JPH0736010B2 - Recycled liquid chromatograph - Google Patents

Description

TECHNICAL FIELD The present invention relates to a recycled liquid chromatograph. More specifically, the present invention relates to improvement of a technique for recycling and fractionating by a chromatographic method in the fields of chemical industry, medicine, food, biochemistry and the like.

(B) Conventional technique In the technique of liquid chromatography, a recycled liquid chromatograph device that can recycle the mobile phase is often used in order to improve the separation ability in consideration of the cost of the separation column, the mobile phase and the like.

This recycle liquid chromatograph is basically an analysis flow path connecting a mobile phase supply section, a sample introduction section, a separation column, a detection section and a flow path switching means in this order, and the analysis flow path from the flow path switching means. And a recycling channel connected so as to communicate with the sample inlet of the channel.

A typical example of such a recycled liquid chromatograph device is, for example, an eluent band containing a predetermined target component from the eluent transferred from the analysis channel, in addition to the above-mentioned basic configuration, in the channel switching means. An example is a recycle preparative chromatograph equipped with a fraction collector configured to collect (fractions) (see Figure 4). In the recycle preparative chromatograph apparatus, the flow path switching means is configured to be able to switch between a flow out to the fraction collector and a recycle mode for connecting to the recycle flow path.

(C) Problems to be Solved by the Invention In the above recycle liquid chromatograph apparatus and the recycle preparative chromatograph apparatus, when the apparatus is started up, the flow path switching means of the analysis flow path is replaced by a new mobile phase, and then the flow is changed. It is necessary to switch the path switching means from the flow-out to the recycle mode and replace the recycle path with the new mobile phase.

However, when the recycling flow channel is replaced with a new mobile phase, the old mobile phase retained in the flow channel is re-injected into the separation column, the old mobile phase elutes from the separation column, and the column is removed. It takes time to reach equilibrium.

This is also a problem that occurs when restarting with the mobile phase used the previous day, especially when using a refractometer detector as the detector, the baseline fluctuation becomes so large that it cannot be ignored (see Fig. 3). ).

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a recycled liquid chromatograph apparatus capable of avoiding the problems caused by the old mobile phase staying in the recycling channel during recycling.

(D) Means for Solving the Problems Thus, according to the present invention, an analysis channel having a mobile phase supply unit, a sample introduction unit, a separation column, a detection unit, and a first channel switching unit in this order, and the first channel The mobile phase, which is connected so as to communicate from the flow path switching means to at least the preceding stage of the separation column of the analysis flow path, transfers the mobile phase transferred through the analysis flow path by the switching of the first flow path switching means to the separation of the analysis flow path again. A retention old mobile phase comprising a recycle channel that can be returned to the preceding stage of the column and having a larger internal volume than the internal volume of the recycle channel in the flow channel between the recycling flow channel connection part of the analysis flow channel and the separation column. There is provided a recycled liquid chromatograph device characterized in that it is provided with a second flow path switching means capable of switchingably connecting the storage flow path.

The apparatus of the present invention can use, as a basic configuration, the flow channel configuration of a recycled liquid chromatograph that is normally used in the relevant field, except that the second flow channel switching means is provided at a predetermined site. The configuration may be modified slightly before use. For example, the connection of the recycling channel to the analysis channel is usually connected to the preceding stage of the liquid feeding means because the mobile phase supply section is composed of the mobile phase storage section and the liquid feeding means. Is only required before the separation column, and examples thereof include the space between the liquid feeding means and the sample introduction part, and the space between the sample introduction part and the separation column. However, in the case of these connections, it is necessary to provide a liquid feeding means for recycling flow in the recycling channel.

In the apparatus of the present invention, the second flow path switching means is provided between the recycling flow path connecting portion of the analysis flow path and the separation column. A storage channel for temporarily trapping the mobile phase (old mobile phase) staying in the recycle channel or the like is connected to the second channel switching means. The flow path switching means is provided so that the storage flow path can be removably connected to the analysis flow path by the switching operation. The internal volume of the storage channel is set to be larger than the internal volume of the recycle channel. An example of this capacity is, for example, a storage channel capacity of 1 ml with respect to a recycling channel capacity of 0.1 ml. The storage channel may have any configuration as long as it can store a predetermined amount of mobile phase, such as a simple pipe shape, a capillary shape, or a particle-filled column shape. It is preferable to form the coil shape in order to smoothly perform the recycling flow. In this case, the particles to be packed are selected so as not to react with the eluent. It is also possible to use, for example, a sample loop known in the art for the storage channel.

It is preferable that the fluid stored in the storage channel can be discharged to the outside of the analysis channel by switching the second channel switching means. Therefore, it is preferable to use the second flow path switching means having at least 6 connection ports, such as a high pressure 6-way valve.

The switching operation of the second flow path switching means may be configured such that a required time is measured in advance and a timer or the like is used to automatically switch.

(E) Action According to the present invention, when the old mobile phase of the flow channel system of the recycled liquid chromatograph device is replaced with the new mobile phase, the analysis flow channel is separated from the recycling flow channel by the first flow channel switching means, When the storage channel of the staying old mobile phase is inserted and connected to the analysis channel by the two-channel switching means and the new mobile phase is supplied to the analysis channel, the analysis channel is replaced with the new mobile phase.

Then, the analysis flow path is connected to the recycling flow path by the first flow path switching means to circulate the mobile phase existing in the circulation flow path composed of the analysis flow path and the recycling flow path. The old mobile phase staying in the recycle channel is pushed out as is introduced into the recycle channel, and is introduced into the storage channel via the preceding stage of the analysis channel. All the old mobile phase staying in the recycling channel is introduced into this storage channel.

Next, by the second flow path switching means, the storage channel is separated from the analysis channel by the time the old mobile phase flows out of the storage channel, so that the old mobile phase remains in the storage channel. Therefore, it is isolated from the analysis channel and the recycling channel.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

(F) Embodiment FIG. 1 is an explanatory view of the basic configuration of a recycle preparative chromatograph which is an example of the recycle liquid chromatograph device of the present invention. In the figure, the apparatus 1 comprises a mobile phase storage tank 2, a liquid feed pump 3, a high pressure 6-way valve 4, a sample injection unit 5,
An analysis channel a connecting the separation column 6, the detector 7 and the recycle valve 8 in this order, and a T-shaped tube 9 between the recycle valve 8 and the mobile phase storage tank 2 of the analysis channel a and the liquid feed pump 3. It is mainly composed of a recycle flow path b connected through the above and a fraction collector c connected to the recycle valve 8. A sample injector is attached to the sample injection unit 5.

A trap loop 41 and a drain flow path d are connected to the high-pressure 6-way valve 4. Specifically, the analysis flow path a is connected to the ports 1 and 6 of the valve 4, the trap loop 41 is connected between the ports 2 and 5, and the drain flow path d is connected to the ports 3 and 4, respectively. Therefore, the trap mode (shown by the solid line in the figure) in which the trap loop 41 can be inserted and connected to the analysis channel a by this valve 4 and the trap loop
It is possible to switch to the analysis mode (indicated by the broken line in the figure) that makes 41 independent of the analysis flow path. The trap loop 41 is made of a stainless steel tube.

In the above device 1, the internal volume of the trap loop is set to be larger than the internal volume of the recycle channel b. In this example, the internal volume of the trap loop is about 1 ml and the internal volume of the recycle channel b is about 0.1 ml. It is set.

The recycle valve 8 is set to be switchable between a recycle mode in which the analysis flow path a is connected to the recycle flow path b and a flow out mode in which the analysis flow path a is connected to the fraction collector c.

Next, the mobile phase replacement operation based on the switching operation of the high pressure 6-way valve of the device 1 will be described.

First, the recycle valve 8 is set to the flow out mode, and the high pressure 6-way valve 4 is set to the trap mode (solid line side connection).
In this state, the new mobile phase is supplied from the mobile phase storage tank 2 by driving the liquid feed pump 3 and flows out to the fraction collector c. As a result, the inside of the separation column 6 is replaced with the new mobile phase.

Next, when the recycle valve 8 is switched to the recycle mode to supply the new mobile phase, the liquid such as the old mobile phase remaining in the recycle channel b is introduced into the trap loop 41 from the T-shaped tube through the liquid delivery pump 3. It

By measuring in advance the time t _{1 at} which the accumulated liquid is completely introduced into the trap loop 41 and the time t ₂ at which the accumulated liquid starts to flow out from the trap loop 41, the high pressure 6-way valve 4 is provided between t _{1 and} t _2. Is switched to the analysis mode (connection on the broken line side), the accumulated liquid is separated from the analysis flow path a while being stored in the trap loop 41, and the analysis flow path a and the recycle flow path b are a new mobile phase. Will be replaced.

An example of the timing of switching from the trapping mode to the analysis mode will be described. For example, assuming that the volume of the liquid feed pump is 1 ml, the retained liquid is trapped in the trap loop 41 in consideration of the trap loop internal volume and the recycle channel internal volume. After about 0.37 minutes (= t ₁ ), the introduction is completed, and after about 0.66 minutes (= t ₂ ), the trap loop 41
Therefore, the high pressure 6-way valve 4 should be switched to the analysis mode during this time.

Next, in the above-mentioned device 1 configured as follows, the old mobile phase staying in the recycle channel b is trapped.
The obtained chromatograms were examined for the case of trapping in No. 41 (this example) and the case of no trapping (corresponding to the conventional example), and the results shown in FIGS. 2 and 3 were obtained.

Equipment: LC-6AD recycling system Liquid feed pump: LC-6AD High-pressure 6-way valve: Column switching valve Recycling valve: Manual recycling valve T-shaped tube: LC-6AD recycling block Recycling flow path: SUS tube 0.5mmφ × 0.5m Trap loop: SUS tube 0.8mmφ × 2m Sample injector: Model 7125 Column: Shodex K-20025 + K-2001 Detector: RID-6A Mobile phase: Chloroform Flow rate: 3.0ml / min Detection sensitivity: 1 × 10 ^-6 RIUFS (recycle) Flow channel retention liquid ... Chloroform mobile phase of the previous day) From the comparison between Fig. 2 and Fig. 3 above, it is possible to prevent the disturbance of the baseline by introducing the recycle flow channel retention liquid into the trap loop and not into the column. .

(G) Effect of the Invention According to the present invention, since the old mobile phase is not introduced into the separation column, column equilibration can be quickly achieved and aging can be shortened. Especially, in the recycle preparative chromatography, not only the aging can be shortened but also the loss of the mobile phase can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view of the basic structure of a recycle preparative chromatograph which is an example of the apparatus of the present invention, FIG. 2 is a chromatogram diagram obtained when a trap loop is used in the apparatus of FIG. 1, and FIG. Is a chromatogram diagram obtained when the trap loop is not used in the apparatus of FIG.
FIG. 4 is a view corresponding to FIG. 1 of the conventional example. 2 ... Mobile phase storage tank, 3 ... Liquid feed pump, 4 ... High pressure 6
One-way valve, 5 ... Sample injection part, 6 ... Separation column, 7 ...
… Detector, 8 …… Recycle valve, 9 …… T-tube, 41
…… Trap loop, a …… Analysis channel, b …… Recycle channel, c …… Fraction collector.

Claims (1)

[Claims] 1. A mobile phase supply unit, a sample introduction unit, a separation column,
An analysis channel having a detection unit and a first channel switching unit in this order, and a connection from the first channel switching unit to at least the preceding stage of the separation column of the analysis channel, the first channel switching unit And a recycle channel capable of returning the mobile phase transferred through the same analysis channel to the previous stage of the separation column of the same analysis channel, between the recycle channel connection part of the above analysis channel and the separation column. Recycled liquid, characterized in that the flow passage is provided with a second flow passage switching means capable of switchingably connecting a storage passage of the old retention mobile phase having an internal volume larger than the internal volume of the recycling flow passage. Chromatographic equipment.