Sample preparation system and sample preparation method

Abstract

In a sample preparation system according to the present disclosure, a stock solution is diluted with a diluent to prepare a sample for liquid chromatograph analysis. The sample preparation system is provided with a needle and a control unit that controls the needle. The control unit causes the needle to execute first suction for sucking the stock solution, first discharge for discharging the sucked stock solution and the diluent into a container, second suction for sucking the stock solution and the diluent from the container at a first speed, and second discharge for discharging the sucked stock solution and diluent into the container at a second speed that is at least 10 times the first speed.

Description

Sample preparation system and sample preparation method

[0001] The present invention relates to a sample preparation system and a sample preparation method, and more particularly to a technique for shortening the time required to prepare a sample to be subjected to liquid chromatographic analysis.

[0002] When measuring the concentration of a component in a sample using a liquid chromatograph, the user may need to dilute the stock solution of the sample to prepare the sample for analysis.

[0003] Regarding the preparation of samples to be supplied to an analytical instrument, Shimadzu Corporation, "Automatic Dilution and Preparation of Standard and Sample Solutions Using the SIL-30AC," Technical Report No. 47 (C190-0360), April 2011 (Non-Patent Document 1), and Sonja Schipperges, "Automating Pipetting with an Autosampler," Publication No. 5994-1704JAJP, February 2020 (Non-Patent Document 2), disclose a technique in which dilution work is performed by an autosampler in a liquid chromatograph analytical instrument.

[0004] Shimadzu Corporation, "Automatic Dilution and Preparation of Standard and Sample Solutions Using the SIL-30AC," Technical Report No. 47 (C190-0360), April 2011. Sonja Schipperges, "Automating Pipetting with an Autosampler," Publication No. 5994-1704JAJP, February 2020.

[0005] According to the techniques disclosed in Non-Patent Documents 1 and 2, an autosampler performs a dilution operation. The dilution operation involves multiple steps, such as aspirating and discharging a solution using a needle, moving the needle, and mixing the solutions, and the dilution operation using an autosampler can take a significant amount of time. Therefore, there is a need to shorten the time required for the dilution operation to prepare a sample.

[0006] The present invention has been devised in view of the above circumstances, and its object is to provide a technique for shortening the time required to prepare a sample for liquid chromatographic analysis.

[0007] A sample preparation system according to a first aspect of the present disclosure is a sample preparation system that dilutes a stock solution with a diluent to prepare a sample for liquid chromatography analysis. The sample preparation system includes a needle that aspirates and dispenses the stock solution, and a controller that controls the needle. The controller causes the needle to perform a first suction to aspirate a required volume of the stock solution, a first discharge to dispense the stock solution aspirated by the first suction and the required volume of the diluent into a container, a second suction to aspirate the stock solution and the diluent from the container at a first speed, and a second discharge to dispense the stock solution and the diluent aspirated by the second suction into the container at a second speed that is at least 10 times faster than the first speed.

[0008] A sample preparation method according to a second aspect of the present disclosure is a method for preparing a sample for liquid chromatography analysis by diluting a stock solution with a diluent, the sample preparation method including the steps of (a) aspirating a required amount of the stock solution, (b) dispensing the aspirated required amount of the stock solution and the required amount of the diluent into a container, (c) aspirating the stock solution and the diluent from the container at a first speed, and (d) dispensing the aspirated stock solution and the diluent into the container at a second speed that is at least 10 times faster than the first speed.

[0009] According to the present disclosure, it is possible to reduce the time required to prepare a sample for liquid chromatographic analysis.

[0010] Fig. 1 is a schematic diagram showing the configuration of an analytical device according to an embodiment; Fig. 2 is a schematic diagram showing a state different from that of Fig. 1 in an analytical device according to an embodiment; Fig. 3 is a schematic diagram showing the configuration of a control device according to an embodiment; Fig. 4 is a diagram showing a calibration curve according to Verification Example 1; Fig. 5 is a diagram showing actual measured values ​​of dilution ratios according to Verification Example 2; Fig. 6 is a diagram for explaining a sample preparation process;

[0011] 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.

[0012] 1 is a diagram showing the configuration of an analysis device 100 according to an embodiment. In this embodiment, analysis device 100 will be described using a liquid chromatograph, but the present invention is not limited to this, and analysis device 100 may also be, for example, a liquid chromatograph mass spectrometer (LC-MS), a liquid chromatograph tandem mass spectrometer (LC-MS / MS), or a liquid chromatograph inductively coupled plasma mass spectrometer (LC-ICP-MS).

[0013] 1 , the analytical device 100 includes a mobile phase container 1, a liquid delivery pump 2, an autosampler 3, a column 4, a detector 5, a waste liquid container 6, a control device 7, and a diluent container 8. The analytical device 100 can separate multiple types of components contained in a sample into individual types of components by utilizing differences in interactions between the components and the stationary phase and the mobile phase.

[0014] The mobile phase container 1 stores a solvent M, which is a mobile phase that carries a sample injected into the analytical device 100. The solvent M is, for example, an organic solvent, an aqueous solution (or water), or a mixture thereof. The analytical device 100 may be provided with a single mobile phase container or multiple mobile phase containers.

[0015] The liquid delivery pump 2 sucks the solvent M stored in the mobile phase container 1 and delivers it at a predetermined flow rate. The flow rate of the solvent M delivered by the liquid delivery pump 2 is constant for each measurement. The analytical device 100 may be equipped with a single liquid delivery pump or multiple liquid delivery pumps.

[0016] The diluent container 8 stores a diluent D, which is a liquid for diluting the sample stock solution S. The diluent D is, for example, an organic solvent, an aqueous solution (or water), or a mixture thereof. The diluent D is also used as a cleaning liquid for the needle 32.

[0017] The autosampler 3 prepares samples for liquid chromatographic analysis and introduces the prepared samples into a flow path for analysis. The autosampler 3 includes a tray 31, a needle 32, a loop 33, a metering unit 34, an injection port 35, a valve 36, and a low-pressure valve 37.

[0018] 1, the common port of the low-pressure valve 37 is connected to the metering unit 34, and the selected port of the low-pressure valve 37 is connected to the port 366 of the valve 36 and the diluent container 8.

[0019] Containers containing liquids can be placed on tray 31. Tray 31 includes wells 311 and 312 for placing the containers. A container C1 containing a sample stock solution S is placed in well 311, and an empty container C2 is placed in well 312. The sample stock solution S is, for example, a biological sample, food, beverage, pharmaceutical, agricultural chemical, or environmentally derived liquid.

[0020] A sample for liquid chromatography analysis is prepared in container C2 by diluting a sample stock solution S with a diluent D. The shape and material of container C2 are not limited, but a shape that allows the dispensed liquid to be easily stirred is preferred. Therefore, container C2 preferably has a relatively small capacity and a rounded bottom. Container C2 is, for example, a 1 mL polypropylene container or a 150 μL glass container with a raised bottom.

[0021] The needle 32 has a tip and a base end, and is capable of aspirating and discharging liquid from the tip. The needle 32 is moved in the vertical direction and in the horizontal direction by a movement mechanism (not shown).

[0022] The loop 33 is a flow path for holding the liquid aspirated from the tip of the needle 32. The loop 33 is fluidly connected to the base end of the needle 32.

[0023] The metering unit 34 is configured to dispense and aspirate liquids or gases.

[0024] The injection port 35 has an opening for inserting the needle 32. The liquid injected from the injection port 35 is sent to the valve 36.

[0025] The valve 36 is used to switch the flow path configuration and includes six ports, ports 361 to 366. In this embodiment, the valve 36 is a six-port valve, but is not limited to this. Port 361 of the valve 36 is connected to a drain flow path (not shown), port 362 is connected to the injection port 35, port 363 is connected to the column 4, port 364 is connected to the liquid delivery pump 2, port 365 is connected to the loop 33, and port 366 is connected to the low-pressure valve 37.

[0026] The valve 36 can be switched between two states by switching the connections between the ports. Figure 2 is a diagram showing a state different from that shown in Figure 1, which is realized by switching the connections between the ports. The two states will be explained using Figures 1 and 2.

[0027] 1 , the first state is a state in which ports 361 and 362, ports 363 and 364, and ports 365 and 366 are connected. In this state, the solvent M in the mobile phase container 1 is pushed out by the liquid delivery pump 2 and delivered to the column 4. In addition, in the first state, the low-pressure valve 37 and the needle 32 are connected. Therefore, the measuring unit 34 can suck in and discharge liquid from the tip of the needle 32.

[0028] 2, the second state is a state in which ports 362 and 363, ports 364 and 365, and ports 366 and 361 are connected. In this state, solvent M in mobile phase container 1 is pushed out by pump 2, passes through loop 33, needle 32, and injection port 35, and is delivered to column 4. At this time, the sample stored in loop 33 is introduced into column 4 together with solvent M.

[0029] The column 4 is filled with a stationary phase, through which the mobile phase, solvent M, passes. As the sample passes through the column 4, it interacts with the mobile phase and stationary phase, causing multiple components in the sample to be separated in the time direction. Each component elutes from the outlet of the column 4 and is introduced into the detector 5.

[0030] The detector 5 sequentially detects the components separated and eluted by the column 4 and transmits the detected data to the control device 7. The solvent flowing out from the detector 5 is discharged into a waste liquid container 6. The solution flowing out from the detector 5 may be introduced into another analytical device (for example, a mass spectrometer).

[0031] The control device 7 is connected to the liquid delivery pump 2, autosampler 3, and detector 5, and controls the analytical device 100 while receiving chromatogram data detected by the detector 5. Note that the autosampler 3 is controlled by the control device 7 to prepare samples, and therefore the autosampler 3 and control device 7 correspond to one embodiment of a "sample preparation system."

[0032] The configuration of the control device 7 will be described with reference to Fig. 3. Fig. 3 is a schematic diagram showing the configuration of the control device 7.

[0033] The control device 7 includes a controller 70, an input unit 75, and an output unit 76. The input unit 75 and the output unit 76 are connected to the controller 70. The control device 7 is, for example, a computer. Note that the control device 7 does not need to be configured by a single computer, but may be configured by multiple computers. The operation of the control device 7 described in this embodiment may be performed in a distributed manner by multiple computers.

[0034] The controller 70 includes, as its main components, a processor 71, a memory 72, a communication interface (I / F) 73, and an input / output I / F 74. These components are connected to each other via a bus so as to be able to communicate with each other.

[0035] The processor 71 is an example of an electric circuit, and controls the operation of the control device 7 by executing a given program. The program executed by the processor 71 may be stored in the memory 72, or may be stored in a storage device external to the control device 7. The processor 71 is, for example, a CPU (Central Processing Unit).

[0036] The memory 72 can non-temporarily store the programs executed by the processor 71 and the chromatogram data obtained by the detector 5. The memory 72 includes volatile memory (e.g., RAM (Random Access Memory)) and non-volatile memory (e.g., ROM (Read Only Memory), a hard disk drive, and a solid state drive). The database and / or the programs may be stored in an external storage device accessible by the processor 71.

[0037] The communication I / F 73 is a communication interface for exchanging various data with external devices. The communication I / F 73 is realized by, for example, a network adapter. The communication method may be wireless communication such as Bluetooth (registered trademark) or wireless LAN, or wired communication using USB (Universal Serial Bus) or the like.

[0038] The input / output I / F 74 is an interface for exchanging various data between the processor 71 and an external device connected to the input / output I / F 74. The external device includes an input unit 75 and an output unit .

[0039] The input unit 75 accepts information input to the controller 70. This information includes, for example, the dilution ratio, the volume after dilution, the name of the sample, the type of sample, the position of the well in which the container C1 containing the undiluted sample S is placed, the position of the well in which the empty container C2 is placed, and analytical conditions. The analytical conditions include, for example, the flow rate of the mobile phase and the temperature of the column oven. The analytical conditions are conditions used when analyzing the obtained chromatogram, and include, for example, conditions for waveform processing and component identification. The input unit 75 is configured, for example, by a touch panel, a mouse, and / or a keyboard.

[0040] The output unit 76 displays information in accordance with instructions from the controller 70. The information may be, for example, chromatogram data detected by the detector 5, a created calibration curve, and calculated concentrations of components contained in the sample. The output unit 76 may be, for example, a liquid crystal display capable of displaying images.

[0041] Comparative Example When measuring the concentration of a component in a sample using a liquid chromatograph, the user may need to prepare the sample to be analyzed by diluting the undiluted sample solution.

[0042] Regarding diluting a stock solution of a sample to prepare a sample to be supplied to an analytical instrument, Non-Patent Documents 1 and 2 disclose a technique in which the dilution operation is performed by an autosampler of a liquid chromatograph analytical instrument.

[0043] According to the techniques disclosed in Non-Patent Documents 1 and 2, a user places a sample stock solution and a diluent used for dilution into the device, and the autosampler performs the dilution process. This reduces the burden on the user required for the dilution process. However, the dilution process involves multiple steps, such as aspirating and dispensing the solution with a needle, moving the needle, and mixing the solutions, and can be time-consuming.

[0044] For example, in both Non-Patent Document 1 and Non-Patent Document 2, the needle performs three suction and discharge operations to mix the stock solution and dilution solution of the sample dispensed into the container. If only one suction and discharge operation is performed to mix the sample, the time required for the dilution process is shortened, but the stock solution and dilution solution of the sample may not be mixed uniformly in the sample. In such cases, the accuracy of the measurement of the components contained in the sample may be reduced. Therefore, it is desirable to shorten the time required to prepare a sample in which the stock solution and dilution solution of the sample are mixed uniformly.

[0045] [Sample Dilution System According to an Embodiment] In a sample preparation system including an autosampler 3 and a control device 7 according to an embodiment, the sample stock solution S and diluent D are aspirated at a first speed, and the aspirated sample stock solution S and diluent D are dispensed into a container at a second speed that is at least 10 times faster than the first speed. This reduces the number of times the aspirating and dispensing steps are performed to mix the sample. Furthermore, by dispensing the sample into a container at the second speed, the sample stock solution S and diluent D are uniformly mixed in the dispensed sample. The sample preparation system according to an embodiment can shorten the time required to prepare a sample without reducing the degree of mixing of the sample stock solution S and diluent D.

[0046] Furthermore, the sample preparation system according to the embodiment can reduce the number of times the sample is dispensed to mix the sample, thereby improving the reproducibility of the dilution process. Generally, when a sample is dispensed from the tip of the needle, some of the sample may remain on the inner wall of the needle. In such cases, the prepared sample may differ from the user's desired dilution ratio and / or volume of the diluted sample. Therefore, by reducing the number of times the sample is aspirated and dispensed, the variation in the dilution ratio among multiple samples diluted in the dilution process can be reduced, improving reproducibility.

[0047] <Sample Preparation Method> The sample preparation method will be described below. Sample preparation is performed by a sample preparation system consisting of an autosampler 3 and a control device 7.

[0048] The control device 7 receives information necessary for the dilution operation from the user via the input unit 75. The information necessary for the dilution operation includes, for example, the dilution ratio, the volume after dilution, the position of the well in which the container C1 containing the undiluted sample S is placed, and the position of the well in which the empty container C2 is placed.

[0049] The control device 7 calculates the required amount of the sample stock solution S and the required amount of the diluent D based on the information required for the dilution operation received from the user.

[0050] The user places a container containing the sample stock solution S and an empty container in the wells of the tray 31 according to the information input to the input unit 75. In this embodiment, the container C1 containing the sample stock solution S is placed in the well 311, and the empty container C2 is placed in the well 312.

[0051] When port 365 and port 366 are connected (the state shown in Figure 1), the control device 7 sends diluent D from the diluent container 8 and retains the diluent D in the loop 33 and the pipeline from the loop 33 to the tip of the needle 32.

[0052] The control device 7 moves the needle 32 to the container C1 using a moving mechanism (not shown). The control device 7 switches the selected port so that the common port of the low-pressure valve 37 is connected to the port 366 of the valve 36. The control device 7 controls the measuring unit 34 to aspirate the calculated required amount of the sample stock solution S from the container C1 into the needle 32.

[0053] After the control device 7 has aspirated the sample stock solution S into the needle 32, it controls the metering unit 34 to aspirate air into the needle 32. The amount of air aspirated into the needle 32 depends on the inner diameter of the needle 32, and the needle 32 is caused to aspirate air so that the distance from the tip of the needle 32 to the liquid surface of the sample stock solution S inside the needle 32 is a predetermined distance. The predetermined distance is, for example, 4 to 5 mm. The volume of air aspirated is, for example, 0.1 to 1 μL. By providing air between the liquid surface of the sample stock solution S and the tip of the needle 32 inside the needle 32, it is possible to prevent the sample stock solution S aspirated from the needle 32 from leaking out when the needle 32 is moved.

[0054] The control device 7 moves the needle 32 to the container C2. Then, the control device 7 controls the measuring unit 34 to dispense the aspirated undiluted sample S and the calculated required amount of diluent D from the needle 32 into the container C2.

[0055] Next, the control device 7 causes the needle 32 to perform the operations of aspirating and discharging the sample stock solution S and the diluent D contained in the container C2 once each, thereby mixing the sample stock solution S and the diluent D.

[0056] First, the control device 7 causes the needle 32 to aspirate the sample stock solution S and diluent D contained in the container C2. Before aspirating, air is aspirated to prevent the aspirated sample stock solution S and diluent D from mixing with the diluent D held in the loop 33. The amount of air is, for example, 5 μL. At this time, the speed at which the needle 32 aspirates the sample stock solution S and diluent D contained in the container C2 is defined as a first speed. The first speed is, for example, preferably 3 μL / sec or less, and more preferably 1 to 2 μL / sec.

[0057] Next, the control device 7 causes the needle 32 to eject the sample stock solution S and diluent D aspirated at the first speed into the container C2 at a second speed that is at least 10 times faster than the first speed. The second speed is, for example, 30 to 150 μL / sec, and preferably 30 to 40 μL / sec.

[0058] Through the above operations, the sample preparation system can prepare a sample to be subjected to liquid chromatography analysis. The prepared sample is aspirated through needle 32 and held in loop 33. Next, needle 32 is connected to injection port 35, and in a state in which ports 364 and 365 are connected (the state shown in FIG. 2 ), solvent M is delivered from liquid delivery pump 2, and the sample held in loop 33 is introduced into column 4 together with solvent M.

[0059] According to the sample preparation method of the present disclosure, when preparing a sample to be subjected to liquid chromatography analysis, the number of times that the suction and discharge steps required to mix the stock solution of the sample with the diluent can be reduced, thereby shortening the time required for sample preparation.

[0060] In the above-described embodiment, the diluent D for diluting the sample stock solution S is supplied from the diluent container 8, but this is not limiting. For example, a container containing the diluent D may be placed in a well provided on the tray 31, and the diluent D in the container may be used to dilute the sample stock solution S. In this case, in the above-described sample preparation method, the control device 7 dispenses the required amount of diluent D into the container C2 using the needle 32, and then causes the needle 32 to aspirate the sample stock solution S and discharge the sample stock solution S into the container C2.

[0061] The analytical device 100 in this embodiment includes a mobile phase container 1 storing a solvent M used as a mobile phase and a diluent container 8 storing a diluent D used to dilute the stock sample solution S, but these may be the same container. In this case, the solvent M used as the mobile phase and the diluent D used to dilute the stock sample solution S are the same container.

[0062] In this embodiment, sample preparation is described as being performed by a sample preparation system including the autosampler 3 and the control device 7, but the present invention is not limited to this. Sample preparation may also be performed using, for example, a dispenser that allows a user to dispense liquid.

[0063] Verification Example 1 A standard sample is diluted using the sample preparation system according to the present disclosure to prepare a plurality of samples for liquid chromatographic analysis, and the linearity of the measured values ​​of these samples in the liquid chromatographic analysis is examined.

[0064] In Verification Example 1, a 250 mg / L aqueous caffeine solution is used as the stock solution of the sample, and ultrapure water is used as the dilution solvent.

[0065] The sample stock solution is diluted at dilution rates of 500, 200, 100, 50, 20, 10, and 5 to prepare samples using a sample preparation system consisting of an autosampler 3 and a control device 7. The prepared samples are introduced into a column 4, and chromatogram data for each sample is created by the control device 7 based on data obtained by the detector 5. The area values ​​in the created chromatogram data are used as the measured values ​​for each sample.

[0066] The control device 7 receives the dilution rate and the volume of the diluted sample from the user via the input unit 75. The volume of the diluted sample is, for example, 100 μL.

[0067] Based on the received dilution rate and the volume of the diluted sample, the control device 7 calculates the required volume of the original solution and the required volume of the dilution solution. For example, if the dilution rate is 100 times and the volume of the diluted sample is 100 μL, the required volume of the original solution is calculated to be 1 μL and the required volume of the dilution solution is calculated to be 99 μL.

[0068] 4 shows the caffeine concentration of each sample and the area of ​​the chromatogram obtained by liquid chromatography. Note that the caffeine concentrations of the samples diluted with a 250 mg / L caffeine solution at dilutions of 500, 200, 100, 50, 20, 10, and 5 correspond to 0.5 mg / L, 1.25 mg / L, 2.5 mg / L, 5 mg / L, 12.5 mg / L, 25 mg / L, and 50 mg / L, respectively.

[0069] In Figure 4, the horizontal axis represents the caffeine concentration, and the vertical axis represents the area value, which is the measured value of the corresponding sample. Figure 4 also shows a linear equation expressing the relationship between the caffeine concentration and the measured value. R is the correlation coefficient of the linear equation, and the closer the contribution rate or coefficient of determination, expressed as the square of the correlation coefficient, is to 1, the stronger the positive correlation.

[0070] 4, the contribution ratio is 0.9997. Therefore, it can be said that the sample prepared by the sample preparation system according to the present disclosure is prepared to the dilution ratio desired by the user.

[0071] Verification Example 2 The dilution rate and its variation of diluted samples prepared by diluting a stock sample solution using the sample preparation system according to the present disclosure were examined.

[0072] A sample preparation system including an autosampler 3 and a control device 7 prepares a sample by diluting a stock sample solution containing component X at a dilution rate of 50. The prepared sample is introduced into a column 4, and chromatogram data for each sample is prepared by the control device 7 based on data obtained by the detector 5. The area value of the peak derived from component X in the prepared chromatogram data is taken as the measured value of component X in each sample.

[0073] In this case, the six samples prepared with the first rate set to 1 μL / sec and the second rate set to 35 μL / sec were designated Group 1. The six samples prepared with the first rate set to 1 μL / sec and the second rate set to 1 μL / sec were designated Group 2.

[0074] Figure 5 shows the dilution ratios calculated from the chromatogram data obtained by analyzing each group of samples. In Figure 5, the vertical axis represents the ratio of the actual dilution ratio of the prepared sample to the set dilution ratio (50x). Therefore, the closer the value on the vertical axis is to 100%, the better the dilution accuracy relative to the set dilution ratio.

[0075] 5, the average measured dilution rate in Group 1 was 42.9, which is 85.8% of the set dilution rate of 50. On the other hand, the average measured dilution rate in Group 2 was 42.2, which is 84.5% of the set dilution rate of 50. Therefore, Group 1, which has a faster second speed, was diluted at a dilution rate closer to the set dilution rate than Group 2, which has a faster second speed.

[0076] In addition, in Figure 5, the error bars in each graph indicate the variability of the measured values ​​of the dilution ratio in each group. As shown in Figure 5, the variability of the measured values ​​of the dilution ratio in Group 1 is smaller than the variability of the measured values ​​of the dilution ratio in Group 2. Group 1, which has a faster second speed, has smaller variability in the dilution ratio of the prepared samples than Group 2, which has a faster second speed, and the reproducibility of the dilution operation is higher.

[0077] From the above, it can be said that the sample preparation system disclosed herein can dilute the sample at a dilution rate closer to the set dilution rate than when the second speed is slower than that of the sample preparation system, and furthermore, the reproducibility of the sample dilution process is high.

[0078] [Process Flow] Figure 6 shows a process for preparing a sample for liquid chromatographic analysis by diluting a stock solution of the sample. Of the steps shown in Figure 6, steps S10 and S12 relate to the operation of the control device 7 itself. Of the steps shown in Figure 6, steps S14 to S22 relate to the operation performed by the autosampler 3 controlled by the control device 7.

[0079] In step S10, the control device 7 receives the dilution rate and the volume of the diluted sample from the user via the input unit 75.

[0080] In step S12, the control device 7 calculates the amount of sample stock solution S and the amount of diluent D required to prepare the sample based on the dilution ratio and the volume of the diluted sample received in step S10.

[0081] In step S14, the control device 7 controls the autosampler 3 to move the needle 32 to the container C1 containing the sample stock solution S, and to aspirate the required amount of stock solution S calculated in step S12 into the needle 32. This operation is the first aspirating in one embodiment.

[0082] In step S16, the control device 7 causes the needle 32 to aspirate air so that the distance from the tip of the needle 32 to the liquid surface of the sample stock solution S is a predetermined distance. The predetermined distance is, for example, 4 to 5 mm. This prevents the stock solution S aspirated in step S14 from leaking out of the needle 32.

[0083] In step S18, the control device 7 moves the needle 32 to an empty container C2 and dispenses the necessary amount of stock solution S aspirated in step S14 and the necessary amount of diluent D calculated in step S12. The diluent D is supplied to the needle 32 from the diluent container 8 via the measuring unit 34. This operation is the first dispense in one embodiment.

[0084] In step S20, the control device 7 causes the needle 32 to aspirate the sample stock solution S and diluent D from the container C2 at a first speed. The first speed is preferably 3 μL / sec or less, and more preferably 1 to 2 μL / sec. In one embodiment, this operation is the second aspirating operation.

[0085] In step S22, the control device 7 causes the needle 32 to eject the sample stock solution S and diluent D aspirated in step S20 at a second speed that is at least 10 times faster than the first speed. The second speed is, for example, 30 to 150 μL / sec, and preferably 30 to 40 μL / sec. This operation is the second ejection in one embodiment.

[0086] By preparing a sample for liquid chromatography analysis according to the above process, the number of times of suction and discharge required to mix the undiluted sample solution and the diluted solution can be reduced, thereby shortening the time required for sample preparation.

[0087] Furthermore, by sucking air after sucking the undiluted sample solution, it is possible to prevent the undiluted sample solution from leaking from the tip of the needle while the needle is moving.

[0088] Aspects It will be understood by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0089] (Item 1) In one aspect, a sample preparation system dilutes a stock solution with a diluent to prepare a sample for liquid chromatography analysis. The sample preparation system includes a needle that aspirates and dispenses the stock solution, and a control unit that controls the needle. The control unit may cause the needle to perform a first suction to aspirate a required amount of the stock solution, a first discharge to dispense the stock solution aspirated by the first suction and a required amount of the diluent into a container, a second suction to aspirate the stock solution and the diluent from the container at a first speed, and a second discharge to dispense the stock solution and the diluent aspirated by the second suction into the container at a second speed that is at least 10 times faster than the first speed.

[0090] According to the preparation system described in paragraph 1, the time required to prepare a sample for liquid chromatographic analysis can be reduced.

[0091] (Item 2) In the sample preparation system described in item 1, the needle may be fluidly connected to a metering unit that supplies the diluent from a storage container that stores the diluent.

[0092] According to the preparation system described in paragraph 2, the diluent for diluting the sample is supplied from a metering unit that is fluidly connected to the needle.

[0093] (Clause 3) In the sample preparation system described in paragraph 1 or 2, the control unit may cause the needle to aspirate the required amount of diluent and dispense it into the container before performing the first suction.

[0094] According to the preparation system described in paragraph 3, a diluent for diluting the stock solution of the sample is prepared in an empty container before the needle aspirates the stock solution of the sample.

[0095] (4) In the sample preparation system described in any one of paragraphs 1 to 3, the control unit may cause the needle to aspirate air after performing the first suction.

[0096] According to the preparation system described in item 4, air is sucked in after the undiluted sample solution is sucked in, thereby preventing the undiluted sample solution from leaking out of the needle.

[0097] (Clause 5) In the sample preparation system described in paragraph 4, the control unit may, when aspirating air into the needle, aspirate the air so that the distance from the tip of the needle to the liquid surface of the original solution aspirated by the first suction is a predetermined distance.

[0098] According to the preparation system described in paragraph 5, after aspirating the sample concentrate, a predetermined distance is provided between the liquid surface of the sample concentrate in the needle and the tip of the needle, thereby preventing the sample concentrate from leaking out of the needle.

[0099] (Clause 6) In the sample preparation system described in any one of clauses 1 to 5, the control unit may receive a dilution rate and a volume after dilution, and calculate the required amount of original solution and the required amount of diluted solution.

[0100] According to the preparation system described in paragraph 6, the required amount of concentrate and the required amount of diluent are calculated based on the dilution ratio and the volume after dilution received by the control device.

[0101] (Item 7) In the sample preparation system according to any one of items 1 to 6, the second rate may be 30 to 40 μL / sec.

[0102] According to the preparation system described in item 7, the sample can be mixed by discharging the sample into the container at a rate of 30 to 40 μL / sec.

[0103] (Item 8) In one aspect, a sample preparation method is a method for preparing a sample for liquid chromatography analysis by diluting a stock solution with a diluent. The sample preparation method may include the steps of aspirating a required amount of the stock solution, dispensing the aspirated required amount of the stock solution and the required amount of the diluent into a container, aspirating the stock solution and the diluent from the container at a first speed, and dispensing the aspirated stock solution and the diluent into the container at a second speed that is at least 10 times faster than the first speed.

[0104] According to the sample preparation method described in paragraph 8, the time required to prepare a sample for liquid chromatographic analysis can be reduced.

[0105] (Clause 9) The sample preparation method described in Clause 8 may further include a step of aspirating and discharging the required volume of dilution liquid before the step of aspirating the required volume of stock solution is performed.

[0106] According to the sample preparation method described in paragraph 9, a diluent for diluting the stock solution of the sample is prepared in an empty container before the stock solution of the sample is aspirated.

[0107] (Item 10) The sample preparation method according to item 8 or 9 may further include a step of aspirating air after the step of aspirating the required amount of the stock solution is performed.

[0108] According to the sample preparation method described in paragraph 10, air is sucked in after the undiluted sample solution has been sucked in, thereby preventing the undiluted sample solution from leaking out.

[0109] (Clause 11) In the step of aspirating air in the sample preparation method described in Clause 10, the air may be aspirated so that the distance from the tip of the needle aspirating the stock solution to the liquid surface of the stock solution aspirated by the first suction is a predetermined distance.

[0110] According to the sample preparation method described in paragraph 11, after aspirating the sample concentrate, a predetermined distance is provided between the liquid surface of the sample concentrate in the needle and the tip of the needle, thereby preventing the sample concentrate from leaking.

[0111] (Item 12) In the sample preparation method according to any one of Items 8 to 11, the container may have a round bottom.

[0112] According to the sample preparation method described in paragraph 12, the container in which the sample is prepared has a round bottom, so that the efficiency of stirring the sample can be improved.

[0113] (Item 13) In the sample preparation method according to Item 12, the container may be a polypropylene container having a capacity of 1 mL, or a glass container having a capacity of 150 μL with a raised bottom.

[0114] According to the sample preparation method described in item 13, the container in which the sample is prepared is suitable for mixing the sample, and the efficiency of stirring the sample can be improved.

[0115] (Item 14) In the sample preparation method according to any one of Items 8 to 13, the second rate may be 30 to 40 μL / sec.

[0116] According to the sample preparation method described in item 14, the sample can be mixed by discharging the sample into the container at a rate of 30 to 40 μL / sec.

[0117] (Item 15) In the sample preparation method according to any one of items 8 to 14, each step may be performed by an autosampler that prepares the sample for liquid chromatographic analysis.

[0118] The sample preparation method described in paragraph 15 can be performed using an autosampler that prepares samples for liquid chromatographic analysis, eliminating the need for the user to manually perform the dilution process, thereby reducing the burden on the user associated with the dilution process.

[0119] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the description of the above-described embodiments, and is intended to include all modifications within the meaning and scope of the claims. Furthermore, it is intended that each technique in the embodiments can be implemented alone or, if necessary, in combination with other techniques in the embodiments to the extent possible.

[0120] 1 Mobile phase container, 2 Liquid delivery pump, 3 Autosampler, 4 Column, 5 Detector, 6 Waste liquid container, 7 Control device, 8 Dilution solution container, 31 Tray, 32 Needle, 33 Loop, 34 Metering unit, 35 Injection port, 36 Valve, 37 Low-pressure valve, 70 Controller, 71 Processor, 72 Memory, 73 Communication I / F, 74 Input / output I / F, 75 Input section, 76 Output section, 100 Analytical device.

Claims

1. A sample preparation system that dilutes a stock solution with a diluent to prepare a sample for liquid chromatography analysis, comprising: a needle that aspirates and discharges the stock solution; and a control unit that controls the needle, wherein the control unit causes the needle to: perform a first suction to aspirate a required amount of the stock solution; perform a first discharge to discharge the stock solution aspirated by the first suction and the required amount of diluent into a container; perform a second suction to aspirate the stock solution and the diluent from the container at a first speed; and perform a second discharge to discharge the stock solution aspirated by the second suction and the diluent into the container at a second speed that is at least 10 times faster than the first speed.

2. The sample preparation system of claim 1, wherein the needle is fluidly connected to a metering unit that dispenses the diluent from a reservoir that stores the diluent.

3. The sample preparation system of claim 1, wherein the control unit causes the needle to aspirate and dispense the required amount of diluent into the container before performing the first suction.

4. A sample preparation system according to any one of claims 1 to 3, wherein the control unit causes the needle to aspirate air after performing the first suction.

5. The sample preparation system described in claim 4, wherein the control unit aspirates air into the needle so that the distance from the tip of the needle to the liquid surface of the original solution aspirated by the first suction is a predetermined distance.

6. A sample preparation system according to any one of claims 1 to 3, wherein the control unit receives the dilution ratio and the volume after dilution, and calculates the required amount of original solution and the required amount of diluted solution.

7. A sample preparation system according to any one of claims 1 to 3, wherein the second rate is 30 to 40 μL / sec.

8. A sample preparation method for diluting a stock solution with a diluent to prepare a sample for liquid chromatographic analysis, comprising the steps of: aspirating a required amount of the stock solution; dispensing the aspirated required amount of the stock solution and the required amount of the diluent into a container; aspirating the stock solution and the diluent from the container at a first speed; and dispensing the aspirated stock solution and the diluent into the container at a second speed that is at least 10 times faster than the first speed.

9. The sample preparation method of claim 8, further comprising the step of aspirating and dispensing the required diluent volume before the step of aspirating the required stock volume of the stock solution is performed.

10. The sample preparation method according to claim 8 or claim 9, further comprising the step of aspirating air after the step of aspirating the required volume of the stock solution has been performed.

11. A sample preparation method as described in claim 10, wherein in the step of aspirating air, air is aspirated so that the distance from the tip of the needle aspirating the original solution to the liquid surface of the original solution aspirated in the step of aspirating the dilution solution at a first speed is a predetermined distance.

12. A sample preparation method according to claim 8 or claim 9, wherein the container has a round bottom.

13. The sample preparation method of claim 12, wherein the container is a polypropylene container having a capacity of 1 mL or a glass container having a capacity of 150 μL with a raised bottom.

14. The sample preparation method of claim 8 or claim 9, wherein the second rate is 30 to 40 μL / sec.

15. The sample preparation method of claim 8 or claim 9, wherein each step is performed by an autosampler that prepares the sample for liquid chromatographic analysis.

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