Microchip electrophoresis non-contact conductivity detection system with adjustable detection distance
By employing an adjustable detection cell structure and external electrode combination in the microfluidic chip electrophoresis detection system, the problem of non-adjustable detection distance is solved, enabling flexible optimization of electrophoresis conditions and high integration, thereby reducing the difficulty and cost of chip fabrication.
Patent Information
- Application Number
- CN202422868130.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-25
- Publication Date
- 2025-10-24
- Estimated Expiration
- 2034-11-25
AI Technical Summary
In existing microfluidic chip electrophoresis detection systems, the fixed external electrodes result in an unadjustable detection distance, which increases the difficulty and cost of chip fabrication and is not conducive to optimizing electrophoretic separation conditions.
The detection system consists of a detection pool base and an outer cover. Combined with horizontal and vertical partitions, it features an adjustable chip fixing fixture, enabling flexible combination of microfluidic chips and non-contact conductivity detection electrode sheets. The detection distance can be adjusted by adjusting the screw holes and fixtures. It integrates excitation and pickup electrodes, and the external electrodes can be replaced to adapt to different parameters.
It enables flexible adjustment of detection distance, optimizes electrophoretic separation conditions, improves the flexibility and integration of use, and reduces the complexity and cost of chip manufacturing.
Smart Images
Figure CN223470995U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to micro -fluidic chip electrophoresis detection equipment technical field relates to a kind of for the detection distance adjustable non-contact conductivity detection system of micro -fluidic chip electrophoresis. BACKGROUND
[0002] Microchip capillary electrophoresis (MCE) is a technology that performs electrophoretic separation in a micron-scale channel. It is derived from capillary electrophoresis, and integrates the electrophoretic analysis process originally performed in a capillary onto a microchip with a size of only a few square centimeters, realizing sample injection, separation, detection, etc. MCE technology is highly compatible with the development direction of modern analysis instrument integration and miniaturization, has been combined with various detection systems such as optical detectors, mass spectrometry detectors, and electrochemical detectors, and has been widely applied in food safety, environmental monitoring, and biomedical fields.
[0003] Among them, the non-contact conductivity detector has the advantages of simple structure, small size and low cost, and has good internal compatibility with miniaturization technology, and stands out among various detectors for chip electrophoresis. The principle of non-contact conductivity detection is that the excitation electrode couples the radio frequency signal into the microchannel, and after interaction with the ions, the output signal is collected by the pickup electrode. Usually, the excitation electrode and the pickup electrode for microfluidic chip electrophoresis are integrated with the microchannel on the microfluidic chip, which requires a relatively complex chip manufacturing method, increasing the difficulty and cost of chip manufacturing. Placing the electrode outside the chip is a good alternative. However, in current research, the external electrode is usually integrated on the conductivity cell, and the electrode parameters cannot be changed as needed. Moreover, since the electrode is fixed, the microfluidic chip electrophoresis detection distance is also fixed, which is not conducive to optimizing the electrophoretic separation conditions. SUMMARY
[0004] The utility model aims at providing a kind of microchip electrophoresis non-contact conductivity detection system with adjustable detection distance, which avoids direct machining of electrodes on the chip on one hand, and on the other hand, has adjustable electrophoretic detection distance to facilitate optimization of electrophoretic separation conditions, and the electrode can be replaced according to different electrode parameters, increasing the flexibility of use.
[0005] To achieve the above-mentioned purpose, the utility model adopts the following technical solutions:
[0006] The application discloses a kind of detection distance adjustable microchip electrophoresis non-contact conductivity detection system, including mutually coordinated detection cell base and detection cell shell cover, detection cell base inside is provided with transverse partition and longitudinal partition, and transverse partition and longitudinal partition are connected in T shape;The top of transverse partition is staggered with chip placement slot and non-contact conductivity detection electrode slot, and chip placement slot and non-contact conductivity detection electrode slot are perpendicular to each other, and the depth of non-contact conductivity detection electrode slot is deeper than the depth of chip placement slot;Microfluidic chip and non-contact conductivity detection electrode piece are placed in chip placement slot and non-contact conductivity detection electrode slot respectively, and microfluidic chip is closely attached to non-contact conductivity detection electrode piece, and two electrodes are arranged in parallel on non-contact conductivity detection electrode piece close to microchannel of microfluidic chip, and the two electrodes are respectively excitation electrode and pickup electrode, excitation electrode is connected with signal input BNC connector arranged on the side wall of one side cavity below transverse partition by wire, pickup electrode is connected with circuit board arranged in the other side cavity below transverse partition by wire, and signal output BNC connector is arranged opposite to signal input BNC connector on circuit board;Detection cell shell cover is also provided with detection hole corresponding to liquid pool on microfluidic chip.
[0007] To realize that microfluidic chip electrophoresis detection distance is adjustable, the left and right sides of the chip placement slot are provided with a plurality of adjusting screw holes, at least one set of chip fixing clamps is installed on the adjusting screw holes, each set of chip fixing clamps comprises a clamping piece and adjusting screw rods arranged on the two sides of the clamping piece, and the adjusting screw rods are threadedly connected with the adjusting screw holes.
[0008] Compared with the prior art, the microchip electrophoresis non-contact conductivity detection system has the following beneficial effects:
[0009] 1) The chip electrophoresis detection distance can be flexibly adjusted, so that the electrophoresis conditions can be optimized to obtain the best separation effect.
[0010] 2) The electrode can be flexibly replaced, so that the electrode parameters can be adjusted to adapt to different microfluidic chips.
[0011] 3) The microfluidic chip and its fixing clamp, input and detection circuit parts are integrated in the detection cell, and the integration degree is high. BRIEF DESCRIPTION OF DRAWINGS
[0012] Figure 1 It is the disassembly schematic view of the microchip electrophoresis non-contact conductivity detection system of the application.
[0013] Figure 2 It is the assembly schematic view of the microchip electrophoresis non-contact conductivity detection system of the application.
[0014] Figure 3 It is the circuit diagram of the circuit board of the microchip electrophoresis non-contact conductivity detection system of the application.
[0015] Figure 4 is the chip electrophoresis spectrum of the microchip electrophoresis non-contact conductivity detection system.
[0016] In the figure: 1. detection pool shell cover, 2. detection hole, 3. detection pool base, 4. adjusting screw hole, 5. chip placing groove, 6. transverse partition, 7. longitudinal partition, 8. non-contact conductivity detection electrode groove, 9. clamping piece, 10. adjusting screw, 11. microfluidic chip, 12. signal input BNC connector, 13. signal output BNC connector, 14. non-contact conductivity detection electrode sheet, 15. circuit board. DETAILED DESCRIPTION
[0017] The utility model makes further explanation and description in combination with the drawings and specific implementation.
[0018] As Figures 1-2 shown, the utility model microchip electrophoresis non-contact conductivity detection system, including mutually coordinated detection pool base 3 and detection pool shell cover 1, detection pool base 3 inside is provided with transverse partition 6 and longitudinal partition 7, and transverse partition 6 and longitudinal partition 7 are connected in T shape;Detection pool base 3 is divided into upper and lower spaces by transverse partition 6, and the lower space is divided into two cavities by longitudinal partition 7.
[0019] Transverse partition 6 top is provided with chip placing groove 5 and non-contact conductivity detection electrode groove 8, and chip placing groove 5 and non-contact conductivity detection electrode groove 8 are perpendicular to each other, and chip placing groove 5 is located above non-contact conductivity detection electrode groove 8, and the depth of non-contact conductivity detection electrode groove 8 is deeper than the depth of chip placing groove 5;Microfluidic chip 11 is placed in chip placing groove 5, and non-contact conductivity detection electrode sheet 14 is tightly arranged below microfluidic chip 11, and non-contact conductivity detection electrode sheet 14 is located in non-contact conductivity detection electrode groove 8, and two electrodes are arranged in parallel on non-contact conductivity detection electrode sheet 14 close to the microchannel of microfluidic chip 11, and the two electrodes are excitation electrode and pickup electrode respectively, excitation electrode is connected with signal input BNC connector 12 arranged on the side wall of one side cavity below transverse partition 6 through wire, and pickup electrode is connected with circuit board 15 arranged in the other side cavity below transverse partition 6 through wire, and signal output BNC connector 13 opposite to signal input BNC connector 12 is connected on circuit board 15.
[0020] Detection pool shell cover 1 is also provided with detection hole 2 corresponding to liquid pool on microfluidic chip 11.
[0021] Chip placing groove 5 left and right sides are provided with a plurality of adjusting screw holes 4, and at least one set of chip fixing clamps is installed on adjusting screw hole 4, each chip fixing clamp includes a clamping piece 9 and an adjusting screw 10 threaded through the two sides of the clamping piece 9, and the adjusting screw 10 is screwed with the adjusting screw hole 4.
[0022] In use, first, the microfluidic chip 11 and the non-contact conductivity detection electrode sheet 14 are respectively placed in the chip placement groove 5 and the non-contact conductivity detection electrode groove 8, then the fixing clamp is installed on the adjusting screw hole 4, the microfluidic chip 11 and the non-contact conductivity detection electrode sheet 14 are clamped and fixed by the fixing clamp, and the position of the microfluidic chip 11 can be adjusted according to the position of the adjusting screw hole 4, by adjusting the fixed position of the microfluidic chip 11, the relative position of the microchannel and the conductivity detection electrode sheet 14 can be changed, and then the detection distance (the detection distance is from the cross center of the chip microchannel to the contact position of the channel and the non-contact conductivity detection electrode sheet 14) can be flexibly adjusted, then the detection pool shell cover 1 is covered, and the detection pool shell cover 1 and the detection pool base 3 form a conductivity detection pool, the inside of the conductivity detection pool is coated with conductive copper paint, and a ground wire is connected, so as to shield external electromagnetic interference.
[0023] In detection, a voltage is applied to each liquid pool on the microfluidic chip 11 by using a platinum electrode, under the action of the voltage in the liquid pool, the solution in the microchannel migrates, when the solution moves to the detection electrode position at the end of the channel (that is, the non-contact conductivity detection electrode sheet 14), a high-frequency alternating current signal generated by an external signal generator is input to the excitation electrode on the non-contact conductivity detection electrode sheet 14 through the signal input BNC joint 12, the excitation signal is coupled with the solution in the microchannel of the microfluidic chip 11, after interaction with ions, the output signal is collected by the pickup electrode on the non-contact conductivity detection electrode sheet 14 and then input to the circuit board 15 for signal amplification and conversion, and then output to an external signal acquisition device (computer) through the signal output BNC joint 13, and finally the non-contact conductivity signal of the sample is obtained.
[0024] In the above detection process, because the pickup electrode is very close to the circuit board, external electromagnetic interference on the output signal in the transmission process is effectively avoided, which is the advantage of high integration of the conductivity detection pool. The microchip used in the microfluidic chip 11 is disclosed in the prior art, and details are shown in [Wang Mengyou. PDMS / PDMS Film Microchip Electrophoresis-Non-contact Conductivity Detection Method Research and Application [D]. Central South University, 2022. DOI: 10.27661 / d.cnki.gzhnu.2022.004785.]; the circuit diagram of the circuit board 15 is shown in Figure 3 , the current-voltage conversion is performed by OPA140, the signal amplification is performed by AD637, and the signal is further processed and output by INA128, subsequent data analysis and processing are the prior art, and do not involve the innovative points of the utility model, which will not be described here.
[0025] Finally, the model sample is detected by using the microchip electrophoresis non-contact conductivity detection system of the utility model, and the detection sample is 250 nM of potassium ion (K + ), sodium ion (Na +) and lithium ion (Li + ). The sample was separated by microfluidic chip electrophoresis, and the background buffer solution was 10 mM acetic acid. The microfluidic chip channel was modified by polyacrylic acid, and the chip channel diameter was 75 μm. Adjusting the detection distance can change the separation degree of the sample. After optimization, the three ions cannot be completely separated when the detection distance is less than 2.5 cm, and the three ions can be completely separated when the detection distance is 2.5 cm, among which Na + and Li + The separation degree is greater than 2. The separation field strength is 350 V / cm, the distance between the chip channel and the electrode is 400 μm, and the excitation signal frequency is 204 kHz. Figure 4 It is the electropherogram of the non-contact conductivity signal of the sample detected in this embodiment. The spectrum shows that the three ions have good separation degree after the detection distance is optimized, which proves that the utility model can realize the detection of different ions.
Claims
1. A distance-adjustable microchip electrophoresis noncontact conductivity detection system, characterized in that: The application relates to a detection cell shell cover (1) and a detection cell base (3) which are matched with each other, the inside of the detection cell base (3) is provided with a transverse partition plate (6) and a longitudinal partition plate (7), the transverse partition plate (6) and the longitudinal partition plate (7) are connected in a T shape; the top of the transverse partition plate (6) is staggeredly provided with a chip placing groove (5) and a non-contact electric conductance detection electrode groove (8), and the chip placing groove (5) and the non-contact electric conductance detection electrode groove (8) are perpendicular to each other; a micro-fluidic chip (11) and a non-contact electric conductance detection electrode sheet (14) are respectively placed in the chip placing groove (5) and the non-contact electric conductance detection electrode groove (8), the micro-fluidic chip (11) is tightly attached to the non-contact electric conductance detection electrode sheet (14), two electrodes are parallelly arranged on the non-contact electric conductance detection electrode sheet (14) close to a micro-channel of the micro-fluidic chip (11), the two electrodes are respectively an excitation electrode and a pickup electrode, the excitation electrode is connected with a signal input BNC connector (12) arranged on the side wall of a cavity below the transverse partition plate (6) through a wire, the pickup electrode is connected with a circuit board (15) arranged in another cavity below the transverse partition plate (6) through a wire, and the circuit board (15) is connected with a signal output BNC connector (13) arranged opposite to the signal input BNC connector (12).
2. The distance-adjustable microchip electrophoresis noncontact conductivity detection system of claim 1, wherein: A plurality of adjusting screw holes (4) are arranged on the left and right sides of the chip placing groove (5), at least one set of chip fixing clamps is installed on the adjusting screw holes (4), each set of chip fixing clamps comprises a clamping piece (9) and adjusting screw rods (10) arranged on the two sides of the clamping piece (9), and the adjusting screw rods (10) are threadedly connected with the adjusting screw holes (4).
3. The distance-adjustable microchip electrophoresis noncontact conductivity detection system of claim 1, wherein: The depth of the non-contact electric conductance detection electrode groove (8) is deeper than the depth of the chip placing groove (5).
4. The distance-adjustable microchip electrophoresis noncontact conductivity detection system of claim 1, wherein: A detection hole (2) corresponding to a liquid pool on the micro-fluidic chip (11) is further arranged on the detection cell shell cover (1).