Liquid sample filtering device with extremely low system operation volume, membrane concentration system and concentration method

Abstract

The invention relates to the technical field of concentration devices, in particular to a liquid sample filtering device with an extremely low system operation volume, a membrane concentration system and a concentration method. The filtering device provided by the invention can carry nanofiltration and reverse osmosis membranes with different molecular weight cutoff, and can effectively remove large and small non-target impurities, thereby achieving the purpose of selectively intercepting and concentrating target objects according to the molecular weight. Meanwhile, an ultrasonic generator is arranged in the filtering device and can be used for carrying out ultrasonic treatment on the positions of the first groove, the second groove and the filtering membrane, so that the filtering effect is effectively improved. The membrane concentration and filtration system provided by the invention adopts a circulating pre-filtration and concentration circulating mode, and the operation volume of the system can be reduced to an extremely low level of several milliliters, so that concentration of a small amount of liquid samples is realized. According to the invention, the consumption of samples required by detection can be greatly reduced, and the method is particularly suitable for concentration and detection of precious or difficult-to-obtain samples.

Description

Technical Field

[0001] The invention relates to the technical field of concentration devices, in particular to a liquid sample filtering device with extremely low system operation volume, a membrane concentration system and a concentration method. Background Art

[0002] At present, laboratories usually use extraction, evaporation, nitrogen blowing, solid phase extraction, supercritical extraction and other methods to concentrate samples in order to increase the concentration of the target analyte, but these methods all have certain defects. The extraction method often requires the introduction of organic solvents, which is not green and environmentally friendly. At the same time, the use of some toxic organic solvents will also pose a threat to the safety of experimenters; the evaporation method has high energy consumption and is prone to cause the loss of volatile target analytes; the nitrogen blowing method is not suitable for volatile substances and is time-consuming; the solid phase extraction method requires the selection of different stationary phase materials according to the properties of the target analyte, and the extraction column is generally disposable; the supercritical extraction method has high equipment costs and has certain selectivity for the target analyte.

[0003] Nanofiltration and reverse osmosis membrane technologies are green, environmentally friendly, and have low energy consumption. They have been successfully applied in the fields of seawater desalination, sewage treatment, and pure water preparation, and have mature commercial equipment. At the same time, literature shows that nanofiltration membranes and reverse osmosis membranes have good performance in intercepting various organic and inorganic substances.

[0004] However, when faced with a small amount of liquid samples in the laboratory that need to be concentrated (sample volume <50mL), the existing instrument system is too large (the system operating volume is at least several hundred mL), which makes it impossible to concentrate a small amount of liquid samples. Therefore, it is urgent to design a pretreatment device that can be used for concentrating a small amount of liquid samples, so as to innovate the pretreatment method of liquid samples and expand the application scope of green and environmentally friendly membrane technology. Summary of the invention

[0005] The purpose of the present invention is to overcome the problem that it is difficult to apply nanofiltration and reverse osmosis membrane technology to a small amount of liquid sample concentration equipment in the prior art, and to provide a liquid sample filtration device, a membrane concentration system and a concentration method with an extremely low system operating volume.

[0006] The technical solution provided by the present invention is as follows:

[0007] A liquid sample filtering device with extremely low system operation volume comprises an upper module and a lower module;

[0008] The top of the upper module is provided with a liquid inlet and a liquid return port on both sides, the bottom of the upper module is provided with a first groove, the first groove is provided with a liquid inlet hole and a liquid return hole, and the outer ring of the first groove is provided with a sealing ring;

[0009] The lower module is provided with a second groove, and a liquid outlet is provided on the side. The second groove is arranged opposite to the first groove and is sealed and connected through a sealing ring. A guide groove is provided inside the second groove. The guide groove includes a main guide groove and a plurality of sub-guide grooves arranged crosswise with the main guide groove. One end of the main guide groove extends to one side of the lower module and is connected to the liquid outlet.

[0010] An ultrasonic generator for transmitting ultrasound into the first groove or the second groove is arranged in the upper module or / and the lower module.

[0011] As an improvement, a receiving groove is provided in the second groove, and a high borax core for supporting and fixing the filter membrane is provided in the receiving groove.

[0012] As an improvement, a filter membrane is provided between the first groove and the second groove, and the outer side of the filter membrane is pressed and sealed by a sealing ring.

[0013] As an improvement, the number of the liquid inlet holes and the liquid return holes are both multiple, and they are connected to the liquid inlet and the liquid return port respectively.

[0014] As an improvement, the depth of the main flow channel is greater than the depth of the sub-flow channel, and the sub-flow channels are multiple in number and are arranged perpendicular to the main flow channel.

[0015] The present invention also discloses a liquid sample membrane concentration system with extremely low system operation volume, comprising a circulating pre-filtration component, a circulating concentration component and a sample liquid concentration tank;

[0016] The circulation pre-filtration comprises a sample bottle, a pump and a filter device connected by a conduit, wherein the pump draws sample liquid from the sample bottle and delivers it from the liquid inlet to the filter device, the filtrate filtered by the filter device is discharged from the liquid outlet and delivered to the sample liquid concentration tank, and the residual liquid filtered by the filter device is returned to the sample bottle through the liquid return port for circulation pre-filtration;

[0017] The circulation concentration component includes a second pump and a second filter device. The second pump extracts the sample liquid after pre-filtration from the sample liquid concentration tank, and then transports it from the liquid inlet to the second filter device. The waste liquid filtered by the second filter device is discharged from the liquid outlet, and the sample liquid that has not passed the filtration is transported from the liquid return port to the sample liquid concentration tank for circulation concentration.

[0018] An absorbance monitor is provided between the liquid return port of the second filtering device and the sample liquid concentration tank;

[0019] The first filter device and the second filter device both adopt the above-mentioned filter device.

[0020] As an improvement, the pump 1 and the pump 2 both use double-plunger series infusion pumps, and the catheters both use peek tubes.

[0021] As an improvement, in the circulating pre-filtration assembly, an overflow valve and a pressure sensor are provided between the liquid return port of the first filtration device and the sample bottle.

[0022] As an improvement, in the circulation concentration component, a second pressure flow valve and a second pressure sensor are further provided between the liquid return port of the second filter device and the sample liquid concentration tank.

[0023] The method for concentrating using the system of the present invention is as follows: filter membranes with different molecular weight cutoffs are arranged in the circulating pre-filtration component and the circulating concentration component;

[0024] The molecular weight cutoff of the filter membrane in the circulating pre-filtration component is greater than the target molecular weight of the sample, and can filter out impurities in the sample liquid that are larger than the sample, and only allow water, sample and impurities with molecular weights smaller than the sample to pass through; the filtrate that passes through the filter membrane is transported to the sample liquid concentration tank through the liquid outlet of the filter device 1, and the filtrate that does not pass through the filter membrane is transported to the sample bottle through the return pipe for circulating pre-filtration;

[0025] The molecular weight cutoff of the filter membrane in the circulation concentration component is smaller than the target molecular weight of the sample, and water and impurities with a molecular weight smaller than the sample can be allowed to pass through while retaining the sample and part of the water. The filtered water and small molecular weight impurities are discharged from the liquid outlet of the second filter device, and the remaining sample and part of the water are returned to the sample liquid concentration tank through the return liquid port of the second filter device for circulation concentration and purification;

[0026] During the cyclic concentration process, the filtration concentration effect is monitored in real time by an absorbance monitor and the process stops when the specified concentration is reached.

[0027] The advantages of the present invention are:

[0028] 1. The filter device of the present invention can be equipped with nanofiltration and reverse osmosis membranes with different molecular weight cutoffs, which can effectively remove larger and smaller non-target impurities, thereby achieving the purpose of selectively intercepting and concentrating the target according to molecular weight. At the same time, an ultrasonic generator is provided in the filter device to perform ultrasonic treatment on the first groove, the second groove and the filter membrane position, effectively improving the filtering effect. At the same time, the ultrasound can also produce an oscillation effect on the filter membrane during filtering, which has a cleaning effect, avoids clogging of the filter membrane, and improves the filtering efficiency.

[0029] 2. The membrane concentration system of the present invention adopts the method of cyclic prefiltration and cyclic concentration, and can operate at a relatively small sample volume. The system can handle the concentration of samples with a sample volume of less than 50 mL, and at the limit, it can handle the concentration of extremely low-level samples with a sample volume of less than 10 mL. The present invention can greatly reduce the consumption of samples required for detection, and is particularly suitable for the concentration and inspection of precious or difficult-to-obtain samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a structural diagram of a liquid sample filtering device with extremely low system operating volume in Example 1.

[0031] Figure 2 This is an exploded view of a liquid sample filtration device with extremely low system operating volume in Example 1.

[0032] Figure 3 This is a structural diagram of the bottom of the upper module in a liquid sample filtration device with extremely low system operating volume in Example 1.

[0033] Figure 4 This is a structural diagram of the lower module in a liquid sample filtration device with extremely low system operating volume in Example 1.

[0034] Figure 5 This is a structural diagram of the connection between the upper module and the lower module in a liquid sample filtration device with an extremely low system operating volume in Example 1.

[0035] Figure 6 This is a diagram of the internal structure of the lower module in a liquid sample filtration device with an extremely low system operating volume in Example 1.

[0036] Figure 7 This is a structural diagram of a liquid sample membrane concentration system with extremely low system operating volume in Example 1.

[0037] Indicated in the figure:

[0038] 1-upper module, 11-liquid inlet, 12-liquid return port, 13-first groove, 14-liquid inlet hole, 15-liquid return hole, 16-sealing ring, 2-lower module, 21-second groove, 22-liquid outlet, 23-receiving groove, 24-guide groove, 241-main guide groove, 242-sub-guide groove, 25-high borax core, 3-filter membrane, 4-ultrasonic generator, 5-circulation pre-filtration component, 51-filter device one, 52-sample bottle, 53-pump one, 54-pressure sensor, 55-overflow valve, 6-circulation concentration component, 61-filter device two, 62-pump two, 63-second pressure flow valve, 64-second pressure sensor, 7-sample liquid concentration tank, 8-absorbance monitor. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0040] Example 1

[0041] This embodiment discloses a liquid sample filtering device with extremely low system operation volume, comprising an upper module 1 and a lower module 2;

[0042] A liquid inlet 11 and a liquid return port 12 are respectively provided on both sides of the top of the upper module 1, and a first groove 13 is provided on the bottom surface of the upper module 1. A liquid inlet hole 14 and a liquid return hole 15 are provided in the first groove 13, and a sealing ring 16 is provided on the outer ring of the first groove 13. The number of liquid inlet holes 14 and liquid return holes 15 are both 4, and they are respectively connected to the liquid inlet 11 and the liquid return port 12. In practical applications, the number of liquid inlet holes 14 and liquid return holes 15 can also be changed according to needs.

[0043] The lower module 2 is provided with a second groove 21, and a liquid outlet 22 is provided on the side. The second groove 21 is arranged opposite to the first groove 13 and is sealed and connected through a sealing ring 16. The outer ring of the second groove 21 is provided with a receiving groove 23, and a high borax core 25 is provided in the receiving groove 23. A filter membrane 3 is provided between the first groove 13 and the second groove 21.

[0044] like Figure 5 As shown, the area of ​​the first groove 13 is the same as the area of ​​the second groove 21. The sealing ring 16 is arranged along the edge of the first groove 13 and the second groove 21, and is used to seal the filtration space surrounded by the first groove 13 and the second groove 21. The receiving groove 23 is arranged inside the sealing ring 16 and sinks 0.4 cm. The high borax core 25 is arranged inside the receiving groove 23, and is used to support the filter membrane 3, and the filter membrane 3 is crimped to the top of the first groove 13 for fixing. The outer edge of the high borax core 25 is tightly fitted with the inner ring of the sealing ring 16 to ensure the airtightness during filtration.

[0045] A guide groove 24 is provided inside the second groove 21, and the guide groove 24 includes a main guide groove 241 and a plurality of sub-guide grooves 242 arranged crosswise with the main guide groove 241. One end of the main guide groove 241 extends to one side of the lower module 2 and is connected to the liquid outlet 22. The depth of the main guide groove 241 is greater than the depth of the sub-guide groove 242. The number of sub-guide grooves 242 is multiple and is arranged perpendicular to the main guide groove 241. The arrangement of the sub-guide grooves 242 can effectively increase the coverage area of ​​the guide groove 24, and the filtrate passing through the filter membrane 3 can quickly pass through the sub-guide grooves 242 and merge into the main flow 241, and then be discharged through the liquid outlet 22.

[0046] The filter membrane 3 divides the area between the first groove 13 and the second groove 21 into two chambers. The filtrate passes through the filter membrane 3 and enters the second groove 21 and the guide groove 24, and then is discharged from the liquid outlet 22; the part that cannot pass through the filter membrane 3 is returned and circulated and filtered through the return liquid port 12.

[0047] An ultrasonic generator 4 is provided inside the filter device for ultrasonicating the first groove 13 or the second groove 21. The ultrasonic generator 4 adopts a small ultrasonic transducer, which can be built into the upper module 1 or the lower module 2, or can be arranged on the upper module 1 or the lower module 2 at the same time. The ultrasonic generator 4 can be connected to an external control device through a wire, and the power size is controlled by the external control module controller. Small ultrasonic transducers are prior art, and there are many specific structures, such as CN102397837A, which will not be further described here. The installed ultrasonic generator 4 can achieve real-time weakening of the concentration polarization effect to increase the filtration efficiency, and can also have a cleaning effect on the filter membrane 3, so as to achieve the purpose of cyclic processing of different samples.

[0048] The present invention also discloses a liquid sample membrane concentration system with extremely low system operation volume, comprising a circulating pre-filtering component 5, a circulating concentration component 6 and a sample liquid concentration tank 7. The circulating pre-filtering component 5 and the circulating concentration component 6 are both provided with the above-mentioned filtering device, and for the convenience of distinction, the filtering devices in the two components are named filtering device one 51 and filtering device two 61 respectively.

[0049] The circulation pre-filtration 5 comprises a sample bottle 52, a pump 53 and a filter device 51 connected by a conduit. The pump 53 extracts sample liquid from the sample bottle 52 and delivers it to the filter device 51 from the liquid inlet 11. The filtrate filtered by the filter device 51 is discharged from the liquid outlet 22 and delivered to the sample liquid concentration tank 7. The residual liquid filtered by the filter device 51 is returned to the sample bottle 52 through the liquid return port 12 for circulation pre-filtration. An overflow valve 55 and a pressure sensor 54 are provided between the liquid return port 22 of the filter device 51 and the sample bottle 52.

[0050] The circulation concentration component 6 includes a pump 2 62 and a filter 2 61. The pump 2 62 extracts the sample liquid after pre-filtration from the sample liquid concentration tank 7, and then transports it to the filter 2 61 from the liquid inlet 11. The waste liquid filtered by the filter 2 61 is discharged from the liquid outlet 22, and the sample liquid that has not passed through is transported from the liquid return port 12 to the sample liquid concentration tank 7 for circulation concentration; an absorbance monitor 8 is provided between the liquid return port 12 of the filter 2 61 and the sample liquid concentration tank 7. The absorbance monitor 8 can monitor the concentration effect of the target object with light absorption effect in real time. A second overflow valve 63 and a second pressure sensor 64 are also provided between the liquid return port 22 of the filter 2 61 and the sample liquid concentration tank 7.

[0051] In this embodiment, both pump 1 53 and pump 2 62 use double plunger series infusion pumps, such as the DP series double plunger high pressure constant flow infusion pump produced by Oushisheng, which can provide a stable liquid flow rate and adjust the filtrate flow rate and pressure according to the feedback of the pressure sensor 54 or the second pressure sensor 64. The catheters are all peek tubes, which have the advantages of high strength and high pressure resistance.

[0052] The method for concentrating using the system of the present invention is as follows: filter membranes with different molecular weight cutoffs are arranged in the circulating pre-filtration component and the circulating concentration component;

[0053] The molecular weight cutoff of the filter membrane in the circulating pre-filtration component is greater than the target molecular weight of the sample, and can filter out impurities in the sample liquid that are larger than the sample, and only allow water, sample and impurities with molecular weights smaller than the sample to pass through; the filtrate that passes through the filter membrane is transported to the sample liquid concentration tank through the liquid outlet of the filter device 1, and the filtrate that does not pass through the filter membrane is transported to the sample bottle through the return pipe for circulating pre-filtration;

[0054] The molecular weight cutoff of the filter membrane in the circulation concentration component is smaller than the target molecular weight of the sample, and water and impurities with a molecular weight smaller than the sample can be allowed to pass through while retaining the sample and part of the water. The filtered water and small molecular weight impurities are discharged from the liquid outlet of the second filter device, and the remaining sample and part of the water are returned to the sample liquid concentration tank through the return liquid port of the second filter device for circulation concentration and purification;

[0055] During the cyclic concentration process, the filtration concentration effect is monitored in real time by an absorbance monitor and the process stops when the specified concentration is reached.

[0056] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A liquid sample filtering device with extremely low system operating volume, characterized in that: It includes an upper module and a lower module; The top of the upper module is provided with a liquid inlet and a liquid return port on both sides, the bottom of the upper module is provided with a first groove, the first groove is provided with a liquid inlet hole and a liquid return hole, and the outer ring of the first groove is provided with a sealing ring; The lower module is provided with a second groove, and a liquid outlet is provided on the side. The second groove is arranged opposite to the first groove and is sealed and connected through a sealing ring. A guide groove is provided inside the second groove. The guide groove includes a main guide groove and a plurality of sub-guide grooves arranged crosswise with the main guide groove. One end of the main guide groove extends to one side of the lower module and is connected to the liquid outlet. An ultrasonic generator for transmitting ultrasound into the first groove or the second groove is arranged in the upper module or / and the lower module.

2. The liquid sample filtering device with extremely low system operating volume according to claim 1, characterized in that: A receiving groove is arranged in the second groove, and a high borax core for supporting and fixing the filter membrane is arranged in the receiving groove.

3. The liquid sample filtering device with extremely low system operating volume according to claim 2, characterized in that: A filter membrane is arranged between the first groove and the second groove, and the outer side of the filter membrane is pressed and sealed by a sealing ring.

4. The liquid sample filtering device with extremely low system operating volume according to claim 1, characterized in that: The number of the liquid inlet holes and the liquid return holes are both multiple, and are respectively connected with the liquid inlet and the liquid return port.

5. The liquid sample filtering device with extremely low system operating volume according to claim 1, characterized in that: The depth of the main flow channel is greater than the depth of the sub-flow channel, and the sub-flow channels are multiple in number and are arranged perpendicular to the main flow channel.

6. A liquid sample membrane concentration system with extremely low system operating volume, characterized in that: It includes a circulating pre-filtration component, a circulating concentration component and a sample liquid concentration tank; The circulation pre-filtration comprises a sample bottle, a pump and a filter device connected by a conduit, wherein the pump draws sample liquid from the sample bottle and delivers it from the liquid inlet to the filter device, the filtrate filtered by the filter device is discharged from the liquid outlet and delivered to the sample liquid concentration tank, and the residual liquid filtered by the filter device is returned to the sample bottle through the liquid return port for circulation pre-filtration; The circulation concentration component includes a second pump and a second filter device. The second pump extracts the sample liquid after pre-filtration from the sample liquid concentration tank, and then transports it from the liquid inlet to the second filter device. The waste liquid filtered by the second filter device is discharged from the liquid outlet, and the sample liquid that has not passed the filtration is transported from the liquid return port to the sample liquid concentration tank for circulation concentration. An absorbance monitor is provided between the liquid return port of the second filtering device and the sample liquid concentration tank; The first filter device and the second filter device both adopt the filter device as described in any one of claims 1 to 5.

7. A liquid sample membrane concentration system with extremely low system operating volume according to claim 6, characterized in that: The first pump and the second pump both adopt double plunger series infusion pumps, and the catheters both adopt peek tubes.

8. The liquid sample membrane concentration system with extremely low system operation volume according to claim 6, characterized in that: An overflow valve and a pressure sensor are arranged between the liquid return port of the first filtering device and the sample bottle.

9. The liquid sample membrane concentration system with extremely low system operation volume according to claim 6, characterized in that: A second pressure flow valve and a second pressure sensor are also provided between the liquid return port of the second filtering device and the sample liquid concentration tank.

10. A method for concentrating a liquid sample based on the extremely low system operating volume membrane concentration system of claim 6, characterized in that: Filter membranes with different molecular weight cutoffs are arranged in the circulation pre-filtration component and the circulation concentration component; The molecular weight cutoff of the filter membrane in the circulating pre-filtration component is greater than the target molecular weight of the sample, and can filter out impurities in the sample liquid that are larger than the sample, and only allow water, sample and impurities with molecular weights smaller than the sample to pass through; the filtrate that passes through the filter membrane is transported to the sample liquid concentration tank through the liquid outlet of the filter device 1, and the filtrate that does not pass through the filter membrane is transported to the sample bottle through the return pipe for circulating pre-filtration; The molecular weight cutoff of the filter membrane in the circulation concentration component is smaller than the target molecular weight of the sample, and water and impurities with a molecular weight smaller than the sample can be allowed to pass through while retaining the sample and part of the water. The filtered water and small molecular weight impurities are discharged from the liquid outlet of the second filter device, and the remaining sample and part of the water are returned to the sample liquid concentration tank through the return liquid port of the second filter device for circulation concentration and purification; During the cyclic concentration process, the filtration concentration effect is monitored in real time by an absorbance monitor, and the process stops when the specified concentration is reached.

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