by surface diffusion of potassium ions was able to withstand a pressure of 80 MPa without breaking.

The bush 10 was fixed to the glass tube 1 in the following manner. Internal recess 1 with a diameter of 6.5 mm and a height of 2 mm
8, a stainless steel bushing with an outer diameter of 10 mm, an inner diameter of 9 mm and a length of 8 mm, with a diameter of 3.5 mm and
A 6.5 mm step-machined polytetrafluoroethylene central pin was first placed. 50% bismuth,
Approximately 0.7 g of an alloy consisting of 25% lead, 14.5% tin and 12.5% cadmium (melting point 60.6°C) was inserted into the recess of the bush. This assembly, together with the ends of the glass tube 1 with an inner diameter of 3.3 mm and an outer diameter of 8.3 mm, is heated to 90° C. by hot air, and then the glass tube 1 is immediately placed in a stainless steel bushing 10. It was slid and centered with a pin. The displaced excess alloy was removed while still in a liquid state, and after solidification it was completely cut with a knife and the central pin was extracted. Stainless steel bushing 1
0 could not be removed from the glass tube 1 even with pliers. The composition of the alloy depends on the melting point chosen and, for example, VJ
Perelman: Small Chemical Handbook (translated from Russian to Chieko, 1945), page 473. An alloy composition corresponding to a melting point in the range of 60 to 250°C consists of the following amounts of each element.

Bismuth 0-70% Lead 0-90% Tin 0-100% Cadmium 0-50% Zinc 0-15% Antimony 0-15%

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a column assembly with a jacket in accordance with the present invention. FIG. 2 is a sectional view showing another example of a column seal. FIG. 3 is a sectional view showing yet another example of a column seal. FIG. 4 is a sectional view showing an example of a seal and socket for connecting columns in series. DESCRIPTION OF SYMBOLS 1... Glass tube, 2... Face, 3... Permeable partition, 4... Jacket, 5... Socket, 6
...Screw thread, 7...Gasket, 8...Opening,
9...Plug, 10...Butsuyu.

Claims (1)

[Scope of Claims] 1 (i) a glass tube for filling a sorbent; (ii) a jacket provided with a connecting means at each end and surrounding said glass tube; (iii) located at each end of said glass tube; a bushing having an opening and joined to the outer end of the glass tube, the bushing being spaced between the glass tube and the jacket; (iv) a bushing disposed in the opening of each bushing; , a seal having an opening respectively covering an opening at each end of said glass tube, having an opening having a size larger than said tube opening and being obstructed by a permeable septum element; and (v) said glass tube. A socket connected to the connecting means at each end of the jacket and including an element having a surface in contact with the corresponding seal, the element cooperating with the corresponding connecting means to exert a compressive pressure on the corresponding seal, and A column for liquid chromatography comprising a removable socket having a liquid communication opening leading into the interior of the glass tube through a permeable partition element. 2. The column according to claim 1, wherein the glass tube is reinforced by surface diffusion of ions. 3. The bushing is adhesively bonded to the outer end of the glass tube by means of cement and has a seal consisting of a gasket with a recess in its opening and a permeable septum disposed within the recess. Columns listed in section. 4. The bush is made of metal, has a radial groove provided in its inner wall and is provided with a plastic insert inside, said insert bearing bottom in the face of the glass tube and having an insert. 2. A column as claimed in claim 1, comprising a permeable septum. 5. The bushing is supported on the surface of the glass tube and has a step provided in its opening, and the plug is fitted with a permeable septum inserted into said opening. The column described in Section 1. 6. The jacket is made of a metal selected from the group of stainless steel, aluminum and its alloys, brass and titanium, or selected from the group of polyamide, polypropylene, poly(vinyl chloride), polyester resin, phenol-formaldehyde resin and urea-formaldehyde resin. Column according to claim 1, which is made of plastic. 7. A column according to claim 1, wherein the face is remote from the socket and has two threads at each end thereof for connection to the jacket of another column. 8. A column according to claim 1, wherein the jacket is provided with openings for the inlet and outlet of the thermostatic medium. 9. A column according to claim 1, wherein the column jacket is provided with one or several sight holes for visual inspection of the column packing. 10 A patent in which the bush is fixed to a glass tube by an alloy consisting of an element selected from the group of bismuth, lead, tin, cadmium, zinc, and antimony, and whose melting point is 60 to 250°C. A column according to claim 2.