Patent Publication Number: US-2023136050-A1

Title: Method of cleaning liquid chromatographic system and liquid chromatographic system

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present disclosure relates to a method of cleaning a liquid chromatographic system and a liquid chromatographic system. 
     Description of the Background Art 
     Liquid chromatography is a technology for separating a component contained in a sample by introducing a sample to be analyzed into a column together with an eluent which is a mobile phase. The component in the sample separated by liquid chromatography is analyzed by a detector such as a mass spectrometer. 
     WO2017/216934 describes a chromatographic mass spectrometry device including a plurality of streams for a liquid chromatogram. The chromatographic mass spectrometry device described in WO2017/216934 includes three flow paths to which a column is connected. In the chromatographic mass spectrometry device described in WO2017/216934, a mass spectrometer is connected to any one of the three flow paths through a selector valve connected thereto. 
     SUMMARY OF THE INVENTION 
     According to the chromatographic mass spectrometry device described in WO2017/216934, analysis efficiency can be enhanced by continuing analysis with switching among a plurality of flow paths being made. While the sample is analyzed with switching among the plurality of flow paths being made, however, some of the sample used in preceding analyses may be accumulated as contamination in a flow path and carryover may occur in at least one of the plurality of flow paths. As the number of flow paths that can be used for analysis increases, the number of flow paths where carryover may occur also increases. When carryover occurs, an appropriate analysis result may not be obtained. Therefore, appropriate cleaning of an analysis flow path used for analysis of the sample is demanded. 
     An object of the present disclosure is to provide a method of cleaning a liquid chromatographic system and a liquid chromatographic system that allow lessening of occurrence of carryover or elimination of carryover on the occurrence of carryover. 
     A method according to one aspect of the present disclosure is a method of cleaning a liquid chromatographic system. The liquid chromatographic system includes a first column and a second column for separation of a sample, a needle that takes a sample to be injected into the first column and the second column, an injection valve portion to which the first column and the second column are connected, the injection valve portion including a first injection valve connected to the first column and a second injection valve connected to the second column, a first pump that supplies an eluent to the first injection valve, a second pump that supplies an eluent to the second injection valve, a first analysis flow path constructed such that the eluent flows from the first injection valve toward the first column, a second analysis flow path constructed such that the eluent flows from the second injection valve toward the second column, and a selector valve connected to the first column and the second column, the selector valve switching an object to be connected to a detector between the first analysis flow path and the second analysis flow path. The method of cleaning a liquid chromatographic system includes setting a condition for feeding a cleaning solution or a blank sample to the selector valve, cleaning the first analysis flow path by feeding the cleaning solution or the blank sample while a first flow path through which the eluent flows from the first injection valve to the first column via the needle is set, and cleaning the first analysis flow path by feeding the cleaning solution or the blank sample while a second flow path through which the eluent flows from the first injection valve to the first column not via the needle is set. 
     A liquid chromatographic system according to one aspect of the present disclosure includes a first column and a second column for separation of a sample, a needle that takes a sample to be injected into the first column and the second column, an injection valve portion to which the first column and the second column are connected, the injection valve portion including a first injection valve connected to the first column and a second injection valve connected to the second column, a first pump that supplies an eluent to the first injection valve, a second pump that supplies an eluent to the second injection valve, a first analysis flow path constructed such that the eluent flows from the first injection valve toward the first column, a second analysis flow path constructed such that the eluent flows from the second injection valve toward the second column, a selector valve connected to the first column and the second column, the selector valve switching an object to be connected to a detector between the first analysis flow path and the second analysis flow path, and a controller. The controller can have the first analysis flow path cleaned by feed of a cleaning solution or a blank sample while a first flow path through which the eluent flows from the first injection valve to the first column via the needle is set, and have the first analysis flow path cleaned by feed of the cleaning solution or the blank sample while a second flow path through which the eluent flows from the first injection valve to the first column not via the needle is set. 
     The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram of a schematic construction of a liquid chromatographic system. 
         FIGS.  2  and  3    are diagrams each showing a construction of the liquid chromatographic system. 
         FIG.  4    is a block diagram showing the construction of the liquid chromatographic system. 
         FIG.  5    is a diagram exemplifying a state of suction of a sample by a needle. 
         FIG.  6    is a diagram exemplifying a state of injection of the sample sucked by the needle into an injection port. 
         FIG.  7    is a diagram exemplifying a state of injection of an eluent into a column after the sample is guided to the column. 
         FIG.  8    is a diagram exemplifying a state of switching of a stream to be used for analysis from a first stream to a second stream. 
         FIG.  9    is a diagram showing a comparative example of the liquid chromatographic system according to the present embodiment. 
         FIG.  10    is a diagram for illustrating overview of a first cleaning pattern to a fifth cleaning pattern. 
         FIG.  11    is a diagram showing a specific exemplary construction of the first cleaning pattern. 
         FIG.  12    is a diagram showing a specific exemplary construction of the second cleaning pattern. 
         FIG.  13    is a diagram showing a specific exemplary construction of the third cleaning pattern. 
         FIG.  14    is a diagram showing a specific exemplary construction of the fourth cleaning pattern. 
         FIG.  15    is a diagram showing a specific exemplary construction of the fifth cleaning pattern. 
         FIG.  16    is a diagram showing an example in which a flow path is cleaned in the third cleaning pattern and the fourth cleaning pattern during suction of the sample. 
         FIG.  17    is a diagram showing an example in which the flow path is cleaned in the fourth cleaning pattern during injection of the sample. 
         FIG.  18    is a diagram showing an example in which the flow path is cleaned in the second cleaning pattern during analysis of the sample. 
         FIG.  19    is a diagram showing an example in which the flow path is cleaned in the fourth cleaning pattern and the fifth cleaning pattern during analysis of the sample. 
         FIG.  20    is a diagram showing a cleaning pattern that can be selected in first to fourth analysis flow paths. 
         FIG.  21    is a timing chart showing exemplary setting for the cleaning pattern. 
         FIG.  22    is a timing chart showing an exemplary pattern of driving a cleaning pump and a high-pressure pump. 
         FIG.  23    is a flowchart showing contents of processing performed by a controller based on the setting shown in  FIG.  21   . 
         FIG.  24    is a flowchart showing contents of processing relating to setting for the cleaning pattern. 
         FIG.  25    is a diagram showing an exemplary setting screen for automatic cleaning. 
         FIG.  26    is a flowchart showing contents of processing for cleaning the analysis flow path in accordance with a status of occurrence of carryover. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An embodiment of the present disclosure will be described in detail below with reference to the drawings. The same or corresponding elements in the drawings have the same reference characters allotted and description thereof will not be repeated. 
     &lt;Overall Construction&gt; 
       FIG.  1    is a diagram of a schematic construction of a liquid chromatographic system  10 . In liquid chromatographic system  10 , flow paths  291 A to  291 D used for analysis of a sample are provided. Flow paths  291 A to  291 D include high-pressure valves  180 A to  180 D, respectively. Flow paths  291 A to  291 D are connected to a flow path  292  which leads to a detector  500 . 
     A diverter valve  90  is arranged between flow paths  291 A to  291 D and flow path  292 . 
     Flow paths  291 A to  291 D are each switched between a first flow path which leads to diverter valve  90  via a sample injection device  100  and a second flow path which leads to diverter valve  90  not via sample injection device  100 . Sample injection device  100  includes a needle for injection of a sample. 
     Diverter valve  90  includes ports  91  to  97 . Flow path  291 A is connected to port  91 . Flow path  291 B is connected to port  92 . Flow path  291 C is connected to port  93 . Flow path  291 D is connected to port  94 . Detector  500  is connected to port  95 . A liquid discharge pipe (not shown) is connected to ports  96  and  97 . Port  95  corresponds to a main port. Ports  96  and  97  correspond to a drain port. 
     Diverter valve  90  implements a selector valve that switches an object to be connected to port  95  among ports  91  to  94 . Through diverter valve  90 , any one of flow paths  291 A to  291 D is connected to flow path  292  which leads to detector  500 . 
     A construction of flow path  291 A will be described in detail. 
     Flow path  291 A is a flow path that includes high-pressure valve  180 A and extends from high-pressure valve  180 A in a direction toward a column  230 A. Flow path  291 A is switched by high-pressure valve  180 A between the first flow path which leads to column  230 A via sample injection device  100  and the second flow path which leads to column  230 A not via sample injection device  100 . 
     In flow path  291 A, at least a high-pressure pump  220 A, a cleaning pump  143 A, a cleaning valve  18 A, high-pressure valve  180 A, and column  230 A are arranged. High-pressure valve  180 A is connected to column  230 A. Column  230 A is filled with a stationary phase for separating a component in a sample. 
     High-pressure valve  180 A is connected to high-pressure pump  220 A and cleaning pump  143 A with cleaning valve  18 A being interposed. High-pressure pump  220 A supplies an eluent in a container  210 A to high-pressure valve  180 A. Cleaning pump  143 A supplies a rinse solution in a container  250 A to high-pressure valve  180 A. Any one of high-pressure pump  220 A and cleaning pump  143 A is connected to high-pressure valve  180 A through cleaning valve  18 A. Consequently, the eluent or the rinse solution is supplied to high-pressure valve  180 A. 
     When flow path  291 A is set to the first flow path that passes through sample injection device  100 , the eluent supplied from high-pressure pump  220 A to high-pressure valve  180 A flows to column  230 A via sample injection device  100 . The sample held in sample injection device  100  is sent to column  230 A over the eluent. 
     When flow path  291 A is set to the second flow path that does not pass through sample injection device  100 , the eluent supplied from high-pressure pump  220 A to high-pressure valve  180 A flows to column  230 A without passing through sample injection device  100 . When the sample has already been injected into column  230 A, the eluent is sent from high-pressure valve  180 A to column  230 A through the second flow path. Separation of the sample in column  230 A thus proceeds. 
     Column  230 A is connected to port  91  of diverter valve  90 . When port  91  and port  95  are connected to each other in diverter valve  90 , a component in the sample separated in column  230 A flows to detector  500  via diverter valve  90 . Consequently, the component in the sample separated in column  230 A is analyzed by detector  500  implemented by a mass spectrometer or the like. 
     When cleaning pump  143 A and high-pressure valve  180 A are connected to each other through cleaning valve  18 A, the rinse solution is supplied to high-pressure valve  180 A. High-pressure valve  180 A can allow a flow of the rinse solution to column  230 A through or not through sample injection device  100 . Thus, both of the first flow path leading to column  230 A via sample injection device  100  and the second flow path leading to column  230 A not via sample injection device  100  can be cleaned. 
     When port  91  and port  95  of diverter valve  90  are connected to each other, the rinse solution flows from column  230 A to detector  500  via port  91  and port  95  of diverter valve  90 . Consequently, flow path  292  leading from diverter valve  90  toward detector  500  is also cleaned. When port  91  and ports  96  and  97  of diverter valve  90  are connected to each other, port  91  and ports  96  and  97  of the diverter valve are cleaned. 
     The construction of flow path  291 A is described above in detail. The construction of flow paths  291 B to  291 D will now be described. 
     Flow path  291 B is a flow path that includes high-pressure valve  180 B and extends from high-pressure valve  180 B in a direction toward column  230 B. Flow path  291 B is switched by high-pressure valve  180 B between the first flow path which leads to column  230 B via sample injection device  100  and the second flow path which leads to column  230 B not via sample injection device  100 . 
     In flow path  291 B, at least a high-pressure pump  220 B that sucks an eluent from a container  210 B, a cleaning pump  143 B that sucks a rinse solution from a container  250 B, a cleaning valve  18 B, high-pressure valve  180 B, and column  230 B are arranged. 
     Flow path  291 C is a flow path that includes high-pressure valve  180 C and extends from high-pressure valve  180 C in a direction toward column  230 C. Flow path  291 C is switched by high-pressure valve  180 C between the first flow path which leads to column  230 C via sample injection device  100  and the second flow path which leads to column  230 C not via sample injection device  100 . 
     In flow path  291 C, at least a high-pressure pump  220 C that sucks an eluent from a container  210 C, a cleaning pump  143 C that sucks a rinse solution from a container  250 C, a cleaning valve  18 C, high-pressure valve  180 C, and column  230 C are arranged. 
     Flow path  291 D is a flow path that includes high-pressure valve  180 D and extends from high-pressure valve  180 D in a direction toward column  230 D. Flow path  291 D is switched by high-pressure valve  180 D between the first flow path which leads to column  230 D via sample injection device  100  and the second flow path which leads to column  230 D not via sample injection device  100 . 
     In flow path  291 D, at least a high-pressure pump  220 D that sucks an eluent from a container  210 D, a cleaning pump  143 D that sucks a rinse solution from a container  250 D, a cleaning valve  18 D, high-pressure valve  180 D, and column  230 D are arranged. 
     Thus, flow paths  291 B to  291 D are similar in construction to flow path  291 A. Therefore, detailed description of flow path  291 A that has already been provided is applied as detailed description of flow paths  291 B to  291 D. 
     Flow path  291 A, flow path  291 B, flow path  291 C, and flow path  291 D are also referred to below as a first analysis flow path  291 A, a second analysis flow path  291 B, a third analysis flow path  291 C, and a fourth analysis flow path  291 D, respectively. First analysis flow path  291 A, second analysis flow path  291 B, third analysis flow path  291 C, and fourth analysis flow path  291 D are each switched between the first flow path which leads to diverter valve  90  via sample injection device  100  and the second flow path which leads to diverter valve  90  not via sample injection device  100 . 
     Liquid chromatographic system  10  can switch a flow path to be used for analysis among first analysis flow path  291 A, second analysis flow path  291 B, third analysis flow path  291 C, and fourth analysis flow path  291 D. Therefore, according to liquid chromatographic system  10 , detector  500  can successively analyze various samples. Consequently, liquid chromatographic system  10  can achieve improved analysis efficiency. 
     Liquid chromatographic system  10  further includes cleaning pump  143 A corresponding to first analysis flow path  291 A, cleaning pump  143 B corresponding to second analysis flow path  291 B, cleaning pump  143 C corresponding to third analysis flow path  291 C, and cleaning pump  143 D corresponding to fourth analysis flow path  291 D. Such a construction allows cleaning of the flow paths in various patterns in liquid chromatographic system  10 . 
     For example, when first analysis flow path  291 A is being used for analysis of a sample, a desired flow path among second analysis flow path  291 B, third analysis flow path  291 C, and fourth analysis flow path  291 D can be cleaned. &lt;Construction of Liquid Chromatographic System  10 &gt; 
       FIGS.  2  and  3    are diagrams each showing a construction of liquid chromatographic system  10 . In particular,  FIG.  3    shows a construction of diverter valve  90  included in liquid chromatographic system  10 . 
     As described with reference to  FIG.  1   , liquid chromatographic system  10  includes four high-pressure valves  180 A to  180 D.  FIG.  2    does not show features relating to high-pressure valve  180 C among four high-pressure valves  180 A to  180 D shown in  FIG.  1   . 
     High-pressure valves  180 A to  180 D are connected to a first selector valve  150  and a second selector valve  160 . First selector valve  150  and second selector valve  160  perform a function to select a high-pressure valve involved with suction and injection of a sample among high-pressure valves  180 A to  180 D. First selector valve  150  and second selector valve  160  are each implemented, for example, by a multi-way selector valve. 
     First selector valve  150  is connected to a needle valve  260 . Needle valve  260  is connected to a needle  191  with a sample loop  192  being interposed. Needle  191  is a component like a syringe needle for sucking a sample. Sample loop  192  holds a sample sucked by needle  191 . A needle moving mechanism  190  moves needle  191  in each of directions along three axes orthogonal to one another. Liquid chromatographic system  10  includes injection ports  198 A to  198 D. 
     Injection port  198 A is provided in correspondence with high-pressure valve  180 A. Injection port  198 B is provided in correspondence with high-pressure valve  180 B. Injection port  198 C is provided in correspondence with high-pressure valve  180 C. Injection port  198 D is provided in correspondence with high-pressure valve  180 D. 
     Containers  302 A to  302 C where samples are accommodated are placed on a sample carrier  300 . Needle moving mechanism  190  moves needle  191  for suction of the sample from one of containers  302 A to  302 C. Needle moving mechanism  190  moves needle  191  for injection of the sucked sample into one of injection ports  198 A to  198 D. 
     A needle cleaning pump  20  is further connected to needle valve  260 . 
     Second selector valve  160  is connected to a low-pressure valve  170 . Low-pressure valve  170  is connected to a metering pump  130 . Metering pump  130  is used for suction of a prescribed amount of sample by needle  191 . 
     High-pressure valve  180 A includes ports  181 A to  186 A. Port  181 A is connected to a not-shown liquid discharge pipe. In other words, port  181 A is a drain port. Port  182 A is connected to injection port  198 A. Port  183 A is connected to column  230 A. Port  184 A is connected to high-pressure pump  220 A and cleaning pump  143 A with cleaning valve  18 A being interposed. Port  185 A is connected to first selector valve  150 . Port  186 A is connected to second selector valve  160 . 
     High-pressure valve  180 A includes connection portions  187 A to  189 A. Connection portions  187 A to  189 A switch a state of connection of ports  181 A to  186 A between a first state and a second state. 
     The first state is a state shown in  FIG.  2   . Specifically, the first state is a state in which port  181 A and port  182 A are connected to each other, port  183 A and port  184 A are connected to each other, and port  185 A and port  186 A are connected to each other. 
     In the first state, first selector valve  150  and second selector valve  160  are connected to each other with high-pressure valve  180 A being interposed. In the first state, column  230 A and high-pressure pump  220 A or cleaning pump  143 A are connected to each other with high-pressure valve  180 A being interposed. In the first state, injection port  198 A is connected to port  181 A which is the drain port of high-pressure valve  180 A. 
     The second state is a state resulting from turning of connection portions  187 A to  189 A shown in  FIG.  1    by thirty degrees around the center of high-pressure valve  180 A. Specifically, the second state is a state in which port  182 A and port  183 A are connected to each other, port  184 A and port  185 A are connected to each other, and port  186 A and port  181 A are connected to each other. The second state is shown, for example, in  FIG.  6   . 
     High-pressure valves  180 B to  180 D are similar in construction to high-pressure valve  180 A. High-pressure valves  180 B to  180 D are each switched between the first state and the second state similarly to high-pressure valve  180 A. Further description of high-pressure valves  180 B to  180 D is substantially repetition of the description of the construction of high-pressure valve  180 A. Therefore, further description of high-pressure valves  180 A to  180 D will not be repeated. 
     First selector valve  150  includes ports  151  to  155 . High-pressure valve  180 A is connected to port  151 . High-pressure valve  180 B is connected to port  152 . High-pressure valve  180 C is connected to port  153 . High-pressure valve  180 D is connected to port  154 . Needle valve  260  is connected to port  155 . 
     First selector valve  150  includes a connection portion  158 . Connection portion  158  switches an object to be connected to port  155  among ports  151  to  154 . 
     Needle valve  260  includes ports  261  to  266  and connection portions  267  to  269 . First selector valve  150  is connected to port  261 . Sample loop  192  is connected to port  262 . Needle cleaning pump  20  is connected to port  263 . 
     Needle valve  260  switches a state of connection portions  267  to  269  between the state shown in  FIG.  2    and a state resulting from turning of connection portions  267  to  269  by thirty degrees around the center of needle valve  260  from the state shown in  FIG.  2   . 
     In the state shown in  FIG.  2   , needle  191  is connected to needle valve  260  with sample loop  192  being interposed, needle valve  260  is connected to first selector valve  150 , and first selector valve  150  is connected to high-pressure valve  180 A. Furthermore, high-pressure valve  180 A is connected to second selector valve  160 , and second selector valve  160  is connected to metering pump  130  with low-pressure valve  170  being interposed. Therefore, as needle  191  is moved to any one of containers  302 A to  302 C and then metering pump  130  is driven, needle  191  sucks the sample. 
     As shown in  FIG.  3   , columns  230 A to  230 D are connected to diverter valve  90 .  FIG.  3    shows a state that port  95  formed at the center of diverter valve  90  and port  91  corresponding to column  230 A are connected to each other. At this time, ports  92  to  94  of diverter valve  90  are connected to ports  96  and  97  which are drain ports of diverter valve  90 . 
     In this state, the flow path including column  230 A is connected to detector  500 . Detector  500  can analyze the sample in column  230 A. The flow path including column  230 B leads to a not-shown liquid discharge pipe through ports  96  and  97  of diverter valve  90 . The flow path including column  230 C and the flow path including column  230 D also similarly lead to the not-shown liquid discharge pipe through ports  96  and  97  of diverter valve  90 . 
     As described above, liquid chromatographic system  10  includes a large number of valves. In relation with first selector valve  150  and second selector valve  160 , diverter valve  90  can also be referred to as a third selector valve and needle valve  260  can also be referred to as a fourth selector valve. 
     &lt;Block Diagram of Liquid Chromatographic System  10 &gt; 
       FIG.  4    is a block diagram showing the construction of liquid chromatographic system  10 . As described so far, liquid chromatographic system  10  includes a large number of valves and a large number of pumps. 
     The valves provided in liquid chromatographic system  10  include low-pressure valve  170 , high-pressure valves  180 A to  180 D, cleaning valves  18 A to  18 D, needle valve  260 , first selector valve  150 , second selector valve  160 , and diverter valve  90 . 
     Since the specific construction of these valves has already been described with reference to  FIGS.  1  to  3   , description thereof will not be repeated. 
     The pumps provided in liquid chromatographic system  10  include high-pressure pumps  220 A to  220 D, cleaning pumps  143 A to  143 D, needle cleaning pump  20 , and metering pump  130 . High-pressure pumps  220 A to  220 D suck the eluent from containers  210 A to  210 D, respectively. Cleaning pumps  143 A to  143 D suck the rinse solution from containers  250 A to  250 D, respectively. 
     An identical eluent may be accommodated in containers  210 A to  210 D, or different types of eluents may be accommodated in containers  210 A to  210 D, respectively. An identical rinse solution may be accommodated in containers  250 A to  250 D, or different types of rinse solutions may be accommodated in containers  250 A to  250 D, respectively. 
     Needle cleaning pump  20  sucks the rinse solution from a container  200 . A rinse solution identical to the rinse solution accommodated in containers  250 A to  250 D may be accommodated in container  200 , or a rinse solution different in type from the rinse solution accommodated in containers  250 A to  250 D may be accommodated in container  200 . 
     Sample injection device  100  includes first selector valve  150 , needle valve  260 , needle  191 , and sample loop  192 . 
     Liquid chromatographic system  10  further includes a controller  110 , an input device  120 , a display device  125 , and needle moving mechanism  190 . Since details of needle moving mechanism  190  have already been described with reference to  FIG.  2   , description thereof will not be repeated. 
     Controller  110  includes a processor  111  and a memory  112 . Processor  111  is typically a computing processing unit such as a central processing unit (CPU) or a multi-processing unit (MPU). Processor  111  performs processing of liquid chromatographic system  10  by reading and executing a program stored in memory  112 . 
     Memory  112  is implemented by a non-volatile memory such as a random access memory (RAM), a read only memory (ROM), and a flash memory. So long as a program can be recorded in a non-transitory manner in a format readable by processor  111 , memory  112  may be implemented by a compact disc-read only memory (CD-ROM), a digital versatile disk-read only memory (DVD-ROM), a universal serial bus (USB) memory, a memory card, a flexible disk (FD), a hard disk, a solid state drive (SSD), a magnetic tape, a cassette tape, a magnetic optical disc (MO), a mini disc (MD), an integrated circuit (IC) card (except for a memory card), an optical card, a mask ROM, or an EPROM. 
     Input device  120  is implemented, for example, by a keyboard and a mouse. A user can input various instructions to controller  110  by operating input device  120 . An image in accordance with a video signal outputted from controller  110  is shown on display device  125 . 
     Setting information for each of first analysis flow path  291 A to fourth analysis flow path  291 D (see  FIG.  1   ) provided in liquid chromatographic system  10  is shown on display device  125 . The user can set a schedule for analysis with the use of first analysis flow path  291 A to fourth analysis flow path  291 D while the user looks at a screen on display device  125 . Controller  110  conducts analysis based on the inputted schedule and has first analysis flow path  291 A to fourth analysis flow path  291 D cleaned. 
     &lt;Suction of Sample&gt; 
       FIG.  5    is a diagram exemplifying a state of suction of a sample by needle  191 . An example of suction of a sample to be injected into injection port  198 A by needle  191  from container  302 A will be described. 
     Injection port  198 A corresponds to high-pressure valve  180 A among high-pressure valves  180 A to  180 D. Therefore, first selector valve  150  and second selector valve  160  are connected to high-pressure valve  180 A. As illustrated, first selector valve  150  is connected to needle  191  with needle valve  260  and sample loop  192  being interposed. Needle moving mechanism  190  guides needle  191  to container  302 A. Second selector valve  160  is connected to metering pump  130  with low-pressure valve  170  being interposed. 
     Metering pump  130  applies a prescribed negative pressure to needle  191  with low-pressure valve  170 , second selector valve  160 , first selector valve  150 , and needle valve  260  being interposed. Needle  191  thus sucks a prescribed amount of sample from container  302 A. The sample sucked by needle  191  is held, for example, around sample loop  192 . 
       FIG.  5    shows an example in which the sample is sucked via high-pressure valve  180 A. As an object to which first selector valve  150  and second selector valve  160  are connected is switched among high-pressure valves  180 B to  180 D, the sample is sucked via corresponding one of high-pressure valves  180 B to  180 D. 
     First selector valve  150  and second selector valve  160  implement a switching device that switches a high-pressure valve through which the flow path leading from metering pump  130  to needle  191  passes, among high-pressure valves  180 A to  180 D. 
     &lt;Injection of Sample&gt; 
       FIG.  6    is a diagram exemplifying a state of injection of the sample sucked by needle  191  into injection port  198 A. 
     In injection of the sample into injection port  198 A, connection portions  187 A to  189 A are turned by thirty degrees around the center of high-pressure valve  180 A from the state shown in  FIG.  5   . High-pressure valve  180 A and high-pressure pump  220 A are connected to each other through cleaning valve  18 A. Needle moving mechanism  190  moves needle  191  to injection port  198 A. 
     Consequently, the flow path from high-pressure pump  220 A via high-pressure valve  180 A, first selector valve  150 , needle  191 , injection port  198 A, and high-pressure valve  180 A to column  230 A is formed. This flow path corresponds to the first flow path that passes through sample injection device  100  in first analysis flow path  291 A as described with reference to  FIG.  1   . At this time, column  230 A is connected to detector  500  with diverter valve  90  being interposed.  FIG.  6    does not show a state of connection between column  230 A and diverter valve  90 . The state of connection is as shown, for example, in  FIG.  3   . 
     As high-pressure pump  220 A is driven while the flow path is formed as above, the eluent is supplied to high-pressure valve  180 A. The eluent supplied to high-pressure valve  180 A flows in a direction toward needle  191  via first selector valve  150  and the like. The sample held around sample loop  192  is thus injected together with the eluent from a tip end of needle  191  into injection port  198 A. The injected sample flows to column  230 A together with the eluent. 
       FIG.  6    shows an example in which the sample is injected into injection port  198 A corresponding to high-pressure valve  180 A. As an object to which first selector valve  150  is connected is switched among high-pressure valves  180 B to  180 D, the sample is injected into corresponding one of injection ports  198 B to  198 D corresponding to respective high-pressure valves  180 B to  180 D. 
     &lt;Injection of Eluent&gt; 
       FIG.  7    is a diagram exemplifying a state of injection of an eluent into column  230 A after the sample is guided to column  230 A. 
     After the sample is guided to column  230 A, connection portions  187 A to  189 A are turned by thirty degrees around the center of high-pressure valve  180 A from the state shown in  FIG.  6   . High-pressure pump  220 A is thus connected to column  230 A through port  184 A and port  183 A of high-pressure valve  180 A. 
     This flow path corresponds to the second flow path that does not pass through sample injection device  100  in first analysis flow path  291 A as described with reference to  FIG.  1   . At this time, column  230 A is connected to detector  500  with diverter valve  90  being interposed. The state of connection is as shown, for example, in  FIG.  3   . As the eluent is supplied from high-pressure pump  220 A to high-pressure valve  180 A, the sample is separated in column  230 A. 
     At this time, injection port  198 A is connected to port  181 A which is the drain port of high-pressure valve  180 A. Furthermore, connection portions  267  to  269  of needle valve  260  are turned by thirty degrees around the center of needle valve  260  from the state shown in  FIG.  6   . Consequently, needle cleaning pump  20  is connected to needle  191  with needle valve  260  and sample loop  192  being interposed. 
       FIG.  7    shows an example in which the eluent is injected into column  230 A. As high-pressure pumps  220 B to  220 D corresponding to respective high-pressure valves  180 B to  180 D are driven, the eluent is similarly injected into respective columns  230 B to  230 D. 
     &lt;Switching of Analysis Flow Path&gt; 
       FIG.  8    is a diagram exemplifying a state of switching of a flow path to be used for analysis of a sample from first analysis flow path  291 A to second analysis flow path  291 B. The concept of first analysis flow path  291 A and second analysis flow path  291 B is as described with reference to  FIG.  1   . 
     When the flow path to be used for analysis of the sample is switched from first analysis flow path  291 A to second analysis flow path  291 B, the state of first selector valve  150  and second selector valve  160  changes. Specifically, connection portion  158  of first selector valve  150  switches an object to which port  155  is connected from port  151  to port  152 . Connection portion  168  of second selector valve  160  switches an object to which port  167  is connected from port  161  to port  162 . 
     First selector valve  150  and second selector valve  160  are thus connected to high-pressure valve  180 B. As illustrated, first selector valve  150  is connected to needle  191  with needle valve  260  and sample loop  192  being interposed. Second selector valve  160  is connected to metering pump  130  with low-pressure valve  170  being interposed. 
     For example, after needle  191  is moved to any one of containers  302 A to  302 C where the samples are accommodated, controller  110  has metering pump  130  driven. The sample can thus be sucked by needle  191  via high-pressure valve  180 B. Injection port  198 B corresponds to high-pressure valve  180 B among high-pressure valves  180 A to  180 D. Therefore, by injection of the sample sucked by needle  191  into injection port  198 B, the sample can be guided to column  230 B corresponding to second analysis flow path  291 B. 
     &lt;Construction in Comparative Example&gt; 
       FIG.  9    is a diagram showing a comparative example of liquid chromatographic system  10  according to the present embodiment. The comparative example includes a plurality of high-pressure valves  1800 A to  1800 F, a first selector valve  1500 , a second selector valve  1600 , and a low-pressure valve  1700 . 
     First selector valve  1500  and second selector valve  1600  are in coordination, and connected to any one of high-pressure valves  1800 A to  1800 F. Low-pressure valve  1700  is connected to any one of high-pressure valves  1800 A to  1800 F with second selector valve  1600  being interposed. 
     In the comparative example, a cleaning pump corresponding to each of high-pressure valves  1800 A to  1800 F is not provided, but a cleaning pump  1400  corresponding to low-pressure valve  1700  is provided. As cleaning pump  1400  is driven, the rinse solution is supplied to second selector valve  1600  via low-pressure valve  1700 . In the comparative example, as cleaning pump  1400  is driven while first selector valve  1500  and second selector valve  1600  are connected to high-pressure valve  1800 A, a flow path including high-pressure valve  1800 A can be cleaned. 
     A flow path including high-pressure valve  1800 B, however, cannot be cleaned while first selector valve  1500  and second selector valve  1600  are connected to high-pressure valve  1800 A. Similarly, flow paths including respective high-pressure valves  1800 C to  1800 F cannot be cleaned while first selector valve  1500  and second selector valve  1600  are connected to high-pressure valve  1800 A. 
     While first selector valve  1500  and second selector valve  1600  are connected to high-pressure valve  1800 A, a sample may be being analyzed through the flow path including high-pressure valve  1800 A. At this time, the flow paths including respective high-pressure valves  1800 B to  1800 F are not being used for analysis of the sample. In the comparative example, however, an object to which the rinse solution from cleaning pump  1400  is supplied is limited to an object to which second selector valve  1600  is connected. Therefore, in the comparative example, while second selector valve  1600  is connected to high-pressure valve  1800 A, flow paths including respective high-pressure valves  1800 B to  1800 F cannot be cleaned. 
     In contrast, liquid chromatographic system  10  according to the present embodiment includes cleaning pumps  143 A to  143 D corresponding to respective high-pressure valves  180 A to  180 D. Therefore, according to liquid chromatographic system  10 , the flow paths including respective high-pressure valves  180 A to  180 D can be cleaned with the rinse solution without liquid chromatographic system  10  being affected by to which of high-pressure valves  180 A to  180 D second selector valve  160  is connected. 
     &lt;Overview of First Cleaning Pattern to Fifth Cleaning Pattern&gt; 
       FIG.  10    is a diagram for illustrating overview of a first cleaning pattern to a fifth cleaning pattern. A cleaning pattern is described with reference to  FIG.  10   , with a flow path including high-pressure valve  180 A being focused on. Liquid chromatographic system  10  can clean the flow path including high-pressure valve  180 A in the first cleaning pattern to the fifth cleaning pattern shown in  FIG.  10   . 
     In the first cleaning pattern and the second cleaning pattern, the flow path including high-pressure valve  180 A is set as in an upper left frame. A solid arrow in diverter valve  90  represents a flow path set as the first cleaning pattern and a dashed arrow in diverter valve  90  represents a flow path set as the second cleaning pattern. 
     In the first cleaning pattern and the second cleaning pattern, the rinse solution supplied from cleaning pump  143 A to high-pressure valve  180 A flows sequentially through high-pressure valve  180 A, first selector valve  150 , needle valve  260 , sample loop  192 , needle  191 , high-pressure valve  180 A, column  230 A, and diverter valve  90 . 
     The flow path for cleaning set as the first cleaning pattern and the second cleaning pattern corresponds to the first flow path that passes through needle valve  260 , sample loop  192 , and needle  191 . The first flow path represents, for example, one form of first analysis flow path  291 A. 
     In the first cleaning pattern, port  91  and port  95  of diverter valve  90  are connected to each other, and hence the rinse solution that flows into diverter valve  90  flows through ports  91  and  95  and cleans the ports inclusive of the flow path leading from diverter valve  90  to detector  500 . In the second cleaning pattern, port  91  and ports  96  and  97  of diverter valve  90  are connected to each other, and hence the rinse solution that flows into diverter valve  90  cleans port  91  and is discharged from ports  96  and  97 . 
     In the third cleaning pattern and the fourth cleaning pattern, the flow path including high-pressure valve  180 A is set as shown in a lower left frame. A solid arrow in diverter valve  90  represents the flow path set as the third cleaning pattern and a dashed arrow in diverter valve  90  represents the flow path set as the fourth cleaning pattern. 
     In the third cleaning pattern and the fourth cleaning pattern, the rinse solution supplied from cleaning pump  143 A to high-pressure valve  180 A flows sequentially through high-pressure valve  180 A, column  230 A, and diverter valve  90 . 
     The flow path for cleaning set as the third cleaning pattern and the fourth cleaning pattern corresponds to the second flow path that does not pass through needle valve  260 , sample loop  192 , and needle  191 . The second flow path represents, for example, one form of first analysis flow path  291 A. 
     In the third cleaning pattern, port  91  and port  95  of diverter valve  90  are connected to each other, and hence the rinse solution that flows into diverter valve  90  flows through ports  91  and  95  and cleans the ports inclusive of the flow path leading from diverter valve  90  to detector  500 . In the fourth cleaning pattern, port  91  and ports  96  and  97  of diverter valve  90  are connected to each other, and hence the rinse solution that flows into diverter valve  90  cleans port  91  and is discharged from ports  96  and  97 . 
     In the fifth cleaning pattern, the flow path including high-pressure valve  180 A is set as shown in a right frame. In the fifth cleaning pattern, the rinse solution supplied from needle cleaning pump  20  to needle valve  260  flows sequentially through needle valve  260 , sample loop  192 , needle  191 , and high-pressure valve  180 A. The rinse solution that has flowed into high-pressure valve  180 A is discharged from port  181 A of high-pressure valve  180 A. 
     A specific construction of the first to fifth cleaning patterns will now be described. The construction of the flow path including high-pressure valve  180 A will representatively be described below. 
     &lt;First Cleaning Pattern and Second Cleaning Pattern&gt; 
       FIG.  11    is a diagram showing a specific exemplary construction of the first cleaning pattern.  FIG.  12    is a diagram showing a specific exemplary construction of the second cleaning pattern.  FIGS.  11  and  12    do not show some of features and shows features involved with diverter valve  90  as being surrounded with a frame, which is also applicable to  FIGS.  13  to  19   . 
     In the first cleaning pattern, for example, a flow path shown in  FIG.  11    is set. Specifically, port  151  and port  155  of first selector valve  150  are connected to each other. Needle  191  is connected to injection port  198 A. In high-pressure valve  180 A, port  182 A and port  183 A are connected to each other, port  184 A and port  185 A are connected to each other, and port  186 A and port  181 A are connected to each other. In diverter valve  90 , port  91  and port  95  are connected to each other. 
     As the rinse solution is supplied from cleaning pump  143 A to high-pressure valve  180 A, the flow path including high-pressure valve  180 A, first selector valve  150 , needle valve  260 , sample loop  192 , needle  191 , injection port  198 A, high-pressure valve  180 A, column  230 A, and diverter valve  90  is cleaned with the rinse solution. Furthermore, the flow path leading to detector  500  is cleaned with the rinse solution. At this time, a container for a blank sample such as the rinse solution or the eluent may be prepared at sample carrier  300 , the blank sample may be sucked by needle  191 , and cleaning in the first cleaning pattern may be performed. 
     In the second cleaning pattern, for example, a flow path shown in  FIG.  12    is set. The second cleaning pattern is different from the first cleaning pattern in setting of the flow path in diverter valve  90 . Specifically, in the second cleaning pattern, port  91  and ports  96  and  97  of diverter valve  90  are connected to each other. Therefore, in the second cleaning pattern, the flow path leading from port  91  to ports  96  and  97  of diverter valve  90  is cleaned. At this time, a container for a blank sample such as the rinse solution or the eluent may be prepared at sample carrier  300 , the blank sample may be sucked by needle  191 , and cleaning in the second cleaning pattern may be performed. 
     &lt;Third Cleaning Pattern and Fourth Cleaning Pattern&gt; 
       FIG.  13    is a diagram showing a specific exemplary construction of the third cleaning pattern.  FIG.  14    is a diagram showing a specific exemplary construction of the fourth cleaning pattern. 
     In the third cleaning pattern, for example, a flow path shown in  FIG.  13    is set. Specifically, port  181 A and port  182 A of high-pressure valve  180 A are connected to each other, port  183 A and port  184 A are connected to each other, and port  185 A and port  186 A are connected to each other. In diverter valve  90 , port  91  and port  95  are connected to each other. 
     The rinse solution supplied from cleaning pump  143 A to high-pressure valve  180 A flows to column  230 A without flowing to needle  191 . Consequently, diverter valve  90  and the flow path leading from diverter valve  90  to detector  500  are cleaned with the rinse solution. 
     In the fourth cleaning pattern, for example, a flow path shown in  FIG.  14    is set. The fourth cleaning pattern is different from the third cleaning pattern in setting of the flow path in diverter valve  90 . Specifically, in the fourth cleaning pattern, port  91  and ports  96  and  97  of diverter valve  90  are connected to each other. Therefore, in the fourth cleaning pattern, the flow path leading from port  91  to ports  96  and  97  of diverter valve  90  is cleaned. 
     &lt;Fifth Cleaning Pattern&gt; 
       FIG.  15    is a diagram showing a specific exemplary construction of the fifth cleaning pattern. 
     In the fifth cleaning pattern, for example, a flow path shown in  FIG.  15    is set. Specifically, port  262  and port  263  of needle valve  260  are connected to each other, port  264  and port  265  are connected to each other, and port  266  and port  261  are connected to each other. Port  181 A and port  182 A of high-pressure valve  180 A are connected to each other, port  183 A and port  184 A are connected to each other, and port  185 A and port  186 A are connected to each other. 
     As the rinse solution is supplied from needle cleaning pump  20  to needle valve  260 , the flow path including sample loop  192 , needle  191 , injection port  198 A, and high-pressure valve  180 A is cleaned with the rinse solution. At this time, a container for a blank sample such as the rinse solution or the eluent may be prepared at sample carrier  300 , the blank sample may be sucked by needle  191 , and cleaning in the fifth cleaning pattern may be performed. 
     As described above, according to the first cleaning pattern and the second cleaning pattern, not only the flow path from column  230 A to diverter valve  90  but also the flow path including needle  191  and sample loop  192  can be cleaned. 
     The third cleaning pattern and the fourth cleaning pattern are smaller in range of cleaning than the first cleaning pattern and the second cleaning pattern. Not including needle  191  and sample loop  192  in the third cleaning pattern and the fourth cleaning pattern, however, produces an effect of increase in variation of the cleaning method. Specifically, by making use of the third cleaning pattern and the fourth cleaning pattern, the flow path can be cleaned at timing of suction of the sample into needle  191  and sample loop  192 . 
     According to the first cleaning pattern and the third cleaning pattern, the flow path leading to detector  500 , inclusive of port  95  of diverter valve  90 , can be cleaned. 
     Such a cleaning pattern is effective, for example, in an example in which a sample at a high concentration is analyzed or in a construction in which analysis can continue with switching among a plurality of analysis flow paths (first analysis flow path  291 A to fourth analysis flow path  291 D) being made as in liquid chromatographic system  10  according to the present embodiment. 
     When analysis continues with switching among a plurality of analysis flow paths being made, a component in the sample may be accumulated in diverter valve  90  that switches among the analysis flow paths. In particular, the component in the sample may repeatedly be accumulated at port  95  in diverter valve  90  to which detector  500  is connected and carryover may occur. Alternatively, since the sample is continuously sent to an interface portion of detector  500  through diverter valve  90 , carryover may occur in that interface portion. 
     According to the first cleaning pattern and the third cleaning pattern, port  95  of diverter valve  90 , inclusive of the interface portion of detector  500 , can be cleaned. Therefore, while efficient analysis through a plurality of analysis flow paths is conducted, a portion which will be a factor for occurrence of carryover can sufficiently be cleaned. 
     An example in which the flow path is cleaned with the rinse solution is described with reference to  FIGS.  10  to  15   . In the first to fifth cleaning patterns, however, the flow path may be cleaned with the eluent (blank solution). For example, with the use of high-pressure pump  220 A instead of cleaning pump  143 A in the first to fourth cleaning patterns, cleaning with the eluent may be performed. In the fifth cleaning pattern, by connection of needle cleaning pump  20  to the container where the eluent is accommodated, cleaning with the eluent may be performed. Furthermore, in the first to fifth cleaning patterns, cleaning with the rinse solution and the eluent as being combined may be performed. For example, after the flow path is cleaned with the rinse solution, the flow path may be cleaned with the eluent. 
     The first to fifth cleaning patterns are described with reference to the example in which the flow path includes high-pressure valve  180 A. In liquid chromatographic system  10 , however, the flow paths including respective high-pressure valves  180 B to  180 D can naturally be cleaned similarly in the first to fifth cleaning patterns. The description above is similarly applicable also to the flow paths including respective high-pressure valves  180 B to  180 D. 
     An example in which the flow path defined in liquid chromatographic system  10  is cleaned in various cleaning patterns while a sample is being analyzed or preparation for analysis is being made in one of first analysis flow path  291 A to fourth analysis flow path  291 D will now be described with reference to  FIGS.  16  to  19   . 
     &lt;Example of Cleaning During Suction of Sample&gt; 
       FIG.  16    is a diagram showing an example in which a flow path is cleaned in the third cleaning pattern and the fourth cleaning pattern during suction of the sample. In particular, an example in which, during suction of the sample, first analysis flow path  291 A is cleaned in the third cleaning pattern and second analysis flow path  291 B is cleaned in the fourth cleaning pattern will be described. 
     In  FIG.  16   , first selector valve  150  and second selector valve  160  are connected to high-pressure valve  180 A. In diverter valve  90 , port  91  leading to column  230 A and port  95  leading to detector  500  are connected to each other. Therefore, the sample is ready for analysis through first analysis flow path  291 A including high-pressure valve  180 A. 
     Metering pump  130  is connected to needle  191  with low-pressure valve  170 , second selector valve  160 , high-pressure valve  180 A, first selector valve  150 , and needle valve  260  being interposed. Needle  191  is guided to container  302 A where the sample is accommodated. Needle  191  sucks the sample from container  302 A by application of a negative pressure by metering pump  130 . 
     In high-pressure valve  180 B, port  183 B and port  184 B are connected to each other. 
     In such a state, liquid chromatographic system  10  can perform cleaning in the third cleaning pattern targeted for first analysis flow path  291 A including high-pressure valve  180 A and cleaning in the fourth cleaning pattern targeted for second analysis flow path  291 B including high-pressure valve  180 B. 
     The rinse solution supplied from cleaning pump  143 A to high-pressure valve  180 A flows through high-pressure valve  180 A, column  230 A, and diverter valve  90 , and cleans those portions and the flow path leading to detector  500  (third cleaning pattern). 
     The rinse solution supplied from cleaning pump  143 B to high-pressure valve  180 B flows through high-pressure valve  180 B, column  230 B, and diverter valve  90 , and cleans the flow path including those portions (fourth cleaning pattern). 
     Liquid chromatographic system  10  can thus clean first analysis flow path  291 A while an operation to suction the sample continues for analysis of the sample through first analysis flow path  291 A. Furthermore, liquid chromatographic system  10  can clean second analysis flow path  291 B. Liquid chromatographic system  10  can naturally clean third analysis flow path  291 C including high-pressure valve  180 C and fourth analysis flow path  291 D including high-pressure valve  180 D together. 
     &lt;Example of Cleaning During Injection of Sample&gt; 
       FIG.  17    is a diagram showing an example in which the flow path is cleaned in the fourth cleaning pattern during injection of the sample. In particular, an example in which second analysis flow path  291 B is cleaned in the fourth cleaning pattern while the sample is injected into column  230 A in first analysis flow path  291 A will be described. 
     In  FIG.  17   , first selector valve  150  and second selector valve  160  are connected to high-pressure valve  180 A. In diverter valve  90 , port  91  leading to column  230 A and port  95  leading to detector  500  are connected to each other. 
     High-pressure pump  220 A is connected to needle  191  with high-pressure valve  180 A, first selector valve  150 , and needle valve  260  being interposed. Needle  191  is connected to injection port  198 A. The sample is held in sample loop  192 . Needle  191  injects the sample in sample loop  192  into injection port  198 A, together with the eluent supplied from high-pressure pump  220 A. The sample is thus injected into column  230 A through high-pressure valve  180 A. 
     In high-pressure valve  180 B, port  183 B and port  184 B are connected to each other. 
     In such a state, liquid chromatographic system  10  can perform cleaning in the fourth cleaning pattern targeted for second analysis flow path  291 B including high-pressure valve  180 B. Specifically, by supply of the rinse solution from cleaning pump  143 B to high-pressure valve  180 B, the flow path including high-pressure valve  180 B, column  230 B, and diverter valve  90  can be cleaned (fourth cleaning pattern). 
     Thus, liquid chromatographic system  10  can clean second analysis flow path  291 B while an operation to inject the sample into column  230 A in first analysis flow path  291 A continues. Liquid chromatographic system  10  can naturally clean third analysis flow path  291 C including high-pressure valve  180 C and fourth analysis flow path  291 D including high-pressure valve  180 D together. 
     &lt;First Example of Cleaning During Analysis of Sample&gt; 
       FIG.  18    is a diagram showing an example in which the flow path is cleaned in the second cleaning pattern during analysis of the sample. In particular, an example in which second analysis flow path  291 B is cleaned in the second cleaning pattern while the sample is being analyzed through first analysis flow path  291 A will be described. 
     In  FIG.  18   , high-pressure pump  220 A is connected to column  230 A via high-pressure valve  180 A. The sample is accommodated in column  230 A. In diverter valve  90 , port  91  leading to column  230 A and port  95  leading to detector  500  are connected to each other. The eluent supplied from high-pressure pump  220 A is injected through high-pressure valve  180 A into column  230 A where the sample is accommodated. In detector  500 , analysis of the sample proceeds. 
     First selector valve  150  and second selector valve  160  are connected to high-pressure valve  180 B. Cleaning pump  143 B is connected to needle  191  with high-pressure valve  180 B, first selector valve  150 , and needle valve  260  being interposed. Needle  191  is guided to injection port  198 B. 
     In such a state, liquid chromatographic system  10  can perform cleaning in the second cleaning pattern targeted for second analysis flow path  291 B including high-pressure valve  180 B. Specifically, by supply of the rinse solution from cleaning pump  143 B to high-pressure valve  180 B, the rinse solution flows sequentially through high-pressure valve  180 B, first selector valve  150 , needle valve  260 , sample loop  192 , needle  191 , injection port  198 B, high-pressure valve  180 B, column  230 B, and diverter valve  90 , and the flow path including those portions is cleaned (second cleaning pattern). 
     Thus, liquid chromatographic system  10  can clean second analysis flow path  291 B in the second cleaning pattern while analysis of the sample proceeds in first analysis flow path  291 A. Liquid chromatographic system  10  can naturally clean, instead of second analysis flow path  291 B, third analysis flow path  291 C including high-pressure valve  180 C or fourth analysis flow path  291 D including high-pressure valve  180 D in the second cleaning pattern. 
     Liquid chromatographic system  10  can also clean second analysis flow path  291 B in the fourth pattern while analysis of the sample proceeds in first analysis flow path  291 A. Furthermore, while analysis of the sample proceeds in first analysis flow path  291 A, liquid chromatographic system  10  can clean second analysis flow path  291 B in the second cleaning pattern and also third analysis flow path  291 C in the fourth cleaning pattern. &lt;Second Example of Cleaning During Analysis of Sample&gt; 
       FIG.  19    is a diagram showing an example in which the flow path is cleaned in the fourth cleaning pattern and the fifth cleaning pattern during analysis of the sample. In particular, an example in which second analysis flow path  291 B is cleaned in the fourth cleaning pattern and the flow path including high-pressure valve  180 A is cleaned in the fifth cleaning pattern while the sample is being analyzed through first analysis flow path  291 A will be described. 
     In  FIG.  19   , first selector valve  150  and second selector valve  160  are connected to high-pressure valve  180 A. In diverter valve  90 , port  91  leading to column  230 A and port  95  leading to detector  500  are connected to each other. The eluent supplied from high-pressure pump  220 A is injected through high-pressure valve  180 A into column  230 A where the sample is accommodated. In detector  500 , analysis of the sample proceeds. 
     In needle valve  260 , port  262  and port  263  are connected to each other. In high-pressure valve  180 B, port  183 B and port  184 B are connected to each other. In such a state, liquid chromatographic system  10  can perform cleaning in the fifth cleaning pattern targeted for the flow path including high-pressure valve  180 A and cleaning in the fourth cleaning pattern targeted for second analysis flow path  291 B including high-pressure valve  180 B. 
     The rinse solution supplied from needle cleaning pump  20  to needle valve  260  flows through needle valve  260 , sample loop  192 , needle  191 , and high-pressure valve  180 A and the flow path including those portions is cleaned (fifth cleaning pattern). 
     The rinse solution supplied from cleaning pump  143 B to high-pressure valve  180 B flows through high-pressure valve  180 B, column  230 B, and diverter valve  90  and the flow path including those portions is cleaned (fourth cleaning pattern). 
     Thus, liquid chromatographic system  10  can perform cleaning in the fifth cleaning pattern targeted for the flow path including high-pressure valve  180 A and cleaning in the fourth cleaning pattern targeted for second analysis flow path  291 B including high-pressure valve  180 B while processing for analyzing the sample through first analysis flow path  291 A continues. 
     Liquid chromatographic system  10  can naturally clean third analysis flow path  291 C including high-pressure valve  180 C and fourth analysis flow path  291 D including high-pressure valve  180 D together in the fourth cleaning pattern. 
     &lt;Types of Selectable Cleaning Patterns&gt; 
       FIG.  20    is a diagram showing a cleaning pattern that can be selected for first analysis flow path  291 A to fourth analysis flow path  291 D.  FIG.  20    shows, for each of first analysis flow path  291 A to fourth analysis flow path  291 D, types of selectable cleaning patterns in each stage of three processes that proceed with the use of first analysis flow path  291 A. 
     Various cleaning patterns described so far with reference to  FIGS.  10  to  19    are summarized. For example, while first analysis flow path  291 A is being used for analysis of the sample, types of selectable cleaning patterns for cleaning of first analysis flow path  291 A to fourth analysis flow path  291 D are as shown in  FIG.  20   . 
     The flow path cleaned in the fifth cleaning pattern is the flow path through which the cleaning solution flows toward ports  181 A to  184 A which are drain ports of high-pressure valves  180 A to  180 D.  FIG.  20    shows the fifth cleaning pattern in correspondence with first analysis flow path  291 A to fourth analysis flow path  291 D, as the cleaning pattern relating to first analysis flow path  291 A to fourth analysis flow path  291 D. 
     Stages of sample suction, sample injection, and eluent injection shown in  FIG.  20    mean a stage of suction of the sample by needle  191 , a stage of injection of the sucked sample from needle  191  via injection port  198 A and high-pressure valve  180 A into column  230 A, and a stage of injection of the eluent supplied from high-pressure pump  220 A to high-pressure valve  180 A into column  230 A, respectively. 
     While the sample is being sucked by needle  191 , first analysis flow path  291 A to fourth analysis flow path  291 D can be cleaned in the third or fourth cleaning pattern. For example, first analysis flow path  291 A can be cleaned in the third cleaning pattern and second analysis flow path  291 B to fourth analysis flow path  291 D can be cleaned in the third cleaning pattern. 
     While the sucked sample is being injected from needle  191  via injection port  198 A and high-pressure valve  180 A into column  230 A, second analysis flow path  291 B to fourth analysis flow path  291 D can be cleaned in the third or fourth cleaning pattern. For example, second analysis flow path  291 B can be cleaned in the third cleaning pattern and third analysis flow path  291 C and fourth analysis flow path  291 D can be cleaned in the fourth cleaning pattern. 
     While the eluent supplied from high-pressure pump  220 A to high-pressure valve  180 A is being injected into column  230 A, first analysis flow path  291 A can be cleaned in the fifth cleaning pattern. A portion cleaned at this time includes the needle valve, sample loop  192 , needle  191 , injection port  198 A, port  182 A of high-pressure valve  180 A, and port  181 A of high-pressure valve  180 A. 
     While the eluent supplied from high-pressure pump  220 A to high-pressure valve  180 A is being injected into column  230 A, second analysis flow path  291 B to fourth analysis flow path  291 D can be cleaned in any one of the second, fourth, and fifth cleaning patterns. For example, second analysis flow path  291 B can be cleaned in the second cleaning pattern and third analysis flow path  291 C and fourth analysis flow path  291 D can be cleaned in the fourth cleaning pattern. 
     Liquid chromatographic system  10  can thus clean first analysis flow path  291 A to fourth analysis flow path  291 D in various cleaning patterns. Liquid chromatographic system  10  accepts input of the cleaning pattern to be used for cleaning of each analysis flow path and timing of cleaning. 
     A user sets the cleaning pattern to be used for cleaning of each analysis flow path and timing of cleaning, with the use of input device  120  (see  FIG.  4   ). Contents of setting are shown on display device  125  (see  FIG.  4   ). Controller  110  (see  FIG.  4   ) sets the cleaning pattern to be used for cleaning of each analysis flow path and timing of cleaning in accordance with an instruction from the user provided to input device  120 . 
     &lt;Exemplary Setting for Cleaning Pattern&gt; 
       FIG.  21    is a timing chart showing exemplary setting for the cleaning pattern. 
     In  FIG.  21   , (1) to (5) mean the first to fifth cleaning patterns, respectively. A flow of processing performed by liquid chromatographic system  10  in accordance with the cleaning pattern and the timing of cleaning set in accordance with an instruction from the user will be described with reference to  FIG.  21   . 
     Analysis of the sample is conducted with successive use of first analysis flow path  291 A to fourth analysis flow path  291 D. Initially, first analysis flow path  291 A is cleaned in the first cleaning pattern. Thus, the flow path including high-pressure valve  180 A, first selector valve  150 , needle valve  260 , sample loop  192 , needle  191 , injection port  198 A, high-pressure valve  180 A, column  230 A, and diverter valve  90  is cleaned with the rinse solution. Furthermore, the flow path leading from diverter valve  90  to detector  500  is cleaned with the rinse solution. 
     Then, the sample is sucked by needle  191  in first analysis flow path  291 A. While the sample is sucked by needle  191 , second analysis flow path  291 B to fourth analysis flow path  291 D are cleaned in the fourth cleaning pattern. Thus, for example, in second analysis flow path  291 B, the flow path leading from high-pressure valve  180 B to column  230 B and the flow path leading from column  230 B to ports  96  and  97  of diverter valve  90  are cleaned. 
     As suction of the sample in first analysis flow path  291 A ends, processing for injecting the sample together with the eluent into column  230 A is performed. As all the sample is injected from needle  191 , cleaning in the fifth cleaning pattern is performed. The flow path including needle valve  260 , sample loop  192 , needle  191 , injection port  198 A, and high-pressure valve  180 A is thus cleaned. 
     As all the sample is injected from needle  191  in first analysis flow path  291 A, the state of connection of high-pressure valve  180 A is switched and processing for feeding the eluent to the sample injected into column  230 A is started. Analysis thus proceeds in detector  500 . 
     While analysis proceeds in first analysis flow path  291 A, cleaning in the second cleaning pattern is performed in the order of second analysis flow path  291 B to fourth analysis flow path  291 D. When analysis ends in first analysis flow path  291 A, first analysis flow path  291 A is cleaned in the second cleaning pattern and in the third cleaning pattern. 
     Then, processing for analyzing the sample through second analysis flow path  291 B is started. Specifically, an object to which first selector valve  150  and second selector valve  160  are connected is switched from high-pressure valve  180 A to high-pressure valve  180 B. In succession, second analysis flow path  291 B is cleaned in the first cleaning pattern. 
     Hereafter, as shown in  FIG.  21   , in a similar procedure, processing for analyzing the sample through second analysis flow path  291 B to fourth analysis flow path  291 D and processing for cleaning first analysis flow path  291 A to fourth analysis flow path  291 D are repeated. 
     &lt;Cleaning With Rinse Solution and Eluent as Being Combined&gt; 
       FIG.  22    is a timing chart showing an exemplary pattern of driving cleaning pumps  143 A to  143 D and high-pressure pumps  220 A to  220 D. Liquid chromatographic system  10  can use the rinse solution and the eluent (blank solution) as the cleaning solution in cleaning of the flow path in the first to fourth cleaning patterns. 
     For example, in cleaning of first analysis flow path  291 A, initially, cleaning pump  143 A is driven. The first analysis flow path is thus cleaned with the rinse solution. At a time point of lapse of time T 1  since drive of cleaning pump  143 A, high-pressure pump  220 A instead of cleaning pump  143 A is driven. The first analysis flow path is thus cleaned with the eluent. At a time point of lapse of time T 2  since drive of high-pressure pump  220 A, drive of high-pressure pump  220 A is stopped. 
     According to such a drive pattern, after cleaning with the rinse solution, the eluent flows. Therefore, the mobile phase composed of the eluent can be in equilibrium in columns  230 A to  230 D. Such a drive pattern may be adopted in all of the first to fourth cleaning patterns. For example, in setting for the cleaning pattern shown in  FIG.  21   , the rinse solution and the eluent as shown in  FIG.  22    may be combined with each other. 
     Though drive of high-pressure pump  220 A is stopped at the time point of lapse of time T 2  since drive of high-pressure pump  220 A, drive of high-pressure pump  220 A does not have to be stopped but high-pressure pump  220 A may constantly be driven except for when the rinse solution is supplied from cleaning pump  143 A. 
     &lt;Flowchart (Cleaning in Each Cleaning Pattern)&gt; 
       FIG.  23    is a flowchart showing contents of processing performed by controller  110  based on the setting shown in  FIG.  21   . 
     Initially, controller  110  sets a variable N to 1 (step S 1 ). Then, controller  110  switches an Nth analysis flow path to a first cleaning position and has the Nth analysis flow path cleaned (step S 2 ). Thus, first analysis flow path  291 A is initially cleaned in the first cleaning pattern. 
     Then, controller  110  switches the Nth analysis flow path to a suction position and the sample is sucked by needle  191  (step S 3 ). Then, controller  110  switches all analysis flow paths other than the Nth analysis flow path to a fourth cleaning position and has the all analysis flow paths cleaned (step S 4 ). Thus, for example, first analysis flow path  291 A is switched to the suction position and second analysis flow path  291 B to fourth analysis flow path  291 D are cleaned in the fourth cleaning pattern. 
     Then, controller  110  determines whether or not suction of the sample has been completed (step S 5 ). More specifically, the controller determines whether or not a prescribed time period has elapsed since processing in step S 3 . Controller  110  repeats determination in step S 5  until it determines that suction of the sample has been completed. When controller  110  determines that suction of the sample has been completed, it switches the Nth analysis flow path to an injection position and has the sample injected (step S 6 ). Thus, the sample is injected into column  230 A, for example, in first analysis flow path  291 A. 
     Then, controller  110  determines whether or not injection of the sample has been completed (step S 7 ). More specifically, the controller determines whether or not a prescribed time period has elapsed since processing in step S 6 . Controller  110  repeats determination in step S 7  until it determines that injection of the sample has been completed. When controller  110  determines that injection of the sample has been completed, it switches the Nth analysis flow path to a fifth cleaning position and has the Nth analysis flow path cleaned (step S 8 ). Thus, for example, first analysis flow path  291 A is cleaned in the fifth cleaning pattern. Furthermore, controller  110  switches analysis flow paths other than the Nth analysis flow path successively to a second cleaning position and has other analysis flow paths cleaned (step S 9 ). Thus, for example, second analysis flow path  291 B to fourth analysis flow path  291 D are successively cleaned in the third cleaning pattern. 
     Then, controller  110  determines whether or not predetermined analysis time has elapsed (step S 10 ). Controller  110  repeats determination in step S 10  until it determines that the analysis time has elapsed. When the analysis time has elapsed, controller  110  successively switches the Nth analysis flow path to the second cleaning position and a third cleaning position and has the Nth analysis flow path cleaned (steps S 11  and S 12 ). Thus, for example, first analysis flow path  291 A is cleaned successively in the second cleaning pattern and the third cleaning pattern. 
     Then, controller  110  determines whether or not all analysis methods in a method file have been completed (step S 13 ). A schedule for analysis of the sample through the first to fourth analysis flow paths is stored as a method file in controller  110 . The method file includes also the cleaning pattern and the timing of cleaning. 
     When controller  110  determines that all the analysis methods in the method file have not been completed, it updates variable N (step S 14 ). Thus, for example, the analysis flow path to be used for analysis of the sample is updated from first flow path  291 A to second analysis flow path  291 B. Thereafter, the controller has the process return to processing in step S 2 . When controller  110  determines that all the analysis methods in the method file have been completed, it quits the process based on the present flowchart. 
     &lt;Flowchart (Setting for Cleaning Pattern)&gt; 
       FIG.  24    is a flowchart showing contents of processing relating to setting for the cleaning pattern. Processing based on the present flowchart is performed by controller  110 . 
     Initially, controller  110  determines whether or not it detects an operation for setting (step S 21 ). For example, controller  110  determines whether or not it detects an operation for making setting through input device  120 . When the controller does not detect an operation for setting, the process based on the present flowchart ends. 
     When controller  110  detects the operation for setting, it reads a setting item from memory  112  (step S 22 ). The setting item includes a sample analysis schedule and the cleaning pattern for each of first analysis flow path  291 A to fourth analysis flow path  291 D. Then, controller  110  has the read setting item displayed on a screen of display device  125  (step S 23 ). 
     Then, controller  110  updates setting for the setting item in accordance with an operation by the user (step S 24 ). Contents set in accordance with the operation by the user include also the cleaning pattern and a condition for cleaning in that cleaning pattern. The condition for cleaning includes a time period for cleaning, the number of times of cleaning, and a type of the cleaning solution. Through processing in step S 24 , the sample analysis schedule and the cleaning pattern are updated for each of first analysis flow path  291 A to fourth analysis flow path  291 D. Consequently, a method file for new analysis is generated. 
     Then, controller  110  determines whether or not it detects completion of the operation by the user (step S 25 ). When controller  110  does not detect completion of the operation by the user, the process returns to step S 23 . When controller  110  detects completion of the operation by the user, it updates setting in memory  112  to contents in step S 24  (step S 26 ) and quits the process based on the present flowchart. 
     &lt;Setting Screen&gt; 
       FIG.  25    is a diagram showing an exemplary setting screen for automatic cleaning. Controller  110  has a setting item shown on the screen of display device  125  (see  FIG.  4   ) when it accepts an operation for changing setting for automatic cleaning of the flow path. Consequently, a setting screen for automatic cleaning of the flow path including first analysis flow path  291 A to fourth analysis flow path  291  is shown on display device  125  (see  FIG.  4   ). 
       FIG.  25    exemplifies a setting screen  400 . The user can set an analysis flow path (stream) to be cleaned, the cleaning pattern, and the type of the cleaning solution while the user looks at setting screen  400 . For example, when the user operates any one of a plurality of setting items with a mouse or the like, a window for the setting item corresponding to the operation opens in setting screen  400 . The user can input a desired setting value in the opened window. For example, in setting screen  400 , a window  404  that opens in response to an operation to select a target setting item  401  is shown. 
     For example, the user can select a sample to be cleaned in target setting item  401 , and can set a threshold value to be used for determination by controller  110  as to whether or not to clean the flow path and a threshold value for quitting cleaning. Furthermore, the user can select a method of cleaning an autosampler and a stream in an autosampler item  402  and a stream item  403 . In setting screen  400 , the user can also further set the number of times of injection of the blank solution. 
     Thus, in the present embodiment, various types of setting relating to automatic cleaning can be inputted in one setting screen so that convenience of the user is improved. 
     &lt;Modification (Cleaning in Accordance with Status of Occurrence of Carryover)&gt; 
       FIG.  26    is a flowchart showing contents of processing for cleaning the analysis flow path in accordance with a status of occurrence of carryover. Liquid chromatographic system  10  that cleans first analysis flow path  291 A to fourth analysis flow path  291 D based on a predetermined schedule has been described so far. Liquid chromatographic system  10 , however, may detect occurrence of carryover and clean first analysis flow path  291 A to fourth analysis flow path  291 D in accordance with a status of occurrence thereof. In a modification, liquid chromatographic system  10  that cleans the analysis flow path in accordance with a status of occurrence of carryover will be described. 
       FIG.  26    is a flowchart for illustrating the modification. Processing based on the present flowchart is performed by controller  110 . 
     Initially, controller  110  sets variable N to 1 (step S 31 ). Then, controller  110  obtains MS data of the Nth analysis flow path (step S 32 ). The MS data is used for determining whether or not carryover has occurred in the Nth analysis flow path. 
     For example, before start of new analysis through first analysis flow path  291 A, detector  500  obtains analysis data based on the eluent that flows in column  230 A in first analysis flow path  291 A. If some of the sample used in preceding analyses remains in first analysis flow path  291 A, the remaining sample will affect analysis data. Detector  500  transmits the obtained analysis data to controller  110  as MS data. 
     Controller  110  determines whether or not a degree of contamination of the Nth analysis flow path exceeds a threshold value, that is, whether or not carryover has occurred, based on the MS data (step S 33 ). 
     When carryover has not occurred, controller  110  switches the Nth analysis flow path to the suction position and has the sample sucked by needle  191  (step S 34 ). Then, controller  110  determines whether or not suction of the sample has been completed (step S 35 ). More specifically, the controller determines whether or not a prescribed time period has elapsed since step S 34 . Controller  110  repeats determination in step S 35  until it determines that suction of the sample has been completed. When controller  110  determines that suction of the sample has been completed, it switches the Nth analysis flow path to the injection position and has the sample injected (step S 36 ). Thus, for example, in first analysis flow path  291 A, the sample is injected into column  230 A. 
     Then, controller  110  determines whether or not injection of the sample has been completed (step S 37 ). More specifically, the controller determines whether or not a prescribed time period has elapsed since step S 36 . Controller  110  repeats determination in step S 37  until it determines that injection of the sample has been completed. When controller  110  determines that injection of the sample has been completed, it determines whether or not predetermined analysis time has elapsed (step S 38 ). Controller  110  repeats determination in step S 38  until it determines that the analysis time has elapsed. 
     Then, controller  110  determines whether or not all analysis methods in a method file have been completed (step S 40 ). When controller  110  determines that all the analysis methods in the method file have not been completed, it updates variable N (step S 41 ) and the process returns to processing in step S 32 . 
     Thus, in the modification, when controller  110  determines that carryover has not occurred, it proceeds with processing for analysis through the analysis flow path of interest, without having cleaning in any of cleaning patterns  1  to  5  being performed. 
     When controller  110  determines in step S 33  that carryover has occurred, it proceeds with processing for analysis through the Nth analysis flow path while it has the analysis flow path cleaned in accordance with the cleaning pattern and the timing of cleaning set in advance, in conformity with setting (step S 39 ). Consequently, for example, depending on setting, processing shown in  FIG.  23    may be performed. Thereafter, when controller  110  determines that all the analysis methods in the method file have been completed (YES in step S 40 ), the controller quits the process based on the present flowchart. 
     According to the present modification, since the analysis flow path is cleaned in accordance with the status of occurrence of carryover, essentially unnecessary cleaning can be prevented from being performed. Depending on the degree of contamination on the occurrence of carryover, the cleaning pattern to be used for cleaning may be changed. 
     &lt;Other Modifications&gt; 
     (1) While the analysis flow path inclusive of diverter valve  90  is being cleaned, a portion to be cleaned in diverter valve  90  may be switched between port  95  connected to detector  500  and ports  96  and  97  connected to the liquid discharge pipe. In other words, as shown in  FIG.  21   , the analysis flow path may be cleaned in the second cleaning pattern and thereafter cleaned in the third cleaning pattern. Such switching of the cleaning pattern may be made based on a predetermined schedule. Alternatively, such switching of the cleaning pattern may be made in accordance with the status of occurrence of carryover. 
     (2) The number of high-pressure valves included in liquid chromatographic system  10  is not limited to four. For example, two high-pressure valves or five or more high-pressure valves may be provided. With increase in number of high-pressure valves, the number of analysis flow paths that can be used for analysis of a sample can be increased. 
     (3) Needle cleaning pump  20  does not have to be provided. Needle valve  260  does not have to be provided. In this case, a pipe that extends from sample loop  192  may be connected to first selector valve  150 . 
     (4) A control unit that controls sample injection device  100  may be provided separately from controller  110  that controls liquid chromatographic system  10 . In this case, controller  110  may control liquid chromatographic system  10  including sample injection device  100  in coordination with the control unit. 
     (5) A stationary phase with which columns  230 A to  230 D are filled should only be a stationary phase that can be used as the stationary phase for analysis in the liquid chromatographic system, and the same stationary phase or different stationary phases may be employed. The eluent with which containers  210 A to  210 D are filled should only be a solution that can be used as the mobile phase for analysis in the liquid chromatographic system, and the same solution or different solutions may be employed. 
     (6) A setting screen for setting a cleaning pattern for each of first analysis flow path  291 A to fourth analysis flow path  291 D may be shown on display device  125 . In that case, an item with which setting for the cleaning pattern can be made for each of first analysis flow path  291 A to fourth analysis flow path  291 D may be shown on a single screen of display device  125 . 
     (7) Types of the cleaning method such as the cleaning pattern and the cleaning solution and a condition for cleaning may be set by a manager through the setting screen based on a compound targeted for cleaning. 
     (8) Detector  500  is, for example, a mass spectrometer. Detector  500  may be any one of an absorbency detector, a PDA detector, a fluorescence detector, a differential refractometer, a conductivity detector, an evaporative light scattering detector, an electrochemical detector, an infrared spectrophotometer, an optical rotation detector, a circular dichroism detector, a flame ionization detector, a radiation detector, a dielectric constant detector, a chemiluminescence detector, an atomic absorption spectrophotometer, an inductive coupling plasma optical emission spectrometer, a high-frequency plasma mass spectrometer, a heat detector, an optical scattering detector, a viscosity detector, an ion electrode, an ultrasonic detector, and a nuclear magnetic resonance apparatus. 
     [Aspects] 
     Illustrative embodiments described above are understood by a person skilled in the art as specific examples of aspects below. 
     (Clause 1) A method according to one aspect is a method of cleaning a liquid chromatographic system. The liquid chromatographic system includes a first column and a second column for separation of a sample, a needle that takes a sample to be injected into the first column and the second column, an injection valve portion to which the first column and the second column are connected, the injection valve portion including a first injection valve connected to the first column and a second injection valve connected to the second column, a first pump that supplies an eluent to the first injection valve, a second pump that supplies an eluent to the second injection valve, a first analysis flow path constructed such that the eluent flows from the first injection valve toward the first column, a second analysis flow path constructed such that the eluent flows from the second injection valve toward the second column, and a selector valve connected to the first column and the second column, the selector valve switching an object to be connected to a detector between the first analysis flow path and the second analysis flow path. The method of cleaning a liquid chromatographic system includes setting a condition for feeding a cleaning solution or a blank sample to the selector valve, cleaning the first analysis flow path by feeding the cleaning solution or the blank sample while a first flow path through which the eluent flows from the first injection valve to the first column via the needle is set, and cleaning the first analysis flow path by feeding the cleaning solution or the blank sample while a second flow path through which the eluent flows from the first injection valve to the first column not via the needle is set. 
     According to the method of cleaning a liquid chromatographic system described in Clause 1, occurrence of carryover can be lessened, or on the occurrence of carryover, the carryover can be eliminated. 
     (Clause 2) A liquid chromatographic system according to another aspect includes a first column and a second column for separation of a sample, a needle that takes a sample to be injected into the first column and the second column, an injection valve portion to which the first column and the second column are connected, the injection valve portion including a first injection valve connected to the first column and a second injection valve connected to the second column, a first pump that supplies an eluent to the first injection valve, a second pump that supplies an eluent to the second injection valve, a first analysis flow path constructed such that the eluent flows from the first injection valve toward the first column, a second analysis flow path constructed such that the eluent flows from the second injection valve toward the second column, a selector valve connected to the first column and the second column, the selector valve switching an object to be connected to a detector between the first analysis flow path and the second analysis flow path, and a controller. The controller can have the first analysis flow path cleaned by feed of a cleaning solution or a blank sample while a first flow path through which the eluent flows from the first injection valve to the first column via the needle is set, and can have the first analysis flow path cleaned by feed of the cleaning solution or the blank sample while a second flow path through which the eluent flows from the first injection valve to the first column not via the needle is set. 
     According to the liquid chromatographic system described in Clause 2, occurrence of carryover can be lessened, or on the occurrence of carryover, the carryover can be eliminated. 
     (Clause 3) In the liquid chromatographic system described in Clause 2, the selector valve includes a main port to which the detector is connected, a first port to which the first column is connected, and a second port to which the second column is connected, the selector valve is constructed to switch an object to be connected to the main port between the first port and the second port, and the controller can have first cleaning performed to clean the first analysis flow path while the first flow path is set and while the main port and the first port are connected to each other and second cleaning performed to clean the first analysis flow path while the first flow path is set and while the main port and the first port are disconnected from each other. 
     According to the liquid chromatographic system described in Clause 3, while the analysis flow path is set to the first flow path, cleaning in a state that the main port and the first port among the ports of the selector valve are connected to each other and cleaning in a state that the main port and the first port are disconnected from each other can be performed. Therefore, the first flow path can minutely be cleaned. 
     (Clause 4) In the liquid chromatographic system described in Clause 3, the controller can have third cleaning performed to clean the first analysis flow path while the second flow path is set as the first analysis flow path by means of the first injection valve and while the main port and the first port are connected to each other and fourth cleaning performed to clean the first analysis flow path while the second flow path is set as the first analysis flow path by means of the first injection valve and while the main port and the first port are disconnected from each other. 
     According to the liquid chromatographic system described in Clause 4, while the analysis flow path is set to the second flow path, cleaning in a state that the main port and the first port among the ports of the selector valve are connected to each other and cleaning in a state that the main port and the first port are disconnected from each other can be performed. Therefore, the second flow path can minutely be cleaned. 
     (Clause 5) In the liquid chromatographic system described in any one of Clauses 2 to 4, the controller has the third cleaning performed following the second cleaning. 
     According to the liquid chromatographic system described in Clause 5, by performing third cleaning in succession to second cleaning, the analysis flow path can further minutely be cleaned. 
     (Clause 6) In the liquid chromatographic system described in any one of Clauses 2 to 5, the controller can have the selector valve cleaned by feed of the blank sample to the first injection valve or the second injection valve. 
     According to the liquid chromatographic system described in Clause 6, owing to the blank sample, in the selector valve, occurrence of carryover can be lessened, or on the occurrence of carryover, the carryover can be eliminated. 
     (Clause 7) The liquid chromatographic system described in any one of Clauses 2 to 6 further includes a first cleaning pump that supplies the cleaning solution to the first injection valve and a second cleaning pump that supplies the cleaning solution to the second injection valve. In the liquid chromatographic system, the controller can have the selector valve cleaned with the cleaning solution that flows through the first analysis flow path and the cleaning solution that flows through the second analysis flow path by having the first cleaning pump and the second cleaning pump driven. 
     According to the liquid chromatographic system described in Clause 7, the flow path including the selector valve through the first analysis flow path and the flow path including the selector valve through the second analysis flow path can efficiently be cleaned. 
     (Clause 8) In the liquid chromatographic system described in any one of Clauses 2 to 7, the controller specifies a degree of contamination of the eluent that flows from the first column to the detector based on analysis data outputted from the detector, and when the degree of contamination exceeds a threshold value, the controller has the first analysis flow path cleaned in a pattern set in advance. 
     According to the liquid chromatographic system described in Clause 8, efficient cleaning in accordance with a degree of contamination of the first analysis flow path can be performed. 
     (Clause 9) The liquid chromatographic system described in any one of Clauses 2 to 8 further includes a needle valve and a needle cleaning pump connected to the needle valve, the needle cleaning pump supplying the cleaning solution. The needle includes a tip end and a base end. The tip end is connected to the injection valve portion via an injection port and the base end is connected to the needle valve through a pipe. The injection valve portion includes a needle port to which the injection port is connected and a drain port to which a discharge flow path is connected. The controller can have the needle cleaned by drive of the needle cleaning pump while the needle port and a discharge port are connected to each other by means of the injection valve portion. 
     According to the liquid chromatographic system described in Clause 9, a needle portion can be cleaned. 
     (Clause 10) The liquid chromatographic system described in any one of Clauses 2 to 9 further includes a memory in which setting relating to cleaning of the first flow path and the second flow path is stored. The controller updates the setting stored in the memory based on an operation for changing the setting and has the first flow path or the second flow path cleaned based on the setting stored in the memory. 
     According to the liquid chromatographic system described in Clause 10, by variously changing setting for cleaning depending on a status, the first flow path or the second flow path can appropriately be cleaned. 
     (Clause 11) The liquid chromatographic system described in Clause 10 further includes a display device. When the controller accepts the operation for changing the setting, the controller has an item of the setting shown on a screen of the display device. 
     According to the liquid chromatographic system described in Clause 11, the item of setting is shown on the screen of the display device. Therefore, setting can readily be changed. 
     (Clause 12) In the liquid chromatographic system described in any one of claims 2 to 11, the controller can have the second analysis flow path cleaned when a flow path through which the eluent flows from the second injection valve to the second column via the needle or a flow path through which the eluent flows from the second injection valve to the second column not via the needle is set as the second analysis flow path by means of the second injection valve. 
     According to the liquid chromatographic system described in Clause 12, the second analysis flow path in addition to the first analysis flow path can also appropriately be cleaned. 
     (Clause 13) The liquid chromatographic system described in any one of Clauses 2 to 12 further includes a third column, a third injection valve connected to the third column, and a third pump that supplies the eluent to the third injection valve. The selector valve is further connected to the third column and switches the object to be connected to the detector among the first column, the second column, and the third column. 
     According to the liquid chromatographic system described in Clause  13 , with the use of the third analysis flow path in addition to the first and second analysis flow paths, the sample can more efficiently be analyzed. 
     Though an embodiment of the present invention has been described, it should be understood that the embodiment disclosed herein is illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.