LIQUID CHROMATOGRAPH

Abstract

A liquid chromatograph includes: a concentration column for capturing a target component; an analysis column for separating the target component from other components; first passage-switching units for switching between the state of forming a passage through which a sample-introduction mobile phase containing the liquid sample is fed to the concentration column, and the state of forming a passage through which an eluant for eluting the target component captured in the concentration column is fed to the concentration column; a storage unit for storing the eluant; and a second passage-switching unit for switching between the state of forming a passage through which an analysis mobile phase is fed to the analysis column and a passage through which the eluant from the concentration column is fed to the storage unit, and the state of forming a passage through which analysis mobile phase is fed to the analysis column via the storage unit.

Claims

1. A liquid chromatograph comprising: a) a concentration column for capturing a target component in a liquid sample; b) an analysis column for separating the target component from other components; c) a first passage-switching unit configured to switch between a state of forming a passage through which a sample-introduction mobile phase containing the liquid sample is fed to the concentration column, and a state of forming a passage through which an eluant for eluting the target component captured in the concentration column is fed to the concentration column; d) a first storage unit configured to store the eluant containing the target component; and e) a second passage-switching unit configured to switch between a state of forming a passage through which an analysis mobile phase is fed to the analysis column and a passage through which the eluant from the concentration column is fed to the first storage unit, and a state of forming a passage through which the analysis mobile phase is fed to the analysis column via the first storage unit.

2. The liquid chromatograph according to claim 1, further comprising: f) a second storage unit for storing the eluant; and g) a third passage-switching unit configured to switch between a state of forming a passage through which the eluant is fed to the second storage unit, and a state of forming a passage through which the sample-introduction mobile phase is fed to the second storage unit to wash out the eluant stored in the second storage unit to the concentration column.

3. The liquid chromatograph according to claim 2, wherein the first storage unit has a capacity greater than a capacity of the second storage unit.

4. The liquid chromatograph according to claim 1, wherein the analysis mobile phase containing the liquid sample is introducible into the analysis column without passing through the concentration column.

5. The liquid chromatograph according to claim 2, wherein the analysis mobile phase containing the liquid sample is introducible into the analysis column without passing through the concentration column.

6. The liquid chromatograph according to claim 3, wherein the analysis mobile phase containing the liquid sample is introducible into the analysis column without passing through the concentration column.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0028] FIG. 1 is a diagram showing a passage configuration in a conventional liquid chromatograph.

[0029] FIG. 2 is a diagram showing a passage configuration in a liquid chromatograph according to an embodiment of the present invention.

[0030] FIG. 3 is a diagram illustrating passages used in an eluant storing step in the liquid chromatograph according to the embodiment.

[0031] FIG. 4 is a diagram illustrating passages used in a sample injection step in the liquid chromatograph according to the embodiment.

[0032] FIG. 5 is a diagram illustrating passages used in a target-component elution step in the liquid chromatograph according to the embodiment.

[0033] FIG. 6 is a diagram illustrating passages used in an analysis step in the liquid chromatograph according to the embodiment.

DESCRIPTION OF EMBODIMENTS

[0034] An embodiment of a liquid chromatograph according to the present invention is described hereinafter, with reference to the drawings. The liquid chromatograph according to the present embodiment is used to perform pretreatment, such as the concentration and cleanup, of target components contained in a liquid sample, and then to separate the target components from other components, so as to analyze the target components.

[0035] FIG. 2 is a diagram showing a passage configuration in the liquid chromatograph according to the present embodiment. The passages in the liquid chromatograph according to the present embodiment includes three passage switching valves, which are a ten-way valve 1, a first six-way valve 11, and a second six-way valve 13. The ten-way valve 1 serves as a first passage-switching unit of the present invention in conjunction with pumps 4 and 6 which are described later. The first six-way valve 11 and the second six-way valve 13 respectively serve as a third passage-switching unit and a second passage-switching unit of the present invention. The first six-way valve 11 used for the introduction and pretreatment of a sample is a low pressure valve, whereas the second six-way valve 13 used for feeding an analysis mobile phase is a high-pressure valve.

[0036] The ten-way valve 1 includes passages each of which permanently connects port A to port F, and port B to port H. In addition, the ten-way valve 1 includes ports C, E, J, D, G, and K. Port C is connected to an analysis column unit 40, port E to port J via a sample injection unit 2, port D to an analysis mobile-phase supply passage 27, port G to a pretreatment aqueous-solvent supply passage 22, and port K to a pretreatment solvent supply passage 24, respectively.

[0037] The first 6-port valve 11 includes ports a, b, f, and c. Port a connects to port m of the second 6-port valve 13, port b to port f via a concentration column unit 30, and port c to the pretreatment solvent supply passage 24. In addition, the first 6-port valve 11 further includes ports d and e which are connected through a passage provided with a second storage unit 12 having 50 μl capacity.

[0038] The second six-way valve 13 includes ports g, j, h, i, and k. Ports g and j are connected through a passage on which a first storage unit 14 having 100 μl capacity is disposed. Port h is connected to an analysis aqueous-solvent supply passage 25, port i to the analysis mobile-phase supply passage 27, and port k to a disposal passage 28, respectively.

[0039] The pretreatment aqueous-solvent supply passage 22 is provided with a container 3 storing a pretreatment aqueous solvent and a pump 4 for feeding the aqueous solvent stored in the container 3 to port G of the ten-way valve 1.

[0040] A pretreatment organic-solvent supply passage 23 is provided with a container 5 storing a pretreatment organic-solvent and a pump 6 for feeding the organic solvent stored in the container 5 to a pretreatment mixer 9 disposed on the pretreatment solvent supply passage 24.

[0041] The analysis aqueous-solvent supply passage 25 is provided with a container 15 storing an analysis aqueous solvent and a pump 16 for feeding the aqueous solvent stored in the container 15 to port h of the second six-way valve 13.

[0042] An analysis organic-solvent supply passage 26 is provided with a container 7 storing an analysis organic solvent and a pump 8 for feeding the organic solvent stored in the container 7 to an analysis mixer 10 disposed on the analysis mobile-phase supply passage 27.

[0043] The concentration column unit 30 includes six concentration columns 32 arranged in parallel, and two passage switching units 31 and 33 for switching passages which are individually connected to the six concentration columns 32. The six concentration columns 32 individually contain capture agents carried on polymers, each column having a different diameter, length, and type of capture agent.

[0044] Similar to the above, the analysis column unit 40 includes six analysis columns 42 arranged in parallel, and two passage switching units 41 and 43 for switching passages individually connected to the six analysis columns 42. The six analysis columns 42 individually contain solid phases carried on silicates, each column having a different diameter, length and type of the solid phase.

[0045] The analysis column unit 40 is adjacent to, in its discharge side, a detector 50 which sequentially detects components (and the analysis mobile phase) separated in the analysis columns 42.

[0046] Operations for the pretreatment and the analysis on samples using the liquid chromatograph according to the present embodiment are described hereinafter, with reference to FIGS. 3 to 6. In these drawings that refer to the respective steps, the passages through which solvents flow are shown by solid lines. In the present embodiment, a pretreatment aqueous solvent is used for the sample-introduction mobile phase, a pretreatment organic solvent is used for the eluant, and a mixture of the pretreatment aqueous solvent with the pretreatment organic solvent is used for the cleanup liquid. In addition, a mixture of the analysis aqueous solvent with the analysis organic solvent is used for the analysis mobile phase.

[0047] [Eluant Storing Step]

[0048] In the eluant storing step, an eluant is stored in the second storage unit 12 through passages shown by solid lines in FIG. 3.

[0049] The eluant storing step specifically proceeds as follows. Pump 6 is operated to feed the pretreatment organic solvent to port c of the first six-way valve 11 through the pretreatment organic-solvent supply passage 23 and the pretreatment solvent supply passage 24. Thus, the pretreatment organic solvent (eluant) in an amount of 50 μl is stored in the second storage unit 12 disposed between port d and port e.

[0050] In parallel, pump 16 is operated to feed the analysis aqueous solvent to the analysis mixer 10 through the analysis aqueous-solvent supply passage 25 and the second six-way valve 13. In the second six-way valve 13, the analysis aqueous solvent flows through port h, port g, the first storage unit 14, port j, and port i, in that order. Pump 8 is simultaneously operated to feed the analysis organic solvent to the analysis mixer 10. The analysis mixer 10 mixes the analysis aqueous solvent with the analysis organic solvent to prepare an analysis mobile phase. The obtained analysis mobile phase is fed to the analysis columns 42 in the analysis column unit 40 through the analysis mobile-phase supply passage 27 and ports D and C of the ten-way valve 1. It should be noted that the analysis mobile phase is fed to the analysis columns 42 through this route, up to a cleanup step, which will be described later.

[0051] [Sample Injection Step]

[0052] In the eluant storing step, target components in the liquid sample are captured in the concentration columns 32 using passages shown by solid lines in FIG. 4.

[0053] First, passages in the first six-way valve 11 are switched. Then, pump 4 is operated to feed the pretreatment aqueous solvent (sample-introduction mobile phase) to port G in the ten-way valve 1 through the pretreatment aqueous-solvent supply passage 22. In parallel, a liquid sample is injected from the sample injection unit 2 to the sample-introduction mobile phase. Then, the liquid sample being carried by the flow of the sample-introduction mobile phase flows through the pretreatment solvent supply passage 24, and ports c and b of the first six-way valve 11, to be introduced in the concentration columns 32. The target components contained in the liquid sample are thus captured in the concentration columns 32.

[0054] [Cleanup Step]

[0055] In the cleanup step, the target components captured in the concentration columns 32 are cleaned using the pretreatment organic-solvent supply passage 23 in addition to the passages shown by the solid lines in FIG. 4.

[0056] In this step, the sample injection unit 2 is stopped, and pump 6 is operated to feed the pretreatment organic solvent to the pretreatment mixer 9. In the pretreatment mixer 9, the pretreatment aqueous solvent and the pretreatment organic solvent are mixed. The obtained mixture liquid (cleanup solvent) is fed to the concentration columns 32 through the same form of passages as the aforementioned ones. The cleanup solvent is used to remove unnecessary components other than the target components captured inside the concentration columns 32. A cleanup liquid containing the unnecessary components is discharged to the disposal passage through the first six-way valve 11 and the second six-way valve 13.

[0057] [Target Component Elution Step]

[0058] In the target component elution step, the target components captured in the concentration columns 32 are eluted using the passages shown by the solid lines in FIG. 5, and are stored in the first storage unit 14.

[0059] In this step, the passages in both of the first and six-way valves 11 and 13 are switched. After the switching, the passages in the first six-way valve 11 allows the mixture liquid of the pretreatment aqueous solvent with the pretreatment organic solvent to be fed to the second storage unit 12. The 50 μl of the pretreatment organic solvent (eluant) stored in the second storage unit 12 is washed out by the mixture liquid so as to be introduced into the concentration columns 32. The target components captured in the concentration columns 32 are eluted in the eluant, and fed through ports b and a in the first six-way valve 11, and then through ports m and g in the second six-way valve 13, to the first storage unit 14. The analysis aqueous solvent introduced in the first storage unit 14 in the previous step is thus washed out by the eluant containing the target components so as to be discharged to the disposal passage 28.

[0060] In the target component elution step, the analysis aqueous solvent fed through the analysis aqueous-solvent supply passage 25 is fed to the analysis mixer 10 through port h and port i of the second six-way valve 13. In the analysis mixer 10, the analysis aqueous solvent is mixed with the analysis organic solvent, and fed to the analysis columns 42. Thus, the analysis mobile phase is fed to the analysis columns 42 through passages different from those used in the previous steps up to the cleanup step.

[0061] [Analysis Step]

[0062] In the analysis step, the eluant containing the target components which is stored in the first storage unit 14, is introduced into the analysis columns 42 using the passages shown by the solid lines in FIG. 6.

[0063] In this step, the passages in the second six-way valve 13 are switched so that the analysis aqueous solvent supplied through the analysis aqueous-solvent supply passage 25 is fed to the first storage unit 14. The eluant containing the target components which is stored in the first storage unit 14 is thus washed out by this aqueous solvent so as to be fed to the analysis mixer 10. Meanwhile, in the analysis mixer 10, the analysis aqueous solvent and the analysis organic solvent are mixed. Accordingly, the target components are carried through port D and port C of the ten-way valve 1 by the flow of the analysis mobile phase, to be introduced into the analysis columns 42. In the analysis columns 42, the target components undergo component separation, and are then detected by the detector 50.

[0064] During the separation and detection of the target components, the passages in the first six-way valve 11 are switched, and the pump 4 is operated to feed the pretreatment aqueous solvent (sample-introduction mobile phase) to the concentration columns 32, to thereby replace the solvent in the passages with the pretreatment aqueous solvent. The next analysis is thus prepared.

[0065] As described thus far, the liquid chromatograph according to the present embodiment includes passages for feeding an eluant (pretreatment organic solvent) to the concentration columns 32, and passages for feeding an analysis mobile phase to the analysis columns 42, separately. This prevents the analysis mobile phase from being fed to the concentration columns 32 under high pressure, and a large amount of eluant from being fed to the analysis columns 42. In addition, the eluant containing the target components eluted from the concentration columns 32 is temporarily stored in the first string unit 14. Accordingly, it is possible to use one column suited for the pretreatment of the target components, such as the concentration and cleanup, and another separate column suited for the separation and analysis of the target components. In addition, optimal eluant can be used for each of those purposes.

[0066] In the liquid chromatograph according to the above embodiment, target components can also be introduced into the analysis columns 42 without pretreatment (i.e., without capturing target components inside the concentration columns 32). Details are as follows. Passages are switched in the ten-way valve 1, and a liquid sample is injected from the sample injection unit 2. With this, the liquid sample can be carried into the analysis columns 42 by the flow of the analysis mobile phase fed from the analysis mixer 10. Thus, the liquid chromatograph according to the present embodiment can provide passages suitable for both analyses with and without pretreatment of target components, such as the concentration and cleanup.

[0067] The aforementioned embodiment is a mere example of the present invention, and can be appropriately modified in accordance with the purposes of the present invention.

[0068] In the aforementioned embodiment, a pretreatment aqueous solvent is used for the sample-introduction mobile phase, a pretreatment organic solvent is used for the eluant, a mixture of those two liquids is used for the cleanup liquid, and a mixture of an analysis aqueous solvent with an analysis organic solvent is used for the analysis mobile phase. These can be appropriately modified according to target components.

[0069] Furthermore, in the aforementioned embodiment, the pretreatment mixer 9 is disposed between port K of the ten-way valve 1 and port c of the first six-way valve 11, whereas the analysis mixer 10 is disposed between port i of the second six-way valve 13 and the ten-way valve D. These mixers can be, however, disposed at any other location where the desired mixture liquid can be prepared. In view of accurate control on the mixture ratio of the solvents, the mixers may be disposed at positions as close as possible to the respective target columns, as in the present embodiment.

[0070] Furthermore, though the capacity of the first storage unit 14 is set to 100 μl, and that of the second storage unit 12 is set to 50 μl in the present embodiment, these capacities may be modified according to the volume of target components, or other factors. In order to ensure that an eluant in which the target components are eluted is supplied to the analysis, the capacity of the first storage unit 14 may preferably be greater than that of the second storage unit 12. For example, the former capacity may be twice as large as the latter, as in the present embodiment.

REFERENCE SIGNS LIST

[0071] 1 . . . Ten-Way Valve [0072] 2 . . . Sample Injection Unit [0073] 9 . . . Pretreatment Mixer [0074] 10 . . . Analysis Mixer [0075] 11, 13 . . . Six-Way Valve [0076] 12 . . . Second Storage Unit [0077] 14 . . . First Storage Unit [0078] 22 . . . Pretreatment Aqueous-Solvent Supply Passage [0079] 23 . . . Pretreatment Organic-Solvent Supply Passage [0080] 24 . . . Pretreatment Solvent Supply Passage [0081] 25 . . . Analysis Aqueous-Solvent Supply Passage [0082] 26 . . . Analysis Organic-Solvent Supply Passage [0083] 27 . . . Analysis Mobile-Phase Supply Passage [0084] 28 . . . Disposal Passage [0085] 30 . . . Concentration Column Unit [0086] 31 . . . Passage Switching Valve [0087] 32 . . . Concentration Column [0088] 40 . . . Analysis Column Unit [0089] 41 . . . Passage Switching Valve [0090] 42 . . . Analysis Column [0091] 50 . . . Detector