CN112098388B - Preparation method and application for constructing micro-fluidic chip based on silver microsphere monolithic column - Google Patents
Preparation method and application for constructing micro-fluidic chip based on silver microsphere monolithic column Download PDFInfo
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Abstract
The invention provides a preparation method and application for constructing a microfluidic chip based on a silver microsphere monolithic column, wherein the preparation method comprises the following steps: preparing a silver microsphere solution, wherein the silver microsphere surface of the silver microsphere solution has nano silver particles and a nano pore structure; preparing a chip with a microfluidic channel, wherein the microfluidic channel is provided with a Raman detection area for filling a silver microsphere solution and is also used as an enrichment area and a detection area of a sample to be detected; and injecting the silver microsphere solution into a Raman detection area of the microfluidic channel chip, naturally depositing to obtain an integral column, and replacing a molecular sieve with silver microspheres as a filler of the integral column to obtain the integrated detection chip with the collection and detection functions. The chip prepared by the invention realizes the rapid quantitative detection of organic components such as environmental gas, respiratory gas, pesticide residue and the like, has the advantages of environmental friendliness, simplicity in operation, lower cost, high sensitivity and high flux, and has better application prospects in the fields of environmental monitoring, pesticide residue monitoring, biomedicine and the like.
Description
Technical Field
The invention relates to the cross application fields of the fields of material science, micro-nano processing, food safety, environment, biomedicine and the like, in particular to a preparation method and application for constructing a micro-fluidic chip based on a silver microsphere monolithic column.
Background
Food safety, air pollution and early prevention and screening of serious diseases are closely related to the life quality and health of modern people and are also important problems endangering life safety. A number of recent studies have shown that an increase in PM2.5 in haze is one of the major causes leading to an annual increase in the prevalence of lung cancer. The atmosphere contains a large amount of nitrogen-containing organic particles from automobile exhaust, chemical waste gas, oil smoke and the like, and can generate an irritant organic compound under the irradiation of strong sunlight ultraviolet rays, thereby being harmful to the health of people. Currently, the main means of detecting these gases is through chemical reactions and laser absorption. However, chemical reactions are generally slow, and as the concentration of the gas becomes low, the accuracy and precision of the gas reaction measurement becomes poor; the laser absorption method is a relatively hot method for gas detection at the present stage, and can realize multi-component remote sensing for detection at present, but the detection process is relatively complicated, the analysis of the multi-component is not perfect enough, the detection of the complex gas in the environment is easy to interfere, and the accuracy needs to be improved.
Volatile Organic Compounds (VOCs) in respiratory gases are closely related to pathologies in the human body. For example, the content of methyl mercaptan and dimethyl mercaptan in the exhaled air of 116 volunteers was determined by the Kaji Hirosh group using chromatographic techniques, confirming that the content of dimethyl alcohol (4.05. + -. 1.06ng/dL) was much higher in the samples of patients with cirrhosis than in the samples of healthy persons (1.54. + -. 0.09ng/dL) in the fasted state. The FDA has now approved the use of test respiratory gas C13Urea content to diagnose helicobacter pylori infections.
Cancer is one of the major diseases threatening the life safety of people, and the early diagnosis of tumor can effectively improve the 5-year survival rate of cancer. The detection of tumor markers of VOCs in respiratory gases is an emerging frontline area of research in medical diagnostics. Relevant studies prove that specific VOCs markers can be generated by in vitro culture of colon cancer cells, lung cancer cell lines (CALU-1), white blood cells and the like. The early screening of cancer can be realized by detecting the specific markers, and the method has the characteristics of no pain, easy collection of samples and the like and is concerned. The biological principles underlying the selection of VOCs as tumor markers are believed to be based on cell biology. The tumor generation and development is accompanied by gene or protein changes, so that cell membrane surface substances are overoxidized to release VOCs, gas exchange is generated between the VOCs and the lung through in vivo metabolism and blood circulation, and the VOCs enter a respiratory system, therefore, the change of cells or exhaled gas VOCs is collected and detected, the early screening of the tumor is realized, and the method has important significance for searching the occurrence and development of the cancer. The earliest use of exhaled breath analysis for cancer diagnostic testing was the h.j.o' neiiii research group, which studied the composition of VOCs in the exhaled breath of lung cancer patients in 1985. Then, similar reports are found for breast cancer, head and neck cancer, pancreatic cancer, prostate cancer, colorectal cancer, liver cancer, and the like. However, under the influence of different environments, regions, dietary habits and the like, a unified standard for cancer markers of the cancer-specific VOCs and a standardized method for analyzing the tumor markers of the cancer-specific VOCs cannot be established for clinical research.
At present, technologies such as a chromatography detection method, a mass spectrometry direct detection method, a spectrum analysis method (infrared, fluorescence, laser, raman spectroscopy and the like) and the like are mainly used for VOCs analysis, and the technologies are mainly completed by large-scale laboratory instruments. With the development of nanotechnology, an electrochemical gas sensor and a colorimetric sensor are constructed on the basis of the semiconductor property, the special luminous performance and the catalytic performance of a nanometer material. The resistance gas sensor and the like provide good technical support for screening and developing trace detection and device development of VOCs gas.
The surface-enhanced Raman scattering spectrum technology has the advantages of high sensitivity, high selectivity, rapidness and the like, and realizes accurate quantitative detection of trace small molecules and even single molecules. For example, Yunsheng Chen et al's 2016 ACS Nano' in Yunsheng Chen et al, prepared gold nanoparticles by in situ reduction of graphene oxide with hydrazine vapor as a Raman-Enhanced substrate to detect volatile organic compounds in the exhaled gas of Gastric Cancer Patients (Breath Analysis Based on Surface-Enhanced Raman Scattering Sensors Early and Advanced scientific Cancer Patents from health Persons), the result proves that the method can obviously distinguish the content of organic molecules in the exhaled gas of normal Persons and Gastric Cancer Patients, and has high sensitivity. In addition, an article for detecting a Lung Cancer gas marker by using a Surface Enhanced Raman Scattering method (Selective Surface Enhanced Raman Scattering for Quantitative Detection of long Cancer Biomarkers in nanoparticles @ MOF Structure) was published by Xuezhi Qiao et al in 2018 on Advanced Materials, which modifies a material ZIF-8 outside a super particle assembled by gold nanoparticles, can selectively enrich small molecules, and then realizes Detection of aldehyde gas molecules by detecting Raman signals of specific chemical bonds formed by reaction of particle Surface molecules and the aldehyde molecules, wherein the Detection lower limit can reach 10ppb, and the advantage of the Surface Enhanced Raman Scattering in gas Detection is also proved.
Through search, the chinese patent with application number 201310411036.4 discloses a preparation of microfluidic monolithic column chip and its application in raman detection, including: preparing a PDMS micro-fluidic chip, preparing a porous monolithic column solution, and preparing a microfluidic chip monolithic column; on the other hand, the patent discloses the application of the prepared microfluidic monolithic column chip, silver microsphere solution is injected into the microfluidic chip, the ultra-sensitive Raman real-time detection of a sample to be detected is realized by utilizing the enrichment and surface Raman enhancement effects of the silver microspheres, and the detection limit can reach 10-12M。
However, the above patents have the following disadvantages: in fact, glycidyl methacrylate is taken as a monomer, ethylene glycol dimethacrylate is taken as a cross-linking agent, di-n-octyl phthalate is taken as a pore-forming agent, an organic polymer monolithic column with a plurality of pores is prepared through polymerization reaction, and then silver microspheres are filled into the monolithic column for Raman detection. The preparation process of the technology is complicated, and simultaneously has interference on a lot of organic matters, the distribution of the silver microspheres is not uniform, the content is limited, and the detection sensitivity is greatly limited.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a preparation method and application for constructing a micro-fluidic chip based on a silver microsphere monolithic column.
The invention provides a preparation method for constructing a microfluidic chip based on a silver microsphere monolithic column, which comprises the following steps:
preparing a silver microsphere solution, wherein the surface of a silver microsphere of the silver microsphere solution is provided with nano silver particles and a nano pore structure, so that a Raman detection hot spot can be provided;
preparing a chip with a microfluidic channel, wherein the microfluidic channel is provided with a Raman detection area for filling a silver microsphere solution and is also used as an enrichment area and a detection area of a sample to be detected;
and injecting the silver microsphere solution into a Raman detection area of the microfluidic channel chip, obtaining an integral column through natural deposition, and adopting silver microspheres to replace a molecular sieve as a filler of the integral column to obtain the integrated detection chip with the collection and detection functions.
Preferably, the preparing of the silver microsphere solution comprises:
synthesizing silver microspheres by adopting a liquid phase reduction method: bovine serum albumin is taken as a template, and ascorbic acid is taken as a reducing agent; dropwise adding AgNO into bovine serum albumin solution3And (3) reacting the solution, then adding ascorbic acid to carry out reduction reaction, and controlling the synthesis temperature and the stirring speed to prepare the silver microsphere solution.
Preferably, the silver microsphere solution is synthesized by a liquid phase reduction method, wherein a magnetic stirrer is used for stirring in the reaction process, the stirring speed is 200rpm-800rpm, and the reaction temperature is 30-80 ℃.
Preferably, the silver microsphere solution, AgNO, is synthesized by adopting a liquid phase reduction method3The concentration of silver ion in the solution is 1. mu.M-1 mM, and the concentration of ascorbic acid is 0.5. mu.M-1M.
The invention provides an application of the silver microsphere monolithic column-based micro-fluidic chip,
the micro-fluidic chip is used for qualitatively and quantitatively detecting volatile organic gases contained in respiratory gases of atmospheric air, human bodies or living animal bodies, organic additives and pesticide residue organic molecules in food, and comprises the following steps:
aiming at the detection of volatile organic gases, a sample to be detected is brought into the monolithic column through high-purity argon, the high surface and high activity of silver microspheres are utilized to adsorb and enrich small molecules of organic gases of the sample to be detected, and Raman spectrum detection is carried out on the small molecules of the organic gases by adopting Raman spectrum;
aiming at the detection of organic additives and pesticide residue organic molecules in food, a sample to be detected is directly introduced into a micro-fluidic chip after preliminary treatment in the early stage, and the organic molecules are detected through Raman spectroscopy;
and drawing a standard curve for the sample to be detected, thereby realizing the qualitative and quantitative detection of the trace amount of the sample to be detected.
Compared with the patent with application number 201310411036.4 in the background art, the method directly selects the silver microspheres with high surface energy as the filling agent, does not add any organic matter as an auxiliary reagent, directly prepares the monolithic column, organically assembles the silver microspheres in the chip and provides a large amount of hot spots for Raman detection by the nanostructure on the surfaces of the silver microspheres, greatly improves the detection precision and sensitivity, and has simple preparation method and good reproducibility.
Compared with the prior art, the invention has at least one of the following beneficial effects:
according to the preparation of the micro-fluidic chip, the Raman enhancement substrate of the monolithic column is formed on the basis of the silver microspheres, the silver microspheres with Raman enhancement performance are selected to replace molecular sieves to serve as fillers of the monolithic column, and due to the particularity of the silver microspheres, the stacked Raman enhancement effect of the silver microspheres is more obvious, so that the monolithic column is formed to enrich and detect gas, double functions of enriching a sample to be detected and detecting are given to the monolithic column, and trace micromolecules are collected and quantitatively detected in one step.
The preparation method of the microfluidic chip is simple to operate, the production cost of the microfluidic chip is low, and the large-scale production and practical application are easy.
The application of the microfluidic chip provided by the invention does not need to modify silver microspheres when being used for Raman spectrum detection, can be used for label-free detection, and has no interference peak of other molecules.
The application of the microfluidic chip disclosed by the invention has the advantages that the Raman spectrum is a molecular fingerprint spectrum, so that the microfluidic chip has high specificity and identifiability and narrower bandwidth, and can realize the simultaneous detection of various molecules.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1a is SEM image of silver microspheres according to a preferred embodiment of the invention;
FIG. 1b is a SEM image of a multilayer stacked silver microsphere according to a preferred embodiment of the invention;
FIG. 2a is an infrared absorption spectrum of silver microspheres according to a preferred embodiment of the present invention;
FIG. 2b is a thermogravimetric analysis curve of silver microspheres according to a preferred embodiment of the present invention;
FIG. 3a is a nitrogen absorption and desorption curve according to a preferred embodiment of the present invention;
FIG. 3b is a pore size distribution of silver microspheres according to a preferred embodiment of the present invention;
FIG. 4a is a schematic diagram of a microfluidic chip according to a preferred embodiment of the present invention;
FIG. 4b is a schematic diagram of a microfluidic chip according to a preferred embodiment of the present invention;
FIG. 5a is a graph showing the effect of the increased signal with the thickness of the silver microspheres in the Raman reporter detection of R6G (monomolecular surface enhanced resonance Raman scattering spectrum) according to a preferred embodiment of the present invention;
FIG. 5b is a graph showing the relationship between the signal intensity and the thickness of silver microspheres in the case of using R6G (monomolecular surface enhanced resonance Raman scattering spectrum) as a Raman reporter molecule;
FIG. 6a is a Raman spectrum of the quantitative detection of different toluene gases according to a preferred embodiment of the present invention;
FIG. 6b is a quantitative curve obtained by detecting toluene gas according to a preferred embodiment of the present invention;
FIG. 7 is a Raman spectrum of different gases detected according to a preferred embodiment of the present invention;
FIG. 8 is a schematic diagram of an application of a microfluidic chip constructed based on a silver microsphere monolithic column according to a preferred embodiment of the present invention;
the scores in the figure are indicated as: 1 is a microfluidic channel, 101 is a sample injection port to be detected, 102 is a silver microsphere field filling inlet, and 103 is waste liquid recovery.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.
Example 1
The embodiment provides a preparation method for constructing a microfluidic chip based on a silver microsphere monolithic column, which comprises the following steps:
s1: the silver microsphere solution is prepared, and the silver microsphere surface of the silver microsphere solution has nano silver particles and a nano pore structure, so that a Raman detection hot spot can be provided.
S2: preparing a chip with a micro-fluidic channel, wherein the micro-fluidic channel is provided with a Raman detection area for filling silver microsphere solution and is also used as an enrichment area and a detection area of a sample to be detected;
s3: and injecting the silver microsphere solution into a Raman detection area of the microfluidic channel chip, naturally depositing to obtain an integral column, and replacing a molecular sieve with silver microspheres as a filler of the integral column to obtain the integrated detection chip with the collection and detection functions.
The micro-fluidic chip constructed by the silver microsphere monolithic column prepared by the embodiment can be used for VOCs micro-fluidic chips in environment or respiratory gas, and the silver microspheres with specific Raman enhancement effect are selected as fillers in the preparation method to prepare the micro-fluidic channel with the function of the monolithic column, so that gas collection and quantitative detection are realized in one step. The preparation of the microfluidic chip can adopt a liquid phase reduction method to synthesize silver microspheres, form Raman enhanced 'hot spots' by utilizing nano silver particles and a nano pore structure on the surfaces of the silver microspheres, and directly inject the Raman enhanced 'hot spots' into a microfluidic channel to be dried to form an integral column. After a sample to be detected is introduced into the microfluidic channel, molecules to be detected are adsorbed in the silver microspheres in the monolithic column, and the Raman signal of the gas molecules is enhanced. The silver microspheres have a micro-nano structure, a large number of Raman detection hot spots are provided, and simultaneously with the layer-by-layer stacking of the silver microspheres, the steric hindrance of the silver microspheres enables the silver microspheres to be loosely stacked in a whole column, the distance between different particles is further increased, and the Raman enhancement effect is further improved, as shown in fig. 5a, an effect diagram that the signal is enhanced along with the increase of the thickness of the silver microspheres is detected by taking R6G (monomolecular surface enhanced resonance Raman scattering spectrum) as a Raman reporter molecule, as shown in fig. 5b, a relation curve between the signal intensity and the thickness of the silver microspheres is detected by taking R6G (monomolecular surface enhanced resonance Raman scattering spectrum) as the Raman reporter molecule. In the preparation method, the monolithic column is embedded into the microfluidic chip, so that the detection system can finish the enrichment of the sample to be detected, and the trace analysis of the object to be detected can be realized by adopting portable Raman spectroscopy. The preparation of the micro-fluidic chip integrates a micro-nano processing technology, develops a novel micro-fluidic Raman detection chip, and realizes a new technology and a new method for rapidly enriching and rapidly and quantitatively detecting trace toxic organic micromolecules such as organic micromolecule gas, food (such as milk, tea leaves and the like), water pollution and the like. The method for preparing the microfluidic chip has the characteristics of high selection, simplicity in operation, low cost, suitability for large-scale production and use and the like, and has a good application prospect in the fields of environmental monitoring, biomedical diagnosis and the like.
Example 2
The embodiment provides a preparation method of silver microspheres, which comprises the following steps:
s10: and reducing silver nitrate by using bovine serum albumin BSA as a template and ascorbic acid as a reducing agent to prepare the silver microspheres.
1mL of AgNO with the concentration of 150umol/L is prepared3The solution was mixed with Ascorbic Acid (AA) solution and Bovine Serum Albumin (BSA) solution at a concentration of 0.5mg/mL, using deionized water as solvent and was freshly prepared before the reaction.
S11: 17.625mL of deionized water and 375uL of BSA solution were added to the reaction flask, the reaction flask was placed on a magnetic stirrer heated to 30 ℃ with a stirring speed set at 600rpm, and after 5 minutes of reaction, 1mL of the prepared AgNO was added to the reaction flask3And (3) after the solution is subjected to reaction for 30 minutes under the condition of keeping the temperature and the stirring speed unchanged, adjusting the rotating speed to 700rpm in advance, quickly adding 1mL of AA solution, observing that the solution is quickly changed into grey at the moment, adjusting the rotating speed back to 600rpm after 5 seconds, and reacting for 30 minutes under the condition of keeping the temperature and the rotating speed unchanged to obtain a grey suspension.
S12: the resulting suspension was centrifuged at 5000rpmAfter 5 minutes, the reaction mixture was washed repeatedly with deionized water 3 times, and the supernatant was decanted off each time to leave a precipitate. Finally, the obtained precipitate is re-dissolved by deionized water for later use to obtain a silver microsphere solution, and the prepared silver microsphere solution is shown in scanning electron microscope SEM images of a reference picture 1a and a reference picture 1b, and as can be seen from the SEM images, the silver microsphere is about 1um in size and relatively uniform in size, and consists of nano silver particles and nano holes on the surface of the silver microsphere. Referring to FIG. 2a, it can be seen that the black solid curve is the absorption peak of BSA solid, 1700-1600cm-1The region is due to the C ═ O stretching vibration absorption of the amino acid residue, while O-H and N-H are at 3400cm-1Has an absorption peak; the black dotted line is the infrared spectrum absorption peak of the silver microsphere, and the black dotted line is a flat curve which shows that the surface of the silver microsphere is basically free of organic functional groups, so that no pollution can be ensured in detection. Referring to fig. 2b, which is a thermogravimetric analysis curve of the silver microsphere prepared in this example, it can be seen from the graph that at 240 ℃ to 270 ℃, the curve is significantly decreased, which indicates that the organic BSA in the silver microsphere is calcined, and the total organic matter accounts for 1% by mass, which indicates that the synthesized silver microsphere contains a small amount of organic matter and is mainly coated on the surface of the silver microsphere. Referring to fig. 3a and 3b, which are graphs showing the specific surface area results of the silver microspheres prepared in this example, fig. 3a is a nitrogen absorption and desorption curve, it can be seen from fig. 3a that the absorption and desorption of the gas on the surfaces of the silver microspheres mainly depends on the surface physical adsorption, the properties and the states of the gas are not changed, the chip can be repeatedly used, fig. 3b is a pore size distribution of the silver microspheres, and it can be seen from fig. 3b that the diameters of the surface nanopores of the silver microspheres are 4.88nm to 30nm, and are mainly distributed around 5nm, and this interval can be just in the action range of the electrostatic magnetic field, so that a hot spot for raman detection is provided, and at the same time, a site for adsorption of small organic molecules can be provided.
In the above embodiment, the liquid phase reduction method is used to synthesize silver microspheres, and the silver microspheres are used as a raman-enhanced substrate to design and manufacture an integral column as a novel gas sensor, so that detection of different gases can be realized through raman spectroscopy.
Example 3
The embodiment provides a method for preparing a chip with a microfluidic channel, which designs and utilizes PDMS to prepare a monolithic column chip and comprises the following steps:
s20: drawing a chip sketch by using CAD, processing the chip sketch into a mask according to the sketch, obtaining a chip template by using photoetching, pouring a layer of PDMS colloid on the chip template, placing the chip template in a 75 ℃ oven, baking for 1-2 hours, and then waiting for PDMS solidification for later use.
S21: and (3) placing the solidified PDMS and the purchased quartz plate into a plasma cleaning machine for processing for 2 minutes, and then quickly taking out the PDMS and the purchased quartz plate to be bonded together to form a microfluidic channel, thereby obtaining the chip with the microfluidic channel. Referring to fig. 4a, which is a design diagram of a chip with a microfluidic channel, it can be seen that a curved microfluidic channel 1 is formed in the chip, and a sample injection port 101 for injecting a sample to be detected is arranged on the microfluidic channel 1; the microfluidic channel 1 is provided with a silver microsphere solution filling inlet 102 for injecting a silver microsphere solution; a waste liquid recovery 103 is arranged at the end of the microfluidic channel 1. Referring to fig. 4b, a physical diagram of a chip with microfluidic channels is shown.
Example 4
The embodiment provides an application of the microfluidic chip constructed based on the silver microsphere monolithic column in the above embodiment, and the application of the microfluidic chip to detecting toluene gas includes:
s40: and (3) carrying out preliminary treatment on the toluene solution in the previous stage, adding the toluene solution with different volumes into a Teflon air bag, introducing argon into the Teflon air bag until the Teflon air bag is full of argon, standing at room temperature until the liquid is completely volatilized to form a series of toluene gas with different concentrations for later use.
S41: the air bag filled with toluene gas is connected with the microfluidic chip after being transferred through the gas guide tube, the residual gas is absorbed by using a wash bottle of ethanol, the toluene gas is brought into the monolithic column through argon, the gas path is closed after the toluene gas is introduced for a certain time for detection, and the micromolecules of organic gas of toluene gas are adsorbed and enriched by utilizing the high surface and high activity of the silver microspheres.
S42: referring to fig. 8, raman spectroscopy is used to perform raman spectroscopy detection on the toluene gas, and the toluene gas is plotted in a standard curve manner, so that the trace qualitative and quantitative detection of the toluene gas is realized. Referring to FIG. 6a, it is a Raman spectrum diagram of quantitative detection of different toluene gases, and it can be seen from FIG. 6a that no organic absorption peak is exhibited on the chip when no toluene is added, indicating that the chip has no interfering substances; the characteristic peak intensity of the toluene is gradually enhanced along with the increase of the concentration of the toluene, and the toluene has good concentration dependence; referring to fig. 6b, it can be seen from fig. 6b that the concentration of toluene is positively correlated to raman intensity in a quantitative curve obtained by detecting toluene gas, and the experimental result shows that this method can realize qualitative and quantitative detection of toluene.
Example 5
The embodiment provides an application of the microfluidic chip constructed based on the silver microsphere monolithic column in the above embodiment, and the microfluidic chip is used for detection of different gases.
S50: carrying out preliminary treatment on a sample to be detected in the early stage: respectively adding the styrene, the toluene and the valeraldehyde solution into an air bag, introducing argon into the air bag until the air bag is full of argon, standing at room temperature until the liquid is completely volatilized to form styrene, toluene and valeraldehyde gas samples to be detected.
S51: and (3) introducing the styrene, the toluene and the valeraldehyde gas into the monolithic column through argon, introducing the styrene, the toluene and the valeraldehyde gas for a certain time, and then closing a gas path for detection, wherein the silver microspheres are used for adsorbing and enriching micromolecules of organic gas of the styrene, the toluene and the valeraldehyde gas with high surface and high activity. The chip can realize the trace detection of different gases, and organic micromolecules with better difference in chemical structure can not generate interference, and can realize the simultaneous detection of various organic micromolecules.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.
Claims (5)
1. A preparation method for constructing a microfluidic chip based on a silver microsphere monolithic column is characterized by comprising the following steps:
preparing a silver microsphere solution, wherein the surface of a silver microsphere of the silver microsphere solution is provided with nano silver particles and a nano pore structure, so that a Raman detection hot spot can be provided;
preparing a chip with a microfluidic channel, wherein the microfluidic channel is provided with a Raman detection area for filling a silver microsphere solution and is also used as an enrichment area and a detection area of a sample to be detected;
injecting the silver microsphere solution into a Raman detection area of the microfluidic channel chip, obtaining an integral column through natural deposition, and adopting silver microspheres to replace a molecular sieve as a filler of the integral column to obtain an integral detection chip with collection and detection functions;
the silver microspheres have a micro-nano structure, a large number of Raman detection hot spots are provided, and simultaneously, along with the layer-by-layer accumulation of the silver microspheres, the steric hindrance of the silver microspheres enables the silver microspheres to be loosely accumulated in the whole column, so that the distance between different particles is further increased, and the Raman enhancement effect is further improved.
2. The preparation method for constructing the microfluidic chip based on the silver microsphere monolithic column as claimed in claim 1, wherein the preparation of the silver microsphere solution comprises:
synthesizing silver microspheres by adopting a liquid phase reduction method: bovine serum albumin is taken as a template, and ascorbic acid is taken as a reducing agent; dropwise adding AgNO into bovine serum albumin solution3And (3) reacting the solution, then adding ascorbic acid to carry out reduction reaction, and controlling the synthesis temperature and the stirring speed to prepare the silver microsphere solution.
3. The preparation method of the microfluidic chip constructed on the basis of the silver microsphere monolithic column as claimed in claim 2, wherein the silver microsphere solution is synthesized by a liquid phase reduction method, wherein a magnetic stirrer is used for stirring in the reaction process, the stirring speed is 200rpm-800rpm, and the reaction temperature is 30 ℃ to 80 ℃.
4. The method for preparing a microfluidic chip based on silver microsphere monolithic column as claimed in claim 2, wherein the silver microsphere solution AgNO is synthesized by liquid phase reduction3The concentration of silver ion in the solution is 1. mu.M-1 mM, and the concentration of ascorbic acid is 0.5. mu.M-1M.
5. The application of the silver microsphere monolithic column prepared by the method of claim 1 in constructing a microfluidic chip,
the micro-fluidic chip is used for qualitatively and quantitatively detecting volatile organic gases contained in breathing gas of atmosphere, human bodies or living animal bodies, organic additives and pesticide residue organic molecules in food, and comprises the following steps:
aiming at the detection of volatile organic gases, a sample to be detected is brought into the monolithic column through high-purity argon, the high surface and high activity of silver microspheres are utilized to adsorb and enrich small molecules of organic gases of the sample to be detected, and Raman spectrum detection is carried out on the small molecules of the organic gases by adopting Raman spectrum;
aiming at the detection of organic additives and pesticide residue organic molecules in food, a sample to be detected is directly introduced into a micro-fluidic chip after preliminary treatment in the early stage, and the organic molecules are detected through Raman spectroscopy;
and drawing a standard curve for the sample to be detected, thereby realizing the qualitative and quantitative detection of the trace amount of the sample to be detected.
Priority Applications (1)
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