Microfluidic chip and method for simultaneously enriching double gas-phase free radicals by using the same

Abstract

A microfluidic chip for simultaneous enrichment of gas phase carbon free radicals and peroxide free radicals belongs to the technical field of microfluidic chips and comprises a glass substrate and channels etched on the substrate, including a sample channel, a carrier gas channel, a mixed gas channel, a photochemical reaction meander array structure channel and a partition enrichment channel. The sample channel is used for sample gas delivery; the carrier gas channel is used for reaction gas delivery; the mixed gas channel is a meander structure channel and is used for mixing of sample gas and reaction gas; the photochemical reaction meander array structure channel is arranged in an axial symmetry mode by multiple single meander structure channels and is used as a gas phase photochemical reaction area; and the partition enrichment channel is used for collection of gas phase free radical adducts. The present application can realize simultaneous enrichment of double gas phase free radicals, improve detection efficiency, and the meander array structure channel design has a high specific surface area, effectively improves the content of gas phase free radical adducts and improves enrichment performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of environmental monitoring and microfluidic chip technology, in particular to a microfluidic chip for simultaneous enrichment of gas-phase carbon radicals and peroxy radicals. BACKGROUND

[0002] Gas-phase radicals play a crucial role in atmospheric chemistry, as active participants in various chemical reactions, they play a key role in processes such as ozone generation, formation and decomposition of air pollutants. Free radicals have high reactivity, usually reacting with other molecules to form new radicals or products, thereby triggering a series of complex chemical reactions. Studying the transformation process of gas-phase radicals helps to reveal the formation, transformation and removal mechanism of pollutants in the atmosphere.

[0003] Due to its high activity, gas-phase radicals are difficult to detect by direct detection method. Therefore, a trapping agent is usually used to capture and form stable radical adducts for further detection. However, the current gas-phase radical capture method is mostly achieved by blowing gas into the trapping agent solution, which is easily affected by the solvent molecules in the liquid phase environment, and cannot truly reflect the information of gas-phase radicals.

[0004] Microfluidic technology, as an advanced technology for precise control and manipulation of fluids at the micron scale, provides a new way to overcome the above limitations. The micron-scale size of the microfluidic channel matches the diffusion distance of the radical intermediate, so that the gas-phase radicals can quickly react with the trapping agent in the microchannel within the diffusion distance after generation, thereby achieving efficient enrichment of extremely low concentration gas-phase radicals. In addition, the microfluidic platform can accurately regulate fluid behavior and reaction environment, realizing real-time monitoring of the dynamic changes of radicals and overcoming the shortcomings of traditional methods. SUMMARY

[0005] To solve the problems existing in the prior art, the present application provides a microfluidic chip for simultaneous enrichment of gas-phase carbon radicals and peroxy radicals, which can realize efficient enrichment of gas-phase radicals.

[0006] To achieve the above technical purpose, the present application provides the following technical scheme:

[0007] A microfluidic chip for simultaneous enrichment of gas-phase carbon radicals and peroxy radicals, comprising a glass substrate and a channel etched on the substrate, the channel comprising a sample channel (1), a carrier gas channel (2), a gas mixing channel (3), a photochemical reaction meandering array structure channel (4), and a partition enrichment channel (5).

[0008] The sample channel (1) is a tree-shaped channel, which is divided into two branch channels from one channel, and is used for sample gas delivery.

[0009] The carrier gas channel (2) has two carrier gas channels for conveying the reaction gas;

[0010] The gas mixing channel (3) has two gas mixing channels, each of which is a meandering structure channel, and the meandering structure channel is a curved channel formed by connecting multiple "U" type channels together for mixing the sample gas and the reaction gas;

[0011] The photochemical reaction meandering array structure channel (4) is composed of multiple single meandering structure channels arranged in a symmetrical manner; the photochemical reaction meandering array structure channel (4) is connected by n meandering array channels, n is an odd number, preferably n is an odd number of 3-11; each section is composed of multiple meandering structure channels in parallel; from the first section to the (n+1) / 2 section, the number of meandering structure channels in each section gradually increases, from the (n+1) / 2 section to the n section, the number of meandering structure channels in each section gradually decreases, and the whole forms a symmetrical structure with the (n+1) / 2 section as the symmetry center; straight pipe connecting pipes are arranged on both sides of the photochemical reaction meandering array structure channel (4) and between the sections, the straight pipe connecting pipes are in communication with the corresponding connected meandering structure channels, and the straight pipe connecting pipes are perpendicular to the length direction of the meandering structure channels; the multiple meandering structure channels in each section are in parallel structure; the two sides are the initial side and the terminal side.

[0012] The photochemical reaction meandering array structure channel (4) has two photochemical reaction meandering array structure channels, each of which is connected in communication with the terminal end of a gas mixing channel (3) at the initial side, and each of which is connected in communication with the partition enrichment channel (5) at the terminal end;

[0013] The partition enrichment channel (5) has two partition enrichment channels, each of which is a single channel. They are respectively used for collecting gas phase carbon radical adducts and peroxide radical adducts.

[0014] The terminal end of each carrier gas channel (2) is respectively connected in communication with the initial end of a gas mixing channel (3), and the terminal end of each gas mixing channel (3) is respectively connected in communication with the initial side of a photochemical reaction meandering array structure channel (4);

[0015] The terminal end of each branch channel of the sample channel (1) is respectively connected in communication with the initial end of a gas mixing channel (3);

[0016] Preferably, the carrier gas channel, the gas mixing channel, the photochemical reaction meandering array structure channel, and the partition enrichment channel are all provided with two parts for simultaneously enriching double gas phase radicals on the same microfluidic chip.

[0017] Preferably, the channel section of the sample channel, carrier gas channel, mixed gas channel, photochemical reaction meander array structure channel, and partition enrichment channel is oval or circular, and the cross-sectional diameters are the same.

[0018] Furthermore, the sample channel, carrier gas channel, and partition enrichment channel are connected with an external fused quartz capillary for the entry of relevant gas and the pumping of relevant solution.

[0019] Preferably, the substrate is made of quartz glass to ensure that photochemical reactions are carried out.

[0020] Channel etching uses a hydrofluoric acid wet etching method, and chip substrate bonding uses a thermal bonding method.

[0021] The method for simultaneous enrichment of double gas-phase free radicals using the above microfluidic chip system comprises the following steps:

[0022] S1: Pump the solution of carbon radical capture probes through one partition enrichment channel (5) into one photochemical reaction meander array structure channel (4) and stand for a period of time; pump the solution of peroxide radical capture probes through another partition enrichment channel (5) into another photochemical reaction meander array structure channel (4) and stand for a period of time; to ensure that the two kinds of free radical capture probe solutions can fully cover the inner walls of the respective photochemical reaction meander array structure channels;

[0023] S2: Use inert gas to blow out the free radical capture agent solution in the photochemical reaction meander array structure channel (4) through the partition enrichment channel (5), so that each free radical capture agent is uniformly coated on the inner wall of the corresponding photochemical reaction meander array structure channel (4);

[0024] S3: Sample gas enters two mixed gas channels (3) through the sample channel (1), while one carrier gas channel (2) passes into one reaction gas into one mixed gas channel (3) to mix with the sample gas, and then enters the corresponding photochemical reaction meander array structure channel (4); at the same time, one carrier gas channel (2) passes into another reaction gas into another mixed gas channel (3) to mix with the sample gas, and then enters the corresponding another photochemical reaction meander array structure channel (4); in each photochemical reaction meander array structure channel (4), the gas undergoes photolysis to generate free radicals, and the generated free radicals are immediately captured by the free radical capture agent coated on the inner wall of the photochemical reaction meander array structure channel (4) to generate corresponding carbon radical capture adducts and peroxide radical capture adducts;

[0025] S4: the elution solution is pumped into the photochemical reaction meander array structure channel (4) through the sample channel (1) and the two carrier gas channels (2), so as to elute the radical capture adducts attached to the inner wall of the photochemical reaction meander array structure channel (4), and the eluted solution continues to flow through the two independent partition enrichment channels (5), so as to complete the collection of the two gas phase radical adducts.

[0026] Further, the sample gas is selected from methyl propyl aldehyde and the like, the carbon radical capture probe is selected from the NBD-T probe and the like, the peroxyl radical capture probe is selected from the H2B-TOH probe and the like, the reaction gas corresponding to the carbon radical capture probe is nitrogen gas, and the captured is a carbon radical; and the reaction gas corresponding to the peroxyl radical capture probe is oxygen gas, and the captured is a peroxyl radical.

[0027] From the above, compared with the prior art, the beneficial effects of the present application are as follows: (1) the present application can realize the simultaneous enrichment of double gas phase radicals, realize the miniaturization, integration and reduction of sample consumption of the device, and improve the detection efficiency by opening two gas phase photochemical reaction region systems on the quartz microfluidic chip;

[0028] (2) the meander array structure channel has high specific surface area, effectively improves the content of the radical adduct, and improves the enrichment performance. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0030] Figure 1 It is a front view of the present application, in which: (1) sample channel, (2) carrier gas channel, (3) gas mixing channel, (4) photochemical reaction meander array structure channel, (5) partition enrichment channel.

[0031] Figure 2 It is a gas phase carbon radical adduct mass spectrum.

[0032] Figure 3 It is a gas phase peroxyl radical capture adduct mass spectrum. DETAILED DESCRIPTION

[0033] The present application will be further described in detail below in combination with specific embodiments. Detailed embodiments and specific operation processes are given, and the embodiments will help to understand the present application, but the protection scope of the present application is not limited to the following embodiments.

[0034] The embodiment discloses a microfluidic chip for simultaneous enrichment of gas-phase carbon radicals and peroxide radicals, which comprises a quartz glass substrate and channels etched on the quartz glass substrate, and comprises a sample channel (1), a carrier gas channel (2), a mixed gas channel (3), a photochemical reaction meandering array structure channel (4), and a partition enrichment channel (5). Details are shown in the accompanying drawings Figure 1 The chip etching method is a wet etching method. After the sample channel (1), the carrier gas channel (2), the mixed gas channel (3), the photochemical reaction meandering array structure channel (4), and the partition enrichment channel (5) are etched by hydrofluoric acid, the channel section is an ellipse, and the channel diameter is 100 μm. The sample channel (1) is a tree-shaped structure channel, wherein the outer fused quartz capillary channel is 6.5 mm, the angle between the two branch sample channels is 150°, and the length is 8.36 mm. The carrier gas channel (2) is 8 mm long, wherein the outer fused quartz capillary channel is 6.5 mm long. The sample channel (1) and the carrier gas channel (2) converge and communicate with one side of the mixed gas channel (3). The mixed gas channel (3) is a meandering structure channel, which is connected together by a plurality of “U” type channels. This channel is used for mixing sample gas and reaction gas. The photochemical reaction meandering array structure channel (4) is connected together with the mixed gas channel (3) on one side and connected in communication with the partition enrichment channel (5) on the other side. The photochemical reaction meandering array structure channel (4) is arranged in an axisymmetric manner by 19 single meandering structure channels, that is, the photochemical reaction meandering array structure channel (4) is 5 sections, from the 1st section to the 5th section, the number of meandering channels is 3 / 4 / 5 / 4 / 3. The partition enrichment channel (5) is 6 mm long and is used for collecting gas-phase radical adduct samples. The etched carrier gas channel (2), mixed gas channel (3), photochemical reaction meandering array structure channel (4), and partition enrichment channel (5) of the microfluidic chip are provided in two parts, which are used for simultaneous enrichment of double gas-phase radicals on the same microfluidic chip. The chip quartz glass substrate is bonded by a hot bonding method. The sample channel (1), the carrier gas channel (2), and the partition enrichment channel (5) are bonded with the outer fused quartz capillary by epoxy glue, which is used for related gas entering and pumping related solutions. The outer fused quartz capillary channel is etched to a section diameter of 420 μm. The outer fused quartz capillary has an inner diameter of 100 μm, an outer diameter of 365 μm, and a length of 30 cm.

[0035] The embodiment method is applied to an actual environment, and the specific application is as follows:

[0036] S1: Select NBD-T probe that specifically captures carbon radicals and H2B-TOH probe that specifically captures peroxide radicals, and pump 400 μmol / L NBD-T probe solution and H2B-TOH radical probe solution into the corresponding photochemical reaction meander array structure channel (4) through two partition enrichment channels (5) capillary respectively. Then, stand for 10 minutes to ensure that the capture agent solution can uniformly and fully cover the inner wall of the channel.

[0037] S2: Insert the capillary of the two partition enrichment channels into the stainless steel sample bin, and insert the nitrogen quartz capillary with a flow rate of 15 mL / min into the sample bin. Nitrogen blows the two probe solutions out of the channel through the partition enrichment channel (5) capillary, thereby achieving uniform coating of the inner wall of the photochemical reaction meander array structure channel (4).

[0038] S3: Prepare three stainless steel sample bins, named A, B and C respectively, and place 80 μL of methylacrolein solution in the stainless steel sample bin A, and use oxygen and nitrogen for input reaction carrier gas in sample bin B and sample bin C; sample bin A is heated in a water bath to volatilize the reagent, and after the water bath is heated for 10 minutes, the sample bin A is filled with methylacrylate gas, then the capillary of the sample channel (1) and the nitrogen quartz capillary with a flow rate of 10 mL / min are inserted into the sample bin A, in the process, the capillary of one carrier gas channel (2) connected to the photochemical reaction meander array structure channel (4) coated with NBD-T probe is inserted into sample bin B with a nitrogen quartz capillary with a flow rate of 10 mL / min, and the capillary of the other carrier gas channel (2) connected to the photochemical reaction meander array structure channel (4) coated with H2B-TOH probe is inserted into sample bin C with an oxygen quartz capillary with a flow rate of 10 mL / min; this configuration can realize that the methylacrylate gas is mixed with nitrogen and oxygen respectively through the sample channel (1) and the two carrier gas channels (2) in the gas mixing channel (3), and the mixed gas enters the two groups of photochemical reaction meander array structure channel regions (4) for reaction;

[0039] S4: The quartz microfluidic chip of the present embodiment was placed under a mercury lamp for 2 min at 6A (current) conditions, and methylacrolein gas underwent photolysis reaction to generate various carbon radicals (obtained under nitrogen) and peroxyl radicals (obtained under oxygen) in the two groups of photochemical reaction regions, respectively, and the generated radicals were immediately captured by the two probes coated on the inner wall of the channel. S5: The mass spectrometry grade acetonitrile solution was sucked by a syringe, and the acetonitrile solution was pumped into the sample channel (1) capillary and two carrier gas channels (2) capillaries at a flow rate of 150 μL / min by means of a micro-injection pump to the photochemical reaction meander array structure channel (4), so as to elute the radical capture adducts attached to the inner wall of the chip channel, and the eluted solution continued to flow through two independent partition enrichment channels (5), so as to complete the collection of two gas phase radical adducts, and the collection of two gas phase radical adduct samples was performed for 1 min, followed by mass spectrometry detection. The experimental results are shown in Figure 2 As shown in FIG. 4, in the methylacrolein photolysis reaction, the NBD-T probe successfully captured three carbon radicals. Through high-resolution mass spectrometry analysis, in the negative ion mode (2500V), these adducts showed corresponding hydrogen reduction peaks, with mass-to-charge ratios of 402.1755, 362.1499 and 348.1659, respectively, and the signal intensity was relatively significant. Figure 3 As shown in FIG. 5, the H2B-TOH probe also effectively captured three peroxyl radicals. Through high-resolution mass spectrometry detection, in the positive ion mode (2500V), these radical adducts showed sodium addition peaks, with mass-to-charge ratios of 633.2510, 605.2588 and 579.2469, respectively, and the signal intensity was also relatively significant.

[0040] Through the method of the present embodiment, the simultaneous enrichment and detection of gas phase carbon radicals and peroxyl radicals in the methylacrolein system were successfully achieved.

[0041] The above merely describes the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes to the technical solutions and inventive concepts of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A microfluidic chip, characterized in that, The microfluidic chip is used for the simultaneous enrichment of gaseous carbon free radicals and peroxy free radicals. It includes a glass substrate and channels etched on the substrate. The channels include sample channels (1), carrier gas channels (2), mixed gas channels (3), photochemical reaction meandering array structure channels (4), and partitioned enrichment channels (5). The sample channel (1) is a tree-shaped channel, which is divided into two branch channels for sample gas delivery; Two carrier gas channels (2) are used to transport the reaction gas; There are two gas mixing channels (3), each of which is a meandering structure channel. The meandering structure channel is a curved channel made up of multiple "U"-shaped channels connected together, used for mixing sample gas and reaction gas. The photochemical reaction meandering array structure channel (4) is composed of multiple single meandering structure channels arranged symmetrically. The photochemical reaction meandering array structure channel (4) is composed of n segments of meandering array channels connected together, where n is an odd number. Each segment is composed of multiple meandering structure channels arranged in parallel. From the 1st segment to the (n+1) / 2nd segment, the number of meandering structure channels in each segment gradually increases, and from the (n+1) / 2nd segment to the nth segment, the number of meandering structure channels in each segment gradually decreases, forming a structure symmetrical about the (n+1) / 2nd segment. Straight pipes are provided on both sides and between segments of the photochemical reaction meandering array structure channel (4). The straight pipes are all connected to the corresponding meandering structure channels and are perpendicular to the length direction of the meandering structure channels. The multiple meandering structure channels in each segment are all in parallel. The two sides are the initial side and the end side. There are two photochemical reaction meandering array structure channels (4). The initial side of each photochemical reaction meandering array structure channel (4) is connected to the end of a gas mixing channel (3). The end side of each photochemical reaction meandering array structure channel (4) is connected to the partition enrichment channel (5). The partitioned enrichment channel (5) consists of two channels, each of which is a single channel; used to collect gaseous carbon radical adducts and peroxy radical adducts, respectively. Each gas carrier channel (2) is connected to the initial end of a gas mixing channel (3) at its end, and each gas mixing channel (3) is connected to the initial side of a photochemical reaction meandering array structure channel (4) at its end. Each branch of the sample channel (1) is connected to the initial end of a gas mixing channel (3).

2. A microfluidic chip for simultaneous enrichment of gaseous carbon free radicals and peroxy free radicals according to claim 1, characterized in that, The carrier gas channel, gas mixing channel, photochemical reaction meandering array structure channel, and partitioned enrichment channel are all divided into two parts for simultaneous enrichment of two-phase free radicals on the same microfluidic chip.

3. A microfluidic chip for simultaneous enrichment of gaseous carbon free radicals and peroxy free radicals according to claim 1, characterized in that, The sample channel, carrier gas channel, mixed gas channel, photochemical reaction meandering array structure channel, and partitioned enrichment channel have elliptical or circular cross-sections with the same diameter.

4. A microfluidic chip according to claim 1, characterized in that, The sample channel, carrier gas channel, and zone enrichment channel are all connected to an external fused silica capillary.

5. A microfluidic chip according to claim 1, characterized in that, The substrate is made of quartz glass to ensure the photochemical reaction proceeds.

6. A microfluidic chip according to claim 1, characterized in that, The channel etching uses hydrofluoric acid wet etching, and the chip substrate bonding uses thermal bonding.

7. A microfluidic chip according to claim 1, characterized in that, n is an odd number between 3 and 11.

8. A method for simultaneous enrichment of two-phase gaseous free radicals using a microfluidic chip according to any one of claims 1-7, characterized in that, Includes the following steps: S1: Pump the carbon radical capture probe solution into a photochemical reaction meandering array structure channel (4) through a partitioned enrichment channel (5) and let it stand for a period of time; pump the peroxide radical capture probe solution into another photochemical reaction meandering array structure channel (4) through another partitioned enrichment channel (5) and let it stand for a period of time; to ensure that the two radical capture probe solutions can fully cover the inner wall of their respective photochemical reaction meandering array structure channels; S2: Inert gas is used to blow out the free radical scavenger solution in the photochemical reaction meandering array structure channel (4) through the partition enrichment channel (5), so that each free radical scavenger is uniformly coated on the inner wall of its corresponding photochemical reaction meandering array structure channel (4); S3: The sample gas enters the two mixing channels (3) through the sample channel (1) and simultaneously... A carrier gas channel (2) is introduced into a mixed gas channel (3) to mix with the sample gas, and then enters the corresponding photochemical reaction meandering array structure channel (4); at the same time, a carrier gas channel (2) is introduced into another mixed gas channel (3) to mix with the sample gas, and then enters the corresponding photochemical reaction meandering array structure channel (4); in each photochemical reaction meandering array structure channel (4), the gas undergoes a photolysis reaction to generate free radicals, and the generated free radicals are then captured by the free radical scavengers coated on the inner wall of the photochemical reaction meandering array structure channel (4) to generate the corresponding carbon free radical capture adduct and peroxy free radical capture adduct; S4: The elution solution is pumped into the photochemical reaction meandering array structure channel (4) through the sample channel (1) and two carrier gas channels (2) to elute the free radical capture adducts attached to the inner wall of the photochemical reaction meandering array structure channel (4). The eluted solution continues to flow through two independent partitioned enrichment channels (5) to complete the collection of two gas phase free radical adducts.

9. The method according to claim 8, characterized in that, The sample gas was selected from methacrolein, the carbon radical capturing probe was selected from the NBD-T probe, the peroxy radical capturing probe was selected from the H2B-TOH probe, the reaction gas corresponding to the carbon radical capturing probe was nitrogen, which captures carbon radicals, and the reaction gas corresponding to the peroxy radical capturing probe was oxygen, which captures peroxy radicals.

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