liquid chromatography

Abstract

This liquid chromatograph (1) includes a controller (100), a liquid feed unit (200), a first separation column (410), a second separation column (420), a first switching valve (510), and a second switching valve (520). Each of the first switching valve (510) and the second switching valve (520) has two states. The controller (100) combines the two states of each of the first switching valve (510) and the second switching valve (520) to form first to third modes in a flow path including the first switching valve (510) and the second switching valve (520), thereby realizing a SARA analysis using the first separation column (410) and the second separation column (420) in the preparative liquid chromatograph (1).

Description

Technical Field

[0001] The present disclosure relates to a liquid chromatograph, and particularly to a liquid chromatograph including two separation columns.

Background Art

[0002] Conventionally, various studies have been made on the analysis of SARA (Saturate, Aromatics, Resin, Asphaltene) components in petroleum compositions such as crude oil. The "SARA" components mean four components: Saturate (saturated fraction), Aromatics (aromatic fraction), Resin (resin fraction), and Asphaltene (asphaltene fraction). As an example of the analysis of SARA components, an analysis method using two separation columns has been disclosed (see K.K. (Adry) Bissada, Jingqiang Tan, Ewa Szymczyk, Mike Darnell, Mei Mei, Group-type characterization of crude oil and bitumen. Part I: Enhanced separation and quantification of saturates, aromatics, resins and asphaltenes (SARA), Organic Geochemistry, May 2016, Vol. 95, pp. 21-28 (Non-Patent Document 1)).

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

[0004] When implementing the analysis method for SARA components, it is necessary to consider the specific configuration of the liquid chromatograph. [Means for solving the problem]

[0005] A liquid chromatograph according to a certain aspect of the present disclosure comprises a first column, a second column, a liquid delivery unit configured to deliver a mobile phase to at least one of the first and second columns, a first switching valve having at least two connected states, a second switching valve connected to the first switching valve and having at least two connected states, and a control unit configured to form a first, second, and third configuration in a flow path including the first and second switching valves by combining one of the two connected states of the first switching valve and one of the two connected states of the second switching valve. In the first configuration, the mobile phase from the liquid delivery unit is delivered in the following order: one end of the first column, the other end of the first column, one end of the second column, and the other end of the second column. In the second configuration, the mobile phase from the liquid delivery unit is not introduced to the first column, and the mobile phase is delivered from the other end of the second column to one end of the second column. In the third configuration, the mobile phase from the liquid delivery unit is delivered from the other end of the first column to one end of the first column, and the mobile phase from the liquid delivery unit is not introduced to the second column. [Effects of the Invention]

[0006] This disclosure provides a liquid chromatograph configuration that embodies a method for analyzing SARA components. [Brief explanation of the drawing]

[0007] [Figure 1] This is a diagram showing the configuration of a liquid chromatograph. [Figure 2] This is a diagram showing the first configuration of the flow path. [Figure 3] This is a diagram showing the second form of the flow path. [Figure 4] This figure shows the third form of the flow path. [Figure 5] This figure shows the fourth configuration of the flow path. [Figure 6] This is a flowchart of the process for analyzing the SARA component. [Figure 7] This is a flowchart of the process for analyzing the SARA component. [Modes for carrying out the invention]

[0008] Hereinafter, a liquid chromatograph according to an embodiment of this disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their descriptions will not be repeated.

[0009] [Configuration of a liquid chromatograph] Figure 1 shows the configuration of liquid chromatograph 1. In one implementation example, liquid chromatograph 1 is used for the analysis of SARA components.

[0010] As shown in Figure 1, the liquid chromatograph 1 includes a controller 100, a liquid delivery unit 200, a sampler 300, a first separation column 410, a second separation column 420, a first switching valve 510, a second switching valve 520, and a detector 600.

[0011] The controller 100 controls the operation of the liquid chromatograph 1. The controller 100 includes a processor 101, a storage device 102, and an interface 103. In one implementation, the controller 100 controls the operation of the liquid chromatograph 1 by having the processor 101 execute a program stored in the storage device 102. The processor 101 may also execute a program stored in a storage medium removable from the controller 100. The interface 103 is implemented by a communication interface (e.g., a network card). The processor 101 communicates with other elements within the liquid chromatograph 1 (such as the sampler 300) and with devices outside the liquid chromatograph 1 via the interface 103.

[0012] The liquid delivery unit 200 delivers the solution to be used as the mobile phase into the mobile phase flow path, which includes a first switching valve 510 and a second switching valve 520. This supplies the mobile phase to the first separation column 410 and / or the second separation column 420.

[0013] More specifically, the fluid delivery unit 200 includes five fluid delivery pumps 201-205 and a switching unit 210. Each of the fluid delivery pumps 201-204 is connected to a tank containing each of the four types of mobile phases used in SARA analysis, and delivers each mobile phase to the switching unit 210.

[0014] The four mobile phases consist of a first mobile phase for saturated extraction (e.g., hexane), a second mobile phase for resin extraction (e.g., a mixture of 94% hexane and 6% chloroform), a third mobile phase for asphaltene extraction (a mixture of 15% methanol, 15% acetone, and 70% chloroform), and a fourth mobile phase for aromatic extraction (e.g., chloroform).

[0015] The liquid delivery pump 205 is connected to a tank that stores the cleaning liquid for the first separation column 410 and the second separation column 420, and sends the cleaning liquid toward the switching unit 210. Note that the cleaning liquid may be the above-described first mobile phase, second mobile phase, third mobile phase, and / or fourth mobile phase. In this case, in the liquid chromatograph 1, the liquid delivery pump 205 may be omitted.

[0016] The switching unit 210 switches the pump that sends the mobile phase toward the first switching valve 510 from among the liquid delivery pumps 201 to 205. In one implementation example, the switching unit 210 includes five inlets connected to each of the liquid delivery pumps 201 to 205, five solenoid valves provided at each of the five inlets, and one outlet connected to the sampler 300. Then, the switching unit 210 connects a part of the five inlets to the one outlet by switching the opening and closing of each of the five solenoid valves, thereby realizing the switching of the above pumps.

[0017] The sampler 300 supplies an analysis sample toward the above flow path. In the example of FIG. 1, the sampler 300 is directly connected to the port 516 of the first switching valve 510. That is, the flow path including the first switching valve 510 and the second switching valve 520 is configured such that the mobile phase sent from the liquid delivery unit is sent to the first switching valve 510 via the sampler 300 (sample introduction unit). Thereby, when the liquid chromatograph 1 performs the analysis of SARA components, in the portion from the sampler 300 to the first switching valve 510 of the above flow path, no new elements (such as switching valves) for sending the sample and the mobile phase to the first switching valve 510 are required. Therefore, in the liquid chromatograph 1 that performs the analysis of SARA components, an increase in manufacturing cost is avoided.

[0018] Each of the first separation column 410 and the second separation column 420 separates the target component contained in the sample by supplying the sample together with the mobile phase. Each of the first separation column 410 and the second separation column 420 is housed in a column oven (not shown) and maintained at the temperature set in the analysis method by the column oven.

[0019] Both ends of the first separation column 410 are shown as end 411 and end 412. In the first separation column 410, the flow from end 411 to end 412 is referred to as the "forward" flow. Also, the flow from end 412 to end 411 is referred to as the "reverse" flow (backflush).

[0020] Both ends of the second separation column 420 are shown as end 421 and end 422. In the second separation column 420, the flow from end 421 to end 422 is referred to as the "forward" flow. Also, the flow from end 422 to end 421 is referred to as the "reverse" flow (backflush).

[0021] When the liquid chromatograph 1 is used for the analysis of SARA components, an alkyl nitrile may be employed as the packing material of the first separation column 410. That is, a cyanocolumn may be employed as the first separation column 410. Also, silica may be employed as the packing material of the second separation column 420. That is, a silica column may be employed as the second separation column 420.

[0022] The detector 600 analyzes the sample supplied from the first separation column 410 and / or the second separation column 420. The detector 600 is realized, for example, by an ultraviolet-visible spectrophotometer, a diode array detector, and / or a differential refractive index detector.

[0023] Each of the first switching valve 510 and the second switching valve 520 is implemented, for example, by a 6-port, 2-position switching valve. The first switching valve 510 includes 6 ports 511 to 516. The second switching valve 520 includes 6 ports 521 to 526.

[0024] The first switching valve 510 is connected to the second separation column 420. More specifically, port 513 is connected to end 421 of the second separation column 420. Port 511 is connected to end 422 of the second separation column 420.

[0025] The second switching valve 520 is connected to the first separation column 410. More specifically, port 525 is connected to end 411 of the first separation column 410. Port 521 is connected to end 412 of the first separation column 410.

[0026] [Four forms of flow channels] In the liquid chromatograph 1, four configurations (first to fourth configurations) are formed in the flow path including the first and second switching valves 510 and 520 by combining the two positions of the first and second switching valves 510 and 520, respectively. Figure 2 shows the first configuration of the flow path. Figure 3 shows the second configuration of the flow path. Figure 4 shows the third configuration of the flow path. Figure 5 shows the fourth configuration of the flow path. The two positions of the first and second switching valves 510 and 520, and the four configurations of the flow path will be described below with reference to Figures 2 to 5.

[0027] <Two positions of the first switching valve 510> The two positions of the first switching valve 510 are referred to as position 0 and position 1. Figures 2 to 5 show the positions of the first switching valve 510.

[0028] Position 0 of the first switching valve 510 is shown, for example, in Figure 2. In this position, ports 511 and 512 are connected, ports 513 and 514 are connected, and ports 515 and 516 are connected.

[0029] Position 1 of the first switching valve 510 is shown, for example, in Figure 4. In this position, ports 511 and 516 are connected, ports 513 and 512 are connected, and ports 515 and 514 are connected.

[0030] <Two positions of the second switching valve 520> The two positions of the second switching valve 520 are referred to as position 0 and position 1. Figures 2 to 5 show the positions of the second switching valve 520.

[0031] Position 0 of the second switching valve 520 is shown, for example, in Figure 2. In this position, ports 521 and 522 are connected, ports 523 and 524 are connected, and ports 525 and 526 are connected.

[0032] Position 1 of the second switching valve 520 is shown, for example, in Figure 3. In this position, ports 521 and 526 are connected, ports 523 and 522 are connected, and ports 525 and 524 are connected.

[0033] <First form> In the first embodiment, as shown in Figure 2, the positions of the first switching valve 510 and the second switching valve 520 are "position 0".

[0034] In the first embodiment, the mobile phase introduced from the liquid delivery unit 200 to port 516 of the first switching valve 510 is sent to the detector 600 via port 515, port 526, port 525, end 411, end 412, port 521, port 522, port 514, port 513, end 421, end 422, port 511, port 512, port 523, and port 524. As a result, in the first embodiment, the mobile phase flows forward through the first separation column 410 and the second separation column 420, as indicated by arrow A10.

[0035] <Second form> In the second configuration, as shown in Figure 3, the position of the first switching valve 510 is "position 0", and the position of the second switching valve 520 is "position 1".

[0036] In the second configuration, the mobile phase introduced from the liquid delivery unit 200 to port 516 of the first switching valve 510 is sent to the detector 600 via port 515, port 526, port 521, end 412, end 411, port 525, and port 524. As a result, in the second configuration, the mobile phase flows in the reverse direction through the first separation column 410, as indicated by arrow A20, but does not flow through the second separation column 420, as schematically shown by icon P20. In other words, in the second configuration, the second separation column 420 is disconnected from the above flow path.

[0037] <3rd form> In the third configuration, as shown in Figure 4, the position of the first switching valve 510 is "Position 1", and the position of the second switching valve 520 is "Position 0".

[0038] In the third embodiment, the mobile phase introduced from the liquid delivery unit 200 to port 516 of the first switching valve 510 is sent to the detector 600 via port 511, end 422, end 421, port 513, port 512, port 523, and port 524. As a result, in the third embodiment, the mobile phase flows in the reverse direction through the second separation column 420, as indicated by arrow A30, but no mobile phase flows through the first separation column 410, as schematically shown by icon P30. In other words, in the third embodiment, the first separation column 410 is disconnected from the above flow path.

[0039] <4th form> In the fourth configuration, as shown in Figure 5, the positions of the first switching valve 510 and the second switching valve 520 are "Position 1".

[0040] In the fourth embodiment, the mobile phase introduced from the liquid delivery unit 200 to port 516 of the first switching valve 510 is sent to the detector 600 via port 511, end 422, end 421, port 513, port 512, port 523, port 522, port 514, port 515, port 526, port 521, end 412, end 411, port 525, and port 524. As a result, in the fourth embodiment, the mobile phase flows in opposite directions through the first separation column 410 and the second separation column 420, as indicated by arrow A40.

[0041] [Process Flow] Figures 6 and 7 are flowcharts of the processes performed by the liquid chromatograph 1 for the analysis of SARA components. In one implementation example, the processes shown in Figures 6 and 7 are performed by the liquid chromatograph 1 when the processor 101 executes a given program.

[0042] First, referring to Figure 6, step S 02The liquid chromatograph 1 then determines whether or not it is time to start the analysis of the SARA components. The liquid chromatograph 1 may determine that the above timing has arrived based on whether a given operation has been performed on the operation key of the liquid chromatograph 1 (not shown), whether the liquid chromatograph 1 has received an instruction to start the analysis from an external source, and / or whether a pre-registered time has arrived.

[0043] Liquid chromatograph 1 repeatedly performs the control in step S02 until it determines that the above timing has arrived (NO in step S02). Once it determines that the above timing has arrived (YES in step S02), it proceeds to step S04.

[0044] In step S04, the liquid chromatograph 1 causes the sample (for example, a sample for the analysis of SARA components) to be injected into the sampler 300 into a flow path including the first switching valve 510 and the second switching valve 520.

[0045] In step S10, the liquid chromatograph 1 forms a first configuration (Figure 2) in a flow path including the first switching valve 510 and the second switching valve 520, causing the liquid delivery unit 200 to deliver the first mobile phase toward the first switching valve 510.

[0046] The first embodiment may be formed by the controller 100 switching the positions of the first switching valve 510 and the second switching valve 520 to "position 0". The controller 100 may also supply the first mobile phase to the liquid supply unit 200 by connecting the liquid supply pump 201 to the above-mentioned outlet.

[0047] In step S12, the liquid chromatograph 1 determines whether the first analysis time has elapsed since the start of the first mobile phase delivery (step S10). The first analysis time is a predetermined time for the analysis of the saturated portion of the SARA components. The first analysis time may be set as appropriate by the user. Information identifying the first analysis time may be stored in the storage device 102. The liquid chromatograph 1 repeats the control in step S12 until it determines that the first analysis time has elapsed (NO in step S12), and when it determines that the first analysis time has elapsed (YES in step S12), it proceeds to step S14.

[0048] In step S14, the liquid chromatograph 1 stores the detection results (first analysis results) obtained by the detector 600 in the storage device 102. In one implementation example, the first analysis results include the analysis results of the saturated component in the sample.

[0049] In step S20, the liquid chromatograph 1 forms a second configuration (Figure 3) in the flow path including the first switching valve 510 and the second switching valve 520, causing the liquid delivery unit 200 to deliver the second mobile phase toward the first switching valve 510.

[0050] The second form may be formed by the controller 100 switching the position of the first switching valve 510 to "position 0" and the position of the second switching valve 520 to "position 1". The controller 100 may also supply the second mobile phase to the liquid supply unit 200 by connecting the liquid supply pump 202 to the above-mentioned outlet.

[0051] In step S22, the liquid chromatograph 1 determines whether the second analysis time has elapsed since the start of the second mobile phase delivery (step S20). The second analysis time is a predetermined time for the analysis of the resin component of the SARA components. The second analysis time may be set as appropriate by the user. Information identifying the second analysis time may be stored in the storage device 102. The liquid chromatograph 1 repeats the control in step S22 until it determines that the second analysis time has elapsed (NO in step S22), and when it determines that the second analysis time has elapsed (YES in step S22), it proceeds to step S24.

[0052] In step S24, the liquid chromatograph 1 stores the detection results (second analysis results) obtained by the detector 600 in the storage device 102. In one implementation example, the second analysis results include the analysis results of the resin content in the sample.

[0053] Referring to Figure 7, in step S30, the liquid chromatograph 1 forms a second configuration (Figure 3) in the flow path including the first switching valve 510 and the second switching valve 520, causing the liquid delivery unit 200 to deliver the third mobile phase toward the first switching valve 510.

[0054] The controller 100 may supply the third mobile phase to the liquid supply unit 200 by connecting the liquid supply pump 203 to the aforementioned outlet.

[0055] In step S32, the liquid chromatograph 1 determines whether the third analysis time has elapsed since the start of the delivery of the third mobile phase (step S30). The third analysis time is a predetermined time for the analysis of the asphaltene component of the SARA components. The third analysis time may be set as appropriate by the user. Information identifying the third analysis time may be stored in the storage device 102. The liquid chromatograph 1 repeats the control in step S32 until it determines that the third analysis time has elapsed (NO in step S32), and when it determines that the third analysis time has elapsed (YES in step S32), it proceeds to step S34.

[0056] In step S34, the liquid chromatograph 1 stores the detection results (third analysis results) obtained by the detector 600 in the storage device 102. In one implementation example, the third analysis results include the analysis results for the asphaltene content in the sample.

[0057] In step S40, the liquid chromatograph 1 forms a third configuration (Figure 4) in the flow path including the first switching valve 510 and the second switching valve 520, causing the liquid delivery unit 200 to deliver the fourth mobile phase toward the first switching valve 510.

[0058] The third form may be formed by the controller 100 switching the position of the first switching valve 510 to "position 1" and the position of the second switching valve 520 to "position 0". The controller 100 may also supply the fourth mobile phase to the liquid supply unit 200 by connecting the liquid supply pump 204 to the above-mentioned outlet.

[0059] In step S42, the liquid chromatograph 1 determines whether the fourth analysis time has elapsed since the start of the fourth mobile phase delivery (step S40). The fourth analysis time is a predetermined time for the analysis of the aromatic component of the SARA components. The fourth analysis time may be set as appropriate by the user. Information identifying the fourth analysis time may be stored in the storage device 102. The liquid chromatograph 1 repeats the control in step S42 until it determines that the fourth analysis time has elapsed (NO in step S42), and when it determines that the fourth analysis time has elapsed (YES in step S42), it proceeds to step S44.

[0060] In step S44, the liquid chromatograph 1 stores the detection results (fourth analysis results) obtained by the detector 600 in the storage device 102. In one implementation example, the fourth analysis results include the analysis results of the aromatic components in the sample.

[0061] In step S50, the liquid chromatograph 1 forms a fourth configuration (Figure 5) in the flow path including the first switching valve 510 and the second switching valve 520, causing the liquid delivery unit 200 to send the cleaning liquid toward the first switching valve 510.

[0062] The fourth embodiment may be formed by the controller 100 switching the positions of the first switching valve 510 and the second switching valve 520 to "position 1". The controller 100 may also supply the cleaning fluid to the fluid supply unit 200 by connecting the fluid supply pump 205 to the above-mentioned outlet.

[0063] In step S52, the liquid chromatograph 1 determines whether the washing time has elapsed since the start of dispensing the washing solution (step S50). The washing time is a predetermined time for washing the first separation column 410 and the second separation column 420. The washing time may be set as appropriate by the user. Information identifying the washing time may be stored in the storage device 102. The liquid chromatograph 1 repeats the control in step S52 until it determines that the washing time has elapsed (NO in step S52), and when it determines that the washing time has elapsed (YES in step S52), it proceeds to step S54.

[0064] In step S60, the liquid chromatograph 1 stops the operation of each element. Subsequently, the liquid chromatograph 1 completes the processes shown in Figures 6 and 7.

[0065] In the liquid chromatograph 1 described above, the controller 100 combines the two states of the first switching valve 510 and the second switching valve 520 to form the first to third forms in the flow path including the first switching valve 510 and the second switching valve 520, thereby enabling SARA analysis using the first separation column 410 and the second separation column 420 in the preparative liquid chromatograph 1.

[0066] In the second configuration, the second separation column 420 is disconnected from the flow path. In the third configuration, the first separation column 410 is disconnected from the flow path. That is, during the backflushing of one of the two separation columns, the other separation column is disconnected from the flow path. In the liquid chromatograph 1, contamination is prevented, and premature deterioration of the separation columns due to pressure fluctuations is prevented.

[0067] In liquid chromatograph 1, there is no need to use a backflow prevention valve for the formation of the first to third forms. This reduces the system capacity and carryover in liquid chromatograph 1.

[0068] The controller 100 further forms a fourth configuration in the above flow path and washes the first separation column 410 and the second separation column 420 (steps S50, S52).

[0069] In the fourth configuration, the solution introduced from the liquid delivery unit 200 flows in the reverse direction through the first separation column 410 and the second separation column 420. Therefore, in the washing in steps S50 and S52, the washing solution flows in the reverse direction through the first separation column 410 and the second separation column 420. In the fourth configuration, the entire flow path is washed by backflushing, thereby suppressing cross-contamination between analyses.

[0070] Alternatively, instead of, or in addition to, the washing in steps S50 and S52, washing may be performed using the first to fourth mobile phases used for the analysis of the four components.

[0071] For example, after step S44, the liquid chromatograph 1 may flow the fourth mobile phase through the third channel, the third mobile phase through the second channel, the second mobile phase through the second channel, and then the first mobile phase through the first channel. This ensures that after the analysis of the four components, the mobile phases used for the analysis of the four components are flowed in the reverse order of the analysis. After washing using the first to fourth mobile phases, the liquid chromatograph 1 may perform further washing in steps S50 and S52.

[0072] [Pattern] Those skilled in the art will understand that the above-described exemplary embodiments are specific examples of the following embodiments.

[0073] (Section 1) A liquid chromatograph according to one embodiment includes a first column, a second column, a liquid delivery unit configured to deliver a mobile phase to at least one of the first column and the second column, a first switching valve having at least two connected states, a second switching valve connected to the first switching valve and having at least two connected states, and a configuration that, by combining one of the two connected states of the first switching valve and one of the two connected states of the second switching valve, forms a first, second, and third form in the flow path including the first and second switching valves. The system comprises a control unit, and in the first embodiment, the mobile phase from the liquid delivery unit is delivered in the order of one end of the first column, the other end of the first column, one end of the second column, and the other end of the second column; in the second embodiment, the mobile phase from the liquid delivery unit is not introduced to the first column, and the mobile phase from the liquid delivery unit is delivered from the other end of the second column to one end of the second column; and in the third embodiment, the mobile phase from the liquid delivery unit is delivered from the other end of the first column to one end of the first column, and the mobile phase from the liquid delivery unit may not be introduced to the second column.

[0074] According to the liquid chromatograph described in paragraph 1, a configuration of a liquid chromatograph that embodies a method for analyzing SARA components is provided.

[0075] (Section 2) In the liquid chromatograph described in Section 1, the first switching valve has at least two connected states, including a first state and a second state, the first state connecting the liquid delivery unit to the second switching valve and connecting the second switching valve to one end of the second column, the second state connecting the liquid delivery unit to the other end of the second column, and the second switching valve has at least two connected states, including a third state and a fourth state, the third state connecting the other end of the first column to the first switching valve and the other end of the first column The control unit may be configured to connect the first switching valve to the other end of the second column in order to form the first configuration, to set the first switching valve to the first configuration and the second switching valve to the third configuration in order to form the second configuration, to set the first switching valve to the first configuration and the second switching valve to the fourth configuration in order to form the third configuration, to set the first switching valve to the second configuration and the second switching valve to the third configuration.

[0076] The liquid chromatograph described in Section 2 provides specific states for the first and second switching valves, thereby facilitating the implementation of a method for analyzing SARA components in a liquid chromatograph.

[0077] (Clause 3) In the liquid chromatograph described in paragraph 1 or 2, the liquid delivery unit is configured to selectively deliver one of the first mobile phase, second mobile phase, third mobile phase, and fourth mobile phase as the mobile phase toward the first switching valve, and the control unit may be configured to cause the liquid delivery unit to deliver the first mobile phase toward the first switching valve when the first configuration is formed in the flow path, to cause the liquid delivery unit to deliver the second mobile phase toward the first switching valve when the second configuration is formed in the flow path, to cause the liquid delivery unit to deliver the third mobile phase toward the first switching valve when the second configuration is formed in the flow path, and to cause the liquid delivery unit to deliver the fourth mobile phase toward the first switching valve when the third configuration is formed in the flow path.

[0078] According to the liquid chromatography described in Section 3, appropriate mobile phases are delivered to the first and second columns in the analysis of SARA components.

[0079] (Clause 4) The liquid chromatograph described in any one of paragraphs 1 to 3 further comprises a detector for deriving the detection results of components of a solution, wherein in the first embodiment, the first switching valve connects the other end of the second column to the first switching valve, and the second switching valve introduces the solution introduced from the other end of the second column to the detector, in the second embodiment, the first switching valve separates the second column from the liquid delivery unit, and the second switching valve connects one end of the second column to the detector, in the third embodiment, the first switching valve connects one end of the second column to the detector, and the second switching valve separates the first column from the liquid delivery unit.

[0080] According to the liquid chromatography described in Section 4, contamination and premature column degradation due to pressure fluctuations are prevented.

[0081] (Clause 5) In the liquid chromatograph described in any one of Clauses 1 to 4, the control unit is configured to further form a fourth configuration in the flow path by combining one of the two connected states of the first switching valve and one of the two connected states of the second switching valve, in which case the mobile phase from the liquid delivery unit may be delivered from the other end of the first column to one end of the first column and from the other end of the second column to one end of the second column.

[0082] According to the liquid chromatography described in Section 5, a mobile phase flow is formed that washes the first and second columns.

[0083] (Clause 6) In the liquid chromatograph described in Clause 5, the control unit may be configured to cause the liquid delivery unit to deliver cleaning fluid toward the first switching valve when the fourth configuration is formed in the flow path.

[0084] According to the liquid chromatography described in Section 6, the first and second columns are washed with a washing solution.

[0085] (Clause 7) The liquid chromatograph described in any one of paragraphs 1 to 6 may further include a sampler provided between the liquid delivery unit and the first switching valve for supplying a sample toward the flow path.

[0086] According to the liquid chromatography described in Section 7, the sample is supplied to the first and second columns for the analysis of the SARA components.

[0087] (Clause 8) The liquid chromatograph described in any one of paragraphs 1 to 7 may have a flow path configured to send the mobile phase sent from the liquid delivery unit to the first switching valve.

[0088] According to the liquid chromatograph described in Section 8, in the analysis of SARA components, no new elements (such as valves) are required to deliver the mobile phase from the liquid delivery unit to the first switching valve, thus avoiding an increase in the manufacturing cost of the liquid chromatograph.

[0089] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope of the claims are intended to be included. [Explanation of Symbols]

[0090] 1 liquid chromatograph, 100 controller, 200 liquid delivery unit, 300 sampler, 410 first separation column, 420 second separation column, 510 first switching valve, 520 second switching valve, 600 detector.

Claims

1. The first column and, The second column and, A liquid delivery unit configured to deliver the mobile phase to at least one of the first column and the second column, A first switching valve having at least two connected states, A second switching valve connected to the first switching valve and having at least two connected states, The control unit is configured to form a first, second, and third configuration in a flow path including the first and second switching valves by combining one of the at least two connected states of the first switching valve and one of the at least two connected states of the second switching valve. In the first embodiment, the mobile phase from the liquid delivery unit is delivered in the following order: one end of the first column, the other end of the first column, one end of the second column, and the other end of the second column. In the second embodiment, the mobile phase from the liquid delivery unit is not introduced to the second column, and the mobile phase from the liquid delivery unit is delivered from the other end of the first column to one end of the first column. In the third embodiment, the mobile phase from the liquid delivery unit is delivered from the other end of the second column to one end of the second column, and the mobile phase from the liquid delivery unit is not introduced to the first column. The at least two connected states of the first switching valve include a first state and a second state, The first state is characterized by connecting the liquid delivery unit and the second switching valve, and connecting the second switching valve to one end of the second column. The second state is connected to the other end of the liquid delivery unit and the second column, The at least two connected states of the second switching valve include a third state and a fourth state, The third state is achieved by connecting the other end of the first column to the first switching valve. The fourth state is achieved by connecting the first switching valve and the other end of the second column. The control unit is To form the first embodiment, the first switching valve is set to the first state, and the second switching valve is set to the third state. To form the second embodiment, the first switching valve is set to the first state, and the second switching valve is set to the fourth state. A liquid chromatograph configured to set the first switching valve to the second state and the second switching valve to the third state in order to form the third form.

2. The first column and, The second column and, A liquid delivery unit configured to deliver the mobile phase to at least one of the first column and the second column, A first switching valve having at least two connected states, A second switching valve connected to the first switching valve and having at least two connected states, The control unit is configured to form a first, second, and third configuration in a flow path including the first and second switching valves by combining one of the at least two connected states of the first switching valve and one of the at least two connected states of the second switching valve. In the first embodiment, the mobile phase from the liquid delivery unit is delivered in the following order: one end of the first column, the other end of the first column, one end of the second column, and the other end of the second column. In the second embodiment, the mobile phase from the liquid delivery unit is not introduced to the second column, and the mobile phase from the liquid delivery unit is delivered from the other end of the first column to one end of the first column. In the third embodiment, the mobile phase from the liquid delivery unit is delivered from the other end of the second column to one end of the second column, and the mobile phase from the liquid delivery unit is not introduced to the first column. It further includes a detector that derives the detection results of the components of the solution, In the first embodiment, The first switching valve connects the other end of the second column to the first switching valve, The second switching valve introduces the solution introduced from the other end of the second column to the detector. In the second embodiment, The first switching valve separates the second column from the liquid delivery unit. The second switching valve connects one end of the first column to the detector, In the third embodiment described above, The first switching valve connects one end of the second column to the detector, The second switching valve separates the first column from the liquid delivery unit in a liquid chromatograph.

3. The first column and, The second column and, A liquid delivery unit configured to deliver the mobile phase to at least one of the first column and the second column, A first switching valve having at least two connected states, A second switching valve connected to the first switching valve and having at least two connected states, The control unit is configured to form a first, second, and third configuration in a flow path including the first and second switching valves by combining one of the at least two connected states of the first switching valve and one of the at least two connected states of the second switching valve. In the first embodiment, the mobile phase from the liquid delivery unit is delivered in the following order: one end of the first column, the other end of the first column, one end of the second column, and the other end of the second column. In the second embodiment, the mobile phase from the liquid delivery unit is not introduced to the second column, and the mobile phase from the liquid delivery unit is delivered from the other end of the first column to one end of the first column. In the third embodiment, the mobile phase from the liquid delivery unit is delivered from the other end of the second column to one end of the second column, and the mobile phase from the liquid delivery unit is not introduced to the first column. The control unit is configured to further form a fourth configuration in the flow path by combining one of the at least two connected states of the first switching valve and one of the at least two connected states of the second switching valve. In the fourth embodiment, the mobile phase from the liquid delivery unit is delivered from the other end of the first column to one end of the first column and from the other end of the second column to one end of the second column in a liquid chromatograph.

4. The liquid chromatograph according to claim 3, wherein the control unit is configured to cause the liquid delivery unit to deliver cleaning liquid toward the first switching valve when the fourth configuration is formed in the flow path.

5. The liquid transfer unit is configured to selectively send one of the first mobile phase, second mobile phase, third mobile phase, and fourth mobile phase towards the first switching valve as the mobile phase. The control unit is When the first configuration is formed in the flow path, the liquid delivery unit is instructed to send the first mobile phase toward the first switching valve. When the second configuration is formed in the flow path, the liquid delivery unit is instructed to deliver the second mobile phase toward the first switching valve, and thereafter, the liquid delivery unit is instructed to deliver the third mobile phase toward the first switching valve. A liquid chromatograph according to any one of claims 1 to 3, wherein when the third configuration is formed in the flow path, the liquid delivery unit is configured to deliver the fourth mobile phase toward the first switching valve.

6. The liquid chromatograph according to any one of claims 1 to 3, further comprising a sampler provided between the liquid delivery unit and the first switching valve for supplying a sample toward the flow path.

7. The liquid chromatograph according to any one of claims 1 to 3, wherein the flow path is configured to send the mobile phase sent from the liquid delivery unit to the first switching valve.

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