A method of detecting a liquid level of a pipette reagent

Abstract

The application relates to the technical field of biochemical detection experiments, and discloses a method for detecting the liquid level of a reagent of a pipettor, which comprises the following steps: obtaining a current frequency value through a capacitance detection module, so that the frequency data is more clear and intuitive, and the data processing is simplified without conversion into a capacitance value; and pre-correlating and mapping the current frequency value of a jump with a reference frequency, so that the reference frequency is obtained by querying the current frequency value of the jump, so that when the real-time frequency slope is smaller than the reference frequency of the to-be-detected foam reagent, it is determined that the conductive probe enters the liquid level, the conductive probe enters the liquid level of the high-conductivity to-be-detected foam reagent simply and quickly, the current frequency value of the jump and the reference slope under the liquid level are quantified by using the conductive probe, the detection is simple and efficient, the detection result is ensured to be accurate, and the influence of foam on the liquid level detection on the liquid level of the to-be-detected foam reagent is effectively excluded.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biochemical detection experiment, and particularly relates to a method for detecting the liquid level of a reagent by a pipette. BACKGROUND

[0002] The pipette precisely extracts the reagent so as to perform subsequent biochemical detection. If the reagent dose cannot be precisely extracted, the experimental result may be invalid or incorrect. Therefore, accurately detecting whether the pipette enters the liquid level of the to-be-detected foamed reagent is one of important nodes in the pipetting process. However, the existing liquid level detection method is usually designed for low-conductivity reagents, and there is no effective method for precisely detecting whether the pipette enters the liquid level for high-conductivity reagents. Meanwhile, the capacitance value measured by the high-conductivity reagent is small but fluctuates greatly, and there is no clear liquid level demarcation point. SUMMARY

[0003] Therefore, the present application aims to provide a method for detecting the liquid level of a reagent by a pipette, which can accurately detect whether the pipette enters the liquid level of a high-conductivity reagent.

[0004] The present application provides a method for detecting the liquid level of a reagent by a pipette, the pipette comprising a conductive probe and a capacitance detection module connected with the conductive probe, and comprising the following steps.

[0005] Controlling the conductive probe to move towards the to-be-detected foamed reagent, acquiring a current frequency value based on the capacitance detection module;

[0006] When a jumping current frequency value appears, determining a reference frequency of the to-be-detected foamed reagent based on the jumping current frequency value;

[0007] Calculating a real-time frequency slope based on the real-time current frequency value;

[0008] When the real-time frequency slope is less than the reference frequency of the to-be-detected foamed reagent, determining that the conductive probe enters the liquid level.

[0009] Preferably, the step of acquiring the current frequency value based on the capacitance detection module comprises the following steps.

[0010] Acquiring a detection frequency value detected by the capacitance detection module;

[0011] Filtering the detection frequency value to acquire the current frequency value.

[0012] Preferably, the step of filtering the detection frequency value to acquire the current frequency value comprises the following steps.

[0013] Acquiring a measurement frequency variance and a prediction state variance at a previous moment, and calculating a filtering gain value at a current moment;

[0014] The current frequency value is obtained by filtering the detected frequency value and the predicted frequency value from the previous time using the current filter gain value.

[0015] Preferably, after obtaining the current frequency value, the method further includes:

[0016] Obtain the predicted state variance of the previous time step, calculate the current state variance based on the predicted state variance, and calculate the frequency difference between the predicted frequency value of the previous time step and the current frequency value of the current time step.

[0017] When the frequency difference is greater than the first preset difference, the current state variance is processed by the correction formula to obtain the predicted state variance value at the current time.

[0018] If the frequency difference is not greater than the first preset difference, the target formula is used to process the current state variance to obtain the predicted state variance value at the current time.

[0019] Based on the predicted state variance and measurement frequency variance at the current moment, obtain the filter gain value at the next moment;

[0020] The frequency value at the next time step is obtained based on the filter gain value at the next time step.

[0021] Preferably, the correction formula is as follows: p n+1,n =p n,n +kq n , where p n+1,n p represents the predicted state variance at time n. n,n Let q represent the current state variance at time n, k represent the coefficient of the noise variance in the compensation process, and q represent the current state variance at time n. n This represents the noise variance at time n.

[0022] Preferably, the target formula is p n+1,n =p n,n +q n , where p n+1,n p represents the predicted state variance at time n. n,n Let q represent the variance of the current state at time n. n This represents the noise variance at time n.

[0023] Preferably, for q n Make dynamic adjustments, q n =p*2*(|Predicted frequency value at the previous moment - Detected frequency value at the current moment|+b)+a, where p, b, and a are all constants, p is the correction coefficient, b is the correction parameter, and a is the compensation parameter.

[0024] Preferably, before the current frequency value of the jump occurs, the method further comprises:

[0025] The predicted frequency value of the previous moment and the detected frequency value of the current moment are obtained, and the frequency difference value of the two is calculated.

[0026] When the frequency difference value is greater than a second preset difference value, the current frequency value of the jump is determined.

[0027] Preferably, the reference frequency of the to-be-tested foam reagent is determined based on the current frequency value of the jump, including: based on the current frequency value of the jump, querying a reagent mapping table to obtain the volume of the to-be-tested foam reagent and the reference frequency corresponding to the volume.

[0028] Preferably, during the movement of the conductive probe towards the to-be-tested foam reagent, the movement speed of the conductive probe is controlled to be 110 mm / s.

[0029] The technical scheme of the embodiment of the present application has at least the following advantages and beneficial effects: whether the conductive probe enters the liquid surface of the to-be-tested foam reagent is converted into detecting two quantified parameters, i.e., the current frequency value of the jump and the reference slope under the liquid surface, so that the detection is simple and efficient, the detection result is accurate, and the influence of the foam on the liquid surface of the to-be-tested foam reagent on the liquid surface detection is effectively excluded. Specifically, the current frequency value is obtained by the capacitance detection module, the frequency data is more clear and intuitive, and there is no need to convert into a capacitance value, so that the data processing is simplified; the current frequency value of the jump is associated and mapped with a reference frequency in advance, and the reference frequency is obtained by querying based on the current frequency value of the jump, so that when the real-time frequency slope is less than the reference frequency of the to-be-tested foam reagent, it is determined that the conductive probe enters the liquid surface, the conductive probe entering the liquid surface of the high-conductivity to-be-tested foam reagent is determined simply and quickly, the detection method is simplified, and support is provided for subsequent biochemical experiments. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The flowchart of the method for detecting the liquid surface of the reagent by the pipettor provided by the embodiment of the present application is shown;

[0031] Figure 2 The circuit diagram of the method for detecting the liquid surface of the reagent by the pipettor provided by the embodiment of the present application is shown. DETAILED DESCRIPTION

[0032] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described clearly and completely below with specific embodiments. The same reference signs in the drawings represent the same components. It should be noted that the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort fall within the scope of protection of the present application.

[0033] As shown in Figure 1 The present application provides a method for detecting the liquid level of a reagent by a pipette, the pipette comprising a conductive probe and a capacitance detection module connected to the conductive probe, comprising the following steps:

[0034] S100: moving the conductive probe towards a foam reagent to be detected, and obtaining a current frequency value based on the capacitance detection module.

[0035] S200: when a jumping current frequency value appears, determining a reference frequency of the foam reagent to be detected based on the jumping current frequency value.

[0036] S300: calculating a real-time frequency slope based on the real-time current frequency value.

[0037] S400: when the real-time frequency slope is less than the reference frequency of the foam reagent to be detected, determining that the conductive probe enters the liquid level.

[0038] The method of the present application is based on Figure 2 the circuit implementation shown in Figure 2 In the circuit implementation, the conductive probe of the pipette is a variable capacitance monopole plate 10, the resonant circuit 20 comprises a parallel capacitance sensor, an inductance L of the capacitance sensor and a capacitance C, the capacitance sensor (CapSensor) is used to detect the capacitance change of the monopole plate 10, the L and C of the resonant circuit 20 are used to provide a basic frequency, and the resonant frequency is determined by the inductance L, the fixed capacitance C and the capacitance of the monopole plate 10 (i.e. the conductive probe) detected by the capacitance sensor, so that when the capacitance of the conductive probe changes, the resonant frequency (i.e. the current frequency value) changes accordingly. The LC resonant chip 30 provides an oscillation driving circuit (Resonant circuit driver) and an oscillation frequency measurement circuit (i.e. the capacitance detection module), the oscillation driving circuit is connected to both ends of the resonant circuit 20 through pins (such as INOA and INOB) to manage and maintain the oscillation of the external resonant circuit 20. The oscillation frequency measurement circuit is used to detect the resonant frequency and transmit the resonant frequency in real time through the I 2The C communication 40 is sent to the single-chip microcomputer MCU. Understandably, when the capacitance of the conductive probe changes, the resonant frequency changes in real time, so that the change of the capacitance of the conductive probe is measured through the change of the frequency, so as to subsequently detect whether the conductive probe enters the liquid level of the foam reagent to be detected. Figure 2 I, wherein I 2 C periphera is a peripheral device, I 2 C is a bus, and Int. Osc. is an internal oscillator. The oscillation frequency measurement circuit of the resonant chip 30 includes a core, which is connected with a standard crystal oscillator of 40 MHz and an internal oscillator, one of which serves as a reference clock of the core.

[0039] The reference slope is determined in advance, and the frequency slope detected when the conductive probe enters the liquid level of the foam reagent without foam, and the properties of the foam reagent without foam are the same as those of the foam reagent to be detected, specifically the same volume and the same solution type.

[0040] In the embodiment, the method for detecting whether the conductive probe enters the liquid level of the foam reagent to be detected is converted into detecting two quantified parameters, i.e., the current frequency value of the jump and the reference slope under the liquid level, so that the detection is simple and efficient, the detection result is accurate, and the influence of the foam on the liquid level on the detection of the liquid level is effectively excluded. Specifically, the current frequency value is obtained through the capacitance detection module, the frequency data is more clear and intuitive, and it is not necessary to convert the capacitance value, so that the data processing is simplified; the current frequency value of the jump is associated with the reference frequency in advance, and the reference frequency is obtained through the current frequency value of the jump, so that when the real-time frequency slope is less than the reference frequency of the foam reagent to be detected, it is determined that the conductive probe enters the liquid level, the conductive probe entering the liquid level of the high-conductivity foam reagent to be detected is determined simply and conveniently, the detection method is simplified, and support is provided for subsequent biochemical experiments.

[0041] In an embodiment, since the frequency waveform jitter is large, the original frequency data is directly used, and errors are prone to occur. Based on this, the original frequency value is filtered to eliminate jitter as much as possible. In step S100, the current frequency value obtained based on the capacitance detection module includes: collecting the detected frequency value detected by the capacitance detection module; and filtering the detected frequency value to obtain the current frequency value. The frequency of the high-conductivity foam reagent to be detected is small and fluctuates greatly, which brings great difficulty to accurately detect whether the conductive probe enters the liquid level, and filtering the detected frequency value can effectively eliminate jitter and ensure the accuracy of the detection result.

[0042] In an embodiment, the filtering the detected frequency value to obtain the current frequency value comprises: obtaining a measurement frequency variance and a predicted state variance of a previous time, and calculating a filtering gain value of a current time; filtering the detected frequency value and the predicted frequency value of the previous time by using the filtering gain value of the current time to obtain the current frequency value.

[0043] In the embodiment, the predicted state variance of the previous time and the predicted frequency value of the previous time are used to calculate the current frequency value of the current time, data filtering is realized, noise is removed, and the accuracy of the current frequency value is ensured.

[0044] Specifically, K n = p n,n-1 / (p n,n-1 +r n ), wherein K n represents the filtering gain of the n time; p n,n-1 represents the predicted state variance of the previous time of the n time, r n represents the measurement frequency variance of the n time, and r n is a constant value in the embodiment.

[0045] , wherein represents the predicted frequency value of the n time, X n represents the detected frequency value of the n time, and represents the predicted frequency value of the n-1 time.

[0046] In an embodiment, after the current frequency value is obtained, the method further comprises:

[0047] obtaining a predicted state variance of a previous time, calculating a current state variance based on the predicted state variance, and calculating a frequency difference value between a predicted frequency value of the previous time and a current frequency value of the current time;

[0048] when the frequency difference value is greater than a first preset difference value, processing the current state variance by using a correction formula to obtain a predicted state variance value of the current time;

[0049] when the frequency difference value is not greater than the first preset difference value, processing the current state variance by using a target formula to obtain the predicted state variance value of the current time;

[0050] obtaining a filtering gain value of a next time based on the predicted state variance value of the current time and the measurement frequency variance;

[0051] obtaining a next time frequency value based on the filtering gain value of the next time.

[0052] The first preset difference is a pre-set value. In this embodiment, different formulas are used to process the current state variance based on the frequency difference. When the frequency difference is greater than the first preset difference, a correction formula is used to correct the current state variance. In other words, when the frequency difference is greater than the first prediction difference, the predicted state variance is proportionally processed, and the frequency value at the next moment is obtained based on the predicted state variance at the current moment. This ensures that the frequency value at the next moment is closer to the detection frequency value at the next moment, avoiding misjudged frequency jumps and guaranteeing the accuracy of the detection effect.

[0053] Specifically, the correction formula is as follows: p n+1,n =p n,n +kq n , where p n+1,n p represents the predicted state variance at time n. n,n Let q represent the current state variance at time n, k represent the coefficient of the noise variance in the compensation process, and q represent the current state variance at time n. n Let p represent the noise variance at time n. The objective formula is p. n+1,n =p n,n +q n , where p n+1,n p represents the predicted state variance at time n. n,n Let q represent the variance of the current state at time n. n Let represent the noise variance at time n. In this embodiment, for q... n Make dynamic adjustments, q n =p*2*(|Predicted frequency value at the previous time - Detected frequency value at the current time| + b) + a, where p, b, and a are constants, p is the correction coefficient, b is the correction parameter, and a is the compensation parameter. In this embodiment, the difference between the predicted frequency value at time n-1 and the detected frequency value at time n is used to calculate q. n Dynamic adjustments are made to ensure the accuracy of test results.

[0054] As an example, before step S200, that is, before the current frequency value of the jump occurs, the method further includes: obtaining the predicted frequency value of the previous moment and the detected frequency value of the current moment, and calculating the frequency difference between the two; when the frequency difference is greater than a second preset difference, the current frequency value of the jump is determined.

[0055] In the embodiment, the conductive probe does not contact the to-be-tested foam reagent at the beginning of moving towards the to-be-tested foam reagent, and the conductive medium at this time is air; when the conductive probe contacts the to-be-tested foam reagent, the conductive medium at this time is the foam of the to-be-tested foam reagent, and the conductive medium changes, and the detection frequency value also jumps. By continuously detecting the detection frequency value at the current time, the difference between the predicted frequency value at the previous time and the actually detected detection frequency value at the current time is greater than the second preset difference value, it is indicated that the current frequency value jumps. The second preset difference value is a preset difference value, and the second preset difference value is greater than the first preset difference value.

[0056] As an embodiment, in step S200, the reference frequency of the to-be-tested foam reagent is determined based on the current frequency value of the jump, including: based on the current frequency value of the jump, querying a reagent mapping table to obtain the volume of the to-be-tested foam reagent and the reference frequency corresponding to the volume. Specifically, the pipette is controlled in advance to detect a plurality of bubble-free reagents of different volumes and different types, and when the conductive probe enters the liquid surface of the bubble-free reagent, the detected jump frequency is recorded, and the frequency slope after the jump is calculated based on the real-time frequency to obtain the reference slope, and the jump frequency, volume, reagent type and reference slope of the bubble-free reagent are recorded in the reagent mapping table. Therefore, when the current frequency value of the jump of the to-be-tested foam reagent is obtained, the reagent mapping table is queried based on the current frequency value to obtain the jump frequency corresponding to the current frequency value, and the reference slope is determined based on the jump frequency.

[0057] As an embodiment, the moving speed of the conductive probe towards the to-be-tested foam reagent is controlled to be 110 mm / s.

[0058] The above is only a preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for detecting reagent liquid level using a pipette, the pipette comprising a conductive probe and a capacitance detection module connected to the conductive probe, characterized in that, include: The conductive probe is controlled to move toward the foam reagent to be tested, and the current frequency value is obtained based on the capacitance detection module; When a jump occurs in the current frequency value, the reference frequency of the foam reagent to be tested is determined based on the jump in the current frequency value. The real-time frequency slope is calculated based on the current real-time frequency value. If the real-time frequency slope is less than the reference frequency of the foam reagent to be tested, then it is determined that the conductive probe has entered below the liquid surface. The step of obtaining the current frequency value based on the capacitance detection module includes: Collect the detection frequency value detected by the capacitance detection module; The detected frequency value is filtered to obtain the current frequency value; The step of filtering the detected frequency value to obtain the current frequency value includes: Obtain the measurement frequency variance and the predicted state variance of the previous moment, and calculate the filter gain value at the current moment; The current frequency value and the predicted frequency value from the previous moment are filtered using the current filter gain value to obtain the current frequency value. Obtain the predicted state variance of the previous time step, calculate the current state variance based on the predicted state variance, and calculate the frequency difference between the predicted frequency value of the previous time step and the current frequency value of the current time step. When the frequency difference is greater than the first preset difference, the current state variance is processed by the correction formula to obtain the predicted state variance value at the current time. If the frequency difference is not greater than the first preset difference, the target formula is used to process the current state variance to obtain the predicted state variance value at the current time. Based on the predicted state variance and measurement frequency variance at the current moment, obtain the filter gain value at the next moment; The frequency value at the next time step is obtained based on the filter gain value at the next time step.

2. The method for detecting reagent liquid level using a pipette according to claim 1, characterized in that, The correction formula is p n+1,n =p n,n +kq n , where p n+1,n p represents the predicted state variance at time n. n,n Let q represent the current state variance at time n, k represent the coefficient of the noise variance in the compensation process, and q represent the current state variance at time n. n This represents the noise variance at time n.

3. The method for detecting reagent liquid level using a pipette according to claim 1, characterized in that, The target formula is p n+1,n =p n,n +q n , where p n+1,n p represents the predicted state variance at time n. n,n Let q represent the variance of the current state at time n. n This represents the noise variance at time n.

4. The method for detecting reagent liquid level using a pipette according to claim 2 or 3, characterized in that, For q n Make dynamic adjustments, q n =p*2*(|Predicted frequency value at the previous moment - Detected frequency value at the current moment|+b)+a, where p, b, and a are all constants, p is the correction coefficient, b is the correction parameter, and a is the compensation parameter.

5. The method for detecting reagent liquid level using a pipette according to claim 1, characterized in that, Prior to the occurrence of the current frequency value that jumps, the method further includes: Obtain the predicted frequency value from the previous moment and the detected frequency value from the current moment, and calculate the frequency difference between the two. When the frequency difference is greater than the second preset difference, the current frequency value where the jump occurs is determined.

6. The method for detecting reagent liquid level using a pipette according to claim 1, characterized in that, Determining the reference frequency of the foam reagent to be tested based on the current frequency value of the jump includes: querying a reagent mapping table based on the current frequency value of the jump to obtain the volume of the foam reagent to be tested and the reference frequency corresponding to the volume.

7. The method for detecting reagent liquid level using a pipette according to claim 1, characterized in that, During the movement of the conductive probe toward the foam reagent to be tested, the moving speed of the conductive probe is controlled to be 110 mm / s.

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