JP2003107064A - High performance liquid chromatograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high performance liquid chromatograph that has a liquid- feeding system that is compact, is less expensive, and is capable of an energy- saving type two-liquid switching feed. SOLUTION: The liquid-feeding system of the high performance liquid chromatograph comprises a pump 1 for sucking and discharging liquid by reciprocating movement in a plunger 12 and the first and second supply source channels 4a and 4b of the mobile phase liquid body in the liquid-feeding system of the high performance liquid chromatograph, at the same time a valve 3 to switch a first state where the opening of the pump 1 is connected to the supply source channel 4a of the first liquid, a second state where the opening of the pump 1 is connected to the supply source channel 4b in the second liquid, and a third state where the opening of the pump 1 is connected to a liquid feed destination channel 5 as an intermediate state of the first and second states, thus synchronizing the valve 3 to the suction/discharge operation of the pump 1, and thus eliminating the need for equipping another solenoid valve or the like for switching the mobile phase liquid.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-performance liquid chromatograph, and more particularly to a high-performance liquid chromatograph capable of switching mobile phase liquids from two sources and sending the liquid. About graphs. [0002] In high performance liquid chromatography, when the analysis conditions are changed, it is often necessary to change the mobile phase. Further, when the analysis is continued with the same mobile phase, the mobile phase may be switched to the same type of mobile phase in another container in order to replenish the consumed mobile phase. To cope with such a case, a liquid feeding system capable of automatically switching the mobile phase is used. FIG. 3 shows, as an example, a basic configuration (single syringe) of a conventional liquid feeding system capable of switching between two liquids. In the figure, a pump 1 has a plunger drive mechanism 20.
The plunger 12 driven by the pump reciprocates in the pump chamber 11 to perform a suction / discharge operation through the port 15 of the pump 1, and is a type of pump generally called a syringe pump or a plunger pump.
The flow path switching valve (hereinafter simply abbreviated as a valve) 3
A valve drive mechanism 30 rotates a rotor (not particularly shown) having a communication groove 31 that connects two adjacent ports a, c, and d arranged at intervals of, for example, 60 degrees on the arc by a predetermined angle. This is a rotary valve that switches and connects the port 15 of the pump 1 to either the supply source flow path 4 or the liquid supply destination flow path 5. The liquid transfer destination flow path 5 is a flow path connected to a sample introduction unit (not shown), a column, a detector, and the like. The two types of mobile phase liquids A and B (hereinafter, referred to as liquid A and liquid B) to be sent are respectively solenoid valves 42a and 42b.
2b, it is connected to the port 15 of the pump 1 via the communication groove 31 between the supply flow path 4 and the valve 3. The two solenoid valves 42a and 42b are controlled by the control unit 10 so that only one of them is opened, and selects one of the liquid A and the liquid B as a liquid supply target. Now, the solenoid valve 42a is open and the solenoid valve 42b is closed, and the valve 3 is in the state shown in FIG.
When the plunger 12 is retracted (moved downward in the figure) in a state where the spaces are communicated, the liquid A is sucked into the pump chamber 11 through the supply source flow path 4. Next, the plunger 12 is pushed out (moved upward in the figure) after the valve 3 is moved by a predetermined angle to bring the ports d and c into communication.
And the liquid in the pump chamber 11 is pushed out, and the liquid
Flows to By repeating the above process, the solution A is continuously sent. When the solenoid valve 42a is closed and the solenoid valve 42b is opened, the liquid B can be sent in the same manner. As described above, in such a liquid feeding system, the port 15 of the pump 1 is connected to the supply flow path 4 during the suction operation of the pump 1, and the port 15 of the pump 1 is connected to the liquid supply destination during the discharging operation. The flow path is switched by the valve 3 so as to be connected to the flow path 5, whereby a flow of the liquid in one direction (from the supply source flow path 4 to the liquid transfer destination flow path 5) is formed. That is, the valve 3 has a rectifying function, and can be replaced by a check valve in principle. Further, since the pump 1 and the valve 3 need to be driven synchronously, the plunger drive mechanism 20 and the valve drive mechanism 30 are controlled by the common control unit 10. In the above operation process, port d is set to port a as an intermediate state of switching from suction to discharge or vice versa.
Also, there is a state in which communication is not performed with either of c and c. In order to alleviate a shock caused by a sudden change in pressure at the time of switching, the valve 3 is temporarily stopped in this state, that is, in a state where the valve 3 is turned 30 degrees counterclockwise from the state shown in FIG. Usually, a step of pressurizing or depressurizing the internal pressure in accordance with the pressure of the flow path (the supply source flow path 4 or the liquid transfer destination flow path 5) to be connected immediately thereafter is inserted. However, since these steps are not directly necessary for describing the present invention, description thereof will be omitted below because they are naturally included in the operation steps of the system. FIG. 3 shows an example in which a syringe pump having only one port 15 (single port syringe pump) is used. In a general syringe pump, a suction port and a discharge port are used in consideration of replacement of the liquid in the pump chamber. May be provided separately. FIG. 4 shows an example of a conventional liquid feed pump system using such a syringe pump having two ports. In the figure, components that are functionally the same as those in FIG. 3 are given the same numbers, and will not be described again. Also, the solenoid valves 42a and 42b, the plunger drive mechanism 2 not shown in FIG.
0, the valve driving mechanism 30, the control unit 10, and the like are provided similarly to FIG. The difference from FIG. 3 is that
Pump 1 has two ports (discharge port 13 and suction port 14)
Correspondingly, the number of required ports and the number of communication grooves of the valve 3 are each increased by one, but the overall operation is exactly the same as that shown in FIG. Although the valve 3 does not need to have the port indicated by the dotted line in the figure, if it does, it is closed with a plug. [0008] As described above, the use of a solenoid valve allows automatic switching between two fluids to be conventionally performed, but the apparatus is increased in size due to the provision of the solenoid valve. However, there is a problem that the cost increases and the power consumption also increases. The present invention has been made in view of such circumstances, and is more compact and lower cost than before.
It is another object of the present invention to provide an energy-saving liquid chromatograph provided with a liquid transfer system capable of switching and transferring two liquids. SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a rectifying flow path switching valve which operates in synchronization with a pump in a liquid feeding system of a liquid chromatograph. It is devised to also have a function. That is, the apparatus of the present invention includes a pump for sucking and discharging a liquid by reciprocating movement of a plunger, and first and second liquid supply source flow paths, and a port of the pump is connected to the first liquid supply source flow path. The first state, the second state in which the port of the pump is connected to the supply path of the second liquid, and the port of the pump as the intermediate state between the first and second states. A liquid supply system configured to include a flow path switching valve for switching between a third state connected to the liquid supply destination flow path and switching the flow path switching valve in synchronization with the suction / discharge operation of the pump; It is a high performance liquid chromatograph. This eliminates the need to separately provide an electromagnetic valve or the like for switching the mobile phase liquid. FIG. 1 shows an embodiment of the present invention. In the figure, a valve 3 is a rotary valve having six ports a to f arranged at intervals of 60 degrees on a circumference, and a communication groove 31 can communicate two adjacent ones of these ports. The liquids A and B to be fed are connected to the ports a and b of the valve 3 through the supply source flow paths 4a and 4b, respectively. The pump 1 is of a type having a discharge port 13 and a suction port 14 similar to those shown in FIG. 4, and the discharge port 13 is connected to a connection point p connecting ports d and f of the valve 3. , The suction port 14 is connected to the port e. The plunger 12 is driven by the plunger drive mechanism 20 and reciprocates to perform a suction / discharge operation (the upper and lower turning points in the reciprocating movement are respectively referred to as a top dead center and a bottom dead center). In addition, since the components denoted by the same reference numerals in FIG. 3 as those in FIG. 3 have been described above,
The description will not be repeated. The liquid feeding system shown in FIG. 1 operates as follows. (1) In the illustrated state, that is, in the state in which the ports a and e communicate with each other, the pump 1 is in a suction stroke, and as the plunger 12 descends from the top dead center, the liquid A passes through the supply flow path 4a and the pump chamber 11 Inhaled into. (2) After the plunger 12 has reached the bottom dead center, the valve 3 is rotated clockwise by 120 degrees to establish a state where the ports cf communicate with each other. In this state, the pump 1 is in the discharge stroke, and the liquid A in the pump chamber 11 is pushed out as the plunger 12 rises from the bottom dead center, and is supplied from the discharge port 13 to the liquid supply destination flow path 5. (3) After the plunger 12 reaches the top dead center, the valve 3 is rotated 120 degrees counterclockwise to the state of (1), and thereafter, the liquid A is obtained by repeating (1) to (3). The liquid is continuously sent. (4) When the mobile phase is switched to the liquid B, the valve 3 is rotated by 180 degrees (in either direction) after the plunger 12 reaches the top dead center after the end of the state of (2) above.
It is assumed that the ports be communicate with each other. Thereafter, the liquid B is sent in the same manner as in the above (1) to (3). However,
In the case of the liquid B, the letters a, f, and A in the above (1) to (3) are read as b, d, and B, respectively, and the rotation directions of the valve 3 are all read in reverse. The upper and lower parts in the above description represent the positional relationship and the movement direction in FIG. In the embodiment of FIG. 1, the following modified operation different from the above is possible. (1) When the pump 1 is set to the suction stroke in a state where the ports a and f communicate with each other, the liquid A flows from the supply source flow path 4a to the discharge port 13
Inhaled through. (2) Rotate valve 3 clockwise by 60 degrees to set port c
-F is in a state of communication. When the pump 1 is set in the discharge stroke in this state, the liquid A in the pump chamber 11 is pushed out,
The liquid is sent from the discharge port 13 to the liquid sending destination channel 5. (3) The valve 3 is rotated 60 degrees counterclockwise to the state of (1), and thereafter, the above-mentioned (1) to (3) are repeated, so that the liquid A is continuously supplied. (4) When the mobile phase is switched to the liquid B, the valve 3 is rotated clockwise 120 degrees after the plunger 12 reaches the top dead center after the state of the above (2) is completed, and the port b-d is switched. Communicate with each other. Thereafter, the liquid B is sent in the same manner as in the above (1) to (3). However, in the case of the liquid B, the characters a, f, and A in the above (1) to (3) are b, d,
B and the rotation direction of the valve 3 are all read in reverse. In the case of the above deformation operation, the suction port 1 of the pump 1
4 does not function at all, and the discharge port 13 also functions as a suction port. That is, in this case, the pump 1 functions as a single-port syringe pump. From this, it is understood that the present invention can be applied to a liquid feeding system using a single-port syringe pump as shown in FIG. FIG. 2 shows another embodiment of the present invention. In the figure, valves 3 are arranged at intervals of 60 degrees on the circumference.
A rotary valve having two ports a to f, provided with communication grooves 31 and 32 for communicating between two adjacent ports. Since the communication grooves 31 and 32 are spaced at an angle of 150 degrees (not an integral multiple of the port interval), when one of the communication grooves communicates between the two ports, the other communication groove becomes It is in a position not communicating with any port. In addition, components that are functionally the same as those in FIG. 1 are denoted by the same reference numerals, and will not be described again. Further, it is assumed that the plunger drive mechanism 20, the valve drive mechanism 30, the control unit 10, and the like, which are omitted in FIG. 2, are provided similarly to FIG. The liquid feeding system shown in FIG. 2 operates as follows. (1) The valve 3 is rotated clockwise by 30 degrees from the state shown in the figure to bring the ports ae into communication. If the pump 1 is in the suction stroke in this state, the liquid A is supplied from the supply source flow path 4a.
Inhaled through. (2) The valve 3 is rotated by 30 degrees in a counterclockwise direction so that the ports cd communicate with each other. When the pump 1 is in the discharge stroke in this state, the liquid A in the pump chamber 11 is pushed out, and is supplied from the discharge port 13 to the liquid supply destination channel 5. (3) The valve 3 is rotated 30 degrees clockwise to the state of (1), and thereafter, by repeating the above (1) to (3), the liquid A is continuously supplied. (4) When the mobile phase is switched to the liquid B, after the state of the above (2) is completed and the plunger 12 reaches the top dead center, the valve 3 is rotated counterclockwise by 30 degrees, and the ports be It is in a state where the communication is established. Thereafter, the liquid B is sent in the same manner as in the above (1) to (3). However, in the case of the liquid B, the letters a and A in the above (1) to (3) are read as b and B, respectively, and the rotation directions of the valve 3 are all read in reverse. The embodiment shown in FIG. 2 is different from the embodiment shown in FIG. 1 in that a dead end (in FIG. 1, from the connection point p to the port d or f) which prevents the replacement of the liquid in the flow path of the liquid to be sent. This is advantageous in that one of the pipes does not have a dead end, and the predetermined rotation angle of the valve 3 is small (30
) Can be switched at high speed, and is suitable for gradient liquid feeding in which switching between two liquids needs to be repeated in a short cycle. The above is only an example of some embodiments of the present invention, and the present invention is not limited to the embodiments. For example, the pump is not limited to the above-described syringe pump, but the reciprocating motion of the plunger Any pump that sucks and discharges a liquid can be applied to the present invention. The present invention is not limited to the number of ports of the valve and the numerical value of the rotation angle in the above description. As described above in detail, in the present invention, the rectifying valve attached to the pump is provided with the function of switching the two liquids of the mobile phase, and therefore has the conventional function of switching the two liquids. It is possible to provide a small-sized, low-cost, and low-energy consumption liquid-feeding system as compared with a liquid-feeding system. In addition, a high performance liquid chromatograph using this can be applied to a wider range of analysis.

[Brief description of the drawings] FIG. 1 is a diagram showing one embodiment of the present invention. FIG. 2 is a diagram showing another embodiment of the present invention. FIG. 3 is a diagram showing an example of a conventional liquid feeding system. FIG. 4 is a diagram showing another example of a conventional liquid feeding system. [Explanation of symbols] 1. Pump 3 ... Valve 4 ... supply channel 5: Liquid sending destination channel 10 ... Control unit 20 ... Plunger drive mechanism 30 ... Valve drive mechanism 31… Communication groove

Claims (1)

Claims: 1. A pump for sucking and discharging a liquid by reciprocating movement of a plunger, and a flow path switching valve for switchingly connecting a port of the pump to a liquid supply flow path and a liquid destination flow path. Valve driving for switching the flow path switching valve so that the port of the pump is connected to the supply source flow path during the suction operation of the pump and the port of the pump is connected to the liquid supply destination flow path during the discharge operation. A liquid supply system comprising: a first liquid supply source flow path as the supply source flow path and a first liquid supply source flow path as the flow path switching valve; And a second state in which the port of the pump is connected to the supply passage of the second liquid, and a port of the pump as an intermediate state between the first and second states. Is in the third state connected to the liquid transfer destination flow path A high-performance liquid chromatograph having a liquid sending system, characterized by comprising a flow path switching valve for switching between a liquid supply system and a liquid supply system.