Preparation method of colorimetric sensor for gas chromatography, product and gas analysis system

Abstract

The invention discloses a preparation method of a colorimetric sensor for gas chromatography, which comprises the following steps: dissolving dye by using a thin layer chromatography silica gel plate as a substrate and ethanol as a solvent to enable the dye to be attached to the substrate, and blow-drying. The invention also provides a gas analysis system which comprises a sample injection subsystem, a carrier gas subsystem, a capillary chromatographic separation column system, a colorimetric sensing subsystem and a data analysis subsystem. According to the invention, gas chromatography and a video data extraction program can be combined, the visual detection of a gas analyte sample can be conveniently realized, the miniaturization of a gas detection and analysis system is facilitated, and a new thought and direction are provided for the development of a miniature gas chromatograph detector.

Description

Technical Field

[0001] The present invention relates to the technical field of gas detection and analysis, and more specifically, to a preparation method and product of a colorimetric sensor for gas chromatography and a gas analysis system. Background Art

[0002] Gas chromatography (GC) is an analytical method that uses gas as a mobile phase. Through the interaction between the gasification of the analyte sample and the stationary phase, it can separate different components in a gas mixture in space and time. It has the advantages of high efficiency, high sensitivity, and a wide range of applications. It is widely used in the field of analysis and detection, especially in the analysis of volatile organic compounds (VOCs). Whether for a desktop or micro gas chromatograph, the performance of the detector largely determines the performance of the gas chromatograph. However, for most detectors, when the length of the chromatographic separation column is short, it is impossible to clearly distinguish the gas mixture, and it is difficult to accurately identify the target in a variety of gas mixtures, which greatly limits its application in micro gas chromatography. In addition, the volume of some traditional gas chromatograph detectors is too large, which restricts the miniaturization of the entire gas analysis system. At the same time, the colorimetric sensor element still has the problem of signal response saturation during continuous detection. Therefore, it is still necessary to solve or partially solve the above technical problems in order to provide new ideas and directions for the development of micro gas chromatograph detectors, and also provide an efficient and convenient detection method for fields such as gas analysis. Summary of the invention

[0003] The present invention provides a method for preparing a colorimetric sensor for gas chromatography, a product and a gas analysis system, which are combined with gas chromatography and a video data extraction program, are conducive to portable visualization detection of gas analyte samples, are conducive to the miniaturization of gas detection and analysis systems, and provide new ideas and directions for the development of micro gas chromatograph detectors.

[0004] In order to achieve these purposes and other advantages according to the present invention, there is provided a method for preparing a colorimetric sensor for gas chromatography, comprising: A thin layer chromatography silica gel plate is used as a substrate, and ethanol is used as a solvent to dissolve the dye, so that the dye adheres to the substrate and is blown dry.

[0005] Preferably, a spotting capillary is used to spot the dye on the substrate, so that the dye is attached to the substrate to form a circular dye spot, and a spot-type colorimetric sensor based on a single dye is prepared; or Using a spotting capillary to spot dyes on the edges of several substrates, so that different dyes are attached to each substrate, forming several arc-shaped dye spots bounded by the edges of the substrates, and then assembling them to form a circular dye spot to prepare a dot-type colorimetric sensor array based on different dye combinations; or The substrate is directly immersed in the dye container so that the dye is evenly spread on the silica gel plate, and the dye is attached to the substrate to form a dye surface, thereby preparing a plate-type colorimetric sensor based on the dye surface.

[0006] The colorimetric sensor for gas chromatography prepared by the preparation method.

[0007] Gas analysis system, including inlet subsystem, carrier gas subsystem, capillary chromatographic separation column system, The injection subsystem includes an injection port and a vaporization chamber, which are used to vaporize the analyte sample; The carrier gas subsystem includes a gas cylinder, a pressure gauge, a pressure valve, and a mass flow controller, and is used to deliver the vaporized sample into the capillary chromatographic separation column subsystem at a certain flow rate; The capillary chromatographic separation column subsystem comprises a capillary chromatographic separation column, which is used to separate vaporized samples; The gas analysis system further comprises: A colorimetric sensing subsystem, comprising the colorimetric sensor, wherein the dye dot of the colorimetric sensor is arranged at the outlet end of the capillary chromatographic separation column, and is used for identifying and detecting the vaporized sample; The data analysis subsystem includes a shooting device and a video data extraction program. The shooting device is used to shoot a video of the color information of the analyte identified by the colorimetric sensor, and the video data extraction program is used to convert the color information into digital information to generate the composition and content data of the analyte sample.

[0008] Preferably, the colorimetric sensing subsystem further comprises: The conveying structure includes a controller, a stepper motor driver, a stepper motor, and the conveyor belt. The conveyor belt is provided with a plate-type colorimetric sensor based on a dye surface. The controller drives the stepper motor through the stepper motor driver to rotate the conveyor belt, so that during the rotation of the conveyor belt, the outlet end of the capillary chromatographic separation column is periodically placed on the plate-type colorimetric sensor.

[0009] Preferably, the colorimetric sensing subsystem further comprises: A chromatographic device box, comprising an upper cover plate and a lower box body connected in an interlocking manner, wherein the colorimetric sensor is provided on the bottom surface of the lower box body; A horizontal shooting position, which is arranged on the upper cover plate, the horizontal shooting position has a placement surface of the shooting device, and the macro camera of the shooting device faces the colorimetric sensor; An irradiation site, which is arranged on the upper cover plate, and the irradiation site is provided with a light source facing the colorimetric sensor; A capillary chromatographic separation column fixed nesting site is arranged on the side wall of the lower box body, and the capillary chromatographic separation column fixed nesting site is provided with a damping shaft holder, a damping shaft, and a capillary chromatographic separation column holder. The damping shaft is rotatably installed on the chromatographic device box through the damping shaft holder, and the capillary chromatographic separation column holder enables the outlet end of the capillary chromatographic separation column to be adjacent to the dye point of the colorimetric sensor at a certain contact angle and contact distance through the damping shaft.

[0010] Preferably, when the colorimetric sensor is a point-type colorimetric sensor based on a single dye, the capillary chromatographic separation column is fixed so that the outlet end of the capillary chromatographic separation column is placed at a certain contact angle and contact distance to the dye point of the point-type colorimetric sensor; When the colorimetric sensor is a point-type colorimetric sensor array based on different dye combinations, the capillary chromatographic separation column is fixed, and the position of the point-type colorimetric sensor array is adjusted so that the outlet end of the capillary chromatographic separation column is simultaneously placed on a circular dye spot composed of multiple dyes at the same contact angle and contact distance.

[0011] Preferably, when the colorimetric sensor is a plate-type colorimetric sensor based on a dye surface, the bottom surface of the lower box is replaced by a transmission belt, and the plate-type colorimetric sensor is arranged on the transmission belt to fix the capillary chromatographic separation column so that the outlet end of the capillary chromatographic separation column is periodically placed on the plate-type colorimetric sensor at a certain contact angle and contact distance.

[0012] Preferably, the video data extraction program runs as follows: RGB color data of any selected area is extracted at a time interval of one second until the entire video captured by the camera is completely processed; an area of ​​any shape is drawn by brush strokes, and the size of the area is displayed in real time on the back end of the program in the form of the number of pixels; the extracted data is displayed as the average color of the area; the screen is moved to find the reaction area, and the RGB color data of the selected area in the video is extracted.

[0013] Preferably, the capillary chromatographic separation column is composed of 5% phenyl and 95% polydimethylsiloxane, has a length of 2 m, and the analyte sample is a volatile amine gas organic compound.

[0014] The present invention has at least the following beneficial effects: First, the present invention provides a method for preparing a colorimetric sensor for gas chromatography and a product thereof. A thin layer chromatography silica gel plate is used to prepare the colorimetric sensor. The sensor is prepared by coating a dye on its surface using its high adsorption and chemical stability. The preparation method is low-cost and simple in process. The colorimetric sensor can be miniaturized and made portable. The colorimetric sensor is particularly suitable for visual gas analysis and detection.

[0015] Second, the present invention provides a gas analysis system that innovatively combines a dye-based colorimetric sensor with a desktop gas chromatograph, integrating an inlet subsystem, a carrier gas subsystem, a capillary chromatographic separation column subsystem, a colorimetric sensor subsystem and a data analysis subsystem. The separated vaporized sample is identified and detected by a colorimetric sensor to achieve visual analysis of the gas.

[0016] Third, the point-type colorimetric sensor based on a single dye realizes the miniaturization of the detector by spotting on the substrate, and can be used for the analysis and detection of analyte samples. The point-type colorimetric sensor array based on different dye combinations can more easily integrate the dyes into the array mode by spotting on the edge of the substrate. Different dyes and target gases produce a composite response mode, which greatly reduces the dead volume of the gas in contact with the colorimetric sensor and improves the detection accuracy. The plate-type colorimetric sensor based on the dye surface solves the problem of irreversible or saturated reaction in mobile detection and realizes the visual analysis of the detection of multiple high-concentration gas samples.

[0017] Fourth, by providing a chromatographic device box, the present invention can achieve stable placement of the capillary chromatographic separation column at a certain contact angle and contact distance, create a detection environment, and help control the detection environment factors without interference, which is conducive to the portable and visual analysis and detection of analyte samples.

[0018] Fifth, the present invention runs a video data extraction program to determine the response signal between the colorimetric sensor and the analyte sample by calculating the difference between the red, green, and blue (R, G, B) color values ​​observed before and after the dye is exposed to the capillary chromatographic separation column to separate the analyte sample, reflecting the interaction process between the colorimetric sensor and the gas, so that the high-resolution video format shot can be displayed on a low-resolution computer screen, thereby realizing the distinction and identification of the analyte sample as a unique optical "fingerprint".

[0019] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of a colorimetric sensor according to a technical solution of the present invention; Figure 2 A schematic diagram of a gas analysis system according to a technical solution of the present invention; Figure 3 A diagram showing the operation steps of a video data extraction program according to a technical solution of the present invention; Figure 4 A schematic diagram of the structure of a chromatography device box according to a technical solution of the present invention; Figure 5 A chromatogram comparison diagram of the detection of analyte samples by various methods according to an example of the present invention; Figure 6 This is a chromatogram comparison diagram of the detection of analyte samples by various methods according to another example of the present invention. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0022] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0023] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified, and therefore should not be construed as limitations on the present invention.

[0024] The detection of volatile amine compounds has multiple meanings. Ensuring food safety: Volatile amine compounds are widely present in food, such as some health products may contain unlabeled amine substances. Excessive intake of these substances may pose a potential threat to health. By detecting these ingredients, it is possible to ensure that the content of amine substances in food and medicine is within a safe range and protect the health of consumers. Environmental protection: Volatile organic compounds (VOCs) have a serious impact on the environment and human health. Volatile gas detectors are of great significance in environmental protection. They can monitor the concentration of VOCs in various pollution sources in real time, assess environmental risks, guide pollution prevention and control, promote clean production, protect public health, and improve the level of environmental management. Industrial production: In the process of industrial production, the detection of volatile amine compounds can help enterprises optimize production processes, reduce pollutant emissions, and achieve sustainable development. By real-time monitoring of VOCs emissions in the production process, enterprises can take effective pollution prevention and control measures to reduce harm to the environment and human body. Health impact: Volatile amine compounds have a direct impact on human health. For example, the higher the volatile basic nitrogen content, the lower the nutritional value of the food. Excessive nitrogen content may cause food spoilage, gastrointestinal discomfort or even food poisoning after consumption. The present invention provides a colorimetric sensor and a gas analysis system for gas chromatography, which can perform specific analysis and detection of volatile amine gas organic compounds.

[0025] The present invention provides a method for preparing a colorimetric sensor for gas chromatography, comprising: A thin layer chromatography silica gel plate glass material is used as a substrate, and ethanol is used as a solvent to dissolve the dye, which can be chlorophenol red, so that the dye is attached to the substrate, for example, the dye is evenly spotted or spread on the substrate using a spotting capillary, and blown dry, for example, the substrate is blown dry with a hot air gun.

[0026] In the above technical solution, thin layer chromatography silica gel plate is used to prepare colorimetric sensor, which takes advantage of the high adsorption and chemical stability of thin layer chromatography silica gel plate, and is conducive to the interaction between colorimetric sensor and analyte sample. Ethanol is used as solvent for dissolution, which is conducive to enhancing the solubility of dye and its low boiling point and high volatility can be easily removed by hot air gun drying. The preparation method of colorimetric sensor is conducive to low-cost and miniaturized preparation of colorimetric sensor, and is conducive to the portable and visual analysis and detection of gas.

[0027] like Figure 1 As shown, the preparation method of the present invention can prepare a point-type colorimetric sensor based on a single dye, prepare a point-type colorimetric sensor array based on a combination of different dyes, and prepare a plate-type colorimetric sensor based on a dye surface. Specifically: (1) A spotting capillary is used to spot a dye on a substrate 101, so that the dye adheres to the substrate 101 to form a circular dye spot 102, thereby preparing a spot colorimetric sensor based on a single dye.

[0028] The single dye-based spot colorimetric sensor achieves miniaturization and low-cost preparation of the detector by spotting samples on a substrate, and can be used for analytical detection of analyte samples.

[0029] (2) using a spotting capillary to spot dyes on the edges of several substrates, so that different dyes are attached to each substrate, forming several arc-shaped dye spots bounded by the edge of the substrate, and then assembling them to form a circular dye spot. For example, spotting is performed on the left edge of a substrate to form an arc-shaped dye spot 103 bounded by the edge of the substrate, and spotting is performed on the right edge of another substrate to form an arc-shaped dye spot 104 bounded by the edge of the substrate, thereby preparing a dot-type colorimetric sensor array based on different dye combinations; The number of substrates is not limited to two, and can be interlocked in a circular area as needed to form a colorimetric sensor array containing different dye dots of multiple dyes. The dot colorimetric sensor array based on different dye combinations can more easily integrate the dyes into the array pattern by spotting on the edge of the substrate. Different dyes and target gases produce a composite response pattern, which greatly reduces the dead volume of the gas in contact with the colorimetric sensor and improves the detection accuracy. For a variety of target gases with similar properties, a variety of different dyes are used to produce a composite response pattern with the target gas, which serves as a unique optical "fingerprint" to distinguish and identify the gas, such as the formation of specific chemical interactions between dyes and gas molecules, including covalent bonds or ionic bonds, coupling, Lewis acid-base and π-π interactions.

[0030] (3) Directly immerse the substrate 105 in the dye container so that the dye is evenly spread on the silica gel plate, so that the dye adheres to the substrate to form a dye surface, and a plate-type colorimetric sensor based on the dye surface is prepared. When applied to fixed detection, the detector can also be miniaturized and prepared at low cost, and can be used for analytical detection of analyte samples. In order to avoid the reaction saturation caused by continuous detection at the same position, resulting in the inability to detect continuously, it can also be applied to mobile detection. Due to the uniform movement of the substrate, the effect of dye base-gas response-dye base alternation is presented 106.

[0031] The present invention provides a gas analysis system, comprising: An inlet sample system, the inlet sample system comprising an inlet and a vaporization chamber, for vaporizing the analyte sample; A carrier gas subsystem, the carrier gas subsystem comprising a gas cylinder, a pressure gauge, a pressure valve, and a mass flow controller, and used to deliver the vaporized sample into the capillary chromatographic separation column subsystem at a certain flow rate, and the gas cylinder may be a nitrogen cylinder; A capillary chromatographic separation column subsystem, wherein the capillary chromatographic separation column subsystem comprises a capillary chromatographic separation column, which is used to separate vaporized samples. The environment where the capillary chromatographic separation column is located needs to be temperature controlled, and the gas separation can be better achieved by controlling the temperature of the capillary chromatographic separation column. A colorimetric sensing subsystem, comprising the colorimetric sensor, wherein the dye dot of the colorimetric sensor is arranged at the outlet end of the capillary chromatographic separation column, and is used for identifying and detecting the vaporized sample; Preferably, the colorimetric sensor is placed on a mobile colorimetric sensor subsystem, and further includes: a transmission structure, which includes a controller, a stepper motor driver, a stepper motor, and the conveyor belt. The controller can be an Arduino development board. A plate-type colorimetric sensor based on a dye surface is arranged on the conveyor belt. The controller drives the stepper motor through the stepper motor driver to rotate the conveyor belt, so that during the rotation of the conveyor belt, the outlet end of the capillary chromatographic separation column is periodically placed on the plate-type colorimetric sensor. The stepper motor is connected to the conveyor belt to drive the colorimetric sensor to move at a uniform speed. The Arduino is used to receive instructions from the host computer and output pulse signals through pins. The Arduino development board is connected to the stepper motor driver. The stepper motor driver receives the pulse signal and drives the motor to rotate. By sending different numbers of pulses per second and inputting high and low levels, the speed and rotation direction of the stepper motor are accurately controlled, and the conveyor belt movement is controlled to achieve mobile detection. In practical applications, the Arduino development board can control the plate-type colorimetric sensor to move at different speeds, so as to find a speed that is more conducive to detection.

[0032] The data analysis subsystem includes a shooting device and a video data extraction program. The shooting device is used to shoot a video of the color information of the analyte recognized by the colorimetric sensor. The shooting device can be a smart phone. The video data extraction program is used to convert the color information into digital information and generate composition and content data of the analyte sample, which is conducive to comprehensive and real-time observation of the interaction process between the colorimetric sensor and the gas and the result analysis.

[0033] Specifically, Figure 3 As shown, the video processing program "roi.py" is written in Python, and the video data extraction program runs as follows: Step 301: Extracting RGB color data of any selected area at a time interval of one second can help select any sensing area for color data extraction. This is because in video recording, there will be a variety of redundant information within the canvas, and the sensing area changes randomly with different experimental conditions. Therefore, it is written to be able to extract any area to facilitate the analysis of experimental data.

[0034] Step 302: Draw an area of ​​any shape by pen strokes, and display the area size in real time on the program backend in the form of the number of pixels; extract data and display it as the average color of the area; this can be helpful for flexibly sampling the sensing area according to the experimental conditions, and the shape of the sampling area is any hand-drawn graphic area, and can display the area size and the extracted data in real time on the program backend in the form of the average color of the area, which is helpful for strictly controlling the experimental conditions and the scientific shape and range of the area sampling.

[0035] Step 303: The high-resolution video format shot can be displayed on a low-resolution computer screen. The response area can be found by moving the screen by operating the "w, a, s, d" keys on the keyboard, and the RGB color data of the selected area in the video can be processed and extracted starting with "r".

[0036] In order to enable a computer with normal performance to quickly process high-resolution videos, the video canvas size can be cropped to reduce most of the useless pixel areas in the video to reduce the total number of pixels in the video. That is, the RGB color data of a fixed area can be quickly and accurately extracted or directly extracted from the original video by moving the canvas to the reaction area (related to the performance of the computer); for example, the computer screen parameter for video processing is 141.21 ppi. If the size of the extracted video area is 3 or 10 pixels, the corresponding physical area is 0.09706 mm. 2 and 0.3235 mm 2 .

[0037] Step 304: The entire video captured by the camera is completely processed, and the extracted data is finally saved in the form of an EXCEL table.

[0038] The combination of a smartphone and a video data extraction program is conducive to reflecting the interaction process between the colorimetric sensor element and the gas, and enables the high-resolution video format shot to be displayed on a low-resolution computer screen. Among them, the response signal between the colorimetric sensor and the analyte is determined by calculating the difference between the red, green, and blue (R, G, B) color values ​​observed before and after the dye is exposed to the mixture separated by the chromatographic column. The RGB color mode uses an 8-bit RGB color model to assign an intensity value in the range of 0 to 255 to the R, G, and B channels of each pixel in the image as a unique optical "fingerprint" to distinguish and identify the analyte sample.

[0039] In the above technical scheme, a gas analysis system is provided, which innovatively combines a dye-based colorimetric sensor with a desktop gas chromatograph to realize the identification of target gases in multiple mixed gases that are not completely separated after passing through a capillary chromatographic separation column. The gas analysis system integrates an inlet subsystem, a carrier gas subsystem, a capillary chromatographic separation column subsystem, a colorimetric sensor subsystem and a data analysis subsystem. The gas sample is separated by a capillary chromatographic separation column and the gas flowing out of the capillary chromatographic separation column is detected by a colorimetric sensor. The target gas in multiple mixed gases is highly selectively identified, thereby realizing visual analysis of the gas.

[0040] Furthermore, the dye-surface-based plate-type colorimetric sensor solves the problem of irreversible or saturated reaction in mobile detection. When continuously detecting multiple volatile amine gas organic compounds, the substrate is moved slowly and uniformly to avoid reaction saturation caused by continuous detection at the same position. Due to the movement of the substrate, the chromatogram will present a shape of noise signal-response signal peak-noise signal, thereby alleviating the defect that the colorimetric sensor cannot continuously detect multiple amine gases at a fixed position, and realizes the visual analysis of the detection of multiple volatile amine gas organic compounds. It can also realize the detection of multiple or high-concentration amine gases through colorimetric sensors.

[0041] In the specific use process, the colorimetric sensor is a point colorimetric sensor based on a single dye, a point colorimetric sensor array based on a combination of different dyes, and a plate colorimetric sensor based on a dye surface. The following are the situations: (1) When the colorimetric sensor is a point-type colorimetric sensor based on a single dye, the capillary chromatographic separation column is fixed so that the outlet end of the capillary chromatographic separation column is placed at a certain contact angle and contact distance to the dye point of the point-type colorimetric sensor.

[0042] (2) When the colorimetric sensor is a point-type colorimetric sensor array based on different dye combinations, the capillary chromatographic separation column is fixed, and the position of the point-type colorimetric sensor array is adjusted so that the outlet end of the capillary chromatographic separation column is simultaneously placed on the circular dye spot composed of multiple dyes at the same contact angle and contact distance.

[0043] (3) When the colorimetric sensor is a plate-type colorimetric sensor based on a dye surface, the bottom surface 505 of the lower box is replaced by a transmission belt, and the plate-type colorimetric sensor is arranged on the transmission belt to fix the capillary chromatographic separation column so that the outlet end of the capillary chromatographic separation column is periodically placed on the plate-type colorimetric sensor at a certain contact angle and contact distance.

[0044] In a specific example, if Figure 2 As shown, including: The high-pressure nitrogen cylinder 201 and the gas chromatograph 202 are connected in sequence through a gas pipeline. The high-pressure nitrogen cylinder 201 is used to provide high-purity nitrogen with a purity of 99.99% as the experimental carrier gas. The inherent accessory pressure valve is used to adjust the pressure in the separation column. The external mass flow meter is used to accurately measure the flow rate of the carrier gas, and the vaporized sample is loaded into the capillary chromatographic separation column. The entire gas path environment is preferably kept at a constant flow rate of 2.4 mL / min during the analysis and determination; The injection port and the vaporization chamber 203 and the capillary chromatographic separation column 204 are connected in sequence through a gas pipeline. The column oven controls the temperature of the environment where the capillary chromatographic separation column 204 is located. The temperature of the capillary chromatographic separation column 204 is controlled to better achieve gas separation. The setting temperature is optimal when 31° C. The capillary chromatographic separation column is composed of 5% phenyl and 95% polydimethylsiloxane, with a length of 2 m. The analyte sample is a volatile amine gas organic compound. The outlet end 205 of the capillary chromatographic separation column is connected to the colorimetric sensor 206; The colorimetric sensor 206 is placed on the conveying structure 208, and the controller is an Arduino UNO motherboard. For example, the number of pulses sent per second is 10.5, 21, and 84, which correspond to 0.2 mm / s, 0.3 mm / s, and 0.4 mm / s, respectively, and is used to control the conveyor belt to move at a uniform speed and direction as required; The smartphone macro camera integrated module 207 is placed directly above the colorimetric sensor 206. The focal length of the macro camera is 75 mm, and the distortion degree is -1%. The personal computer 209 is used to receive the video sent by the smart phone macro camera integrated module 207 and extract the video RGB color information, and convert the color information into digital information for analysis and processing by running the video data extraction program "roi.py".

[0045] The contact angle and contact distance between the outlet end of the capillary chromatographic separation column and the colorimetric sensor are related to the degree of interaction between the colorimetric sensor and the gas and the recording effect of the camera. Figure 4 As shown, the colorimetric sensing subsystem also includes: A chromatographic device box, comprising an upper cover plate 501 and a lower box body connected in an interlocking manner, wherein the upper cover plate 501 is used to place a shooting device (a smart phone equipped with a macro camera) and a (white) light source, and the lower box body is equipped with a chromatographic column holder with a damping shaft for adjusting the direction of a capillary chromatographic separation column, and the colorimetric sensor is installed on the bottom surface 505 of the lower box body; A horizontal shooting position 502, which is arranged on the upper cover plate 501, and the horizontal shooting position 502 has a placement surface of the shooting device, and the macro camera of the shooting device faces the colorimetric sensor, for example, directly above the sensor at a distance of 75 mm; An irradiation site 504, which is disposed on the upper cover plate 501, and the irradiation site 504 is provided with a light source facing the colorimetric sensor; A capillary chromatographic separation column fixed nesting site 503 is arranged on the side wall of the lower box body, and the capillary chromatographic separation column fixed nesting site 503 is provided with a damping shaft holder, a damping shaft, and a capillary chromatographic separation column holder. The damping shaft is rotatably installed on the chromatographic device box through the damping shaft holder. The capillary chromatographic separation column holder enables the outlet end of the capillary chromatographic separation column to be adjacent to the dye point of the colorimetric sensor at a certain contact angle and contact distance through the damping shaft. The optimal setting angle is 60° and the contact distance is 1 mm.

[0046] In the above technical scheme, the present invention, by setting up a chromatographic device box, can realize the stable placement of the capillary chromatographic separation column at a certain contact angle and contact distance, create a detection environment, which is conducive to controlling the detection environment factors from interference and is conducive to realizing portable and visual analysis and detection of analyte samples.

[0047] In one example, the volume ratio of the mixture is (a) methanol: (b) n-butylamine: (c) benzene: (d) N,N-dimethylbutylamine: (e) n-pentylamine: (f) N,N-dimethylamide: (g) n-octane: (h) n-hexylamine = 5000: 5: 10: 5: 10: 10: 10: 30. The point-type colorimetric sensor, plate-type colorimetric sensor and existing FID sensor prepared in the present application are applied to the analysis of the same analyte sample, all using 23 μm capillary chromatography for separation. The detection results are as follows: Figure 5 As shown, the separation chromatogram (G channel) of the point-type colorimetric sensor and the separation chromatogram (G channel) of the plate-type colorimetric sensor in mobile detection are respectively shown.

[0048] The point colorimetric sensor and plate colorimetric sensor prepared in this application are used, the dye is chlorophenol red, the chromatographic column is 23 μm, the injector is 230°C, the column flow rate is 2.4 mL / min, the column temperature is 80°C, the static injection volume of the point colorimetric sensor is 0.1 μL, and the mobile injection volume of the plate colorimetric sensor is 0.3 μL, where the speed of "mobile" is 0.1 mm / s. The universal FID detector used has a 23 μm chromatographic column, an injector is 230°C, a column flow rate is 2.4 mL / min, a column temperature is 80°C, and the injection volume is 0.1 μL.

[0049] From the separation chromatogram of the point colorimetric sensor, it can be seen that the colorimetric sensor accurately identified 4 small amounts of amine compounds mixed in 8 mixtures. From the separation chromatogram of the plate colorimetric sensor through mobile detection, it can be seen that the chromatogram presents the shape of noise signal-response signal peak-noise signal, which is easier to detect qualitatively and quantitatively, avoiding the problem of reaction saturation when detecting at the same point, and helping to detect a variety of volatile amine gas organic compounds. The mixed sample was analyzed with an FID detector. Due to the large response signal of the solvent methanol, the peaks of other substances were not obvious, and there were tailing and overlapping phenomena, making it impossible to identify and quantitatively analyze the target substance.

[0050] In another example, the volume ratio of the mixture is (1) methanol (solvent): (2) dimethylamine: (3) n-butylamine: (4) N,N-dimethylbutylamine: (5) n-pentylamine: (6) n-hexylamine: (7) benzene: (8) pyridine: (9) toluene: (10) N,N-dimethylformamide: (11) n-octane: (12) methyl sulfoxide: (13) n-hexanol = 5000: 5: 5: 10: 20: 20: 10: 10: 10: 30: 10: 10: 10, and a 2 m SE-54 capillary chromatography separation column (inner diameter 320 μm, average coating thickness 15 μm) is used. The existing FID sensor and the point-type colorimetric sensor prepared in this application are applied to the analysis of the same analyte sample. The detection results are as follows: Figure 6 As shown, the separation chromatogram of the universal FID detector (G channel) and the separation chromatogram of the point colorimetric sensor (G channel) are respectively shown.

[0051] The point colorimetric sensor prepared in this application is used, the dye is chlorophenol red, the column is 2 m SE-54 capillary chromatography separation column, the injector is 230°C, the column flow rate is 2.4 mL / min, the column temperature is 30°C, and the injection volume of the point colorimetric sensor is 0.1 μL. The universal FID detector is used, the column is 2 m SE-54 capillary chromatography separation column, the injector is 230°C, the column flow rate is 2.4 mL / min, the column temperature is 30°C, and the injection volume is 0.1 μL.

[0052] From the separation chromatogram of the spot colorimetric sensor, it can be seen that the solvent peak signal is large during FID detection, while the response signal of the target analyte is low and peak overlap occurs. The colorimetric sensor accurately identifies a small amount of amine compounds (2)-(6) mixed in 13 mixtures with 5 amines, without interference from solvents and other samples. Compared with the general FID detector, the high selectivity of the spot colorimetric sensor shows a huge advantage in the separation and detection of 5 amines in 13 mixtures on a 2 m SE-54 capillary chromatographic separation column, and has the potential to be applied in micro gas chromatographs. At the same time, specific detection can also be achieved in a shorter chromatographic column (2 m), which is more conducive to rapid analysis.

[0053] The length of the capillary chromatographic separation column is related to the speed of analysis time. The shortened length of the capillary chromatographic separation column is conducive to application in a micro-chromatograph, and the design difficulty of the system heating device is greatly reduced and it is conducive to the rapid analysis and detection of gas samples. When the length of the capillary chromatographic separation column in the present application is 2 m, the mixed gas can be quickly separated. Compared with the prior art that requires a capillary chromatographic separation column of tens of meters or even dozens of meters to achieve gas separation, the present application shortens the length of the capillary chromatographic separation column while shortening the separation time, thereby achieving accurate identification of targets in a variety of gas mixtures.

[0054] The number of devices and processing scales described here are used to simplify the description of the present invention. Applications, modifications and variations of the present invention will be obvious to those skilled in the art.

[0055] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A method for preparing a colorimetric sensor for gas chromatography, characterized in that: include: A thin layer chromatography silica gel plate is used as a substrate, and ethanol is used as a solvent to dissolve the dye, so that the dye adheres to the substrate and is blown dry.

2. The preparation method according to claim 1, characterized in that Using a spotting capillary to spot the dye on the substrate, so that the dye is attached to the substrate to form a circular dye spot, and a spot-type colorimetric sensor based on a single dye is prepared; or Using a spotting capillary to spot dyes on the edges of several substrates, different dyes are attached to each substrate to form several arc-shaped dye spots bounded by the edges of the substrates, which are assembled to form a circular dye spot to prepare a dot-type colorimetric sensor array based on different dye combinations; or The substrate is directly immersed in the dye container so that the dye is evenly spread on the silica gel plate, and the dye is attached to the substrate to form a dye surface, thereby preparing a plate-type colorimetric sensor based on the dye surface.

3. A colorimetric sensor for gas chromatography prepared by the preparation method according to claim 2.

4. A gas analysis system, comprising an inlet subsystem, a carrier gas subsystem, and a capillary chromatographic separation column subsystem, characterized in that: The injection subsystem includes an injection port and a vaporization chamber, which are used to vaporize the analyte sample; The carrier gas subsystem includes a gas cylinder, a pressure gauge, a pressure valve, and a mass flow controller, and is used to deliver the vaporized sample into the capillary chromatographic separation column subsystem at a certain flow rate; The capillary chromatographic separation column subsystem comprises a capillary chromatographic separation column, which is used to separate vaporized samples; The gas analysis system further comprises: A colorimetric sensor subsystem, comprising the colorimetric sensor according to claim 3, wherein the dye dot of the colorimetric sensor is arranged at the outlet end of the capillary chromatographic separation column for identifying and detecting the vaporized sample; A data analysis subsystem, comprising a camera and a video data extraction program, wherein the camera is used to capture a video of the color information of the analyte identified by the colorimetric sensor of claim 3, and the video data extraction program is used to convert the color information into digital information to generate composition and content data of the analyte sample.

5. The gas analysis system according to claim 4, characterized in that: The colorimetric sensing subsystem also includes: The conveying structure includes a controller, a stepper motor driver, a stepper motor, and the conveyor belt. The conveyor belt is provided with a plate-type colorimetric sensor based on a dye surface. The controller drives the stepper motor through the stepper motor driver to rotate the conveyor belt, so that during the rotation of the conveyor belt, the outlet end of the capillary chromatographic separation column is periodically placed on the plate-type colorimetric sensor.

6. The gas analysis system according to claim 4 or 5, characterized in that: The colorimetric sensing subsystem also includes: A chromatographic device box, comprising an upper cover plate and a lower box body connected in an interlocking manner, wherein the colorimetric sensor is provided on the bottom surface of the lower box body; A horizontal shooting position, which is arranged on the upper cover plate, the horizontal shooting position has a placement surface of the shooting device, and the macro camera of the shooting device faces the colorimetric sensor; An irradiation site, which is arranged on the upper cover plate, and the irradiation site is provided with a light source facing the colorimetric sensor; A capillary chromatographic separation column fixed nesting site is arranged on the side wall of the lower box body, and the capillary chromatographic separation column fixed nesting site is provided with a damping shaft holder, a damping shaft, and a capillary chromatographic separation column holder. The damping shaft is rotatably installed on the chromatographic device box through the damping shaft holder, and the capillary chromatographic separation column holder enables the outlet end of the capillary chromatographic separation column to be adjacent to the dye point of the colorimetric sensor at a certain contact angle and contact distance through the damping shaft.

7. The gas analysis system according to claim 6, characterized in that: When the colorimetric sensor is a point-type colorimetric sensor based on a single dye, the capillary chromatographic separation column is fixed so that the outlet end of the capillary chromatographic separation column is placed at a certain contact angle and contact distance to the dye point of the point-type colorimetric sensor; When the colorimetric sensor is a point-type colorimetric sensor array based on different dye combinations, the capillary chromatographic separation column is fixed, and the position of the point-type colorimetric sensor array is adjusted so that the outlet end of the capillary chromatographic separation column is simultaneously placed on a circular dye spot composed of multiple dyes at the same contact angle and contact distance.

8. The gas analysis system according to claim 6, characterized in that: When the colorimetric sensor is a plate-type colorimetric sensor based on a dye surface, the bottom surface of the lower box is replaced by a transmission belt, and the plate-type colorimetric sensor is arranged on the transmission belt to fix the capillary chromatographic separation column so that the outlet end of the capillary chromatographic separation column is periodically placed on the plate-type colorimetric sensor at a certain contact angle and contact distance.

9. The gas analysis system according to claim 4, characterized in that: The video data extraction program runs as follows: RGB color data of any selected area is extracted at a time interval of one second until the entire video captured by the camera is completely processed; an area of ​​any shape is drawn by brush strokes, and the size of the area is displayed in real time on the back end of the program in the form of the number of pixels; the extracted data is displayed as the average color of the area; the screen is moved to find the reaction area, and the RGB color data of the selected area in the video is extracted.

10. The gas analysis system according to claim 4, characterized in that The capillary chromatographic separation column is composed of 5% phenyl and 95% polydimethylsiloxane, has a length of 2 m, and the analyte sample is a volatile amine gas organic compound.

Images