Edible flower pesticide residue detection device and detection method thereof

Abstract

The invention provides an edible fresh flower pesticide residue detection device and a detection method and device thereof, and relates to the technical field of agricultural product detection, the edible fresh flower pesticide residue detection device comprises a housing, a sampling assembly, a detection assembly and a control unit; the sampling assembly adopts a disposable hydrogel sampling piece, is composed of a composite hydrogel matrix containing Raman active nanoparticles, and is used for non-destructively transferring and enriching pesticide residues on the surfaces of petals; the detection assembly adopts a non-dispersive optical system comprising an excitation light source, a narrow-band filter array corresponding to a target pesticide characteristic Raman peak and a single-point photoelectric detector array to perform targeted detection on a Raman signal with a specific wavelength; according to the method, nondestructive efficient sampling of fragile petals is achieved through the specially-made hydrogel sampling piece, the equipment cost is greatly reduced through a non-dispersive optical framework, the problem that an existing detection method cannot give consideration to on-site pre-screening of rapid, low-cost, portable and nondestructive detection is solved, and the method is suitable for rapid detection of commercial tenants, markets and supervision departments.

Description

Technical Field

[0001] This invention belongs to the field of agricultural product testing technology, specifically relating to a device and method for detecting pesticide residues in edible fresh flowers. Background Technology

[0002] In recent years, edible flowers have become increasingly popular in catering and daily consumption due to their unique flavor and aesthetic value. However, their food safety issues have also attracted growing attention. Most flowers circulating in the market were originally cultivated as ornamental plants, and the types and dosage standards of pesticides allowed to be used in their cultivation differ significantly from those for edible agricultural products, potentially exceeding food safety limits. If these ornamental flowers containing excessive pesticide residues enter the food chain, they will pose a potential threat to consumers' health.

[0003] Currently, conventional methods for detecting pesticide residues, such as QuEChERS pretreatment technology combined with gas chromatography-mass spectrometry, while providing accurate and reliable results, suffer from drawbacks such as expensive equipment, complex operating procedures, and long detection cycles. These methods cannot meet the needs for large-scale, high-timeliness on-site screening in fields, wholesale markets, and merchant procurement.

[0004] Surface-enhanced Raman spectroscopy (SERS) is a highly sensitive and rapid detection technology. However, most Raman spectrometers on the market use traditional spectroscopic systems and area array detectors to obtain complete Raman spectra of substances, resulting in high costs and making it difficult to widely apply in the agricultural field. In addition, the petals of edible flowers are fragile and easily damaged, and are rich in pigments and other substances that can easily cause fluorescence interference. Traditional sample collection and detection methods cannot achieve both non-destructive sampling and detection accuracy. Summary of the Invention

[0005] To overcome the problems in the prior art, this invention develops a pesticide residue detection device and method for edible flowers, providing a pesticide residue pre-screening solution that is easy to operate, can perform non-destructive and rapid surface sampling of edible flowers, and effectively suppresses interference.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: A pesticide residue detection device for edible fresh flowers includes a housing, a sampling component, a detection component, and a control unit; the top of the housing is an operating table, and a base is provided on the operating table, with a detection hole communicating with the bottom of the base. The sampling assembly includes a sample stage and a hydrogel sampling sheet. The sample stage is installed above the detection hole of the base, and the hydrogel sampling sheet is replaceably installed on the sample stage. The hydrogel sampling sheet includes a base layer and a Raman composite hydrogel layer. The detection component is installed in the housing below the detection hole. The detection component includes an excitation light source for exciting the hydrogel sampling sheet, a collection optical path for receiving Raman scattered light from the hydrogel sampling sheet, a filter module coupled to the collection optical path, and a detection module for receiving the light signal filtered by the filter module. The control unit is connected to the detection module.

[0007] Furthermore, the Raman composite hydrogel layer is composed of a composite hydrogel matrix of polyvinyl alcohol, Raman-active nanoparticles, and chitosan.

[0008] Furthermore, the Raman composite hydrogel layer has a sandwich-like structure.

[0009] Furthermore, the sample stage is equipped with a flip-grip for mounting the hydrogel sampling sheet. The flip-grip, through a universal joint structure or a rotating shaft, flips the hydrogel sampling sheet to an upward sampling position or a downward detection position aligned with the detection hole.

[0010] Furthermore, the excitation source is a bulk Bragg grating frequency-stabilized semiconductor laser with a wavelength of nm.

[0011] Furthermore, the filtering module includes a narrowband filter corresponding to the characteristic Raman peak wavelength of the target pesticide, and the detection module includes a single-point photodetector corresponding to the filtering module.

[0012] Furthermore, the control unit is configured to execute a baseline correction algorithm and stores signal strength threshold calibration data for the target pesticide.

[0013] A method for detecting pesticide residues in edible fresh flowers using the aforementioned detection device includes the following steps: S1. Fix the hydrogel sampling sheet onto the sample stage mounted on the base; S2. Contact the hydrogel sampling sheet from S1 with the surface of the petals of the edible flower to be tested to transfer pesticide residues on the surface; S3. Transfer the hydrogel sample taken from S2 on the sample stage to the testing station; S4. Start the control switch, and the control unit controls the excitation light source to irradiate the hydrogel sampling sheet, and the detection module collects the light signal intensity at multiple discrete wavelengths corresponding to the Raman peaks of the target pesticide. S5. The control unit processes the collected signal strength, determines the presence or risk level of the target pesticide, and outputs the results.

[0014] The beneficial effects of this invention are: 1. This invention replaces the expensive and complex spectrometer system with a non-dispersive optical architecture of excitation light source + narrowband filter + single-point detector, and performs targeted detection of the characteristic peaks of several key pesticides, thereby reducing equipment manufacturing costs and facilitating widespread adoption.

[0015] 2. This invention designs a hydrogel sampling sheet for fragile samples such as petals. Its composite matrix has both flexibility and bioadhesion, which can efficiently transfer and enrich pesticide residue molecules on the surface without damaging the sample, thus improving detection sensitivity. The design of the clip-on structure further improves the sampling efficiency and representativeness of petal samples.

[0016] 3. The integrated design of this invention closely combines the sampling and testing processes. Users only need to place, touch, position and start the operation to obtain screening results in a short time, which is very suitable for field applications. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of this application; Figure 2 This is a schematic diagram of the operating console structure of this application; Figure 3 This is a schematic diagram of the sampling component structure in this application; Figure 4 This is a schematic diagram of the flip-grip structure of this application; Figure 5 This is a schematic diagram of the hydrogel sampling sheet structure of this application; Figure 6 This is a schematic diagram of the detection component structure in this application; Figure 7 This is a front view structural diagram of the internal detection component of the housing in this application; Figure 8 This is a schematic diagram of the rear structure of the housing in this application.

[0018] Figure label: 1-Casing, 11-Operating table, 12-Base, 13-Detection hole; 2-Sampling assembly, 21-Sample stage, 211-Flip clamping component, 22-Hydrogel sampling sheet, 221-Base layer, 222-Raman composite hydrogel layer; 3-Detection component, 31-Excitation source, 32-Collection optical path, 33-Filter module, 331-Narrowband filter, 34-Detection module, 341-Single-point photodetector; 4-Control unit. Detailed Implementation

[0019] To make the objectives, technical solutions, and beneficial effects of the present invention clearer, the preferred embodiments of the present invention will be described in detail below to facilitate understanding by those skilled in the art.

[0020] See Figure 1 , Figure 2 , Figure 8The present invention provides a pesticide residue detection device for edible flowers, including a compact and portable housing 1, and a sampling component 2, a detection component 3 and a control unit 4 disposed inside or on the surface therein. The top of the housing 1 is designed as an operating table 11 for easy operation by the user. A base 12 is fixed on the operating table 11, and a detection hole 13 is opened on the base 12. The detection hole 13 penetrates the operating table 11 so that the inner and outer spaces of the housing 1 are optically connected. See Figure 1 , Figure 3 , Figure 4 , Figure 5 The core function of the sampling component 2 is to carry the disposable hydrogel sampling sheet 22 and complete the collection of pesticide residues. The sampling component 2 includes a sample stage 21 that can be installed on the base 12 and is located directly above the detection hole 13. The hydrogel sampling sheet 22 is installed on the sample stage 21 in a replaceable manner. The hydrogel sampling sheet 22 consists of two parts: a flexible base layer 221 that provides support, and a Raman composite hydrogel layer 222 coated or bonded to the base layer 221. The Raman composite hydrogel layer 222 is preferably composed of a composite hydrogel matrix of polyvinyl alcohol, Raman-active nanoparticles and chitosan. The composite matrix composed of polyvinyl alcohol and chitosan has excellent flexibility and biomimetic adhesion, which can closely conform to the microstructure of the petal surface and efficiently transfer pesticide residue molecules on the surface without damaging the petal. The Raman-active nanoparticles, such as silver nanoparticles or gold nanoparticles, are uniformly fixed in the hydrogel network through in-situ synthesis technology, serving as an enhancing substrate for the SERS effect. See Figure 5 Furthermore, to better suit the thinness of the petals, the Raman composite hydrogel layer 222 is designed as a folded clip structure. When in use, the edge of the petal is inserted into the clip, enabling double-sided sampling in one operation, which improves sampling efficiency and representativeness.

[0021] See Figure 3 , Figure 4In a preferred embodiment, a flip-grip 211 is specially provided on the sample stage 21 for directly mounting the hydrogel sampling piece 22. The flip-grip 211 is connected to the sample stage 21 via a universal joint structure or a rotating shaft, allowing the flip-grip 211 to switch between two positions: one is an upward sampling position, where the user can easily mount the sampling piece and sample the petals; the other is a downward detection position aligned with the detection hole 13. After sampling, the user only needs to flip the gripper 180 degrees to accurately place the hydrogel sampling piece 22 with pesticide residues at the focal point of the detection optical path without manual alignment, greatly simplifying the operation and ensuring the repeatability of the detection. In other embodiments, the sample stage 21 can also be a simple slot-type or open-hole stage, where the user manually inserts or places the sampling piece into the detection position after sampling.

[0022] See Figure 6 , Figure 7 The detection component 3 is integrated and installed inside the housing 1, directly below the detection port 13. The detection component 3 as a whole constitutes a non-dispersive photometer system, including: Excitation source 31: preferably a volume Bragg grating frequency-stabilized semiconductor laser with a wavelength of 785nm, which can reduce fluorescence interference caused by natural pigments in the petals, such as anthocyanins. The beam emitted by the excitation source 31 passes vertically upward through the detection hole 13 after being adjusted by the optical path system and is focused on the hydrogel sampling piece 22 at the detection station. Collection optical path 32: Collects the Raman scattered light generated after the sample is excited. In this embodiment, the collection optical path can share some components with the excitation optical path. For example, a dichroic mirror is used to separate the excitation optical path from the signal collection optical path, and a lens group is used to collect and collimate the scattered light. Filter module 33: Enables low-cost targeted detection. The filter module 33 does not use a continuously split grating, but contains one or more fixed narrowband filters 331. The center transmission wavelength of each narrowband filter 331 precisely corresponds to a characteristic Raman peak of a specific target pesticide. For example, when detecting thiram, a filter with a center wavelength corresponding to its 1381 cm⁻¹ Raman peak is configured. Detection module 34: This module works closely with the filter module 33. It contains multiple single-point photodetectors 341, the number and position of which correspond one-to-one with the narrowband filter 331. Each detector 341 is specifically responsible for receiving the light signal that passes through the corresponding narrowband filter in front of it and converting its intensity into an electrical signal. In order to detect weak Raman signals, the single-point photodetector 341 is preferably a high-gain silicon photomultiplier tube.

[0023] See Figure 6 , Figure 7The control unit 4 integrates a microprocessor and is electrically connected to all the single-point photodetectors 341 of the detection module 34. The control unit 4 is responsible for driving the entire system and processing data. The software configuration of the control unit 4 is to execute a baseline correction algorithm, which can automatically remove any residual fluorescence background that may exist in the signal and extract the pure Raman peak signal intensity. In addition, the memory of the control unit 4 pre-stores the signal intensity threshold calibration data of the target pesticide. By comparing the measured signal intensity with these thresholds, it is possible to quickly determine whether the pesticide residue exceeds the standard and give semi-quantitative or qualitative conclusions such as "not detected", "trace amount", and "risk of exceeding the standard".

[0024] Based on a pesticide residue detection device for edible fresh flowers, a specific implementation process of the method of the present invention is as follows: S1: The operator fixes a new disposable hydrogel sampling sheet 22 onto the sample stage 21 at the sampling position, such as the flip clamp 211. S2: The operator uses a tool to hold the flower to be tested and makes full contact between the surface of its petals and the Raman composite hydrogel layer 222 of the hydrogel sampling sheet 22 for 15-30 seconds to complete the transfer and enrichment of pesticide residues on the surface. S3: The operator flips or moves the sample stage 21 carrying the sample from the sampling station to the testing station, so that the hydrogel sampling sheet 22 is aligned with the testing hole 13 below. S4: When the operator presses the start control switch on the device, the control unit 4 receives the instruction and automatically controls the excitation light source 31 to turn on and irradiate the sample. At the same time, the detection module 34 collects the light signal intensity data passing through each narrowband filter 331 within a preset integration time. S5: After the data acquisition is completed, the control unit 4 automatically performs baseline correction and other processing on the data, compares the processed signal strength with the built-in threshold database, and finally displays the detection results of the target pesticide on the device's display screen, or sends detailed data to a mobile app via Bluetooth.

[0025] In summary, this invention provides a complete, on-site rapid pre-screening solution for pesticide residues in edible fresh flowers through innovative hydrogel sampling sheets, a unique sample stage structure, and a low-cost non-dispersive optical detection system.

[0026] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A device for detecting pesticide residues in edible fresh flowers, characterized in that, It includes a housing (1), a sampling component (2), a detection component (3) and a control unit (4); the top of the housing (1) is an operating table (11), and a base (12) is provided on the operating table (11). A detection hole (13) communicating with the bottom of the base (12) is opened in the base (12). The sampling assembly (2) includes a sample stage (21) and a hydrogel sampling sheet (22). The sample stage (21) is installed above the detection hole (13) of the base (12). The hydrogel sampling sheet (22) can be replaced and installed on the sample stage (21). The hydrogel sampling sheet (22) includes a base layer (221) and a Raman composite hydrogel layer (222). The detection component (3) is installed in the housing (1) below the detection hole (13). The detection component (3) includes an excitation light source (31) for exciting the hydrogel sampling sheet (22), a collection optical path (32) for receiving the Raman scattered light from the hydrogel sampling sheet (22), a filter module (33) coupled to the collection optical path (32), and a detection module (34) for receiving the light signal filtered by the filter module (33). The control unit (4) is connected to the detection module (34).

2. The pesticide residue detection device for edible fresh flowers according to claim 1, characterized in that, The Raman composite hydrogel layer (222) is composed of a composite hydrogel matrix of polyvinyl alcohol, Raman-active nanoparticles and chitosan.

3. The pesticide residue detection device for edible fresh flowers according to claim 2, characterized in that, The Raman composite hydrogel layer (222) has a sandwich-like structure.

4. The pesticide residue detection device for edible fresh flowers according to claim 1, characterized in that, The sample stage (21) is provided with a flip clamp (211) for installing the hydrogel sampling piece (22). The flip clamp (211) flips the hydrogel sampling piece (22) to the sampling position facing upward or the detection position facing downward aligned with the detection hole (13) through the universal joint structure (221) or the rotating shaft.

5. The pesticide residue detection device for edible fresh flowers according to claim 1, characterized in that, The excitation source (31) is a bulk Bragg grating frequency-stabilized semiconductor laser with a wavelength of 785nm.

6. The pesticide residue detection device for edible fresh flowers according to claim 1, characterized in that, The filter module (33) includes a narrowband filter (331) corresponding to the characteristic Raman peak wavelength of the target pesticide, and the detection module (34) includes a single-point photodetector (341) corresponding to the filter module (33).

7. The pesticide residue detection device for edible fresh flowers according to claim 1, characterized in that, The control unit (4) is configured to execute a baseline correction algorithm and stores the signal strength threshold calibration data of the target pesticide.

8. A method for detecting pesticide residues in edible fresh flowers using the detection device according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Fix the hydrogel sampling sheet (22) onto the sample stage (21) mounted on the base (12); S2. The hydrogel sampling sheet (22) of S1 is brought into contact with the surface of the petals of the edible flower to be tested to transfer the pesticide residue on the surface; S3. Transfer the hydrogel sample (22) taken after S2 on the sample stage (21) to the testing station; S4. Start the control switch, and the control unit (4) controls the excitation light source (31) to irradiate the hydrogel sampling sheet (22), and the detection module (34) collects the light signal intensity at multiple discrete wavelengths corresponding to the Raman peaks of the target pesticide. S5. The control unit (4) processes the collected signal strength, determines the presence or risk level of the target pesticide, and outputs the results.

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