JPH0376867B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a sample introduction device for liquid chromatography.

[Conventional technology]

BACKGROUND ART Some liquid chromatographs used in amino acid analyzers and the like employ a center injection method as a device for introducing a sample into a column. FIG. 6 is a system diagram showing a conventional liquid chromatography sample introduction device.

In the drawing, 1 is a column filled with resin, with a central nozzle 2 at the center of the top, a side inlet 3 at the periphery of the top, and an outflow pipe 4 at the bottom.
are connected to each other. 5 is (dual method)
In the buffer pump, a branch pipe 6a of the discharge pipe 6 is connected to the central nozzle 2 via a sampling valve 7, and a branch pipe 6b is connected to the side inlet 3 via a resistor 8. The sampling valve 7 has a sample holding tube 7b in the rotor 7a, which is connected between the branch pipe 6a and the central nozzle 2 in one rotational position and between the pipette 9 and the sampling pump 10 in the other rotational position. It's starting to connect. 1
1 is a sample tube.

In the above configuration, the sampling valve 7 drives the sampling pump 10 in the state shown in the figure, and the sample is aspirated from the sample tube 11 by the pipette 9 and introduced into the sample holding tube 7b. After sampling, when the sampling valve 7 is switched to the position indicated by the broken line, the developing liquid sent from the buffer pump 5 is divided by the resistor 8, and the developing liquid passing through the branch pipe 6a transfers the sample in the sample hold tube 7b from the central nozzle 2 to the column 1. into the branch pipe 6
The developing solution passing through b is introduced from the side inlet 3 to the upper periphery of the column 1 and is uniformly developed.

[Problem that the invention seeks to solve]

In the conventional device described above, the developing liquid is dispensed by the resistor 8, so the amount of developing liquid tends to change slightly, and a filter of several microns or less is installed at the tip of the center nozzle 2 to prevent the resin from flowing back. However, there was a problem in that injection resistance increased due to foreign matter adhering to the filter, resulting in injection failure.

[Means for solving problems]

This invention is intended to solve the above problems, and by combining a buffer pump having two pump bodies and a specific sampling valve, it is possible to avoid changing the amount of developing solution sent for introducing the sample. Provided is a sample introduction device for liquid chromatography that can accurately and reliably forcefully introduce a sample into a column.

The present invention is a sample introduction device for liquid chromatography, which introduces a sample into a central nozzle provided at the center of the upper part of a column, and introduces a developing solution into a side inlet provided at the periphery of the upper part of the column. a buffer pump having first and second pump bodies; piping for introducing developing liquid sent from the first pump body into the side inlet; and a discharge side of the second pump body. a sampling valve connected to the sampling valve; a sample hold part connected to the sampling valve; a first channel formed in the sampling valve so as to sample the sample hold part; A second flow path formed in the sampling valve so as to introduce the developing solution into the side inlet, and a sampling valve configured to introduce the developing solution from the second pump body into the central nozzle through the sample holding section after sampling. a third flow path formed in the first and second switching positions of the sampling valve; a second flow path formed in the second switching position; forming the second and third flow paths at the switching position;
This is a sample introduction device for liquid chromatography, characterized by comprising a switching means provided on the sampling valve so as to form a third flow path at the switching position of the sampling valve.

[Effect]

In the liquid chromatography sample introduction device configured as described above, a buffer pump delivers a developing solution, and the developing solution delivered by the first pump body is introduced into the side inlet of the column. . On the other hand, in the sampling valve, the first switching position is set by switching the switching means.
Sampling is carried out from the flow path into the sample holding section, and the developing solution sent from the second pump body is introduced from the second flow path into the side inlet of the column. At the second switching position, sampling by the first channel is stopped, and the developing solution sent from the second pump body is sent from the second channel to the side inlet. In the third switching position, part of the developing solution is sent from the second channel to the side inlet, and the remainder of the developing solution is sent to the third channel, thereby removing the sample in the sample holder. is introduced into the central nozzle of the column. In the fourth switching position, the supply of the developing solution to the second channel is stopped,
The sample is introduced by sending the liquid to the third channel.

This allows the sample to be introduced into the column without changing the flow rate of the developing solution.
The sample can be forcibly introduced into the column accurately and reliably, and the liquid delivery by the second pump body does not stop during sampling and switching, and noise due to pressure fluctuations does not occur.

〔Example〕

1 to 4 are system diagrams showing different operating states of an embodiment of the present invention, and FIG. 5 is a perspective view of a sampling valve, and the same reference numerals as in FIG. 6 indicate the same or corresponding parts.

The buffer pump 5 is a pump that operates a first pump main body 5a and a second pump main body 5b by one driving part, and the suction side is connected to the same developing liquid supply source, and is a dual pump with high pressure and constant flow rate similar to the conventional one. A plunger pump can be used. The discharge side of the first pump body 5a is connected to the side inlet 3 of the column 1 via piping 12a, and the discharge side of the first pump body 5a is
The discharge side of b is connected to the stator 7c of the sampling valve 7 through a pipe 12b.

The sampling valve 7 is configured such that a rotor 7a repeatedly rotates at an angle α below a stator 7c. The rotor 7a has a sliding surface 7d to a lower end surface 7.
Axial flow paths 13a, 1 on the same circumference leading to e.
3b, 13c are provided, and flow paths 13a, 1
A sample hold tube 7b is connected between the lower ends of the flow path 13c, and the lower end of the flow path 13c is connected to the side inlet 3 by a pipe 12c.

The stator 7c has an axial flow passage 14a on the same circumference as above, extending from the upper end surface 7f to the sliding surface 7d.
14b, 14c, 14d and a flow path 14e branching in an inclined direction from the upper end of the flow path 14d, and grooves 15b, 15d and the flow path extending rightward on the same circumference from the lower ends of the flow paths 14b, 14d. 1
A groove 15e is formed extending in the opposite direction from 4e. The upper end of the channel 14a is connected to the pipette 9,
The upper end of the flow path 14b is connected to the central nozzle 2 via the piping 12d, the upper end of the flow path 14c is connected to the sampling pump 10, and the upper ends of the flow paths 14d and 14e are merged and connected to the second through the piping 12b. It is connected to the pump body 5b. Further, the lower ends of the channels 14a to 14e and the grooves 15b, 15d, and 15e are connected to the rotor 7.
When a rotates, it coincides with the upper ends of the channels 13a to 13c.

In the liquid chromatography sample introduction device configured as described above, when performing an analysis, the buffer pump 5 is driven, and the first and second pump bodies 5a and 5b supply a developing solution from the same developing solution supply source. The liquid is delivered. Of these, the developing liquid sent by the first pump main body 5a is always supplied to the pipe 12a.
is introduced into side inlet 3 of column 1 from
The developing liquid sent by the second pump main body 5b is supplied to the sampling valve 7 from the piping 12b.

When the measurement is started, the rotor 7a of the sampling valve 7 rotates by an angle α from the A position to the B position to sample and introduce the sample, and the rotor 7a remains at the B position until one measurement is completed. Stay in. After the measurement is completed, the rotor 7a is returned from the B position to the A position to prepare for the start of the next measurement. Hereinafter, the state of sampling and introduction accompanying switching from the A position to the B position will be explained.

At the start of measurement, the rotor 7a is at position A in FIG. 5, and the sampling valve 7 is in the state shown in FIG. At this time, the flow paths 13a and 14a, the flow paths 13b and 14c, and the flow path 13c and the groove 15e are aligned, and the sampling pump 10 sucks the sample from the pipette 9 into the sample hold tube 7b to perform sampling. The developing solution from the main body 5b is introduced into the side inlet 3 from the flow paths 14e and 13c through the piping 12c.

When the rotor 7a rotates and reaches the state shown in Fig. 2,
Both ends of the sample hold tube 7b are valve-cut to complete sampling, but the developing liquid in the second pump body 5b is introduced into the side inlet 3 as before. When the rotor 7a further rotates, the state shown in FIG. 3 is reached, and the flow paths 13a and 14b,
The flow paths 13b and 14d and the flow paths 13c and 14e coincide, and part of the developing liquid sent from the second pump main body 5b is introduced into the side inlet 3 from the flow paths 14e and 13c, and the other part is introduced into the side inlet 3 through the flow paths 14e and 13c. The operation of extruding the sample in the sample holding tube 7b from the channels 14d and 13b and introducing the sample into the central nozzle 2 from the channels 13a and 14b through the piping 12d is started.

When the rotor 7a further rotates and reaches position B in FIG. 5, the flow paths 13c and 14e are blocked as shown in FIG. 4, and the flow path 13a and groove 15b are aligned, and the flow path 13b and groove 15d are aligned. All the developing liquid sent from the second pump body is transferred to the sample hold tube 7b.
The sample inside the nozzle is fed to the central nozzle 2. The switching from the state shown in FIG. 1 to the state shown in FIG. 4 is instantaneous and is one step, but during the switching, the developing liquid from the second pump main body 5b is temporarily transferred to the sample hold tube 7b. Because it flows to both side inlets 3 and there is no stoppage of liquid feeding,
No pressure fluctuations occur beyond the column.

In the state shown in FIG. 4, the developing liquid from the second pump main body 5b flows only into the sample holding tube 7b, and the sample is forcibly introduced into the central nozzle 2, and is not affected by pressure fluctuations in other systems. Sample injection is performed accurately and reliably even when the injection resistance of the filter increases. During this time, the developing solution is introduced into the side inlet 3 from the first pump main body 5a, and is developed in the column 1.

After the injection is completed, the rotor 7a is reversed from the B position to the A position, performs sampling in the state shown in FIG. 1, and waits.

In the above device, sample hold tube 7
The sample in b is forced into column 1 by an independent flow system.
Since it can be injected into the column 1 accurately and reliably without being affected by other flow systems. Further, by using the sampling valve 7, stable injection can be performed without stopping the flow of the developing liquid in the second pump main body 5b and without increasing the number of valves. Furthermore, the entire volume of the valve-cut sample can be continuously injected without dividing it.

In the above description, the sampling valve 7 is used to introduce the sampling sample into the central nozzle of the column 1 using the developing solution sent from the second pump main body 5b after sampling, and to The present invention is not limited to what is shown in the drawings, as long as the developing solution fed from the second pump main body 5b is introduced into the side inlet 3 and the liquid feeding is not interrupted.

〔Effect of the invention〕

According to the present invention, by combining a buffer pump having two pump bodies and a specific sampling valve, the sample can be forcibly and accurately transferred without changing the amount of the developing solution for introducing the sample. can be introduced into the column,
There is no noise due to pressure fluctuations or sample division, allowing for highly accurate analysis.

[Brief explanation of drawings]

1 to 4 are system diagrams showing different operating states of an embodiment of the present invention, FIG. 5 is a perspective view of a sampling valve, and FIG. 6 is a system diagram of a conventional device. In each figure, the same reference numerals indicate the same or equivalent parts, 1 is the column, 2 is the central nozzle, 3 is the side inlet, 5 is the buffer pump, 5a is the first pump body, 5b is the second pump body, 7 is a sampling valve, 7a is a rotor, 7b is a sample holding tube, 7c is a stator, 7d is a sliding surface, 9 is a pipette, 10 is a sampling pump,
12a to 12d are piping, 13a to 13c, 14a
14e are channels, and 15b, 15d, and 15e are grooves.

Claims (1)

[Claims] 1. A liquid chromatography system in which a sample is introduced into a central nozzle provided at the center of the top of a column, and a developing solution is introduced into a side inlet provided at the periphery of the top of the column. A sample introduction device comprising: a buffer pump having first and second pump bodies; piping for introducing a developing solution sent from the first pump body into the side inlet; and the second pump body. a sampling valve connected to the discharge side of the pump; a sample hold part connected to the sampling valve; a first channel formed in the sampling valve so as to sample to the sample hold part; A second flow path is formed in the sampling valve so as to introduce the developing solution into the side inlet, and a second flow path is formed in the sampling valve so as to introduce the developing solution from the second pump body into the central nozzle through the sample holding section after sampling. a third flow path formed in the sampling valve in a first switching position of the sampling valve; forming the first and second flow paths in a first switching position of the sampling valve; , forming second and third flow paths in a third switching position;
1. A sample introduction device for liquid chromatography, comprising: a switching means provided on a sampling valve so as to form a third flow path at a switching position of the sampling valve. 2. The sampling valve includes a rotor having a flow path connecting to both sides of the sample holding tube and a flow path connecting to the side inlet, a flow path connecting to the pipette, a flow path connecting to the central nozzle, and a flow path connecting to the sampling pump. and a stator having two flow passages connected to the second pump body, and the respective flow passages are switched to be sequentially connected by rotation of the rotor. Sample flow introduction device for liquid chromatography. 3. A sample introduction device for liquid chromatography according to claim 2, wherein the flow path connected to the central nozzle and the flow path connected to the second pump body have grooves on the sliding surface with the rotor. . 4. A sample introduction device for liquid chromatography according to any one of claims 1 to 3, wherein the buffer pump is a double plunger pump.