Liquid suction state judgment method and equipment, storage medium and pipetting system

Abstract

The invention relates to the technical field of pipetting, and discloses a liquid suction state judgment method which comprises the following steps: controlling a pipettor to descend to extend into sample liquid; obtaining the internal air pressure of the pipettor before liquid suction to obtain a first internal air pressure value; controlling the pipettor to suck the sample liquid, acquiring the internal air pressure of the pipettor at intervals of preset liquid suction amount in the liquid suction process of the pipettor, and sequentially obtaining a plurality of second internal air pressure values; obtaining the internal air pressure of the pipettor after liquid suction to obtain a third internal air pressure value; the difference value between every two adjacent second internal air pressure values is calculated, and a plurality of first pressure differences are obtained in sequence; calculating a difference value between the first internal air pressure value and the third internal air pressure value to obtain a second pressure difference; if a continuous first preset number of first pressure differences in the multiple first pressure differences are larger than the first air pressure threshold value, and the second pressure difference is larger than the second air pressure threshold value, it is determined that the pipettor is sucked and blocked. By means of the mode, the situation that pipetting is inaccurate due to missed judgment of suction blockage of the pipettor is avoided.

Description

Technical Field

[0001] This application relates to the field of pipetting technology, specifically to a method, device, storage medium, and pipetting system for determining the aspiration status. Background Technology

[0002] Automated pipetting systems assess the aspiration status of the pipette during the pipetting process, enabling timely clearing of blockages upon detection, which is a crucial means of ensuring pipetting accuracy.

[0003] Currently, pipette blockage is typically determined by checking if the pressure difference before and after sample aspiration reaches a threshold, allowing for real-time monitoring of blockage during pipetting. However, when the sample viscosity reaches a certain level, it can slightly clog the pipette tip, preventing the pipette from aspirating a portion of the sample. While the pressure difference before and after aspiration is greater than the normal pressure difference before and after aspiration, it is still below the aforementioned blockage threshold. This means that existing methods may miss blockage caused by excessively high sample viscosity, leading to inaccurate pipetting. Summary of the Invention

[0004] In view of the above problems, this application provides a method, device, storage medium and pipetting system for judging the liquid aspiration status, so as to avoid inaccurate pipetting caused by pipetting blockage due to missed judgment.

[0005] According to one aspect of the embodiments of this application, a method for determining the liquid aspiration state is provided. The method includes: controlling a pipette to descend to insert into the sample liquid; acquiring the internal pressure of the pipette before aspirating the sample liquid to obtain a first internal pressure value; controlling the pipette to aspirate the sample liquid, and acquiring the internal pressure of the pipette at preset aspiration intervals during the aspiration process to obtain a plurality of second internal pressure values; acquiring the internal pressure of the pipette after aspirating the sample liquid to obtain a third internal pressure value; calculating the difference between two adjacent second internal pressure values ​​to obtain a plurality of first pressure differences; calculating the difference between the first internal pressure value and the third internal pressure value to obtain a second pressure difference; if there is a first preset number of consecutive first pressure differences greater than a first pressure threshold, and a second pressure difference greater than a second pressure threshold, then the liquid aspiration state of the pipette is determined to be aspiration blockage.

[0006] In one alternative approach, if there is no consecutive first preset number of first pressure differences greater than a first pressure threshold among a plurality of first pressure differences, and / or the second pressure difference is less than or equal to a second pressure threshold, then the pipette's aspiration state is determined to be non-blocked.

[0007] In one alternative approach, after determining that the pipette is blocked, the method further includes: controlling the pipette to eject the aspirated sample liquid; generating a first alarm message to indicate that the pipette is blocked.

[0008] In one optional embodiment, the method further includes: calculating the pressure change slope of the pipette based on two adjacent second internal pressure values ​​among a plurality of second internal pressure values, to obtain a plurality of pressure change slopes; calculating the pressure change slope difference of the pipette based on two adjacent pressure change slopes among the plurality of pressure change slopes, to obtain a plurality of slope differences; if there is a slope difference among the plurality of slope differences that is greater than a preset slope threshold, and the second pressure difference is less than a third pressure threshold, then the pipette's aspiration state is determined to be empty; if there is no slope difference among the plurality of slope differences that is greater than a preset slope threshold, and / or, the second pressure difference is greater than or equal to the third pressure threshold, then the pipette's aspiration state is determined to be not empty.

[0009] In one alternative approach, after determining that the pipette's aspiration status is empty, the method further includes: controlling the pipette to push out the aspirated sample liquid; controlling the pipette to rise above the sample liquid surface and then proceeding to the step of controlling the pipette to descend into the sample liquid; and generating a second alarm message when the pipette's aspiration status is determined to be empty again, the second alarm message being used to indicate that the pipette has emptied.

[0010] In one alternative approach, controlling the pipette to descend into the sample solution further includes: acquiring the internal pressure of the pipette above the sample solution to obtain a fourth internal pressure value; controlling the pipette to descend at a preset speed; controlling the pipette to perform a blowing operation during the descent; acquiring the internal pressure of the pipette in real time during the blowing operation to obtain a fifth internal pressure value; calculating the difference between the fifth internal pressure value and the fourth internal pressure value to obtain a third pressure difference; and controlling the pipette to stop performing the blowing operation when the third pressure difference is greater than the fourth pressure threshold for a second consecutive preset number of times, and controlling the pipette to descend a preset distance to enter the sample solution.

[0011] In one alternative embodiment, the pipette includes a plunger; controlling the pipette to perform a blowing operation during the descent of the pipette further includes: controlling the plunger to move along a first direction during the descent of the pipette to drive the pipette to perform the blowing operation; controlling the pipette to stop performing the blowing operation when a second preset number of third pressure differences are greater than a fourth pressure threshold, further including: controlling the plunger to stop moving when a second preset number of third pressure differences are greater than the fourth pressure threshold, so that the pipette stops performing the blowing operation; controlling the pipette to aspirate sample liquid further includes: controlling the plunger to move in the opposite direction of the first direction to drive the pipette to aspirate sample liquid.

[0012] According to another aspect of the embodiments of this application, a liquid aspiration state determination device is provided, including a memory, a processor, and a computer program stored in the memory. The processor executes the computer program to implement the liquid aspiration state determination method provided in any of the above embodiments.

[0013] According to another aspect of the embodiments of this application, a pipetting system is provided, which includes a pipette and the aspiration state judgment device provided in the above embodiments. The pipette is provided with a pressure sensor, which is communicatively connected to the aspiration state judgment device. The aspiration state judgment device is used to control the pipette to descend or rise and to control the pipette to aspirate sample liquid. The pressure sensor is used to acquire the internal air pressure of the pipette and send the internal air pressure of the pipette to the aspiration state judgment device.

[0014] According to another aspect of the embodiments of this application, a computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the liquid aspiration state determination method provided in any of the above embodiments.

[0015] This embodiment of the application obtains multiple second internal pressure values ​​of the pipette at preset intervals during the process of aspirating sample liquid. Then, by sequentially calculating the difference between two adjacent second internal pressure values, multiple first pressure differences are obtained, allowing determination of the internal pressure change of the pipette for each preset volume of sample liquid aspirated. Furthermore, by calculating the second pressure difference between the first internal pressure before aspirating sample liquid and the third internal pressure after aspirating sample liquid, the internal pressure change of the pipette before and after aspirating sample liquid can be determined. Thus, when a first preset number of consecutive first pressure differences exceed a first pressure threshold, it can be determined that the internal pressure change of the pipette exceeds its internal pressure change during normal aspiration during the aspiration of a certain volume of sample liquid; when the second pressure difference before and after aspirating sample liquid is greater than the first pressure threshold before and after normal aspiration, it can be determined that the internal pressure change of the pipette before and after aspirating sample liquid is greater than its internal pressure change before and after normal aspiration. Therefore, even if the sample solution viscosity is too high and causes the pipette to partially block, it can accurately determine that the pipette is blocked, avoiding missed detection and ensuring accurate pipetting.

[0016] The above description is merely an overview of the technical solutions of the embodiments of this application. In order to better understand the technical means of the embodiments of this application and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of this application more obvious and understandable, specific implementation methods of this application are described below. Attached Figure Description

[0017] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic diagram of the pipetting system provided in an embodiment of this application is shown; Figure 2 A schematic diagram of the controller provided in an embodiment of this application is shown; Figure 3 A flowchart illustrating the liquid aspiration state determination method provided in an embodiment of this application is shown; Figure 4 It shows Figure 3 A flowchart illustrating the process up to step 150; Figure 5 It shows Figure 3 A flowchart illustrating the sub-steps of step 110; Figure 6 A schematic diagram of the liquid aspiration state determination device provided in an embodiment of this application is shown. Detailed Implementation

[0018] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. Although exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the embodiments set forth herein.

[0019] With the rapid development of the medical testing field, automated pipetting systems have become crucial for improving experimental efficiency and accuracy. During the operation of automated pipetting systems, clogging is a common problem affecting pipetting accuracy. This is because when clots are present in the sample solution, the pipette tip may become blocked, preventing the pipette from drawing sufficient sample and thus reducing accuracy. Therefore, assessing the pipette's aspiration status during pipetting and taking timely declogging measures upon detection is an important means of ensuring pipetting accuracy.

[0020] During pipetting, the air pressure inside the pipette first decreases to be lower than the air pressure outside the pipette, creating a negative pressure inside and outside the pipette sufficient to draw a sufficient amount of sample solution. Under this negative pressure, the sample solution is pushed into the pipette tip, i.e., the pipette draws the sample solution. Then, as the pipette moves to the sample analysis device, it pushes the drawn sample solution into the sample analysis device, thus completing one pipetting operation.

[0021] When a pipette aspirates a sufficient amount of sample solution, the pressure change inside the pipette equals the equivalent pressure required to balance the gravity, surface tension, inertial force, and adhesive force of the sufficient sample solution. When the pipette becomes clogged, because only a small amount of liquid is aspirated or even none, the pressure change inside the pipette is much greater than the aforementioned equivalent pressure. Utilizing this difference, existing technologies typically determine whether the pipette is clogged by judging whether the pressure difference before and after aspirating the sample solution reaches a threshold, thus enabling real-time detection of pipette blockage during the pipetting process.

[0022] However, when the viscosity of the sample solution reaches a certain level, the surface tension and adhesion of the sample solution increase, causing slight blockage of the pipette tip, resulting in partial blockage. This means the negative pressure created inside the pipette cannot aspirate a sufficient amount of sample solution; for example, only 50% to 70% of the sample solution may be aspirated. Although the pressure difference before and after aspirating the sample solution is greater than the normal pressure difference before and after aspiration, it is still less than the threshold for determining blockage. Therefore, judging whether the pipette is blocked by judging the pressure difference before and after aspiration cannot detect blockage caused by excessively high sample viscosity, leading to missed detections and inaccurate pipetting.

[0023] The applicant's research revealed that when a pipette is used normally for aspiration, the internal pressure change is essentially the same for each volume of sample aspirated. However, when a pipette becomes clogged, the internal pressure change for the same volume of sample aspirated is greater than that during normal aspiration. Furthermore, the internal pressure change before and after aspiration is greater when the pipette is clogged than the pressure change before and after normal aspiration.

[0024] Based on this, this application acquires the internal pressure value of the pipette each time a preset volume of sample liquid is drawn, and calculates the difference between two adjacent internal pressure values ​​sequentially to determine the short-term internal pressure change value of the pipette after drawing a certain volume. Then, each short-term internal pressure change value is compared with each short-term internal pressure change value corresponding to normal aspiration, and the internal pressure change value before and after sample liquid aspiration is compared with the internal pressure change value before and after normal aspiration. When multiple consecutive short-term internal pressure change values ​​are greater than each short-term internal pressure change value corresponding to normal aspiration, and the internal pressure change value before and after sample liquid aspiration is greater than the internal pressure change value before and after normal aspiration, it is determined that the pipette has become clogged. Through this method, even if the sample liquid viscosity is too high, causing partial blockage of the pipette, it can be accurately determined that the pipette has become clogged, avoiding missed detections and ensuring accurate pipetting.

[0025] The liquid aspiration state determination method provided in this application embodiment is applied to a pipetting system, such as... Figure 1As shown, the pipetting system 1 includes a pipette 10 and a liquid aspiration status determination device 20. The liquid aspiration status determination method is performed by the liquid aspiration status determination device 20. A pressure sensor 11 is installed on the pipette 10, and the pressure sensor 11 is communicatively connected to the liquid aspiration status determination device 20. The liquid aspiration status determination device 20 is used to control the pipette 10 to descend or rise and to control the pipette 10 to aspirate sample liquid. The pressure sensor 11 is used to acquire the internal air pressure of the pipette 10 and send the internal air pressure of the pipette 10 to the liquid aspiration status determination device 20.

[0026] like Figure 1 As shown, a plunger 12 is installed inside the plunger cylinder of the pipette 10. The plunger 12 is connected to the motor of the pipette 10. By controlling the rotation of the motor, the plunger 12 can be moved up and down within the plunger cylinder of the pipette 10, thereby changing the air pressure inside the plunger cylinder. A pressure sensor 11, which can be a pneumatic pressure sensor, is used to detect the air pressure inside the plunger cylinder of the pipette 10, i.e., the internal air pressure of the pipette 10. A pipette tip 13 is installed at the lower end of the plunger cylinder of the pipette 10 for aspirating sample liquid. The orifice diameter of the pipette tip can be set to 1 mm. A robotic arm can also be installed at the upper end of the pipette 10. By controlling the vertical movement of the robotic arm, the pipette 10 can be lowered or raised.

[0027] The liquid aspiration status determination device 20 can be a computer, server, tablet computer, or controller. Taking a controller as an example, for instance... Figure 2 As shown, the controller can be an STM32 main control module. Through the RS-232 standard interface, the computer can burn the program corresponding to the liquid aspiration state judgment method of this application embodiment into the STM32 main control module, and the STM32 main control module executes the program to implement the liquid aspiration state judgment method of this application embodiment.

[0028] Specifically, the STM32 main control module can control the rotation of the motor of the pipette 10 through the TMC5160 controller, thereby controlling the plunger 12 to move up and down within the plunger cylinder. The STM32 main control module can also control the movement of the robotic arm in the vertical direction, thereby controlling the pipette 10 to rise or fall.

[0029] Specifically, when the liquid aspiration status judgment device 20 controls the pipette 10 to move until its pipette tip 13 is above the sample liquid surface, the plunger cylinder and pipette tip 13 are connected to the external atmospheric environment, and the air pressure inside the plunger cylinder is equal to the atmospheric pressure. When the plunger 12 moves along the plunger cylinder as shown in the image... Figure 1When the pipette tip 13 moves in the direction indicated by arrow X (i.e., vertically downward), it blows gas outward. At this time, the air pressure inside the plunger cylinder remains equal to atmospheric pressure. After the pipette tip 13 of the pipette 10 is inserted into the sample solution, when the plunger 12 moves in the plunger cylinder in the direction indicated by arrow X, the gas cannot be blown outward, causing the air pressure inside the plunger cylinder to increase with the movement of the plunger 12 until the plunger 12 stops moving, at which point the air pressure inside the plunger cylinder no longer changes. After this, when the plunger 12 moves in the opposite direction indicated by arrow X (i.e., vertically upward), the air pressure inside the plunger cylinder gradually decreases with the movement of the plunger 12. When the air pressure inside the plunger cylinder decreases to less than atmospheric pressure, a negative pressure is formed inside and outside the pipette 10. Under the action of the negative pressure, the sample solution is pushed into the pipette tip 13, that is, the pipette 10 aspirates the sample solution. In this way, the aspiration status judgment device 20 can control the pipette 10 to aspirate a preset volume of sample solution by controlling the stroke of the plunger 12.

[0030] Figure 3 A flowchart of the liquid aspiration state determination method provided in an embodiment of this application is shown. The method consists of... Figure 1 The liquid aspiration status judgment device 20 in the pipetting system 1 shown is executed. For example... Figure 3 As shown, the method includes the following steps: Step 110: Control the pipette to descend until it is inserted into the sample solution.

[0031] First, the pipette is moved above the sample tube containing the sample solution using a robotic arm. Then, the pipette descends at a constant speed using the robotic arm until the pipette tip contacts the sample solution. During the descent, the plunger can be controlled to move along... Figure 1 Move the pipette in the direction indicated by the middle arrow X to expel gas from the pipette for liquid level detection. Before the tip contacts the sample liquid, the internal pressure of the pipette is always equal to atmospheric pressure. Once the tip contacts the sample liquid, it is blocked by the liquid, preventing the pipette from expelling gas and causing the internal pressure to gradually increase. When the pipette detects the liquid level, stop moving the plunger, thus stopping the expulsion of gas. At this point, the internal pressure of the pipette stops increasing and remains stable. Continue to lower the pipette until the tip is below the liquid surface, for example, 2 mm below the surface. This ensures that the pipette can aspirate a sufficient amount of sample liquid.

[0032] Step 120: Obtain the internal air pressure of the pipette before it draws the sample liquid, and obtain the first internal air pressure value.

[0033] Before the pipette draws the sample liquid, the first internal air pressure value 'a' of the pipette can be obtained by a pressure sensor to determine the internal air pressure of the pipette before it draws the sample liquid.

[0034] Step 130: Control the pipette to draw sample liquid, and during the process of the pipette drawing sample liquid, obtain the internal air pressure of the pipette at preset intervals of liquid volume, and obtain multiple second internal air pressure values ​​in sequence.

[0035] Can control the plunger along Figure 1 Move the pipette 5 mm in the opposite direction of the X-shaped arrow to aspirate 80 μL of sample solution.

[0036] The preset aspiration volume can be set to 10 μL. Specifically, the pressure sensor can be controlled to detect the second internal air pressure value of the pipette every time 10 μL of sample liquid is aspirated, so that the second internal air pressure value of the pipette can be detected every 10 μL.

[0037] Under normal circumstances, when a pipette aspirates 80 μL, the internal pressure change is -0.375 kPa for every 10 μL aspirated. When the sample solution has a higher viscosity, a greater negative pressure is required to overcome the increased surface tension and adhesion of the sample solution for every 10 μL aspirated. This means that the internal pressure change is greater than -0.375 kPa, resulting in a pipette ultimately not being able to aspirate 80 μL of sample solution with the same plunger stroke; it may only be able to aspirate 50 μL or 60 μL of sample solution.

[0038] For example, when the pipette aspirates a total of 60 μL of sample liquid, the second internal pressure values ​​corresponding to aspirated volumes of 10 μL, 20 μL, 30 μL, 40 μL, 50 μL, and 60 μL are n1, n2, n3, n4, n5, and n6, respectively. These pressure values ​​are detected and stored for later use.

[0039] Step 140: Obtain the internal air pressure after the pipette aspirates the sample liquid, and obtain the third internal air pressure value.

[0040] After the pipette aspirates the sample solution (i.e., after aspiration is complete), the third internal pressure value b of the pipette is obtained again to determine the internal pressure of the pipette after aspirating the sample solution.

[0041] Step 150: Calculate the difference between two adjacent second internal air pressure values ​​to obtain multiple first pressure differences in sequence.

[0042] Specifically, first, calculate the pressure change inside the pipette during the 0-10 μL aspiration phase: n1a = n1 - a; then calculate the pressure change inside the pipette during the 10-20 μL aspiration phase: n21 = n2 - n1; next, calculate the pressure change inside the pipette during the 30-20 μL aspiration phase: n32 = n3 - n2... In this way, six first pressure differences can be calculated respectively: n1a, n21, n32, n43, n54, n65.

[0043] Step 160: Calculate the difference between the first internal air pressure value and the third internal air pressure value to obtain the second pressure difference.

[0044] The second pressure difference characterizes the pressure change before and after the pipette aspirates the sample solution. Specifically, the second pressure difference ba = the third internal pressure value b - the first internal pressure value a.

[0045] Step 170: If a first preset number of first pressure differences are greater than a first gas pressure threshold and a second pressure difference is greater than a second gas pressure threshold, then the pipette's suction state is determined to be suction blockage.

[0046] The first preset quantity can be set to 5. The preset aspiration volume can be set according to the total aspiration volume of the pipette. When the total aspiration volume of the pipette is small, the preset aspiration volume can be reduced so that the total number of preset aspiration volume intervals is greater than the first preset quantity, ensuring that the number of calculated first pressure differences is greater than the first preset quantity, thus guaranteeing the accuracy of aspiration status judgment. When the total aspiration volume of the pipette is large, the preset aspiration volume can be increased, and the total number of preset aspiration volume intervals can be reduced. While ensuring that the number of calculated first pressure differences is greater than the first preset quantity, the number of first pressure difference judgments can be reduced, improving the efficiency of aspiration status judgment.

[0047] In this embodiment, the first pressure threshold is determined based on the pressure change calculated at each preset aspiration volume (e.g., 10 μL) during normal pipetting; the second pressure threshold is determined based on the pressure change before and after normal pipetting. The first pressure threshold can be set as the pressure change calculated at each preset aspiration volume during normal pipetting multiplied by a first coefficient greater than 1. The second pressure threshold can be set as the pressure change before and after normal pipetting multiplied by a second coefficient greater than 1. Considering that the pressure change before and after normal pipetting corresponds to a larger aspiration volume, the second coefficient can be greater than the first coefficient.

[0048] Specifically, the first step is to calculate the data for normal pipette aspiration. Specifically, when the normal aspiration volume is 80 μL, the internal pressure before aspiration is 'c'. The internal pressure values ​​for aspiration volumes of 10 μL, 20 μL, 30 μL, 40 μL, 50 μL, 60 μL, 70 μL, and 80 μL are m1, m2, m3, m4, m5, m6, m7, and m8, respectively. The internal pressure value after aspiration is 'd'.

[0049] Then, calculate the internal gas pressure change of the pipette during the 0-10 μL aspiration phase: m1c = m1 - c; calculate the internal gas pressure change of the pipette during the 10-20 μL aspiration phase: m21 = m2 - m1; calculate the internal gas pressure change of the pipette during the 30-20 μL aspiration phase: m32 = m3 - m2... Thus, we can calculate eight gas pressure changes during normal aspiration: m1c, m21, m32, m43, m54, m65, m76, m87. The internal gas pressure change dc of the pipette before and after normal aspiration is: dc = dc.

[0050] Thus, during normal pipette aspiration, the first gas pressure threshold M1 corresponding to the aspiration volume of 0-10μL can be set to 1.15m1c, the first gas pressure threshold M2 corresponding to the aspiration volume of 10μL-20μL can be set to 1.15m21, the first gas pressure threshold M3 corresponding to the aspiration volume of 10μL-20μL can be set to 1.15m32, and so on, resulting in 8 first gas pressure thresholds: M1, M2, M3, M4, M5, M6, M7, and M8; the second gas pressure threshold B can be set to 1.25dc.

[0051] In determining whether a pipette is clogged, the following steps are performed sequentially: first pressure difference n1a is compared with the first gas pressure threshold M1, first pressure difference n21 with the first gas pressure threshold M2, first pressure difference n32 with the first gas pressure threshold M3, first pressure difference n43 with the first gas pressure threshold M4, first pressure difference n54 with the first gas pressure threshold M5, and first pressure difference n65 with the first gas pressure threshold M6. If five consecutive first pressure differences are greater than their corresponding first gas pressure thresholds (e.g., first pressure differences n21, n32, n43, n54, and n65 are all greater than their corresponding first gas pressure thresholds M2, M3, M4, M5, and M6), it indicates that for every 10 μL aspirated, the internal gas pressure change of the pipette is greater than the internal gas pressure change during normal aspiration, and the internal gas pressure change of the pipette for five consecutive 10 μL aspirations exceeds 15% of the internal gas pressure change during normal aspiration. In this case, if the second pressure difference ba is greater than the second air pressure threshold B, it indicates that the internal air pressure change of the pipette before and after this aspiration is greater than the internal air pressure change of the pipette before and after normal aspiration, and the internal air pressure change of the pipette before and after aspirating the sample exceeds 25% of the internal air pressure change before and after normal aspiration. At this point, combining the two comparison results, it can be determined that the pipette is clogged.

[0052] In some embodiments, if there is no consecutive first preset number of first pressure differences greater than a first gas pressure threshold among a plurality of first pressure differences, and / or the second pressure difference is less than or equal to a second gas pressure threshold, then the pipette's aspiration state is determined to be non-blocked.

[0053] Specifically, if only one, two, three, or four of the first pressure differences n1a, n21, n32, n43, n54, and n65 are greater than their corresponding first gas pressure thresholds (e.g., only the first pressure difference n32 is greater than the first gas pressure threshold M3), or all the first pressure differences are less than or equal to their corresponding first gas pressure thresholds, or although five of the first pressure differences are greater than their corresponding first gas pressure thresholds but these five pressure differences are discontinuous, it indicates that the internal gas pressure change of the pipette did not exceed 15% of the normal internal gas pressure change during five consecutive 10μL sample aspirations, and the pipette can be determined to be unblocked. If five of the multiple first pressure differences are greater than their corresponding first gas pressure thresholds, but the second pressure difference ba is less than or equal to the second gas pressure threshold B, it indicates that the internal gas pressure change of the pipette before and after sample aspiration does not exceed 25% of the normal internal gas pressure change before and after pipette aspiration, and the pipette can also be determined to be unblocked.

[0054] This embodiment of the application obtains multiple second internal pressure values ​​of the pipette at preset intervals during the process of aspirating sample liquid. Then, by sequentially calculating the difference between two adjacent second internal pressure values, multiple first pressure differences are obtained, allowing determination of the internal pressure change of the pipette for each preset volume of sample liquid aspirated. Furthermore, by calculating the second pressure difference between the first internal pressure before aspirating sample liquid and the third internal pressure after aspirating sample liquid, the internal pressure change of the pipette before and after aspirating sample liquid can be determined. Thus, when a first preset number of consecutive first pressure differences exceed a first pressure threshold, it can be determined that the internal pressure change of the pipette exceeds its internal pressure change during normal aspiration during the aspiration of a certain volume of sample liquid; when the second pressure difference before and after aspirating sample liquid is greater than the first pressure threshold before and after normal aspiration, it can be determined that the internal pressure change of the pipette before and after aspirating sample liquid is greater than its internal pressure change before and after normal aspiration. Therefore, even if the sample solution viscosity is too high and causes the pipette to partially block, it can accurately determine that the pipette is blocked, avoiding missed detection and ensuring accurate pipetting.

[0055] In some embodiments, after determining that the pipette's suction state is blocked, the plunger can be controlled along... Figure 1 Move the pipette in the direction indicated by the middle arrow X to expel the aspirated sample solution and clear any blockage in the pipette tip. After this, a first alarm message is generated to indicate that the pipette has become clogged. For example, the first alarm message can activate a buzzer or warning light to notify the operator that the pipette has become clogged. The operator can then check the sample solution and pipette tip to ensure that subsequent pipetting operations proceed normally.

[0056] In existing technologies, the determination of whether a pipette has emptied is generally based on the internal pressure change before and after aspiration being less than a pressure threshold. This is because, under normal circumstances, when a pipette empties, its internal pressure gradually decreases to equal atmospheric pressure. However, when a pipette picks up an air bubble, the bubble may form a liquid film inside the tip. In this case, as the pipette aspirates sample liquid, the liquid film continues to move upwards within the tip as the internal pressure decreases, causing the internal pressure to gradually decrease to below atmospheric pressure. When the volume of sample liquid to be aspirated is small, the internal pressure change before and after normal aspiration may be small. In this case, the pressure threshold for determining whether the pipette has emptied may also be small. The formation of the liquid film may cause the pressure change before and after aspiration to exceed this pressure threshold, making it impossible to determine whether the pipette has emptied, leading to inaccurate pipetting.

[0057] To improve the accuracy of pipette aspiration detection, this application further provides an implementation method. Optionally, please refer to... Figure 4 , Figure 4 It shows Figure 3 A flowchart following step 140 is shown below. Figure 4 As shown, the following steps are included after step 140: Step 141: Calculate the pressure change slope of the pipette based on two adjacent second internal pressure values ​​among multiple second internal pressure values, and obtain multiple pressure change slopes.

[0058] Specifically, when the volume of liquid aspirated is 10 μL, the slope of the gas pressure change of the pipette is k1: k1 = n1 / 10; when the volume of liquid aspirated is 20 μL, the slope of the gas pressure change of the pipette is k2: k2 = n21 / 10; when the volume of liquid aspirated is 30 μL, the slope of the gas pressure change of the pipette is k3: k3 = n32 / 10... From this, we can obtain 6 gas pressure change slopes k1, k2, k3, k4, k5, and k6 respectively.

[0059] Step 142: Calculate the difference in pressure change slope of the pipette based on the slope of two adjacent pressure changes among multiple pressure change slopes, and obtain multiple slope difference values.

[0060] First, calculate the difference between the slope of the air pressure change k1 and the slope of the air pressure change k2 to obtain the first slope difference K1: K1=k1-k2. Then calculate the difference between the slope of the air pressure change k2 and the slope of the air pressure change k3: K2=k2-k3... From this, we can calculate five slope differences in sequence: K1, K2, K3, K4, K5.

[0061] Step 143: If there is a slope difference greater than the preset slope threshold among the multiple slope differences, and the second pressure difference is less than the third gas pressure threshold, then the pipette's aspiration state is determined to be empty.

[0062] The third pressure threshold C can be set to 2 kPa. The preset slope threshold can be set as the slope difference calculated for each preset volume of liquid aspirated during normal aspiration by the pipette, multiplied by a third coefficient greater than 1.

[0063] Assuming a preset slope threshold of D, if at least one of the slope differences K1, K2, K3, K4, and K5 is greater than the preset slope threshold D (e.g., K2 > D), it indicates a jump in the pressure change slope k3, meaning the internal pressure of the pipette jumps during the 20-30 μL sample volume aspirated. In this case, if the second pressure difference ba is less than the third pressure threshold C, it indicates that the internal pressure change before and after aspiration is less than the internal pressure change during liquid level detection. Based on these two comparisons, it can be determined that the pipette has experienced cavitation.

[0064] Step 144: If there is no slope difference greater than the preset slope threshold among the multiple slope differences, and / or the second pressure difference is greater than or equal to the third gas pressure threshold, then the pipette's aspiration state is determined to be not empty.

[0065] If none of the slope differences K1, K2, K3, K4, and K5 are greater than the preset slope threshold D, meaning all slope differences are less than or equal to the preset slope threshold D, it indicates that the internal pressure of the pipette did not change during the pipette's sample aspiration process, thus confirming that the pipette did not aspirate empty. When the second pressure difference ba is greater than or equal to the third pressure threshold C, it indicates that the change in internal pressure before and after aspiration is greater than the change in internal pressure during the pipette's surface probing process; in this case, it can also be confirmed that the pipette did not aspirate empty.

[0066] By determining whether the internal pressure of the pipette changes abruptly during sample aspiration, and whether the pressure change before and after aspirating the sample is less than the internal pressure change caused by the pipette probing the liquid surface, it is possible to accurately identify pipette cavitation caused by air bubbles forming a liquid film. This avoids missed detections of pipette cavitation, making the determination of pipette cavitation more accurate and ensuring the accuracy of pipetting.

[0067] In some embodiments, please continue reading Figure 4 After confirming that the pipette has been emptied, that is, after step 142, the following steps are also included: Step 145: Control the pipette to eject the aspirated sample solution.

[0068] Step 146: Control the pipette to rise above the surface of the sample solution and proceed to step 110.

[0069] Step 147: Once the pipette's aspiration status is confirmed to be empty again, a second alarm message is generated. The second alarm message is used to indicate that the pipette has emptied.

[0070] Specifically, the plunger can be controlled along... Figure 1 The pipette moves in the direction indicated by the middle arrow X to push out the aspirated sample liquid (i.e., the liquid film) and clear the liquid film from the tip. After this, the pipette can be raised at a constant speed using a robotic arm, raising the tip above the sample liquid surface for tip replacement. After tip replacement, the pipette can be lowered again until the tip is submerged in the sample liquid for re-aspiration. When the pipette is again confirmed to be empty, a second alarm message is generated to alert the operator that the pipette has run out of liquid. The method by which the second alarm message alerts the operator to empty pipette is the same as the method by which the first alarm message alerts the operator to pipette blockage, and will not be described again here.

[0071] In response to the second alarm message, the operator can check the sample solution to remove air bubbles and ensure that the pipette can draw up the sample solution normally in the future.

[0072] To improve the accuracy of pipetting, this application further provides an implementation method. Optionally, please refer to [link to implementation details]. Figure 5 , Figure 5 It shows Figure 3 The flowchart of the sub-steps in step 110 is shown in the figure. Step 110 includes the following steps: Step 111: Obtain the internal air pressure of the pipette above the sample liquid to obtain the fourth internal air pressure value.

[0073] After the pipette is moved above the sample solution by the robotic arm, the fourth internal pressure value of the pipette is first obtained to determine the initial value of the pressure sensor. At this time, the internal pressure of the pipette is equal to the atmospheric pressure, that is, the fourth internal pressure value is equal to the atmospheric pressure. Therefore, the initial value of the pressure sensor is generally 0.

[0074] Step 112: Control the pipette to descend at a preset speed.

[0075] For example, a pipette can be controlled by a robotic arm to descend at a speed of 5 mm / s.

[0076] Step 113: Control the pipette to perform the air blowing operation during the pipette descent.

[0077] During the descent of the pipette, a motor can be driven to rotate, thereby controlling the plunger of the pipette to move in the first direction, i.e., the direction indicated by arrow X, so as to drive the pipette to perform the blowing operation, so that the pipette can continuously blow gas outward.

[0078] Step 114: During the blowing operation of the pipette, the internal air pressure of the pipette is acquired in real time to obtain the fifth internal air pressure value.

[0079] The fifth internal pressure value of the pipette is acquired in real time as it descends at a constant speed and continuously expels gas. Before the pipette tip contacts the sample liquid, the fifth internal pressure value of the pipette remains equal to atmospheric pressure, i.e., it remains 0. The fifth internal pressure value increases when the pipette tip contacts the sample liquid.

[0080] Step 115: Calculate the difference between the fifth internal air pressure value and the fourth internal air pressure value to obtain the third pressure difference.

[0081] Before the pipette tip contacts the sample solution surface, the fifth internal pressure value is equal to the fourth internal pressure value, meaning the third pressure difference is zero. When the pipette tip contacts the sample solution surface, the fifth internal pressure value increases, causing the third pressure difference to increase.

[0082] Step 116: When the third pressure difference is greater than the fourth gas pressure threshold for the second consecutive preset number of times, control the pipette to stop performing the blowing operation and control the pipette to descend a preset distance to insert into the sample solution.

[0083] The second preset quantity can be set to 3. The fourth air pressure threshold can be set to 2 kPa.

[0084] In some cases, when the pipette tip touches and pierces the air bubble, the gas expelled by the pipette is located inside the bubble. This can increase the internal pressure of the pipette, leading to an increase in the fifth internal pressure value and consequently, an increase in the third pressure difference. In this situation, the calculated third pressure difference may exceed the fourth pressure threshold. If it is directly assumed that the pipette has detected the sample liquid surface, the pipette tip may remain above the sample liquid surface even after the pipette descends further, or may be slightly submerged in the sample liquid, preventing the pipette from drawing a sufficient amount of sample liquid.

[0085] To avoid the above situation, when the calculated third pressure difference is greater than the fourth gas pressure threshold, the pipette is controlled to continue performing the blowing operation so that the pipette can continue to blow out gas. In this way, even if the pipette detects a bubble, the bubble will be burst by the gas subsequently blown out by the pipette, so that the internal gas pressure of the pipette is equal to atmospheric pressure again, that is, the fifth internal gas pressure value is equal to the fourth internal gas pressure value again, thereby making the third pressure difference less than the fourth gas pressure threshold.

[0086] In this situation, by determining whether the calculated third pressure difference is consistently greater than the fourth gas pressure threshold, the detection of air bubbles by the pipette can be mistaken for the pipette detecting a liquid surface. For example, when three consecutive calculated third pressure differences are greater than the fourth gas pressure threshold, it indicates that the pipette tip has detected a liquid surface. At this point, the motor can be stopped, thereby stopping the plunger's movement and halting the pipette's blowing operation, thus stopping the pipette from blowing gas outwards. Next, the pipette can be lowered another 2mm by the robotic arm, allowing the tip to enter the sample solution and ensuring that the pipette can aspirate a sufficient amount of sample solution. After this, the motor is rotated again, thereby controlling the plunger to move in the opposite direction of the first direction, i.e., the opposite direction indicated by arrow X, which drives the pipette to begin aspirating the sample solution.

[0087] By using the above method, misjudgments caused by air pressure fluctuations due to air bubbles can be avoided, making the liquid level detection results more reliable. This ensures that the pipette descends a certain distance to insert into the sample liquid only after detecting the liquid level, avoiding the pipette from sucking up air, thereby improving the accuracy of pipetting.

[0088] Figure 6The diagram shows a schematic of the liquid aspiration state determination device provided in an embodiment of this application. The specific embodiments of this application do not limit the specific implementation of the liquid aspiration state determination device.

[0089] like Figure 6 As shown, the liquid aspiration status determination device 300 may include a processor 302 and a memory 304.

[0090] The memory 304 is used to store the computer program 306. The memory 304 may include high-speed RAM, and may also include non-volatile memory, such as at least one disk storage device. The computer program 306 may include computer-executable instructions.

[0091] The processor 302 is used to execute the computer program 306 to implement the above-described embodiment of the liquid aspiration state determination method.

[0092] Processor 302 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application. The liquid aspiration status determination device includes one or more processors, which may be processors of the same type, such as one or more CPUs; or processors of different types, such as one or more CPUs and one or more ASICs.

[0093] This application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described liquid aspiration state determination method embodiment.

[0094] This application provides a computer program that can be executed by a processor to implement the above-described liquid aspiration state determination method embodiment.

[0095] This application provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-described liquid aspiration state determination method embodiment.

[0096] In the several embodiments provided in this application, any function, if implemented as a software functional module / unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, part or all of the technical solutions of this application 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 personal computer, server, or other electronic device) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing computer program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0097] The algorithms or displays provided herein are not inherently related to any particular computer, virtual system, or other device. Various general-purpose systems can also be used in conjunction with the teachings herein. The required structure for constructing such systems is apparent from the above description. Furthermore, the embodiments of this application are not directed to any particular programming language. It should be understood that the content of this application described herein can be implemented using various programming languages, and the above description of specific languages ​​is for the purpose of disclosing the best mode of implementation of this application.

[0098] It should be noted that the above embodiments are illustrative of this application and not restrictive, and those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. This application can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In claims enumerating several means, several units or modules of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be construed as limiting the order of execution.

[0099] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for determining liquid aspiration status, applied to a pipetting system, characterized in that, The pipetting system includes a pipette, and the method includes: Control the pipette to descend until it is inserted into the sample solution; The internal air pressure of the pipette before it draws the sample liquid is obtained, and a first internal air pressure value is obtained; The pipette is controlled to draw the sample liquid, and during the process of the pipette drawing the sample liquid, the internal air pressure of the pipette is obtained at preset intervals of liquid volume, and multiple second internal air pressure values ​​are obtained in sequence. The internal air pressure after the pipette aspirates the sample liquid is obtained, and a third internal air pressure value is obtained; Calculate the difference between two adjacent second internal air pressure values ​​to obtain multiple first pressure differences in sequence; The difference between the first internal air pressure value and the third internal air pressure value is calculated to obtain the second pressure difference; If a first preset number of first pressure differences among a plurality of the first pressure differences are greater than a first gas pressure threshold, and the second pressure difference is greater than a second gas pressure threshold, then the liquid aspiration state of the pipette is determined to be aspiration blockage.

2. The method according to claim 1, characterized in that, The method further includes: If none of the multiple first pressure differences have a consecutive first preset number of first pressure differences greater than the first gas pressure threshold, and / or the second pressure difference is less than or equal to the second gas pressure threshold, then the pipette's suction state is determined to be non-blocked.

3. The method according to claim 1, characterized in that, After determining that the pipette's aspiration state is blocked, the method further includes: Control the pipette to eject the aspirated sample solution; A first alarm message is generated, which is used to indicate that the pipette is clogged.

4. The method according to claim 1, characterized in that, The method further includes: The slope of the pressure change of the pipette is calculated based on two adjacent second internal pressure values ​​among a plurality of second internal pressure values, and a plurality of pressure change slopes are obtained. The pressure change slope difference of the pipette is calculated based on two adjacent pressure change slopes among the multiple pressure change slopes, resulting in multiple slope difference values; If among the multiple slope differences there is a slope difference greater than a preset slope threshold, and the second pressure difference is less than a third gas pressure threshold, then the pipette's aspiration state is determined to be empty. If none of the slope differences is greater than the preset slope threshold, and / or the second pressure difference is greater than or equal to the third gas pressure threshold, then the pipette's aspiration state is determined to be not empty.

5. The method according to claim 4, characterized in that, After determining that the pipette's aspiration state is empty, the method further includes: Control the pipette to eject the aspirated sample solution; Control the pipette to rise above the surface of the sample solution, and then proceed to the step of controlling the pipette to descend into the sample solution; Once the pipette is confirmed to have emptied of liquid, a second alarm message is generated to indicate that the pipette has emptied.

6. The method according to claim 1, characterized in that, The control of the pipette descending to the point of being inserted into the sample solution further includes: The internal air pressure of the pipette located above the sample liquid is obtained to obtain a fourth internal air pressure value; The pipette is controlled to descend at a preset speed; During the descent of the pipette, the pipette is controlled to perform a blowing operation; During the blowing operation performed by the pipette, the internal air pressure of the pipette is acquired in real time to obtain a fifth internal air pressure value; The difference between the fifth internal air pressure value and the fourth internal air pressure value is calculated to obtain the third pressure difference; When the third pressure difference exceeds the fourth gas pressure threshold for a second consecutive preset number of times, the pipette is controlled to stop performing the blowing operation and to descend a preset distance to insert into the sample solution.

7. The method according to claim 6, characterized in that, The pipette includes a plunger; The step of controlling the pipette to perform a blowing operation during the descent of the pipette further includes: During the descent of the pipette, the plunger is controlled to move along a first direction to drive the pipette to perform a blowing operation; The step of controlling the pipette to stop performing the blowing operation when the third pressure difference is greater than the fourth gas pressure threshold for a second consecutive preset number of times further includes: When the third pressure difference exceeds the fourth gas pressure threshold for a second consecutive preset number of times, the plunger is controlled to stop moving, so that the pipette stops performing the blowing operation. The control of the pipette to aspirate the sample solution further includes: The plunger is controlled to move in the opposite direction to the first direction to drive the pipette to aspirate the sample solution.

8. A device for determining liquid aspiration status, comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the liquid aspiration state determination method according to any one of claims 1-7.

9. A pipetting system, characterized in that, The pipetting system includes: a pipette and the aspiration status determination device as described in claim 8, wherein a pressure sensor is provided on the pipette and the pressure sensor is communicatively connected to the aspiration status determination device; The liquid aspiration status determination device is used to control the pipette to descend or rise, and to control the pipette to aspirate sample liquid; The pressure sensor is used to acquire the internal air pressure of the pipette and send the internal air pressure of the pipette to the aspiration status determination device.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the liquid aspiration state determination method according to any one of claims 1-7.

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