JP2004093251A - Liquid chromatograph - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To change the gradient of eluant more rectilinearly by mixing two solvents at an arbitrary ratio. <P>SOLUTION: A liquid chromatograph 1, where the eluant where the two solvents are mixed at the arbitrary ratio, is successively sent to a column 10 and liquid chromatography is conducted comprises a first solenoid valve 4, where respective channels 14, 15 for sending liquid from the two solvents are connected, with the two solvents being alternately switched for circulating, and to prepare a first eluant; a second solenoid valve 7, where a channel 5 for sending liquid from one solvent of the two solvents is connected with a channel 6 for sending liquid from the first solenoid valve 4, the one solvent and the first eluant are alternately swithed for circulating, and to prepare a second eluant; and a pump 8 for sucking the solvent and eluant and sending them to the column 10, with a channel 16 for sending liquid from the second valve 7 linked. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid chromatograph capable of changing the gradient of an eluent obtained by mixing two solvents at an arbitrary ratio in a substantially linear manner.
[0002]
[Prior art]
In the conventional liquid chromatograph 40, the container 41 storing the solvent C and the container 42 storing the solvent D as shown in FIG. 4 are provided at positions where the solvent C and the solvent D are connected. The three-way solenoid valve 43, the pump 45, the injector 46, the column 47 and the like are provided. In addition, the liquid sending flow paths arranged in this order are formed.
[0003]
The control device 48 is connected to the three-way solenoid valve 43. The three-way solenoid valve 43 is switched by the signal from the control device 48, and the solvent C and the solvent D sucked by the pump 45 alternately flow through the liquid sending flow path connected to the pump 45 and are mixed. The eluent is made.
[0004]
Then, the eluent passes through the injector 46 having the sample by the pump 45, and the sample and the eluent are supplied to the column 47 filled with the stationary phase. Since each component in the sample introduced into the column 47 passes through the column 47 at a different time, each component is separated at the time when the component is discharged from the column 47.
[0005]
In such a liquid chromatograph 40, in order that the components of the sample discharged from the column 47 do not overlap and the separation is performed in a short time, a gradient in which the mixing ratio of the eluent is gradually changed is performed.
[0006]
[Problems to be solved by the invention]
However, in the gradient of the eluent obtained by alternately switching between the solvent C and the solvent D having a concentration of 100% by one three-way solenoid valve 43 of the liquid chromatograph 40, for example, the solvent D is contained in the solvent C. In the gradient of the eluent up to about 5%, as shown in FIG. 5, each time the solenoid valve 43 is switched, the mixing ratio of the time Ga in which the solvent D rises to 5% fluctuates irregularly. That is, at the same time as the suction by the pump 45, the solenoid valve 43 is switched to the side through which the solvent D flows so that the high concentration of the solvent D flows, but since the concentration of the solvent D is high, the solenoid valve 43 flows through the solvent D. It is necessary to switch so as to make the time to make it extremely short, and if there is any inconvenience between the timing of suction by the pump 45 and the timing of switching of the side through which the solvent D flows by the electromagnetic valve 43, as shown in FIG. The ratio is disturbed up and down, and the separation of each component of the sample discharged from the column 47 in the time width Ga varies, which causes a problem in reproducibility of each component.
[0007]
Further, the solvent C is mixed with the solvent D, for example, a solvent D containing the solvent C at a ratio of 50% is prepared in advance, and the solvent D and the solvent C are alternately switched by a three-way solenoid valve. When the gradient of the eluent is performed, the irregularity of the change in the mixing ratio is reduced more than the gradient of the eluent obtained by mixing the solvent D and the solvent C at a concentration of 100%, and the eluent is substantially linearly mixed. The mixing ratio changes. However, since the solvent D contains 50% of the solvent C, it cannot be used when used for other purposes. In addition, since the solvent D is mixed with the solvent C in a separate operation, it takes time and has a problem in workability.
[0008]
Therefore, an object of the present invention is to provide a liquid chromatograph that can reduce irregularities in a change in a mixing ratio in a gradient of an eluent without previously mixing two solvents.
[0009]
[Means for Solving the Problems]
The liquid chromatograph according to claim 1 of the present invention, wherein an eluent obtained by mixing two solvents at an arbitrary ratio is sequentially sent to a column to perform liquid chromatography, wherein the two solvents are mixed. A first solenoid valve for generating a first eluent by alternately switching the two solvents to flow therethrough, and a liquid sending channel from one of the two solvents And a liquid supply flow path from the first electromagnetic valve are connected to each other, the second electromagnetic valve for alternately switching the first solvent and the first eluent to circulate to produce a second eluent, and the second electromagnetic valve. And a pump for sucking the solvent and the eluent and sending them to the column.
[0010]
According to such a configuration, by switching the first solenoid valve, a first eluent in which the solvent A and the solvent B are mixed is prepared in advance, and then by switching the second solenoid valve, the second eluent is formed, whereby the mixing ratio is increased. The irregularity of the change is reduced, and a gradient can be formed at a higher mixing ratio. That is, by making the first eluent in which the solvent A and the solvent B are mixed, it is possible to switch so as to make the time for flowing the first eluent of the second solenoid valve longer, and to reduce the ratio as in the related art. It is not necessary to switch the solenoid valve at high speed so as to shorten the time for flowing the mixed solvent. In addition, since the time for flowing the first eluent through the second solenoid valve can be lengthened, the occurrence of a wraparound at the timing of pump suction for sucking the second eluent is reduced. Therefore, the mixing ratio of the second eluent changes more linearly, the components of the sample discharged from the column do not overlap, and the degree of separation of the components of the sample by a gradient that performs separation in a short time is improved. . In addition, since the first eluent in which the solvent A and the solvent B are mixed can be made in the liquid chromatograph, the workability can be improved because the solvent (the first eluent) previously mixed is not made in a separate operation.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS.
[0012]
FIG. 1 is a schematic diagram showing a liquid chromatograph according to the present invention. As shown in FIG. 1, the liquid chromatograph 1 has a container 2 storing a solvent A, a container 3 storing a solvent B, and respective liquid sending channels 14 and 15 connected from the solvent A and the solvent B. A first electromagnetic valve 4, a second electromagnetic valve 7 to which a liquid supply flow path 5 from the solvent A and a liquid supply flow path 6 from the first electromagnetic valve 4 are connected, a pump 8, an injector 9, It is composed of a column 10, a detector 11, and a fraction collector 12, and a liquid sending flow path arranged in this order is formed. A liquid chromatograph controller 13 is connected to the first solenoid valve 4 and the second solenoid valve 7. Note that the solvent A is 100% -concentration chloroform, and the solvent B is 100% -concentration methanol. However, the solvent A can be appropriately changed depending on a sample to be subjected to liquid chromatography.
[0013]
The pump 8 sucks the solvent A and the solvent B via the first solenoid valve 4 and the second solenoid valve 7. Accordingly, the later-described first eluent obtained by the first solenoid valve 4 and the later-described second eluate obtained by the second solenoid valve 7 are also sucked. Further, the pump 8 can suck each solvent and each eluent, and send them to the injector 9 and the column 10.
[0014]
The first solenoid valve 4 selects a solvent to be sucked from the solvent A or the solvent B according to a control signal from the liquid chromatograph controller 13. The first electromagnetic valve 4 selected in this way switches the liquid supply flow path 14 from the solvent A and the liquid supply flow path 15 from the solvent B, so that either the solvent A or the solvent B is provided on the second electromagnetic valve 7 side. One of them is alternately circulated in the liquid sending flow path 6.
[0015]
The solvent A and the solvent B that have passed through the first solenoid valve 4 in this manner are mixed with the solvent A and the solvent B in the liquid feed line 6 between the first solenoid valve 4 and the second solenoid valve 7 to perform the first elution. A liquid is made. Therefore, it is not necessary to prepare a solvent (first eluent) mixed in advance in another operation, that is, a mixture in which the solvent A and the solvent B are mixed at a predetermined concentration, so that the operation of another operation is omitted and the workability is improved. The mixing ratio of the first eluent is determined by the flow time of the solvent A or the solvent B selected by the first solenoid valve 4.
[0016]
The second solenoid valve 7 selects the solvent to be sucked from the solvent A or the first eluent according to a control signal from the liquid chromatograph control device 13 as in the first solenoid valve 4. The second electromagnetic valve 7 selected in this way switches the liquid sending flow path 5 from the solvent A and the liquid sending flow path 6 from the first electromagnetic valve 4, and sends the solvent A or the first eluent to the pump 8 side. Either one is alternately circulated in the liquid feed channel 16.
[0017]
The solvent A and the first eluent that have passed through the second electromagnetic valve 7 in this manner are mixed with the solvent A and the first eluent in the liquid sending flow path 16 between the second electromagnetic valve 7 and the injector 9 to produce the second eluent. An eluent is made. The mixing ratio of the second eluent is determined by the flow time of the solvent A or the first eluent selected by the second solenoid valve 7.
[0018]
The injector 9 has a sample for separating each component by liquid chromatography, and the sample is sent out when the second eluent passes. Note that the number of injectors 9 is not limited to one, and a plurality of injectors can be selectively provided and arranged side by side, and it is also possible to continuously work on a plurality of samples.
[0019]
The column 10 is packed with a stationary phase, and liquid chromatography is performed by passing the second eluent. Silica gel is used as the stationary phase. The number of columns 10 is not limited to one, and a plurality of columns can be selected and arranged in parallel, and a plurality of types of liquid chromatography can be performed.
[0020]
The detector 11 detects the result of the liquid chromatography performed in the column 10. The fraction collector 12 has a plurality of test tubes, and according to the analysis result of the detector 11, the components are separated into test tubes for each component contained in the sample.
[0021]
Further, the liquid chromatograph control device 13 is constituted by an information processing device such as a general-purpose personal computer. Further, the first solenoid valve 4 and the second solenoid valve 7 are provided with an electromagnetic valve operating unit for transmitting an open / close signal based on an instruction from a mixing ratio control unit of a CPU mounted inside the liquid chromatograph control device 13. It is connected. Therefore, the opening / closing control of the first solenoid valve 4 and the second solenoid valve 7 is performed by the opening / closing signal from the mixing ratio control section of the liquid chromatograph controller 13.
[0022]
FIG. 2 is a graph showing an example of a change over time of the mixing ratio of the eluent by the liquid chromatograph according to the present embodiment. As shown in FIG. 2, the horizontal axis represents the elapsed time T, and the vertical axis represents the ratio of the solvent B contained in the second eluent. G is a time width indicating a change state of a gradient by liquid chromatography.
[0023]
In the time period G shown in FIG. 2, in the gradient of the liquid chromatograph 1, the first eluent in which the solvent A and the solvent B are mixed in advance by switching the first solenoid valve 4 (for example, the ratio of the solvent A to the solvent B is changed). 50%), the solvent A and the first eluent are alternately circulated by switching the second solenoid valve to produce a second eluent in which the first eluent is gradually increased. The mixing ratio changes substantially linearly in the time width G shown in FIG.
[0024]
The reason why the mixing ratio changes substantially linearly is that the solvent A and the first eluent are mixed by preparing the first eluent containing the solvent A and the solvent B in advance. This is because the irregularity of the change in the mixing ratio can be reduced in the second eluent. In other words, when the solvent A and the solvent B both having a concentration of 100% are mixed to form an eluent having a low ratio in one of them, the opening / closing switching cycle of the solenoid valve cannot be set to a certain time or less. Changes with the switching of the solenoid valve, and the mixture ratio changes irregularly.
[0025]
The solvent A and the solvent B are appropriately selected depending on the sample to be subjected to liquid chromatography. Among the solvents, a solvent having a higher concentration of the second eluent is referred to as a solvent B, and a solvent having a lower concentration is referred to as a solvent. A.
[0026]
In addition, by exchanging the solvent A and the solvent B in the liquid chromatograph 1, it is possible to perform the gradient of the second eluent in which the ratio of the solvent B gradually decreases in the time width Gr as shown in FIG. That is, by switching the first solenoid valve 4, a first eluent is prepared by mixing the solvent A and the solvent B, and by switching the second solenoid valve 7, the solvent B and the first eluent are alternately circulated. By gradually increasing the second eluent, the mixing ratio in the time width Gr shown in FIG. 3 changes substantially linearly.
[0027]
The gradient in the liquid chromatograph 1 as described above is obtained by preparing the first eluent in which the solvent A and the solvent B are mixed in advance by switching the first electromagnetic valve 4 and then switching the second electromagnetic valve 7 to switch the second eluent. By making the eluent, the irregularity of the change of the mixing ratio of the second eluent can be reduced, and only one solenoid valve is used in the time width G as shown in FIG. As compared with the case, the irregularity of the change in the mixing ratio is reduced, and a gradient can be formed at a higher mixing ratio. That is, by making the first eluent in which the solvent A and the solvent B are mixed, it is possible to switch so as to make the time for flowing the first eluent of the second solenoid valve 7 longer, and to reduce the ratio as in the conventional case. It is not necessary to switch the solenoid valve at high speed so as to shorten the time for flowing the mixed solvent. In addition, since the time for flowing the first eluent through the second solenoid valve 7 can be lengthened, the amount of wrapping occurring at the time of pump suction for sucking the second eluent is reduced. Accordingly, as shown in FIG. 2, the mixing ratio of the second eluent changes more linearly, and each component of the sample discharged from the column 8 does not overlap, and each component of the sample is separated by a gradient that performs separation in a short time. Is improved.
[0028]
In addition, even when the solvent B in the second eluent has a gradient with a low ratio of up to about 5%, the ratio of the solvent B in the first eluent formed by switching the first solenoid valve 4 can be reduced. The first eluent produced by switching the second solenoid valve 7 and the second eluent in which the solvent A is mixed can form a gradient at a higher mixing ratio. In other words, since the ratio of the solvent B in the first eluent is low, the time required for the first eluent to flow through the second solenoid valve 7 can be lengthened. This is because the second eluent can be prepared in the same manner as the gradient of the second eluent.
[0029]
【The invention's effect】
As described above, according to the present invention, the mixing ratio of the two solvents is arbitrarily changed by the two three-way solenoid valves to change the mixing ratio of the two solvents in the gradient of the eluent. Can be alleviated, so that the degree of separation of each component of the sample in liquid chromatography can be improved. In addition, there is no need to prepare a solvent mixed in advance in a separate operation, and there is an effect that workability is improved.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a liquid chromatograph according to the present invention.
FIG. 2 is a graph showing an example of a change over time of a mixing ratio of an eluent by a liquid chromatograph according to the present embodiment.
FIG. 3 is a graph showing another example of the change over time of the mixing ratio of the eluent with the liquid chromatograph according to the present embodiment.
FIG. 4 is a schematic diagram showing a conventional liquid chromatograph.
FIG. 5 is a graph showing an example of a change over time of a mixing ratio of an eluent according to a conventional liquid chromatograph.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Liquid chromatograph 2, 3 container 4 1st solenoid valve 5, 6, 14, 15, 16 Liquid supply flow path 7 2nd solenoid valve 8 Pump 9 Injector 10 Column 11 Detector 12 Fraction collector 13 Liquid chromatograph controller

Claims (1)

A liquid chromatograph in which an eluent obtained by mixing two solvents at an arbitrary ratio is sequentially sent to a column and liquid chromatography is performed,
A first solenoid valve that connects the respective liquid sending flow paths from the two solvents and alternately switches and distributes the two solvents to create a first eluent;
The liquid sending flow path from one of the two solvents and the liquid sending flow path from the first solenoid valve are connected, and the one solvent and the first eluent are alternately switched and allowed to flow. A second solenoid valve for producing an eluent;
A liquid chromatograph, comprising: a pump connected to a liquid sending flow path from the second solenoid valve, for sucking a solvent and an eluent, and sending it to a column.

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