Gas detection system and method for pepper infected fungal disease spores

Abstract

The invention discloses a gas detection system and method for pepper infected fungal disease spores in the technical field of crop disease detection.The gas detection system comprises a collection module, a separation module, an enrichment module and a detection module.The collection module is used for sucking in external air according to the air pressure difference air inlet principle; the separation module is used for receiving the gas sucked by the acquisition module, is provided with a coarse filter, is used for carrying out primary purification and converging the gas into a micro-fluidic chip, is provided with an analog-to-digital converter, is used for carrying out analog-to-digital conversion on an input signal, and is used for carrying out secondary purification to obtain gas to be detected by utilizing PCA (Principal Component Analysis); and the enrichment module is provided with a gas transition cabin and is used for receiving the to-be-detected gas treated by the separation module, and a gas heater is utilized. According to the invention, precise detection of pepper fungal disease gas can be realized, and the method is good in timeliness, high in precision, low in cost and good in reliability.

Description

Technical Field

[0001] The invention relates to the technical field of crop disease detection, and in particular to a gas detection system and method for pepper infected with fungal disease spores. Background Art

[0002] In recent years, pepper has become one of the most important cultivated crops in Jiangsu Province. Since 2009, its planting area and processing scale have reached the first place in China. Due to the increase in varieties, the occurrence of diseases has become increasingly serious. Many typical pepper diseases are caused by fungal infections. For example, eight pathogenic fungi such as Aspergillus terreus, Aspergillus niger, Aspergillus kawachii, Aspergillus fumigatus, and Aspergillus flavus are easy to infect peppers. Therefore, the early prediction and detection of pepper fungal infection symptoms are imminent for its production and yield increase.

[0003] In terms of detection methods, the current detection technology methods are: combustible gas detectors, gas leak detectors, and electrochemical gas sensors. The combustible gas detector method is affected by environmental factors: environmental factors such as temperature and humidity may affect the detection accuracy. High maintenance requirements: regular calibration and maintenance are required, and the cost of use is high; gas leak detectors may have insufficient sensitivity for some low-concentration target compounds; electrochemical gas sensors, such sensors usually have a limited service life and need to be replaced regularly, and may be interfered by other gases or environmental factors.

[0004] Recently, the detection of pepper fungal spore gas has attracted widespread attention. Farmland environment detection is an important issue in establishing a crop safety line of defense. It is a general trend to collect samples to be tested in the environment for gas detection. In addition to detecting whether there are pepper fungal spores in the environment, it also plays a role in prevention and protection, that is, protecting the growth safety of peppers through the detection of disease fungal spore gas, making farmland protection more scientific and effective.

[0005] The above-mentioned existing gas detection of fungal spores infected with pepper diseases has at least the following defects: (1) Some detection methods may not be sensitive enough to low concentrations of spores, and therefore may miss mild or early infections. This may lead to failure to timely detect and control fungal spore diseases, thereby affecting pepper yield and quality; (2) Some traditional spore detection methods may require a long time for sample processing and analysis and cannot provide instant results. This may be a shortcoming in some scenarios that require quick decision-making; (3) Some advanced gas detection methods, such as combustible gas detectors, may require expensive equipment and professional technicians to operate and maintain, which may limit their application in some laboratories or field environments. Summary of the invention

[0006] One of the purposes of the present invention is to provide a gas detection system for pepper infected with disease spores, aiming to solve the technical problems of existing farmland disease gas detection methods and scales being single and having poor timeliness.

[0007] The object of the present invention is achieved by adopting the following technical scheme: a gas detection system for pepper infected with fungal disease spores, comprising a collection module, a separation module, an enrichment module and a detection module connected in sequence, wherein the collection module comprises an air suction pump, the air suction pump is connected to the inlet of a gas cabin through a collection pipe, and an exhaust valve 1 is arranged on the gas cabin; the gas in the gas cabin is discharged by the exhaust valve 1, so that a pressure difference is generated in the gas cabin, and the external gas is sucked in in combination with the air suction pump;

[0008] The separation module includes a coarse filter, the coarse filter of the separation module receives the gas discharged from the gas cabin outlet of the collection module, the coarse filter is connected to the serpentine microchannel tube via a primary purification tube, a gas flow sensor is arranged in the serpentine microchannel tube, the gas flow sensor is connected to the microfluidic chip via an analog-to-digital converter, and an exhaust valve 2 is arranged on the tube wall of the serpentine microchannel tube;

[0009] The enrichment module comprises a gas transition chamber, the gas transition chamber inlet of the enrichment module receives the gas discharged from the serpentine microchannel tube outlet of the separation module, and a gas heater is arranged inside the gas transition chamber;

[0010] The detection module comprises a low-temperature plasma instrument, and the low-temperature plasma instrument of the detection module receives the gas exhausted from the outlet of the gas transition chamber of the enrichment module.

[0011] As a further improvement of the present invention, the gas cabin of the collection module is connected to the coarse filter of the separation module via a collecting pipe, the serpentine microchannel tube of the separation module is connected to the gas transition chamber of the enrichment module via a secondary purification tube, and the gas transition chamber of the enrichment module is connected to the low-temperature plasma instrument of the detection module via a target gas inlet pipe.

[0012] As a further improvement of the present invention, the coarse filter is cylindrical, and an inlet and an outlet are respectively arranged at the front and rear ends of the cylindrical coarse filter, and activated carbon is arranged inside the cylindrical coarse filter.

[0013] As a further improvement of the present invention, the gas heater is a resistance heater.

[0014] As a further improvement of the present invention, flow control valves are provided on the collecting pipe, primary purification pipe, secondary purification pipe and target gas inlet pipe, and separation filter materials are provided in the collecting pipe, primary purification pipe, secondary purification pipe and target gas inlet pipe, and the separation filter materials are activated carbon.

[0015] As a further improvement of the present invention, the collecting pipe and the secondary purification pipe are both made of transparent materials, the gas cabin, the serpentine microchannel tube and the gas transition chamber are also made of transparent materials, an ultraviolet lamp is arranged corresponding to the top of the gas cabin and the collecting pipe, and an ultraviolet lamp is arranged corresponding to the top of the serpentine microchannel tube, the secondary purification tube and the gas transition chamber.

[0016] As a further improvement of the present invention, the length of the serpentine microchannel tube is 0.95-1.05m, the inner diameter of the serpentine microchannel tube is 9.8-10.2cm, the serpentine microchannel tube includes a plurality of parallel straight segments, an arc-shaped connecting segment is provided between the ends of two adjacent straight segments on the left and right, any two adjacent connecting segments are staggered front and back, and the gas flow sensor is arranged at a position 5-8cm away from the outlet inside the serpentine microchannel tube. The gas movement speed near the outlet of the serpentine microchannel tube is relatively stable.

[0017] The second purpose of the present invention is to provide a detection method for a gas detection system for pepper infected with disease spores, which can achieve faster gas separation and save the time and energy of detectors during the detection process. Its wide application scenarios and huge market scale also bring objective market prospects for the product.

[0018] The object of the present invention is achieved by adopting the following technical scheme: a method for detecting pepper infected with fungal disease spores by a gas detection system, comprising the following steps:

[0019] S1: Use the exhaust valve 1 to discharge the gas in the gas chamber, so that a pressure difference is generated inside and outside the gas chamber, and external gas is sucked in;

[0020] S2: The coarse filter of the separation module receives the gas inhaled by the collection module, and the coarse filter purifies the gas once, and then merges the gas into the serpentine microchannel tube. The gas flow sensor in the serpentine microchannel tube collects the instantaneous flow and cumulative flow of the gas and converts them into a voltage signal, which is transmitted to the analog-to-digital converter. The analog-to-digital converter performs analog-to-digital conversion on the input signal, and converts the voltage signal into a digital signal and transmits it to the microfluidic chip. The microfluidic chip uses the PCA algorithm to analyze the pepper spore fungus. After the analysis and detection of non-pepper fungal disease spore gas, the second exhaust valve is opened to discharge other gases other than pepper fungal disease spores, and secondary purification is performed to obtain pepper fungal disease spore gas;

[0021] S3: The gas transition chamber of the enrichment module receives the pepper fungal disease spore gas processed by the separation module. The gas heater in the gas transition chamber increases the gas temperature, increases the movement speed of the gas molecules, and increases the amount of gas enriched in the gas transition chamber; it is used to prolong the residence time of the gas in the gas transition chamber; S4: The low-temperature plasma instrument of the detection module receives the pepper fungal disease spore gas processed by the enrichment module. The pepper fungal disease spore gas is the target gas. The low-temperature plasma instrument is used to excite and ionize the molecules in the target gas to generate characteristic ions, which are used to enhance the detection signal of the target gas and identify the target gas.

[0022] The acquisition module of the gas detection system of the present invention is provided with a gas cabin, the gas cabin is used to collect air, an exhaust valve is provided on the gas cabin, the gas in the gas cabin is extracted, a vacuum state is created, and external gas is sucked in by a vacuum pump. The separation module includes a coarse filter and a microfluidic chip, the coarse filter is provided with activated carbon, the activated carbon is used to adsorb various gaseous organic matter, odor and other impurities, the microfluidic chip is provided with a serpentine channel, the serpentine channel path is long, the fluid undergoes multiple convection and diffusion inside the channel, which helps to increase the mixing efficiency of the fluid, and the mixing efficiency is conducive to improving the filtering effect, an analog-to-digital converter is provided in the microfluidic chip, the input signal is converted into analog-to-digital, and the pepper spore fungus is analyzed by PCA for secondary purification; an exhaust valve is provided on the microfluidic chip, and the exhaust valve is used to extract non-test gas. The enrichment module is provided with a gas transition chamber, the gas transition chamber is used to collect the gas to be tested, and a gas heater is provided on the gas transition chamber, and the gas heater is used to increase the gas temperature, thereby increasing the movement speed of the gas molecules and prolonging the retention time of the gas in the inner cavity. The detection module is provided with low-temperature plasma, and the low-temperature plasma instrument is used to amplify the signal of the gas to be detected.

[0023] The gas detection method of the present invention comprises the following steps S1: using an exhaust valve to suck out the gas in the gas chamber, so as to generate a pressure difference and inhale external complex gas; S2: receiving the gas inhaled by the collection module, setting a coarse filter, performing a primary purification, and collecting the gas into a microfluidic chip, setting an analog-to-digital converter, performing analog-to-digital conversion on the input signal, using PCA to analyze pepper spore fungi, performing secondary purification, obtaining pepper fungal disease spore gas, and exhausting excess gas using an exhaust valve; S3: receiving the pepper fungal disease spore gas processed by the separation module, and setting a gas heater to increase the gas temperature, thereby increasing the movement speed of the gas molecules; and S4: receiving the target gas processed by the enrichment module, using a low-temperature plasma instrument to excite and ionize the target gas to enhance the detection signal of the target gas, thereby realizing the detection of the virus.

[0024] Compared with the prior art, the beneficial effects of the present invention are: the present invention can realize gas detection of fungal spores infected with peppers, and can realize rapid on-site detection, effectively saving the time and energy of detection personnel during the detection process, and solving the problems of low efficiency, high cost and inaccurate precision of existing gas detection of fungal spore diseases infected with peppers. Its wide application scenarios and huge market scale also bring objective market prospects for the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for describing the embodiments or the prior art are briefly introduced below.

[0026] Figure 1 This is a schematic diagram of the system of the present invention.

[0027] Figure 2 This is a simulation diagram of the microfluidic channel fluid of the serpentine microchannel tube.

[0028] Figure 3 It is the flow chart of the PCA algorithm of the present invention.

[0029] Figure 4 It is a flow chart of the present invention.

[0030] Figure 5 It is a schematic diagram of the structure of each module of the present invention.

[0031] Among them, 1 is an air suction pump, 2 is a collection tube, 3 is a gas cabin, 4 is an exhaust valve 1, 5 is a coarse filter, 6 is a primary purification tube, 7 is a serpentine microchannel tube, 8 is an exhaust valve 2, 9 is a gas transition chamber, 10 is a low-temperature plasma instrument, 11 is a collection tube, 12 is a secondary purification tube, 13 is a target gas inlet tube, and 14 is an ultraviolet lamp. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0033] Some implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the features in the following embodiments and experimental examples may be combined with each other.

[0034] See also Figure 1 and 5 A detection system for detecting pepper fungal spore disease gas includes a collection module, a separation module, an enrichment module and a detection module connected in sequence.

[0035] The collection module includes an air pump 1, which is connected to the inlet of a gas cabin 3 via a collection pipe 2, and an exhaust valve 4 is provided on the gas cabin 3;

[0036] The gas in the gas chamber 3 is exhausted by using the exhaust valve 14, so that a pressure difference is generated in the gas chamber 3, and the external gas is sucked in by combining with the suction pump 1;

[0037] The separation module includes a coarse filter 5, which receives the gas discharged from the outlet of the gas cabin 3 of the collection module. The coarse filter 5 is connected to the serpentine microchannel tube 7 via a primary purification tube 6. A gas flow sensor is arranged in the serpentine microchannel tube 7. The gas flow sensor is connected to the microfluidic chip via an analog-to-digital converter. An exhaust valve 8 is arranged on the tube wall of the serpentine microchannel tube 7. The coarse filter 5 is cylindrical, and an inlet and an outlet are respectively arranged at the front and rear ends of the cylindrical coarse filter 5. Activated carbon is arranged inside the cylindrical coarse filter 5.

[0038] The enrichment module comprises a gas transition chamber 9, the inlet of the gas transition chamber 9 of the enrichment module receives the gas discharged from the outlet of the serpentine microchannel tube 7 of the separation module, and a gas heater is arranged inside the gas transition chamber 9; the gas heater is a resistance heater;

[0039] The detection module comprises a low-temperature plasma instrument 10, and the low-temperature plasma instrument 10 of the detection module receives the gas exhausted from the outlet of the gas transition chamber 9 of the enrichment module.

[0040] The gas chamber 3 of the collection module is connected to the coarse filter 5 of the separation module via the collecting pipe 11, the serpentine microchannel tube 7 of the separation module is connected to the gas transition chamber 9 of the enrichment module via the secondary purification pipe 12, and the gas transition chamber 9 of the enrichment module is connected to the low-temperature plasma instrument 10 of the detection module via the target gas inlet pipe 13.

[0041] The collecting pipe 11, the primary purification pipe 6, the secondary purification pipe 12 and the target gas inlet pipe 13 are all provided with flow control valves, and the collecting pipe 11, the primary purification pipe 6, the secondary purification pipe 12 and the target gas inlet pipe 13 are all provided with separation filter materials, and the separation filter materials are activated carbon.

[0042] The collecting tube 11 and the secondary purification tube 12 are both made of transparent materials, and the gas cabin 3, the serpentine microchannel tube 7 and the gas transition chamber 9 are also made of transparent materials. An ultraviolet lamp 14 is arranged above the gas cabin 3 and the collecting tube 11, and an ultraviolet lamp 14 is arranged above the serpentine microchannel tube 7, the secondary purification tube 12 and the gas transition chamber 9.

[0043] The length of the serpentine microchannel tube 7 is 0.95-1.05m, the inner diameter of the serpentine microchannel tube 7 is 9.8-10.2cm, the serpentine microchannel tube 7 includes a plurality of parallel straight segments, an arc-shaped connecting segment is provided between the ends of two adjacent straight segments on the left and right, any two adjacent connecting segments are staggered front and back, and the gas flow sensor is arranged inside the serpentine microchannel tube 7 at a position 5-8cm away from the outlet.

[0044] A method for detecting pepper infected with fungal disease spores by a gas detection system, comprising the following steps:

[0045] S1: exhaust the gas in the gas chamber 3 by using the exhaust valve 4, so that a pressure difference is generated inside and outside the gas chamber 3, and external gas is sucked in;

[0046] S2: The coarse filter 5 of the separation module receives the gas inhaled by the collection module, and the coarse filter 5 purifies the gas once, and then merges the gas into the serpentine microchannel tube 7. The gas flow sensor in the serpentine microchannel tube 7 collects the instantaneous flow and cumulative flow of the gas and converts them into a voltage signal, and the voltage signal is transmitted to the analog-to-digital converter. The analog-to-digital converter performs analog-to-digital conversion on the input signal, and converts the voltage signal into a digital signal and transmits it to the microfluidic chip. The microfluidic chip uses the PCA algorithm to analyze the pepper spore fungus. After the analysis and detection of non-pepper fungal disease spore gas, the exhaust valve 2 8 is opened to discharge other gases other than pepper fungal disease spores, and secondary purification is performed to obtain pepper fungal disease spore gas;

[0047] S3: The gas transition chamber 9 of the enrichment module receives the pepper fungal disease spore gas processed by the separation module, and the gas heater in the gas transition chamber 9 increases the gas temperature, increases the movement speed of the gas molecules, and increases the amount of gas enriched in the gas transition chamber 9, so as to prolong the retention time of the gas in the gas transition chamber 9;

[0048] S4: The low-temperature plasma instrument 10 of the detection module receives the pepper fungal disease spore gas processed by the enrichment module. The pepper fungal disease spore gas is the target gas. The low-temperature plasma instrument 10 is used to excite and ionize the molecules in the target gas to generate characteristic ions to enhance the detection signal of the target gas and identify the target gas.

[0049] In this embodiment, the collection module has an air pump 1 and a gas cabin 3, and the air pump 1 is used to extract the gas to be analyzed. The sampling channel or sample input channel of the gas cabin 3 is opened. The extracted gas is input into the gas cabin 3. The gas cabin 3 is made of a suitable material that can withstand the target chemical properties and pressure, usually stainless steel. An exhaust valve is provided on the gas cabin 3. The exhaust valve type is an electric valve to achieve precise gas control. The material of the exhaust valve should be corrosion-resistant and compatible with the chemical properties of the target.

[0050] In this embodiment, a coarse filter 5 is provided in the separation module for preliminary filtering of large particles and solid particles. The coarse filter 5 can be a mesh filter or a filter screen, and a suitable pore size is selected to adapt to the size of the particles in the gas. The gas preliminarily treated by the coarse filter 5 is introduced into the microfluidic chip. The microfluidic chip integrates a microchannel functional unit and an analog-to-digital converter, performs analog-to-digital conversion on the input signal, uses PCA to analyze pepper spore fungi, and performs secondary purification for secondary filtration. Ensure that the designed filter unit can effectively remove impurities and non-target gases and improve the purity of pepper fungal disease spore gas. In the final stage of the separation module, an exhaust valve is designed to discharge excess gas. The exhaust valve should be able to accurately control the emission rate and amount of the gas to prevent unnecessary losses or pollution of the environment.

[0051] See also Figure 2 The simulation software Consol Multiphysics was used to simulate the steady-state flow in a 1-meter-long, 0.1-meter-diameter microfluidic channel, with the fluid properties set to a density of 1.225 kg / m 3 、Viscosity 1.7894×10 -5 Pa, temperature is 20℃. The physical boundary conditions are set as the inlet and outlet pressure difference ΔP≈96000Pa, and the flow rate size Q=1μL / min. The geometric dimensions are channel length l=1m, inner diameter d=0.1m. In order to ensure the accuracy of the simulation, the time step is selected as Δt=0.001s, the initial number of iterations is set to 1000, and it is adjusted according to the residual convergence criterion. The simulation method adopts a steady-state model, which is suitable for situations where the flow field remains unchanged for a long time. The color coding represents the change of physical quantities such as velocity or pressure. The red area represents the high-speed flow part, while the green area represents the relatively low-speed area. Turbulence often occurs at corners (red part), because when the fluid encounters an obstacle, a vortex effect is generated, resulting in uneven velocity distribution. The middle yellow part may represent a state of steady flow, that is, there is no obvious shear stress acting near the wall. The whole figure shows how the fluid flows along a curved path and produces different dynamic responses as the shape changes.

[0052] In this embodiment, first, for a given data set X∈Rm×n, where m is the number of samples and n is the number of features, we need to standardize each feature. The specific steps are as follows:

[0053] 1. Calculate the mean u and standard deviation σ of each feature:

[0054] u j is the average value (mean) of the jth feature (or variable), X ij is the observed value of the i-th sample.

[0055] The standardized data is:

[0056] Where Z∈Rm×n is the standardized data matrix.

[0057] 2. Next, calculate the covariance matrix C of the standardized data Z:

[0058] Here, ZT is the transpose of Z.

[0059] If the amount of data is large, the correlation matrix R can be calculated, but after standardization, C and R are actually the same because standardization has eliminated the dimensionality of each feature.

[0060] 3. Perform eigenvalue decomposition on the covariance matrix C:

[0061] Cv i =λ i v i , where λ i is the eigenvalue, v i is the corresponding eigenvector.

[0062] The eigenvalue represents the degree of variation explained by each principal component, while the eigenvector represents the direction of the principal component. The eigenvalues ​​are sorted from large to small, and the first k largest eigenvalues ​​and their corresponding eigenvectors are selected.

[0063] 4. The first k selected eigenvectors are combined into a matrix VK:

[0064] VK=[v1,v2,…,vk], where each column is a feature vector.

[0065] 5. Finally, the original data X is projected into the subspace composed of the selected principal components to obtain the new data representation Y:

[0066] Y=XVK, where Y∈Rm×n is the data representation after dimensionality reduction.

[0067] Through the above steps, we can reduce the dimension of high-dimensional data X to Y while retaining the main information of the data as much as possible. The core of PCA is to find the main variation directions of the data and project along these directions to achieve data dimensionality reduction and feature extraction.

[0068] See also Figure 3, the specific process of PCA is: data preparation-data standardization-covariance matrix construction-eigenvalue and eigenvector calculation-principal component analysis-data projection; data preparation: collect and organize data sets, and may need to perform preprocessing operations such as missing value processing and outlier removal. Data standardization: standardize the data so that each feature has the same scale. Construction of the covariance matrix: If the data dimension is high, you can also choose to calculate the correlation matrix. Calculation of eigenvalues ​​and eigenvectors: solve the eigenvalues ​​and corresponding eigenvectors based on the covariance matrix or correlation matrix. Principal component analysis: select the eigenvectors corresponding to the first k largest eigenvalues ​​as the principal components. Data projection: project the original data into the subspace composed of the selected principal components to achieve dimensionality reduction.

[0069] In this embodiment, a gas transition chamber with a suitable volume is provided in the enrichment module to collect the pepper fungal disease spore gas transmitted from the separation module. The material selection and sealing performance of the gas transition chamber are ensured to prevent gas leakage and external contamination.

[0070] A gas heater is designed inside the gas transition chamber to increase the gas temperature, thereby increasing the movement speed of gas molecules and prolonging the residence time of the gas in the transition chamber. The heater can use electric heating wires or other heating elements to adjust the gas residence time by controlling the temperature of the heater. The pepper fungal disease spore microfluidic separation and enrichment system can achieve a fungal disease spore separation rate of more than 90% and an enrichment rate of more than 95%.

[0071] In this embodiment, the materials, equipment and methods used are:

[0072] 1. Sample Preparation

[0073] Air samples were collected from a fungus-infected pepper field using a spore trap.

[0074] The collected samples are concentrated by filtration or centrifugation to prepare spore suspensions of different concentrations.

[0075] 2. Low temperature plasma treatment

[0076] Spore suspensions of different concentrations were introduced into the low-temperature plasma apparatus 10 respectively.

[0077] Set up the parameters of the plasma instrument:

[0078] Voltage: 500V

[0079] Current: 0.5A

[0080] Gas flow rate: 150sccm

[0081] Processing time: 30 seconds

[0082] Power: 50W

[0083] Operating frequency: 13.56MHz

[0084] The processed samples were immediately transferred to a mass spectrometer for detection.

[0085] 3. Mass spectrometry detection

[0086] The treated samples are detected using a mass spectrometer and the generated ion signals are recorded.

[0087] Set up the mass spectrometer parameters:

[0088] Ion source: APCI

[0089] Scan mode: Full scan

[0090] Scan range: m / z50-500

[0091] Injection method: direct injection

[0092] Resolution: Unit resolution

[0093] The ion signals are analyzed by software to determine the presence and concentration of the target compound.

[0094] 4. Data Analysis

[0095] The mass spectrometer was calibrated using standard solutions to ensure the accuracy of the test results.

[0096] The limit of detection (LOD) and limit of quantification (LOQ) were calculated to evaluate the detection sensitivity.

[0097] The calculation of LOD (limit of detection) and LOQ (limit of quantification) is usually based on the standard curve and the signal-to-noise ratio. Here is how they are calculated:

[0098] 1. Limit of Detection (LOD)

[0099]

[0100] σ: standard deviation of blank samples or low-concentration samples. M is the slope of the calibration curve, which indicates the change in signal response caused by a unit concentration change.

[0101] The calculation steps of σ are as follows:

[0102] Collecting sample data

[0103] Calculate the average

[0104]

[0105] N: sample size.N : The concentration of the Nth sample.

[0106] Calculate the deviation of each data point from the mean

[0107] d i =y i -μ

[0108] Calculate the square of the deviation

[0109]

[0110] Calculating variance

[0111] Calculate the average of all deviation equations (for sample data, use N-1 as the denominator)

[0112]

[0113] Calculating the standard deviation

[0114]

[0115] M: slope of the standard curve.

[0116] The calculation steps of M are as follows:

[0117]

[0118] x N Equal to the value of N, indicating the sample number value of the Nth sample.

[0119] 2. Limit of Quantitation (LOQ)

[0120] LOQ is the lowest concentration of analyte that can be accurately quantified. The commonly used formula is:

[0121]

[0122] Evaluating detection accuracy

[0123] Compare the measured value to the true value and evaluate it using the accuracy formula:

[0124]

[0125] Compare the test results of spore suspensions with different concentrations before and after low-temperature plasma treatment.

[0126]

[0127]

[0128] d1=3×10 4 -1×10 4=2×10 4

[0129] d2=3×10 4 -2×10 4 =1×10 4

[0130] d3=3×10 4 -3×10 4 =0

[0131] d4=3×10 4 -4×10 4 =-1×10 4

[0132] d5=3×10 4 -5×10 4 =-2×10 4

[0133]

[0134]

[0135] In this embodiment, the gas sample collected by the enrichment module is introduced into the low-temperature plasma instrument 10. The molecules in the target gas are excited and ionized by the low-temperature plasma instrument 10 to generate characteristic ions. The detection signal of the target compound is enhanced by excitation and ionization, and the ion signal is detected and recorded. The result is analyzed and processed to achieve a detection sensitivity of 1.581 to 5.27 CFU / ml for pepper fungal disease spores, which is far lower than 10,000 CFU / ml relative to the sample concentration of 1.581 CFU / ml and 5.27 CFU / ml, which means that the detected concentration is very low and the sensitivity is high. The accuracy of the test result is more than 97%, that is, within different concentration ranges, the deviation between the test result and the actual concentration is less than 3%.

[0136] Through low-temperature plasma technology treatment, the detection sensitivity and accuracy of pepper fungal disease spores can be significantly improved.

[0137] This method has high practical value in actual applications and can be used for early warning and disease prevention and control.

[0138] Precautions

[0139] Safe operation: When operating the low-temperature plasma instrument 10 and the mass spectrometer, be sure to follow laboratory safety regulations and wear necessary protective equipment.

[0140] Sample processing: All sample collection, processing and analysis should be carried out under sterile conditions to avoid external contamination.

[0141] Data recording: Record each operation step and test results in detail to ensure the repeatability of the experiment and the reliability of the results.

[0142] In this embodiment, a gas guide pipe is provided to ensure that the gas can flow accurately and controllably in the system. The selected material is stainless steel, which has excellent corrosion resistance and can resist corrosion from most gases. A valve is provided on the gas guide conduit to adjust the flow rate and pressure of the gas. A layer of activated carbon is coated inside the pipe to remove impurities and odors in the air.

[0143] See also Figure 4 The process of the present invention is specifically: air collection-separation-enrichment-detection, to detect whether spore bacteria exist in the air (air sample to be tested in the environment). The specific process is: the collection module uses an air cabin to store gas, uses an exhaust valve to generate a pressure difference, sucks the air from the external environment into the air cabin, completes the work of the collection module, and then merges the gas of the collection module into the separation module. The separation module uses a coarse filter 5 and an analog-to-digital converter set in the microfluidic chip to perform analog-to-digital conversion on the input signal, uses PCA to analyze pepper spore bacteria, and performs secondary purification. At the same time, the microfluidic chip can be properly heated outside. The microfluidic chip has the best separation effect at about 60 degrees. The gas processed by the separation module is merged into the enrichment module. Since the content of the collected gas is small, a gas heater needs to be set on the enrichment module to increase the reaction rate, and then enters the detection module, and the gas to be tested is merged into the low-temperature plasma instrument 10. The molecules in the target gas are excited and ionized by the low-temperature plasma instrument 10 to generate characteristic ions, and the detection signal of the target compound is enhanced by excitation and ionization.

[0144] At the same time, an ultraviolet lamp 14 is arranged in each module, and the ultraviolet lamp 14 is used to inactivate and disinfect the residual gas.

[0145] Based on the above embodiments, the present invention has the following technical effects:

[0146] 1. Efficient separation technology: The system uses microfluidic chip technology, which has a built-in serpentine channel that can promote multiple convection and diffusion of the fluid inside the channel, thereby increasing the mixing efficiency of the fluid and improving the filtration effect. In addition, an analog-to-digital converter is set inside the chip to process the input signal through principal component analysis (PCA) technology, achieving secondary purification of pepper fungal spores and improving the accuracy and sensitivity of detection.

[0147] 2. Gas heating enrichment: A gas heater is designed in the enrichment module, which can increase the movement speed of gas molecules by raising the gas temperature, prolong the residence time of the gas in the transition chamber, and thus improve the enrichment efficiency of the target gas. This design helps to detect low concentrations of fungal spores and improves the sensitivity of detection.

[0148] 3. Low-temperature plasma enhanced detection: The detection module uses low-temperature plasma technology to excite and ionize the molecules in the target gas to generate characteristic ions. By excitation and ionization, the detection signal of the target compound is enhanced, making the detection more sensitive and accurate. This method can significantly improve the detection sensitivity and achieve effective detection of low-concentration fungal spores.

[0149] 4. On-site rapid detection capability: The system realizes on-site rapid detection, effectively saving the time and energy of the detection personnel. By optimizing the design and operation process of each module, the system can complete the whole process from gas collection to detection in a short time, which is particularly suitable for scenarios that require rapid decision-making.

[0150] 5. High accuracy and sensitivity: After experimental verification, the detection accuracy of the system reached more than 97%, and the detection sensitivity reached 1.581-5.27 CFU / ml, which is much lower than the detection limit of traditional methods. This shows that the system has high detection performance and can provide reliable detection results in different concentration ranges.

[0151] 6. Wide applicability and market prospects: The system is not only suitable for laboratory environments, but can also be used for field testing, and has a wide range of application scenarios. Due to the continuous expansion of pepper planting area and processing scale, the system has huge market potential and can provide strong support for agricultural production.

[0152] 7. Safety and reliability: The system design takes into account the safe operation and sterile conditions of sample handling, ensuring the repeatability of the experiment and the reliability of the results. At the same time, the ultraviolet lamp 14 installed in each module can inactivate and disinfect the residual gas, ensuring the safety and environmental protection of the system.

[0153] In summary, the present invention proposes a gas detection system and method for fungal disease spores of pepper infection that is efficient, accurate, rapid and has broad application prospects, providing new ideas and technical support for the development of agricultural disease detection technology.

[0154] The above embodiments describe the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, modifications and changes made by those skilled in the art shall be within the scope of protection of the claims attached to the present invention as long as they do not depart from the spirit and scope of the present invention.

Claims

1. A gas detection system for pepper infected with fungal disease spores, characterized in that: It includes a collection module, a separation module, an enrichment module and a detection module which are connected in sequence. The collection module includes an air suction pump, which is connected to the gas cabin inlet via a collection pipe, and an exhaust valve 1 is provided on the gas cabin; The separation module includes a coarse filter, the coarse filter of the separation module receives the gas discharged from the gas cabin outlet of the collection module, the coarse filter is connected to the serpentine microchannel tube via a primary purification tube, a gas flow sensor is arranged in the serpentine microchannel tube, the gas flow sensor is connected to the microfluidic chip via an analog-to-digital converter, and an exhaust valve 2 is arranged on the tube wall of the serpentine microchannel tube; The enrichment module comprises a gas transition chamber, the gas transition chamber inlet of the enrichment module receives the gas discharged from the serpentine microchannel tube outlet of the separation module, and a gas heater is arranged inside the gas transition chamber; The detection module comprises a low-temperature plasma instrument, and the low-temperature plasma instrument of the detection module receives the gas exhausted from the outlet of the gas transition chamber of the enrichment module.

2. A gas detection system for pepper infected with fungal disease spores as claimed in claim 1, characterized in that: The gas cabin of the collection module is connected to the coarse filter of the separation module via a collecting pipe, the serpentine microchannel tube of the separation module is connected to the gas transition chamber of the enrichment module via a secondary purification tube, and the gas transition chamber of the enrichment module is connected to the low-temperature plasma instrument of the detection module via a target gas inlet tube.

3. A gas detection system for pepper infected with fungal disease spores as claimed in claim 1 or 2, characterized in that: The coarse filter is in a cylindrical shape, and an inlet and an outlet are respectively arranged at the front and rear ends of the cylindrical coarse filter, and activated carbon is arranged inside the cylindrical coarse filter.

4. A gas detection system for pepper infected with fungal disease spores as claimed in claim 1 or 2, characterized in that: The gas heater is a resistance heater.

5. A gas detection system for pepper infected with fungal disease spores as claimed in claim 2, characterized in that: The collecting pipe, the primary purification pipe, the secondary purification pipe and the target gas inlet pipe are all provided with flow control valves, and the collecting pipe, the primary purification pipe, the secondary purification pipe and the target gas inlet pipe are all provided with separation filter materials, and the separation filter materials are activated carbon.

6. A gas detection system for pepper infected with fungal disease spores as claimed in claim 2, characterized in that: The collecting tube and the secondary purification tube are both made of transparent materials, and the gas cabin, the serpentine microchannel tube and the gas transition chamber are also made of transparent materials. An ultraviolet lamp is arranged above the gas cabin and the collecting tube, and an ultraviolet lamp is arranged above the serpentine microchannel tube, the secondary purification tube and the gas transition chamber.

7. A gas detection system for pepper infected with fungal disease spores as claimed in claim 1 or 2, characterized in that: The length of the serpentine microchannel tube is 0.95-1.05m, the inner diameter of the serpentine microchannel tube is 9.8-10.2cm, the serpentine microchannel tube includes a plurality of parallel straight segments, an arc-shaped connecting segment is provided between the ends of two adjacent straight segments on the left and right, any two adjacent connecting segments are staggered front and back, and the gas flow sensor is arranged inside the serpentine microchannel tube at a position 5-8cm away from the outlet.

8. A method for detecting a gas detection system for detecting spores of fungal diseases in peppers as described in claims 1-7, characterized in that The steps include: S1: Use exhaust valve 1 to discharge the gas in the gas cabin, so that a pressure difference is generated inside and outside the gas cabin, and external gas is sucked in; S2: The coarse filter of the separation module receives the gas inhaled by the collection module, and the coarse filter purifies the gas once, and then merges the gas into the serpentine microchannel tube. The gas flow sensor in the serpentine microchannel tube collects the instantaneous flow and cumulative flow of the gas and converts them into a voltage signal, which is transmitted to the analog-to-digital converter. The analog-to-digital converter performs analog-to-digital conversion on the input signal, and converts the voltage signal into a digital signal and transmits it to the microfluidic chip. The microfluidic chip uses the PCA algorithm to analyze the pepper spore fungus. After the analysis and detection of non-pepper fungal disease spore gas, the second exhaust valve is opened to discharge other gases other than pepper fungal disease spores, and secondary purification is performed to obtain pepper fungal disease spore gas; S3: The gas transition chamber of the enrichment module receives the pepper fungal disease spore gas processed by the separation module, and the gas heater in the gas transition chamber increases the gas temperature, increases the movement speed of the gas molecules, and increases the amount of gas enriched in the gas transition chamber; S4: The low-temperature plasma instrument of the detection module receives the pepper fungal disease spore gas processed by the enrichment module. The pepper fungal disease spore gas is the target gas. The low-temperature plasma instrument is used to excite and ionize the molecules in the target gas to generate characteristic ions to enhance the detection signal of the target gas and identify the target gas.

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