A fully automated method for the separation of radionuclides by solid phase extraction

Abstract

The application relates to a full-automatic nuclide separation solid-phase extraction method, and belongs to the technical field of nuclide separation. The method selects a required reagent solution through a multi-way electromagnetic valve, and precisely controls the suction volume of the reagent and the flow rate of the reagent through a chromatographic column through a syringe pump. When elements in a sample solution are separated and purified, the reagent is first sucked into a buffer tube connected with the syringe pump, then the chromatographic column channel is selected through the multi-way electromagnetic valve, and the liquid in the buffer tube is pushed through the chromatographic column and then flows into a collection bottle. For column passing of the sample solution, the channel of the sample solution bottle and the syringe pump in the multi-way electromagnetic valve is connected, and the air sucked in the syringe pump is directly pushed into the sample solution bottle at a certain speed, and the formed positive pressure slowly passes the sample solution through the chromatographic column at a certain flow rate. The method provided by the application can analyze Pu, Np, Sr, Am and other nuclides in water samples, solid and biological sample leaching solutions, and the extraction is precise and has no cross contamination.

Description

Technical Field

[0001] This invention belongs to the field of radionuclide separation equipment technology, specifically a fully automated solid-phase extraction method for radionuclide separation. Background Technology

[0002] Radionuclides are key radionuclides of concern in environmental and effluent monitoring. Therefore, in accordance with relevant standards and regulations, all environmental monitoring stations and nuclear power plants are required to conduct regular monitoring of these key radionuclides. Sample pretreatment involves separating and purifying the target radionuclide from the sample matrix, followed by qualitative or quantitative analysis using various analytical instruments. Current methods for radionuclide sample pretreatment are mostly manual, requiring multiple manual reagent additions and separation equipment operations—cumbersome steps, especially for high-activity samples. Manual operation may pose unnecessary radiation hazards to analysts and fails to address the urgent need for analyzing a large number of radionuclides in samples from the nuclear industry. Automated solid-phase extraction (SPE) instruments have emerged to meet this market demand.

[0003] Solid-phase extraction (SPE) is a sample pretreatment technique developed by combining liquid-solid extraction columns and liquid chromatography. It is primarily used for the separation, purification, and enrichment of specific nuclides in samples, reducing interference from the sample matrix on the instrument during measurement, and improving detection sensitivity. SPE involves steps such as activation, sample loading, rinsing, and elution, and is often complex to perform.

[0004] While automated solid-phase extraction (SPE) instruments, both domestically and internationally, employ different methods for SPE, they all share some common drawbacks. Some instruments use peristaltic pumps to control sample injection speed and liquid volume, which easily introduces air bubbles into the liquid path, resulting in low precision and poor repeatability in liquid volume and delivery speed control. Furthermore, the flexible tubing used in these instruments has a narrow speed range and requires frequent replacement to prevent aging and shedding. Since the sample solution and all reagents must pass through the same tubing, cross-contamination between different samples can occur if the tubing is not replaced each time. Although flow syringe pumps, with their more precise speed control, are widely used, instruments currently on the market using flow syringe pumps have not yet fully resolved the issues of background control and cross-contamination in the analysis of low-content samples. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a fully automated solid-phase extraction method for radionuclide separation. This method can analyze radionuclides such as Pu, Np, Sr, and Am in water samples, solid samples, and biological sample extracts, and has high extraction efficiency, fast speed, and no cross-contamination of target radionuclides.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A fully automated solid-phase extraction method for radionuclide separation is disclosed. The method is implemented using a fully automated solid-phase extraction instrument for radionuclide separation. The instrument includes a main controller and multiple channel modules. Each channel module includes a multi-port solenoid valve, a syringe pump, a chromatography column, a precision motor guide rail, and a Y-axis robotic arm. The multi-port solenoid valve has multiple channels, designated as a first channel, a second channel, ..., a Nth channel. The first channel is connected to the syringe pump, and a buffer tube is installed on the pipeline connecting the first channel and the syringe pump. The second channel is connected to the inlet of a sample bottle, which contains a hydrophilic sieve plate. The third channel is connected to the inlet of the chromatography column. The remaining channels are connected to the first reagent bottle, the second reagent bottle, ..., the Nth reagent bottle, respectively. The front end of the syringe pump is equipped with a three-way valve head, and the three ports of the three-way valve head are connected to the syringe pump, the air tube, and the first channel of the multi-way solenoid valve, respectively. The inlet end of the chromatography column is connected to a three-way valve, and the two inlet ends of the three-way valve are connected to the third channel of the multi-way solenoid valve and the outlet end of the sample bottle, respectively. A tray is provided on the precision motor guide rail, and multiple collection bottles for collecting the effluent from each step of the chromatography column are arranged at intervals on the tray. The Y-axis robotic arm is connected to the chromatography column and is used to control the vertical movement of the chromatography column.

[0008] The method includes the following steps:

[0009] S1. The required volume of the first reagent solution is drawn into the buffer tube through the multi-port solenoid valve and the syringe pump. Then, the syringe pump is connected to the chromatography column through the multi-port solenoid valve. The first reagent solution in the buffer tube is pushed through the chromatography column at a first set flow rate. The effluent is collected in the first collection bottle.

[0010] S2. Connect the injection pump to the sample bottle through the multi-port solenoid valve, and pass the sample solution in the sample bottle through the chromatography column at a second set flow rate. The eluent is collected in the second collection bottle.

[0011] S3. The required volume of the first reagent solution is drawn into the buffer tube through the multi-port solenoid valve and the syringe pump. Then the first reagent solution is delivered to the sample bottle and then completely passed through the chromatography column at the third set flow rate. The eluent is collected in the third collection bottle.

[0012] S4. Following the method in step S1, sequentially draw the required volumes of the second reagent solution, the third reagent solution, ... the Nth reagent solution into the buffer tube. Then, select the chromatography column channel through the multi-port solenoid valve and push the reagent solution in the buffer tube through the chromatography column at the set flow rate for each step. Collect the effluent from each step separately in a new collection bottle.

[0013] Furthermore, in the fully automated radionuclide separation solid-phase extraction method described above, step S1 specifically comprises:

[0014] S11. The precision motor guide rail drives the tray to move, and moves the first collection bottle horizontally to directly below the chromatography column, and lowers the outlet of the chromatography column below the mouth of the first collection bottle.

[0015] S12. Connect the syringe pump to the first reagent bottle through a multi-port solenoid valve, and the syringe pump accurately draws the required volume of the first reagent solution into the buffer tube connected to the syringe pump.

[0016] S13. The syringe pump is switched to the air tube channel to extract a first quantitative volume of air, which is the volume of the empty tube between the third channel of the multi-port solenoid valve and the chromatography column.

[0017] S14. Connect the syringe pump to the chromatography column through a multi-port solenoid valve. First, push out the quantitative volume of air through the syringe pump to quickly push the first reagent solution in the buffer tube to the top of the chromatography column.

[0018] S15. The first reagent solution is pushed out by the syringe pump at the first set flow rate, so that the first reagent solution completely passes through the chromatography column at the first set flow rate, and the eluent is collected in the first collection bottle.

[0019] S16, the Y-axis robotic arm raises the outlet of the chromatography column above the mouth of the first collection bottle.

[0020] Furthermore, the fully automated radionuclide separation solid-phase extraction method described above further includes the following after step S15:

[0021] After the first reagent solution has completely flowed through the chromatography column and the syringe pump has reached the zero position, the syringe pump switches to the air channel to draw in the first set volume of air. Then, the syringe pump is connected to the chromatography column through the multi-port solenoid valve, and the syringe pump injects the first volume of air into the chromatography column to empty the reagent solution in the tubing and the chromatography column.

[0022] Furthermore, in the fully automated radionuclide separation solid-phase extraction method described above, step S2 specifically comprises:

[0023] S21. The precision motor guide rail drives the tray to move, and moves the second collection bottle horizontally to directly below the chromatography column, and lowers the outlet of the chromatography column below the mouth of the second collection bottle.

[0024] S22. The syringe pump is connected to the air tube to draw a second set volume of air. Then, the syringe pump is connected to the sample bottle through the multi-port solenoid valve. The syringe pump pushes the second volume of air into the sample bottle at a second set flow rate. The positive pressure formed causes the sample solution in the sample bottle to pass through the chromatography column at the second set flow rate. The effluent is collected in the second collection bottle.

[0025] S23, the Y-axis robotic arm raises the outlet of the chromatography column above the mouth of the second collection bottle.

[0026] Furthermore, the fully automated radionuclide separation solid-phase extraction method described above further includes the following after step S22:

[0027] After all the liquid has flowed through the chromatography column and the syringe pump has reached zero, the syringe pump switches to the air channel to draw in a third set volume of air. Then, the syringe pump is connected to the sample bottle through a multi-port solenoid valve. The syringe pump then pumps the third set volume of air into the sample bottle, emptying the sample solution in the sample bottle and the chromatography column.

[0028] Furthermore, in the fully automated radionuclide separation solid-phase extraction method described above, step S3 specifically comprises:

[0029] S31. Move the tray horizontally to directly below the chromatography column, and lower the outlet of the chromatography column below the mouth of the third collection bottle.

[0030] S32. Connect the syringe pump to the first reagent bottle through a multi-port solenoid valve, and the syringe pump accurately draws the required volume of the first reagent solution into the buffer tube.

[0031] S33. The syringe pump is switched to the air tube channel to draw a second quantitative volume of air, which is the volume of the empty tube between the second channel of the multi-way solenoid valve and the chromatography column.

[0032] S34. Connect the syringe pump to the sample bottle through a multi-port solenoid valve. Use the syringe pump to push air to deliver the first reagent solution in the buffer tube to the sample bottle. Then, use the syringe pump to push the first reagent solution through the chromatography column at a third set flow rate. The eluent is collected in the third collection bottle.

[0033] S35, the Y-axis robotic arm raises the outlet of the chromatography column above the mouth of the third collection bottle.

[0034] Furthermore, in the fully automated radionuclide separation solid-phase extraction method described above, step S34 further includes:

[0035] After all the liquid has flowed through the chromatography column and the syringe pump has reached zero, the syringe pump switches to the air channel to draw the third set volume of air. Then, the syringe pump is connected to the sample bottle through the multi-port solenoid valve, and the syringe pump injects the third set volume of air into the sample bottle, emptying the sample solution in the sample bottle and the chromatography column.

[0036] Furthermore, in the fully automated radionuclide separation solid-phase extraction method described above, after the effluent from each step is collected, the air tube and buffer tube in the three-way valve head at the front end of the injection pump are connected to restore the pressure in the entire system to atmospheric pressure.

[0037] Furthermore, in the fully automated solid-phase extraction method for radionuclide separation described above, the volumes of the first set volume of air, the second set volume of air, and the third set volume of air range from 5 to 200 mL.

[0038] Furthermore, in the fully automated solid-phase extraction method for radionuclide separation described above, the set flow rate range for the reagent solution passing through the chromatography column is 0.5-5 mL / min; the set flow rate range for the sample solution passing through the chromatography column is 0.5-3 mL / min.

[0039] The fully automated radionuclide separation solid-phase extraction method described in this invention has the following significant technical advantages:

[0040] 1. This invention solves the problem of cross-contamination between samples in existing fully automated solid-phase extraction methods on the market. After analyzing high-content target nuclides, there is almost no residue, and the decontamination factor for the target nuclides is >3.3×10⁻⁶. 4 For low-content samples, the experimental results are more accurate and scientific;

[0041] 2. This invention can automatically complete the processes of column pretreatment, sample loading, and column washing, thus realizing automated analysis and extraction.

[0042] 3. This invention incorporates a specially designed sieve plate in the sample bottle to filter large particles, effectively preventing clogging of the chromatography column by particulate matter in the sample solution. The separate design of the sample solution channel and reagent washing channel ensures that even if the sample bottle is clogged by large particles and the sample cannot be completely drained, it does not affect the subsequent washing of the chromatography column by the elution solution; only the recovery rate decreases. Even when the content of the target nuclide is higher than the instrument's detection limit, effective and reliable experimental data can still be obtained, ensuring the acquisition of analytical data for valuable samples with small sample volumes.

[0043] 4. The present invention employs a method of extracting a large amount of air and injecting it through the liquid path after each liquid feed through the column, so as to completely empty the solution remaining in the pipeline and the chromatography column, thereby avoiding cross-contamination between different steps caused by the solution residue and reducing the volume of the solution to be washed in the next step.

[0044] 5. After each liquid dispensing and delivery operation is completed, the pipeline system is connected to the atmosphere to restore the gas pressure in the pipeline to atmospheric pressure level, ensuring the accuracy of the liquid volume and liquid flow rate in the next step. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the liquid circuit connection of a channel module of a fully automated radionuclide separation solid phase extraction instrument provided in an embodiment of the present invention;

[0046] Figure 2This is a flowchart of a fully automated solid-phase extraction method for radionuclide separation provided in an embodiment of the present invention;

[0047] Figure 3 for Figure 2 The flowchart of step S1 in the method;

[0048] Figure 4 for Figure 2 The flowchart of step S2 in the method;

[0049] Figure 5 for Figure 2 The flowchart of step S3 in the method;

[0050] Figure 1 In the middle: 1-Multi-port solenoid valve, 2-Injection pump, 3-Reagent bottle, 4-Sample bottle, 5-Chromatography column, 6-Collection bottle, 7-Buffer tube, 8-T-way valve, 9-First one-way valve, 10-Second one-way valve, 11-Switch valve; 101-First channel, 102-Second channel, 103-Third channel, 104-Fourth channel, 105-Fifth channel, 106-Sixth channel, 107-Seventh channel. Detailed Implementation

[0051] The present invention will now be further described with reference to specific embodiments and the accompanying drawings.

[0052] This invention provides a fully automated solid-phase extraction method for radionuclide separation. The method is implemented using a fully automated solid-phase extraction instrument, which includes a main controller and multiple channel modules. Figure 1 The diagram shows the liquid circuit connection of one of the channel modules of the solid phase extraction instrument. Each channel module mainly includes a multi-way solenoid valve 1 and a syringe pump 2. The multi-way solenoid valve 1 has multiple channels, namely the first channel 101, the second channel 102, ... the Nth channel. The first channel 101 serves as a common channel and is connected to the syringe pump 2 of the corresponding channel module. The second channel 102 is connected to the inlet end of the sample bottle 4. The third channel 103 is connected to the inlet end of the chromatography column 5. The remaining channels are connected to multiple reagent bottles 3 respectively. The syringe pump 2 has a three-way valve head at the front end, which has a port a, a port b, and a port c. The port a is connected to the syringe pump. The ports b and c are connected to the air tube and the first channel of the multi-way solenoid valve 1, respectively. The inlet end of the chromatography column 5 is connected to a three-way valve 8. The two inlet ends of the three-way valve 8 are connected to the third channel of the multi-way solenoid valve 1 and the outlet end of the sample bottle 4, respectively. The collection bottle 6 is located directly below the chromatography column 5 and is used to collect the effluent from the chromatography column 5.

[0053] A buffer tube 7 is installed on the pipeline connecting the first channel of the multi-way solenoid valve 1 and the syringe pump 2 to prevent reagents from flowing into the syringe pump 2 and thus affecting the accuracy and lifespan of the syringe pump 2. At the same time, it eliminates the problem of cross-contamination between reagents caused by the residue of solution in the rubber stopper of the syringe pump.

[0054] The number of reagent bottles 3 and multi-port solenoid valve channels depends on the types of washing and elution solutions required for the separation and purification process. For ease of understanding, the reagent solutions are named as Reagent 1, Reagent 2, Reagent 3, ... Reagent N according to the order of use in the separation and purification process, and the corresponding reagent bottles are Reagent 1 Bottle, Reagent 2 Bottle, Reagent 3 Bottle, ... Reagent N Bottle; N+2 collection bottles are required.

[0055] Sample bottle 4 contains a sieve plate, which is a hydrophilic sieve plate with a pore size of <30μm.

[0056] Each channel module also includes a precision motor guide rail with a tray fixed on it. Multiple collection bottles 6 are installed in the tray for horizontal movement of the collection bottles 6. After each step of solution collection, the precision motor guide rail moves the tray horizontally a set distance, moving the new collection bottle directly below the chromatography column for easy collection of the next step's effluent. For the effluent flowing through the chromatography column in each step of the experiment, the collection bottles in the tray are moved sequentially to the corresponding step by the precision motor guide rail, allowing for individual collection of the effluent from each step.

[0057] Each channel module also includes a Y-axis robotic arm and a longitudinal motor. The Y-axis robotic arm is connected to the chromatography column 5 and is used to control the vertical movement of the chromatography column 5. Before each step begins, the Y-axis robotic arm lowers the outlet of the chromatography column below the mouth of the collection bottle to prevent splashing of the effluent during discharge and cross-contamination between the instrument and the sample. After each column pass step is completed, the Y-axis robotic arm raises the chromatography column to a position above the mouth of the collection bottle.

[0058] A first one-way valve 9 is installed on the pipeline connecting the three-way valve 8 and the third channel of the multi-way solenoid valve 1, and a second one-way valve 10 is installed on the pipeline connecting the three-way valve to the outlet end of the sample bottle. These two one-way valves are used to ensure that when the sample solution in the pipeline flows into the chromatography column through one of the two inlet ends of the selected three-way valve 8, it cannot flow back to the multi-way solenoid valve 1 through the other inlet end of the three-way valve 8.

[0059] A switch valve 11 is also installed on the pipeline between the outlet end of sample bottle 4 and the second one-way valve 10 to facilitate the control of sample solution loading. Before use, the new sample bottle 4 and switch valve 11 are connected but not installed on the instrument. Close switch valve 11, add sample solution to the new sample bottle 4, and then install this part on the instrument and open switch valve 11.

[0060] The tubing from the sample vial to the chromatography column uses a quick-connect, easily replaceable design. Before each experiment, a new sample vial, switch valve, second check valve, tee, chromatography column, collection bottle, and connecting tubing must be installed. The quick-connect design facilitates replacement before each experiment, ensuring that each sample is replaced individually, thus completely eliminating the possibility of cross-contamination between samples from a physical structural perspective.

[0061] The highest point of the liquid level in sample bottle 4 is lower than the lowest point of the chromatography column 5. This utilizes the principle of communicating vessels to ensure that the sample solution cannot flow through the column 5 on its own. Only when the gas pressure in the sample bottle is increased can the sample solution be forced through the resin column in chromatography column 5. This design requires no expensive electronic components and, after the sample solution is installed, can fully automate the entire experimental process, including resin column pretreatment, feed loading, and solution washing of the resin column.

[0062] In terms of electrical control, each channel module is distinguished by a hardware address to achieve independent control. The hardware data control electrical interface adopts a bus-based control method, simplifying hardware connections and reducing control interfaces and cable connections in complex multi-hardware control environments. In terms of hardware, the main control components for each channel are a multi-port solenoid valve 1 and a syringe pump 2. Each channel's multi-port solenoid valve 1 and syringe pump 2 are controlled using different bus control interfaces. Communication cables for identical components in each channel are connected in parallel, and the two control groups for multi-port solenoid valve 1 and syringe pump 2 are sequentially set to different IDs via hardware addresses. This allows for simultaneous setting of multiple channels in hardware control while enabling the flexibility of independent control of each channel through different ID settings. Software control distinguishes each independent channel by using the ID byte in the communication protocol. Each channel uses different commands to switch multi-port solenoid valve 1 and control the movement of syringe pump 2. Before the experiment, the operator sets the number of channels to be run. Upon receiving this command, the main controller automatically determines the total number of channels to be run in the experiment and executes commands for each experimental procedure based on the ID of the channel to be run. The problem of precise control of multi-channel solution column volume can be solved by making the tubing of different channels in the same step equal in length.

[0063] Based on the aforementioned fully automated radionuclide separation solid-phase extraction instrument, this invention provides a fully automated radionuclide separation solid-phase extraction method. Figure 2 A flowchart of the method is shown, including the following steps:

[0064] S1. The required volume of the first reagent solution is drawn into the buffer tube through a multi-way solenoid valve and a syringe pump. Then, the syringe pump is connected to the chromatography column through the multi-way solenoid valve, and the first reagent solution in the buffer tube is pushed through the chromatography column at a first set flow rate. The eluent is collected in the first collection bottle.

[0065] This step specifically includes the following procedures:

[0066] S11. The precision motor guide rail drives the tray to move, and moves the first collection bottle horizontally to directly below the chromatography column, and lowers the outlet of the chromatography column below the mouth of the first collection bottle.

[0067] S12. Connect the syringe pump to the first reagent bottle through a multi-port solenoid valve, and the syringe pump accurately draws the required volume of the first reagent solution into the buffer tube connected to the syringe pump.

[0068] S13. The syringe pump is switched to the air tube channel to extract a first quantitative volume of air, which is the volume of the empty tube between the third channel of the multi-port solenoid valve and the chromatography column.

[0069] S14. Connect the syringe pump to the chromatography column through a multi-port solenoid valve. First, push out the quantitative volume of air through the syringe pump to quickly push the first reagent solution in the buffer tube to the top of the chromatography column.

[0070] S15. The first reagent solution is pushed out by a syringe pump at the first set flow rate, so that the first reagent solution completely passes through the chromatography column at the first set flow rate, and the eluent is collected in the first collection bottle.

[0071] After the first reagent solution has completely flowed through the chromatography column and the syringe pump has reached the zero position, the syringe pump switches to the air channel to draw a first set volume of air. Then, the syringe pump is connected to the chromatography column through the multi-port solenoid valve, and the syringe pump injects the first set volume of air into the chromatography column to empty the solution in the tubing and the chromatography column.

[0072] S16, the Y-axis robotic arm raises the outlet of the chromatography column above the mouth of the first collection bottle.

[0073] Then, connect port b of the three-way valve head at the front end of the injection pump to port c, so that the pressure in the entire pipeline is restored to atmospheric pressure.

[0074] S2. Connect the injection pump to the sample bottle through the multi-port solenoid valve, and pass the sample solution in the sample bottle through the chromatography column at a second set flow rate. The eluent is collected in the second collection bottle.

[0075] This step specifically includes the following procedures:

[0076] S21. The precision motor guide rail drives the tray to move, and moves the second collection bottle horizontally to directly below the chromatography column, and lowers the outlet of the chromatography column below the mouth of the second collection bottle.

[0077] S22. The syringe pump draws a second set volume of air through the air tube, and then connects the syringe pump to the sample bottle through the multi-port solenoid valve. The syringe pump pushes the second volume of air into the sample bottle at a second set flow rate. The positive pressure formed causes the sample solution in the sample bottle to pass through the chromatography column at the second set flow rate, and the effluent is collected in the second collection bottle.

[0078] If the sample solution in the sample vial does not completely pass through the chromatography column, repeat the above steps until the sample solution has completely passed through the chromatography column and the syringe pump returns to zero. After the sample solution has completely passed through the chromatography column, switch the syringe pump to the air channel to extract a third set volume of air. Then, connect the syringe pump to the sample vial through the multi-port solenoid valve. The syringe pump will then inject the third set volume of air into the sample vial, emptying the sample solution from both the sample vial and the chromatography column.

[0079] S23, the Y-axis robotic arm raises the outlet of the chromatography column above the mouth of the second collection bottle.

[0080] Then, connect port b of the three-way valve head at the front end of the injection pump to port c, so that the pressure in the entire pipeline is restored to atmospheric pressure.

[0081] S3. The required volume of the first reagent solution is drawn into the buffer tube through the multi-port solenoid valve and the syringe pump. Then, the first reagent solution is delivered to the sample bottle and completely passes through the chromatography column at the third set flow rate. The eluent is collected in the third collection bottle.

[0082] This step serves to wash away any residual sample solution in the sample bottle. The specific operation includes the following steps:

[0083] S31. Move the tray horizontally to directly below the chromatography column, and lower the outlet of the chromatography column below the mouth of the third collection bottle.

[0084] S32. Connect the syringe pump to the first reagent bottle through a multi-port solenoid valve, and the syringe pump accurately draws the required volume of the first reagent solution into the buffer tube connected to the syringe pump.

[0085] S33. The syringe pump is switched to the air tube channel to draw a second quantitative volume of air, which is the volume of the empty tube between the second channel of the multi-way solenoid valve and the chromatography column.

[0086] S34. Connect the syringe pump to the sample bottle through the multi-port solenoid valve. Use the syringe pump to push the air in the buffer tube to deliver the first reagent solution in the sample bottle. Then use the syringe pump to push the first reagent solution through the chromatography column at the third set flow rate. The eluent is collected in the third collection bottle.

[0087] After all the liquid has flowed through the chromatography column and the syringe pump has reached zero, the syringe pump switches to the air channel to draw in a third set volume of air. Then, the syringe pump is connected to the sample bottle through a multi-port solenoid valve. The syringe pump then pumps the third set volume of air into the sample bottle, emptying the sample solution in the sample bottle and the chromatography column.

[0088] The S35 Y-axis robotic arm raises the outlet of the chromatography column above the mouth of the third collection bottle.

[0089] Then, connect the air tube and buffer tube in the three-way valve head at the front end of the injection pump to restore the pressure in the entire pipeline to atmospheric pressure.

[0090] S4. Following the method in step S1, sequentially draw the required volumes of the second reagent solution, the third reagent solution, ... the Nth reagent solution into the buffer tube. Then, select the chromatography column channel through the multi-port solenoid valve and push the reagent solution in the buffer tube through the chromatography column at the set flow rate for each step. Collect the effluent from each step separately in a new collection bottle.

[0091] After the effluent from each step is collected, connect the air tube and buffer tube in the three-way valve head at the front end of the syringe pump to restore the pressure in the entire system to atmospheric pressure.

[0092] In this embodiment of the invention, the volumes of the first set volume of air, the second set volume of air, and the third set volume of air are in the range of 5-200 mL; the set flow rate of the reagent solution through the chromatography column is in the range of 0.5-5 mL / min; and the set speed of the sample solution through the chromatography column is in the range of 0.5-3 mL / min.

[0093] The following example uses the TEVA resin Pu separation method to illustrate the fully automated radionuclide separation solid-phase extraction method. In this example, the chromatography column is filled with TEVA resin, and the three reagent solutions and their volumes required for the radionuclide separation and purification process are as follows:

[0094] First reagent solution: 8M HNO3 + 0.02M NaNO2, volume: 10mL

[0095] Second reagent solution: 9M HCl, volume: 10mL

[0096] Third reagent solution: 0.1M HCl + 0.01M HF, volume: 10mL

[0097] The sample solution system consisted of 8 M HNO3 + 0.02 M NaNO2, with a volume of 15 mL.

[0098] The specific separation operation steps are as follows:

[0099] 1. Move the collection bottle tray and slowly move the position of the first collection bottle below the chromatography column, lowering the lower end of the chromatography column in the Y-axis direction below the mouth of the first collection bottle.

[0100] 2. The syringe pump's built-in valve selects channels a and c. The first channel of the multi-way solenoid valve is connected to the fourth channel. The syringe pump moves downward, drawing a set pretreatment volume of the first reagent solution into the buffer tube connected to the syringe pump. The syringe pump's built-in valve selects channels a and b, then draws the air volume from the third channel of the multi-way solenoid valve to the chromatography column. The first and third channels of the multi-way solenoid valve are connected, and the syringe pump's built-in valve switches to channel a and c. The syringe pump first pushes out this volume of air to deliver the liquid in the buffer tube to the top of the chromatography column. Then, this volume of air is passed through a preset flow... The solution in the buffer tube is pumped out at a flow rate of 1 mL / min, allowing it to pass completely through the chromatography column and be collected in the first collection bottle. After all the liquid has passed through the chromatography column and the syringe pump has reached zero, the syringe pump's built-in valve selects channels a and b to extract 5-50 mL of air. The syringe pump's built-in valve selects channels a and c, and this air is then injected into the chromatography column through the first and third channels of the multi-channel electromagnetic pump, emptying the solution from the tubing and the chromatography column. Finally, the syringe pump's built-in valve selects channels b and c to restore the pressure in the entire system to atmospheric pressure.

[0101] 3. Raise the lower end of the chromatography column above the opening of the first collection bottle in the Y-axis direction, move the collection bottle tray, slowly move the position of the second collection bottle below the chromatography column, and lower the lower end of the chromatography column below the opening of the second collection bottle in the Y-axis direction.

[0102] 4. Select channels a and b on the syringe pump's built-in valve head to extract 5-50 mL of air; select channels a and c on the syringe pump's built-in valve head. Connect the first and second channels of the multi-port solenoid valve. The syringe pump then pushes air into the sample bottle at a preset speed, using positive pressure to force the sample solution in the sample bottle through the chromatography column at a flow rate of 0.5 mL / min, and collects it in the second solution collection bottle. If the solution in the sample bottle does not completely pass through the chromatography column, repeat the above steps until the sample solution has completely passed through the chromatography column and the syringe pump returns to zero. After the solution has completely passed through the chromatography column, select channels a and b on the syringe pump's built-in valve head to extract 5-50 mL of air, select channels a and c on the syringe pump's built-in valve head, and inject this air into the sample bottle through the first and second channels of the multi-port solenoid valve, emptying the solution in the sample bottle and the chromatography column. Then, select channels b and c on the syringe pump's built-in valve head to restore the pressure in the entire system to atmospheric pressure.

[0103] 5. Raise the lower end of the chromatography column in the Y-axis direction above the mouth of the second collection bottle, move the collection bottle tray, slowly move the position of the third collection bottle below the chromatography column, and lower the lower end of the chromatography column in the Y-axis direction below the mouth of the third collection bottle.

[0104] 6. The syringe pump's built-in valve selects channels a and c. The first channel of the multi-way solenoid valve connects to the fourth channel. The syringe pump moves downward, drawing a set volume of the first reagent solution into the buffer tube connected to the syringe pump. The syringe pump's built-in valve selects channels a and b, then draws the empty tube volume of air between the second channel and the chromatography column. The first channel of the multi-way solenoid valve connects to the second channel, and the syringe pump's built-in valve switches to the a and c channels, using the syringe pump to push this portion of air to deliver the liquid in the buffer tube to the sample vial. Then, the reagent volume of air is pumped at a preset flow rate (1 mL). The solution in the buffer tube is pumped out at a flow rate of ( / min) to ensure that it completely passes through the chromatography column and is collected in the third collection bottle. After all the liquid has passed through the chromatography column and the syringe pump has reached zero, the syringe pump's built-in valve selects channels a and b to extract 5-50 mL of air. The syringe pump's built-in valve selects channels a and c and injects this air into the chromatography column through the first and second channels of the multi-channel electromagnetic system, emptying the solution in the tubing and the chromatography column. Then, the syringe pump's built-in valve selects channels b and c to restore the pressure in the entire system to atmospheric pressure.

[0105] 7. Raise the lower end of the chromatography column in the Y-axis direction above the mouth of the third collection bottle, move the collection bottle tray, slowly move the position of the fourth collection bottle below the chromatography column, and lower the lower end of the chromatography column in the Y-axis direction below the mouth of the fourth collection bottle.

[0106] 8. The syringe pump's built-in valve selects channels a and c. The first channel of the multi-way solenoid valve connects to the fifth channel. The syringe pump moves downward, drawing a set volume of the second reagent solution into the buffer tube connected to the syringe pump. The syringe pump's built-in valve selects channels a and b, then draws the empty tube volume of air between the third channel and the chromatography column. The first channel of the multi-way solenoid valve connects to the third channel, and the syringe pump's built-in valve switches to the a and c channels, using the syringe pump to push this portion of air to deliver the liquid in the buffer tube to the top of the chromatography column. Then, the reagent volume of air is maintained at a preset flow rate (0.5 m). The solution in the buffer tube is pumped out at a flow rate of L / min, allowing it to completely pass through the chromatography column and be collected in the fourth collection bottle. After all the liquid has passed through the chromatography column and the syringe pump has reached zero, the syringe pump's built-in valve selects channels a and b to extract 5-50 mL of air. The syringe pump's built-in valve selects channels a and c, and this air is injected into the chromatography column through the first and third channels of the multi-channel electromagnetic system, emptying the solution in the tubing and the chromatography column. Then, the syringe pump's built-in valve selects channels b and c to restore the pressure in the entire system to atmospheric pressure.

[0107] 9. Raise the lower end of the chromatography column in the Y-axis direction above the mouth of the fourth collection bottle, move the collection bottle tray, slowly move the position of the fifth collection bottle below the chromatography column, and lower the lower end of the chromatography column in the Y-axis direction below the mouth of the fifth collection bottle.

[0108] 10. The syringe pump's built-in valve selects channels a and c. The first channel of the multi-way solenoid valve connects to the sixth channel. The syringe pump moves downward, drawing a set volume of the third reagent solution into the buffer tube connected to the syringe pump. The syringe pump's built-in valve selects channels a and b, then draws the empty tube volume of air between the third channel and the chromatography column. The first channel of the multi-way solenoid valve connects to the third channel, and the syringe pump's built-in valve switches to the a and c channels, using the syringe pump to push this portion of air to deliver the liquid in the buffer tube to the top of the chromatography column. Then, the reagent volume of air is maintained at a preset flow rate (0.5). The solution in the buffer tube is pumped out at a flow rate of (mL / min) to ensure that it completely passes through the chromatography column and is collected in the fifth collection flask. After all the liquid has passed through the chromatography column and the syringe pump has reached zero, the syringe pump's built-in valve selects channels a and b to extract 5-50 mL of air. The syringe pump's built-in valve selects channels a and c and injects this air into the chromatography column through the first and third channels of the multi-channel electromagnetic system, emptying the solution in the tubing and the chromatography column. Then, the syringe pump's built-in valve selects channels b and c to restore the pressure in the entire system to atmospheric pressure.

[0109] 11. Raise the lower end of the chromatography column along the Y-axis to above the mouth of the fifth collection bottle to complete the entire process.

[0110] Experimental results verified using the above methods

[0111] I. Separation and purification efficiency and time of different nuclides

[0112] The procedures for separating and purifying radionuclides using different chromatography columns were set into the above workflow. The target nuclides in the samples were separated and purified using this workflow. The analytical methods and results are shown in Table 1. The results show that this workflow can stably and reliably analyze the target nuclides in the sample solution, with a recovery rate of over 90%. For each batch of 8 samples, including the time for solution preparation, tubing installation, and sample bottle setup, the batch sample separation and purification time is less than 3 hours.

[0113] Table 1. Flowcharts for separating and purifying target nuclides using different chromatography columns.

[0114]

[0115] II. Detection Limits of Different Nuclides

[0116] Different radionuclides were separated and purified using this instrument, and the content of radionuclides was measured using a triple tandem quadrupole inductively coupled plasma mass spectrometer (ICP-MS / MS), an alpha spectrometer, and a liquid scintillation counter. The detection limits of the target nuclides separated and purified by this automated instrument were obtained, and the results are shown in Table 2.

[0117] Table 2 Detection limits for different target nuclides

[0118]

[0119]

[0120] III. Decontamination Agents

[0121] To verify the effect of the instrument on the analysis of samples with low radionuclide content after analyzing samples with high radionuclide content, this experiment used the above-mentioned TEVA resin process to separate and purify samples containing 25.0 mBq (174.84 pg). 242 Pu water sample. After the instrument completes this procedure, replace all tubing, sample bottles, and the chromatography column from the second and third channels of the multi-port solenoid valve to the chromatography column. Then, perform the TEVA resin analysis procedure on the Pu blank sample and measure its concentration. 242 The content of Pu was determined. The results showed that: 239 The measured value of Pu was 0.0002 mBq (1.5 fg), indicating that the procedure established in this experiment left almost no residue after analyzing high-content target nuclides, and the decontamination factor for the target nuclides was >1.25 × 10⁻⁶. 5 This demonstrates that the procedure can analyze samples at extremely low levels.

[0122] This invention provides a fully automated solid-phase extraction method for radionuclide separation, which offers precise extraction without cross-contamination. The control system precisely controls the amount of solution added to the reagent bottle via a syringe pump, while simultaneously controlling the flow rates of the reagent solution and sample solution. The control system automatically compensates for resistance encountered during the transport of the reagent solution from the reagent bottle to the sample bottle and the chromatography column, ensuring the accuracy of the delivery of the washing and elution solutions. Utilizing the precise control and pressure monitoring capabilities of the syringe pump, the safety and reliability of the washing and elution solution delivery process are ensured. Furthermore, the control system is equipped with a peripheral interface for connection to a computer, enabling remote monitoring and control of the equipment.

[0123] The above embodiments are merely illustrative examples of the present invention. The present invention may also be implemented in other specific ways or forms without departing from its spirit or essential characteristics. Therefore, the described embodiments should be considered illustrative rather than limiting in any respect. The scope of the present invention should be defined by the appended claims, and any variations equivalent to the intent and scope of the claims should also be included within the scope of the present invention.

Claims

1. A fully automated solid-phase extraction method for radionuclide separation, the method being implemented using a fully automated solid-phase extraction instrument for radionuclide separation, the extraction instrument comprising a main controller and multiple channel modules, each channel module comprising a multi-port solenoid valve, an injection pump, a chromatography column, a precision motor guide rail, and a Y-axis robotic arm, wherein: The multi-port solenoid valve has multiple channels, namely a first channel, a second channel, ..., an Nth channel. The first channel is connected to the syringe pump, and a buffer tube is installed on the pipeline connecting the first channel and the syringe pump. The second channel is connected to the inlet end of the sample bottle, and the sample bottle contains a hydrophilic sieve plate. The third channel is connected to the inlet end of the chromatography column, and the remaining channels are connected to the first reagent bottle, the second reagent bottle, ..., the Nth reagent bottle, respectively. The syringe pump has a built-in three-way valve head, and the three ports of the three-way valve head are connected to the syringe pump, the air tube, and the first channel of the multi-port solenoid valve, respectively. The inlet end of the chromatography column is connected to a three-way valve, and the two inlet ends of the three-way valve are connected to the third channel of the multi-port solenoid valve and the outlet end of the sample bottle, respectively. A tray is provided on the precision motor guide rail, and multiple collection bottles for collecting the effluent from each step of the chromatography column are arranged at intervals on the tray. The Y-axis robotic arm is connected to the chromatography column and is used to control the vertical movement of the chromatography column. The method includes the following steps: S1. The required volume of the first reagent solution is drawn into the buffer tube through the multi-port solenoid valve and the syringe pump. Then, the syringe pump is connected to the chromatography column through the multi-port solenoid valve. The first reagent solution in the buffer tube is pushed through the chromatography column at a first set flow rate. The effluent is collected in the first collection bottle. S2. Connect the injection pump to the sample bottle through the multi-port solenoid valve, and pass the sample solution in the sample bottle through the chromatography column at a second set flow rate. The eluent is collected in the second collection bottle. S3. The required volume of the first reagent solution is drawn into the buffer tube through the multi-port solenoid valve and the syringe pump. Then the first reagent solution is delivered to the sample bottle and then completely passed through the chromatography column at the third set flow rate. The eluent is collected in the third collection bottle. S4. Following the method in step S1, sequentially draw the required volumes of the second reagent solution, the third reagent solution, ... the Nth reagent solution into the buffer tube. Then, select the chromatography column channel through the multi-port solenoid valve and push the reagent solution in the buffer tube through the chromatography column at the set flow rate for each step. Collect the effluent from each step separately in a new collection bottle.

2. The fully automated radionuclide separation solid-phase extraction method according to claim 1, characterized in that, Step S1 is as follows: S11. The precision motor guide rail drives the tray to move, and moves the first collection bottle horizontally to directly below the chromatography column, and lowers the outlet of the chromatography column below the mouth of the first collection bottle. S12. Connect the syringe pump to the first reagent bottle through a multi-port solenoid valve, and the syringe pump accurately draws the required volume of the first reagent solution into the buffer tube connected to the syringe pump. S13. The syringe pump is switched to the air tube channel to extract a first quantitative volume of air, which is the volume of the empty tube between the third channel of the multi-port solenoid valve and the chromatography column. S14. Connect the syringe pump to the chromatography column through a multi-port solenoid valve. First, push out the quantitative volume of air through the syringe pump to quickly push the first reagent solution in the buffer tube to the top of the chromatography column. S15. The first reagent solution is pushed out by the syringe pump at the first set flow rate, so that the first reagent solution completely passes through the chromatography column at the first set flow rate, and the eluent is collected in the first collection bottle. S16, the Y-axis robotic arm raises the outlet of the chromatography column above the mouth of the first collection bottle.

3. The fully automated radionuclide separation solid-phase extraction method according to claim 2, characterized in that, Step S15 is followed by: After the first reagent solution has completely flowed through the chromatography column and the syringe pump has reached the zero position, the syringe pump switches to the air channel to draw in the first set volume of air. Then, the syringe pump is connected to the chromatography column through the multi-port solenoid valve, and the syringe pump injects the first set volume of air into the chromatography column to empty the reagent solution in the tubing and the chromatography column.

4. The fully automated radionuclide separation solid-phase extraction method according to claim 3, characterized in that, Step S2 is as follows: S21. The precision motor guide rail drives the tray to move, and moves the second collection bottle horizontally to directly below the chromatography column, and lowers the outlet of the chromatography column below the mouth of the second collection bottle. S22. The syringe pump is connected to the air tube to draw in the second set volume of air. Then, the syringe pump is connected to the sample bottle through the multi-port solenoid valve. The syringe pump pushes the second set volume of air into the sample bottle at the second set flow rate. The positive pressure formed causes the sample solution in the sample bottle to pass through the chromatography column at the second set flow rate. The effluent is collected in the second collection bottle. S23, the Y-axis robotic arm raises the outlet of the chromatography column above the mouth of the second collection bottle.

5. The fully automated radionuclide separation solid-phase extraction method according to claim 4, characterized in that, Step S22 is followed by: After all the liquid has flowed through the chromatography column and the syringe pump has reached zero, the syringe pump switches to the air channel to draw in a third set volume of air. Then, the syringe pump is connected to the sample bottle through a multi-port solenoid valve. The syringe pump then pumps the third set volume of air into the sample bottle, emptying the sample solution in the sample bottle and the chromatography column.

6. The fully automated radionuclide separation solid-phase extraction method according to claim 1, characterized in that, Step S3 is as follows: S31. Move the tray horizontally to directly below the chromatography column, and lower the outlet of the chromatography column below the mouth of the third collection bottle. S32. Connect the syringe pump to the first reagent bottle through a multi-port solenoid valve, and the syringe pump accurately draws the required volume of the first reagent solution into the buffer tube. S33. The syringe pump is switched to the air tube channel to draw a second quantitative volume of air, which is the volume of the empty tube between the second channel of the multi-way solenoid valve and the chromatography column. S34. Connect the syringe pump to the sample bottle through a multi-port solenoid valve. Use the syringe pump to push air to deliver the first reagent solution in the buffer tube to the sample bottle. Then, use the syringe pump to push the first reagent solution through the chromatography column at a third set flow rate. The eluent is collected in the third collection bottle. S35, the Y-axis robotic arm raises the outlet of the chromatography column above the mouth of the third collection bottle.

7. The fully automated radionuclide separation solid-phase extraction method according to claim 6, characterized in that, Step S34 is followed by: After all the liquid has flowed through the chromatography column and the syringe pump has reached zero, the syringe pump switches to the air channel to draw in a third set volume of air. Then, the syringe pump is connected to the sample bottle through a multi-port solenoid valve. The syringe pump then pumps the third set volume of air into the sample bottle, emptying the sample solution in the sample bottle and the chromatography column.

8. The fully automated solid-phase extraction method for radionuclide separation according to any one of claims 1-7, characterized in that, After the effluent from each step is collected, connect the air tube and buffer tube in the three-way valve head at the front end of the syringe pump to restore the pressure in the entire system to atmospheric pressure.

9. The fully automated solid-phase extraction method for radionuclide separation according to claim 5, characterized in that, The volume range of the first set volume of air, the second set volume of air, and the third set volume of air is 5-200 mL.

10. The fully automated solid-phase extraction method for radionuclide separation according to claim 1, characterized in that, The set flow rate range for reagent solutions passing through the chromatography column is 0.5-5 mL / min; the set flow rate range for sample solutions passing through the chromatography column is 0.5-3 mL / min.

Images