A liquid chromatography analysis system and gradient elution control method

Abstract

This application relates to the field of chromatographic analysis technology, and discloses a liquid chromatography analysis system and a gradient elution control method. The method, applied to a liquid chromatography analysis system, includes: responding to an injection command, controlling the injection pathway to open and controlling the injection device to deliver the sample to the sample buffer assembly; controlling the liquid phase pathway to connect with the remaining two interfaces besides the sample buffer assembly, and ensuring that the initial mobile phase flows through the pathway currently composed of the mobile phase delivery assembly, the switching assembly, and the chromatographic column; determining the start time of the delay volume time based on the injection time and the delay volume time; when the start time of the delay volume time is reached, making the mobile phase delivered through the gradient proportioning valve the target mobile phase; and when the end time of the injection time is reached, controlling the injection pathway to close and the liquid phase pathway to open, so that the sample in the sample buffer assembly is pushed into the chromatographic column by the target mobile phase at the zero point of the liquid phase gradient. The method of this application can eliminate the influence of the delay volume.

Description

Technical Field

[0001] This application relates to the field of chromatographic analysis technology, and in particular to a liquid chromatography analysis system and a gradient elution control method. Background Technology

[0002] Liquid chromatography (LC) is a commonly used analytical instrument that separates different components in a sample between a stationary phase and a mobile phase. In LC, it is sometimes necessary to change the composition of the mobile phase to achieve better sample separation. However, there is a time delay between the point where the mobile phase is mixed and the sample enters the column. This time delay affects the rate of gradient change, thus impacting the separation efficiency. A larger time delay results in a slower gradient change and a longer analysis time.

[0003] In existing technologies, the following methods are generally used to reduce the liquid phase delay volume:

[0004] First, optimize the solvent mixer and connecting pipes: select a smaller solvent mixer to reduce the volume occupied by the mixer itself; use thinner and shorter connecting pipes to reduce the volume within the connecting pipes, and within the pressure limit, choose pipes with small inner diameters and short lengths as much as possible. However, this method can only reduce the size of the delay volume, not eliminate its impact, and it also increases the difficulty of design layout and the pressure loss of the pipes.

[0005] Secondly, high-pressure pumps are used because they typically have a more compact design, reducing the contribution of pump volume to the delay volume, ensuring pump head sealing and efficiency, and avoiding unnecessary volume increases. However, this approach places higher demands on materials and seals, increases design complexity, and significantly raises product costs.

[0006] Third, consider gradient elution methods: In gradient elution, the gradient delay effect caused by the delay volume can be reduced by optimizing the rate and shape of the gradient change. This usually involves adjusting parameters of the gradient program, such as the gradient slope, the initial and target mobile phase ratios, etc. However, this method cannot eliminate the influence of the delay volume, and changing the rate and shape of the gradient change will affect the liquid phase separation efficiency, which is not conducive to the separation of compounds with high gradient requirements. Summary of the Invention

[0007] In view of this, embodiments of this application provide a liquid chromatography analysis system and a gradient elution control method, which can effectively eliminate the influence of delay volume on gradient analysis.

[0008] In a first aspect, embodiments of this application provide a liquid chromatography analysis system, including: a mobile phase supply component, a gradient proportioning valve, a mobile phase delivery component, a switching component, an injection device, a chromatographic column, and a detector;

[0009] The switching component includes an injection path and a liquid phase path; wherein the injection path and the liquid phase path share a sample buffer component, when the injection path is on, the liquid phase path is off from the sample buffer component, and when the liquid phase path is on, the injection path is off from the sample buffer component.

[0010] The inlet of the injection passage is connected to the injection device;

[0011] The mobile phase supply component, the gradient proportioning mixing valve, and the mobile phase delivery component are connected in sequence and connected to the inlet of the liquid phase passage of the switching component;

[0012] The outlet of the liquid phase pathway, the chromatographic column, and the detector are connected in sequence.

[0013] In some embodiments, the switching component is a six-way valve, which includes a first interface, a second interface, a third interface, a fourth interface, a fifth interface, a sixth interface, and a sample buffer component; wherein the sample buffer component is connected between the first interface and the fourth interface;

[0014] The sample introduction path is a path composed of the third interface, the fourth interface, the sample buffer component, the first interface, and the second interface;

[0015] The liquid phase pathway is a pathway composed of the fifth interface, the fourth interface, the sample buffer component, the first interface, and the sixth interface;

[0016] The mobile phase supply assembly, the gradient proportioning mixing valve, and the mobile phase delivery assembly are connected in sequence and connected to the fifth port of the six-way valve;

[0017] The injection device is connected to the third port of the six-way valve;

[0018] The sixth port of the six-way valve, the chromatographic column, and the detector are connected in sequence.

[0019] In some embodiments, the mobile phase supply assembly includes at least two separate solvent bottles and a degasser;

[0020] The degasser includes at least two sets of degassing interfaces, each set of degassing interfaces being connected to one of the solvent bottles and transmitting the liquid phase in the corresponding solvent bottle to the gradient proportioning mixing valve.

[0021] In some embodiments, the mobile phase delivery assembly includes a first delivery pump, a second delivery pump, and a mixer;

[0022] A one-way valve is installed on the pipeline before the first delivery pump and the second delivery pump, respectively;

[0023] The inlet of the mixer is connected to the outlet of the second delivery pump;

[0024] The outlet of the mixer is connected to the inlet of the liquid phase passage.

[0025] In some embodiments, the injection device includes a syringe, a sample vial, and an injection needle;

[0026] The syringe is used to control the injection needle to draw the sample from the sample vial and push it into the injection path.

[0027] In some embodiments, the system further includes a cleaning component;

[0028] The cleaning assembly includes a cleaning bottle for holding cleaning fluid;

[0029] When the sample introduction device is being cleaned, the second interface and the third interface are connected.

[0030] Secondly, embodiments of this application provide a gradient elution control method applied to the aforementioned liquid chromatography analysis system, comprising:

[0031] In response to the injection command, the injection pathway is controlled to open, and the injection device is controlled to deliver the sample to the sample buffer assembly; and

[0032] The liquid phase pathway is connected to two interfaces other than the sample buffer component, and the gradient proportioning valve is controlled according to a preset first proportioning parameter to ensure that the initial flow phase flows through the pathway currently composed of the mobile phase delivery component, the switching component, and the chromatographic column; and

[0033] The start time of the delay volume time is determined based on the injection time and the delay volume time.

[0034] When the start time of the delay volume time is reached, the gradient proportional mixing valve is controlled according to the preset second proportional parameter so that the flow phase delivered through the gradient proportional mixing valve is the target flow phase;

[0035] When the injection time ends, the injection path is disconnected and the liquid phase path is opened, so that the sample in the sample buffer assembly is pushed into the chromatographic column through the target mobile phase at the zero point of the liquid phase gradient.

[0036] In some embodiments, the injection time is calculated based on the aspiration time and the mechanical movement time, or calculated based on the aspiration time, the mechanical movement time, and the cleaning time; wherein, the aspiration time is the time it takes for the injection needle of the injection device to aspirate a sample each time; the mechanical movement time is the time from when the injection needle aspirates a sample to when the syringe of the injection device pushes the injection needle to deliver the sample in the injection needle to the sample buffer assembly; and the cleaning time is the time it takes to clean the injection needle.

[0037] The delay volume time is calculated based on the flow velocity of the mobile phase in the mobile phase delivery assembly and the delay volume; wherein, the delay volume is the sum of the internal space volume of the gradient proportional mixing valve and the mobile phase delivery assembly, plus the sum of the internal volumes of all pipelines between the gradient proportional mixing valve and the sample buffer assembly.

[0038] In some embodiments, controlling the opening of the sample injection path includes:

[0039] The first and second interfaces of the control switching component are connected, and the third and fourth interfaces are connected;

[0040] The control liquid phase pathway is connected to two interfaces other than the two interfaces connected to the sample buffer component, including:

[0041] The first and sixth interfaces of the control switching component are disconnected, the fourth and fifth interfaces are disconnected, and the fifth and sixth interfaces are connected.

[0042] In some embodiments, controlling the sample injection path to be disconnected and the liquid phase path to be connected includes:

[0043] The first and second interfaces of the control switching component are disconnected, as are the third and fourth interfaces.

[0044] It also controls the connection between the first and sixth interfaces, the connection between the fourth and fifth interfaces, and the disconnection between the fifth and sixth interfaces.

[0045] The embodiments of this application have the following beneficial effects: Upon receiving an injection command, this application controls the injection channel to open, thereby initiating sample delivery to the sample buffer assembly. Simultaneously, it begins delivering the initial mobile phase to the mobile phase delivery assembly, switching assembly, and the current flow path of the chromatographic column. It also determines the start time of the delay volume time. Upon reaching the start time of the delay volume, the gradient proportioning valve is controlled according to a preset second proportional parameter to begin delivering the target mobile phase to the mobile phase delivery assembly, switching assembly, and the current flow path of the chromatographic column. At the end of the injection, the injection path is disconnected, and the liquid phase path is opened. Since the end time of the injection time and the end time of the delay volume time are the same, meaning that the delay volume is filled with the target mobile phase at the moment of injection completion, it ensures that at the end of the injection, the target mobile phase directly propels the sample in the sample buffer assembly into the chromatographic column for analysis at the zero point of the liquid phase gradient. By determining the delivery time of the target mobile phase through the injection time and delay volume time in this application, the influence of the delay volume on the gradient time is eliminated, thereby optimizing the separation effect and improving analytical efficiency. Attached Figure Description

[0046] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 A first structural schematic diagram of a liquid chromatography analysis system according to an embodiment of this application is shown;

[0048] Figure 2 A second structural schematic diagram of the liquid chromatography analysis system according to an embodiment of this application is shown;

[0049] Figure 3 A schematic flowchart of a gradient elution control method according to an embodiment of this application is shown;

[0050] Figure 4 A timing diagram of gradient elution according to an embodiment of this application is shown.

[0051] Explanation of key component symbols:

[0052] 100 - Mobile phase supply assembly; 200 - Gradient proportioning mixing valve; 300 - Mobile phase delivery assembly; 400 - Switching assembly; 500 - Injection device; 600 - Chromatographic column; 700 - Detector; 110 - Solvent bottle; 120 - Degasser; 310 - First delivery pump; 320 - Second delivery pump; 330 - Mixer; 410 - Sample buffer assembly; 510 - Syringe; 520 - Sample bottle; 530 - Injection needle; 610 - Cleaning bottle. Detailed Implementation

[0053] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0054] The components of the embodiments of this application described and illustrated in the accompanying drawings can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0055] In the following text, the terms "comprising," "having," and their cognates, which may be used in various embodiments of this application, are intended only to indicate a particular feature, number, step, operation, element, component, or combination thereof, and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations thereof, or adding the possibility of one or more combinations thereof. Furthermore, the terms "first," "second," "third," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0056] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of this application pertain. Terms (such as those defined in commonly used dictionaries) shall be interpreted as having the same meaning as in their contextual meaning in the relevant technical field and shall not be construed as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of this application.

[0057] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0058] Liquid chromatography (LC) separates different components in a sample by utilizing the difference in their partition coefficients between the stationary and mobile phases. The stationary phase is a porous particulate material packed within the chromatographic column, while the mobile phase is the solvent carrying the sample through the column. Because different components exhibit varying interaction forces between the stationary and mobile phases, their migration velocities within the column differ, thus achieving separation. Gradient elution is an important technique in LC separation. During gradient elution, the composition of the mobile phase can vary within a certain range (e.g., 0%-100%). For example, within 60 minutes, the mobile phase ratio can change from methanol:water = 1:99 to methanol:water = 100:0. This change gradually increases the polarity of the mobile phase, enabling the separation of compounds with different polarities.

[0059] The liquid chromatography delay volume (also known as the gradient delay volume or retention volume) primarily refers to the volume between the solvent mixing point (usually within the mixing chamber of the liquid chromatograph, in tubing, or in a proportioning valve) and the inlet of the sample buffer assembly. This volume plays a crucial role in liquid chromatography systems, especially in gradient elution methods, where the size of the delay volume directly affects the rate of gradient change. A smaller delay volume allows for faster application of the adjusted mobile phase to the column, thus influencing the change in the mobile phase ratio within the column, and consequently affecting resolution and analysis time.

[0060] The following is combined with Figure 1 , Figure 2 The liquid chromatography analysis system of this embodiment will be described.

[0061] like Figure 1 As shown, the liquid chromatography analysis system includes a mobile phase supply component 100, a gradient proportioning valve 200, a mobile phase delivery component 300, a switching component 400, an injection device 500, a chromatographic column 600, and a detector 700.

[0062] The switching component 400 includes an injection path and a liquid phase path; the injection path and the liquid phase path share a sample buffer component 410. When the injection path is active, the liquid phase path is disconnected from the sample buffer component 410; when the liquid phase path is active, the injection path is disconnected from the sample buffer component 410. The inlet of the injection path is connected to the injection device 500. The mobile phase supply component 100, the gradient proportioning valve 200, and the mobile phase delivery component 300 are sequentially connected and connected to the inlet of the liquid phase path of the switching component 400. The outlet of the liquid phase path, the chromatographic column 600, and the detector 700 are sequentially connected. The gradient proportioning valve 200 is used to mix the liquid solvent delivered from the mobile phase supply component 100 into a preset proportion of liquid phase. The sample buffer component 410 can be, but is not limited to, a quantitative loop, a flow seat, or other structure capable of buffering samples.

[0063] The mobile phase supply assembly 100 includes at least two independent solvent bottles 110 and a degasser 120. The degasser 120 includes at least two sets of degassing interfaces, each set of interfaces connecting to one solvent bottle 110 and transferring the liquid phase in the corresponding solvent bottle 110 to the gradient proportioning mixing valve 200. It is understood that each solvent bottle 110 in the mobile phase supply assembly 100 contains a different liquid solvent, which can be water, methanol, acetonitrile, or other suitable solvents. The degasser 120 is used to remove gas from the liquid solvent supplied from the solvent bottle 110.

[0064] The mobile phase delivery assembly 300 includes a first delivery pump 310, a second delivery pump 320, and a mixer 330. A one-way valve is installed on the pipelines before the first delivery pump 310 and the second delivery pump 320 to prevent backflow of the liquid solvent delivered from the first delivery pump 310 and the second delivery pump 320. The inlet of the mixer 330 is connected to the outlet of the second delivery pump 320; the outlet of the mixer 330 is connected to the inlet of the liquid phase passage. Both the first delivery pump 310 and the second delivery pump 320 are plunger pumps; the use of two pumps in this embodiment prevents liquid phase flow interruption.

[0065] The switching component 400 is a six-way valve, which includes a sample buffer component 410 and six interfaces, corresponding sequentially to... Figure 1 and Figure 2 Interfaces a, b, c, d, e, and f are shown in the diagram. The sample buffer assembly 410 is connected between the first and fourth interfaces; the injection path is a pathway consisting of the third interface, the fourth interface, the sample buffer assembly 410, the first interface, and the second interface; the liquid phase pathway is a pathway consisting of the fifth interface, the fourth interface, the sample buffer assembly 410, the first interface, and the sixth interface; the mobile phase supply assembly 100, the gradient proportioning valve 200, and the mobile phase delivery assembly 300 are sequentially connected and connected to the fifth interface of the six-way valve; the injection device 500 is connected to the third interface of the six-way valve; the sixth interface of the six-way valve, the chromatographic column 600, and the detector 700 are sequentially connected.

[0066] In the liquid chromatography analysis system of this embodiment, solvent bottle 110 is used to provide liquid phase. The liquid phase passes sequentially through degasser 120, gradient proportioning valve 200, check valve, first delivery pump 310, second delivery pump 320, and mixer 330 before entering the six-way valve. Since the liquid chromatography analysis system needs to analyze samples, the sample to be analyzed must first be sent to sample buffer assembly 410, which is located between the first and fourth ports of the six-way valve. During injection, the second port of the six-way valve is connected to the first port, and the third port is connected to the fourth port. Injection device 500 is connected to the third port of the six-way valve, and the injection device 500 pushes the sample into sample buffer assembly 410 through the third port of the six-way valve.

[0067] After the sample buffer assembly 410 is filled with sample, the fourth port of the six-way valve is connected to the fifth port of the six-way valve, and the first port of the six-way valve is connected to the sixth port of the six-way valve. In this way, the liquid phase entering from the mixer 330 through the fifth port of the six-way valve can drive the sample chromatographic column 600 in the sample buffer assembly 410 for separation.

[0068] In some embodiments, the sample delivery device 500 includes a syringe 510, a sample vial 520, and a needle 530. When it is necessary to deliver a sample to the sample buffer assembly 410, the syringe 510 pushes the needle 530 to draw a sample from the sample vial 520 through the needle 530, and then the syringe 510 pushes the drawn sample into the sample buffer assembly 410.

[0069] In some embodiments, the liquid chromatography analysis system may be a liquid chromatography analysis system with a quaternary low-pressure liquid chromatography system.

[0070] The liquid chromatography system of the quaternary low-pressure liquid chromatography system includes four solvent bottles 110 (as shown in the figure, including solvent bottles 110A, 110B, 110C, and 110D). In this liquid chromatograph, the number of interfaces of its degasser 120 corresponds one-to-one with that of the solvent bottles 110, and each degasser 120 is connected to one interface of the degasser 120. After the gas in the liquid is removed by the degasser 120, it enters the gradient proportioning mixing valve 200. The number of interfaces of the gradient proportioning mixing valve 200 is also the same as that of the solvent bottles 110. That is, the liquid phase from each interface of the degasser 120 is transferred to the mixer 330 through the first transfer pump 310 and the second transfer pump 320. After the liquid phase is mixed evenly in the mixer 330, it is transferred to the six-way valve.

[0071] The four solvent bottles 110 each contain a different solvent or mobile phase, such as water, methanol, acetonitrile, or other suitable solvents. A gradient proportioning valve 200 mixes different solvents according to a set ratio to form the desired mobile phase proportion. A mixer 330 further homogenizes the solvents to ensure a uniform composition of the mixed mobile phase. A pump is used to push the mobile phase mixed by the gradient proportioning valve 200 into the mixer 330. The pump in the quaternary low-pressure system is typically a constant flow pump, providing a stable mobile phase flow rate.

[0072] In some embodiments, the liquid chromatography analysis system can be a binary high-pressure system liquid chromatography analysis system. The difference between this binary high-pressure system liquid chromatography analysis system and the aforementioned quaternary low-pressure system liquid chromatograph lies in the number of solvent bottles 110, the degasser 120, and the gradient proportioning valve 200. In the binary high-pressure system liquid chromatograph, there are two independent solvent bottles 110, the two ports of the degasser 120 are connected to the two solvent bottles 110 respectively, and the gradient proportioning valve 200 also has two ports, each connected to the corresponding port of the degasser 120. The remaining components are the same as in the above embodiments and will not be described again here.

[0073] In some embodiments, the system further includes a cleaning assembly; the cleaning assembly includes a cleaning bottle 610 for holding cleaning fluid; when cleaning the injection device 500, the second and third interfaces are connected, the first and second interfaces are disconnected, and the third and fourth interfaces are disconnected. The cleaning bottle 610 can also be connected to a degasser 120. After the previous chromatographic analysis, before the next chromatographic analysis, the injection needle 530 needs to be cleaned. The cleaning fluid in the cleaning bottle 610 is first degassed by the degasser 120, and then passes through the passage formed by the second and third interfaces to clean the injection needle 530.

[0074] According to the above-mentioned liquid chromatography analysis system, its liquid phase delay volume is the internal space volume of components such as gradient proportioning mixing valve 200, check valve, first delivery pump 310, second delivery pump 320, mixer 330, etc., plus the internal volume of all pipelines from gradient proportioning mixing valve 200 to sample buffer assembly 410.

[0075] Based on the above-mentioned liquid chromatography analysis system, this gradient elution control method will be explained with reference to some specific embodiments.

[0076] Figure 3 A schematic flowchart of a gradient elution control method according to an embodiment of this application is shown.

[0077] Exemplary, this gradient elution control method includes the following steps:

[0078] In step S100, in response to the injection command, the injection path is controlled to open, and the injection device is controlled to deliver the sample to the sample buffer component.

[0079] Step S200: Control the two interfaces of the liquid phase pathway, except for the sample buffer component, to be connected, and control the gradient ratio mixing valve according to the preset first ratio parameter so that the initial flow phase flows in the pathway composed of the mobile phase delivery component, the switching component, and the current column.

[0080] Step S300: Determine the delay time based on the injection time and the delay volume time.

[0081] It is understandable that steps S100, S200 and S300 are not in any particular order; they are all steps executed after the liquid chromatography analysis system receives the injection command.

[0082] After the liquid chromatography analysis system receives the injection command, it indicates that it wants to perform chromatographic analysis on the sample. Normally, when chromatographic analysis is required, in order to avoid the residue on the injection needle from affecting the sample, the injection needle is cleaned before step S100. During cleaning, the second interface and the third interface are connected. The cleaning solution in the cleaning bottle passes through the degasser and then cleans the injection needle through the passage formed by the second interface and the third interface.

[0083] After cleaning the injection needle, the injection pathway is opened, allowing the injection device to deliver the sample to the sample buffer assembly. Simultaneously, the remaining two ports in the liquid chromatography pathway (excluding the two ports connected to the sample buffer assembly) are also opened. This allows the initial mobile phase to flow through the gradient proportioning valve, mobile phase delivery assembly, switching assembly, and column in the currently configured channel. However, there is no sample at this point, so the column does not need to analyze it, and no detector is required. The initial mobile phase is obtained by controlling the gradient proportioning valve according to a preset first ratio parameter. For example, if the mobile phase supply assembly includes two independent solvent bottles, one for water and one for methanol, and the initial mobile phase has a water-to-methanol ratio of 99:1, then the gradient proportioning valve will be controlled to ensure that the mixed mobile phase is a 99:1 water-to-methanol mobile phase.

[0084] In some implementations, the switching component is a six-way valve, which controls the opening of the injection path and the delivery of the sample to the sample buffer assembly by the injection device. Specifically, it controls the connection of the first and second interfaces, and the connection of the third and fourth interfaces of the switching component. Additionally, the injection device is connected to the third interface of the six-way valve. After the injection path is connected, the injection device can be controlled to deliver the sample to the sample buffer assembly.

[0085] The control liquid phase pathway is connected to the remaining two interfaces besides the two interfaces connected to the sample buffer component. Specifically, the first and sixth interfaces of the control switching component are disconnected, the fourth and fifth interfaces are disconnected, and the fifth and sixth interfaces are connected. It can be understood that the liquid phase pathway needs to be disconnected at this point, but the fifth and sixth interfaces need to be connected so that the initial mobile phase can flow through the pathway formed by the mobile phase delivery component, the fifth and sixth interfaces, and the chromatographic column.

[0086] In some implementations, the delay time in step S300 is the injection time of the target mobile phase. Specifically, the delay volume time is calculated based on the flow rate of the mobile phase in the mobile phase delivery assembly and the delay volume. With the liquid chromatography analysis system fixed, the flow rate can be determined based on pre-test conditions. Furthermore, the delay volume is the sum of the internal volume of the gradient proportioning valve and the mobile phase delivery assembly, plus the volume of all pipelines between the gradient proportioning valve and the sample buffer assembly. Since the liquid chromatography analysis system is fixed, the delay volume can also be determined. Therefore, with the delay volume and flow rate determined, the delay volume time can be calculated using the following formula:

[0087] In the formula, T y Let S be the time of the delay volume, S be the delay volume, and V be the flow velocity.

[0088] The injection time is calculated based on the sampling time and mechanical movement time, or based on the sampling time, mechanical movement time, and cleaning time.

[0089] In this embodiment, with the liquid chromatography analysis system fixed, the sample injection device is also fixed. The sample injection device is as follows: Figure 2 As shown, the device includes a syringe, sample vial, and injection needle. The aspiration time is the time it takes for the injection needle to aspirate a sample each time. The mechanical movement time is the time from when the injection needle aspirates a sample to when the syringe pushes the injection needle to deliver the sample from the injection needle to the sample buffer assembly. The cleaning time is the time it takes to clean the injection needle. The aspiration time, mechanical movement time, and cleaning time can all be obtained through prior experiments.

[0090] If the injection needle does not need to be cleaned, the injection time is calculated based on the aspiration time and the mechanical movement time. That is, based on the capacity of the injection needle and the capacity of the sample buffer component, it is determined how many times the injection needle needs to aspirate, and thus the number of mechanical movements can also be obtained. The injection time can then be obtained by adding the multiple aspiration times and multiple mechanical movement times.

[0091] If the injection needle needs to be cleaned, the injection time is calculated based on the aspiration time, mechanical movement time, and cleaning time. That is, based on the capacity of the injection needle and the capacity of the sample buffer component, it is determined how many times the injection needle needs to aspirate, and thus the number of mechanical movements can also be obtained. The injection time can then be obtained by adding the multiple aspiration times, the multiple mechanical movement times, and the cleaning time.

[0092] After obtaining the injection time and delay volume time, such as Figure 4 As shown, the start time of the delay volume (time T1) can be obtained by subtracting the delay volume time (time T1 to T2) from the injection time (time T0 to T2). Figure 4 As shown, the end time of the injection time and the end time of the delay volume time are the same, that is, both are time T2.

[0093] In step S400, when the start time of the delay volume time is reached, the gradient proportional mixing valve is controlled according to the preset second proportional parameter so that the mobile phase delivered through the gradient proportional mixing valve is the target mobile phase.

[0094] The preset second proportional parameter is designed to ensure that the mobile phase achieves a mixing ratio of at least two solvents that constitute the target mobile phase. During chromatographic analysis of a sample, the proportions of the solvents in the target mobile phase are not necessarily fixed and can vary. Therefore, in this step, the preset second proportional parameter also varies. When controlling the gradient proportional mixing valve, the valve must be controlled according to the variation pattern of the preset second proportional parameter to ensure that the target mobile phase meets the changing requirements.

[0095] In step S500, when the injection time ends, the injection path is disconnected and the liquid phase path is opened, so that the sample in the sample buffer assembly is pushed into the chromatographic column through the target mobile phase at the zero point of the liquid phase gradient.

[0096] The zero point of the liquid phase gradient is the instant when the gradient program begins to execute. At this moment, the proportion of the mobile phase begins to change, that is, the starting point of the change from the initial proportion of the mobile phase to the target proportion of the mobile phase.

[0097] Before the injection time ends, the injection pathway is open, while the liquid phase pathway is closed. Specifically, the second, first, sample buffer, fourth, and third ports of the six-way valve are connected, as are the fifth and sixth ports. At the end of the injection time, the injection is complete, and the target mobile phase has filled the delay volume. At this point, the injection pathway is closed, and the liquid phase pathway is open. Specifically, the first and second ports are closed, as are the third and fourth ports. The sixth, first, quantitative exchange, fourth, and fifth ports are connected. This ensures that at the zero point of the liquid phase gradient, the target mobile phase directly propels the sample in the sample buffer into the chromatographic column for analysis, thus eliminating the influence of the delay volume. In this way, the actual analysis time for the sample is the injection time plus the gradient time (T2-T3), which is the time from T0 to T3, eliminating the delay volume time.

[0098] This application, upon receiving an injection command, controls the injection channel to open, thereby initiating sample delivery to the sample buffer assembly. Simultaneously, it begins delivering the initial mobile phase to the mobile phase delivery assembly, switching assembly, and the current flow path of the chromatographic column. The start time of the delay volume is also determined. Upon reaching the start time of the delay volume, the gradient proportioning valve is controlled according to a preset second proportional parameter to begin delivering the target mobile phase to the mobile phase delivery assembly, switching assembly, and the current flow path of the chromatographic column. At the end of the injection, the injection path is disconnected, and the liquid chromatography path is opened. Since the end time of the injection time and the end time of the delay volume coincide, the delay volume is already filled with the target mobile phase at the moment of injection completion. This ensures that at the end of the injection, the target mobile phase directly propels the sample in the sample buffer assembly into the chromatographic column for analysis at the zero point of the liquid chromatography gradient. By determining the target mobile phase delivery time through the injection time and delay volume time, the influence of the delay volume on the gradient time is eliminated, thereby optimizing the separation effect and improving analytical efficiency. Furthermore, by employing the method described in this application to eliminate the influence of delayed volume on gradient time, the original structure of the liquid phase analysis system does not need to be changed, and hardware costs will not increase.

[0099] This application also provides a terminal device, exemplary of which includes a processor and a memory, wherein the memory stores a computer program, and the processor executes the above-described gradient elution control method by running the computer program.

[0100] The processor can be an integrated circuit chip with signal processing capabilities. The processor can be a general-purpose processor, including at least one of a Central Processing Unit (CPU), Graphics Processing Unit (GPU), Network Processor (NP), Digital Signal Processor (DSP), Application-Specific Integrated Circuit (ASIC), Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor can be a microprocessor or any conventional processor, capable of implementing or executing the methods, steps, and logic block diagrams disclosed in the embodiments of this application.

[0101] The memory can be, but is not limited to, Random Access Memory (RAM), Read Only Memory (ROM), Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), etc. The memory is used to store computer programs, and the processor can execute the computer programs accordingly after receiving execution instructions.

[0102] This application also provides a computer-readable storage medium for storing the computer program used in the aforementioned terminal device. For example, the computer-readable storage medium may include, but is not limited to, various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0103] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that, in alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and combinations of blocks in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0104] In addition, the functional modules or units in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0105] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a smartphone, personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application.

[0106] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method of controlling a gradient elution, characterized by, Applied to a liquid chromatography analysis system, comprising: In response to a sample injection instruction, a sample injection passage is controlled to be turned on, and a sample injection device is controlled to deliver a sample into a sample buffer assembly; and A liquid phase passage is controlled to be in communication with two interfaces other than the sample buffer assembly, and a gradient proportioning valve is controlled according to a preset first proportioning parameter, so that an initial mobile phase flows in a passage currently composed of a mobile phase delivery assembly, a switching assembly and a chromatographic column; and A start time of the delay volume time is determined according to a sample injection time and the delay volume time; wherein the start time of the delay volume time is the sample injection time minus the delay volume time; When the start time of the delay volume time is reached, the gradient proportioning valve is controlled according to a preset second proportioning parameter, so that a mobile phase delivered through the gradient proportioning valve is a target mobile phase; When an end time of the sample injection time is reached, the sample injection passage is controlled to be turned off and the liquid phase passage is controlled to be turned on, so that the sample in the sample buffer assembly is pushed into the chromatographic column by the target mobile phase at a zero point of a liquid phase gradient; Wherein, the sample injection time is obtained according to a sample suction time and a mechanical movement time, or is obtained according to the sample suction time, the mechanical movement time and a cleaning time; the delay volume time is obtained according to a flow speed of the mobile phase in the mobile phase delivery assembly and the delay volume; Wherein, the liquid chromatography analysis system comprises a mobile phase supply assembly, a gradient proportioning valve, a mobile phase delivery assembly, a switching assembly, a sample injection device, a chromatographic column and a detector; the switching assembly comprises a sample injection passage and a liquid phase passage; wherein the sample injection passage and the liquid phase passage share a sample buffer assembly, the liquid phase passage is disconnected from the sample buffer assembly when the sample injection passage is turned on, and the sample injection passage is disconnected from the sample buffer assembly when the liquid phase passage is turned on; an inlet of the sample injection passage is in communication with the sample injection device; the mobile phase supply assembly, the gradient proportioning valve and the mobile phase delivery assembly are sequentially in communication and are in communication with an inlet of the liquid phase passage of the switching assembly; an outlet of the liquid phase passage, the chromatographic column and the detector are sequentially in communication.

2. The gradient elution control method according to claim 1, characterized by, The sample suction time is a time for the sample injection needle of the sample injection device to suck a sample each time, the mechanical movement time is a time for the sample injection needle to suck the sample each time to the syringe of the sample injection device to push the sample in the sample injection needle to the sample buffer assembly, and the cleaning time is a time for cleaning the sample injection needle; The delay volume is a sum of a space volume inside the gradient proportioning valve and the mobile phase delivery assembly and a volume inside all pipelines between the gradient proportioning valve and the sample buffer assembly.

3. The gradient elution control method according to claim 1, characterized by, The switching assembly is a six-way valve, the six-way valve comprises a first interface, a second interface, a third interface, a fourth interface, a fifth interface, a sixth interface and a sample buffer assembly; wherein the sample buffer assembly is in communication between the first interface and the fourth interface; The sample injection passage is a passage composed of the third interface, the fourth interface, the sample buffer assembly, the first interface and the second interface. The liquid phase passage is a passage formed by the fifth interface, the fourth interface, the sample buffer assembly, the first interface and the sixth interface; The flow phase supply assembly, the gradient proportion mixing valve and the flow phase delivery assembly are sequentially communicated and communicated to the fifth interface of the six-way valve; The injection device is communicated with the third interface of the six-way valve; The sixth interface of the six-way valve, the chromatographic column and the detector are sequentially communicated.

4. The gradient elution control method of claim 1, wherein, The flow phase supply assembly comprises at least two independent solvent bottles and a degassing machine; The degassing machine comprises at least two groups of degassing interfaces, each group of the degassing interfaces is communicated with one of the solvent bottles and transmits the liquid phase in the corresponding solvent bottle to the gradient proportion mixing valve.

5. The gradient elution control method of claim 1, wherein, The flow phase delivery assembly comprises a first delivery pump, a second delivery pump and a mixer; A one-way valve is respectively installed on the pipeline before the first delivery pump and the second delivery pump; The inlet of the mixer is communicated with the outlet of the second delivery pump; The outlet of the mixer is communicated with the inlet of the liquid phase passage.

6. The gradient elution control method of claim 1, wherein, The injection device comprises a syringe, a sample bottle and an injection needle; The syringe is used to control the injection needle to suck the sample from the sample bottle and push the sample into the injection passage.

7. The gradient elution control method according to claim 3, wherein, The system further comprises a cleaning assembly; The cleaning assembly comprises a cleaning bottle for placing cleaning liquid; When the injection device is cleaned, the second interface and the third interface are communicated.

8. The gradient elution control method according to claim 3, wherein, The control of the injection passage being conducted comprises: Controlling the first interface and the second interface of the switching assembly to be communicated, the third interface and the fourth interface to be communicated; The control of the liquid phase passage being communicated with the remaining two interfaces except the two interfaces connected with the sample buffer assembly comprises: Controlling the first interface and the sixth interface of the switching assembly to be disconnected, the fourth interface and the fifth interface to be disconnected and the fifth interface and the sixth interface to be communicated.

9. The gradient elution control method according to claim 3, wherein, The control of the injection passage being disconnected and the liquid phase passage being conducted comprises: Controlling the first interface and the second interface of the switching assembly to be disconnected, the third interface and the fourth interface to be disconnected; And controlling the first interface and the sixth interface to be communicated, the fourth interface and the fifth interface to be communicated and the fifth interface and the sixth interface to be disconnected.

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