Remote detection system and detection method based on optical fiber surface enhanced Raman scattering

Abstract

The remote detection system based on optical fiber surface enhanced Raman scattering disclosed in the present invention includes a detection box, a total optical fiber bundle, a first optical fiber beam splitter, a second optical fiber beam splitter, a first filter, a second filter, a semiconductor laser, a Raman spectrometer and a computer. The detection box includes an input interface, an output interface, a QR code and a reagent kit. The output end of the semiconductor laser is connected to the input interface via the first filter, the third bifurcated optical fiber, and the first bifurcated optical fiber in sequence. The output interface is connected to the input end of the Raman spectrometer via the second bifurcated optical fiber, the fourth bifurcated optical fiber, and the second filter in sequence. The output end of the Raman spectrometer is connected to the input end of the computer, and the trigger signal output end of the computer is connected to the input end of the semiconductor laser. The system of the present invention has the advantages of home detection, convenient operation, diverse types of substances detected, high detection accuracy, etc., and its detection box has the characteristics of convenient installation and portability, and has broad application prospects in the field of food detection.

Description

Technical Field

[0001] The present invention relates to the technical field of food detection, and in particular to a remote detection system based on optical fiber surface enhanced Raman scattering. Background Art

[0002] Food may contain legally used food additives, or it may contain non-food substances illegally added by unscrupulous businesses. These non-food substances are called illegal food additives. Food problems primarily focus on the use of illegal food additives, the misuse of food additives, and the abuse of pesticides and veterinary drugs. These issues can lead to unsafe and substandard food, which inevitably endangers consumer health. Unsafe food can primarily cause foodborne illnesses, resulting in acute and chronic poisoning, allergies, developmental and reproductive consequences, cancer, malformations, and even death. Consumers cannot intuitively determine whether the food they purchase is healthy and harmless, making the detection of ingredients in food that are harmful to human health particularly important.

[0003] Currently, there are several main methods for testing food ingredients: qualitative test paper method using direct color development of test paper or chromatography; quantitative colorimetric method using colorimetric tubes after reacting with reagents and observing the color of the colorimetric tube; titration method using a dropper bottle filled with a standard solution to titrate the sample and determine the content of the substance being tested based on the number of drops consumed; enzyme-linked immunosorbent assay kit method that allows specific binding reactions between antibodies and antigens. Although each of the above methods has its own advantages and disadvantages, the operation process is relatively complicated, and it is difficult to accurately obtain the type and concentration of the relevant substances added to the food, so the results obtained need to be improved. Due to the preparation of relevant reagents and the need for instruments, users cannot perform quick and convenient testing at home, and even if they use it at home, there are still certain safety risks, and the feasibility is low. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a remote detection system based on optical fiber surface enhanced Raman scattering, which has the advantages of home detection, convenient operation, diverse types of detected substances, and high detection accuracy, in view of the shortcomings of the existing technology.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: a remote detection system based on optical fiber surface enhanced Raman scattering, comprising a detection box, a total optical fiber bundle, a first optical fiber beam splitter, a second optical fiber beam splitter, a first filter, a second filter, a semiconductor laser, a Raman spectrometer and a computer, wherein the detection box is installed in the user's home, the detection box comprises an input interface, an output interface, a QR code and a reagent kit, the QR code is pasted on the detection box, the QR code is used for the user to scan the code to start the remote detection system, the reagent kit is installed in the detection box, the reagent kit is provided with a section of optical fiber waist, the optical fiber waist is made of multimode quartz optical fiber, the surface of the optical fiber waist is silanized, and the surface of the silanized optical fiber waist is adsorbed with star-shaped gold nanoparticles, the gold nanoparticles are wrapped by silica, one end of the optical fiber waist is connected to the input interface via an optical fiber, and the other end of the optical fiber waist is connected to the output interface via an optical fiber, and the total optical fiber bundle is divided into a first bifurcated optical fiber and a second bifurcated optical fiber via the first optical fiber beam splitter. A bifurcated optical fiber is provided. The total optical fiber bundle is split into a third bifurcated optical fiber and a fourth bifurcated optical fiber via the second optical fiber beam splitter. The output end of the semiconductor laser is connected to the input interface via the first filter, the third bifurcated optical fiber, and the first bifurcated optical fiber in sequence. The output interface is connected to the input end of the Raman spectrometer via the second bifurcated optical fiber, the fourth bifurcated optical fiber, and the second filter in sequence. The output end of the Raman spectrometer is connected to the input end of the computer. The trigger signal output end of the computer is connected to the input end of the semiconductor laser. The detection box is used to collect enhanced Raman scattered light signals of a substance to be tested contained in a liquid food or a food soaking liquid obtained by soaking non-liquid food in a 4-mercaptobenzoic acid solution. The Raman spectrometer is used to receive the enhanced Raman scattered light signals, convert the optical signals into electrical signals, and transmit them to the computer. The computer is used to process the electrical signal data to obtain enhanced Raman scattering spectrum data, compare the data with a pre-established database, determine the type and concentration of the tested substance, and ultimately feedback the test results to the user's home.

[0006] Preferably, the laser light emitted from the output end of the semiconductor laser has a wavelength of 785 nm, a power of 2.5 to 10 mW, and a line width of 0.3 nm.

[0007] Preferably, the first bifurcated optical fiber, the second bifurcated optical fiber, the third bifurcated optical fiber and the fourth bifurcated optical fiber are all quartz optical fibers, the transmittance of the first optical fiber beam splitter and the second optical fiber beam splitter is greater than or equal to 95%, the splitting ratio is 50:50, and the splitting ratio deviation is ±8%.

[0008] Preferably, the first filter is a 785nm bandpass filter, and the second filter is a 785nm highpass filter. The first filter allows laser signals with a wavelength of 785nm to pass through. The second filter is used to filter out background light of 785nm and below, while allowing enhanced transmission of Raman scattered light, thereby reducing the impact of background light and improving the accuracy of detection results.

[0009] Preferably, the Raman spectrometer uses a grating with a line count of 800 / mm as a spectroscopic element, the slit width of the system is 20 μm, and the signal-to-noise ratio is higher than 6500:1.

[0010] A detection method implemented using the above-mentioned remote detection system based on optical fiber surface enhanced Raman scattering includes the following steps:

[0011] (1) Preparation of standard solution

[0012] Prepare standard solutions of different concentrations of a substance to be tested;

[0013] (2) Establishment of standard curve

[0014] (2-1) Pour the standard solution of one concentration prepared in step (1) into the reagent box until the reagent box is completely filled;

[0015] (2-2) Scan the QR code on the detection box to start the remote detection system;

[0016] (2-3) The computer triggers the semiconductor laser. The laser light emitted by the semiconductor laser is filtered by the first filter and then emitted into the detection box through the third bifurcated optical fiber, the first bifurcated optical fiber, and the input interface, thereby obtaining an enhanced Raman scattered light signal containing spectral information of the substance to be tested in the test kit. The enhanced Raman scattered light signal enters the second bifurcated optical fiber and the fourth bifurcated optical fiber through the output interface and then enters the second filter. The background light is filtered out by the second filter and then enters the Raman spectrometer. The Raman spectrometer converts the optical signal into an electrical signal and transmits it to the computer. The computer processes the electrical signal data to obtain enhanced Raman scattering spectrum data of the substance to be tested.

[0017] (2-4) Repeat steps (2-1) to (2-3) twice, summarizing the enhanced Raman scattering spectral data of the test substance obtained from the three tests and taking an average value;

[0018] (2-5) Repeat steps (2-1) to (2-4) to obtain the average value of enhanced Raman scattering spectrum data of other test substances with different concentrations;

[0019] (2-6) establishing a linear relationship between the relative peak intensity of the characteristic peak of the substance to be tested and the concentration of the substance to be tested using a least squares fitting method based on the relative peak intensity of the characteristic peak of the substance to be tested and the concentration data of the substance to be tested in the average value data of the enhanced Raman scattering spectrum data obtained;

[0020] (3) repeating steps (1) to (2) to obtain a straight line relationship between the relative peak intensity of 4-mercaptobenzoic acid and other different types of test substances and the concentration of the test substance, summarizing all the concentration relationship straight lines and establishing a database;

[0021] (4) Dissolve 4-mercaptobenzoic acid powder in alcohol and prepare it with ultrapure water to a concentration of 10 -3 mol / L 4-mercaptobenzoic acid solution, repeat steps (2-1) to (2-3) three times, summarize the enhanced Raman scattering spectrum data of 4-mercaptobenzoic acid obtained by the three tests and take the average value to obtain 10 -3 The enhanced Raman scattering spectrum data of the mol / L 4-mercaptobenzoic acid solution is placed into the database established in step (3);

[0022] (5) The user's family will test the liquid food or the liquid food with a concentration of 10 -3 The food soaking liquid obtained by soaking non-liquid food in 10 mol / L 4-mercaptobenzoic acid solution is poured into the test kit. After filling the test kit, scan the QR code on the test box to start the remote detection system. Finally, the computer compares the data in the database based on the relative peak intensity in the enhanced Raman scattering spectrum obtained, determines the type and concentration of the measured substance, and feeds back the test results to the user's home.

[0023] As a preference, before step (5), the user's family first -3 The test kit is filled with a 4-mercaptobenzoic acid solution of 10 mol / L. The QR code on the test kit is scanned to start the remote detection system. The computer compares the data in the database based on the relative peak intensity in the enhanced Raman scattering spectrum obtained. After determining that the test result is 4-mercaptobenzoic acid and its concentration, the test kit is first washed with ultrapure water and then step (5) is performed. Adding the above operation before step (5) can determine the entire system path and ensure that the system can be used normally. In addition, the above operation can detect the optical fiber transmission loss of the user's home, which facilitates the data analysis center to adjust other test data of the home.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] First, the present invention is based on a remote detection system based on fiber-optic surface-enhanced Raman scattering. The detection box is located in the user's home, while the first filter, second filter, semiconductor laser, Raman spectrometer, and other related large-scale instruments can be centrally located in communities, nursing homes, and other areas. The computer can be centrally installed in a data analysis center. Users can use the detection box to perform substance detection at home, and the test results can be fed back to the user's home in a timely manner.

[0026] Second, the present invention provides an optical fiber waist within the detection box to obtain an enhanced Raman scattered light signal containing spectral information of the substance to be tested. The optical fiber waist is made of multimode quartz optical fiber, and star-shaped gold nanoparticles are adsorbed on the surface of the optical fiber waist. The gold nanoparticles are coated with silica. The contact area between the optical fiber waist and the substance to be tested is large, and the power per unit area is low, which makes it difficult to destroy the structure of the gold nanoparticles. At the same time, the star-shaped gold nanoparticles have more tips, which can generate more hot spots at the tips, helping to amplify the Raman signal and overcome the disadvantage of low Raman spectroscopy sensitivity. In addition, the use of silica to coat the gold nanoparticles prevents oxidation of the gold nanoparticles and reduces toxicity.

[0027] 3. The present invention utilizes different characteristic peaks in the Raman scattering spectrum to identify different test substances, and determines the concentration of the test substance based on the fitted standard straight line. It has the advantages of home detection, convenient operation, a variety of test substances, and high detection accuracy. In addition, the detection box used in the detection is easy to install and portable. It has broad application prospects in the field of food testing and is expected to be connected to existing commercial fiber optic networks. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a structural connection block diagram of the remote detection system in Example 1;

[0029] Figure 2 Schematic diagram of the structure of the detection box in Example 1;

[0030] Figure 3 Schematic diagram of the structure of the optical fiber tapered waist in Example 1;

[0031] Figure 4 The 699 cm obtained in Example 2 -1 The relationship between the relative peak intensity of the characteristic peak of melamine and the concentration of melamine is straight line;

[0032] Figure 5 1164cm obtained in Example 2 -1 The linear relationship between the relative peak intensity of the characteristic peak of saccharin sodium and the concentration of saccharin sodium;

[0033] Figure 6 The 1377 cm obtained in Example 2-1 A straight line showing the relationship between the relative peak intensity of the characteristic peak of thiram and the concentration of thiram;

[0034] Figure 7 is the SERS spectrum of 4-MBA;

[0035] Figure 8 This is the SERS spectrum when 4-MBA and thiram exist at the same time. DETAILED DESCRIPTION

[0036] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0037] Example 1: A remote detection system based on optical fiber surface enhanced Raman scattering, such as Figure 1 As shown, it includes a detection box 4, a total optical fiber bundle 5, a first optical fiber beam splitter 6, a second optical fiber beam splitter 7, a first optical filter 8, a second optical filter 9, a semiconductor laser 10, a Raman spectrometer 11 and a computer 12. The detection box 4 is set in the user's home 1, the first optical filter 8, the second optical filter 9, the semiconductor laser 10, and the Raman spectrometer 11 are centrally placed in areas such as communities and nursing homes 2, and the computer 12 is centrally installed in a data analysis center 3. Figure 2 As shown, the detection box 4 includes an input interface 41, an output interface 42, a QR code 43 and a reagent kit 44. The QR code 43 is affixed to the detection box 4. The QR code 43 is used for the user to scan the code to start the remote detection system. The reagent kit 44 is arranged in the detection box 4. The reagent kit 44 is provided with a fiber optic waist 45 with a length of 2 to 3 cm. The fiber optic waist 45 is made of multi-mode quartz fiber. The surface of the fiber optic waist 45 is silanized. The surface of the silanized fiber optic waist 45 is adsorbed with star-shaped gold nanoparticles 46, as shown in FIG. Figure 3As shown, gold nanoparticles 46 are wrapped by silica, one end of the optical fiber waist 45 is connected to the input interface 41 via an optical fiber, and the other end of the optical fiber waist 45 is connected to the output interface 42 via an optical fiber. The first bifurcated optical fiber 61 and the second bifurcated optical fiber 62 are separated from the total optical fiber bundle 5 via a first optical fiber splitter 6, and the third bifurcated optical fiber 71 and the fourth bifurcated optical fiber 72 are separated from the total optical fiber bundle 5 via a second optical fiber splitter 7. The output end of the semiconductor laser 10 is connected to the input interface 41 via the first filter 8, the third bifurcated optical fiber 71, and the first bifurcated optical fiber 61 in sequence, and the output interface 42 is connected to the input end of the Raman spectrometer 11 via the second bifurcated optical fiber 62, the fourth bifurcated optical fiber 72, the second filter 9 in sequence. The output end of the Raman spectrometer 11 is connected to the input end of the computer 12, and the trigger signal output end of the computer 12 is connected to the input end of the semiconductor laser 10. The detection box 4 is used to collect the enhanced Raman scattered light signal of the substance to be tested contained in the liquid food or the food soaking liquid obtained after soaking the non-liquid food with 4-mercaptobenzoic acid solution. The Raman spectrometer 11 is used to receive the enhanced Raman scattered light signal, convert the light signal into an electrical signal, and then transmit it to the computer 12. The computer 12 is used to process the electrical signal data, obtain enhanced Raman scattering spectrum data and perform data comparison in a pre-established database to determine the type and concentration of the substance to be tested, and finally feed back the test results to the user family 1.

[0038] In Example 1, the optical fiber waist 45 is prepared using the known oxyhydrogen flame heating-stepper motor stretching method and subjected to conventional silanization treatment. The multimode quartz optical fiber used has a core diameter of 105 microns, a cladding thickness of 20 microns, and a total core and cladding diameter of 125 microns, which has the effect of enhancing the evanescent wave.

[0039] In Example 1, the laser emitted from the output end of the semiconductor laser 10 has a wavelength of 785 nm, a power of 2.5 to 10 mW, and a linewidth of 0.3 nm; the first bifurcated optical fiber 61, the second bifurcated optical fiber 62, the third bifurcated optical fiber 71, and the fourth bifurcated optical fiber 72 are all quartz optical fibers; the transmittance of the first optical fiber beam splitter 6 and the second optical fiber beam splitter 7 is greater than or equal to 95%, the splitting ratio is 50:50, and the splitting ratio deviation is ±8%; the first filter 8 is a 785 nm bandpass filter, and the second filter 9 is a 785 nm high-pass filter; the Raman spectrometer 11 uses a grating with a groove count of 800 / mm as a splitting element, the slit width of the system is 20 μm, and the signal-to-noise ratio is higher than 6500:1.

[0040] Examples of the illegal use of food additives, the misuse of food additives, and the abuse of pesticides and veterinary drugs are well-known in daily life, including melamine in milk, sodium saccharin in liquor, and thiram residues on the surfaces of vegetables and fruits. Melamine, an organic compound, can damage kidney function, leading to acute renal failure and even death; sodium saccharin, a sweetener, is indigestible and can cause cancer if accumulated in excess; and thiram, an insecticide, is moderately toxic upon ingestion and highly toxic upon inhalation. In Example 2 below, the present method is used to detect these three substances.

[0041] Example 2: A detection method implemented using the remote detection system based on optical fiber surface-enhanced Raman scattering of Example 1 includes the following steps:

[0042] (1) Preparation of standard solution

[0043] (1-1) Accurately weighing 10 parts of melamine, dissolving them in the same amount of milk, respectively, to prepare melamine-milk solutions with concentrations of 0.2 mg / L, 0.5 mg / L, 1.0 mg / L, 2.0 mg / L, 3.0 mg / L, 4.0 mg / L, 5.0 mg / L, 6.0 mg / L, 8.0 mg / L, and 10.0 mg / L, respectively, as melamine standard solutions;

[0044] (1-2) Accurately weigh 10 parts of saccharin sodium and dissolve them in the same liquor to prepare saccharin sodium liquor solutions with concentrations of 40 mg / L, 20 mg / L, 10 mg / L, 8 mg / L, 6 mg / L, 4 mg / L, 2 mg / L, 1 mg / L, 0.8 mg / L, and 0.5 mg / L, respectively, as standard solutions of saccharin sodium;

[0045] (1-3) 10 parts of thiram were mixed with 10 -3 mol / L 4-mercaptobenzoic acid solution (i.e., 4-MBA solution, prepared by dissolving 4-mercaptobenzoic acid powder in alcohol and then preparing it with ultrapure water) was diluted to prepare the concentrations of 1×10 -10 mol / L, 1×10 -9 mol / L, 1×10 -8 mol / L, 1×10 -7 mol / L, 1×10 -6 mol / L, 1×10 -5 mol / L, 1×10 -4 mol / L, 1×10 -3 mol / L, 1×10 -2 mol / L, 1×10 -1 mol / L thiram 4-MBA solution was used as the standard solution of thiram;

[0046] (2) Establishment of standard curve

[0047] (2-1) Pour the standard solution of melamine of a certain concentration prepared in step (1) into the test kit until the test kit is filled;

[0048] (2-2) Scan the QR code on the detection box to start the remote detection system;

[0049] (2-3) a computer triggers a semiconductor laser, and laser light emitted by the semiconductor laser is filtered by a first filter and then emitted into the detection box through a third bifurcated optical fiber, a first bifurcated optical fiber, and an input interface, thereby obtaining an enhanced Raman scattered light signal containing spectral information of melamine in the test kit. The enhanced Raman scattered light signal enters a second bifurcated optical fiber and a fourth bifurcated optical fiber through an output interface, and then enters a second filter. The second filter filters out background light and then enters a Raman spectrometer. The Raman spectrometer converts the optical signal into an electrical signal and transmits it to a computer. The computer processes the electrical signal data to obtain enhanced Raman scattering spectrum data of melamine.

[0050] (2-4) repeating steps (2-1) to (2-3) twice, summarizing the enhanced Raman scattering spectral data of melamine obtained from the three tests and taking an average value;

[0051] (2-5) repeating steps (2-1) to (2-4) to obtain an average value of enhanced Raman scattering spectral data of other standard solutions of melamine with different concentrations;

[0052] (2-6) According to the average value of the enhanced Raman scattering spectrum data obtained, the 699 cm -1 The relative peak intensity of the characteristic peak of melamine at 699 cm and the concentration data of melamine were fitted by the least square method to establish a 699 cm -1 The relationship between the relative peak intensity of the characteristic peak of melamine at Figure 4 shown);

[0053] (3) Repeat steps (1) to (2) to obtain 1164 cm -1 The relationship between the relative peak intensity of the characteristic peak of saccharin sodium and the concentration of saccharin sodium (such as Figure 5 shown), and 1377cm -1 The relationship between the relative peak intensity of the characteristic peak of thiram and the concentration of thiram (such as Figure 6 As shown), a standard solution prepared in step (1-3) with a concentration of 1×10 -3 The SERS spectrum of 4-MBA solution of 1 mol / L thiram is shown in Figure 2. Figure 8As shown in FIG. 1 , the SERS spectra when 4-MBA and thiram are present at the same time are plotted. All concentration relationship lines of melamine, sodium saccharin and thiram are summarized to establish a database.

[0054] (4) Dissolve 4-mercaptobenzoic acid powder in alcohol and prepare it with ultrapure water to a concentration of 10 -3 mol / L 4-mercaptobenzoic acid solution, repeat steps (2-1) to (2-3) three times, summarize the enhanced Raman scattering spectrum data of 4-mercaptobenzoic acid obtained by the three tests and take the average value to obtain 10 -3 mol / L 4-mercaptobenzoic acid solution (SERS spectrum of 4-MBA is shown in Figure 7 ), put it into the database established in step (3);

[0055] (5) When the user family needs to test whether milk contains melamine, whether white wine contains sodium saccharin, or whether there is residual thiram on the surface of vegetables, the milk, white wine or vegetable washing water to be tested is poured into the test kit. After filling the test kit, the QR code on the test box is scanned to start the remote detection system. Finally, the computer compares the data in the database based on the relative peak intensity in the enhanced Raman scattering spectrum obtained to determine the type and concentration of the tested substance and feedback the test results to the user family. If the tested solution contains melamine, the computer will pass the 699cm -1 The characteristic peak of melamine was determined by fitting, and the peak at 699 cm -1 The concentration of melamine is determined by the linear relationship between the relative peak intensity of the characteristic peak of melamine at 1164 cm and the concentration of melamine. -1 The characteristic peak of saccharin sodium was determined by fitting the 1164 cm -1 The concentration of saccharin sodium is determined by the linear relationship between the relative peak intensity of the characteristic peak of saccharin sodium at 1377 cm and the concentration of saccharin sodium. -1 The characteristic peak of thiram was determined by fitting, and the peak at 1377 cm was established. -1 The concentration of thiram was determined by the straight line relationship between the relative peak intensity of the characteristic peak of thiram and the concentration of thiram.

[0056] Before the above step (5) is carried out, the user family can first -3Fill the test kit with a 4-Mercaptobenzoic acid solution (100 mol / L). Scan the QR code on the test kit to activate the remote detection system. The computer compares the relative peak intensity of the enhanced Raman scattering spectrum with the database. After confirming that the test result is 4-mercaptobenzoic acid and its concentration, the test kit is washed with ultrapure water before proceeding to step (5). The purpose of this is to determine the entire system pathway before testing to ensure that the system can be used normally.

[0057] In Example 2 above, the present invention's method and features are illustrated solely by detecting melamine in milk, sodium saccharin in liquor, and thiram in vegetable washing water. This is intended to enable those skilled in the art to implement the invention according to its scope. However, the scope of the test objects is not limited to melamine, sodium saccharin, and thiram. In actual application, the present invention can be used to perform personalized tests based on the needs of different users. Therefore, all equivalent variations or modifications based on the principles and methods of the present invention are within the scope of protection of the present invention.

Claims

1. A remote detection system based on optical fiber surface enhanced Raman scattering, characterized in that: The invention comprises a detection box, a total optical fiber bundle, a first optical fiber beam splitter, a second optical fiber beam splitter, a first filter, a second filter, a semiconductor laser, a Raman spectrometer and a computer. The detection box is arranged in the user's home. The detection box comprises an input interface, an output interface, a QR code and a reagent kit. The QR code is pasted on the detection box, and the QR code is used for the user to scan the code to start the remote detection system. The reagent kit is arranged in the detection box. A section of optical fiber taper waist is arranged in the reagent kit. The optical fiber taper waist is made of multimode quartz optical fiber. The surface of the optical fiber taper waist is silanized. The surface of the silanized optical fiber taper waist is adsorbed with star-shaped gold nanoparticles. The gold nanoparticles are wrapped by silica. One end of the optical fiber taper waist is connected to the input interface via an optical fiber, and the other end of the optical fiber taper waist is connected to the output interface via an optical fiber. The first bifurcated optical fiber and the second bifurcated optical fiber are separated from the total optical fiber bundle via the first optical fiber beam splitter. The second bifurcated optical fiber is separated from the total optical fiber bundle via the second optical fiber The beam splitter branches out a third bifurcated optical fiber and a fourth bifurcated optical fiber. The output end of the semiconductor laser is connected to the input interface via the first filter, the third bifurcated optical fiber, and the first bifurcated optical fiber in sequence. The output interface is connected to the input end of the Raman spectrometer via the second bifurcated optical fiber, the fourth bifurcated optical fiber, and the second filter in sequence. The output end of the Raman spectrometer is connected to the input end of the computer. The trigger signal output end of the computer is connected to the input end of the semiconductor laser. The detection box is used to collect enhanced Raman scattered light signals of the substance to be tested contained in liquid food or food soaking liquid obtained by soaking non-liquid food in 4-mercaptobenzoic acid solution. The Raman spectrometer is used to receive the enhanced Raman scattered light signals, convert the optical signals into electrical signals, and transmit them to the computer. The computer is used to process the electrical signal data to obtain enhanced Raman scattering spectrum data and perform data comparison in a pre-established database to determine the type and concentration of the tested substance, and ultimately feedback the test results to the user's home.

2. A remote detection system based on optical fiber surface enhanced Raman scattering according to claim 1, characterized in that: The wavelength of the laser emitted from the output end of the semiconductor laser is 785nm, the power is 2.5-10mW, and the line width is 0.3nm.

3. The remote detection system based on optical fiber surface enhanced Raman scattering according to claim 1, characterized in that: The first bifurcated optical fiber, the second bifurcated optical fiber, the third bifurcated optical fiber and the fourth bifurcated optical fiber are all quartz optical fibers. The transmittance of the first optical fiber beam splitter and the second optical fiber beam splitter is greater than or equal to 95%, the splitting ratio is 50:50, and the splitting ratio deviation is ±8%.

4. The remote detection system based on optical fiber surface enhanced Raman scattering according to claim 1, characterized in that: The first filter is a 785nm bandpass filter, and the second filter is a 785nm high-pass filter.

5. The remote detection system based on optical fiber surface enhanced Raman scattering according to claim 1, characterized in that: The Raman spectrometer uses a grating with a line count of 800 / mm as a light-splitting element, the slit width of the system is 20 μm, and the signal-to-noise ratio is higher than 6500:

1.

6. A detection method implemented by a remote detection system based on optical fiber surface enhanced Raman scattering according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Preparation of standard solution Prepare standard solutions of the substance to be tested with different concentrations; (2) Establishment of standard curve (2-1) Pour the standard solution of one concentration prepared in step (1) into the reagent box until the reagent box is completely filled; (2-2) Scan the QR code on the detection box to start the remote detection system; (2-3) The computer triggers the semiconductor laser. The laser light emitted by the semiconductor laser is filtered by the first filter and then emitted into the detection box through the third bifurcated optical fiber, the first bifurcated optical fiber, and the input interface, thereby obtaining an enhanced Raman scattered light signal containing spectral information of the substance to be tested in the test kit. The enhanced Raman scattered light signal enters the second bifurcated optical fiber and the fourth bifurcated optical fiber through the output interface and then enters the second filter. The background light is filtered out by the second filter and then enters the Raman spectrometer. The Raman spectrometer converts the optical signal into an electrical signal and transmits it to the computer. The computer processes the electrical signal data to obtain enhanced Raman scattering spectrum data of the substance to be tested. (2-4) Repeat steps (2-1) to (2-3) twice, summarizing the enhanced Raman scattering spectral data of the test substance obtained from the three tests and taking an average value; (2-5) Repeat steps (2-1) to (2-4) to obtain the average value of enhanced Raman scattering spectrum data of other test substances with different concentrations; (2-6) establishing a linear relationship between the relative peak intensity of the characteristic peak of the substance to be tested and the concentration of the substance to be tested using a least squares fitting method based on the relative peak intensity of the characteristic peak of the substance to be tested and the concentration data of the substance to be tested in the average value data of the enhanced Raman scattering spectrum data obtained; (3) Repeat steps (1) to (2) to obtain straight lines of relationship between relative peak intensity and concentration of other different types of test substances, summarize all concentration relationship straight lines, and establish a database; (4) Dissolve 4-mercaptobenzoic acid powder in alcohol and prepare it with ultrapure water to a concentration of 10 -3 mol / L 4-mercaptobenzoic acid solution, repeat steps (2-1) to (2-3) three times, summarize the enhanced Raman scattering spectrum data of 4-mercaptobenzoic acid obtained by the three tests and take the average value to obtain 10 -3 The enhanced Raman scattering spectrum data of the mol / L 4-mercaptobenzoic acid solution is placed into the database established in step (3); (5) The user's family will test the liquid food or the liquid food with a concentration of 10 -3 The food soaking liquid obtained by soaking non-liquid food in 10 mol / L 4-mercaptobenzoic acid solution is poured into the test kit. After filling the test kit, scan the QR code on the test box to start the remote detection system. Finally, the computer compares the data in the database based on the relative peak intensity in the enhanced Raman scattering spectrum obtained, determines the type and concentration of the measured substance, and feeds back the test results to the user's home.

7. The detection method according to claim 6, characterized in that Before proceeding to step (5), the user's family first -3 The test kit is filled with a 4-mercaptobenzoic acid solution of 1 mol / L. The QR code on the test kit is scanned to start the remote detection system. The computer compares the data in the database based on the relative peak intensity in the enhanced Raman scattering spectrum obtained. After determining that the test result is 4-mercaptobenzoic acid and its concentration, the test kit is first washed with ultrapure water, and then step (5) is performed.

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