JP2001255315A - Liquid chromatograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the contamination of a washing port due to a mobile phase. SOLUTION: A high pressure valve 26 is changed over to connect the flow channel from a pump part 2 to a sampling needle 36 through a sampling loop 24 and the sampling needle 36 is moved to a drain port 38. A pump 10 is driven at a high speed to fill or replace the flow channel from the interior of the pump 10 to the sampling needle 36 with a desired mobile phase at a high speed. A low pressure valve 28 is changed over to connect a metering pump 30 to a washing liquid container 44 and a rinse liquid is sucked by the metering pump 30 and the valve 28 is changed over to connect the metering pump 30 to the washing port 46 and the rinse liquid is discharged from the metering pump 30 to be supplied to the washing port 46. The excess rinse liquid is discharged to the drain port 38.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field 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]

2. Description of the Related Art FIG. 1 is a schematic flow path diagram showing a conventional HPLC. The column 5 for separating the sample, the pump unit 1 for sending the mobile phase to the column 5, and the sample are collected from 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. Auto-injector 3 introduced into the mobile phase flow path upstream of
A detection unit 7 for detecting a sample separated by the column 5;
The control unit 41 is configured to control operations of the pump unit 1 and the auto injector 3.

The auto-injector 3 is provided with a two-position six-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 a 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 measuring 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.

After the sampling needle 39 sucks in the sample, a washing port 47 for supplying a washing liquid for washing the outside of the sampling needle 39 is provided. A cleaning liquid is appropriately supplied to the cleaning port 47, and an excessive amount of the cleaning liquid is discharged. Downstream of the column 5, a detection unit 7 for detecting the sample separated in the column 5 is connected. A thin tube is used for 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 to prevent dilution of the sample.

[0005] In this conventional example, when the entire flow path is filled with the mobile phase or the mobile phase is replaced when the apparatus is started, the inside of the pump section 1 has a relatively large volume.
If the mobile phase is flowed at a low speed as usual, it takes a considerable time to replace the mobile phase inside the pump. However, when the mobile phase flows at a high speed, the pressure after the injection port 35 including the column 5 increases because the piping is thin. Therefore, the mobile phase cannot flow at a high speed in the flow path after the injection port 35. Therefore, a drain valve is provided in the pump unit 1, the drain valve is switched to the drain side, and then the pump is driven at a high speed to introduce the mobile phase into the pump.

[0006]

Manually opening and closing the drain valve to fill or replace the mobile phase involves:
Since it 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 pressure is applied to the drain valve, so that a high-torque motor is required, 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 washing port 47, there is a possibility that the washing port 47 will be contaminated with the mobile phase. An object of the present invention is to prevent contamination of a cleaning port.

[0007]

The liquid chromatograph of the present invention comprises a column for separating a sample, a liquid sending section for sending a mobile phase to the column, and a suction / discharge member. A sample introduction unit that switches the flow path switching valve to introduce the collected sample into the mobile phase flow path upstream of the column, a detection unit that detects the sample separated by the column, a liquid sending unit, and a sample. What is claimed is: 1. A liquid chromatograph comprising a control unit for controlling an operation of an introduction unit, comprising: a drain port for discharging a liquid discharged from a sampling needle to the outside; and a drain port for storing a supplied cleaning liquid and discharging an excessive amount of the cleaning liquid. And a washing port for discharging to a washing machine.

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 separately provided, it is possible to prevent the cleaning port from being contaminated by the mobile phase. It is possible to prevent the outside of the sampling needle and thus the sample from being contaminated with the mobile phase.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In addition to controlling the analysis operation of each part, a control part switches a flow path switching valve to connect a liquid sending part to a sampling needle via a sampling loop and positions a sampling needle at a drain port. In addition, the operation of switching the driving of the liquid sending unit to the high-speed driving is controlled, and the operation of cleaning the outside of the sampling needle by injecting the sampling needle into the cleaning liquid stored in the cleaning port is also controlled.

When a signal for filling the flow path with the mobile phase or a signal for exchanging the mobile phase is sent from the outside to the control unit, the control unit controls the liquid sending unit and the sample introduction unit to operate the flow path switching valve. By switching, the liquid sending section 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 sending section is increased.
The mobile phase is discharged out of the apparatus at a high speed from the liquid sending unit 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 the cleaning liquid is discharged to the drain port.

Examples of the flow path switching valve in the sample introduction section include at least a position where the liquid sending section is connected to the column via a sampling loop, a position where the liquid sending section is directly connected to the column, and a sample where the liquid sending section is sampled. The position is switched between a position connected to the loop to close the upstream of the column, and a flow path connection is made so that the suction / discharge member is connected to the sampling loop at the position where the liquid sending section is directly connected to the column.

[0012]

FIG. 2 is a schematic flow diagram showing an embodiment of the present invention. A pump section (liquid sending section) 2 for sending a mobile phase, an auto injector (sample introducing section) 4 for introducing a sample into a flow path, a column 6 for separating a sample, and a detecting section 8 for sequentially detecting the separated sample. It is configured.

The pump section 2 is provided with a double plunger reciprocating liquid feed pump 10 as an example. The suction side of the primary pump head 12 of the pump 10 is connected via a check valve 14a to the mobile phase container 1 in which the mobile phase is stored.
The discharge side is connected to the suction side of the secondary side pump head 18 via a check valve 14b. 2
The discharge side of the secondary pump head 18 is connected to the auto injector 4 via a line filter 20 for removing foreign substances mixed in the mobile phase. Secondary pump head 18
A pressure sensor 22 is provided in the flow path between
Is provided.

FIG. 3 is a schematic flow diagram showing the auto injector 4 in more detail. Auto injector 4
Is provided with a high-pressure valve 26 and a low-pressure valve 28 to switch the flow path. The high pressure valve 26 has six ports on the stator, and the rotor has three flow grooves A, B,
C is provided. From the port, they are arranged on the circumference of the stator at equal intervals of 60 ° rotation of the rotor.
The flow channel A is a flow channel for switching the port to the port or the port for connection, the flow channel B is a flow channel for switching the port to the port or the connection, and the flow channel C is the port. Is a channel groove for switching and connecting to a port or a port.

The flow channel A has a flow channel that is longer than the distance from the port or from the port.
Has a channel groove that is longer than the distance from the port or from the port. That is, the flow grooves A and B
Is formed so that the flow channel extends beyond the rotation of 60 °, and the length of the flow channels A and B is, for example, 90 ° of rotation. As a result, in addition to the two positions where the flow grooves A, B, and C respectively connect the ports, as shown in the auto drain position in FIG. While the port is connected to the port by the flow channel B, the flow channel C can be in a state where the ports are not connected to each other, and the high-pressure valve 26 is a three-position valve.

The stator of the low-pressure valve 28 has four ports a to d, and its rotor has a position connecting the ports b and c, and ports d and a as shown in FIGS. 6 and 9 described later. And a flow path groove that can take three positions, that is, a position where no port is connected, as shown in FIG. 8 described later. Therefore, the low pressure valve 28 is also 3
It is a position valve.

The port of the high pressure valve 26 is connected to the pump 2
Is connected to the flow path of the mobile phase container 16 to which the mobile phase is supplied. A sampling loop 24 is provided in the flow path connected to the port, 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 is connected to the port b of the low-pressure valve 28 via a measuring pump (suction / discharge member) 30. The port is connected to a port a of the low-pressure valve 28 by a flow path 42 for a cleaning liquid. Injection port 3 on port
2 are connected. The port is connected to an analysis flow path connected to the detection unit 8 via the column 6.

A cleaning port 46 is connected to another 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. Drain port 3 near cleaning port 46
8 are provided. On the side wall of the cleaning port 46, a flow path leading to the side wall of the drain port 38 is provided.
An excessive amount of the rinsing 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 rinsing liquid and the mobile phase are discharged from the drain port 38 to the outside. The flow path connected to another port d is led to a cleaning liquid container 44 storing a rinsing liquid.

Injection port 32-valve 26
The flow path between the valve 26 and the flow path between the column 6 and the column 6
A thin tube is used in the flow path between the detection units 8 to prevent dilution of the sample. A control unit 40 is provided for controlling operations of the pump unit 2 and the auto injector 4.

In this embodiment, the operation at the time of analysis will be described. 3 to 7 show the sampling operation in order of position. FIG. 3 shows the (A) Ready (analyzing) position.
And the mobile phase sent out by the pump unit 2 passes through the sampling loop 24 and passes through the sampling needle 36 and the injection port 32.
Flows from the column 6 through the flow path passing through the detection unit 8 via the connection point of 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.

FIG. 4 shows a (B) De-press (depressurizing step) position, in which the high-pressure valve 26 is switched from the state shown in FIG.
The flow path containing the sample loop 24 is opened from the metering pump 30 to the atmosphere via the washing port 46, and the metering pump 30
Is discharged in preparation for the next sample suction step. The rinsing liquid overflowing from the cleaning port 46 by the discharge operation is discharged to the drain port 38. In addition, by being connected to the port of the high-pressure valve 26, the mobile phase continues to flow through the flow path passing through the column 6 and passing through the detection unit 8.

FIG. 5 shows the (C) Load (sample suction) 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 operated to suck, and the sample is sucked into the sampling loop 24 and collected. After that, the sampling needle 36 is immersed in the rinsing liquid stored in the cleaning port 46, and the outside of the sampling needle 36 is cleaned.

FIG. 6 shows a (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, and the high-pressure valve 26 is switched.
The connection with the port and the connection with the port are made. As a result, the mobile phase passes through the sampling loop 24, flows through the flow path from the column 6 through the connection point between the sampling needle 36 and the injection port 32, and passes through the detection unit 8, and the sample collected by the sampling loop 24 flows into the column 6. The sample is then separated in column 6.

The high pressure valve 26 is also connected to a port in the state shown in FIG. Then, the low pressure valve 28 is switched from the state of FIG. 5 to a state in which the port b and the port c are connected while the port a is closed. Then, the measuring pump 30 is caused to perform a discharging operation, and the rinsing liquid and the sample in the measuring pump 30 are discharged to the cleaning port 46. Thereafter, the low-pressure valve 28 is switched again to connect between the ports a and d as shown in FIG. 6, and after the port b is closed, the metering pump 30 is operated to suction and the cleaning liquid container 44 The rinsing liquid is sucked into the metering pump 30.

FIG. 7 shows an (E) Purge out (measurement 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 measuring pump 30 is caused to perform a discharging operation, and the rinsing liquid sucked into the measuring pump 30 is supplied to the cleaning port 46 and the measuring pump 30 is discharged.
Are cleaned. Excess rinsing liquid is drained through drain port 38. The analysis is continued while the high-pressure valve 26 remains in the state shown in FIG. 6, and the sample component separated in the column 6 is detected by the detection unit 8. Thus, the positions (A) → (B) →
By going through the states of (C) → (D) → (E), a series of analysis operations including sampling of the sample into the sampling loop 24, injection into the column 6, and separation / analysis are automatically performed.
Then, after the rinsing liquid is sucked into the metering pump 30 at the position (D), the low-pressure valve 28 is switched to connect the ports b and c, and returns to the position (A). Here, it is preferable that the cleaning operation of the metering pump 30 is performed by repeating the positions (D) and (E) during the analysis, and the cleaning of the cleaning port 46 is sufficiently performed.

In this embodiment, as another position, there is an (F) Auto Drain (automatic drain) position shown in FIG. In the Auto Drain position (F),
Only the connection to and from the port of the high pressure valve 26 is made, and the sampling needle 36 is moved to the drain port 38. The other ports of the high pressure valve 26 and all ports of the low pressure valve 28 are closed. The mobile phase is sent by the pump unit 2 and is discharged from the high-pressure valve 26 to the drain port 38 via the sampling loop 24. Since the drain port 38 and the cleaning port 46 are provided separately, it is possible to prevent the mobile port discharged from the sampling needle 36 from contaminating the cleaning port 46.

The case where the mobile phase is filled with the mobile phase or the mobile phase is replaced using the Auto Drain position (F) will be described. High pressure valve 26 and low pressure valve 2
8 and the movement of the sampling needle 36 are performed at the position (A) Ready → (B) De-press →
Control is performed so that (F) Auto Drain → (B) De-press → (A) Ready. That is, initially, the position is at the ready position (A) shown in FIG. Then, it 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 drive of the pump unit 2 is switched to high-speed drive, and the filling or replacement of the mobile phase is performed in a short time. After the filling or replacement of the mobile phase is completed, the mobile terminal returns to the ready position (A) via the de-press position (B). Both 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 is the motor for the drain valve 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 device.

In this embodiment, as other positions, (G) Auto Drain / Purge in (Automatic Drain / Purge in) position shown in FIG. 9 and FIG.
(H) Auto Drain / Purge out (automatic drain / metering pump purge discharge) position. In the position (G), the port a and the port d of the low-pressure valve 28 are connected while the high-pressure valve 26 is in the position (F), and the port b is closed. Then, the measuring pump is operated to suck, and the rinsing liquid is sucked into the measuring pump 30 from the cleaning liquid container 44. In the position (H), the low-pressure valve 28 is switched while the high-pressure valve 26 is in the state of the position (G) to connect the ports b and c, and the port a is closed. Then, the measuring pump 30 is caused to perform a discharging operation, and the rinsing liquid sucked into the measuring pump 30 is supplied to the cleaning port 46. Excess rinsing liquid is drained through drain port 38. By repeating the positions (G) and (H), the purifying operation of the metering pump 30 can be automatically performed while the mobile phase of the pump unit 2 is filled or replaced.

In the present invention, (F) Auto D shown in FIG.
Since the rain position can be taken, the filling and replacement of the mobile phase can be automatically executed by the program. This means that, for example, in the gradient analysis, the mobile phase of the flow path from the plurality of mobile phase containers to each valve is automatically replaced by a program by the analysis start time, thereby shortening the analysis time. Will be able to do it. FIG. 11 shows an example of such a gradient analysis.

FIG. 11 is a schematic configuration diagram showing a part of another embodiment. Mobile phase containers 43a and 43 each containing a mobile phase are provided on the suction side of the primary side pump head of the pump unit.
b, 43c and a cleaning liquid container 43d containing the cleaning liquid are connected via solenoid valves 45a, 45b, 45c, 45d, respectively. Solenoid valves 45a, 45b, 45c, 45
Since the mobile phase or washing solution can be selected by controlling the opening and closing of d, it is possible to select and replace the mobile phase with just a button operation, and to automate the flow channel washing process after analysis. become. If the (F) Auto Drain position is programmed according to the present invention, the mobile phase containers 43a to 43a-4
The replacement of the mobile phase from 3c to each of the solenoid valves 45a to 45c can be automated.

In this embodiment, the solenoid valves 45a, 45b, 4
The mobile phase and the cleaning liquid are selected by opening and closing the opening and closing of 5c and 45d. However, the present invention is not limited to this. The moving pump is provided with a liquid feeding pump instead of a solenoid valve. Selection of a phase and a washing solution may be performed. In that case, the mobile phase replacement of the flow path from each mobile phase container to the mixer via each liquid sending pump can be automated by a program.

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 will be omitted. The stator of the low pressure valve 48 has five ports ae, the rotor of which is connected to the ports b and c described above.
, A position where ports d and a are connected, a position where none of the ports are connected, and a position where ports d and e are connected. A manual syringe 50 is connected to the port e. When the flow path between the cleaning liquid container 44 and the port d is filled with the rinsing liquid, the same operation as that described with reference to FIGS. The flow path between the container 44 and the port d may be filled, but in this method, it takes time to fill the rinsing 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 operated to suction to fill the flow path between the cleaning liquid container 44 and the port d with the rinsing liquid. This allows
The time required to fill the rinsing liquid can be reduced.

[0033]

According to the liquid chromatograph of the present invention, a drain port for discharging the liquid discharged from the sampling needle to the outside and a cleaning port for storing the supplied cleaning liquid and discharging an excessive amount of the cleaning liquid to the drain port are further provided. Since the drain port and the washing port are separately provided, it is possible to prevent the washing port from being contaminated by the mobile phase discharged from the sampling needle,
It is possible to prevent the outside of the sampling needle and thus the sample 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 it is easy to return from the interrupted sequence.

[Brief description of the drawings]

FIG. 1 is a schematic flow path configuration diagram showing a conventional HPLC.

FIG. 2 is a schematic flow path configuration diagram showing one embodiment.

FIG. 3 is a schematic flow path configuration diagram showing the same embodiment in a ready position.

FIG. 4 is a schematic flow path configuration diagram showing the same embodiment in a De-press position.

FIG. 5 is a schematic flow path configuration diagram showing the same embodiment in a Load position.

FIG. 6 is a schematic flow path configuration diagram showing the same embodiment at an INJ / Purge in position.

FIG. 7 is a schematic flow path configuration diagram showing the same embodiment in a Purge out position.

FIG. 8 is a schematic channel configuration diagram showing the same embodiment in an Auto Drain position.

FIG. 9 is a schematic flow path configuration diagram showing the same embodiment in an Auto Drain / Purge in position.

FIG. 10 is a schematic flow diagram showing the same embodiment in an Auto Drain / Purge out position.

FIG. 11 is a schematic flow path configuration diagram showing a mobile phase supply part for gradient analysis according to another embodiment.

FIG. 12 is a schematic flow path configuration diagram showing still another embodiment.

[Explanation of symbols]

 2 Pump unit 4 Auto injector 6 Column 8 Detecting unit 10 Double plunger reciprocating liquid feed pump 12 Primary pump head 16 Mobile phase container 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 (3)

[Claims] A sample is collected from a sampling needle to a sampling loop, comprising a column for separating a sample, a liquid sending section for sending a mobile phase to the column, and a suction / discharge member. A sample introduction unit that switches a switching valve and introduces the mobile phase flow path upstream of the column,
In a liquid chromatograph including a detection unit that detects a sample separated by the column, and a control unit that controls operations of the liquid sending unit and the sample introduction unit, a liquid discharged from the sampling needle is externally provided. A liquid chromatograph comprising: a drain port for discharging; and a cleaning port for storing a supplied cleaning liquid and discharging an excessive amount of the cleaning liquid to the drain port. 2. The control unit, in addition to controlling the analysis operation by each unit, switches the flow path switching valve to connect the liquid sending unit to the sampling needle via the sampling loop, Is positioned at the drain port, the operation of switching the driving of the liquid sending section to high-speed driving is also controlled, and the sampling needle is immersed in the cleaning liquid stored in the cleaning port to clean the outside of the sampling needle. The liquid chromatograph according to claim 1, wherein the operation of the liquid chromatograph is also controlled. 3. A flow path switching valve of the sample introduction unit, wherein at least a position connecting the liquid sending unit to the column via the sampling loop, a position connecting the liquid sending unit directly to the column, The liquid sending unit is connected to the sampling loop and switched between a position to close the upstream of the column, and the position where the liquid sending unit is directly connected to the column is connected to the sampling and discharging member. The liquid chromatograph according to claim 1, wherein the liquid chromatograph is connected to the liquid chromatograph in such a manner as to be described above.