CN106596531B - A method and device for detecting volatile organic compounds - Google Patents

Abstract

The invention provides a method and device for detecting volatile organic compounds. Firstly, the metal porphyrin zinc (TPPZn) sensitive to ethanol and the tetraphenylporphine manganese chloride (OEPMncl) sensitive to ethyl acetate are selected to make the capture sensor of organic gas; The collected organic gas reacts completely with the color-sensitive material; finally, a visible/near-infrared spectrometer detection device is used to obtain the reflection spectrum of the reacted gas capture sensor, and a detection model for volatile organic compounds is established by combining the chemometric method. The method and device of the invention can realize the quantitative analysis of volatile organic compounds, can significantly improve the corresponding detection efficiency compared with traditional analysis methods, and is more suitable for on-site rapid detection and analysis.

Description

A method and device for detecting volatile organic compounds

technical field

The invention relates to detection technology and equipment for volatile organic compounds, in particular to a method and device for detecting volatile organic compounds by using color-sensitive sensor technology and visible/near-infrared spectrum technology.

Background technique

Volatile organic compounds (volatile organic compounds, VOCs) refer to organic compounds with a boiling point range between 50 and 260 °C, including: alcohols, acids, ammonia and esters, etc.; mainly derived from petrochemicals, automobile exhaust, home decoration, etc. Based on the above-mentioned characteristics, they are called the second most serious air pollutants after dust, so it is necessary to study the corresponding detection methods and develop corresponding detection equipment, which is very important for people's healthy life and environmental protection. also has a very important meaning.

Gas chromatography (GC), mass spectrometry (MS) and gas chromatography-mass spectrometry (GC-MS) are earlier technical means used to detect and analyze volatile organic compounds, which can identify and measure hundreds of basic gas components and volatile organic compounds. sexual organic compounds. However, the above-mentioned technology requires that the gas, liquid, and solid analyzed are stable at the operating temperature; the corresponding operating temperature should not exceed the vaporization temperature of the analyzed liquid and solid; in addition, the traditional bench-top instrument is too large to meet the on-site Real-time collection, online analysis and detection requirements.

For example, the patent application No. 201520488455.2 of "A Novel Improved Gas Chromatography Device for VOC Monitoring" discloses an improved version of the Gas Chromatography Device that includes four parts: cooling, heating, separation, and chamber. In this patent, the cavity part is provided with a peripheral plate and an inner cavity; the cooling part includes a fan, a tuyere sealing plate, an electromagnet, and a cooling air passage; the heating part uses a heating wire and is located at the front end of the fan; the separation part uses a capillary column, Located at the front end of the heating wire, although the device has accurate temperature control and good thermal insulation effect, the corresponding equipment is expensive and bulky, which is not conducive to on-site inspection.

A gas sensor is a device or device that can sense a certain gas and its concentration in the environment. It can convert information related to the type and concentration of the gas into an electrical signal for detection, monitoring and analysis. However, the research on gas sensors involves a wide range of areas and is difficult. It belongs to the interdisciplinary research field, and the development of gas-sensitive materials is difficult. The functions are relatively single, and most of them cannot detect the components of multiple gases with one instrument.

For example, the patent application No. 200710078560.9 of "a fiber optic gas sensor" discloses a fiber optic gas sensor including: incident light and outgoing optical fiber, reaction cell, metalloporphyrin solution, and the like. In this patent, the gas to be measured is added from the vent below the reaction cell, and the VOCs gas is easily soluble in organic solvents, so that the VOCs gas can fully react with the sensitive substances of the metalloporphyrin solution. Adding different metalloporphyrin solutions from the feeding port of the reaction tank can effectively detect a variety of target gases at the same time, which improves the detection sensitivity and application range to a certain extent, but consumes more porphyrin solutions and costs more. , At the same time, it is impossible to realize the quantitative analysis of VOCs.

Visible/near-infrared spectrum is an electromagnetic wave that includes the range of visible light (visible light, VIS) and near-infrared light (near-infrared, NIR). The corresponding wavelength range is 380-1700nm. The rapid detection of ingredients has been widely used in the field of food and agricultural product quality analysis, such as fruit, meat, poultry eggs, etc., but the analysis of volatile organic compounds is limited to the Fourier transform near-infrared (FT) in the laboratory. -NIR) detection, and the corresponding instruments are expensive, and online real-time analysis is difficult to achieve.

According to the reaction between the specific sensing color-sensitive material and the volatile organic compound to be detected, it can be used as a corresponding volatile organic compound capture sensor array to realize qualitative classification and quantitative analysis of the organic gas to be detected. Metalloporphyrins can undergo coordination reactions with organic gases, resulting in changes in their energy. This change, which can be characterized in the spectrum in the visible light range, is sufficient for the analysis and detection of organic gases.

For example, Qi Rubin, Yin Xin, etc., in the article "Near-infrared Spectral Quantitative Detection Method of Multi-Component Organic Gases", used the partial least squares modeling method to analyze the near-infrared spectrum (1620 ~ 1750nm) of the mixed gas of propane, propylene and toluene. Modeling analysis was carried out, but the near-infrared spectrometer used in this research is large in size, and the self-made sample cell is expensive, so it is not universal.

For example, Zhao Jiewen, Zhang Jian and others, in the article "Olfactory Visualization Technology and Its Differentiation of Five Chemical Substances", developed an olfactory visualization system for five common chemical substances such as ethanol, formaldehyde, ammonia, acetone, and acetic acid. In order to detect, although porphyrin compounds and hydrophobic pH indicators are used as color-sensitive materials, scanners are used as the detection equipment for color difference, and the quantitative analysis of organic compounds cannot be realized.

Therefore, it is of great practical significance to find a simple and fast method for detecting VOCs to meet the actual production needs. The present invention uses the metalloporphyrin printed and dyed on the substrate as a carrier to obtain the volatile gas of the organic compound, undergoes a coordination reaction with it, detects and analyzes its spectral changes before and after the reaction with the volatile gas of the organic compound through visible/near-infrared spectroscopy, and combines the corresponding Chemometric methods for rapid quantitative analysis of organic gases.

Contents of the invention

The purpose of the present invention is to provide a method and device for detecting volatile organic compounds based on color-sensitive sensor-visible/near-infrared spectroscopy technology, so as to realize rapid quantitative analysis of volatile organic compounds.

For the method and device of the present invention, the technical scheme specifically adopted is as follows:

A method for detecting volatile organic compounds based on color-sensitive sensor-visible/near-infrared spectroscopy technology, comprising the following steps:

Step 1, the production of gas capture sensors: After quantum chemical test calculations, spectral dynamic analysis, and combined with physical and chemical analysis experiments, the metalloporphyrin zinc TPPZn sensitive to ethanol and the tetraphenylporphine sensitive to ethyl acetate were screened out. Manganese chloride OEPMncl; two color-sensitive materials are dissolved in an organic solvent at a certain concentration, and a C2 reverse-phase silica gel plate is used as a color-sensitive material carrier; the color-sensitive material is fixed on the sensor carrier by capillary spotting method to form a 1 ×2 gas capture sensor array;

Step 2, Diffuse reflectance spectrum detection in the visible/near-infrared band region of the capture sensor: After the volatile organic compounds are effectively enriched in the gas collection chamber, they are carried into the reaction chamber by the carrier gas, and are fully integrated with the gas capture sensor placed on the top of the reaction chamber. Reaction; connect the tungsten-halogen light source with the visible/near-infrared spectrometer with a Y-shaped optical fiber; use the tungsten-halogen light source as the input light source to scan the sensor after capturing the gas; use the visible/near-infrared spectrometer to obtain the visible/near-infrared spectrometer of the sensor after capturing the gas Diffuse reflectance spectra in the near-infrared region;

Step 3, optimization analysis of the organic gas detection model: the standard normal variable transformation SNV is used to preprocess the visible/near-infrared spectral data, and the joint interval partial least square method si-PLS is used for modeling optimization analysis.

Further, in the fabrication of gas capture sensors in step 1, the porphyrins of various metal centers, push-pull electrons, and substituent groups are calculated by quantum chemistry, combined with ultraviolet spectral kinetic analysis, and finally combined with experimental verification, the selected ones that are sensitive to alcohol gases Metalloporphyrin zinc TPPZn and ester gas-sensitive tetraphenylporphine manganese chloride OEPMncl as a color-sensitive sensor-gas capture sensor for a visible/near-infrared spectroscopy device.

Further, for the color-sensitive material in step 1, metalloporphyrin zinc TPPZn and tetraphenylporphine manganese chloride OEPMncl are dissolved in dichloromethane solvent, and the diluted solution is 2.0 mg/mL; porphyrin compounds are printed and dyed in C2 The reverse silica gel plate has good diffusion and high stability; in the capillary spotting method, the two color-sensitive materials form circular spots with a diameter of about 0.2cm on the silica gel plate.

Further, in step 2, the effective enrichment lies in that the amount of organic compound is 8.0mL, and the gas collection time is 20min, so there is enough space and time to achieve the best volatilization effect; the full reaction lies in the fact that the carrier gas carries Enter the reaction chamber to fully contact with the sensor and react for 5 minutes.

Further, in step 2, the tungsten halogen light source is a multi-purpose light source with a lifespan of up to 10,000 hours, and is suitable for a visible/near-infrared wavelength range of 360nm-2000nm; the visible/near-infrared wavelength range is in the range of 360nm-1200nm , the built-in filter holder is 50.8 square millimeters, and the thickness is 3.0mm, which can effectively obtain the visible/near-infrared region band; the stability of the input light source is that the output stability of the tungsten halogen lamp is 0.15% (peak-to-peak ), the drift is less than 0.3% per hour.

Further, in step 2, the visible/near-infrared spectrometer is small in size and easy to carry; the spectrometer module has a wavelength range of 300nm to 1100nm, covering visible and near-infrared regions; the grating of the spectrometer is 600 lines/mm, and the optical resolution The rate is 1.5nm FWHM, and the scanning spectrum information is better.

Further, in step 3, the detection model of the organic gas is the detection model of ethanol and the detection model of ethyl acetate; .45nm], [1002.76nm 1025.7nm] in four wavelength intervals, the model correlation coefficient is higher, and the stability is better; ], [749.21nm 775.76nm], [802.64nm 828.55nm] four wavelength intervals, the model correlation coefficient is higher and the stability is better.

The technical scheme of device of the present invention is:

A device for detecting volatile organic compounds based on color-sensitive sensor-visible/near-infrared spectroscopy technology, including a gas capture sensor device and a visible/near-infrared spectrometer detection device;

In the gas capture sensor device, nitrogen is used as the carrier gas; the carrier gas enters the device from the carrier gas inlet; the carrier gas inlet is connected to the valve A through the carrier gas pipeline; the valve A is connected to the gas collection chamber through the carrier gas pipeline The gas collection chamber is connected to the valve; in the gas collection chamber, a certain distance is maintained between the inlet pipe and the surface of the organic liquid, between the outlet pipe and the top of the gas collection chamber; the valve is connected to the reaction chamber inlet connected; a gas capture sensor is placed on the top of the reaction chamber; the gas outlet of the reaction chamber is connected to the exhaust gas collection ball through the carrier gas pipeline;

In the visible/near-infrared spectrometer detection device, the stage and the object support are fixed; the object stage, the object support and the Y-type optical fiber probe end are placed in the black box operating room; the probe end of the Y-type optical fiber The incident fiber end of the Y-shaped fiber is connected with a tungsten-halogen light source to obtain a stable light source input; the reflection fiber end of the Y-shaped fiber is connected with a visible/near-infrared spectrometer to obtain a color The reflectance spectrum of the visible/near-infrared region of the sensitive material; the visible/near-infrared spectrometer is connected to a computer through a data line to operate the corresponding spectrometer software in real time to obtain the spectral data of the sensing array.

Further, the gas capture sensor device is provided with a carrier gas cleaning pipeline and a carrier gas carrying volatile organic compound pipeline; the carrier gas cleaning pipeline is equipped with a valve A and a valve B; the valve A and the valve When B is fully opened for the first time, the pipeline is in a clean state, and when it is fully opened for the second time, the volatile organic compounds in the gas collection chamber enter the reaction chamber and react with the gas capture sensor under the carrier gas; Keep a distance of 1.0 cm between the pipe and the surface of the organic liquid, and keep a distance of 0.5 cm between the outlet pipe and the top of the collection chamber to fully carry the organic gas in the gas collection chamber.

Further, in the visible/near-infrared spectrometer detection device, the stage is a cylindrical base with a diameter of 10.0 cm and a height of 1.0 cm; the height of the carrier is adjustable, up to 15.0 cm; the dark box operation room is For a cube carton with a side length of 80.0cm, the door opening at the center of the front is 30.0cm*40.0cm; the Y-shaped optical fiber probe end is kept at a distance of 0.3cm from the stage in the dark box operation room, and can effectively contact the Color-sensitive circular spot; the diameter of the color-sensitive circular spot is 0.2 cm, completely covering the light spot at the end of the Y-shaped optical fiber probe.

The beneficial effects of the present invention are as follows:

First, for the production of gas capture sensor arrays: through quantum chemical test calculations, spectral dynamic analysis and physical and chemical analysis experiments, the metal porphyrin zinc (TPPZn) sensitive to ethanol and the tetraphenyl porphyrin sensitive to ethyl acetate were screened out. Porphine manganese chloride (OEPMncl), the capture sensor of making organic gas;

Second, for the enrichment and capture operation of volatile organic compounds: the organic compounds to be detected adopt a fixed amount and gas collection time, which can have enough space and time to achieve a better volatilization effect; the volatilized organic compounds The gas, carried by nitrogen as the carrier gas, can fully react with the gas capture sensor in the reaction chamber;

Third, for the spectral detection operation of the sensor after capturing the gas: irradiate the reacted gas capturing sensor with a multifunctional tungsten halogen light source, and the input light source signal is stable; the spectrometer in the visible/near-infrared band region can detect and capture Reflectance spectral data of the sensor array behind the organic gas;

Fourth, the optimization analysis of the organic gas detection model: After preprocessing the visible/near-infrared spectral data with the standard normal variable transformation (SNV), the combined interval partial least squares method (si-PLS) is used for modeling optimization analysis; For the detection model of ethanol, when the four wavelength intervals of [371.15 401.68], [402.68 432.3], [829.18 854.45], [1002.761025.7] are combined, the model correlation coefficient is higher and the stability is better; For the detection model, when the four wavelength intervals of [371.15 401.68], [666.64 694.15], [749.21 775.76], and [802.64 828.55] are combined, the model has a high correlation coefficient and good stability;

Fifth, for the gas capture sensor device: it is equipped with a carrier gas cleaning pipeline and a carrier gas carrying volatile organic compound pipeline, which can effectively collect the content of volatile organic compounds; A certain distance is maintained between the outlet pipe and the top of the collection chamber, which can fully carry the organic gas in the gas collection chamber to react with the gas capture sensor array;

Sixth, for the visible/near-infrared spectrometer detection device: according to the characteristics of the gas capture sensor array after the reaction, a matching loading bracket and dark box operation room were made; a Y-shaped optical fiber was used to connect the tungsten-halogen light source and the visible/near-infrared spectrometer , the collected spectral information can be transmitted to the computer terminal in real time to realize online monitoring of organic gas content.

Description of drawings

Fig. 1 is a schematic diagram of a 1 × 2 gas capture sensor of the present invention;

Fig. 2 is a schematic diagram of the experimental device of the present invention; (a) is a schematic diagram of a gas capture sensor device; (b) is a schematic diagram of a visible/near-infrared spectrum detection device;

Fig. 3 is the si-PLS detection model of TPP-Zn to ethanol;

Figure 4 is the si-PLS detection model of ethanol gas in the mixed gas of ethanol and ethyl acetate by TPP-Zn.

In the figure: 1 valve A, 2 gas collection chamber, 3 valve B, 4 gas capture sensor, 5 reaction chamber, 6 exhaust gas collection ball, 7 stage, 8 object support, 9 black box operation room, 10Y type optical fiber, 11 Halogen tungsten light source, 12 data connection lines, 13 visible/near-infrared spectrometers.

Detailed ways

The technical solutions of the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. The invention has universality for quantitative detection of volatile organic compounds. The target gases selected in this implementation case belong to two different low-toxic and relatively less harmful VOCs, namely ethanol and ethyl acetate. Other types of volatile organic compounds can be referred to this example.

In this implementation case, two color-sensitive materials with high sensitivity and high reliability are selected; gas capture sensor devices are used to capture volatile organic compounds in the reaction chamber; visible/near-infrared spectrometer detection devices are used to detect the sensors after capturing gases The reflection spectrum data of the array can achieve the purpose of rapid quantitative analysis. The specific technical scheme is as follows:

1. The manufacturing process of the gas capture sensor array of the present invention is as follows:

Through quantum chemical calculation of porphyrins with various metal centers, push-pull electrons and substituent groups, combined with ultraviolet spectral kinetic analysis, and finally combined with experimental verification, two porphyrin compounds were screened out, namely metal porphyrin zinc (TPPZn), Tetraphenylporphine manganese chloride (OEPMncl). The two color-sensitive materials used in the present invention can respectively react with alcohols and esters volatile organic compounds to produce color changes with different intensities, and have good selectivity and sensitivity.

The porphyrin compounds were dissolved in dichloromethane solvent respectively, and the two color-sensitive materials were printed and dyed on the _C2 reverse silica gel plate one by one through the micro-spotting capillary to form a 1×2 gas capture sensor array as shown in Figure 1.

2. The organic gas detection operation process of the present invention is as follows:

Before capturing the organic gas, the carrier gas (nitrogen) directly enters the reaction chamber 5 at a flow rate of 80mL/min to keep the sensor in a stable state; stop the inflow of nitrogen, close valve A 1 and valve B 3, and take 8mL test sample in the gas The collection chamber 2 is airtight and kept in this state for 20 minutes, so that the organic compound can achieve a better volatilization effect; open the valves A 1 and B 2 in turn, and switch the carrier gas to the flowing state, so that the test sample can be kept in a constant temperature and humidity environment. , as the carrier gas is carried into the reaction chamber 5 to react with the gas capture sensor 4, the reaction is sufficient after contacting for 5 minutes.

Before the detection of the visible/near-infrared spectrometer starts, the halogen light source 11 is connected to 220V AC and preheated for 30 minutes, the probe end of the Y-shaped optical fiber 10 is connected to the loading bracket 8 and fixed at a certain height, and the incident optical fiber end of the Y-shaped optical fiber 10 is connected to the halogen lamp The light source 11 and the reflective fiber end of the Y-shaped optical fiber 10 are connected to a visible/near-infrared spectrometer 13 , and the visible/near-infrared spectrometer 13 is connected to a computer through a data transmission line 12 . Open the corresponding visible/near-infrared spectrometer 13 operating software, set the integration time to 20 ms, the smoothness to 5 points, and the average number of scans to be ₅ times, and perform corresponding dark correction and white correction; take out the reacted C in the gas capture sensor device. Place the silica gel plate on the stage 7, align the probe end of the Y-shaped optical fiber 10 with the circular spot of the color-sensitive material on the silica gel plate, and collect the reflection spectra of the two color-sensitive materials in sequence, and record it as the captured color of the current sample. Spectral values of sensitive materials.

3. The establishment and optimization analysis method of the organic gas detection model of the present invention is as follows:

The collected visible/near-infrared spectrum contains noise information, background drift, etc., and it is necessary to use chemometric methods to establish a multiple regression model for analysis and prediction. The present invention uses a visible/near-infrared spectrometer to measure the reflectance spectra of volatile organic compounds-ethanol and ethyl acetate after capturing and sensing, and uses standard normal variable transformation (SNV) to preprocess the spectral data, and the combined interval partial minimum square Multiplication (si-PLS) was used to screen variables and model the spectral data to quantify the content of organic gases.

4. The device for detecting organic gases based on color-sensitive sensor-visible/near-infrared spectrum technology of the present invention is as follows:

As shown in Figure 2(a), it is a gas capture sensor device, which mainly includes a valve A 1, a gas collection chamber 2, a valve B 3, a gas capture sensor 4, a reaction chamber 5, and an exhaust gas collection ball 6. Wherein, nitrogen is used as the carrier gas and enters the device from the carrier gas inlet; the carrier gas inlet is connected to the valve A 1 through the carrier gas pipeline; the valve A 1 is connected to the gas collection chamber 2 through the carrier gas pipeline; the gas collection chamber 2 is connected to the valve 3; In the gas collection chamber 2, a certain distance is maintained between the inlet pipe and the surface of the organic liquid and the outlet pipe and the top of the gas collection chamber 2; the valve 3 is connected to the inlet of the reaction chamber 5; the gas capture sensor 4 is placed on the top of the reaction chamber 5; The gas outlet of the reaction chamber 5 is connected with the tail gas collecting ball 6 through the carrier gas pipeline.

As shown in Figure 2(b), it is a visible/near-infrared spectrometer detection device, which mainly includes an object stage 7, an object support 8, a black box operating room 9, a Y-shaped optical fiber 10, a tungsten-halogen light source 11, and a data connection line 12. Visible / Near Infrared Spectrometer 13. Wherein, the stage 7 and the object support 8 are fixed through a diameter of 1.0cm drilling; The probe end of 10 is fixed through object holder 8; The incident optical fiber end of described Y-type optical fiber 10 is connected with halogen lamp light source 11, to obtain stable light source input; The reflective optical fiber end of described Y-type optical fiber 10 is connected with visible/ The near-infrared spectrometer is connected to 13 to obtain the reflectance spectrum of the visible/near-infrared region of the color-sensitive material; the visible/near-infrared spectrometer 13 is connected to the computer through the data line 12 to operate the corresponding spectrometer software in real time to obtain the sensor array spectral data.

The present invention will be described in detail below in conjunction with specific implementation cases. However, these implementation cases do not limit the present invention, and any structural, method, or functional changes made by those skilled in the art based on these implementation cases are included in the protection scope of the present invention.

Implementation case 1: Detection of different concentrations of ethanol gas

A novel method for detecting ethanol gas with different concentrations, comprising the steps of:

(1) As shown in Figure 1, it is a 1×2 gas capture sensor array, which is produced as follows: (1) Accurately weigh 10 mg of metalloporphyrin zinc (TPPZn) and tetraphenylporphine manganese chloride (OEPMncl) color-sensitive The material was dissolved in dichloromethane, and the volume was adjusted to a 5mL volumetric flask, and solubilized by ultrasonication for 15min to obtain a solution with a concentration of 2mg/mL. (2) Use a 100×0.3mm capillary to absorb 1uL of the color-sensitive material solution and use the array template to assist spotting on a 3×3cm hydrophobic reversed silica gel plate. (3) After the color-sensitive material is volatilized on the silica gel plate until it is stable, a 1×2 gas capture sensor array as shown in Figure 1 is obtained, which is individually sealed and stored in a sample bag for later use.

(2) Take ethanol solutions of different concentrations (volume concentrations) in beakers, and the corresponding concentration gradients are successively 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, each Each concentration gradient corresponds to four parallel test samples. After the samples to be tested are placed in the gas collection chamber for 20 minutes, they are in contact with the gas capture sensor array for 5 minutes under the carrier gas. Take out the reacted color-sensitive sensor array, place it on the object stage in the dark box operation room, and adjust the height of the object support so that the optical fiber probe covers the circular spot of the color-sensitive material. The corresponding parameters of the spectrometer are set as follows: integration time 20ms, smoothness 5 points, average scan times 5 times, after corresponding dark correction and white correction, visible/near-infrared spectral data detection is performed.

(3) The collected visible/near-infrared spectrum contains noise information, background drift, etc., and the standard normal variable transformation (SNV) is used to preprocess the spectral data; the joint interval partial least square method (si-PLS) is used to filter variables, And model the spectral data to quantitatively analyze the content of ethanol gas components in the sample. Figure 3 shows the si-PLS detection model of TPP-Zn to ethanol. When the principal component is 4, combined with the [2 3 18 25] interval, the correlation coefficient reaches 0.9706, and the RMSECV is 0.0622. The stability of the model is good.

Implementation case 2: Detection of ethanol gas in the mixed gas of ethanol and ethyl acetate

A novel ethanol, ethyl acetate mixed gas, ethanol gas detection method, comprising the following steps:

(1) Same as (1) in Implementation Case 1: Detection of ethanol gas with different concentrations.

(2) Take ethanol and ethyl acetate solutions of the same concentration in a beaker, and the mixing volume ratio is: the volume ratio of ethanol is 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, the proportion of ethyl acetate volume is 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, each mixing ratio corresponds to three parallel To test the samples, place the samples to be tested in sequence in the gas collection chamber for 20 minutes, and then contact the gas capture sensor array for 5 minutes under the carrier gas. Visible/near-infrared spectrometer detection is the same as the spectral detection in (2) in Implementation Case 1: Detection of ethanol gas with different concentrations.

(3) The collected visible/near-infrared spectrum contains noise information, background drift, etc., and the standard normal variable transformation (SNV) is used to preprocess the spectral data; the joint interval partial least square method (si-PLS) is used to filter variables, And model the spectral data to quantitatively analyze the content of ethanol gas in the sample. Figure 4 shows the si-PLS detection model of TPP-Zn for ethanol and ethyl acetate mixed gas. When the principal component is 5, combined with the [5 11 15 21] interval, the correlation coefficient reaches 0.9672, and the RMSECV is 0.067, the model stability is good.

In the description of this specification, references to the terms "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific examples," or "some examples" are intended to mean that the implementation A specific feature, structure, material, or characteristic described by an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the invention is defined by the claims and their equivalents.

Claims (5)

1. A method for detecting volatile organic compounds, characterized in that, comprising the following steps: Step 1, the production of gas capture sensors: After quantum chemical test calculations, spectral dynamic analysis, and combined with physical and chemical analysis experiments, the metalloporphyrin zinc TPPZn sensitive to ethanol and the tetraphenylporphine sensitive to ethyl acetate were screened out. Manganese chloride OEPMncl; two color-sensitive materials are dissolved in an organic solvent at a certain concentration, and a C2 reverse-phase silica gel plate is used as a color-sensitive material carrier; the color-sensitive material is fixed on the sensor carrier by capillary spotting method to form a 1 ×2 gas capture sensor array (4); Step 2, capture diffuse reflectance spectrum detection in the visible/near-infrared band region of the sensor: After the volatile organic compounds are effectively enriched in the gas collection chamber (2), they are carried into the reaction chamber (5) by the carrier gas, and placed in the reaction chamber (5) The gas capture sensor (4) at the top responds fully; the tungsten-halogen light source (11) is connected to the visible/near-infrared spectrometer (13) with a Y-shaped optical fiber (10); the tungsten-halogen light source (11) is used as an input A light source, scanning the sensor after capturing the gas; using a visible/near-infrared spectrometer (13) to obtain the diffuse reflectance spectrum of the visible/near-infrared band region of the sensor after capturing the gas; Step 3, the optimization analysis of the organic gas detection model: the standard normal variable transformation SNV is used to preprocess the visible/near-infrared spectral data, and the joint interval partial least square method si-PLS is used for modeling optimization analysis; In the production of gas capture sensors in step 1, the porphyrins of various metal centers, push-pull electrons and substituent groups are calculated by quantum chemistry, combined with ultraviolet spectral dynamic analysis, and finally combined with experimental verification, the metal porphyrins sensitive to alcohol gases are selected Phenylzinc TPPZn and Tetraphenylporphine Manganese Chloride OEPMncl sensitive to ester gases as a color-sensitive sensor-gas capture sensor for visible/near-infrared spectroscopy devices; In step 3, the detection model of the organic gas is the detection model of ethanol and the detection model of ethyl acetate; ], [1002.76nm 1025.7nm] in four wavelength intervals; the detection model of ethyl acetate, in the joint [371.15nm401.68nm], [666.64nm 694.15nm], [749.21nm 775.76nm], [802.64nm 828.55nm] nm] within four wavelength intervals. 2. a kind of method for detecting volatile organic compounds according to claim 1, is characterized in that, the color-sensitive material in step 1, metalloporphyrin zinc TPPZn, tetraphenylporphine manganese chloride OEPMncl are dissolved in two Chloromethane solvent, a solution with a dilution concentration of 2.0mg/mL; porphyrin compounds are printed and dyed on a C2 reverse silica gel plate; in the capillary spotting method, two color-sensitive materials form a diameter of about 0.2cm on the silica gel plate round spot. 3. A method for detecting volatile organic compounds according to claim 1, characterized in that, in step 2, the effective enrichment is that the amount of organic compound is 8.0mL, and the gas collection time is 20min; The reaction is carried by the carrier gas into the reaction chamber (5) to completely contact with the sensor and react for 5 minutes. 4. A method for detecting volatile organic compounds according to claim 1, characterized in that in step 2, the tungsten halogen light source is a multi-purpose light source with a lifespan of up to 10,000 hours, suitable for visible/near The infrared wavelength range is 360nm-2000nm; the stability between the output peaks of the tungsten-halogen lamp is 0.15%, and the drift is less than 0.3% per hour. 5. A method for detecting volatile organic compounds according to claim 1, characterized in that, in step 2, the visible/near-infrared spectrometer (13) has a wavelength range of 300nm to 1100nm, covering visible and near-infrared regions ; The spectrometer grating is 600 reticles/mm, and the optical resolution is 1.5nm FWHM.