CN110793956B - Micro-fluidic device integrating functions of trace gas enrichment and detection and preparation and detection methods thereof - Google Patents
Micro-fluidic device integrating functions of trace gas enrichment and detection and preparation and detection methods thereof Download PDFInfo
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Abstract
The invention provides a micro-fluidic device integrating functions of trace gas enrichment and detection, which comprises: the upper-layer matrix and the lower-layer substrate are bonded with each other; the upper substrate comprises a micro-channel network; the micro-channel network comprises an enrichment channel, a detection channel and an outlet channel; one end of the enrichment flow channel is connected with the fluid inlet, the other end of the enrichment flow channel is connected with the detection flow channel, and the detection flow channel is connected with the fluid outlet through the outlet flow channel; the fluid inlet and the fluid outlet are communicated with the outside; and polyfunctional group linked molecules for capturing trace gas molecules are attached to the inner wall of the enrichment flow channel through electrostatic adsorption. The invention has the characteristics of simple structure, simple and convenient operation, repeated use, high measurement precision and the like.
Description
Technical Field
The invention belongs to the technical field of gas analysis, particularly relates to a micro-fluidic device integrating gas enrichment and detection functions, and particularly relates to a micro-fluidic device for realizing trace gas molecule enrichment and detection based on surface chemical modification.
Background
The detection of trace gas molecules is of great significance. With the rapid development of economy, air pollution becomes more and more serious, and the air pollution is just a serious social problem. Air pollution can be broadly divided into urban air pollution and indoor air pollution, and is exemplified by carbonyl compounds, a major pollutant, which is mainly caused by incomplete combustion of hydrocarbon substances. In urban atmospheric pollution, automobile exhaust and industrial emission, as well as hydrocarbon photodegradation, generate a large amount of carbonyl compounds; in indoor air pollution, carbonyl compounds mainly come from chemical materials, furniture and ornaments. On the one hand, carbonyl compounds represented by aldehydes are a major harmful gas in air pollution, and among them, formaldehyde and acrolein are considered as carcinogenic substances, so that it is important to detect their contents and concentration distribution in the atmosphere. On the other hand, trace gas detection has a very important application in respiratory gas diagnostics. Respiratory gas diagnosis utilizes the existence of some specific gases related to human diseases in respiratory gas, and reflects the corresponding tissue cell metabolism change by detecting the change of human respiratory gas, which has become a novel medical diagnosis means in recent years. Studies have now demonstrated that various voc (volatile organic compounds) components of respiratory gases can be candidate markers for cancer diagnosis.
However, a pre-treatment process involving gas enrichment is important because of the low levels of certain gases in outdoor air and respiratory gases, typically at ppb (μ g/L) levels. Through gas enrichment, a large amount of low-concentration gas samples to be detected are enriched into a smaller volume, so that the concentration of the gas samples is increased, and the subsequent detection is facilitated. Common sample pretreatment methods include physical adsorption and thermal desorption. Although the efficiency of enrichment of low concentration samples after gasification can be improved, the process is time consuming, accounting for over 60% of the time required for the entire analysis process. Therefore, the method has the defects of low efficiency and long processing time, is easy to introduce analysis errors, and cannot realize real-time detection of the sample quickly and conveniently. Current conventional detection methods include post-processing analysis procedures in addition to the aforementioned pre-processing. The post-treatment analysis mainly utilizes the physical and chemical characteristics of gas molecules to realize qualitative detection. The commonly used post-processing analysis methods mainly comprise mass spectrometry, Raman spectroscopy detection, resistance detection and the like. For the detection of trace gas samples, a commonly used qualitative analysis technique is the use of a gas chromatograph and mass spectrometer (GC-MS) spectrometer. Current detection systems are expensive, large instruments and expensive to analyze. The portable Raman spectrometer can meet the requirement of quick detection of molecules. On the other hand, the micro-fluidic detection chip has the advantages of less sample consumption, high detection speed, simple and convenient operation, multifunctional integration, small volume, portability and the like, and the micro-fluidic chip is utilized to realize a high-performance and miniaturized sample pretreatment structure and a novel detection method based on Raman spectroscopy, so that the cost and time for detecting trace gas molecules can be reduced.
Some of the terms to which the invention relates:
PDMS: polydimethylsiloxane.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, provides the micro-fluidic device integrating the functions of trace gas enrichment and detection, and solves the problems of complexity, large sample consumption, time consumption and high cost of the conventional trace gas sample detection equipment; the device has the characteristics of simple structure, simple and convenient operation, repeated use, high measurement precision and the like. The technical scheme adopted by the invention is as follows:
in a first aspect of the present invention, a microfluidic device integrating functions of trace gas enrichment and detection is provided, including:
the upper-layer matrix and the lower-layer substrate are bonded with each other;
the upper substrate comprises a micro-channel network; the micro-channel network comprises an enrichment channel, a detection channel and an outlet channel;
one end of the enrichment flow channel is connected with the fluid inlet, the other end of the enrichment flow channel is connected with the detection flow channel, and the detection flow channel is connected with the fluid outlet through the outlet flow channel;
the fluid inlet and the fluid outlet are communicated with the outside;
and polyfunctional group linked molecules for capturing trace gas molecules are attached to the inner wall of the enrichment flow channel through electrostatic adsorption.
Further, the multifunctional linker molecule comprises an electropositive group, an aminooxy group and a thiol group.
Furthermore, the enrichment flow channel adopts a reciprocating bending or convolution configuration to form an enrichment area.
Further, the width of the detection flow channel is larger than that of the enrichment flow channel, so as to form a detection area.
Further, the width of the flow channel in the micro flow channel network is 5-500 μm, and the height is 5-500 μm.
Furthermore, an elastic cavity is arranged above the outlet flow channel and is connected with the pressure interface; the material between the outlet flow passage and the elastic cavity has elasticity.
Further, magnetic beads are arranged in the detection area, the surfaces of the magnetic beads are coated with gold, the surfaces of the magnetic beads coated with gold are modified by thiol molecules, and the surfaces of the magnetic beads are provided with sulfydryl; the size of the magnetic beads is larger than the width of the outlet flow channel.
Further, the material of the upper layer matrix is PDMS.
The second aspect of the present invention provides a trace gas enrichment and detection method, which may include any one of the following three methods:
a trace gas enrichment and detection method comprises the following steps:
introducing gas to be detected from a fluid inlet; polyfunctional group linked molecules for capturing trace gas molecules are attached to the inner wall of the enrichment flow channel through electrostatic adsorption; the capture and enrichment of trace gas molecules are realized on the inner wall of the enrichment flow channel;
introducing eluent from a fluid inlet into an enrichment flow channel and then into a detection flow channel; the eluent is liquid, contains nano gold particles or nano silver particles with surfaces modified by mercaptan molecules, and is used for fixing the eluted trace gas molecules;
liquid pressure between the fluid inlet and the fluid outlet is balanced through the fluid control system, and the eluent carries trace gas molecules to stay in the detection flow channel;
then carrying out Raman spectrum analysis on the detection flow channel;
a trace gas enrichment and detection method comprises the following steps:
introducing gas to be detected from a fluid inlet; polyfunctional group linked molecules for capturing trace gas molecules are attached to the inner wall of the enrichment flow channel through electrostatic adsorption; the capture and enrichment of trace gas molecules are realized on the inner wall of the enrichment flow channel;
introducing eluent from a fluid inlet into an enrichment flow channel and then into a detection flow channel; the eluent is liquid, contains nano gold particles or nano silver particles with surfaces modified by mercaptan molecules, and is used for fixing the eluted trace gas molecules;
pressure gas is accessed through the pressure interface, the material between the elastic cavity and the outlet flow channel generates elastic deformation, the outlet flow channel is closed, and the eluent carries trace gas molecules to stay in the detection flow channel;
and then performing Raman spectrum analysis on the detection flow channel.
A trace gas enrichment and detection method comprises the following steps:
introducing gas to be detected from a fluid inlet; polyfunctional group linked molecules for capturing trace gas molecules are attached to the inner wall of the enrichment flow channel through electrostatic adsorption; the capture and enrichment of trace gas molecules are realized on the inner wall of the enrichment flow channel;
introducing eluent from a fluid inlet into an enrichment flow channel and then into a detection flow channel; the eluent is liquid, so that the trapped trace gas molecules are flushed into the eluent; magnetic beads are arranged in the detection flow channel, the surfaces of the magnetic beads are coated with gold, the surfaces of the magnetic beads coated with gold are modified by thiol molecules, and the surfaces of the magnetic beads are provided with sulfydryl; carrying out double fixation on the eluted trace gas molecules by the gold and the sulfydryl on the surface of the magnetic beads;
balancing the liquid pressure between the fluid inlet and the fluid outlet through the fluid control system, and allowing the trace gas molecules to stay in the detection flow channel;
and then performing Raman spectrum analysis on the detection flow channel.
The third aspect of the invention provides a method for preparing a microfluidic device with integrated functions of trace gas enrichment and detection, which comprises the following steps:
spin-coating a layer of negative photoresist on a silicon wafer, and forming a die with a micro-channel network on the silicon wafer through a photoetching process; the thickness of the negative photoresist is larger than that of the upper substrate to be manufactured;
preparing a PDMS material and a curing agent, pouring the PDMS material on a mould, and stripping PDMS from a silicon wafer after curing to obtain an upper-layer matrix with a micro-channel network;
punching holes on the upper-layer matrix to realize the communication between the fluid inlet and the fluid outlet with the outside;
carrying out oxygen plasma treatment on the runner surface of the upper-layer matrix and the lower-layer substrate to realize negative charge on the runner surface; then bonding the upper substrate flow channel surface with the lower substrate;
introducing a polyfunctional group linked molecular solution with electropositive groups, aminoxy groups and mercapto groups into the flow channel, drying, and performing electrostatic adsorption to realize the modification of the inner surface of the flow channel; the polyfunctional group-linked molecules are adsorbed and attached to the inner surface of the flow channel by electrostatic action.
The invention has the advantages that:
1) the microfluidic device provided by the invention can be manufactured into a microfluidic chip, and gas enrichment and detection on the same chip can be realized; the structure has the characteristics of miniaturization and integration, the volume of the chip is further reduced, and the integration level of the micro-fluidic chip is greatly improved.
2) Before detection, the enrichment of trace gas is realized, and the detection time is short.
3) The trace gas can be eluted after being captured and enriched in the flow channel, and the eluent can not be adhered or combined on the inner wall of the flow channel through a chemical reaction, so that the microfluidic device can be repeatedly used, and the detection cost is greatly reduced.
4) The method is suitable for a Raman spectrum analysis detection method, and the Raman spectrum analysis has the advantages of rapidness, high information content and convenience in operation, so that more abundant information is provided in the same time compared with detection methods such as fluorescence labeling and chemical sensors, and the method has the potential of online detection compared with large-scale chemical instrument analysis methods such as mass spectrum chromatography.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of the present invention.
Fig. 2 is a schematic structural diagram of a second embodiment of the present invention.
FIG. 3 is a schematic diagram of a third structure according to an embodiment of the present invention.
Fig. 4 is a schematic diagram of an elastic cavity and a pressure interface according to a second embodiment of the present invention.
Fig. 5 is a schematic view illustrating elastic deformation of the PDMS material between the elastic cavity and the outlet channel in the second embodiment of the present invention.
Detailed Description
The invention is further illustrated by the following specific figures and examples.
Embodiment one, as shown in fig. 1;
this embodiment proposes a micro-fluidic device that trace gas enrichment and detection function are integrated, includes: an upper substrate 1 and a lower substrate 2 bonded to each other;
wherein the upper layer matrix 1 is made of PDMS material and can transmit light; the material of the lower substrate 2 can be a hard material such as glass and organic glass, and can also be a flexible material such as PDMS; the upper layer substrate 1 and the lower layer substrate 2 are bonded, so that a closed fluid channel can be formed;
the upper substrate 1 comprises a micro-channel network; the micro-channel network comprises an enrichment channel 4, a detection channel 5 and an outlet channel 7; the upper-layer matrix 1 is also provided with a fluid inlet 3 and a fluid outlet 6;
one end of the enrichment flow channel 4 is connected with the fluid inlet 3, the other end of the enrichment flow channel is connected with the detection flow channel 5, and the detection flow channel 5 is connected with the fluid outlet 6 through the outlet flow channel 7; the fluid inlet 3 and the fluid outlet 6 are both communicated with the outside; the fluid inlet 3 and the fluid outlet 6 can be communicated with the outside by perforating the upper-layer matrix 1 or the lower-layer substrate 2;
the fluid inlet 3 and fluid outlet 6 may be connected to a fluid control system by capillary tubing; the fluid control system comprises a syringe pump and a pressure pump, wherein a fluid inlet 3 is connected with the syringe pump, and a fluid outlet 6 is connected with the pressure pump;
polyfunctional group linked molecules for capturing trace gas molecules are attached to the inner wall of the enrichment flow channel 4 through electrostatic adsorption; the multifunctional linker molecule comprises an electropositive group (such as a nitrogen-containing group), an aminoxy group and a thiol group;
the width of the flow channel in the micro-flow channel network is 5-500 μm, and the height is 5-500 μm;
preferably, the enrichment flow channel 4 can adopt a reciprocating bending or convolution configuration to form an enrichment area; the length of the flow channel can be increased within a certain small range, and the contact area between the flow channel and the gas during enrichment is increased, so that the detection sensitivity is improved, and the detection limit is reduced;
more preferably, the width of the detection flow channel 5 is larger than that of the enrichment flow channel 4, so as to form a detection area.
The detection process of the trace gas is as follows:
a Raman spectrum analysis detection device is arranged above the detection flow channel 5;
gas to be detected is introduced from the fluid inlet 3; the capture and enrichment of trace gas molecules are realized on the inner wall of the enrichment flow channel 4; the carbonyl compound in the trace gas and the aminoxy group in the polyfunctional group linked molecule can generate oximation reaction, so that the trace gas molecule can be captured;
introducing eluent from a fluid inlet 3 into an enrichment flow channel 4 and then into a detection flow channel 5; the eluent is liquid (such as deionized water or some organic solvent), has almost no SERS activity, and contains gold nanoparticles or silver nanoparticles with surfaces modified by thiol molecules, and is used for fixing the eluted trace gas molecules; for example, the surface of the gold nanoparticle modified by thiol molecules has thiol groups, and the thiol groups on the surface of the gold nanoparticle can further react with the oximation reaction product to fix the eluted gas molecules; part of the surface (without sulfydryl) of the gold nanoparticles can also form covalent chemical bonds with sulfydryl in the polyfunctional group linking molecule to realize fixation; double fixation is realized; the injection flow rate of the eluent is 0.01-0.5 mL/min;
the liquid pressure between the fluid inlet 3 and the fluid outlet 6 is balanced through the fluid control system, and the eluent carries trace gas molecules to stay in the detection flow channel 5;
then, performing Raman spectrum analysis on the detection flow channel 5; gas molecules in the detection flow channel generate surface enhanced Raman scattering signals under the excitation of Raman laser, and molecular information of a gas sample to be detected can be obtained through analysis and processing of the signals; after detection, the liquid flows out from the fluid outlet 6;
on one hand, the nano gold particles or nano silver particles modified by mercaptan molecules can fix eluted gas molecules; on the other hand, the electric field at the nano metal particles is greatly enhanced, and the obvious Raman signal enhancement can be generated;
the micro-fluidic device can be repeatedly used, and before each use, polyfunctional group linked molecules for capturing trace gas molecules can be attached to the inner wall of the enrichment flow channel 4 through electrostatic adsorption.
Example two, as shown in fig. 2;
this embodiment proposes a micro-fluidic device that trace gas enrichment and detection function are integrated, includes: an upper substrate 1 and a lower substrate 2 bonded to each other;
wherein the upper layer matrix 1 is made of PDMS flexible material and can transmit light; the material of the lower substrate 2 can be a hard material such as glass and organic glass, and can also be a flexible material such as PDMS; the upper layer substrate 1 and the lower layer substrate 2 are bonded, so that a closed fluid channel can be formed;
the upper substrate 1 comprises a micro-channel network; the micro-channel network comprises an enrichment channel 4, a detection channel 5 and an outlet channel 7; the upper-layer matrix 1 is also provided with a fluid inlet 3 and a fluid outlet 6;
one end of the enrichment flow channel 4 is connected with the fluid inlet 3, the other end of the enrichment flow channel is connected with the detection flow channel 5, and the detection flow channel 5 is connected with the fluid outlet 6 through the outlet flow channel 7; the fluid inlet 3 and the fluid outlet 6 are both communicated with the outside; the fluid inlet 3 and the fluid outlet 6 can be communicated with the outside by perforating the upper-layer matrix 1 or the lower-layer substrate 2;
an elastic cavity 8 is arranged above the outlet flow passage 7, and the elastic cavity 8 is connected with a pressure interface 9; the PDMS material between the outlet flow channel 7 and the elastic cavity 8 has elasticity; as shown in fig. 4;
the fluid inlet 3 and fluid outlet 6 may be connected to a fluid control system by capillary tubing; the fluid control system comprises a syringe pump and a pressure pump, wherein the fluid inlet 3 is connected with the syringe pump, and the fluid outlet 6 can be not connected with the pressure pump in the embodiment;
polyfunctional group linked molecules for capturing trace gas molecules are attached to the inner wall of the enrichment flow channel 4 through electrostatic adsorption; the multifunctional linker molecule comprises an electropositive group (such as a nitrogen-containing group), an aminoxy group and a thiol group;
the width of the flow channel in the micro-flow channel network is 5-500 μm, and the height is 5-500 μm;
preferably, the enrichment flow channel 4 can adopt a reciprocating bending or convolution configuration to form an enrichment area;
more preferably, the width of the detection flow channel 5 is larger than that of the enrichment flow channel 4, so as to form a detection area.
The detection process of the trace gas is as follows:
a Raman spectrum analysis detection device is arranged above the detection flow channel 5;
gas to be detected is introduced from the fluid inlet 3; the capture and enrichment of trace gas molecules are realized on the inner wall of the enrichment flow channel 4; the carbonyl compound in the trace gas and the aminoxy group in the polyfunctional group linked molecule can generate oximation reaction, so that the trace gas molecule can be captured;
introducing eluent from a fluid inlet 3 into an enrichment flow channel 4 and then into a detection flow channel 5; the eluent is liquid (such as deionized water or some organic solvent), has almost no SERS activity, and contains gold nanoparticles or silver nanoparticles with surfaces modified by thiol molecules, and is used for fixing the eluted trace gas molecules; for example, the surface of the gold nanoparticle modified by thiol molecules has thiol groups, and the thiol groups on the surface of the gold nanoparticle can further react with the oximation reaction product to fix the eluted gas molecules; part of the surface (without sulfydryl) of the gold nanoparticles can also form covalent chemical bonds with sulfydryl in the polyfunctional group linking molecule to realize fixation; double fixation is realized; the injection flow rate of the eluent is 0.01-0.5 mL/min;
then, performing Raman spectrum analysis on the detection flow channel 5; after detection, the liquid flows out from the fluid outlet 6;
on one hand, the nano gold particles or nano silver particles modified by mercaptan molecules can fix eluted gas molecules; on the other hand, the electric field at the nano metal particles is greatly enhanced, and the obvious Raman signal enhancement can be generated;
the micro-fluidic device can be repeatedly used, and before each use, polyfunctional group linked molecules for capturing trace gas molecules can be attached to the inner wall of the enrichment flow channel 4 through electrostatic adsorption.
Example three, as shown in fig. 3;
this embodiment proposes a micro-fluidic device that trace gas enrichment and detection function are integrated, includes: an upper substrate 1 and a lower substrate 2 bonded to each other;
wherein the upper layer matrix 1 is made of PDMS material and can transmit light; the material of the lower substrate 2 can be a hard material such as glass and organic glass, and can also be a flexible material such as PDMS; the upper layer substrate 1 and the lower layer substrate 2 are bonded, so that a closed fluid channel can be formed;
the upper substrate 1 comprises a micro-channel network; the micro-channel network comprises an enrichment channel 4, a detection channel 5 and an outlet channel 7; the upper-layer matrix 1 is also provided with a fluid inlet 3 and a fluid outlet 6;
one end of the enrichment flow channel 4 is connected with the fluid inlet 3, the other end of the enrichment flow channel is connected with the detection flow channel 5, and the detection flow channel 5 is connected with the fluid outlet 6 through the outlet flow channel 7; the fluid inlet 3 and the fluid outlet 6 are both communicated with the outside; the fluid inlet 3 and the fluid outlet 6 can be communicated with the outside by perforating the upper-layer matrix 1 or the lower-layer substrate 2;
the fluid inlet 3 and fluid outlet 6 may be connected to a fluid control system by capillary tubing; the fluid control system comprises a syringe pump and a pressure pump, wherein a fluid inlet 3 is connected with the syringe pump, and a fluid outlet 6 is connected with the pressure pump;
polyfunctional group linked molecules for capturing trace gas molecules are attached to the inner wall of the enrichment flow channel 4 through electrostatic adsorption; the multifunctional linker molecule comprises an electropositive group (such as a nitrogen-containing group), an aminoxy group and a thiol group;
the width of the flow channel in the micro-flow channel network is 5-500 μm, and the height is 5-500 μm;
preferably, the enrichment flow channel 4 can adopt a reciprocating bending or convolution configuration to form an enrichment area;
preferably, the width of the detection flow channel 5 is greater than that of the enrichment flow channel 4, so as to form a detection area;
the detection process of the trace gas is as follows:
a Raman spectrum detection device is arranged above the detection flow channel 5;
gas to be detected is introduced from the fluid inlet 3; the capture and enrichment of trace gas molecules are realized on the inner wall of the enrichment flow channel 4; the carbonyl compound in the trace gas and the aminoxy group in the polyfunctional group linked molecule can generate oximation reaction, so that the trace gas molecule can be captured;
introducing eluent from a fluid inlet 3 into an enrichment flow channel 4 and then into a detection flow channel 5; the eluent is liquid (such as deionized water or certain organic solvents) but does not contain nano gold particles or nano silver particles with the surfaces modified by thiol molecules; trace gas molecules captured by the inner surface of the enrichment flow channel can be flushed into the eluent; the injection flow rate of the eluent is 0.01-0.5 mL/min; in the detection flow channel 5, gold is coated on the surface of the magnetic bead 10, and the surface of the gold-coated magnetic bead is modified by thiol molecules, so that eluted trace gas molecules can be fixed; for example, the surface of the gold-coated magnetic bead has sulfydryl after being modified by thiol molecules, and the sulfydryl on the surface of the gold-coated magnetic bead can further react with an oximation reactant and is used for fixing eluted gas molecules; part of the surface (without sulfydryl) of the gold-coated magnetic bead can also form covalent chemical bonds with sulfydryl in the polyfunctional group linking molecule to realize fixation; double fixation is realized; since the blocking of the magnetic beads can cause the reduction of the liquid flow rate, the eluent containing trace gas molecules can be fully contacted with the magnetic beads; so that the enriched trace gas molecules are fully combined with the gold and the sulfydryl on the surface of the magnetic bead;
the liquid pressure between the fluid inlet 3 and the fluid outlet 6 is balanced by the fluid control system, and the trace gas molecules stay in the detection flow channel 5;
then, performing Raman spectrum test and analysis on the detection flow channel 5; after detection, the liquid flows out from the fluid outlet 6;
after the surfaces of the gold-coated magnetic beads are modified by mercaptan molecules, the eluted gas molecules can be fixed; on the other hand, the electric field on the surface of the gold-coated magnetic bead is greatly enhanced, so that remarkable Raman signal enhancement can be generated;
the micro-fluidic device can be repeatedly used, and before each use, polyfunctional group linked molecules which can be used for capturing trace gas molecules can be attached to the inner wall of the enrichment flow channel 4 through electrostatic adsorption.
Example four;
the fourth embodiment provides a method for preparing a microfluidic device integrating functions of trace gas enrichment and detection, which comprises the following steps:
spin-coating a layer of SU-8 negative photoresist on a silicon wafer, and forming a mold with a micro-channel network on the silicon wafer through a photoetching process; the thickness of the negative photoresist is larger than that of the upper-layer matrix 1 to be manufactured;
preparing a PDMS material and a curing agent, for example, the proportion of PDMS to the curing agent is 10:1, pouring the PDMS material on a mould, and stripping PDMS from a silicon wafer after curing to obtain an upper-layer matrix 1 with a micro-channel network;
punching holes on the upper-layer matrix 1 to realize the communication between the fluid inlet 3 and the fluid outlet 6 with the outside;
carrying out oxygen plasma treatment on the flow channel surface of the upper-layer matrix 1 and the lower-layer substrate 2, for example, placing the flow channel surface and the lower-layer substrate in a plasma cleaning machine for oxygen plasma bombardment to realize flow channel surface silanization and negative charge; then bonding the flow channel surface of the upper substrate 1 with the lower substrate 2;
introducing a polyfunctional group linking molecular solution with electropositive groups (such as nitrogen-containing groups), aminoxy groups and mercapto groups into the flow channel, drying at a certain temperature, and performing electrostatic adsorption to realize the modification of the inner surface of the flow channel; the polyfunctional group linked molecules are adsorbed on the inner surface of the flow channel through electrostatic action;
for the magnetic beads 10 in the third embodiment, the magnetic beads 10 coated with gold and having surfaces modified by thiol molecules may be filled before the upper substrate 1 is bonded to the lower substrate 2; the size of the magnetic beads 10 should be larger than the width of the outlet channel 7 to avoid flowing out of the detection zone during elution.
Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to examples, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.
Claims (3)
1. A trace gas enrichment and detection method is characterized by comprising the following steps:
introducing gas to be detected from the fluid inlet (3); polyfunctional group link molecules for capturing trace gas molecules are attached to the inner wall of the enrichment flow channel (4) through electrostatic adsorption; the capture and enrichment of trace gas molecules are realized on the inner wall of the enrichment flow channel (4); the multifunctional linking molecule comprises an electropositive group, an aminoxy group and a mercapto group;
introducing eluent from a fluid inlet (3) into an enrichment flow channel (4) and then into a detection flow channel (5); the eluent is liquid and contains nano gold particles with surfaces modified by mercaptan molecules and is used for fixing the eluted trace gas molecules; the surfaces of the gold nanoparticles modified by mercaptan molecules have sulfydryl, and the sulfydryl on the surfaces of the gold nanoparticles reacts with oximation reaction products to fix eluted gas molecules; part of the surface of the gold nanoparticles, namely part of the surface without sulfydryl, and sulfydryl in the polyfunctional group linked molecule form covalent chemical bonds to realize fixation; thereby realizing double fixation;
controlling so that the liquid pressure between the fluid inlet (3) and the fluid outlet (6) is equalized and the eluent carries the trace gas molecules to stay in the detection flow channel (5);
and then carrying out Raman spectrum analysis on the detection flow channel (5).
2. A trace gas enrichment and detection method is characterized by comprising the following steps:
introducing gas to be detected from the fluid inlet (3); polyfunctional group link molecules for capturing trace gas molecules are attached to the inner wall of the enrichment flow channel (4) through electrostatic adsorption; the capture and enrichment of trace gas molecules are realized on the inner wall of the enrichment flow channel (4); the multifunctional linking molecule comprises an electropositive group, an aminoxy group and a mercapto group;
introducing eluent from a fluid inlet (3) into an enrichment flow channel (4) and then into a detection flow channel (5); the eluent is liquid and contains nano gold particles with surfaces modified by mercaptan molecules and is used for fixing the eluted trace gas molecules; the surfaces of the gold nanoparticles modified by mercaptan molecules have sulfydryl, and the sulfydryl on the surfaces of the gold nanoparticles reacts with oximation reaction products to fix eluted gas molecules; part of the surface of the gold nanoparticles, namely part of the surface without sulfydryl, and sulfydryl in the polyfunctional group linked molecule form covalent chemical bonds to realize fixation; thereby realizing double fixation;
pressure gas is accessed through a pressure interface (9), the material between the elastic cavity (8) and the outlet flow channel (7) generates elastic deformation, the outlet flow channel (7) is closed, and the eluent carries trace gas molecules to stay in the detection flow channel (5);
and then carrying out Raman spectrum analysis on the detection flow channel (5).
3. A trace gas enrichment and detection method is characterized by comprising the following steps:
introducing gas to be detected from the fluid inlet (3); polyfunctional group link molecules for capturing trace gas molecules are attached to the inner wall of the enrichment flow channel (4) through electrostatic adsorption; the capture and enrichment of trace gas molecules are realized on the inner wall of the enrichment flow channel (4); the multifunctional linking molecule comprises an electropositive group, an aminoxy group and a mercapto group;
introducing eluent from a fluid inlet (3) into an enrichment flow channel (4) and then into a detection flow channel (5); the eluent is liquid and does not contain nano gold particles with the surfaces modified by thiol molecules; causing the trapped trace gas molecules to be flushed into the eluent; a magnetic bead (10) is arranged in the detection flow channel (5), the surface of the magnetic bead (10) is coated with gold, the surface of the gold-coated magnetic bead is modified by thiol molecules, and the surface of the gold-coated magnetic bead has sulfydryl; the gold and the sulfydryl on the surface of the magnetic bead (10) carry out double fixation on the eluted trace gas molecules, and the double fixation specifically comprises the following steps: the sulfydryl on the surface of the gold-coated magnetic bead reacts with an oximation reactant and is used for fixing eluted gas molecules; part of the surface of the gold-coated magnetic bead, namely, part of the surface without sulfydryl also forms covalent chemical bonds with sulfydryl in the polyfunctional group linking molecule to realize fixation; thereby realizing double fixation;
controlling such that the liquid pressure between the fluid inlet (3) and the fluid outlet (6) is balanced and the trace gas molecules stay in the detection flow channel (5);
and then carrying out Raman spectrum analysis on the detection flow channel (5).
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