JP4196516B2 - Liquid chromatograph - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid chromatograph for separating and analyzing various compounds in a sample, such as a high performance liquid chromatograph (hereinafter referred to as HPLC).
[0002]
[Prior art]
FIG. 1 is a schematic flow path configuration diagram showing a conventional HPLC.
The sample is collected from the column 5 for separating the sample, the pump unit 1 for feeding the mobile phase to the column 5, and the sampling needle 39 to the sampling loop 27, and the collected sample is switched to the column 5 by switching the flow path switching valve 29. The auto-injector 3 introduced into the upstream mobile phase flow path, the detection unit 7 for detecting the sample separated by the column 5, and the control unit 41 for controlling the operation of the pump unit 1 and the auto-injector 3. .
[0003]
The autoinjector 3 is provided with a 2-position 6-port valve 29 for switching the flow path from the pump unit 1 to the sampling loop 27 or the column 5 for connection. The sampling loop 27 is connected to a sampling needle 39 that moves between the injection port 35 and the sample container 37, sucks the sample from the sample container 37, and discharges the sample to the injection port 35. The injection port 35 is connected to the column 5 by switching the valve 29. A metering syringe 33 is connected to one port of the valve 29 via a three-way valve 31, and is connected to the sampling loop 27 by switching the valve 29.
[0004]
A cleaning port 47 to which a cleaning solution for cleaning the outside of the sampling needle 39 is supplied after the sampling needle 39 sucks the sample is provided. A cleaning liquid is appropriately supplied to the cleaning port 47, and an excessive amount of cleaning liquid is discharged.
A detection unit 7 that detects the sample separated by the column 5 is connected downstream of the column 5.
Thin tubes are used in the flow path between the injection port 35 and the valve 29, the flow path between the valve 29 and the column 5, and the flow path between the column 5 and the detection unit 7 in order to prevent dilution of the sample.
[0005]
In this conventional example, when the mobile phase is filled with the entire flow path or the mobile phase is replaced when the apparatus is started up, the volume of the inside of the pump unit 1 is relatively large, so that the mobile phase is at a low speed as usual. If it is flowed, it will take much time to replace the mobile phase inside the pump. However, if the mobile phase is allowed to flow at a high speed, the pressure after the injection port 35 including the column 5 is so thin that the pressure increases. For this reason, the mobile phase cannot flow at high speed in the flow path after the injection port 35. Therefore, a drain valve is provided in the pump unit 1, and after switching the drain valve to the drain side, the pump is driven at high speed to introduce a mobile phase into the pump.
[0006]
[Problems to be solved by the invention]
Since manually opening and closing the drain valve for filling or replacing the mobile phase is a complicated operation for the operator, automation is desired. However, when attempting to automate the opening and closing of the drain valve, a high torque motor is required because a high pressure is applied to the drain valve, which increases the cost of the apparatus.
Therefore, it is conceivable that the mobile phase is discharged from the sampling needle 39 when the mobile phase is filled or replaced. However, since the mobile phase from the sampling needle 39 can only be discharged to the cleaning port 47, the cleaning port 47 may be contaminated with the mobile phase this time.
The object of the present invention is to prevent contamination of the washing port.
[0007]
[Means for Solving the Problems]
The liquid chromatograph of the present invention includes a column for separating a sample, a liquid feeding part for feeding a mobile phase to the column, and a suction / discharge member, and takes a sample from a sampling needle to a sampling loop. A sample introduction section that switches the flow path switching valve and introduces it into the mobile phase flow path upstream of the column, a detection section that detects the sample separated by the column, and a control section that controls the operation of the liquid feeding section and the sample introduction section a liquid chromatograph equipped with bets are those having a drain port for discharging the liquid discharged from the sampling needle to the outside.
Further, the cleaning port can be provided that stores the supplied cleaning liquid and discharges an excessive amount of cleaning liquid to the drain port.
[0008]
In the present invention, since the drain port for discharging the mobile phase from the sampling needle and the cleaning port for storing the cleaning liquid are provided separately, the cleaning port can be prevented from being contaminated by the mobile phase, The outside of the needle, that is, the sample can be prevented from being contaminated with the mobile phase.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
In addition to controlling the analysis operation by each unit, the control unit switches the flow path switching valve to connect the liquid feeding unit to the sampling needle through the sampling loop, positions the sampling needle to the drain port, and drives the liquid feeding unit Is also controlled to perform a cleaning operation outside the sampling needle by allowing the sampling needle to enter the cleaning liquid stored in the cleaning port.
[0010]
When a signal for filling the mobile phase in the flow path or a signal for exchanging the mobile phase is sent from the outside to the control section, the control section controls the liquid feeding section and the sample introduction section to switch the flow path switching valve and send it. The liquid part is connected to the sampling needle side, the sampling needle is moved from the injection port to the drain port, and the flow rate of the liquid feeding part is increased. The mobile phase is discharged from the liquid feeding unit to the outside of the apparatus at high speed via the flow path switching valve, the sampling loop, the sampling needle, and the drain port, and the flow path is filled or replaced with a desired mobile phase. Thereafter, the sampling needle is returned to the injection port, and the flow rate of the pump is returned to a low speed to feed the liquid, thereby completing the mobile phase filling or replacement of the entire flow path.
When cleaning the outside of the sampling needle, the control unit causes the sampling needle to enter the cleaning liquid stored in the cleaning port. A clean cleaning liquid is appropriately supplied to the cleaning port, and an excessive amount of cleaning liquid is discharged to the drain port.
[0011]
Examples of flow path switching valves in the sample introduction section include at least a position for connecting the liquid feed section to the column via the sampling loop, a position for connecting the liquid feed section directly to the column, and a liquid feed section connected to the sampling loop. In addition, the position is switched between the position where the upstream of the column is closed, and at the position where the liquid feeding part is directly connected to the column, the flow path connection is made so that the suction / discharge member is connected to the sampling loop.
[0012]
【Example】
FIG. 2 is a schematic flow path configuration diagram showing an embodiment.
From a pump unit (liquid feeding unit) 2 for feeding a mobile phase, an autoinjector (sample introduction unit) 4 for introducing a sample into a flow path, a column 6 for separating a sample, and a detection unit 8 for sequentially detecting the separated sample It is configured.
[0013]
The pump unit 2 includes a double plunger reciprocating liquid feeding pump 10 as an example. The suction side of the primary pump head 12 of the pump 10 is connected to the mobile phase container 16 in which the mobile phase is stored via the check valve 14a, and the secondary side pump head 18 is connected to the discharge side via the check valve 14b. Connected to the inhalation side. The discharge side of the secondary pump head 18 is connected to the auto injector 4 via a line filter 20 that removes foreign matters mixed in the mobile phase. A pressure sensor 22 is provided in the flow path between the secondary pump head 18 and the line filter 20.
[0014]
FIG. 3 is a schematic flow path configuration diagram showing the auto injector 4 in more detail.
The autoinjector 4 includes a high-pressure valve 26 and a low-pressure valve 28 to switch the flow path. The high-pressure valve 26 includes six ports (1) to (6) in the stator, and the rotor includes three flow channel grooves A, B, and C for switching the connection between these ports. Ports {circle around (1)} to {circle around (6)} are arranged on the circumference of the stator at equal intervals corresponding to 60 ° rotation of the rotor. The channel A is a channel for switching the port (1) to the port (2) or (6), and the channel (B) is changed from the port (3) to the port (2) or (4). The channel groove C is a channel groove for switching and connecting the port (5) to the port (4) or (6).
[0015]
Channel groove A is provided with a channel groove longer than the distance from port (1) to port (2) or from port (1) to port (6), and channel groove B is from port (2) to port (3) or A channel groove longer than the distance from port (3) to (4) is provided. That is, part of the channel grooves A and B is formed by extending the channel groove beyond the rotation of 60 °. For example, the length of the channel grooves A and B is 90 ° of rotation. is there. As a result, in addition to the two positions where the channel grooves A, B, and C each connect between the ports, as shown in the auto drain position of FIG. 1) can be connected to port (2) and port (3) can be connected to port (4) by channel groove B, while channel groove C can be connected between ports. It becomes a position valve.
[0016]
The stator of the low pressure valve 28 has four ports a to d, and the rotor has a position where the ports b and c are connected, and ports d and a as shown in FIGS. 6 and 9 described later. As shown in FIG. 8, which will be described later, a flow path groove is provided that can take three positions: a position where none of the ports are connected. Therefore, the low pressure valve 28 is also a three-position valve.
[0017]
The port {circle around (1)} of the high pressure valve 26 is connected to a flow path through which the mobile phase of the mobile phase container 16 is supplied by the pump unit 2. A sampling loop 24 is provided in the flow path connected to the port (2), and a sampling needle 36 is provided at the tip of the flow path. The sampling needle 36 can move between the injection port 32, the sample container 34, the drain port 38 and the washing port 46 (see FIG. 2). The flow path connected to the port (3) is connected to the port b of the low-pressure valve 28 via a metering pump (suction / discharge member) 30. The port {circle around (4)} is connected to the port a of the low-pressure valve 28 by a cleaning liquid flow path 42. An injection port 32 is connected to the port (5). An analysis flow path connected to the detection unit 8 through the column 6 is connected to the port (6).
[0018]
A cleaning port 46 is connected to the other port c of the low-pressure valve 28, and a rinse liquid (cleaning liquid) for cleaning the outside of the sampling needle 36 is supplied to the cleaning port 46. A drain port 38 is provided in the vicinity of the cleaning port 46. A flow path connected to the side wall of the drain port 38 is provided on the side wall of the cleaning port 46, and an excessive amount of rinse liquid overflows from the cleaning port 46 and is discharged to the drain port 38. The mobile phase can be discharged from the sampling needle 36 to the drain port 38. The rinse liquid and mobile phase are discharged from the drain port 38 to the outside. The flow path connected to the other port d is led to a cleaning liquid container 44 that stores a rinse liquid.
[0019]
Thin pipes are used in the flow path between the injection port 32 and the valve 26, the flow path between the valve 26 and the column 6, and the flow path between the column 6 and the detection unit 8 in order to prevent dilution of the sample.
In order to control the operation of the pump unit 2 and the autoinjector 4, a control unit 40 is provided.
[0020]
In this embodiment, the operation during analysis will be described. 3 to 7 show the sampling operation in the order of positions.
FIG. 3 shows the (A) Ready (under analysis) position, and the high pressure valve 26 is connected between ports (1) and (2) and between (5) and (6). The sent mobile phase passes through the sampling loop 24, passes through the connection point between the sampling needle 36 and the injection port 32, and flows through the flow path from the column 6 to the detection unit 8.
The low-pressure valve 28 is connected between the ports b and c, and the metering pump 30 is opened to the atmosphere via the cleaning port 46.
[0021]
FIG. 4 shows the (B) De-press (pressure release process) position. When the high pressure valve 26 is switched from the state shown in FIG. 3 and the ports (2) and (3) are connected, 24 is opened to the atmosphere from the metering pump 30 through the washing port 46, and the metering pump 30 is discharged in preparation for the next sample suction step. The rinse liquid overflowing from the cleaning port 46 by the discharge operation is discharged to the drain port 38. Further, the connection between the ports {circle around (1)} and {circle around (6)} of the high-pressure valve 26 allows the mobile phase to continue flowing through the flow path through the column 6 and the detection unit 8.
[0022]
FIG. 5 shows a (C) Load (sample inhalation) position. The low-pressure valve 28 is switched from the state shown in FIG. 4, and the port b connected to the metering pump 30 is closed. Then, the sampling needle 36 is immersed in the sample container 34 containing the sample, the metering pump 30 is inhaled, and the sample is sucked into the sampling loop 24 and collected. Thereafter, the sampling needle 36 is infiltrated into the rinse liquid stored in the cleaning port 46 and the outside of the sampling needle 36 is cleaned.
[0023]
FIG. 6 shows the (D) INJ / Purge in (sample injection / metering pump purge suction) position, the sampling needle 36 is returned to the injection port 32 from the state of FIG. 5, the high pressure valve 26 is switched, and the port ▲ 1 Between ▼ and (2) and between ports (5) and (6) are connected. As a result, the mobile phase passes through the sampling loop 24, passes through the connection point between the sampling needle 36 and the injection port 32, flows through the flow path from the column 6 to the detection unit 8, and the sample collected by the sampling loop 24 enters the column 6. The sample separation is started in column 6.
[0024]
Further, the high pressure valve 26 is also connected between the ports (3) and (4) in the state of FIG. The low pressure valve 28 is switched from the state shown in FIG. 5 to a state where the ports b and c are connected while the port a is closed. Then, the metering pump 30 is discharged, and the rinse liquid and the sample in the metering pump 30 are discharged to the cleaning port 46. Thereafter, the low-pressure valve 28 is switched again, and the ports a and d are connected as shown in FIG. 6. After the port b is closed, the metering pump 30 is inhaled and the cleaning liquid container 44 is discharged. The rinse liquid is sucked into the metering pump 30.
[0025]
FIG. 7 shows the (E) Purge out (measuring pump purge discharge) position. The low pressure valve 28 is switched from the state shown in FIG. 6 to connect the ports b and c, and the port a is closed. Then, the metering pump 30 is discharged, and the rinse liquid sucked into the metering pump 30 is supplied to the cleaning port 46 and the flow path of the metering pump 30 is cleaned. An excessive amount of rinse liquid is discharged through the drain port 38. The analysis is continued while the high pressure valve 26 remains in the state shown in FIG. 6, and the sample components separated by the column 6 are detected by the detection unit 8.
In this way, through the positions (A) → (B) → (C) → (D) → (E) in the order shown in FIG. 3 to FIG. 7, sampling into the sampling loop 24, column 6 A series of analysis operations of injection, separation and analysis are automatically performed. Then, after the rinse liquid is sucked into the metering pump 30 at the position (D), the low pressure valve 28 is switched to connect between the ports b and c, and the position (A) is returned. Here, it is preferable to repeat the positions (D) and (E) during the analysis to perform the purification operation of the metering pump 30 and sufficiently clean the cleaning port 46.
[0026]
In this embodiment, as another position, there is a (F) Auto Drain (automatic discharge) position shown in FIG.
In the Auto Drain position (F), only the ports (1) and (2) and the ports (3) and (4) of the high-pressure valve 26 are connected, and the sampling needle 36 is moved to the drain port 38. The other ports (5) and (6) of the high pressure valve 26 and all the ports of the low pressure valve 28 are closed. Then, the mobile phase is sent by the pump unit 2 and discharged from the high pressure valve 26 to the drain port 38 through the sampling loop 24. Since the drain port 38 and the washing port 46 are provided separately, the washing port 46 can be prevented from being contaminated by the mobile phase discharged from the sampling needle 36.
[0027]
The case where the entire flow path is filled with the mobile phase or the mobile phase is replaced using the Auto Drain position (F) will be described.
The switching of the high-pressure valve 26 and the low-pressure valve 28 and the movement of the sampling needle 36 are in the position (A) Ready → (B) De-press → (F) Auto Drain → (B) De-press → (A) Ready. To be controlled.
That is, initially, the position is at the Ready position (A) shown in FIG. 4 is switched to the Auto Drain position (F) shown in FIG. 8 via the De-press position (B) shown in FIG. In the Auto Drain position (F), the driving of the pump unit 2 is switched to high-speed driving, and the mobile phase is filled or replaced in a short time. After the mobile phase is filled or replaced, the mobile phone is returned to the Ready position (A) through the De-press position (B).
The analysis operation of this embodiment and the operation of filling or replacing the mobile phase are controlled by the control unit 40 shown in FIG.
According to the present invention, not only the drain valve motor is unnecessary, but also the drain valve itself is unnecessary. As a result, the introduction or replacement of the mobile phase can be automated without increasing the cost of the apparatus.
[0028]
In this embodiment, as another position, (G) Auto Drain / Purge in (automatic drain / purge inhalation) position shown in FIG. 9 and (H) Auto Drain / Purge out ( There is an automatic discharge / metering pump purge discharge) position.
At the position (G), the ports a and d of the low pressure valve 28 are connected and the port b is closed while the high pressure valve 26 is in the position (F). Then, the metering pump is inhaled, and the rinse liquid is sucked into the metering pump 30 from the cleaning liquid container 44.
At the position (H), the low pressure valve 28 is switched while the high pressure valve 26 is in the position (G), the port b and c are connected, and the port a is closed. Then, the metering pump 30 is discharged, and the rinse liquid sucked into the metering pump 30 is supplied to the cleaning port 46. An excessive amount of rinse liquid is discharged through the drain port 38.
By repeating the positions (G) and (H), the purification operation of the metering pump 30 can be automatically performed while filling or replacing the mobile phase of the pump unit 2.
[0029]
In the present invention, since the (F) Auto Drain position shown in FIG. 8 can be taken, the filling and replacement of the mobile phase can be automatically executed by a program. This means, for example, that the mobile phase replacement from the plurality of mobile phase vessels to the respective valves in gradient analysis is automatically executed by the program before the analysis start time, thereby shortening the analysis time. Will be able to. The next FIG. 11 is an example of such a gradient analysis.
[0030]
FIG. 11 is a schematic configuration diagram showing a part of another embodiment.
Mobile phase containers 43a, 43b, 43c each containing a mobile phase and a cleaning liquid container 43d containing a cleaning liquid are connected to the suction side of the primary pump head of the pump section via electromagnetic valves 45a, 45b, 45c, 45d, respectively. Has been.
Since the opening and closing of the solenoid valves 45a, 45b, 45c, and 45d can be controlled to select the mobile phase or the cleaning liquid, the mobile phase can be selected and replaced with only a button operation. It is also possible to automate the cleaning process.
If the (F) Auto Drain position is programmed according to the present invention, the replacement of the mobile phase from the mobile phase containers 43a to 43c to the respective electromagnetic valves 45a to 45c can be automated.
[0031]
In this embodiment, the mobile phase and the cleaning liquid are selected by opening and closing the electromagnetic valves 45a, 45b, 45c, and 45d. However, the present invention is not limited to this, and a liquid feed pump instead of the electromagnetic valve is used. The mobile phase and the cleaning liquid may be selected by driving the liquid feeding pump. In that case, the mobile phase replacement of the flow path from each mobile phase container to the mixer through each liquid feed pump can be automated by a program.
[0032]
FIG. 12 is a schematic configuration diagram showing still another embodiment. The same parts as those in FIG. 3 are denoted by the same reference numerals, and description thereof is omitted.
The stator of the low-pressure valve 48 has five ports a to e, and the rotor is in addition to the position where the ports b and c are connected, the position where the ports d and a are connected, and the position where none of the ports are connected. Thus, the position where the ports d and e are connected can be taken. A manual syringe 50 is connected to the port e.
When the rinsing liquid is filled in the flow path between the cleaning liquid container 44 and the port d, the rinsing liquid is cleaned by repeating the operation similar to the operation described in FIGS. 6 and 7 and repeating the suction and discharge of the metering pump 30. Although the flow path between the container 44 and the port d may be filled, it takes time to fill the rinse liquid. Therefore, in this embodiment, the low pressure valve 48 is switched to connect the ports d and e, and then the manual syringe 50 is inhaled to fill the flow path between the cleaning liquid container 44 and the port d with the rinse liquid. Thereby, the time taken to fill the rinse liquid can be shortened.
[0033]
【The invention's effect】
In the liquid chromatograph of the present invention, the drain port for discharging the liquid discharged from the sampling needle to the outside is provided , and the drain port and the cleaning port are provided separately. Can be prevented and the outside of the sampling needle, that is, the sample can be prevented from being contaminated with the mobile phase.
In addition, when the analysis is interrupted after the sample is sucked into the sampling loop, the sample in the sampling loop can be discharged to the drain port by the mobile phase, so that there is an effect that the return from the interrupted sequence is facilitated.
[Brief description of the drawings]
FIG. 1 is a schematic flow channel configuration diagram showing conventional HPLC.
FIG. 2 is a schematic flow path configuration diagram showing an embodiment.
FIG. 3 is a schematic flow path configuration diagram showing the embodiment in a ready position.
FIG. 4 is a schematic flow path configuration diagram showing the embodiment in a De-press position.
FIG. 5 is a schematic flow path configuration diagram showing the embodiment at a load position.
FIG. 6 is a schematic flow path configuration diagram showing the same example in an INJ / Purge in position.
FIG. 7 is a schematic flow path configuration diagram showing the embodiment at a purge out position.
FIG. 8 is a schematic flow path configuration diagram showing the embodiment at an Auto Drain position.
FIG. 9 is a schematic flow path configuration diagram showing the embodiment in an Auto Drain / Purge in position.
FIG. 10 is a schematic flow path configuration diagram showing the embodiment at an Auto Drain / Purge out position.
FIG. 11 is a schematic flow channel configuration diagram showing a mobile phase supply portion for gradient analysis of another embodiment.
FIG. 12 is a schematic flow path configuration diagram showing still another embodiment.
[Explanation of symbols]
2 Pump unit 4 Autoinjector 6 Column 8 Detection unit 10 Double plunger reciprocating feed pump 12 Primary pump head 16 Mobile phase vessel 18 Secondary pump head 20 Line filter 22 Pressure sensor 24 Sampling loop 26 High pressure valve 28 Low pressure Valve 30 Metering pump 32 Injection port 34 Sample container 36 Sampling needle 38 Drain port 40 Control unit 42 Flow path for cleaning liquid 44 Cleaning liquid container 46 Cleaning port

Claims (2)

Control and column for separating a sample, and a liquid supply unit for liquid feeding the mobile phase, a sample inlet, a detector for detecting the sample separated by the column, the operation of the liquid supply portion and the sample introducing portion In a liquid chromatograph equipped with a control unit for
Includes a drain port for discharging the liquid to the outside,
The sample introduction section includes a sample loop provided with a sampling needle at the tip for collecting the sample by sucking the sample from the container, an injection port into which the sample is injected by inserting the sampling needle, and a flow path switching valve.
The flow path switching valve is a position for connecting the liquid feeding section and the column, and the liquid feeding section is connected to the column via the sample loop and the injection port, and the sample collected from the sampling needle to the sample loop A first position for injecting the entire amount into the column, a second position for connecting the liquid feeding part to the column without passing through the sample loop and the injection port, and connecting the liquid feeding part to the sample loop. Take the third position to close the upstream,
When the flow path switching valve is in the third position, the control unit positions the sampling needle at the drain port and switches the driving of the liquid feeding unit to a higher speed driving than at the time of analysis. A liquid chromatograph characterized by that. The liquid chromatograph according to claim 1, further comprising a cleaning port that stores the supplied cleaning solution and discharges an excessive amount of the cleaning solution overflowing from the cleaning port to the drain port .

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