CH654218A5 - DEVICE FOR LINEAR ON PRESSURE layer chromatography. - Google Patents

Description

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PATENT CLAIM Device for linear overpressure layer chromatography with a base plate (2) carrying the sorbent layer (1), characterized in that it has a cover plate (5) which can be fixed to the base plate (2) and which is elastic from above with a sorbent layer (1) closing membrane (4) is provided, a valve (11) for introducing a pressure medium between the membrane (4) and the cover plate (5) and, sealed through the cover plate (5) and the membrane (4), at least one inlet element ( 6) for the eluent and at least one sample application member (7).

The invention relates to a device for linear positive pressure layer chromatography with a base plate carrying the sorbent layer. The device can be used on a sealed, pneumatically, hydraulically or otherwise pressurized, sealed sorbent layer at an adjustable temperature over any length and width in one or two directions, dry or wet, isocratic or gradient, in one or two Dimensions and also chromatographed in the so-called overflow technique.

Overpressure layer chromatography is a liquid-time chromatography technique on closed, flat surfaces. The sorbent layer is completely sealed off by a plate which is pressurized from the outside, and the solvent is kept in a forced flow between the particles of the sorbent by means of a suitable metering device (Hungarian Patent No. 173 749). This latest form of liquid chromatography on surfaces has several advantages compared to classic layer chromatography: the runtime is shorter, the resolution is better, less solvent is required; the development with viscous solvent mixtures can be accelerated, the process can be visually monitored, the use of aggressive reagents is possible, etc. In addition, the upper pressure layer chromatography has all the advantages of high pressure column chromatography.

So far, only the circular pressure chamber is known for overpressure layer chromatography (E. Tyihäk, E. Mincsovics and H. Kalâsz: J. Chromatogr. 174,75 / 1979 /). On one, the lower plate of the device made of plexiglass, there is the commercially available or spread sorbent layer with maximum dimensions of 200 x 200 mm. The plexiglass cover plate lies on this, in which the following components are installed: a) a pressure gauge, b) a pressurized sample dosing device, c) a gas inlet opening, d) an O-ring for enclosing the plastic film, e) one Plastic membrane, f) an opening for introducing the solvent, provided with elastic, spiral-shaped metal lines. The cover plate is fastened accordingly and the cushion is inflated with nitrogen, for example.

It is characteristic of all previously known variations of layer chromatography that the path covered by the solvent (z in cm) and the time required for this (t in sec) are related according to the 2nd degree equation. The speed constant is designated by k. This applies to both the circular disc variant and the linear variant of the so-called HPTLC technology (R.E. Kaiser: Introduction to high-performance thin-layer

matographie, Institute for Chromatography, Bad Dürkheim, 1976) as well as for the circular disc device of over-pressure layer chromatography (Tyihäk et al .: J. Chromatogr. 174,75 / 1979 /). In the latter case, a constant solvent velocity cannot be maintained along the circle radius for reasons of principle alone.

In the linear variant of overpressure layer chromatography, the prerequisite for a good layer chromatogram, namely the constant flow rate of the solvent or the linear solvent front, can only be achieved by using layers closed at the edges and introducing the solvent by means of a wire placed in front of the entry point of the solvent or platelets or through a groove carved into the sorbent layer.

In linear overpressure layer chromatography, there is therefore a linear relationship between the path covered by the solvent (z in cm) and the time required for this (t in sec):

where k is a rate constant, i.e. Overpressure layer chromatography offers ratios like column chromatography, which means a qualitatively new chromatographic technique. Of the two possible variants of overpressure layer chromatography, namely circular and linear, the development of the latter is of priority, since a technical advance towards more effective separation can be expected there.

Special sorbent plates and a device in the form of a chamber are required for linear overpressure layer chromatography.

A device developed in accordance with Hungarian Patent No. 173 749 is only suitable for chromatography over relatively short distances, although it can be seen from the first degree context above that the flow rate of the solvent remains constant even at a greater distance. Since the theoretical number of trays or the number of separations introduced by Kaiser / Kaiser (Editor) in the book "Introduction to high-performance thin-layer chromatography" (Institute for Chromatography, Bad Dürkheim, 1976) increases proportionally with the running distance, larger ones could be used Stretches (for example 30-100 cm) can be achieved a separation that exceeds all previous.

From the basic principle of overpressure layer chromatography it follows that - as with column chromatography with a solid filling - the vapors of the solvent are excluded. This leads to segregation of the solvents, especially in liquid-solid chromatography (adsorption chromatography) for the frequently used multi-component solvents, which in some cases leads to unsatisfactory separation, an accumulation of the substances to be separated from one another at the zone boundary. In high-performance column chromatography, the sorbent is preconditioned with the solvent in such cases. A suitable linear device is currently not known. The development of a linear device that is also suitable for wet processes is also desirable because it models the processes in high-performance column chromatography and allows both techniques to be used simultaneously for analytical and / or preparative purposes.

The aim of the invention is to eliminate the deficiencies described with the aid of a device for linear overpressure.

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Layer chromatography with a base plate carrying the sorbent layer.

It was found that in linear positive pressure layer chromatography, the flow rate of the solvent is constant over the entire length of the layer, which gives the possibility of developing over longer distances and thus a better separation.

Furthermore, it was recognized that the disadvantageous consequences of solvent separation, similar to high-performance column chromatography, can be eliminated by preconditioning with solvent, if necessary by applying pressure to the sample. At the same time, this is the prerequisite for modeling the separation processes in high-performance column chromatography. It has also been found that one or two directions of chromatography can be accomplished using layers of sorbent that are only sealed on the respective sides and the chromatograph has a system of openings for the introduction of solvent that can be used as needed. Finally, it was recognized that the sharpness of the separation can be improved by setting the temperature of the sorbent layer to a value which deviates from the normal downwards or upwards.

The invention accordingly relates to a device for linear overpressure layer chromatography with a base plate carrying the sorbent layer, which device has the features listed in the patent claim.

The invention is explained in more detail by means of embodiments with the aid of the drawings. Show it:

1 shows a section through an embodiment of the device according to the invention,

Fig. 2 shows a section through the capillary connections for introducing the eluent, the

2a, b, c and d further embodiments of the capillary connections in section and in plan view,

Fig. 3 shows a device for sample application, Fig. 4a, b, c and d different options for sample application and the task of the eluent.

1, the sorbent layer 1 is supported by a base plate 2 which is hollow and has connection supports 3, so that the temperature of the base plate 2 can be set exactly. The membrane 4 of the plate pressing the sorbent layer is fastened to a transparent plastic or glass plate 5. An introduction element 6 and a sample application element 7, which are designed as capillary connections and are used for introducing the sample and the eluent, adjoin the membrane. The capillary connections lead by means of seals 8 through the transparent plate 5 to the outside.

The base plate 2 and the plate 5 are pressed against one another by a pressure lock 9. A valve 11 is used to introduce the pressurized liquid or gaseous medium 10 located between the membrane 4 and the plate 5. The pressure conditions are indicated by a pressure gauge 12. The elastic pad formed on one side of the plate 5 closes the sorbent layer 1 immediately. The pressure force depends on the level of the prevailing pressure.

The seals 8 of the capillary connections enable the membrane 4 or the introduction and the sample application members 6 and 7 to move in such a way that the tightness of the pressurized space 10 remains guaranteed. 5 As can be seen from FIG. 2, the introduction member 6 used for introducing eluent connects to the membrane 4 via a cone. The tightness is achieved by a conical base 13 and a threaded nut 14.

The eluent is introduced through a groove 15 running in the sorbent layer 10. However, it is also possible to arrange a spacer 17 on the sorbent layer. In this case, the liquid enters the sorbent through the channel 18 formed between the spacer 17 and the membrane 4.

15 First, the channel 15 or the channel 18 fills, and by increasing the pressure, the linear flow begins in the sorbent layer 1, which is closed off by impregnations 19 on the side, in the direction indicated by arrows (FIGS. 2a, 2b).

The sample application element 7 shown in FIG. 3 lies directly on the sorbent layer 1. The sample introduced by overpressure flows into the sorbent. The sample can be placed in the dry sorbent layer or in the sorbent layer previously wetted with eluent. 25 The overpressure when the sample is fed in depends on the size of the pressure in the medium 10, on the size of the sorbent particles and on the viscosity ratios.

4a, b, c and d different variants of the sample application and eluent supply are shown. 30 a) one-way chromatography; the eluent entering the sorbent from the introduction member 6 through the channel 15 moves the components of the previously applied samples 20 linearly in one direction (FIG. 4a),

b) Two-way chromatography. The eluent coming from the inlet organ 6 through the channel 15 into the sorbent transports the components of the larger number of samples 20 linearly in two directions (FIG. 4b),

c) One-way chromatography, trial

40 under pressure; the eluent entering through the inlet member 6 and the channel 15 soaks or washes the sorbent layer. The sample is introduced through the sample application member 7. The flow of the eluent transports the sample linearly in a direction 45 (FIG. 4c),

d) Chromatography in two directions, test application under pressure; the eluent entering through the introducer 6 moistens the sorbent in two directions. The samples enter the sorbent layer through the sample application elements 7 arranged in two rows. The flow of the eluent transports the samples linearly in two directions.

The front of the eluent can be followed visually through the transparent plate 5. The movement of the 55 eluted components can be observed directly in the case of colored compounds and in the case of colorless compounds with the aid of labeling dyes.

The chromatogram is evaluated in the manner customary for layer chromatograms.

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4 sheets of drawings