Pesticide residue rapid detection system and method based on enzyme-free sensor

Abstract

The invention belongs to the field of pesticide detection, and particularly relates to a pesticide residue rapid detection system based on an enzyme-free sensor, the pesticide residue rapid detection system comprises a bottom plate, the bottom of the bottom plate is fixedly connected with a plurality of uniformly distributed non-slip mats, the top of the bottom plate is fixedly connected with a solution tank, and the upper end of the bottom plate and the left side of the solution tank are fixedly connected with a bracket; a connecting sleeve is fixedly connected to the lower end of the support, and a connecting rod is slidably connected into the connecting sleeve in a sleeved mode. Through the design of the solution tank, a solution to be detected can be stored, the sliding seat and the connecting sleeve can be relatively connected and fixed through the insertion matching of the clamping ball and the clamping groove, and the sliding seat can be driven to move downwards when the fixed seat is pulled down, so that the insertion matching of the clamping ball and the clamping groove at another position can be realized; at the moment, the height of the sensor is reduced, the sensor probe is in contact with the solution to detect pesticide residues in the solution, and the detection operation is convenient and rapid.

Description

Technical Field

[0001] This project belongs to the field of pesticide detection, and specifically involves a rapid pesticide residue detection system based on enzyme-free sensors. Background Art

[0002] The pesticide residue detection device based on enzyme-free sensors is mainly used for on-site rapid screening and quantitative analysis of pesticide residues on the surface and inside agricultural products such as fruits, vegetables, and grains. It is suitable for scenarios such as farmers' markets, production bases, and quality inspection agencies. It can effectively solve problems such as the easy inactivation of enzyme reagents and the complex detection process of large-scale instruments in traditional detection methods, and realize the rapid detection of various pesticide residues such as organophosphorus and carbamates, providing convenient and reliable technical support for agricultural product safety supervision and quality control, and ensuring the safety of agricultural products from production to circulation.

[0003] In existing technologies, enzyme-free sensors are not easy to use during detection, which affects detection efficiency. Furthermore, they are difficult to disassemble after installation. If the enzyme-free sensor is damaged or malfunctions, disassembly is time-consuming and labor-intensive, and repair and maintenance are cumbersome. Therefore, improvements are needed. Summary of the Invention

[0004] The purpose of this solution is to provide a rapid detection system for pesticide residues based on enzyme-free sensors to solve the problems of inconvenient operation and use and inconvenient disassembly, inspection and maintenance of sensors.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a rapid detection system for pesticide residues based on an enzyme-free sensor, comprising a base plate, the bottom of which is fixedly connected to a plurality of evenly distributed anti-slip pads, the top of which is fixedly connected to a solution tank, the upper end of the base plate and located on the left side of the solution tank is fixedly connected to a bracket, the lower end of the bracket is fixedly connected to a connecting sleeve, the internal sliding sleeve of the connecting sleeve is connected to a connecting rod, the bottom of the connecting rod is fixedly connected to a fixed seat, the internal sliding sleeve of the fixed seat is connected to a sensor, a transmission line is provided on the top of the sensor, a connecting mechanism is provided on the sensor, and a moving mechanism is provided on the connecting sleeve.

[0006] The principle of this solution is as follows: when in use, the sample to be tested is cut into pieces and placed in the extraction chamber, and the extract is added. After ultrasonic vibration, the extract is obtained, and the extract is filtered through the filter membrane and injected into the solution tank. Then, the fixed seat is pulled down, and the fixed seat drives the connecting rod and the slide to move downward. The slide will slide along the connecting sleeve, and the slide will drive the card ball to move. The card ball will roll along the arc surface of the card slot. The card ball will be squeezed and move horizontally. The card ball will drive the support block to move, and the support block will squeeze the second spring, and then the card ball can be separated from the card slot. As the slide moves downward, the card ball can be pushed into the card slot at another position under the elastic action of the second spring. At this time, the relative position of the slide and the connecting sleeve can be fixed, and at the same time, the sensor will move downward and extend into the solution tank. The sensor probe will contact the solution for detection, and the enzyme-free electrode will contact the sample solution. The target pesticide molecules are captured by the molecular imprinting layer, causing the charge distribution on the electrode surface to change, so that the pesticide residue can be detected. The detection operation is convenient and fast.

[0007] When the sensor needs to be disassembled, the sensor is directly rotated. The arc surface of the arc groove inside the sensor will squeeze and push the arc block, and the arc block will slide outward. The arc block will drive the slider and the push rod to move. The slider will slide along the fixed rod and squeeze the first spring to separate the arc block from the arc groove. Then the sensor can be pulled out from the fixing seat, which is convenient for disassembly of the sensor and its inspection and maintenance.

[0008] The technical effect of this solution is that: by designing the solution tank, the solution to be tested can be stored. By plugging the card ball into the card slot, the slide seat and the connecting sleeve can be relatively connected and fixed. When the fixed seat is pulled down, the slide seat can be driven downward to realize the plugging and matching of the card ball with the card slot at another position. At this time, the sensor height will be lowered and the sensor probe can be in contact with the solution to detect pesticide residues in the solution. The detection operation is convenient and fast. By designing the arc block to be plugged into the arc groove inside the sensor housing, the sensor can be limited, and the connection and fixation of the sensor to the fixing seat can be achieved. The arc block and the arc groove can be separated by rotating the sensor, and the sensor can be pulled out from the inside of the fixing seat, which is convenient for disassembly of the sensor and its inspection and maintenance.

[0009] Furthermore, the connection mechanism includes a fixing rod, two symmetrically distributed fixing rods are fixedly connected to the interior of the fixing seat, a first spring is provided on the outside of the fixing rod, a slider is slidably sleeved on the outside of the fixing rod, the slider is slidably connected to the fixing seat, a push rod is fixedly connected to the top of the slider, the push rod is slidably connected to the fixing seat, and an arc block is fixedly connected to the bottom of the slider, the arc block is slidably connected to the fixing seat, and the arc block is slidably connected to the sensor. The design of the connection mechanism facilitates the disassembly of the sensor.

[0010] Furthermore, one end of the first spring is fixedly connected to the slider, and the other end of the first spring is fixedly connected to the fixing seat. By designing the first spring, the force of the first spring can act on the slider.

[0011] Furthermore, an arc-shaped groove is provided inside the sensor, and an arc-shaped block is slidably connected inside the arc-shaped groove. By designing the arc-shaped groove, the arc-shaped block can slide inside the sensor.

[0012] Furthermore, the movement mechanism includes a slot, the connecting sleeve having a slot formed therein, a locking ball movably sleeved therein, a sliding seat movably sleeved outside the locking ball, the sliding seat slidably connected to the connecting sleeve, the sliding seat being fixedly connected to the connecting rod, a support block movably sleeved outside the locking ball, the support block slidably connected to the sliding seat, and a second spring disposed inside the sliding seat. The design of the movement mechanism facilitates the movement of the sensor.

[0013] Furthermore, the number of the clamping slots is multiple, and the multiple clamping slots are evenly distributed inside the connecting sleeve. By designing multiple clamping slots, the clamping ball can roll into the clamping slots at different positions.

[0014] Furthermore, one end of the second spring is fixedly connected to one of the support blocks, and the other end of the second spring is fixedly connected to the other support block. By designing the second spring, the force of the second spring can act on the support block.

[0015] Furthermore, the sensor comprises an electrode substrate, a molecular imprinting layer and a conductive probe connected in sequence, wherein the electrode substrate is a disc-shaped structure with a diameter of 3-5 mm, the edge of which is in an arc transition and the surface is polished; The molecularly imprinted layer is a circular film covering the upper surface of the electrode substrate with a thickness of 50-200 nm. The surface of the film is distributed with porous recognition channels with a diameter of 10-50 nm. The inner wall of the channel is modified with functional groups complementary to the target pesticide molecules. The molecularly imprinted layer is prepared by an electropolymerization method: using the target pesticide molecule as a template, 0.1-0.5 mol / L functional monomer, 0.05-0.2 mol / L cross-linking agent, and the template molecule are dissolved in a 0.1 mol / L phosphate buffer at a molar ratio of 2:1. A constant voltage of 0.8-1.2 V is applied to the electrode substrate for electropolymerization for 15-25 minutes. After the polymerization is completed, the template molecule is eluted with a methanol-acetic acid mixed solution with a volume ratio of 9:1 to form a specific recognition structure; The conductive probe is a copper probe with a diameter of 0.5-1 mm. Its lower end is vertically embedded in the center of the electrode substrate and contacts the bottom of the molecular imprinted layer. The upper end passes through the insulating shell of the sensor and is welded to the core wire of the transmission line.

[0016] Furthermore, the end of the transmission line away from the sensor is connected to a control module, the control module includes a signal acquisition unit, a data processing unit, an interference elimination unit and an environmental compensation unit, and the environmental compensation unit has a built-in temperature and humidity sensor; The signal acquisition unit receives the electrical signal output by the sensor through the transmission line, converts it into a digital signal through a 24-bit A / D converter, and performs time integration processing according to formula (1) to obtain the integrated signal value U:

[0017] in, is the instantaneous voltage signal at time t, is the detection start time, The end time of the test, is the signal attenuation coefficient; The data processing unit substitutes the integrated signal value U into the concentration-response model to obtain the initial concentration value C0:

[0018] Wherein, a, b, and c are calibration coefficients obtained by experimental fitting of standard solutions; The interference elimination unit sets the interval between two detections as Δt. If Δt < 10 min, the residual interference correction is enabled. If 10 min ≤ Δt < 30 min, the time attenuation factor f(t) is calculated according to formula (3):

[0019] If Δt ≥ 30 min, the residual interference is considered negligible and C0 is directly used as the intermediate value; Then, the final concentration value C before the last test is obtained, and the difference between the initial concentration value C0 and C before is calculated as ΔC = C0 - C before. If ΔC > 2 × C before or ΔC > 0.2 mg / kg, an abnormal fluctuation warning is triggered, and the difference correction coefficient k difference is introduced according to formula (4):

[0020] The environmental compensation unit obtains the detection environment humidity H and calculates the humidity influence coefficient kwet according to formula (5):

[0021] 50%RH is the standard humidity. When H>50, kwet=1. The detection concentration C finally output by the control module is calculated according to formula (6):

[0022] in, The last detection end time. The start time of this test. is the humidity integral value during the interval; The control module outputs a pulsed operating voltage to the sensor through the transmission line, and outputs a 1.8V reverse cleaning voltage after each test. At the same time, it records the baseline voltage Vbase after cleaning. If Vbase - Vmark is greater than 8mV for three consecutive tests, and Vmark is the factory calibration baseline, a sensor maintenance prompt is triggered. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A three-dimensional diagram of the overall structure of an embodiment of the present invention; Figure 2 For the embodiment of the present invention Figure 1 A three-dimensional cross-sectional view of the local structure; Figure 3 For the embodiment of the present invention Figure 2 A magnified view of point A; Figure 4 For the embodiment of the present invention Figure 2 A front sectional view of the connecting sleeve; Figure 5 4 is a logic block diagram of a control module in an embodiment of the present invention.

[0024] The following is a further detailed description through specific implementation methods: The figure marks in the drawings of the specification include: 1. base plate; 2. anti-slip pad; 3. solution tank; 4. bracket; 5. connecting sleeve; 6. connecting rod; 7. fixing seat; 8. connecting mechanism; 9. moving mechanism; 10. sensor; 11. transmission line; 81. fixing rod; 82. first spring; 83. slider; 84. push rod; 85. arc block; 86. arc groove; 91. card slot; 92. card ball; 93. slide seat; 94. support block; 95. second spring. DETAILED DESCRIPTION

[0025] The embodiment is basically as shown in the attached Figure 1-4 As shown: A rapid detection system for pesticide residues based on enzyme-free sensors includes a base plate 1, the bottom of the base plate 1 is fixedly connected to a plurality of evenly distributed anti-slip pads 2, the top of the base plate 1 is fixedly connected to a solution tank 3, the upper end of the base plate 1 and the left side of the solution tank 3 is fixedly connected to a bracket 4, the lower end of the bracket 4 is fixedly connected to a connecting sleeve 5, the inner sliding sleeve of the connecting sleeve 5 is connected to a connecting rod 6, the bottom of the connecting rod 6 is fixedly connected to a fixing seat 7, the inner sliding sleeve of the fixing seat 7 is connected to a sensor 10, a transmission line 11 is provided on the top of the sensor 10, a connecting mechanism 8 is provided on the sensor 10, and a moving mechanism 9 is provided on the connecting sleeve 5.

[0026] The first spring 82 is designed so that the force of the first spring 82 can act on the slider 83. The outer side of the fixed rod 81 is slidably sleeved with the slider 83. The slider 83 is slidably connected to the fixed seat 7. The top of the slider 83 is fixedly connected with a push rod 84. The push rod 84 is slidably connected to the fixed seat 7. The bottom of the slider 83 is fixedly connected with an arc block 85. The arc block 85 is slidably connected to the fixed seat 7. The arc block 85 is slidably connected to the sensor 10. The interior of the sensor 10 is provided with an arc groove 86. The arc block 85 is slidably connected to the interior of the arc groove 86. By designing the arc groove 86, the arc block 85 can slide inside the sensor 10. By designing the connecting mechanism 8, the sensor 10 is convenient to disassemble.

[0027] Among them, the moving mechanism 9 includes a slot 91, a slot 91 is opened inside the connecting sleeve 5, and a card ball 92 is movably sleeved inside the slot 91. There are multiple slots 91, and multiple slots 91 are evenly distributed inside the connecting sleeve 5. By designing multiple slots 91, the card ball 92 can roll into the slots 91 at different positions. The outer side of the card ball 92 is movably sleeved with a slide 93, and the slide 93 is slidably connected to the connecting sleeve 5. The slide 93 is fixedly connected to the connecting rod 6. The outer side of the card ball 92 is movably sleeved with a support block 94, and the support block 94 is slidably connected to the slide 93. A second spring 95 is provided inside the slide 93, and one end of the second spring 95 is fixedly connected to one of the support blocks 94, and the other end of the second spring 95 is fixedly connected to the other support block 94. By designing the second spring 95, the force of the second spring 95 can act on the support block 94. By designing the moving mechanism 9, it is convenient to push the sensor 10 to move.

[0028] The principle of this solution is that when in use, the sample to be tested is cut into pieces and placed in the extraction chamber, and the extracting liquid is added. The extracting liquid is obtained after ultrasonic vibration. The extracting liquid is filtered through the filter membrane and then injected into the interior of the solution tank 3. Then the fixing seat 7 is pulled down, and the fixing seat 7 drives the connecting rod 6 and the slide 93 to move downward. The slide 93 will slide along the connecting sleeve 5, and the slide 93 will drive the card ball 92 to move. The card ball 92 will roll along the arc surface of the card slot 91. The card ball 92 will be squeezed and move horizontally. The card ball 92 will drive the support block 94 to move, and the support block 94 will squeeze the first The second spring 95 can then separate the card ball 92 from the card slot 91. As the slide 93 moves downward, the card ball 92 can be pushed into the card slot 91 at another position under the elastic action of the second spring 95. At this time, the relative positions of the slide 93 and the connecting sleeve 5 can be fixed. At the same time, the sensor 10 will move downward and extend into the solution tank 3. The probe of the sensor 10 will contact the solution for detection. The enzyme-free electrode will contact the sample solution. The target pesticide molecules are captured by the molecular imprinting layer, causing the charge distribution on the electrode surface to change, so that the pesticide residues can be detected. The detection operation is convenient and fast.

[0029] When the sensor 10 needs to be disassembled, the sensor 10 is directly rotated. The arc surface of the arc groove 86 inside the sensor 10 will squeeze and push the arc block 85, and the arc block 85 will slide outward. The arc block 85 will drive the slider 83 and the push rod 84 to move. The slider 83 will slide along the fixed rod 81 and squeeze the first spring 82, so that the arc block 85 can be separated from the arc groove 86. Then the sensor 10 can be pulled out from the fixing seat 7, which is convenient for disassembly of the sensor 10 and its inspection and maintenance.

[0030] The technical effect of this solution is that: by designing the solution tank 3, the solution to be tested can be stored, and the slide 93 and the connecting sleeve 5 can be relatively connected and fixed by plugging the card ball 92 into the card slot 91. When the fixed seat 7 is pulled down, the slide 93 can be driven to move downward, and the card ball 92 can be plugged into the card slot 91 at another position. At this time, the height of the sensor 10 will drop, and the sensor 10 probe can contact the solution to detect pesticide residues in the solution. The detection operation is convenient and fast. By designing the connection between the arc block 85 and the arc groove 86 inside the sensor 10 shell, the sensor 10 can be limited, and the connection and fixation of the sensor 10 and the fixing seat 7 can be achieved. The arc block 85 and the arc groove 86 can be separated by rotating the sensor 10, and the sensor 10 can be pulled out from the inside of the fixing seat 7, which facilitates the disassembly of the sensor 10 and facilitates its inspection and maintenance.

[0031] In another embodiment, the electrode substrate utilizes a 4mm diameter disc-shaped gold electrode (a glassy carbon electrode may also be used). Its edges are rounded with a 0.5mm radius and polished to a mirror finish using Al2O3 polishing powder (particle size 0.05μm). Gold electrodes are used due to their excellent conductivity, high chemical stability, and ease of surface modification with molecular imprinting layers. The rounded edge design prevents solution residue from forming in corners, ensuring repeatable detection. The mirror polish reduces interference from electrode surface roughness on charge distribution, improving signal stability.

[0032] Taking the detection of organophosphorus pesticides (such as malathion) as an example, the preparation steps of the molecular imprinting layer are as follows: 0.3 mol / L functional monomer methacrylic acid (providing carboxyl functional groups to form hydrogen bonds with the amino groups of malathion), 0.1 mol / L cross-linker ethylene glycol dimethacrylate, and 0.15 mol / L malathion template molecules are mixed in a molar ratio of 2:1:1, dissolved in 0.1 mol / L phosphate buffer (pH = 7.0), and degassed by ultrasonication for 10 minutes; The above-mentioned mixed solution was added dropwise to the surface of the gold electrode, and a DC voltage of 1.0V was applied on the potentiostat. The electropolymerization was continued for 20 minutes. At this time, the functional monomer and the cross-linker formed a polymer film on the electrode surface; the electrode was placed in a methanol-acetic acid mixture with a volume ratio of 9:1, and ultrasonic elution was performed for 30 minutes to remove the malathion template molecules, and finally a porous recognition channel matching the size and configuration of the malathion molecules was formed on the polymer film.

[0033] The prepared molecular imprinting layer is a circular film covering the electrode surface with a thickness of about 120nm. The surface has porous channels with a diameter of 20-30nm. The exposed carboxyl functional groups on the inner wall of the channel can specifically recognize and bind to malathion molecules.

[0034] The conductive probe is a 0.8mm diameter copper probe (gold-plated on the surface to enhance conductivity). Its lower end is vertically embedded in the center of the electrode substrate, making close contact with the bottom of the molecular imprinted layer (contact area of ​​approximately 0.5mm²). The upper end penetrates the sensor's polytetrafluoroethylene insulating shell (shell thickness 2mm) and is fixedly connected to the copper core (diameter 0.3mm) of the transmission line by soldering. The outer layer of the transmission line is wrapped with a shielding layer to reduce electromagnetic interference.

[0035] When the sensor probe contacts the test solution, malathion molecules in the solution diffuse into the porous channels of the molecularly imprinted layer (MIL) and specifically bind to the carboxyl functional groups on the channel walls. This alters the charge distribution on the electrode surface, which in turn causes a change in the electrode potential (relative to the reference electrode). This potential change is transmitted to the control module via the conductive probe and transmission line, where signal conversion reflects the pesticide residue concentration. The porous structure and specific functional groups of the MIL ensure high selectivity for the target pesticide, while the excellent conductivity of the gold electrode ensures efficient signal transmission.

[0036] Through the above-mentioned structural design, the specific recognition ability of the sensor is improved compared with traditional non-imprinting sensors, and the detection limit can reach 0.01 mg / kg; the close connection between the gold electrode and the conductive probe makes the signal transmission loss rate low, ensuring the detection accuracy; the detachable molecular imprinting layer (which can be repolymerized after being peeled off by chemical methods) extends the service life of the sensor and reduces the detection cost.

[0037] Control modules (such as Figure 5 The signal acquisition unit (shown in Figure 1) utilizes a 24-bit A / D converter (sampling frequency 200Hz), the environmental compensation unit incorporates a built-in SHT30 temperature and humidity sensor (measurement accuracy ±0.5°C, ±2%RH), and the data processing unit utilizes an STM32H743 microprocessor, capable of running complex algorithms in real time. For the detection of malathion residues in vegetable extracts, the standard testing temperature is 25°C and the standard humidity is 50%RH. The sensor operates with a pulsed voltage (0.4V for 1s, 0V for 0.2s, five cycles), and the cleaning voltage is 1.8V for 2s.

[0038] During detection, the signal acquisition unit receives the voltage signal V(t) output by the sensor from t1=0s to t2=5s, and calculates the integral signal value U according to formula (1):

[0039] Assuming that the voltage signal V(t) changes with time during the detection process as V(t)=0.1+0.02t (unit: V), substituting it into the formula yields:

[0040] Time integration processing can effectively eliminate instantaneous noise and enhance signal stability.

[0041] Substituting U = 0.48 into formula (2) (where a = -0.03, b = 0.002, c = 0.05), we get the initial concentration C0:

[0042] Assume that the interval between this test and the previous test is Δt = 15 minutes, the final concentration of the previous test C before = 0.06 mg / kg, and the ambient humidity before this test H = 35% RH. The specific interference treatment is as follows: Since 10min≤Δt=15min<30min, the time decay factor f(t) is calculated according to formula (3):

[0043] The calculated difference ΔC = - 0.06 = 0.02 mg / kg. Since Cpre = 0.06 mg / kg ≤ 0.1 mg / kg, the threshold is 0.2 mg / kg, ΔC < the threshold, and there is no need to trigger an abnormal warning. According to formula (4), k difference = 1.

[0044] Calculate the humidity influence coefficient kwet according to formula (5) (because H=35%RH<50%RH):

[0045] Humidity integral calculation: The humidity remains constant at 35%RH during the recording interval of the environmental compensation unit (15 minutes), so the humidity integral value is:

[0046] Substituting the above parameters into formula (6), the final detection concentration Cfinal is obtained:

[0047] If the sensor's factory calibration baseline Vmark = 0.2V, and the baseline voltage Vbase after cleaning after a certain test is 0.29V, Vbase - Vmark = 0.09V> 8mV, the control module triggers a maintenance prompt to remind the user to replace the molecular imprinting layer or recalibrate the electrode.

[0048] The control module enhances signal anti-interference capabilities through time integration. It corrects residual interference using an interval attenuation factor (shorter intervals result in stronger correction). It identifies abnormal fluctuations based on historical data differences (a larger difference is allowed for high residual concentrations). It also compensates for the effects of water evaporation on solution concentration through humidity integration and real-time humidity (compensation is more significant at low humidity and long time intervals). Finally, through multi-parameter coupled calculations, it outputs the accurate concentration value after eliminating interference.

[0049] This logical AND formula can reduce the relative error of continuous detection, improve the compensation effect for changes in ambient humidity (30%-70% RH), and increase the cross-interference elimination rate within a 10-minute interval, significantly improving the system's detection stability and accuracy in complex scenarios.

[0050] The above is only an embodiment of the present invention, and the common knowledge such as the specific structure and characteristics of the scheme is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A rapid pesticide residue detection system based on a non-enzyme sensor, comprising a base plate, characterized in that: The bottom of the base plate is fixedly connected to a plurality of evenly distributed anti-slip pads, the top of the base plate is fixedly connected to a solution tank, the upper end of the base plate and the left side of the solution tank is fixedly connected to a bracket, the lower end of the bracket is fixedly connected to a connecting sleeve, the internal sliding sleeve of the connecting sleeve is connected to a connecting rod, the bottom of the connecting rod is fixedly connected to a fixing seat, the internal sliding sleeve of the fixing seat is connected to a sensor, a transmission line is provided on the top of the sensor, a connecting mechanism is provided on the sensor, and a moving mechanism is provided on the connecting sleeve.

2. The rapid pesticide residue detection system based on enzyme-free sensor according to claim 1 is characterized in that: The connecting mechanism includes a fixing rod, two symmetrically distributed fixing rods are fixedly connected to the inside of the fixing seat, a first spring is provided on the outside of the fixing rod, a slider is slidably sleeved on the outside of the fixing rod, the slider is slidably connected to the fixing seat, a push rod is fixedly connected to the top of the slider, the push rod is slidably connected to the fixing seat, an arc block is fixedly connected to the bottom of the slider, the arc block is slidably connected to the fixing seat, and the arc block is slidably connected to the sensor.

3. The rapid pesticide residue detection system based on enzyme-free sensor according to claim 2 is characterized in that: One end of the first spring is fixedly connected to the slider, and the other end of the first spring is fixedly connected to the fixing seat.

4. The rapid pesticide residue detection system based on enzyme-free sensor according to claim 1 is characterized in that: An arc-shaped groove is provided inside the sensor, and an arc-shaped block is slidably connected inside the arc-shaped groove.

5. The rapid pesticide residue detection system based on enzyme-free sensor according to claim 1 is characterized in that: The moving mechanism includes a card slot, a card slot is opened inside the connecting sleeve, the card slot is movably sleeved with a card ball inside, the outer side of the card ball is movably sleeved with a slide, the slide is slidably connected to the connecting sleeve, the slide is fixedly connected to the connecting rod, the outer side of the card ball is movably sleeved with a support block, the support block is slidably connected to the slide, and a second spring is provided inside the slide.

6. The rapid pesticide residue detection system based on enzyme-free sensor according to claim 5, characterized in that: There are multiple card slots, and the multiple card slots are evenly distributed inside the connecting sleeve.

7. The rapid pesticide residue detection system based on enzyme-free sensor according to claim 5, characterized in that: One end of the second spring is fixedly connected to one of the support blocks, and the other end of the second spring is fixedly connected to the other support block.

8. The enzyme-free sensor-based rapid pesticide residue detection system according to claim 7, characterized in that: The sensor comprises an electrode matrix, a molecular imprinting layer and a conductive probe connected in sequence, wherein the electrode matrix is ​​a disc-shaped structure with a diameter of 3-5 mm, the edge of which is in an arc transition and the surface is polished; The molecularly imprinted layer is a circular film covering the upper surface of the electrode substrate with a thickness of 50-200 nm. The surface of the film is distributed with porous recognition channels with a diameter of 10-50 nm. The inner wall of the channel is modified with functional groups complementary to the target pesticide molecules. The molecularly imprinted layer is prepared by an electropolymerization method: using the target pesticide molecule as a template, 0.1-0.5 mol / L functional monomer, 0.05-0.2 mol / L cross-linking agent, and the template molecule are dissolved in a 0.1 mol / L phosphate buffer at a molar ratio of 2:

1. A constant voltage of 0.8-1.2 V is applied to the electrode substrate for electropolymerization for 15-25 minutes. After the polymerization is completed, the template molecule is eluted with a methanol-acetic acid mixed solution with a volume ratio of 9:1 to form a specific recognition structure; The conductive probe is a copper probe with a diameter of 0.5-1 mm. Its lower end is vertically embedded in the center of the electrode substrate and contacts the bottom of the molecular imprinted layer. The upper end passes through the insulating shell of the sensor and is welded to the core wire of the transmission line.

9. The rapid pesticide residue detection system based on enzyme-free sensor according to claim 8, characterized in that: The end of the transmission line away from the sensor is connected to a control module, which includes a signal acquisition unit, a data processing unit, an interference elimination unit and an environmental compensation unit, and the environmental compensation unit has a built-in temperature and humidity sensor; The signal acquisition unit receives the electrical signal output by the sensor through the transmission line, converts it into a digital signal through a 24-bit A / D converter, and performs time integration processing according to Formula 1 to obtain the integrated signal value U: in, is the instantaneous voltage signal at time t, is the detection start time, The end time of the test, is the signal attenuation coefficient; The data processing unit substitutes the integrated signal value U into the concentration-response model to obtain the initial concentration value C0: Wherein, a, b, and c are calibration coefficients obtained by experimental fitting of standard solutions; The interference elimination unit sets the interval between two detections as Δt. If Δt < 10 min, the residual interference correction is enabled. If 10 min ≤ Δt < 30 min, the time attenuation factor f(t) is calculated according to formula (3): If Δt ≥ 30 min, the residual interference is considered negligible and C0 is directly used as the intermediate value; Then, the final concentration value C before the last test is obtained, and the difference between the initial concentration value C0 and C before is calculated as ΔC = C0 - C before. If ΔC > 2 × C before or ΔC > 0.2 mg / kg, an abnormal fluctuation warning is triggered, and the difference correction coefficient k difference is introduced according to formula (4): The environmental compensation unit obtains the detection environment humidity H and calculates the humidity influence coefficient kwet according to formula (5): 50%RH is the standard humidity. When H>50, kwet=1. The detection concentration C finally output by the control module is calculated according to formula (6): in, The last detection end time. The start time of this test. is the humidity integral value during the interval; The control module outputs a pulsed operating voltage to the sensor through the transmission line, and outputs a 1.8V reverse cleaning voltage after each test. At the same time, it records the baseline voltage Vbase after cleaning. If Vbase - Vmark is greater than 8mV for three consecutive tests, and Vmark is the factory calibration baseline, a sensor maintenance prompt is triggered.

10. A method for rapid detection of pesticide residues based on a non-enzyme sensor, characterized in that: A system as claimed in any one of claims 1 to 7 is employed.

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