JP5223685B2 - Mobile phase supply device and liquid chromatograph using the mobile phase supply device - Google Patents

Description

  The present invention relates to a gradient-type mobile phase supply device that supplies a mobile phase composition while changing the mixing ratio of a plurality of mobile phases, and a liquid that performs separation analysis of a sample using such a mobile phase supply device. It relates to a chromatograph.

Conventionally, various devices for supplying a mobile phase to an analysis flow path of a liquid chromatograph have been proposed (see, for example, Patent Document 1). FIG. 4 schematically shows an example of a general mobile phase supply apparatus.
The mobile phase supply apparatus shown here includes mobile phase supply units 6a and 6b that supply two types of mobile phases 8a and 8b of different types. The mobile phase supply units 6a and 6b are controlled to supply and stop the mobile phases 8a and 8b by opening and closing the electromagnetic valves 12a and 12b. The flow path 3a through which the mobile phase 8a from the mobile phase supply section 6a flows and the flow path 3b through which the mobile phase 8b from the mobile phase supply section 6b flow join at the junction 17. The mixing channel 26 on the downstream side of the junction 17 is connected to the inlet 16 of the pump head 2 of the liquid feed pump via an inlet side check valve 28. An outlet flow path 20 is connected to the outlet 18 of the pump head 2 via an outlet-side check valve 19.

  In this mobile phase supply device, the mobile phase 8a or 8b is sucked into the pump chamber 2a by retreating the plunger 4 of the plunger pump, and the mobile phase comprising the mixed liquid of the mobile phases 8a and 8b by the advance of the plunger 4. Is fed to the outlet-side flow path 20. The electromagnetic valves 12a and 12b provided on the outlet sides of the mobile phase supply units 6a and 6b can be opened and closed at an arbitrary timing while synchronizing with the operation of the plunger pump. That is, the volume ratio of the mobile phases 8a and 8b sucked into the pump chamber 2a is adjusted by adjusting the ratio of the opening times of the electromagnetic valves 12a and 12b while the plunger 4 is retracted, and the pump chamber 2a The composition of the mobile phase that is fed to the outlet side flow path 20 side is determined. In this example, a liquid mixture of two types of mobile phases 8a and 8b is sent as a mobile phase. However, a mixture of a plurality of types of mobile phases can also be sent.

JP 2006-266975 A

  In liquid chromatographs, a mixture of a buffer solution in which a salt is dissolved and an organic solvent is often used as the mobile phase, and the ratio of the organic solvent is high when a buffer solution having a high salt concentration and the organic solvent are mixed. And salt may precipitate.

  In the example of FIG. 4, when the mobile phases 8a and 8b are respectively a buffer solution and an organic solvent having a high salt concentration, when the solenoid valves 12a and 12b are alternately switched in a short time, one mobile phase is the other. Since the mobile phase supplied before diffusing to the mobile phase side is switched, even if these mobile phases are mixed and salt is precipitated, it is in the vicinity of the junction 17. However, when the interval between the switching times of the electromagnetic valves 12a and 12b becomes larger, the mobile phase being supplied spreads to the flow path on the other mobile phase supply unit side where no liquid is supplied, There is a possibility that the salt reaches to the vicinity and precipitates there. When salt is deposited in the vicinity of the solenoid valve, when the solenoid valve is next opened, the salt may flow backward due to the movement of the valve body and enter the solenoid valve.

  In liquid chromatographs, various liquids such as acids, alkalis, and organic solvents are used as mobile phases. Therefore, members made of a fluororesin such as PTFE having excellent chemical resistance at the wetted parts as the electromagnetic valves 12a and 12b. The diaphragm valve comprised by is often used. If salt enters while the diaphragm valve is open, it will bite the salt between the valve body diaphragm and the valve seat valve body when it is closed, causing damage to the diaphragm and valve body that are softer than salt. There was a problem of being stuck. If the diaphragm or the valve body is damaged, even if the valve is closed, the liquid leaks from the damaged area, and the composition of the mobile phase fed from the pump chamber 2a cannot be accurately controlled.

  Therefore, an object of the present invention is to prevent salt from entering a solenoid valve that controls supply / stop of a mobile phase from each mobile phase supply unit.

  The mobile phase supply device of the present invention discharges a mobile phase from a plunger that reciprocates in a certain direction, a pump chamber that slides the plunger inside, a pump inlet for sucking the mobile phase into the pump chamber, and a pump chamber. Mobile phase supply connected to the pump inlet via a confluence, with a pump head having a pump outlet and an open / close valve provided on the outlet side controlling the supply and stop of the mobile phase to the pump chamber And a backflow prevention valve for preventing backflow of the mobile phase provided between the on-off valve of each mobile phase supply unit and the junction.

  According to the above configuration, on the flow path from the opening / closing valve of each mobile phase supply unit to the pump inlet, upstream of the confluence of the flow paths, the mobile phase from the confluence point to the mobile phase supply unit side Since a backflow prevention valve is provided to prevent backflow, the backflow prevention valve can block the spreading of the mobile phase in contact with the other mobile phase from the backflow prevention valve. Also, salt can be prevented from being deposited in the vicinity of the on-off valve on the upstream side.

  By the way, at the junction where the flow paths from the respective mobile phase supply units merge, different types of mobile phases are always in contact with each other, and the mobile phase being sent is filled with the mobile phase being stopped. If the diffusion is carried out into the flow path and the distance of the flow path is long, the diffusion distance of the mobile phase during liquid feeding becomes longer as the mobile phase supply time from the same mobile phase supply unit becomes longer. In order to supply all the mobile phases sent from the mobile phase supply unit to the pump chamber, it is necessary to supply all the mobile phases on the flow path side where the mobile phase has diffused to the pump chamber. Since it takes time to move all the mobile phases in the flow path to the pump chamber, it takes a long time to adjust the mobile phase in the pump chamber to a desired composition (concentration). In liquid chromatographs, sample components may be separated while changing the composition of the mobile phase, but in this case, the follow-up of the change in the composition of the mobile phase is delayed, and there is a problem that the analysis time becomes longer. .

  In the present invention, since the backflow prevention valve is provided between the on-off valve and the junction of each mobile phase supply unit, the diffusion of the mobile phase during liquid feeding is blocked by the backflow prevention valve. There is also an effect of shortening. Furthermore, the diffusion distance of the mobile phase can be further shortened by providing each backflow prevention valve as close to the junction as possible.

  A liquid chromatograph of the present invention includes the above mobile phase supply device, an analysis flow channel connected to a pump outlet of the mobile phase supply device, an injection port for injecting a sample into the analysis flow channel, an analysis flow A separation column that is provided on the downstream side of the injection port on the road and separates the sample into components, and a detector that is provided further on the downstream side than the separation column on the analysis flow path and detects the components separated by the separation column. And.

  In the mobile phase supply device of the present invention, a plurality of mobile phase supply units are connected to a pump inlet of a liquid feed pump composed of a plunger and a pump head via a junction, and an opening / closing valve of each mobile phase supply unit and a junction point A backflow prevention valve is installed in between to prevent backflow of the mobile phase, preventing backflow due to diffusion of the mobile phase being supplied to the pump chamber from the confluence to the mobile phase supply section. It can be stopped by a valve, and salt can be prevented from depositing in the vicinity of the on-off valve of the mobile phase supply unit. As a result, no salt enters the on-off valve due to the deposited salt, so that the valve body and valve seat of the on-off valve can be prevented from being damaged, and a system for controlling the supply and stop of the mobile phase by the on-off valve is maintained. be able to.

It is a schematic block diagram which shows the reference example of a mobile phase supply apparatus. It is a schematic block diagram which shows one Example of a mobile phase supply apparatus. It is a flow path figure showing roughly one example of a liquid chromatograph of a low-pressure gradient system. It is a schematic block diagram which shows an example of the conventional mobile phase supply apparatus.

A basic configuration of the mobile phase supply apparatus will be described with reference to FIG. FIG. 1 is a schematic configuration diagram showing a reference example of a mobile phase supply apparatus.
The mobile phase supply device 1 of this reference example mixes two types of mobile phases 8a and 8b in a pump chamber 2a of a liquid feed pump 5 so as to have a predetermined composition (concentration), and uses the mixed solution as a mobile phase. The liquid is supplied to the analysis flow path of the liquid chromatograph. The pump chamber 2 a is provided in the pump head 2. A plunger 4 is inserted into the pump head 2 from the tip, and the base end of the plunger 4 is always pushed toward the cam 24 by an elastic member such as a spring, thereby following the peripheral surface of the cam 24. The cam 24 is rotationally driven by the motor 22, and the distal end portion of the plunger 4 slides in the pump head 2 in a certain direction by the rotation of the cam 24.

  The pump head 2 is provided with a pump inlet 16 and a pump outlet 18 leading to the pump chamber 2a. The pump inlet 16 also serves as a junction where the two mobile phase supply channels 3a and 3b merge. The pump outlet 18 is provided with an outlet-side check valve 19 that is opened only when the mobile phase is fed from the pump chamber 2a, and an outlet channel 20 serving as an analysis channel for a liquid chromatograph is provided via the on-off valve 19, for example. It is connected.

  The mobile phase supply flow path 3a is a flow path for supplying the mobile phase 8a supplied by the mobile phase supply unit 6a to the pump chamber 2a. The mobile phase supply flow path 3b is a flow path for supplying the mobile phase 8b supplied by the mobile phase supply unit 6b to the pump chamber 2a. The mobile phase supply unit 6a includes a storage tank in which the mobile phase 8a is stored, a deaeration device 10a, and a solenoid valve (open / close valve) 12a, and supply and stop of supply of the mobile phase 8a are controlled by opening and closing the solenoid valve 12a. . Similarly, the mobile phase supply unit 6b includes a storage tank in which the mobile phase 8b is stored, a deaeration device 10b, and an electromagnetic valve (open / close valve) 12b, and the supply and stop of supply of the mobile phase 8b are controlled by opening and closing the electromagnetic valve 12b. Has been. The opening and closing of the solenoid valves 12a and 12b is controlled to synchronize with the operation of the plunger 4 by a control device (not shown). The electromagnetic valves 12a and 12b are, for example, diaphragm valves.

  A backflow prevention valve 14a is provided in the vicinity of the pump inlet 16 on the mobile phase supply flow path 3a, and a backflow prevention valve 14b is provided in the vicinity of the pump inlet 16 on the mobile phase supply flow path 3b. The backflow prevention valve 14a allows the liquid to flow in the direction from the mobile phase supply unit 6a to the pump inlet 16, but does not flow the reverse direction. That is, the backflow prevention valve 14a opens the valve and flows the mobile phase 8a only when supplying the mobile phase 8a from the mobile phase supply unit 6a to the pump chamber 2a, and stops the mobile phase supply of the mobile phase supply unit 6a. When the valve is closed, the liquid is prevented from flowing into the mobile phase supply unit 6a. The reverse flow prevention valve 14b is the same, and only when supplying the mobile phase 8b from the mobile phase supply unit 6b to the pump chamber 2a, the valve is opened to flow the mobile phase 8b, and the mobile phase supply of the mobile phase supply unit 6b is stopped. When it is, the valve is closed to prevent liquid from flowing into the mobile phase supply unit 6b.

The operation of the mobile phase supply device 1 will be described.
When the plunger 4 of the liquid feed pump 5 moves backward (moves to the right in the figure), either or both of the electromagnetic valves 12a and 12b are opened, and either or both of the mobile phases 8a and 8b are in the mobile phase supply flow. It is sucked and mixed into the pump chamber 2a through the passages 3a and 3b. At this time, the outlet side check valve 19 is closed to prevent the backflow of the liquid from the outlet side flow path 20.

  Since the composition of the mobile phase in the pump chamber 2a (mixing ratio of the mobile phases 8a and 8b) is determined by the opening time of the solenoid valves 12a and 12b while the plunger 4 is retracting, the mobile phase determined by the analysis The opening time of each solenoid valve 12a, 12b is controlled according to the composition.

  When sucking only the mobile phase 8a into the pump chamber 2a, a pressure difference is generated between the pump chamber 2a side and the container side of the mobile phase 8a by opening the electromagnetic valve 12a, thereby opening the backflow prevention valve 14a and releasing it. The mobile phase 8a deaerated by the gas device 10a is sucked into the pump chamber 2a. At this time, since the electromagnetic valve 12b is closed, the backflow prevention valve 14b is not opened, and the liquid on the pump inlet 16 side does not flow to the mobile phase supply unit 6b side than the backflow prevention valve 14b. The same applies to the case where only the mobile phase 8b is sucked into the pump chamber 2a. At this time, since the electromagnetic valve 12a is closed, the backflow prevention valve 14a is not opened, and the pump inlet 16 side is closer to the backflow prevention valve 14a. The liquid does not flow to the mobile phase supply unit 6a side.

  The mixed liquid of the mobile phases 8a and 8b sucked into the pump chamber 2a in this way opens the outlet side check valve 19 by the plunger 4 moving forward (moving to the left in the figure), and the outlet channel. 20 is fed.

In the mobile phase supply device 1 of this reference example , since the backflow prevention valves 14a and 14b are provided on the downstream side of the mobile phase supply flow paths 3a and 3b, one of the electromagnetic valves 12a and 12b is opened and the other is closed. Even when the mobile phase is closed, the mobile phase does not flow into the closed solenoid valve. For example, when the mobile phase 8a is sent as a buffer solution in which a salt is dissolved and the mobile phase 8b is sent as an organic solvent, the mobile phase supply channel 3a is always filled with a buffer solution and the mobile phase supply channel 3b is filled with an organic solvent. When the suction time of only the buffer solution becomes longer, the buffer solution may diffuse into the mobile phase supply channel 3b, and salt may precipitate in the mobile phase supply channel 3b. However, since the backflow prevention valve 14b is closed, the buffer solution cannot further diffuse to the mobile phase supply unit 6b side, and the place where the salt can precipitate is from the backflow prevention valve 14b to the pump inlet 16. Limited during. Therefore, salt does not precipitate in the vicinity of the electromagnetic valve 12b, and salt can be prevented from entering the electromagnetic valve 12b.

  Further, since the backflow prevention valves 14a and 14b are provided in the vicinity of the mobile phase supply flow path pump inlet 16, the diffusion of the mobile phase during the liquid transfer from the pump inlet 16 to the backflow prevention valves 14a and 14b. Since it is limited to a short section, the dead volume is reduced. Therefore, the time until all of the mobile phase to be sucked into the pump chamber 2a is sucked is shortened, and the followability of the composition of the mobile phase in the pump chamber 2a is improved.

In the above reference example , the mobile phase supply channels 3a and 3b are directly connected to the pump inlet 16. However, due to the structure of the pump head 2, the mobile phase supply channels 3a and 3b are pumped. When it cannot be directly connected to the inlet 16, as shown in FIG. 2, the mobile phase supply channels 3a and 3b are merged at another junction 17 and the downstream mixing channel 26 is pumped. A structure connecting to the inlet 16 is conceivable. In the mobile phase supply apparatus 1a shown in FIG. 2, the backflow prevention valves 14a and 14b are provided in the vicinity of the junction 17 to prevent the backflow and diffusion of the mobile phase toward the mobile phase supply units 6a and 6b. . In this example, an inlet-side check valve 28 is provided at the pump inlet 16, and the mobile phase in the pump chamber 2 a flows backward to the mixing channel 26 side when liquid is fed from the pump chamber 2 a to the outlet channel 20 side. To prevent that. This structure can be configured only by changing the portion upstream of the inlet side check valve 28 of the conventional mobile phase supply apparatus shown in FIG. 4, and the conventional liquid feed pump can be used as it is.

  In FIG. 1 and FIG. 2, as the backflow prevention valves 14a and 14b, the outlet side check valve 19, and the inlet side check valve 28, spherical valve bodies are valved by utilizing the pressure difference between the upstream and downstream of the valve mechanism. The type of the mechanism for closing the hole in the seat is shown, but the structure of the valve mechanism is not limited to this, and an elastic member such as a spring for more securely seating the valve body on the valve seat when closing the valve In addition to those incorporating a valve, a valve such as a solenoid valve may be forcibly closed. If a valve mechanism incorporating an elastic member that securely seats the valve body is used, it is not necessary to set the inlet side of the valve mechanism downward and the outlet side upward in consideration of the gravity direction of the valve body. A degree of freedom can be provided in the arrangement direction.

  Further, in the above-described embodiment of the mobile phase supply apparatus, a description has been given of a system in which two types of mobile phases are mixed and fed in the pump chamber 2a, but the present invention is not limited to this. Three or more mobile phase supply units may be arranged so as to mix three or more types of mobile phases, and these may be connected to the pump head 2.

Figure 3 is a flow path diagram schematically showing a liquid chromatograph of the low pressure gradient method with a mobile phase feeder 1,1a shown above, those of them equipped with a mobile phase supplying device 1a is a liquid chromatograph This is an example .
An analysis flow path 20 is connected to the outlet side of the liquid feed pump 5 of the mobile phase supply devices 1 and 1a. An injection port 30 for injecting a sample is provided on the analysis flow path 20, and a separation column 32 for separating the sample and a detector 34 for detecting the separated components are further provided downstream thereof. Yes. The mobile phase flowing through the analysis flow path 20 is supplied while being adjusted by the mobile phase supply device 1 or 1a so as to correspond to the component detected by the detector 34.

DESCRIPTION OF SYMBOLS 1,1a Mobile phase supply apparatus 2 Pump head 3a, 3b Mobile phase supply flow path 4 Plunger 5 Liquid feed pump 6a, 6b Mobile phase supply part 8a, 8b Mobile phase 10a, 10b Deaerator 12a, 12b Electromagnetic valve 14a, 14b Backflow prevention valve 16 Pump inlet 17 Junction point 18 Pump outlet 19 Outlet side check valve 20 Outlet flow path 22 Motor 24 Cam 26 Mixing flow path 28 Inlet side check valve 30 Injection port 32 Separation column 34 Detector

Claims (2)

A plunger that reciprocates in a fixed direction;
A pump chamber having a pump chamber for sliding the plunger therein, a pump inlet for sucking a mobile phase into the pump chamber, and a pump outlet for discharging the mobile phase from the pump chamber;
The supply and stop of the mobile phase to the pump chamber are controlled by open / close valves each provided on the outlet side, and a mobile phase supply unit connected to the pump inlet via a junction,
A backflow prevention valve for preventing backflow of the mobile phase provided between the on-off valve and the junction of each mobile phase supply unit;
A pump inlet side backflow prevention valve provided between the confluence and the pump inlet;
A mobile phase supply device comprising: The mobile phase supply device according to claim 1,
An analysis channel connected to a pump outlet of the mobile phase supply device;
An injection port for injecting a sample into the analysis flow path;
A separation column that is provided downstream of the injection port on the analysis flow path and separates the sample into components;
A liquid chromatograph comprising a detector that is provided further downstream than the separation column on the analysis flow path and detects components separated by the separation column.

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