JPH1123557A - Liquid chromatograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily grasp the solvent flows of a passage system by measuring the liquid quantities of the solvents sucked by a liquid feed pump, and displaying the liquid quantity measured results on the same time base concurrently with the chromatogram display of the detected result of a detector. SOLUTION: Solvents 2, 12 are stored in solvent sumps 1, 11 for gradient elution, the solvent sump 1 is connected to a liquid quantity measuring means 7 at a low position through a pipe 3, a solenoid valve 4, and a pipe 6, and the solvent 2 is guided into the liquid quantity measuring means 7 by gravitational force. The liquid quantity measuring means 7 is filled with the solvent 2, the solenoid valve 4 is switched to a dense plug 5 side to start a liquid feed pump 9, and the solvent 2 is discharged to a mixer 21 through a pipe 10. The liquid level reduction per unit time of the solvent 2 in the liquid quantity measuring means 7 by the suction of the liquid feed pump 9 is measured, and the suction liquid quantity of the liquid feed pump 9 is found. The suction liquid quantity is likewise formed for the solvent sump 11. They are displayed together with chromatogram, and the elution peak and flow from a separation column 25 can be concurrently monitored.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid chromatograph, and more particularly, to a liquid chromatograph capable of monitoring a flow rate (flow rate) of a solvent as a mobile phase during liquid chromatographic measurement. The present invention relates to a liquid chromatograph device having improved liquid chromatography. In particular, the present invention relates to a so-called gradient elution method in which the mixing ratio of a plurality of solvents is changed with time using a plurality of liquid sending pumps. The present invention also relates to a liquid chromatograph device which is suitable for such applications.

[0002]

2. Description of the Related Art Liquid chromatographs have been widely used in the field of qualitative and quantitative determination of trace components, but they are used for components such as a liquid reservoir of a mobile phase, a liquid sending pump, a separation column, and a detector. The flow rate of the solvent flowing through the flow path system constituted by the pipes communicating with the above only depends on the setting of the liquid sending amount of the liquid sending pump.

[0003]

However, there is no guarantee that the set value of the liquid sending amount in the liquid sending pump is the same as the actual flow rate in the flow path system of the liquid chromatograph. For example, when the liquid feed pump breaks down, the flow rate of the solvent greatly deviates from the set value, and measurement is performed at an unexpected flow rate of the solvent.

In a so-called gradient elution method in which a plurality of kinds of solvents are sent using a plurality of sending pumps and the mixing ratio of the solvents is changed continuously or stepwise, a set value of the mixing ratio of the solvents is detected. Although it is also displayed in the chromatogram together with the detection result in the analyzer, it is simply a display of the set value and not a display based on the actual flow rate of each solvent, so the composition of the solvent actually flowing It does not reflect that. In addition, even if one of the liquid feeding pumps fails, it is difficult to detect this from the outside.

In a liquid chromatograph, the qualitative / quantitative determination of a component in an unknown sample is often determined by comparing it with the peak elution time in a chromatogram of a known component in a standard sample, ie, elution volume. If the amount of fluid in the graph channel system changes, or if the mixing ratio of the solvent in the gradient elution method changes, the reproducibility of the results deteriorates, and there is a problem that incorrect qualification or the like is performed.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a reliable measurement data by easily grasping the flow rate of a solvent flowing in a flow channel system during liquid chromatography measurement in view of the above-mentioned problems of the prior art. It is to provide a liquid chromatograph device.

[0007]

A liquid chromatograph apparatus according to the present invention, which has been made to solve the above-mentioned problems, has a separation column and a detector, and a solvent in a solvent reservoir is analyzed by a liquid sending pump. In a liquid chromatograph apparatus for detecting an eluate from a separation column after supplying a sample to be separated to a separation column, the liquid chromatograph for measuring the amount of the solvent sucked into the liquid sending pump between the solvent reservoir and the liquid sending pump is used. A liquid-volume measuring means, wherein the detection result of the detector is displayed as a chromatogram having a time at which a sample to be analyzed is injected as a starting point on a time axis, and the liquid volume measurement is performed on the same time axis as the chromatogram. A liquid chromatograph apparatus characterized by displaying the measurement results of the means together, in particular, a plurality of liquid sending pumps and a plurality of solvent reservoirs for sending a plurality of kinds of solvents, and Comprising a number of liquid measurement device is a liquid chromatograph apparatus characterized by measurement of liquid quantity measuring means for displaying together for each solvent when displaying a chromatogram. The display includes, for example, a chromatogram display on a screen, a printer, or the like, as well as storage in a suitable storage means, such as a floppy disk.

The measurement result of the liquid amount measuring means displayed on the chromatogram is preferably a liquid amount per unit time in a liquid chromatograph apparatus, that is, a flow rate of a solvent. In this way, by displaying the flow rate in the chromatogram, it is possible to simultaneously monitor the change in the flow rate and the state of the elution peak in the chromatogram.

The liquid amount measuring means is not limited as long as it can measure the amount of liquid passing therethrough, and an ordinary liquid amount meter or the like can be used. Above all, a type comprising a solution reservoir having a constant cross-sectional area in an arbitrary direction and a sensor for measuring the liquid level of the solvent in the solution reservoir has a relatively simple configuration. It is particularly preferable since the flow rate can be easily calculated from the change in the liquid level per unit time. Here, the calculation of the flow rate can be performed by the liquid amount measuring means provided that the time measuring function is provided with the time measuring function. In addition, for example, the operation of each component configuring the liquid chromatograph apparatus may be performed. May be provided with a timing function according to a control device for controlling the time.

In addition to monitoring the flow rate of the solvent in the flow path system as described above, the liquid chromatograph apparatus of the present invention compares the calculated flow rate with the flow rate set in the liquid sending pump, and compares the two with each other. If they are different from each other, it is also possible to perform a feedback control to temporarily increase or decrease the amount of liquid to be sent by the liquid sending pump to make them equal. For this purpose, the number of rotations of a motor or the like which is a driving source of the liquid sending pump may be increased or decreased. A normal computer (CPU) or the like may be used as the control means, but a function relating to a control device for controlling the operation of each component constituting the liquid chromatograph device may be provided.

The flow rate slightly fluctuates due to the inner diameter of the pipe constituting the flow path system of the liquid chromatograph apparatus, its elasticity, and pulsation inherent in the liquid feed pump even if no failure occurs in the liquid feed pump. . Therefore, when performing the above-described feedback control, it is determined whether or not the calculated flow rate of the solvent is within an allowable range calculated based on the flow rate set in the liquid sending pump, and the value is out of the allowable range. In this case, it is particularly preferable to perform feedback control to temporarily increase or decrease the amount of liquid to be sent by the liquid sending pump so that the value falls within an allowable range. Usually, the allowable range may be determined by adding and subtracting a flow rate that can fluctuate for the above-described reason with reference to a set value of the liquid feed pump.

In the liquid chromatograph device of the present invention, a warning may be issued when the calculated flow rate is out of the above-mentioned allowable range, or a special display may be made in the chromatogram. .

As described above, the liquid chromatograph of the present invention includes a separation column, a detector, a liquid pump, and the like. Examples of the separation column include columns packed with various packing materials for liquid chromatography, such as for size exclusion chromatography, ion exchange, reverse phase chromatography, and affinity chromatography. In the present invention, a guard column such as an adsorption column, a sample concentration column, and the like may be provided before and after the separation column. The detector may be appropriately selected and used in relation to the components in the sample to be qualitatively and quantitatively determined by a liquid chromatograph device. Examples thereof include an absorbance detector, a fluorescence detector, a transmitted light detector, and a differential refraction detector. A rate detector and the like can be exemplified. In addition, for detection by the detector, a part of the pipe in the liquid chromatograph device may be a flow cell formed of a transparent or translucent member. Examples of the liquid feed pump include a pump using a piston and a syringe and a peristaltic pump.

According to the structure of the present invention, not only the abnormality of the liquid feed pump and the gradient abnormality in the liquid chromatograph device can be easily judged, but also the actual flow rate and the actual liquid composition can be monitored simultaneously with the chromatogram, so that the reliability of the measurement can be improved. Is improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 schematically shows a liquid chromatograph apparatus of the present invention. Solvent reservoir for solvent 1,11
Contains different solvents 2 and 12 so that gradient elution can be carried out. Solvent reservoir 1
It is connected to a liquid amount measuring means 7 through a pipe 3, an electromagnetic valve 4, and a pipe 6. Here, the liquid amount measuring means 7 is arranged lower than the solvent reservoir 1, and when the electromagnetic valve 4 is switched to the pipe 6, the solvent 2 is guided to the means 7 by weight.
After filling the solution reservoir of the liquid volume measuring means 7 with the solvent 2, the electromagnetic valve 4 is switched to the sealed stopper 5 side, and the solvent reservoir 1 and the liquid volume measuring means 7 are switched.
The flow path between them is closed, and the liquid feed pump 9 is started. Thereby, the solvent stored in the solution reservoir of the liquid amount measuring means is
The mixture is discharged to a mixer (mixing tank for generating a gradient) 21 through a pipe 10.

As the solvent is sucked by the liquid sending pump 9, the liquid level of the solvent stored in the solution reservoir in the liquid amount measuring means 7 decreases. Therefore, by measuring the change in the liquid level per unit time, it is possible to calculate the amount of liquid sucked by the liquid sending pump 9. The liquid volume of the solvent reservoir 11 can be similarly calculated.

In this embodiment, the case where a gradient elution method using two liquids of the solvents 2 and 12 is described. For example, an apparatus using one liquid is provided by omitting one flow path system. can do. Conversely, by adding a similar flow path system (for example, a flow path from the solvent reservoir 1 to the pipe 10), it is possible to provide a device adapted to a gradient elution method using more than two solvents.

The liquid mixed in the mixer 21 is supplied to the pipe 2
2. Separation column 25 via sample injection means 23 and pipe 24
To be served. The eluate from the separation column 25 is supplied to a pipe 26
After being detected by the detector 27 after passing through, the waste liquid is discharged through the waste liquid pipe 28. In the liquid chromatograph device of the present invention,
By monitoring the liquid amount of each of the solvents 2 and 12 supplied to the mixer 21, the actual composition ratio of the solvent mixed in the mixer 21 can be monitored.

FIG. 2 shows the relationship between the liquid amount measuring means and the control device. The measured values of the liquid amount (liquid level) from the liquid amount measuring means 7 and 17 are periodically sent to the CPU 31 every 10 seconds. Sent. The CPU 31 having received the measured value performs a calculation for converting the measured value into a flow rate of the solvent. That is, assuming that the measured value of the liquid amount measuring means 7 at time t1 is h1 and the measured value at time t2 is h2, the liquid amount sucked by the liquid sending pump 9 between t2 and t1 is as high as h1-h2. T2-t
The flow rate f1 per hour is (h1−h2) × liquid amount measuring means 7
The cross-sectional area of the liquid reservoir in the inside / (t2-t1) is calculated. At the same time, the flow rate f2 in the liquid amount measuring means 17 is t1
Assuming that the measured value at time is h3 and the measured value at t2 time is h4, it is calculated as (h3-h4) .times.cross-sectional area of the liquid reservoir in the liquid amount measuring means 17 / (t2-t1). By adding the calculated f1 and f2, it is possible to determine the flow rate that has flowed through the flow path system of the liquid chromatograph during the time t2-t1. Also, f1
If the ratio between f2 and f2 is converted into a percentage by, for example, calculation of f1 × 100 / (f1 + f2), the ratio of the solvent sent from the liquid sending pump 9 and the liquid sending pump 19 at time t2−t1, that is, liquid chromatography The composition C of the liquid flowing through the channel system in the graph can be determined.

[0020] The liquid chromatograph apparatus of the present embodiment uses a solvent 2
In order to perform the gradient elution according to the steps (a) and (b), a setter 29 is provided for controlling the liquid sending pumps 9 and 19 so that the liquid sending amount is set in advance. Therefore, the liquid compositions c1% and c2 at the times t1 and t2 set in the setting device 29 are set.
% From the average value (C%) and the set liquid feed amounts (F1, F2) set in the respective liquid feed pumps.
The amount of the solvent to be sent during the period from t2 to t1 is calculated and compared with the amount of the liquid measured by the liquid amount measuring devices 7 and 17 and calculated by the CPU 31. For example, when the liquid sending pump 9 is at t2
The amount of liquid F1 that must be delivered at -t1 time is F ×
It can be calculated by C / 100. Similarly, the liquid sending pump 19 is set to t2
-The amount of liquid F2 that must be delivered at time t1 is Fx
It can be calculated as (1-C) / 100. When F1 is larger than the value of f1, it is determined that the liquid sending amount of the liquid sending pump 9 is smaller than the set value.
Is issued to increase the rotation speed of the motor 32 for driving the motor. F
When the value of 1 is smaller than the value of f1, it is determined that the amount of liquid supplied by the liquid supply pump 9 is larger than the set value, and an instruction to reduce the rotation is issued to the motor 32. The same applies to the control of the liquid feed pump 19. In this example, the comparison is made with respect to F1 and F2 with an allowable range of ± 1%.

Normally, the amount of liquid to be sent from each of the liquid sending pumps in the case of performing the gradient elution method is determined by the set value of the setter 29. In this example, by using the liquid amount measuring means 7 and 17, Since the actual flow rate of the flow path system can be known, the solvent composition based on the set value and the actual solvent composition based on the actual flow rate can be compared and calibrated.

FIG. 3 shows an example in which a chromatogram 35 and a flow rate 36 are displayed on a screen 34. in this way,
From the display, it can be immediately determined whether or not the liquid supply of the liquid supply pump is being performed as set.

FIG. 4 shows an example in which a chromatogram 38 in the liquid chromatograph apparatus shown in FIG. 1 is displayed on a screen 37 together with a solvent mixing ratio (composition ratio) 39. From this display, it can be immediately determined whether or not the solvent composition is in accordance with the set gradient composition.

FIG. 5 is a view showing a liquid chromatographic apparatus of the type used as the liquid amount measuring means 7 or 17 in the liquid chromatograph of FIG. 1 for measuring the liquid amount from the liquid level of the solvent. It is composed of a liquid measuring tube 40 having a known capacity, a plurality of light sources 41 for measuring the liquid level, and a plurality of sensors 42 for measuring the liquid surface. It is to measure.

[0025]

As described above, according to the liquid chromatograph of the present invention, the amount of the solvent flowing in the flow channel system can be displayed together with the chromatogram, so that the elution peak from the separation column can be displayed. And the flow rate can be monitored simultaneously. Also, when performing a gradient elution method using a plurality of liquid sending pumps, calculate the flow rate of each solvent and the ratio of the solvent actually supplied to the separation column,
This can be displayed simultaneously with the chromatogram.

Therefore, when the liquid supply pump is out of order or when the liquid supply and analysis are not performed according to the set values, such as when a failure occurs in the liquid supply pump or when no gradient is formed, this can be immediately detected.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a liquid chromatograph device according to the present invention.

FIG. 2 is a diagram for explaining feedback control in the liquid chromatograph device of the present invention.

FIG. 3 is a diagram showing an example of display by the liquid chromatograph device of the present invention.

FIG. 3 is a view showing an example of display by the liquid chromatograph device of the present invention.

FIG. 5 is a view showing a liquid amount measuring means of the type for measuring the liquid amount from the liquid level of the solvent, which is used as the liquid amount measuring means 7 or 17 in the liquid chromatograph apparatus of FIG. 1; .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solvent reservoir 2 Solvent 3 Pipe 4 Electromagnetic valve 5 Seal plug 6 Pipe 7 Liquid volume measuring means 8 Pipe 9 Liquid feed pump 10 Pipe 11 Solvent reservoir 12 Solvent 13 Pipe 14 Electromagnetic valve 15 Seal plug 16 Pipe 17 Liquid quantity measuring means 18 Pipe 19 Send Liquid pump 20 Feedback control cable 21 Mixer 22 Piping 23 Sample injection means 24 Piping 25 Separation column 26 Piping 27 Detector 28 Waste liquid piping 29 Setting device 31 CPU 32 Motor 33 Motor 34 Display screen 35 Chromatogram 36 Solvent flow rate 37 Display screen 38 Chromatogram 39 Composition ratio of solvent 40 Liquid volume measuring tube 41 Light source for liquid level measurement 42 Sensor for liquid level measurement

Claims (6)

[Claims] 1. A liquid chromatograph having a separation column and a detector, wherein a solvent in a solvent reservoir and a sample to be analyzed are supplied to the separation column by a liquid sending pump, and then the eluate from the separation column is detected. The apparatus has a liquid amount measuring means for measuring the liquid amount of the solvent sucked into the liquid sending pump between the solvent reservoir and the liquid sending pump, and injects a sample whose detection result by the detector is to be analyzed. A liquid chromatograph apparatus characterized in that, when displaying as a chromatogram with time as a start point of a time axis, the measurement result of the liquid amount measuring means is also displayed on the same time axis as the chromatogram. 2. A method according to claim 1, further comprising a plurality of liquid supply pumps for supplying a plurality of kinds of solvents, a plurality of solvent reservoirs, and a plurality of liquid amount measuring means, wherein a liquid amount of each solvent is measured when displaying a chromatogram. 2. The liquid chromatograph apparatus according to claim 1, wherein the measurement result of the means is also displayed. 3. The liquid amount measured by the liquid amount measuring means,
3. The liquid chromatograph device according to claim 1, wherein a flow rate of the solvent in the liquid chromatograph device is calculated and displayed. 4. The liquid chromatograph apparatus according to claim 1, wherein the liquid amount measuring means comprises a solution reservoir and a sensor for measuring the liquid level of the solvent in the solution reservoir. 5. The calculated flow rate of the solvent in the liquid chromatograph is compared with the flow rate set in the liquid sending pump, and when both are different, the liquid sending amount in the liquid sending pump is temporarily increased or decreased. 3. The liquid chromatograph apparatus according to claim 1, further comprising control means for performing feedback control for making the two equal. 6. The control means determines whether or not the calculated flow rate of the solvent is within an allowable range calculated based on the flow rate set in the liquid sending pump, and when the value is out of the allowable range. 3. The liquid chromatograph apparatus according to claim 1, further comprising: a control unit configured to perform a feedback control to temporarily increase or decrease a liquid sending amount in the liquid sending pump so that the value falls within an allowable range.