JPH05312795A - Method and apparatus for gradient measurement - Google Patents

Abstract

PURPOSE:To obtain a method and an apparatus enabling execution of gradient measurement by a simple construction. CONSTITUTION:Moving phases A and B held in vessels 11A and 11B are sent selectively to a pump 13 through a selector valve 12. The moving phase pressurized by the pump 13 is sent to a column 4 through a selector valve 14, a reservoir 15 provided with an agitator, an injector 3 and a selector valve 16. A liquid flowing out of the column 4 is supplied to an ion source 5, while a surplus part is discharged outside through a hydraulic splitter 17. Gradient measurement can be executed by filling up the moving phase A beforehand in the reservoir 15 by using the selector valve and by supplying thereafter the moving phase B to the column through the reservoir 15.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to liquid chromatographs and, more particularly, to a method and apparatus for performing gradient measurements.

[0002]

2. Description of the Related Art FIG. 1 shows an example of a micro gradient device to which a mass spectrometer is connected as a detecting means. In FIG. 1, pumps 1 and 2 are in charge of mobile phases A and B, respectively, and mobile phases A and B from the respective pumps are merged and then supplied to a column 4 via an injector 3. The effluent from the column 4 is supplied to the ion source 5 of the mass spectrometer, and the surplus portion is discharged to the branch channel. A pump controller 6 controls the pumps 1 and 2 to accurately control the mixing ratio of the mobile phases A and B.

[0003]

When attempting to perform gradient measurement in the micro region with such a conventional device, for example, two expensive pumps capable of accurately delivering a flow rate of 1 μl / min are required, and two pumps are required. It is inevitable that an expensive system will be required because a control device for accurately interlocking control of the pumps is required.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a gradient measuring method and apparatus capable of performing gradient measurement with a simple and inexpensive structure.

[0005]

In order to achieve this object, the measuring method of the present invention uses a liquid chromatograph composed of a liquid feed pump, an injector, a separation column and a detector. In performing the measurement, a reservoir inserted in the flow path between the pump and the injector is filled with the mobile phase A in advance, and then the mobile phase B is delivered to the column via the reservoir by the delivery pump. Therefore, the gradient measurement is performed.

Further, the measuring device of the present invention comprises a separation column, a liquid feed pump for feeding the mobile phase B to the separation column, and an injector inserted in a flow path between the column and the pump. In a liquid chromatograph composed of a detector connected downstream of the separation column, a reservoir inserted in the flow path between the pump and the injector,
It is characterized in that the reservoir is provided with a first mobile phase supply channel for filling the mobile phase A in advance. Characterized by the fact that it

[0007]

In the present invention, the mobile phase A is filled in advance in the reservoir inserted in the flow path between the pump and the injector, and then the mobile phase B is delivered to the column through the reservoir by the delivery pump. The mobile phase A1
Since the proportion of the mobile phase B is gradually increased from the state of 00% and is sent to the column, gradient measurement can be performed.

An embodiment of the present invention will be described below in detail with reference to the drawings.

[0009]

FIG. 2 shows an embodiment of the present invention.
The same components as those are denoted by the same reference numerals. In FIG. 2, mobile phases A and B contained in containers 11A and 11B.
Are selectively sent to the pump 13 via the switching valve 12. The mobile phase pressurized by the pump 13 is the switching valve 1
4, it is sent to the column 4 via the reservoir 15, the injector 3, and the switching valve 16. The effluent from the column 4 is supplied to the ion source 5, and the surplus portion is discharged to the outside via the pneumatic splitter 17 described in, for example, Japanese Patent Laid-Open No. 62-241250. FIG. 3 shows a reservoir 1
5 shows an enlarged sectional view of FIG. In FIG. 3, a body 22 is attached to an L-shaped frame 21.
The piston 2 is installed in the mixing chamber 23 bored in the body 22.
4 is fitted, and the piston 24 is
By moving back and forth in the mixing chamber, the volume of the mixing chamber can be changed. Inlet 26 on the side wall of the mixing chamber
And the outlet 27 is opened at the bottom,
The mobile phase can be introduced into and discharged from the mixing chamber via the connected pipe. In addition, the stirring bar 2 is provided in the mixing chamber 23.
8 is arranged, and the mobile phase inside can be stirred by applying a rotating magnetic field or the like from the outside to rotate the stirrer 28.

An operation procedure for measurement using the above configuration will be described below. [First Step] The reservoir 15 is filled with the mobile phase A. As shown in FIG. 2, the switching valves 12, 14, 16 are set on the sides a, d, e, respectively, and the pump 13 is set to, for example, 100.
By operating at 0 μl / min, the flow path up to the switching valve 16 (including the reservoir 15) is filled with the mobile phase A. At this time, the surplus mobile phase flowing back from the pneumatic splitter side is introduced into the ion source at a flow rate of, for example, an optimum introduction amount of the ion source of about 5 μl / min, so that the ion source is maintained in an optimum operating state. [Second Step] Adsorption of Sample to Column As shown in FIG. 4, the switching valves 12, 14, 16 are set to a, d, f, respectively, and the pump 13 is set to, for example, 20 μl.
The mobile phase A is sent by operating at a flow rate of / min, and about 10 μl of the sample S is injected using the injector 3, and when the sample reaches the column inlet, the pump solution is stopped and the sample S is discharged. Adsorb at the column inlet. At this time, the sample is concentrated. [Third step] Replacing the part before the reservoir with the mobile phase B, as shown in FIG. 5, the switching valves 12, 14, 16 are replaced with b, c,
and set the pump 13 to 1000 μl, for example.
The flow path up to the switching valve 14 is replaced with the mobile phase B by operating at / min. Also at this time, the surplus mobile phase flowing back from the pneumatic splitter side is introduced into the ion source, and the ion source is maintained in the optimum operating state. [Fourth Step] Measurement As shown in FIG. 6, the changeover valves 12, 14, 16 are set to b, d,
While setting to f, the pump 13 is operated at 20 μl / min. As a result, the mobile phase B is introduced into the reservoir and at the same time sufficiently stirred with the mobile phase A by the stirrer,
Further, since it flows out from the reservoir toward the column, the composition of the mobile phase supplied to the column 4 is as shown in FIG.
At first, the mobile phase A was 100%, but the ratio of the mobile phase B gradually increased with time, and after a sufficient time, the mobile phase B can be regarded as 100%. Therefore, gradient measurement can be performed. The effluent from the column 4 is introduced into the ion source and mass analyzed.
When the measurement is repeated, the process returns to step 1.

Even if the flow rate of the pump during measurement is changed,
The gradient of the composition change shown in FIG. 7 can be adjusted by changing the capacity of the reservoir or by changing both. In this embodiment, it is possible to easily adjust the capacity of the reservoir by moving the piston back and forth. At this time, it is preferable to adjust the piston after stopping the pump and releasing the pressure, so for example, an interlock mechanism is attached to the knob for moving the piston, and when the operator touches the knob, the pump is adjusted. It is also conceivable to stop the pressure so that the pressure is released. It is also convenient if a scale is provided so that the volume can be identified by the position of the piston.

FIG. 8 shows a modification of the reservoir. In this embodiment, the two inlets 26a and 26b are changed in position.
Is provided, and the mobile phase is supplied to either of the inlets using the switching valve 29. Then, when the capacity of the reservoir is large and the piston is retracted, the inlet 26a is used, and when the capacity of the reservoir is small and the piston is advanced, the inlet 26b is used. By doing so, the stirring efficiency can be improved and the reproducibility can be improved.

Further, instead of the variable capacity reservoir, a plurality of reservoirs having different capacities may be exchanged or switched and used.

The present invention can be modified in other parts. For example, instead of the switching valve 14, a discharge valve 18 may be provided as shown in FIG. In this case, when the discharge valve 18 is opened corresponds to when the switching valve 14 is set to c in the embodiment of FIG. 2, and when it is closed corresponds to when set to d. further,
It is also conceivable to replace the positions of the injector 3 and the switching valve 16.

If a solenoid valve is used as the switching valve and the switching of the valve and the adjustment of the flow rate of the pump in each step described above are automatically performed, the operation is automated and the handling becomes easy.

Further, in the above embodiment, one pump was used to feed the liquid for measurement and to fill the reservoir 15 with the mobile phase A in advance. However, the switching valve 14 was deformed and the mobile phase A was fed from another pump. May be filled in the reservoir 15 via the switching valve 14.

[0017]

According to the present invention, gradient measurement can be performed with a simple structure of one pump and one reservoir. Moreover, since a fixed amount of liquid is sent by one pump during measurement, it is extremely stable and has good reproducibility.

[Brief description of drawings]

FIG. 1 is a diagram showing a conventional example.

FIG. 2 is a diagram showing an embodiment of the present invention.

FIG. 3 is an enlarged sectional view of a reservoir portion.

FIG. 4 is a diagram for explaining a measurement procedure.

FIG. 5 is a diagram for explaining a measurement procedure.

FIG. 6 is a diagram for explaining a measurement procedure.

FIG. 7 is a diagram showing changes over time in the composition of the mobile phase.

FIG. 8 is a view showing a modified example of the reservoir.

FIG. 9 is a diagram showing another embodiment.

[Explanation of symbols]

 3 Injector 4 Separation Column 5 Ion Source 11A, 11B Mobile Phase Container 12, 14, 16 Switching Valve 13 Liquid Transfer Pump 15 Reservoir 17 Pneumatic Splitter

Claims (2)

[Claims] 1. When performing gradient measurement using a liquid chromatograph composed of a liquid feed pump, an injector, a separation column, and a detector, the liquid chromatograph is inserted into a flow path between the pump and the injector. The gradient measurement is performed by preliminarily filling a mobile phase A in a reservoir, and then feeding the mobile phase B to the column through the reservoir by the liquid delivery pump. Measuring method. 2. A separation column and a mobile phase B to the separation column.
In a liquid chromatograph composed of a liquid feed pump for feeding a liquid, an injector inserted in the flow path between the column and the pump, and a detector connected downstream of the separation column, the pump A gradient measuring device comprising: a reservoir inserted into a flow path between the injector and the injector; and a first mobile phase supply flow path for filling the mobile phase A in advance in the reservoir.