An automatic dilution dispensing apparatus and method

Abstract

The application discloses an automatic dilution standard solution preparation device and method, and relates to the field of analytical chemistry pretreatment equipment. The device comprises a multi-channel valve, a syringe pump, a three-way electromagnetic valve, a mixing pipe and a device shell. The distribution port of the multi-channel valve is connected with a standard solution channel, a dilution solution channel, a cleaning solution channel and an air pipeline with a needle type filter. The syringe pump quantitatively sucks the standard solution and the dilution solution through the multi-channel valve and then discharges the standard solution and the dilution solution into the mixing pipe for mixing. The three-way electromagnetic valve has two working states and can automatically switch between sample injection analysis and pipeline cleaning. The air pipeline is used for sucking filtered air to assist mixing and pipeline purging. The application has the advantages of simple structure, controllable cost, online automatic switching of standard solution preparation, sample injection and cleaning, effective reduction of cross contamination, strong expandability and suitability for pretreatment scenes of various analytical instruments.

Description

Technical Field

[0001] This invention relates to the field of analytical chemistry pretreatment equipment technology, specifically to an automatic dilution and standard preparation device and method, mainly used for the automatic preparation of standard curves, online sample dilution, and quality control sample preparation for analytical instruments such as chromatography and mass spectrometry. Background Technology

[0002] In analytical chemistry, the preparation of standard curves is a fundamental step in quantitative analysis, and its accuracy directly determines the reliability of the final detection results. Traditional standard curve preparation involves manual, offline operations. Researchers must use pipettes, volumetric flasks, and other glass instruments to manually measure, dilute, and bring the stock solution to volume following a stepwise dilution process. This method suffers from numerous drawbacks, including poor quantitative accuracy, low data reproducibility, severe exogenous contamination, extremely low analytical efficiency, high labor and consumable costs, lack of quality control and traceability, and high safety risks. It cannot meet the stringent requirements of precision and reproducibility in ultra-trace analysis, nor does it comply with the management requirements of modern digital laboratories.

[0003] To address the aforementioned shortcomings, those skilled in the art have gradually developed various automated labeling and dilution technologies. In micro-quantitation, ceramic syringe pump technology has been widely used in chromatographic and mass spectrometric pretreatment equipment since 2000. It employs a ceramic piston with a fully PFA sealed structure, using a stepper motor to drive the plunger for precise liquid intake and discharge. Single-channel volumetric quantification accuracy can reach within ±0.05%, effectively solving the flow rate drift defect caused by the elasticity of the tubing in traditional peristaltic pumps. Regarding multi-path switching, multi-channel electromagnetic switching valves have been introduced into labeling systems. A single valve allows switching between multiple mother liquor channels, enabling the preparation of multi-concentration standard solutions with only a single stock solution. Internationally, ESI (Energy Sequencing Institute) launched the world's first prepFAST online labeling system between 2000 and 2010, integrating a ceramic syringe pump and a fully PFA flow path into the ICP-MS injection front end for the first time. Agilent Technologies simultaneously developed the ADS series of original equipment manufacturer (OEM) dilution modules, emphasizing integrated software and primarily used in overseas semiconductor industries and large testing laboratories. However, the equipment is expensive, resulting in low adoption rates in China. In China, from 2010 to 2020, LabTech launched the MiniLab-O fully automated dilution and labeling instrument, which adopts a dual-pump design to accommodate both inorganic and organic labeling scenarios. The Weidu PAW-36 and Piken Elab-20 series products employ multi-channel parallel pipetting, offering lower cost and smaller footprint. Ruike's fully automated liquid workstation attempts to integrate pretreatment extraction and labeling functions. However, these domestically produced devices are still imperfect in terms of online linkage functions and over-dilution capabilities. Fluid control accuracy and flow path corrosion prevention processes still lag behind imported equipment. Furthermore, the simplified semi-automatic peristaltic pump dilution scheme relies on a dual-channel peristaltic pump to adjust the speed ratio of the two pump tubes to control the mixing ratio of mother liquor and diluent. Lacking a precision injection metering unit, its pump tubes suffer from aging and deformation due to long-term compression, resulting in severe flow drift and making it unsuitable for ppb-level trace standard preparation.

[0004] The prior art, which is similar to this application, includes: Chinese invention patent CN108627657A, which discloses a liquid path system that uses a dual pump and multiple three-way solenoid valves to form a diluent aspiration and injection flow path, and uses magnetic beads for stirring to mix the sample with the diluent. However, this solution requires three pumps and five three-way solenoid valves to work together, resulting in high system complexity. Moreover, its technical field is immunoassay analyzers and does not involve direct linkage with the sample injection line of the analyzer. CN109283138A discloses a quantitative injection system that uses a multi-way valve and an injection pump to select and introduce water samples, reagents, or cleaning solutions. The multi-way valve is expanded by using a solenoid valve assembly, but it does not have a connection to the sample injection line. The cleaning and switching structure of the present application is not disclosed, nor is the specific implementation method of air-assisted mixing disclosed. CN112051127A discloses a biological fluid sample preparation and mixing device, which adopts a dual pump structure of diluent injection pump and mother liquor injection pump, and uses replaceable pipette tips to avoid cross-contamination. However, it relies on disposable pipette tip consumables, resulting in high operating costs. The technical field is also significantly different from that of this application. CN114235545A discloses a high-precision sample injection system, which uses an injection pump with two multi-channel directional valves and an independent liquid storage module to achieve stirring and mixing through air bubbling. However, it requires dual valves and an independent liquid storage module, making the structure relatively complex. Furthermore, it does not have a three-way valve structure that can switch the sample injection line of the analytical instrument with the cleaning liquid source.

[0005] The aforementioned existing technical solutions generally suffer from the following shortcomings: First, existing equipment often employs a dual-pump or even multi-pump structure with multiple switching valves, resulting in complex systems, high hardware costs, and increased system failure probability and maintenance difficulty due to multi-pump coordinated control. Second, while existing solutions combine multi-way valves with syringe pumps, none feature a three-way solenoid valve structure capable of online switching between the analytical instrument's sample inlet line and the cleaning fluid source. Manual switching of the pipeline is required after labeling, which is cumbersome and prone to introducing contamination. Third, although some existing solutions utilize air-assisted mixing technology, their air inlets are often directly connected to the atmosphere without filtration, allowing airborne particles to enter the flow path and cause contamination. Fourth, existing solutions often employ magnetic bead stirring or independent stirring devices, requiring additional components within the mixing container, increasing structural complexity and contamination risk. Fifth, existing solutions mostly adopt standardized overall architectures, failing to support customized miniaturization and online monitoring integration. Based on these issues, there is an urgent need in this field for an automated dilution and labeling device that is structurally simplified, cost-controllable, capable of online switching between labeling and sample inlet cleaning, and ensures labeling accuracy. Summary of the Invention

[0006] This invention addresses the technical problems of existing automatic dilution and labeling devices being expensive and complex in structure, by providing an automatic dilution and labeling device and method that is simple in structure, low in cost, and has high-precision automatic labeling function, aiming to provide the market with more choices.

[0007] To solve the above-mentioned technical problems, the technical solution proposed in this application is as follows:

[0008] This invention provides an automatic dilution and labeling device, comprising: A multi-channel valve has a common port and multiple distribution ports, the multiple distribution ports including a standard solution channel for connecting to a standard solution source, a diluent channel for connecting to a diluent source, a cleaning solution channel for connecting to a cleaning solution source, and an air distribution port connected to an air line; An injection pump, connected to the common port of the multi-channel valve via tubing, is used for metering the intake and discharge of liquid; A mixing tube is used to receive and mix the standard solution and diluent discharged by the syringe pump; The three-way solenoid valve has a first port, a second port and a third port. The first port is used to connect to the sample injection line of the analytical instrument, the second port is used to connect to the cleaning solution source, and the third port is connected to the mixing tube. The three-way solenoid valve has a first working state and a second working state. In the first working state, the first port and the third port are connected, so that the sample injection line of the analytical instrument is connected to the mixing tube for sample injection analysis. In the second working state, the second port and the third port are connected, so that the cleaning solution source is connected to the sample injection line of the analytical instrument for line cleaning. A needle filter is provided at the end of the air pipeline. The injection pump draws in air filtered by the needle filter through the common port of the multi-channel valve and the air distribution port, and discharges the air into the mixing tube.

[0009] Furthermore, the multi-channel valve is a twelve-channel valve, the common port of the twelve-channel valve is connected to the inlet of the injection pump, and the twelve distribution ports of the twelve-channel valve are respectively connected to the standard solution channel, the diluent channel, the cleaning solution channel, the air channel, the mixing output channel and the waste liquid channel.

[0010] Furthermore, a mixing output channel is provided on the pipeline between the mixing tube and the third port of the three-way solenoid valve. The mixing output channel is connected to one distribution port of the multi-channel valve. The injection pump draws the mixture from the mixing tube through the multi-channel valve and discharges the mixture back into the mixing tube through the mixing output channel to achieve repeated mixing.

[0011] Furthermore, the volume of the mixture drawn by the injection pump from the mixing tube through the multi-channel valve is more than two-thirds of the total volume of the mixture in the mixing tube.

[0012] Furthermore, the injection pump is a stepper motor driven plunger injection pump, the pump body of the injection pump is made of ceramic material, and the flow path pipes in the device are made of all PFA material.

[0013] Furthermore, the device also includes a housing and a control unit. The multi-channel valve, the injection pump, the three-way solenoid valve, and the mixing tube are all integrated and installed inside the housing. The control unit is electrically connected to the injection pump, the multi-channel valve, and the three-way solenoid valve. The control unit is configured to calculate the standard solution aspiration volume and the diluent aspiration volume based on the input dilution factor and the fixed volume, and to control the injection pump and the multi-channel valve to sequentially complete the standard solution aspiration, diluent aspiration, mixture discharge, and mixing operations.

[0014] Furthermore, one distribution port of the multi-channel valve is a matrix matching liquid channel, and the other distribution port is a spiking liquid channel. The matrix matching liquid channel and the spiking liquid channel are respectively connected to the corresponding reagent sources.

[0015] Furthermore, a constant temperature heating device is provided on the outer wall of the mixing tube, which is used to control the temperature of the liquid inside the mixing tube.

[0016] On the other hand, this application also claims protection for an automatic dilution and labeling method, implemented using the automatic dilution and labeling device described in any of the foregoing, comprising the following steps: S1: Prepare the standard curve, including the following sub-steps: S11: Switch the multi-channel valve to the standard solution channel, and the syringe pump draws the first volume of standard solution; S12: Switch the multi-channel valve to the diluent channel, and the syringe pump draws a second volume of diluent; S13: The syringe pump pumps the aspirated standard solution and diluent together into the mixing tube, where the standard solution and diluent are mixed to form the first concentration standard solution; S14: Repeat steps S11 to S13, and by changing the ratio of the first volume to the second volume, prepare a series of standard curve points with different concentrations. S2: Sample injection analysis, including the following sub-steps: S21: The three-way solenoid valve switches to the first working state, so that the sample injection line of the analyzer is connected to the mixing tube through the three-way solenoid valve; S22: The analytical instrument draws the prepared standard solution from the mixing tube for testing; S3: Clean the pipeline, including the following sub-steps: S31: The three-way solenoid valve switches to the second working state, so that the cleaning fluid source is connected to the sample injection line of the analyzer through the three-way solenoid valve; S32: The cleaning solution flows into the sample inlet line of the analyzer to clean the sample inlet line.

[0017] Furthermore, step S13 is followed by a mixing step S131: Switch the multi-channel valve to the mixing output channel. The syringe pump draws more than two-thirds of the volume of the mixture from the mixing tube and then discharges it back into the mixing tube through the mixing output channel, so that the standard solution and the diluent are fully mixed.

[0018] Furthermore, it also includes a high-concentration sample dilution step S4: S41: Switch the multi-channel valve to the high-concentration sample channel, and the syringe pump draws the first volume of high-concentration sample. S42: Switch the multi-channel valve to the diluent channel, and the syringe pump draws a second volume of diluent; S43: The syringe pump pumps the aspirated high-concentration sample and diluent together into the mixing tube. The high-concentration sample and diluent mix in the mixing tube to form a diluted sample solution. S44: The three-way solenoid valve switches to the first working state, and the analytical instrument draws the diluted sample solution from the mixing tube for detection.

[0019] Compared with the prior art, the present invention achieves the following beneficial technical effects: This invention employs a simplified structure with a single injection pump and a multi-channel valve, significantly reducing hardware costs and system complexity. Simultaneously, a three-way solenoid valve enables automatic switching between online sample injection and cleaning without manual intervention, effectively reducing the risk of cross-contamination. A needle filter at the end of the air pipeline ensures the cleanliness of the air used for auxiliary mixing and purging, preventing the introduction of external contaminants. The overall structure is compact and highly expandable, adaptable to various analytical instruments and application scenarios, significantly improving labeling efficiency, automation level, and data reliability, while reducing laboratory operation and maintenance costs. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the automatic dilution and labeling device of the present invention.

[0022] In the diagram: 1-Multi-channel valve, 2-Injection pump, 3-Three-way solenoid valve, 4-Mixing tube, 5-Device housing. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] like Figure 1 As shown, this invention provides an automatic dilution and labeling device, mainly comprising a multi-channel valve 1, a syringe pump 2, a three-way solenoid valve 3, a mixing tube 4, and a device housing 5. The multi-channel valve 1 has a common port and multiple distribution ports. The multiple distribution ports include a standard solution channel for connecting to a standard solution source, a diluent channel for connecting to a diluent source, a cleaning solution channel for connecting to a cleaning solution source, and an air distribution port connected to an air line. The syringe pump 2 is connected to the common port of the multi-channel valve 1 via a pipeline for quantitatively drawing and discharging liquid. The mixing tube 4 is used to receive and mix the standard solution and diluent discharged by the syringe pump 2. The three-way solenoid valve 3 has a first port, a second port, and a third port. The first port is used to connect to the sample injection line of an analytical instrument, the second port is used to connect to the cleaning solution source, and the third port is connected to the mixing tube 4. The three-way solenoid valve 3 has a first working state and a second working state. In the first working state, the first port and the third port are connected, connecting the sample injection line of the analytical instrument to the mixing tube 4 for sample injection analysis. In the second working state, the second port and the third port are connected, connecting the cleaning solution source to the sample injection line of the analytical instrument for line cleaning. A needle filter is provided at the end of the air line. The syringe pump 2 draws in air filtered by the needle filter through the common port of the multi-channel valve 1 and the air distribution port, and discharges the air into the mixing tube 4.

[0025] In one embodiment of this application, the multi-channel valve 1 is a twelve-channel valve, i.e., it has one common port and twelve distribution ports. The common port of the twelve-channel valve is connected to the inlet of the syringe pump 2, and the twelve distribution ports of the twelve-channel valve are respectively connected to the standard solution channel, diluent channel, cleaning solution channel, air channel, mixing output channel, and waste liquid channel. The remaining distribution ports can be connected to the matrix matching liquid channel, the spiked solution channel, or other auxiliary liquid channels according to actual usage requirements. As the core hub node of the liquid circuit system, the standard solution channel, diluent channel, cleaning solution channel, air channel, mixing output channel, and waste liquid channel achieve spatial convergence and separation within the valve body of the multi-channel valve 1, eliminating the complex pipeline connections and multi-valve combination design of traditional labeling equipment. The overall number of liquid circuit components is significantly reduced, the dead volume of the pipeline is effectively reduced, and the reliability and maintenance convenience of the system are greatly improved.

[0026] In one embodiment of this application, a mixing output channel is provided on the pipeline between the mixing tube 4 and the third port of the three-way solenoid valve 3. The mixing output channel is connected to a distribution port of the multi-channel valve 1. After the standard solution and diluent are discharged into the mixing tube 4 by the syringe pump 2, the syringe pump 2 draws the mixture from the mixing tube 4 through the multi-channel valve 1 and discharges the mixture back into the mixing tube 4 through the mixing output channel to achieve repeated mixing. Specifically, the control unit controls the multi-channel valve 1 to switch to the mixing output channel, so that the common port of the multi-channel valve 1 is connected to the distribution port connected to the mixing tube 4. Then, the syringe pump 2 draws a certain volume of the mixture from the mixing tube 4 and discharges it back into the mixing tube 4 through the mixing output channel. This draw-discharge process can generate strong liquid turbulence in the mixing tube 4, so that the standard solution and diluent are fully mixed at the molecular level. The above-mentioned draw-discharge mixing operation can be repeated multiple times.

[0027] In one embodiment of this application, the volume of the mixture drawn from the mixing tube 4 by the injection pump 2 through the multi-channel valve 1 is at least two-thirds of the total volume of the mixture in the mixing tube 4. This ratio is set to ensure that each suction / discharge operation drives the majority of the liquid in the mixing tube 4 to participate in flow and mixing, thereby achieving thorough mixing with fewer suction / discharge operations. If the suction ratio is too low, only a small amount of liquid in the upper part of the mixing tube 4 participates in circulation, while the liquid in the lower part is difficult to agitate sufficiently, significantly reducing mixing efficiency. By setting the suction ratio to at least two-thirds, the liquid in the mixing tube 4 can form a convective circulation throughout the entire tube during each suction / discharge process, thereby achieving the best mixing effect with the fewest operations.

[0028] In one embodiment of this application, the syringe pump 2 is a stepper motor-driven plunger syringe pump. The pump body of the syringe pump 2 is made of ceramic material, and the flow path piping within the device is made entirely of PFA material. The stepper motor provides precise angular displacement control, and in conjunction with a high-precision lead screw transmission mechanism, converts the rotational motion of the motor into the linear reciprocating motion of the plunger, thereby achieving precise measurement of liquid volume. The ceramic pump body has extremely high hardness, wear resistance, and corrosion resistance, ensuring a long-term precise fit between the plunger and the pump body, effectively reducing the leakage rate. The all-PFA piping has excellent chemical corrosion resistance, capable of withstanding long-term immersion in strong acids, strong alkalis, and organic solvents without swelling or degradation, ensuring the long-term stability and service life of the flow path in corrosive standard solution environments.

[0029] In one embodiment of this application, the multi-channel valve 1, the syringe pump 2, the three-way solenoid valve 3, and the mixing tube 4 are all integrated and installed inside the device housing 5. The device housing 5 provides protection and support for the internal components, while also shielding the liquid circuit system from external light and dust interference. The integrated installation method makes the entire device compact and small in size. The device also includes a control unit, which is electrically connected to the syringe pump 2, the multi-channel valve 1, and the three-way solenoid valve 3. The control unit is configured to calculate the standard solution aspiration volume and the diluent aspiration volume based on the input dilution factor and the final volume, and control the syringe pump 2 and the multi-channel valve 1 to sequentially complete the standard solution aspiration, diluent aspiration, mixture discharge, and mixing operations. Specifically, users can input the target dilution ratio and final volume through a touchscreen or host computer software connected to the control unit. The control unit automatically calculates the required volume according to the formulas "standard solution aspiration volume = final volume / dilution ratio" and "diluent aspiration volume = final volume - standard solution aspiration volume". Then, it controls the actions of each component in sequence according to the preset program timing. Users only need to input the target dilution ratio and final volume, and the device can automatically complete the entire labeling process.

[0030] In one embodiment of this application, one distribution port of the multi-channel valve 1 is a matrix matching solution channel, and the other distribution port is a spiking solution channel. The matrix matching solution channel and the spiking solution channel are respectively connected to corresponding reagent sources. The matrix matching solution is a solution containing a matrix composition similar to that of the sample to be tested. Adding the matrix matching solution when preparing a standard curve ensures that the matrix of the standard curve is consistent with the sample matrix, eliminating the influence of matrix effects on the detection results. The spiking solution is a standard solution containing a known concentration of the analyte, used to prepare spiked quality control samples to verify the accuracy of the detection method. By reserving matrix matching solution and spiking solution channels on the multi-channel valve 1, this device can not only prepare conventional standard curves but also automatically complete the online addition of matrix matching solution and the preparation of spiked quality control samples in one stop.

[0031] In one embodiment of this application, a constant-temperature heating device is provided on the outer wall of the mixing tube 4. This device is used to maintain a constant temperature for the liquid within the mixing tube 4. The constant-temperature heating device can be a closed-loop temperature control system composed of a resistance heating film, a heating rod, or a semiconductor cooling chip, along with a temperature sensor and a temperature control circuit. For certain standard solutions that are prone to crystallization at low temperatures, such as high-concentration salt standard solutions, the constant-temperature heating device can maintain the temperature within the mixing tube 4 near a set value, preventing crystallization due to temperature changes during preparation and ensuring the accuracy of the standard solution concentration and the success rate of preparation.

[0032] The automatic dilution and labeling method of the present invention will be described in detail below with reference to the above-described device structure.

[0033] The automatic dilution and standard preparation method of the present invention mainly includes a standard curve preparation process, a sample injection and analysis process, and a tubing cleaning process.

[0034] In the standard curve preparation process S1, the first step S11 is as follows: The control unit controls the multi-channel valve 1 to switch to the standard solution channel, so that the common port of the multi-channel valve 1 is connected to the standard solution channel connected to the standard solution source. Then, the injection pump 2 is controlled to draw standard solution from the standard solution source according to a preset first volume. The volume drawn by the injection pump 2 is precisely controlled by the number of rotation steps of the stepper motor to ensure the accuracy of the drawn volume. The specific operation process of step S11 is as follows: The control unit sends a switching command to the drive motor of the multi-channel valve 1. The drive motor drives the valve core to rotate to the corresponding angle position of the standard solution channel, so that the common port and the standard solution channel are connected inside the valve body. Then, the control unit sends a pulse signal to the stepper motor of the injection pump 2. The stepper motor rotates according to the preset number of pulses, and drives the plunger to move backward through the lead screw drive, forming a negative pressure inside the pump body, drawing the standard solution from the standard solution source into the pump chamber of the injection pump 2 through the common port of the multi-channel valve 1.

[0035] Then, proceed to step S12: switch the multi-channel valve 1 to the diluent channel, making the common port of the multi-channel valve 1 connected to the diluent channel connected to the diluent source, and then control the syringe pump 2 to draw diluent from the diluent source according to a preset second volume. The operation process of step S12 is similar to that of step S11, the difference being that the multi-channel valve 1 is switched to the diluent channel instead of the standard solution channel. It should be noted that the order of steps S11 and S12 can be adjusted according to actual needs, and the diluent can be drawn first and then the standard solution can be drawn; both orders can achieve the purpose of this invention.

[0036] Then, step S13 is performed: the syringe pump 2 discharges the drawn standard solution and diluent together into the mixing tube 4. The standard solution and diluent are initially mixed in the mixing tube 4 to form a standard solution of the first concentration. The specific operation process of step S13 is as follows: the control unit sends a reverse pulse signal to the stepper motor of the syringe pump 2, the stepper motor rotates in reverse, and drives the plunger forward through the lead screw drive, pushing the liquid in the pump chamber out into the mixing tube 4 through the common port of the multi-channel valve 1 and the mixing output channel. The ratio of the first volume to the second volume is determined according to the target dilution factor input by the user. For example, if the target dilution factor is 10 times and the fixed volume is 10 ml, then the first volume is 1 ml and the second volume is 9 ml.

[0037] Following step S13, a preferred mixing step S131 is performed: the multi-channel valve 1 is switched to the mixing output channel, and the syringe pump 2 draws more than two-thirds of the volume of the mixture from the mixing tube 4, then discharges it back into the mixing tube 4 through the mixing output channel, ensuring thorough mixing of the standard solution and the diluent. The specific operation of step S131 is as follows: the control unit controls the multi-channel valve 1 to switch to the mixing output channel, connecting the common port of the multi-channel valve 1 to the distribution port connected to the mixing tube 4. Subsequently, the syringe pump 2 draws more than two-thirds of the total volume of the mixture from the mixing tube 4 into the pump chamber, and then discharges the mixture from the pump chamber back into the mixing tube 4 through the mixing output channel. This suction and discharge mixing operation can be repeated multiple times, for example, 3 to 5 times, until the standard solution and the diluent reach a uniform concentration in the mixing tube 4. This repeated suction and discharge mixing method eliminates the need for a stir bar or magnetic stirrer in the mixing tube 4; efficient mixing can be achieved solely through the suction and discharge action of the syringe pump 2, simplifying the equipment structure and reducing manufacturing costs.

[0038] Then, step S14 is performed: Steps S11 to S13 and the optional step S131 are repeated to prepare a series of standard curve points with different concentrations by changing the ratio of the first volume to the second volume. For example, for a five-point standard curve, the dilution factors can be set to 1x, 2x, 5x, 10x, and 20x, respectively. The device prepares the standard solution for each concentration point sequentially and stores it in the mixing tube 4 for subsequent sample injection and detection. After preparing the standard solution for each concentration point, the tubing can be purged and cleaned as needed to prevent cross-contamination between different concentration points. The entire preparation process is automatically controlled by the control unit and requires no manual intervention.

[0039] In the sample injection analysis process S2, the first step S21 is performed: the three-way solenoid valve 3 is switched to the first working state, connecting the sample injection line of the analyzer to the mixing tube 4 through the three-way solenoid valve 3. The specific operation of step S21 is as follows: the control unit sends a switching signal to the three-way solenoid valve 3, and the valve core of the three-way solenoid valve 3 is driven by electromagnetic force to open the flow path between its first and third ports and close the flow path between its second and third ports. At this time, the sample injection line of the analyzer is connected to the mixing tube 4 through the first and third ports of the three-way solenoid valve 3, and the prepared standard solution in the mixing tube 4 can be drawn into the analyzer through the sample injection line.

[0040] Then, step S22 is performed: the analytical instrument draws the prepared standard solution from mixing tube 4 for detection. The analytical instrument can be any type of instrument, such as an inductively coupled plasma mass spectrometer, an inductively coupled plasma atomic emission spectrometer, an atomic absorption spectrometer, an atomic fluorescence spectrometer, or an ion chromatograph. The analytical instrument measures the standard solution at each concentration point according to a preset detection method, obtaining the corresponding signal intensity, which is used to establish a concentration-signal intensity standard curve.

[0041] In the cleaning pipeline process S3, the first step is S31: the three-way solenoid valve 3 is switched to the second working state, connecting the cleaning fluid source to the sample injection line of the analytical instrument through the three-way solenoid valve 3. The specific operation of step S31 is as follows: the control unit sends a switching signal to the three-way solenoid valve 3, and the valve core of the three-way solenoid valve 3 moves in the opposite direction under the drive of electromagnetic force, opening the flow path between its second and third ports and closing the flow path between its first and third ports. At this time, the cleaning fluid source is connected to the sample injection line of the analytical instrument through the second and third ports of the three-way solenoid valve 3.

[0042] Then, step S32 is performed: the cleaning solution flows into the sample injection line of the analyzer to clean it. Under the influence of gravity or the peristaltic pump of the analyzer's sample injection system, the cleaning solution flows from the cleaning solution source into the analyzer's sample injection line through the second and third ports of the three-way solenoid valve 3, rinsing away any residual standard solution or sample in the line to prevent cross-contamination from affecting the detection results of the next sample. After cleaning, the three-way solenoid valve 3 can be switched back to its first operating state to continue the next round of sample injection analysis. This simple switching between the two operating states of the three-way solenoid valve 3 enables rapid conversion between standard preparation and sample injection / cleaning modes without the need for manual tubing disconnection.

[0043] In one embodiment of this application, a high-concentration sample dilution step S4 is further included. When the concentration of the sample to be tested exceeds the linear range of the standard curve, the sample needs to be diluted before injection for detection. The high-concentration sample dilution step S4 includes the following sub-steps: Step S41: Switch the multi-channel valve 1 to the high-concentration sample channel, and the syringe pump 2 draws the first volume of high-concentration sample. The high-concentration sample channel is one of the distribution ports of the multi-channel valve 1, which is connected to the high-concentration sample source through a tubing. The specific operation process of step S41 is similar to that of step S11, except that the multi-channel valve 1 is switched to the high-concentration sample channel instead of the standard solution channel.

[0044] Step S42: Switch the multi-channel valve 1 to the diluent channel, and the syringe pump 2 draws in the second volume of diluent. The second volume is determined according to the target dilution factor. The higher the dilution factor, the larger the proportion of the second volume to the first volume. The specific operation process of step S42 is the same as that of step S12.

[0045] Step S43: The syringe pump 2 pumps the aspirated high-concentration sample and diluent together into the mixing tube 4. The high-concentration sample and diluent mix in the mixing tube 4 to form a diluted sample solution. The specific operation process of step S43 is the same as that of step S13. Preferably, the repeated aspiration and dispensing mixing operation in the aforementioned mixing step S131 can also be performed to ensure that the sample and diluent are fully mixed.

[0046] Step S44: The three-way solenoid valve 3 switches to the first working state, and the analytical instrument draws the diluted sample solution from the mixing tube 4 for detection. The specific operation process of step S44 is the same as that of steps S21 and S22. Through the above steps, high-concentration samples can be automatically diluted online to the linear range of the standard curve without the need for manual pre-dilution.

[0047] In one embodiment of this application, a pipeline purging step is also included. The pipeline purging step is used to remove residual liquid and air bubbles from the pipeline and mixing tube 4 to ensure labeling accuracy and detection stability. The pipeline purging step can be performed after each round of labeling, before changing the standard solution or sample, and during daily equipment maintenance. The pipeline purging process includes the following sub-steps: First, switch the multi-channel valve 1 to the air channel, and the syringe pump 2 draws in air. A needle filter is installed at the end of the air channel pipeline. The filter membrane inside the needle filter can effectively filter particulate matter in the air, preventing particulate matter from entering the flow path system and causing blockage or contamination. Second, switch the multi-channel valve 1 to the mixing output channel, and the syringe pump 2 discharges the drawn air into the mixing tube 4. After the air enters the mixing tube 4, it forms bubbles. During the rising process, the bubbles cause disturbance to the residual liquid in the mixing tube 4. At the same time, the impact force generated when the bubbles burst helps to peel off the droplets attached to the tube wall, achieving effective purging of the mixing tube 4 and the inside of the pipeline. Finally, switch the multi-channel valve 1 to the waste liquid channel, and the syringe pump 2 discharges the residual liquid and bubbles in the mixing tube 4 through the waste liquid channel. The waste liquid channel is connected to the waste liquid collection container to collect the waste liquid generated during cleaning and purging.

[0048] The device of this invention has strong scalability, requires minimal hardware modifications, and can be reused across multiple detection fields. Its basic function is to prepare inductively coupled plasma metal standard curves. Based on this, it can be further extended to environmental monitoring, completing automatic pre-dilution of water samples, preparation of matrix matching solutions, and preparation of spiked quality control samples, adapting to heavy metal speciation analysis. The device can interface with various analytical instruments such as atomic absorption spectrometers, atomic fluorescence spectrometers, and ion chromatographs, realizing online automatic addition of internal standards and automatic proportioning of eluents and reducing agents. After replacing the flow path pipes with materials suitable for organic solvents, it can be used in organic analysis scenarios such as food pesticide residue detection and serial port controllable characteristics. Leveraging the device's miniaturization and serial port controllability, it can be integrated into industrial online monitoring cabinets to achieve in-situ automatic dilution of samples such as electroplating wastewater and sewage wastewater, as well as automatic instrument calibration. With minor upgrades to the valve assembly, such as adding a multi-channel valve and a reservoir ring, two-stage ultra-high-rate dilution can be achieved; with the addition of a constant-temperature pipeline, it can adapt to the preparation requirements of easily crystallizing standard solutions. In addition, it can also prepare titrants, colorimetric reagents, and other commonly used laboratory reagents in batches. The entire system combines offline solution preparation and online co-processing modes with a single fluid handling unit, significantly reducing the cost of purchasing multiple devices in laboratories and minimizing human error. It can be widely used in various scenarios such as third-party testing laboratories, research institute laboratories, and industrial online monitoring.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An automatic dilution and labeling device, characterized in that, include: A multi-channel valve (1) has a common port and multiple distribution ports, the multiple distribution ports including a standard solution channel for connecting to a standard solution source, a diluent channel for connecting to a diluent source, a cleaning solution channel for connecting to a cleaning solution source, and an air distribution port, the air distribution port being connected to an air line; The syringe pump (2) is connected to the common port of the multi-channel valve (1) via a pipeline for quantitatively drawing and discharging liquid; The mixing tube (4) is used to receive and mix the standard solution and diluent discharged by the injection pump (2); The three-way solenoid valve (3) has a first port, a second port and a third port. The first port is used to connect to the sample injection line of the analytical instrument, the second port is used to connect to the cleaning liquid source, and the third port is connected to the mixing tube (4). The three-way solenoid valve (3) has a first working state and a second working state. In the first working state, the first port and the third port are connected, so that the sample injection line of the analytical instrument is connected to the mixing tube (4) for sample injection analysis. In the second working state, the second port and the third port are connected, so that the cleaning solution source is connected to the sample injection line of the analytical instrument for line cleaning; A needle filter is provided at the end of the air pipeline. The injection pump (2) draws in air filtered by the needle filter through the common port of the multi-channel valve (1) and the air distribution port, and discharges the air into the mixing pipe (4).

2. The automatic dilution and labeling device according to claim 1, characterized in that, The multi-channel valve (1) is a twelve-channel valve. The common port of the twelve-channel valve is connected to the inlet of the injection pump (2). The twelve distribution ports of the twelve-channel valve are respectively connected to the standard solution channel, diluent channel, cleaning solution channel, air channel, mixing output channel and waste liquid channel.

3. The automatic dilution and labeling device according to claim 1, characterized in that, A mixing output channel is provided on the pipeline between the mixing tube (4) and the third port of the three-way solenoid valve (3). The mixing output channel is connected to one distribution port of the multi-channel valve (1). The injection pump (2) draws the mixture from the mixing tube (4) through the multi-channel valve (1) and discharges the mixture back into the mixing tube (4) through the mixing output channel to achieve repeated mixing.

4. The automatic dilution and labeling device according to claim 3, characterized in that, The volume of the mixture drawn by the injection pump (2) from the mixing tube (4) through the multi-channel valve (1) is more than two-thirds of the total volume of the mixture in the mixing tube (4).

5. The automatic dilution and labeling device according to claim 1, characterized in that, The injection pump (2) is a plunger-type injection pump driven by a stepper motor. The pump body of the injection pump (2) is made of ceramic material, and the flow path pipes in the device are made of all PFA material.

6. The automatic dilution and labeling device according to claim 1, characterized in that, It also includes a device housing (5) and a control unit. The multi-channel valve (1), the injection pump (2), the three-way solenoid valve (3) and the mixing tube (4) are all integrated and installed inside the device housing (5). The control unit is electrically connected to the injection pump (2), the multi-channel valve (1) and the three-way solenoid valve (3). The control unit is configured to calculate the standard solution aspiration volume and the diluent aspiration volume according to the input dilution factor and the fixed volume, and control the injection pump (2) and the multi-channel valve (1) to complete the standard solution aspiration, diluent aspiration, mixed solution discharge and mixing operations in sequence.

7. The automatic dilution and labeling device according to claim 1, characterized in that, One distribution port of the multi-channel valve (1) is a matrix matching liquid channel, and the other distribution port is a spiking liquid channel. The matrix matching liquid channel and the spiking liquid channel are respectively connected to the corresponding reagent sources.

8. The automatic dilution and labeling device according to claim 1, characterized in that, The outer wall of the mixing tube (4) is provided with a constant temperature heating device, which is used to control the temperature of the liquid in the mixing tube (4).

9. An automatic dilution and labeling method, implemented using the automatic dilution and labeling device according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1: Prepare the standard curve, including the following sub-steps: S11: Switch the multi-channel valve (1) to the standard solution channel, and the syringe pump (2) draws the first volume of standard solution; S12: Switch the multi-channel valve (1) to the diluent channel, and the syringe pump (2) draws a second volume of diluent; S13: The syringe pump (2) pumps the aspirated standard solution and diluent into the mixing tube (4), where the standard solution and diluent are mixed to form the first concentration standard solution. S14: Repeat steps S11 to S13, and by changing the ratio of the first volume to the second volume, prepare a series of standard curve points with different concentrations. S2: Sample injection analysis, including the following sub-steps: S21: The three-way solenoid valve (3) is switched to the first working state, so that the sample injection line of the analyzer is connected to the mixing tube (4) through the three-way solenoid valve (3); S22: The analytical instrument draws the prepared standard solution from the mixing tube (4) for testing; S3: Clean the pipeline, including the following sub-steps: S31: The three-way solenoid valve (3) is switched to the second working state, so that the cleaning liquid source is connected to the sample injection line of the analyzer through the three-way solenoid valve (3); S32: The cleaning solution flows into the sample inlet line of the analyzer to clean the sample inlet line.

10. The automatic dilution and labeling method according to claim 9, characterized in that, Step S13 is followed by a mixing step S131: Switch the multi-channel valve (1) to the mixing output channel. The syringe pump (2) draws more than two-thirds of the volume of the mixed liquid from the mixing tube (4) and then discharges it back into the mixing tube (4) through the mixing output channel, so that the standard solution and the diluent are fully mixed.

11. The automatic dilution and labeling method according to claim 9, characterized in that, It also includes a high-concentration sample dilution step S4: S41: Switch the multi-channel valve (1) to the high-concentration sample channel, and the syringe pump (2) draws the first volume of high-concentration sample; S42: Switch the multi-channel valve (1) to the diluent channel, and the syringe pump (2) draws a second volume of diluent; S43: The syringe pump (2) pumps the high-concentration sample and diluent together into the mixing tube (4). The high-concentration sample and diluent are mixed in the mixing tube (4) to form a diluted sample solution. S44: The three-way solenoid valve (3) is switched to the first working state, and the analytical instrument draws the diluted sample solution from the mixing tube (4) for detection.

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