Pretreatment device and pretreatment method

Abstract

This pretreatment device (2) suctions liquid components as a pretreatment from a culture sample separated into liquid components and solid components across a solid-liquid interface within a container (14). The pretreatment device (2) comprises suction tubes (58, 59) for suctioning the liquid components, a pump (54) for imparting negative pressure to the suction tubes, and a control unit (500) for moving the negatively-pressured suction tubes in the direction of the solid-liquid interface within the liquid components.

Description

[Technical Field]

[0001] The present disclosure relates to a pretreatment device and a pretreatment method. [Background technology]

[0002] A technique for performing analyses such as metabolome analysis by supplying cells of microorganisms, plants, or the like to a liquid chromatograph mass spectrometer is known. The cells supplied to the liquid chromatograph mass spectrometer or the like are cultured in a culture medium in a culture tank. This type of technique uses a sampling device for sampling the culture medium containing the cells and a pretreatment device for pretreatment of the cells contained in the sampled culture medium.

[0003] In the pretreatment device, a centrifuge mechanism is applied to a container containing a culture medium. As a result, the culture product, such as cells, accumulates as a solid at the bottom of the container, and the solid component (the culture product) and the liquid component (the supernatant) are separated by a solid-liquid interface. By sucking the liquid component from the container using a suction tube inserted into the container, the solid component and the liquid component can be separated and recovered separately.

[0004] In order to prevent any liquid components from remaining in the container, it is possible to aspirate the liquid components while keeping the aspirator close to the solid-liquid interface. In this case, it is important to accurately detect the solid-liquid interface.

[0005] Patent Document 1 describes a technique for capturing an image of a solid-liquid interface in a state where light is uniformly applied to a container from the outside using area illumination, in order to accurately detect the position of the solid-liquid interface. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2020 / 017411 Summary of the Invention [Problem to be solved by the invention]

[0007] The closer the position of the suction tube that sucks the liquid component is to the solid-liquid interface, the less liquid component remains in the container. However, when the liquid component is sucked up with the suction tube, a liquid flow occurs. This liquid flow causes the settled solid component to be lifted up, and there is a risk that the solid component will be sucked up by the suction tube along with the liquid component. The effect of the liquid flow becomes greater the closer the position of the suction tube that sucks up the liquid component is to the solid-liquid interface.

[0008] An object of the present disclosure is to increase the amount of liquid components that can be aspirated from a culture sample while minimizing the inclusion of solid components in the aspirate. [Means for solving the problem]

[0009] The pretreatment device disclosed herein aspirates a liquid component from a culture sample separated into a liquid component and a solid component across a solid-liquid interface in a container as a pretreatment. The pretreatment device includes an aspirating tube for aspirating the liquid component, a pump for applying negative pressure to the aspirating tube, and a control unit for moving the aspirating tube under negative pressure toward the solid-liquid interface within the liquid component.

[0010] The pretreatment method disclosed herein is a pretreatment method in which a liquid component is aspirated using an aspirator tube from a culture sample that has been separated into a liquid component and a solid component separated by a solid-liquid interface within a container, and includes the steps of applying negative pressure to the aspirator tube and moving the aspirator tube with the negative pressure applied in the direction of the solid-liquid interface within the liquid component. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to increase the amount of liquid components that can be aspirated from a culture sample while minimizing the inclusion of solid components in the aspirate. [Brief explanation of the drawings]

[0012] [Figure 1]FIG. 1 is a block diagram showing a schematic configuration of an automatic pretreatment system. [Figure 2] FIG. 2 is a diagram showing a schematic configuration of a liquid removal mechanism. [Figure 3] FIG. 10 shows a procedure for aspirating the supernatant. [Figure 4] 10 is a timing chart showing the control of aspirating the supernatant. [Figure 5] 10 is a flowchart showing the control of aspirating the supernatant (first embodiment). [Figure 6] 10 is a flowchart showing the control of aspirating the supernatant (Embodiment 2). DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0014] Embodiment 1 <Outline of the automatic pre-processing system> 1 is a block diagram showing a schematic configuration of an automatic pretreatment system 10. The automatic pretreatment system 10 is an apparatus for automatically performing pretreatment on an object to be analyzed. In this embodiment, the object to be analyzed is, for example, cultured cells, more specifically, bacterial cells.

[0015] The automatic pretreatment system 10 includes a sampling device 1 and a pretreatment device 2. Metabolites of the cells are extracted from the cells after pretreatment by the automatic pretreatment system 10. The extracted metabolites are supplied to a liquid chromatograph mass spectrometer 3. The liquid chromatograph mass spectrometer 3 is merely one example of an analytical device for analyzing an analyte. It is also possible to analyze an analyte using other analytical devices.

[0016] The sampling device 1 is a device for sampling a liquid from a container (culture container). For example, microorganisms or plant cells are cultured in a culture solution in a container called a bioreactor. The bioreactor is equipped with, for example, a stirring member that is rotated using magnetic force, an oxygen concentration sensor for detecting the concentration of dissolved oxygen, and the like. Cells are cultured in the sampling device 1 by adjusting the dissolved oxygen concentration while stirring the culture solution in the bioreactor.

[0017] The pretreatment device 2 pretreats cells contained in a culture solution (culture sample) sampled from inside a bioreactor. In the sampling device 1, the culture solution containing cells is contained in a test tube serving as a container (sampling container). The pretreatment device 2 includes a centrifugation mechanism 4, a liquid removal mechanism 5, a reagent supply mechanism 6, a stirring mechanism 7, and an extraction mechanism 8. Each of these mechanisms sequentially pretreats the cells contained in the culture solution in the test tube.

[0018] The centrifugal separator 4 applies centrifugal force to the culture solution in the test tube. This separates the culture solution in the test tube at the solid-liquid interface into a solid component that sinks to the bottom of the test tube and a liquid component that floats on top of the solid component. The solid component is the culture product, for example, cultured cells. The liquid component that floats on top of the solid component is the supernatant separated from the culture solution.

[0019] The liquid removal mechanism 5 aspirates the supernatant from the test tube. This removes the liquid from the test tube, leaving the cells in the test tube. The reagent supply mechanism 6 supplies a reagent for extracting metabolic products in the cells to the cells in the test tube. This creates a mixture of cells and reagent in the test tube. The stirring mechanism 7 stirs the mixture. By stirring the mixture, a suspension is obtained in which metabolic products have been extracted from the cells.

[0020] The extraction mechanism 8 extracts a part of the suspension as an extract, which is supplied to the liquid chromatograph mass spectrometer 3. <Schematic configuration of liquid removal mechanism 5> FIG. 2 is a diagram showing a schematic configuration of the liquid removing mechanism 5. As shown in FIG.

[0021] The liquid removal mechanism 5 includes a mounting plate 50 to which various members are attached, and a control unit 500. A holding mechanism 51, a driving mechanism 52, a moving mechanism 53, a pump 54, a housing 55, a camera 56, and a surface light 57 are attached to the mounting plate 50.

[0022] The holding mechanism 51 includes a pair of displacement parts 511 for holding the test tube 14. The pair of displacement parts 511 are arranged to face each other in the horizontal direction.

[0023] A nozzle 58 is connected to the pump 54. A tip 59 is attached to the tip of the nozzle 58. When the pump 54 applies negative pressure to the nozzle 58, a suction force is generated at the tip of the tip 59. The liquid sucked by the tip 59 passes through a discharge pipe (not shown) and is collected. The drive mechanism 52 moves the nozzle 58 vertically together with the pump 54.

[0024] Housing 55 is formed to be hollow. Test tube 14 is placed inside housing 55. An opening 551 for inserting test tube 14 is formed in the top surface of housing 55. An opening 552 for inserting shaft 531 of moving mechanism 53 is formed in the bottom surface of housing 26. Planar light 57 is placed inside housing 55. The lens portion of camera 56 is placed inside housing 55 at a position facing planar light 57 with test tube 14 in between.

[0025] The moving mechanism 53 includes a shaft 531 and a base 532 provided at the tip of the shaft 531. A recess 533 is formed in the base 532. The bottom of the test tube 14 is placed in the recess 533. The moving mechanism 53 can adjust the position of the base 532 by sliding the shaft 531 in the axial direction.

[0026] The control unit 500 includes a processor 501 and a memory 502. The processor 501 is typically an arithmetic processing unit such as a CPU (Central Processing Unit) or an MPU (Multi-Processing Unit). The processor 501 reads and executes programs stored in the memory 502 to realize various processes of the liquid removal mechanism 5. Note that while FIG. 2 illustrates an example of a configuration in which the control unit 500 has a single processor 501, the control unit 500 may also be configured to have multiple processors 501.

[0027] The memory 502 is realized by a non-volatile memory such as a random access memory (RAM), a read only memory (ROM), or a flash memory. The memory 502 stores various data such as the programs executed by the processor 501, as well as the control times of the drive mechanism 52 and the pump 54.

[0028] In addition, memory 502 may be a CD-ROM (Compact Disc - Read Only Memory), a DVD-ROM (Digital Versatile Disk - Read Only Memory), a USB (Universal Serial Bus) memory, a memory card, a FD (Flexible Disk), a hard disk, an SSD (Solid State Drive), a magnetic tape, a cassette tape, an MO (Magnetic Optical Disc), an MD (Mini Disc), an IC (Integrated Circuit) card (excluding memory cards), an optical card, a mask ROM, or an EPROM, as long as it can non-temporarily record a program in a format readable by processor 101.

[0029] The control unit 500 sends control signals to the drive mechanism 52, the pump 54, and the camera 56. The drive mechanism 52 moves the nozzle 58 vertically based on the control signal. This causes the nozzle 58 to be inserted into the test tube 14. The drive mechanism 52 also controls the position of a tip 59 attached to the tip of the nozzle 58. The pump 54 applies negative pressure to the nozzle 58 based on the control signal. This generates a suction force in the nozzle 58. The camera 56 takes an image based on the control signal and sends the image to the control unit 500. This allows the control unit 500 to obtain an image including the solid-liquid interface of the culture sample in the test tube 14. <Procedure for liquid removal mechanism 5 to aspirate supernatant> 3 is a diagram showing the procedure for aspirating the supernatant. For example, the liquid removal mechanism 5 aspirates the supernatant in the test tube 14 in the procedure described below. In the test tube 14, the supernatant and the bacteria are present in a separated state, separated by a solid-liquid interface.

[0030] First, a tip 59 is inserted into the supernatant from above the test tube 14 (FIG. 3(1)). The tip 59 is attached to the tip of a nozzle 58 (see FIG. 2).

[0031] Next, the tip of the tip 59 is moved to a position in the supernatant that is a distance H away from the solid-liquid interface toward the liquid surface (Figure 3(2)). Next, suction of the supernatant begins at that position. As a result, the supernatant is gradually suctioned from the tip of the tip 59, and the liquid surface descends. Eventually, the liquid surface approaches the tip of the tip 59 (Figure 3(3)).

[0032] The distance H can be set between the liquid surface and the solid-liquid interface. The greater the distance H, the closer the tip of the tip 59 is to the liquid surface. Aspirating the supernatant with the tip of the tip 59 held close to the liquid surface can prevent many bacteria from being lifted up due to the influence of the supernatant (liquid) flow caused by suction, compared to aspirating the supernatant with the tip of the tip 59 held close to the solid-liquid interface. On the other hand, when aspirating the supernatant with the tip of the tip 59 held close to the liquid surface, the amount of supernatant that can be aspirated at that position is reduced. Therefore, the distance H can be designed taking into consideration the influence of the supernatant flow caused by suction and the amount of supernatant aspirated.

[0033] After the liquid surface approaches the tip of tip 59, tip 59 is lowered slowly toward the solid-liquid interface while maintaining the state of aspirating the supernatant (FIG. 3(4)). As a result, the supernatant present in the area occupying the distance H from the solid-liquid interface is gradually aspirated by tip 59.

[0034] As the tip of tip 59 approaches the solid-liquid interface, the extent to which the supernatant flow caused by suction affects the bacteria becomes greater. However, because tip 59 is moved at a low speed while suction is continued, this effect can be minimized.

[0035] When the tip of the tip 59 eventually reaches the solid-liquid interface, the tip 59 is stopped from descending. With the tip of the tip 59 at the solid-liquid interface, the tip 59 continues to suck up the supernatant (FIG. 3(5)). As a result, the supernatant present near the solid-liquid interface is sucked up by the tip 59.

[0036] As in the past, when the tip of tip 59 is lowered to the solid-liquid interface in the presence of a large amount of supernatant and then the suction of the supernatant is started, there is a possibility that the bacterial cells will fly up due to the influence of the supernatant flow caused by the suction. However, in this embodiment, the supernatant is aspirated while the tip of tip 59 is being lowered to the solid-liquid interface, so that the amount of supernatant remaining in test tube 14 when the tip of tip 59 reaches the solid-liquid interface is small. For example, if tip 59 is moved in conjunction with the position of the descending liquid surface by aspirating the supernatant, the amount of supernatant remaining in test tube 14 when tip 59 reaches the solid-liquid interface will be extremely small.

[0037] Therefore, the suction time required at the solid-liquid interface can be minimized, which reduces the possibility of aspirating the bacterial cells together with the supernatant.

[0038] Moreover, in this embodiment, the suction of the supernatant does not begin when the tip of the tip 59 reaches the solid-liquid interface, but rather continues from before that. Therefore, a flow of the supernatant does not occur suddenly when the tip of the tip 59 reaches the solid-liquid interface. Moreover, the amount of supernatant that forms the flow is small. Therefore, the possibility of the bacterial cells being stirred up by the influence of the supernatant flow can be reduced. As a result, the possibility of the bacterial cells being sucked in along with the supernatant is reduced.

[0039] When all the supernatant has been aspirated, the tip 59 is pulled up (FIG. 3(6)). This completes the entire procedure for aspirating the supernatant. <Timing chart showing the control of supernatant aspiration> 4 is a timing chart showing the control of the supernatant aspirating process, in which the procedure described with reference to FIG.

[0040] In Fig. 4, the vertical axis represents the vertical position within the test tube 14. The horizontal axis in Fig. 4 represents the time axis. Below the time axis in Fig. 4, the timings at which the pump 54 is turned on and off and the timings at which images of the test tube 14 are taken by the camera 56 are shown.

[0041] In the test tube 14 shown in Figure 4, the bacterial cells and the supernatant are present in a separated state. The vertical axis indicates the position of the solid-liquid interface between the bacterial cells and the supernatant and the liquid level of the supernatant. (1) to (5) in Figure 4 correspond to (1) to (5) in Figure 3.

[0042] In the figure, Tp indicates the position of the tip of the tip 59. Ls indicates the position of the liquid surface that changes as the supernatant is sucked.

[0043] Initially, the tip of the tip 59 is in an initial position. At this time, the liquid removal mechanism 5 captures an image A near the solid-liquid interface with the camera 56. Because the tip position Tp of the tip 59 is away from the solid-liquid interface, the tip of the tip 59 is not included in the image A.

[0044] Next, the liquid removal mechanism 5 moves the tip of the tip 59 from the initial position to the immersion position. The immersion position is set to a position lower than the liquid surface of the supernatant. The immersion position is also set to a position where the tip of the tip 59 will appear in the captured image when the position of the solid-liquid interface is photographed at the same photographing position as image A. With the tip of the tip 59 in the immersion position, the liquid removal mechanism 5 uses the camera 56 to photograph image B near the solid-liquid interface.

[0045] The liquid removal mechanism 5 uses images A and B to detect the solid-liquid interface and the tip of the tip 59. For example, the liquid removal mechanism 5 accurately detects the tip of the tip 59 based on the image difference between images A and B. That is, by calculating the difference in brightness between each pixel of image A, which does not include the tip of the tip 59, and each pixel of image B, which includes the tip of the tip 59, a large brightness difference is calculated only in the tip of the tip 59. Therefore, the liquid removal mechanism 5 can accurately detect the tip of the tip 59 based on the calculation result.

[0046] Next, the liquid removal mechanism 5 moves the tip of the tip 59 from the immersion position to the reference position. The reference position is a distance H away from the solid-liquid interface toward the liquid surface. The liquid removal mechanism 5 does not turn on the pump 54 at the immersion position. Furthermore, the liquid removal mechanism 5 does not turn on the pump 54 while moving the tip of the tip 59 from the immersion position to the reference position. However, the pump 54 may be turned on at these times.

[0047] Next, the liquid removal mechanism 5 keeps the tip of the tip 59 at the reference position and turns on the pump 54. This causes the supernatant to be aspirated from the tip of the tip 59. The liquid level Ls descends over time. When time T1 has elapsed since the pump 54 was turned on, the liquid removal mechanism 5 lowers the tip 59 at a low speed.

[0048] When time T1 has elapsed since the pump 54 was turned on, the liquid level Ls approaches the reference position. Time T1 may be set so that the tip 59 descends after the liquid level Ls reaches the reference position. In other words, time T1 may be set to coincide with the timing after the tip 59 has finished aspirating all of the supernatant present above the reference position. Setting time T1 in this manner allows more supernatant to be aspirated at the reference position, which is far from the solid-liquid interface. The control unit 500 may detect a change in pressure at the tip of the tip 59 to determine whether the tip of the tip 59 is located within the supernatant or in contact with the liquid surface.

[0049] The liquid removal mechanism 5 slowly lowers the tip of the tip 59 from the reference position to the solid-liquid interface over a period of time T2. During this time, the liquid removal mechanism 5 keeps the pump 54 turned on. As a result, the supernatant is gradually sucked into the tip 59, and the liquid level Ls drops. Figure 4 shows an example in which the tip position Tp of the tip 59 is lowered so that it is positioned slightly below the liquid level Ls.

[0050] By keeping the tip of the tip 59 lowered at a position close to the liquid level Ls, the supernatant can be aspirated at a position always far from the solid-liquid interface, which prevents the bacterial cells from being lifted up due to the influence of the supernatant flow caused by the aspirate.

[0051] 4 is merely an example. The descending speed of the tip 59 may be controlled to be sufficiently slow so that the tip position Tp of the tip 59 descends along the liquid level Ls.

[0052] In particular, if the descending speed of the tip 59 is set sufficiently slow, the speed at which the liquid level Ls drops due to the suction of the supernatant becomes faster than the speed at which the tip position Tp of the tip 59 drops. If the suction of the supernatant continues in this state, the position of the liquid level Ls will eventually catch up with the tip position Tp of the tip 59. After that, suction continues with the liquid level Ls and the tip position Tp of the tip 59 overlapping. As a result, the tip 59 descends at a slow speed while always aspirating the supernatant at the liquid level Ls, which is farthest from the solid-liquid interface. This further prevents the bacterial cells from being lifted up due to the influence of the supernatant flow caused by suction.

[0053] According to this embodiment, it is possible to continue aspirating the supernatant at the liquid level Ls that is always the farthest from the solid-liquid interface by simply controlling the descent speed of the tip 59 to be sufficiently slow. Therefore, according to this embodiment, since the supernatant can be continued to be aspirated at the liquid level Ls that is always the farthest from the solid-liquid interface, there is no need for control to determine the relationship between the liquid level Ls and the tip position Tp of the tip 59.

[0054] The liquid removal mechanism 5 stops the descent of the tip 59 when time T2 has elapsed since the tip 59 began to descend. At this time, the tip end position Tp of the tip 59 has reached the solid-liquid interface. With the tip end position Tp of the tip 59 having reached the solid-liquid interface, the liquid removal mechanism 5 continues to aspirate the supernatant for time T3. This causes the tip 59 to aspirate the small amount of supernatant remaining near the solid-liquid interface. The liquid removal mechanism 5 pulls up the tip 59 when time T3 has elapsed. Through the above control, all of the supernatant that has separated onto the solid-liquid interface is aspirated.

[0055] 4, when the pump 54 is ON, the tip position Tp of the tip 59 and the liquid level Ls are displaced while maintaining a substantially equal distance. However, the distance between them does not necessarily have to be equal. Furthermore, the magnitude of the negative pressure of the pump 54 at times T1, T2, and T3 may be the same or different.

[0056] In the present embodiment, an example has been described in which tip 59 is attached to nozzle 58 as one aspect of the suction tube. However, a suction tube that is not separated into nozzle 58 and tip 59 may also be applied to this embodiment.

[0057] In this embodiment, the pump 54 is turned on after the tip of the tip 59 is moved to the reference position, and the pump 54 is maintained in the on state from the time when the tip 59 is turned on until the suction of the supernatant at the solid-liquid interface is completed. However, the pump 54 may be turned off once just before the tip 59 is lowered from the reference position to the position of the solid-liquid interface, and then turned on when the tip 59 starts to be lowered from the reference position to the position of the solid-liquid interface. Alternatively, the pump 54 may be turned off once and then turned on once the tip 59 has completed moving from the reference position to the position of the solid-liquid interface.

[0058] In this embodiment, the tip of tip 59 is moved from the initial position to the immersion position, and then moved from the immersion position to the reference position. However, the initial position may be set to the immersion position. Alternatively, the tip of tip 59 may be moved from the initial position to the reference position immediately. <Flowchart showing the control of supernatant aspiration> 5 is a flowchart showing the control of aspirating the supernatant. The control of the process based on this flowchart is executed by the control unit 500 of the liquid removal mechanism 5.

[0059] The control unit 500 first captures image A of the solid-liquid interface (step S1). At this time, the tip of the tip 59 is in the initial position, so the tip 59 is not included in image A. Next, the control unit 500 moves the tip of the tip 59 from the initial position to the immersion position (step S2). More specifically, the control unit 500 moves the tip 59 to the immersion position using the drive mechanism 52. As a result, the tip of the tip 59 enters the supernatant.

[0060] Next, the control unit 500 captures an image B including the tip end of the tip and the solid-liquid interface at the immersion position (step S3). Next, the control unit 500 uses images A and B to identify the position of the solid-liquid interface and the position of the tip of the tip 59, and then calculates the distance from the tip of the tip 59 to the solid-liquid interface (step S4).

[0061] Next, the control unit 500 moves the tip of the tip 59 to a reference position (step S5). The reference position is set at a position a distance H upward from the solid-liquid interface. The control unit 500 calculates the movement distance required to guide the tip of the tip 59 to the reference position by subtracting H from the distance calculated in step S4. The control unit 500 moves the tip of the tip 59 to the reference position by lowering the tip 59 based on the calculated movement distance.

[0062] Next, the control unit 500 aspirates the supernatant while the tip of the tip 59 is held at the reference position (step S6). More specifically, the control unit 500 drives the pump 54 while the tip of the tip 59 is held at the reference position. This applies negative pressure to the inside of the tip 59, causing the supernatant to be aspirated by the tip 59.

[0063] Next, the control unit 500 determines whether time T1 has elapsed (step S7). Data on time T1 is stored in advance in the memory 502 of the control unit 500. Time T1 is, for example, the time required from when the tip 59 starts suction at the reference position until the liquid level reaches the reference level or drops to near the liquid level. Time T1 is adjusted at the design stage.

[0064] If time T1 has not elapsed, the control unit 500 returns to the process of step S6 and continues aspirating the supernatant. If time T1 has elapsed, the control unit 500 continues aspirating the supernatant while slowly lowering the tip 59 (step S8). The speed at which the tip 59 is lowered is, for example, sufficiently slow so that the tip of the tip 59 follows the liquid surface that descends as the supernatant is aspirated into the tip 59.

[0065] The control unit 500 also limits the descent speed of the tip 59 so that the tip 59 moves at such a speed. As a result, the tip of the tip 59 moves from the reference position toward the solid-liquid interface while remaining near the liquid surface. The control unit 500 may lower the tip 59 at a sufficiently slow speed so that the tip of the tip 59 follows the liquid surface that descends as the supernatant is sucked into the tip 59, or may lower the tip 59 at a speed slightly faster than the slow speed.

[0066] Next, the control unit 500 determines whether or not time T2 has elapsed (step S9). Data on time T2 is stored in advance in the memory 502 of the control unit 500. Time T2 is, for example, the time required for the tip 59 to reach the solid-liquid interface from the reference position. Time T2 is adjusted at the design stage.

[0067] If time T2 has not elapsed, the control unit 500 returns to the process of step S8 and continues to control the tip 59 to descend while aspirating the supernatant. If time T2 has elapsed, the control unit 500 stops the descent of the tip 59 and causes the tip 59 to continue aspirating the supernatant at the solid-liquid interface (step S10).

[0068] Next, the control unit 500 determines whether or not time T3 has elapsed (step S11). Data on time T3 is stored in advance in the memory 502 of the control unit 500. Time T3 is, for example, the time required for the tip 59 to aspirate the supernatant remaining on the solid-liquid interface when it reaches the solid-liquid interface. Time T3 is adjusted at the design stage.

[0069] If time T3 has not elapsed, the control unit 500 returns to the process of step S10 and continues to control the tip 59 to aspirate the supernatant at the position of the solid-liquid interface. If time T3 has elapsed, the control unit 500 stops the aspirating of the supernatant and raises the tip 59 (step S12). More specifically, the control unit 500 stops driving the pump 54 and causes the drive mechanism 52 to move the tip 59 to the initial position. The control unit 500 then ends the process based on this flowchart.

[0070] An experiment using Escherichia coli culture solution was carried out according to the procedure described in this embodiment. As a result, it was confirmed that the supernatant could be aspirated with such precision that the remaining supernatant was 100 μL or less. This embodiment can be applied to the automation of devices such as aspirators that remove the upper layer of liquid while leaving the precipitate.

[0071] Embodiment 2 Next, a description will be given of embodiment 2. Fig. 6 is a flowchart showing the control of aspirating the supernatant. The control of the process based on this flowchart is executed by the control unit 500 of the liquid removal mechanism 5.

[0072] In the first embodiment, the control unit 500 controls the movement of the tip 59 and the operation of the pump 54 based on times T1, T2, and T3 set at the time of design. In the second embodiment, the control unit 500 controls the movement of the tip 59 and the operation of the pump 54 based on the position of the tip 59 and the position of the liquid surface. The second embodiment differs from the first embodiment in this respect, but is otherwise similar to the first embodiment. In the second embodiment, the position of the tip 59 and the position of the liquid surface are detected based on an image captured by the camera 56, for example.

[0073] The second embodiment will be described with reference to the flowchart of Fig. 6. Control unit 500 first executes the processes of steps S1 to S5. These processes are similar to the processes of steps S1 to S5 in Fig. 5. Therefore, the description thereof will not be repeated here.

[0074] The processing of step S5 moves the tip of tip 59 to the reference position. Control unit 500 aspirates the supernatant while keeping the tip of tip 59 at the reference position (step S21). More specifically, control unit 500 drives pump 54 while keeping the tip of tip 59 at the reference position. This applies negative pressure inside tip 59, causing tip 59 to aspirate the supernatant.

[0075] Next, the control unit 500 determines whether the distance between the liquid level and the tip of the tip 59 is less than a first threshold value (step S22). As the suction of the supernatant progresses at the reference position, the liquid level descends and approaches the position of the tip of the tip 59. In the second embodiment, the control unit 500 lowers the tip 59 when the distance between the liquid level and the tip of the tip 59 becomes less than the first threshold value. The first threshold value is stored in advance in the memory 502 of the control unit 500. The control unit 500 may be configured so that the first threshold value can be set to any value.

[0076] If the distance between the liquid surface and the tip of tip 59 is not less than the first threshold, control unit 500 returns to the process of step S21 and continues aspirating the supernatant. If the distance between the liquid surface and the tip of tip 59 becomes less than the first threshold, control unit 500 continues aspirating the supernatant while slowly lowering tip 59 (step S23). This moves the tip of tip 59 from the reference position toward the solid-liquid interface.

[0077] While the tip 59 is being lowered, the control unit 500 determines whether the distance between the liquid level and the tip of the tip 59 is less than a second threshold value (step S24). When the tip 59 is lowered and the supernatant is aspirated by the tip 59, the position of the liquid level and the position of the tip of the tip 59 are lowered. In the second embodiment, the tip 59 is lowered while the distance from the tip of the tip 59 to the liquid level is limited to a range between the second threshold value and a third threshold value (where the second threshold value is less than the third threshold value).

[0078] Therefore, when the distance between the liquid surface and the front end of the tip 59 is less than the second threshold, the control unit 500 accelerates the descending speed of the tip 59 (step S25). On the other hand, when the distance between the liquid surface and the front end of the tip 59 exceeds the third threshold (YES in step S26), the control unit 500 decelerates the descending speed of the tip 59 (step S27).

[0079] For example, if it is desired to lower the tip 59 while maintaining the tip position of the tip 59 near the liquid surface, the third threshold value may be set to a smaller value. Note that the control unit 500 may determine whether the tip of the tip 59 is located within the supernatant or in contact with the liquid surface by detecting a change in pressure at the tip of the tip 59.

[0080] The second threshold and the third threshold are stored in advance in the memory 502 of the control unit 500. The control unit 500 may be configured so that the second threshold and the third threshold can be set to any value.

[0081] Next, the control unit 500 determines whether the tip of the tip 59 has reached the solid-liquid interface (step S28). If the tip of the tip 59 has not reached the solid-liquid interface, the control unit 500 continues the process of step S23. If the tip of the tip 59 has reached the solid-liquid interface, the control unit 500 stops the descent of the tip 59 and causes the tip 59 to continue aspirating the supernatant at the position of the solid-liquid interface (step S29).

[0082] Next, the control unit 500 determines whether or not the supernatant remaining on the solid-liquid interface has been aspirated (step S30). Specifically, the control unit 500 determines whether or not the liquid level has disappeared as a result of the liquid level reaching the solid-liquid interface. If the supernatant remaining on the solid-liquid interface has not been aspirated, the control unit 500 continues aspirating the supernatant (step S29). If the supernatant on the solid-liquid interface has been aspirated, the control unit 500 stops aspirating the supernatant and raises the tip 59 (step S31). The control unit 500 then ends the processing based on this flowchart.

[0083] In the above-described first and second embodiments, the procedure for aspirating the supernatant was described, with the aim of removing the supernatant from a culture sample separated into bacterial cells and the supernatant, and recovering the bacterial cells. However, it goes without saying that the present disclosure can also be applied to cases where the supernatant is aspirated with the aim of removing bacterial cells from a culture sample separated into bacterial cells and the supernatant, and recovering the supernatant. In this case, the position at which the supernatant is aspirated at time T3 in Figure 4 may be set slightly above the solid-liquid interface. This further prevents bacterial cells from being mixed into the supernatant to be recovered.

[0084] [Aspect] It will be understood by those skilled in the art that the above-described embodiment and its modifications are specific examples of the following aspects.

[0085] (Item 1) A pretreatment device according to one embodiment aspirates a liquid component from a culture sample separated into a liquid component and a solid component across a solid-liquid interface in a container as a pretreatment. The pretreatment device includes an aspirating tube for aspirating the liquid component, a pump for applying negative pressure to the aspirating tube, and a control unit for moving the aspirating tube under negative pressure toward the solid-liquid interface within the liquid component.

[0086] According to the pretreatment device described in item 1, it is possible to increase the amount of liquid components that can be aspirated from the culture sample while minimizing the inclusion of solid components in the aspirate.

[0087] (Item 2) In the pretreatment device described in item 1, the control unit holds the suction tube under negative pressure at a first position within the liquid component that is a first distance away from the solid-liquid interface toward the liquid surface of the culture sample, and in response to a predetermined condition for moving the suction tube being met, moves the suction tube under negative pressure within the liquid component toward the solid-liquid interface.

[0088] According to the pretreatment device described in paragraph 2, at least a portion of the liquid component present from the liquid surface to the first position can be aspirated before the suction tube, to which negative pressure is applied, is moved in the direction of the solid-liquid interface within the liquid component.

[0089] (Item 3) In the pretreatment device described in item 2, the control unit, in response to a predetermined condition being met, moves the suction tube with negative pressure applied from a first position to a second position toward the solid-liquid interface, and keeps the suction tube with negative pressure applied at the second position.

[0090] According to the pretreatment device described in paragraph 3, the liquid components present from the liquid surface to the first position can be sucked until a predetermined condition is met. Also, the liquid components can be sucked at a second position that is closer to the solid-liquid interface than the first position.

[0091] (Item 4) In the pretreatment device according to item 3, the predetermined condition includes the lapse of a set time.

[0092] According to the pretreatment device described in item 4, the liquid component present from the liquid surface to the first position can be sucked until the set time has elapsed.

[0093] (Item 5) In the pretreatment device according to item 3 or 4, the second position is a solid-liquid interface.

[0094] According to the pretreatment device described in item 5, the liquid component remaining near the solid-liquid interface can be sucked.

[0095] (Item 6) In the pretreatment device described in any one of Items 3 to 5, the control unit maintains the state in which negative pressure is applied to the aspirating tube within the liquid component until the aspirating tube is held in the second position.

[0096] According to the pretreatment device described in paragraph 6, liquid components can be efficiently sucked. Furthermore, because the negative pressure is continuously applied, the flow of liquid components due to suction can be stabilized compared to when the negative pressure is turned off and then on midway. As a result, it is possible to prevent solid components from being stirred up due to the flow of liquid components due to suction.

[0097] (Item 7) In the pretreatment device described in any one of Items 1 to 6, the control unit limits the moving speed of the suction tube so that the part of the suction tube that sucks the liquid component is aligned with the liquid surface of the liquid component that moves as the liquid component is sucked into the suction tube.

[0098] According to the pretreatment device described in item 7, by limiting the moving speed of the suction tube, it is possible to continue aspirating the liquid component at the liquid surface position that is always farthest from the solid-liquid interface. As a result, the simple control of limiting the moving speed can effectively prevent the solid component from being stirred up due to the influence of the flow of the liquid component caused by suction.

[0099] (Item 8) In the pretreatment device described in any one of Items 1 to 6, the control unit controls the distance between the position where the liquid component is sucked by the suction tube and the liquid surface of the liquid component when the suction tube, to which negative pressure is applied, is moved toward the solid-liquid interface within the liquid component.

[0100] According to the pretreatment device described in paragraph 8, it is possible to continue suction while maintaining the position at which the liquid component is aspirated by the suction tube slightly below the liquid surface, thereby enabling the liquid component to be aspirated efficiently.

[0101] (Item 9) A pretreatment method according to Item 9, in which a liquid component is aspirated by an aspirating tube from a culture sample separated into a liquid component and a solid component separated by a solid-liquid interface in a container as a pretreatment, includes the steps of applying negative pressure to the aspirating tube and moving the aspirating tube with the negative pressure applied in the direction of the solid-liquid interface within the liquid component.

[0102] According to the pretreatment method described in item 9, it is possible to increase the amount of liquid components that can be aspirated from the culture sample while minimizing the inclusion of solid components in the aspirate.

[0103] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0104] 1 sampling device, 2 pretreatment device, 3 liquid chromatograph mass spectrometer, 4 centrifugation mechanism, 5 liquid removal mechanism, 6 reagent supply mechanism, 7 stirring mechanism, 8 extraction mechanism, 10 automatic pretreatment system, 14 test tube, 50 mounting plate, 51 holding mechanism, 52 drive mechanism, 53 moving mechanism, 54 pump, 55 housing, 56 camera, 57 surface lighting, 58 nozzle, 59 tip, 500 control unit, 501 processor, 502 memory, 511 displacement unit, 531 shaft unit, 532 base unit, 533 recess, 551, 552 opening, Ls liquid level position, Tp tip position.

Claims

1. A pretreatment device that aspirates a liquid component from a culture sample that has been separated into a liquid component and a solid component across a solid-liquid interface in a container, as a pretreatment, a suction tube for suctioning the liquid component; a pump that applies negative pressure to the suction tube; a control unit that moves the suction tube in the negative pressure state toward the solid-liquid interface within the liquid component, The control unit the aspirating tube with the negative pressure applied is held at a first position in the liquid component that is a first distance away from the solid-liquid interface toward the liquid surface of the culture sample; a pretreatment device that, in response to a predetermined condition for moving the suction tube being satisfied, moves the suction tube in the negative pressure state within the liquid component toward the solid-liquid interface.

2. The control unit In response to the predetermined condition being satisfied, the suction tube in a state in which the negative pressure is being applied is moved from the first position to a second position facing the solid-liquid interface; The pretreatment device according to claim 1 , wherein the suction tube is held at the second position while the negative pressure is applied.

3. The pretreatment device according to claim 1 or 2, wherein the predetermined condition includes the lapse of a set time.

4. The pretreatment device according to claim 2 , wherein the second position is the solid-liquid interface.

5. The control unit The pretreatment device according to claim 2 or 4, wherein the state in which the negative pressure is applied to the suction tube is maintained from the time when the negative pressure is applied to the suction tube within the liquid component until the time when the suction tube is held at the second position.

6. The pretreatment device according to any one of claims 1 to 5, wherein the control unit limits the movement speed of the suction tube so that the part of the suction tube that sucks the liquid component is aligned with the liquid surface of the liquid component that moves as the liquid component is sucked into the suction tube.

7. The pretreatment device according to any one of claims 1 to 6, wherein the control unit controls the distance between the position at which the liquid component is sucked by the suction tube and the liquid surface of the liquid component when the suction tube, to which the negative pressure is applied, is moved toward the solid-liquid interface within the liquid component.

8. The pretreatment device according to any one of claims 1 to 7, wherein the control unit continuously moves the suction tube, with the negative pressure applied, from the first position to the solid-liquid interface within the liquid component.

9. A pretreatment method for aspirating a liquid component from a culture sample separated into a liquid component and a solid component across a solid-liquid interface in a container using an aspirator tube as a pretreatment, comprising: applying a negative pressure to the suction tube; moving the suction tube in the negative pressure state within the liquid component toward the solid-liquid interface; holding the aspirator tube with the negative pressure applied at a first position within the liquid component a first distance away from the solid-liquid interface toward the liquid surface of the culture sample; and in response to a predetermined condition for moving the suction tube being satisfied, moving the suction tube with the negative pressure applied within the liquid component toward the solid-liquid interface.

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