A device and method for detecting aflatoxins in two modalities

Abstract

The application discloses a device and method for detecting aflatoxin in a bimodal mode; the device comprises a fluorescence signal acquisition system, a SERS signal acquisition system, a signal processing system and a lifting system; the fluorescence signal acquisition system, the SERS signal acquisition system and the signal processing system are assembled together by a fixing device, the sample is lifted to a suitable position through the lifting system, the fluorescence signal and the SERS signal are simultaneously acquired, and the signal system outputs the signals acquired by the fluorescence signal acquisition system and the SERS signal acquisition system to a terminal after processing. The application adopts a double-signal detection method, flexibly detects under various experimental conditions by using two kinds of alternative instruments, and combines the two signals to verify and supplement each other, thereby improving the detection performance. The application realizes the simultaneous acquisition of SERS-fluorescence signals in a cuvette by collecting signals in different regions, is more convenient to use, reduces the technical application cost, and makes the application more extensive.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nanomaterials and food science, and particularly relates to a device and method for detecting aflatoxin in a dual mode. BACKGROUND

[0002] Aflatoxin is a kind of mycotoxin with the widest distribution, the strongest toxicity and the greatest harm. It is mainly distributed in cereals, nuts and their processed products, and is metabolized by Aspergillus flavus and parasitic Aspergillus under humid conditions. Aflatoxin has very good thermal stability and is difficult to destroy. It is not easy to decompose by using cooking methods and conventional thermal processing methods. The contamination of aflatoxin in grain and its processed products can cause liver cancer and esophageal cancer.

[0003] At present, the methods for detecting aflatoxin include enzyme-linked immunosorbent assay, high performance liquid chromatography and thin layer chromatography, which are based on single signal detection methods and are easily disturbed by coexisting substances, various instruments and non-standard analysis procedures.

[0004] Surface enhanced Raman spectroscopy (SERS) is an ultra-sensitive and rapid detection technology, which has a unique molecular structure fingerprint and can significantly amplify the Raman signal, and even realize the ultra-sensitive detection of single molecules. However, due to the uneven dispersion of the substrate, the reproducibility and stability are relatively poor sometimes. Fluorescence is an electronic transition phenomenon produced by the internal molecules of a substance. After adding a target analyte to the fluorescent substance, fluorescence quenching or enhancement can occur. According to the degree of fluorescence quenching or enhancement, quantitative analysis of the analyte can be realized. The detection limit is low, the analysis is real-time and rapid, the detection range is large, and the cost is low. The advantages and disadvantages of the two are complementary. Therefore, the combination of SERS and fluorescence can improve the reliability and accuracy of detection, and broaden the detection range, and better verify the detection results of each other. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings and deficiencies of the prior art, and to provide a device and method for detecting aflatoxin in a dual mode. The present application uses dual signal detection, which can be flexibly detected under various experimental conditions by using two alternative instruments, and the two signals are combined to verify and supplement each other, thereby improving the detection performance.

[0006] The present application is realized by the following technical solutions:

[0007] A device for detecting aflatoxin in a dual mode, comprising a fluorescence signal acquisition system 1, a SERS signal acquisition system 2, a signal processing system 3, a lifting system 4 and a fixing device 5.

[0008] The fluorescence signal acquisition system 1 and the SERS signal acquisition system 2 are connected with a signal processing system 3;

[0009] The fluorescence signal acquisition system 1 comprises a fluorescence light source 1-1; the fluorescence light source 1-1 is fixed on a detection table through a cuvette fixing part 1-2, and after the sample is measured, signal output is performed through another end USB communication line 1-3;

[0010] The SERS signal acquisition system 2 comprises a SERS laser 2-1 and a SERS detection device 2-2, and the front end of the SERS detection device 2-2 is an electromagnetic eddy current SERS detection probe 2-3; the SERS laser 2-1 emits laser, and is connected with the SERS detection device 2-2 through a USB communication line;

[0011] The signal processing system 3 comprises a fluorescence spectrometer 3-1, a computer 3-2 and a SERS spectrometer 3-3; the fluorescence spectrometer 3-1 processes the signal collected from the fluorescence signal acquisition system 1, and then inputs the signal into the computer 3-2 for signal output; similarly, the SERS spectrometer 3-3 processes the signal from the SERS signal acquisition system 2, and then inputs the signal into the computer 3-2 for signal output.

[0012] The electromagnetic eddy current SERS detection probe 2-3 comprises an electromagnetic device;

[0013] The electromagnetic device comprises a first electromagnet 2-3-1, a second electromagnet 2-3-2, a third electromagnet 2-3-3 and a fourth electromagnet 2-3-4 which are equally distributed in the inner periphery of an electromagnet fixing cylinder 2-4;

[0014] The first electromagnet 2-3-1, the second electromagnet 2-3-2, the third electromagnet 2-3-3 and the fourth electromagnet 2-3-4 all have independent power control switches;

[0015] The control system controls the on-off of each power control switch to control the current direction and current size in the first electromagnet 2-3-1, the second electromagnet 2-3-2, the third electromagnet 2-3-3 and the fourth electromagnet 2-3-4;

[0016] The control system also controls the on-off of each power control switch to control the sequence of the on-off of the first electromagnet 2-3-1, the second electromagnet 2-3-2, the third electromagnet 2-3-3 and the fourth electromagnet 2-3-4.

[0017] After the first electromagnet 2-3-1, the second electromagnet 2-3-2, the third electromagnet 2-3-3 and the fourth electromagnet 2-3-4 are connected with power, they respond in the following sequence:

[0018] S1: the first electromagnet 2-3-1 is on, the second electromagnet 2-3-2 is on, the third electromagnet 2-3-3 is on, and the fourth electromagnet 2-3-4 is on;

[0019] S2: the first electromagnet 2-3-1 is on, the second electromagnet 2-3-2 is off, the third electromagnet 2-3-3 is off, and the fourth electromagnet 2-3-4 is off;

[0020] S3: the first electromagnet 2-3-1 is off, the second electromagnet 2-3-2 is on, the third electromagnet 2-3-3 is on, and the fourth electromagnet 2-3-4 is off;

[0021] S4: the first electromagnet 2-3-1 is off, the second electromagnet 2-3-2 is off, the third electromagnet 2-3-3 is on, and the fourth electromagnet 2-3-4 is on;

[0022] S5: the first electromagnet 2-3-1 is on, the second electromagnet 2-3-2 is off, the third electromagnet 2-3-3 is off, and the fourth electromagnet 2-3-4 is on;

[0023] According to the sequence of S1-S5, the magnetic force of each electromagnet changes due to the change of current, and the magnetic force changes in the order from large to small, finally making the magnetic particles in the cuvette uniformly swing;

[0024] In S1-S5, on represents starting, off represents closing, and on- represents weakening the current.

[0025] The lifting system 4 comprises a lifting screw 4-1 and a cuvette fixing plate 4-2; the cuvette fixing plate 4-2 is threadedly matched with the lifting screw 4-1, the height of the cuvette fixing plate 4-2 is modified by rotating the lifting screw 4-1, and the cuvette above is lifted.

[0026] The fixing device 5 comprises a bottom plate 5-1, a fixing piece 5-2, and a clamping device 5-3; the clamping device 5-3 is fixed on the bottom plate 5-1 through the fixing piece 5-2;

[0027] The lifting screw 4-1 is fixed on the bottom plate 5-1; the clamping device 5-3 is used for clamping and fixing the electromagnetic vortex SERS detection probe 2-3.

[0028] A method for detecting aflatoxin in a dual-mode manner: first, place the sample cuvette to be detected on the cuvette fixing plate 4-2, and then lift it to a suitable position through the lifting screw 4-1; in order to facilitate detection, the cuvette is installed at a proper position through the cuvette fixing plate 4-2 and the cuvette fixing piece 1-2;

[0029] The fluorescence signal acquisition system 1 and the SERS signal acquisition system 2 are installed on the upper and lower sides of the detection table through the fixing device 5, and the fluorescence signal acquisition system 1 is located at more than 2 / 3 of the cuvette, and the SERS signal acquisition system 2 is located at less than 1 / 3, so that the fluorescence detection on the upper side and the SERS signal measurement on the lower side can be realized at the same time; the fluorescence signal acquisition system 1 and the SERS spectrum acquisition system 2 are opened at the same time; the bimodal detection of aflatoxin is started, the fluorescence signal detection is carried out through the fluorescence light source 1-1 to emit light, the light transmits through the cuvette, the fluorescence signal is received at the other end, and after the pre-processing of the fluorescence spectrometer 3-1 in the signal processing system 3, the signal is input to the computer 3-2, so that the fluorescence signal acquisition and output are completed;

[0030] At the same time, the electromagnetic eddy current SERS detection probe 2-3 is controlled by the controller and circulates in sequence according to steps S1-S5, due to the current change, the magnetic force of each electromagnet changes, the magnetic force changes in sequence from large to small, and finally the magnetic particles in the cuvette are uniformly shaken, so that the signal detected at this time is more uniform and more representative; the SERS laser 2-1 emits a fixed wavelength laser, the SERS detection device 2-2 detects the sample, the SERS spectrometer 3-3 pre-processes the information fed back by the SERS probe 2-3, and the pre-processed signal is transmitted to the computer 3-2; the fluorescence signal acquisition system 1 and the SERS signal acquisition system 2 acquire information, and the signal processing system 3 processes the information for final processing and output.

[0031] For data processing of the fluorescence signal, the standard curve of the target substance, that is, the linear equation between the logarithmic concentration of aflatoxin and the fluorescence intensity, is calculated in advance, and the measured fluorescence intensity is brought into the linear equation to obtain the concentration of aflatoxin. Similarly, when the device is used to detect the SERS spectrum of the standard solution of aflatoxin, the linear regression equation of the logarithmic concentration of the standard solution of aflatoxin and the SERS intensity of the characteristic peak is obtained, and the SERS intensity of the characteristic peak during the determination is substituted into the equation to obtain the concentration of aflatoxin.

[0032] Compared with the prior art, the present application has the following advantages and effects:

[0033] The present application adopts a double-signal detection method, which can be flexibly detected under various experimental conditions by using two alternative instruments, and the two signals are combined to verify and supplement each other, thereby improving the detection performance. The present application provides a method for detecting aflatoxin by using double signals, which realizes the simultaneous acquisition of SERS-fluorescence signals in one cuvette through regional acquisition, is more convenient to use, reduces the cost of technical application, and makes the application more widely used. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1The overall schematic diagram of the device for detecting aflatoxin in the application.

[0035] Figure 2 The front view of the device for detecting aflatoxin in the application.

[0036] Figure 3 The enlarged view of the electromagnetic vortex SERS detection probe in the application.

[0037] Figure 4 The top view of the electromagnetic vortex SERS detection probe in the application.

[0038] Figure 5 The enlarged view of the iron part of the electromagnetic vortex SERS detection probe in the application (side view).

[0039] Figure 6 The SERS spectrum of the device for detecting aflatoxin in the application when detecting AFB1 of different concentrations and the linear regression curve of the SERS intensity at 1467 cm -1 and the logarithmic concentration of AFB1.

[0040] Figure 7 The fluorescence spectrum of the device for detecting aflatoxin in the application when detecting AFB1 of different concentrations and the linear regression curve of the fluorescence intensity at 668 nm and the logarithmic concentration of AFB1.

[0041] Figure 8 The coefficient of variation (CV) obtained when AFB1 in peanut (A), walnut (B) and almond (C) samples was determined by independent SERS, independent fluorescence, the combination of fluorescence and SERS determination data (SERS+FL). DETAILED DESCRIPTION

[0042] The application will be further described in detail below in combination with examples and drawings, but the implementation method of the application is not limited thereto.

[0043] The specific conditions not mentioned in the embodiments of the application are carried out according to conventional conditions or the conditions recommended by the manufacturer. The raw materials, reagents and the like used without mentioning the manufacturer are all conventional products that can be purchased on the market.

[0044] (1) Synthesis of MNP@Ag-PEI

[0045] Firstly, MNP (ZnFe2O4) was prepared by EG / EDG double hot solvent method; then a layer of positive polyethyleneimine (PEI) was adsorbed on the surface (negative) of MNP, and then a layer of negative AuNPs was connected on the surface of MNP@PEI; with AuNPs as seed site, a layer of silver shell was modified on the surface of MNP@PEI by silver-ammonia reaction, forming MNP@Ag, and the thickness and shape of the silver shell were controlled by controlling the amount of AgNO3 added. Then different volumes (50, 100, 200, 300 and 400 μL) of PEI (5 mg / mL) were mixed with the prepared MNP@Ag (400 μL), and ultrasonic was performed for 30 minutes to form MNP@Ag-PEI microspheres. After washing with ultrapure water for five times, the obtained MNP@Ag-PEI microspheres were finally diluted with ultrapure water to 400 μL.

[0046] (2) Detection of actual samples

[0047] For the detection of AFB1in real samples, three uncontaminated nuts (peanuts, walnuts and almonds) were first selected as pretreated real samples. Then, the three samples were ground into powder, respectively, and weighed to 5 g, respectively. Next, 100 μL of AFB1solution (100 μg / mL) was added to the three powders (5 g) and left for 30 minutes, respectively, and the powder of each nut was dissolved in a mixture of methanol and ultrapure water (Vmethanol:Vwater = 4:1, total volume 9.9 mL), respectively, and then ultrasonicated for 30 minutes to assist extraction, and after centrifugation at 12000 rpm for 30 minutes, 15 mg of GBC and 400 mg of PSA were added to 3 mL of supernatant, respectively, and then shaken (1200 rpm) for 10 minutes to remove excess pigments, organic acids and fats. After centrifugation at 8000 rpm for 5 minutes, the supernatant was filtered using a 0.22 μm micro membrane sterile syringe filter. The same volume of apt-cy5 (10 μM) was mixed with the filtered supernatant, and then Tris-HCl (pH 7.4) was added to make the total volume 215 μL. After incubation for the same time, the solution was transferred to a cuvette, which was placed on the cuvette fixing plate 4-2, and was raised to the appropriate position by the lifting support rod 4-1. At the same time, the fluorescence signal acquisition system 1 and the SERS spectrum acquisition system 2 were turned on. The fluorescence spectrum was measured at an excitation wavelength of 590 nm using a fluorescence spectrophotometer, and the SERS spectrum was measured at a laser of 785 nm using a laser confocal Raman microscope system. After the fluorescence light source 1-1 emitted light, the light passed through the cuvette and was received at the other end, and after processing by the fluorescence spectrometer 3-1 in the signal processing system 3, the processed signal was transmitted to the computer 3-2, and the fluorescence signal acquisition and output were completed. On the other hand, the electromagnetic eddy current SERS detection probe 2-3, under the condition of power supply, realized the uniform rotation of the magnetic particles around the SERS probe in the cuvette through the design of the electromagnet program, so that the signal detected at this time was more uniform and more representative. After the SERS laser 2-1 emitted a fixed wavelength laser, the SERS detection device 2-2 and the SERS probe 2-3 detected the sample, and then the signal was pre-processed by the SERS spectrometer 3-3 in the signal processing system 3 and transmitted to the computer 3-2, and the SERS spectrum acquisition and output were completed. Finally, the output and summary of the double signals were completed on the computer 3-2.

[0048] Based on the optimized detection conditions, the sensitivity of the dual signal aptamer sensor was determined by introducing a series of AFB1standard solutions with different concentrations.

[0049] The common fluorescent dye cy5 can be used as a fluorophore to display fluorescence signal and as a Raman beacon to display SERS signal. The specific binding between AFB1 and cy5-modified aptamer (apt-cy5) can regulate SERS and fluorescence intensity and show completely opposite signal changes. Therefore, the linear relationship between AFB1 concentration can be obtained according to the decrease of SERS intensity and the increase of fluorescence intensity, and thus a SERS-fluorescence dual-signal aptamer sensor is successfully constructed to quantitatively detect AFB1.

[0050] Figure 6 (A) is the SERS spectrum of the dual-signal sensor for detecting AFB1 standard solution. As can be seen from the figure, the SERS intensity of cy5 gradually decreases with the increase of AFB1 concentration. Figure 6 (B) is the linear relationship between the logarithmic concentration of AFB1 standard solution and the SERS intensity at 1467 cm -1 -1. The linear regression equation is y=-1038.15x+3416.54, the correlation coefficient R 2 is 0.9980, and the linear range is 0.001-1000 ng / mL. On this basis, the LOD and LOQ are calculated as 0.45 pg / mL and 1.499 pg / mL, respectively.

[0051] The fluorescence peak of cy5 is at 668 nm, so the fluorescence intensity at 668 nm is selected for linear regression analysis. Figure 7 (A) is the fluorescence spectrum of the dual-signal sensor for detecting AFB1 standard solution. As can be seen from the figure, the fluorescence intensity of cy5 in the supernatant gradually increases with the increase of AFB1 concentration. Figure 7 (B) is the linear relationship between the logarithmic concentration of AFB1 standard solution and the fluorescence intensity at 668 nm. The calculated linear regression equation is y=1083.83x+1128.24, the correlation coefficient R 2 =0.9904, and it is linearly proportional to the logarithmic concentration of AFB1 standard solution in the linear range of 0.2-2×10 4 ng / mL. The calculated LOD is 0.135 ng / mL, and the LOQ is 0.450 ng / mL.

[0052] Finally, the feasibility of the sensor in real sample determination was explored by recovery experiments with spiked AFB1 in nut samples. The determination results of real samples are shown in Table 1. Both SERS and fluorescence methods showed satisfactory recoveries, with recoveries of 95.2%-108.6% for SERS and 94.7%-109.7% for fluorescence, and RSD values of both methods not more than 9.7%, confirming the accuracy of the dual-signal aptasensor. In addition, the coefficient of variation (CV) of the dual-signal aptasensor in detecting real samples was calculated and compared with the CV value obtained by combining the measurement results of SERS and fluorescence data (SERS + FL) to further confirm the advantages of the dual-signal aptasensor in use. As shown in Table 1 and Figs. (A), (B), the CV values obtained by combining the two measurement data (SERS + FL) are mostly between the independent fluorescence and independent SERS methods, thus effectively proving that the dual-signal aptasensor can verify the detection results of SERS and fluorescence methods, thereby better improving the detection accuracy and proving the advantages of the dual-signal aptasensor. Figure 8 (A), (B), the CV values obtained by combining the two measurement data (SERS + FL) are mostly between the independent fluorescence and independent SERS methods, thus effectively proving that the dual-signal aptasensor can verify the detection results of SERS and fluorescence methods, thereby better improving the detection accuracy and proving the advantages of the dual-signal aptasensor.

[0053] (3) Statistical analysis

[0054] The measurement conditions for all SERS spectra were: 785 nm excitation laser source, power of 100 mV, collection time of 10 s, and recording five times. Similarly, all fluorescence spectra were collected three times under the following conditions: excitation wavelength of 590 nm, scanning range of 620-720 nm, and scanning speed of 600 nm / min. The average value ± its standard deviation was used as the SERS and fluorescence intensity. At the same time, all other experimental measurements were made in triplicate, and the final results were expressed as the average value ± standard deviation. The particle size distribution of MNP, AuNPs, MNP@AuNPs, and MNP@Ag was performed by Nano Measurer 1.2 software (Chemistry Department, Fudan University, China). All data were analyzed and processed by Excel 2016 and Origin 2019b software (OriginLab Co., MA, USA).

[0055] Finally, the limit of detection (LOD) and the limit of quantification (LOQ) were calculated by the following formula:

[0056] Y LOD = 3S0 + Y0 (1);

[0057] LOQ = 3.33 LOD (2);

[0058] wherein S0 represents the standard deviation of SERS or fluorescence intensity in a blank sample, and Y0 represents the average SERS or fluorescence intensity of the blank sample.

[0059] Table 1: Detection of spiked AFB1 in nut samples (peanut, walnut and almond) using the established dual signal aptasensor and traditional ELISA method

[0060]

[0061] As described above, the application can be better implemented.

[0062] The embodiments of the present application are not limited to the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement modes and shall be included in the protection scope of the present application.

Claims

1. A device for the detection of aflatoxins in two modalities, characterized in that, It comprises a fluorescence signal acquisition system (1), a SERS signal acquisition system (2), a signal processing system (3), a lifting system (4) and a fixing device (5); The fluorescence signal acquisition system (1) and the SERS signal acquisition system (2) are connected with the signal processing system (3); The fluorescence signal acquisition system (1) comprises a fluorescence light source (1-1); the fluorescence light source (1-1) is fixed on the detection table through a cuvette fixing piece (1-2), and signal output is performed through another end communication line (1-3) after the sample is determined; The SERS signal acquisition system (2) comprises a SERS laser (2-1) and a SERS detection device (2-2), and the front end of the SERS detection device (2-2) is an electromagnetic eddy current SERS detection probe (2-3); the SERS laser (2-1) emits laser, and is connected with the SERS detection device (2-2) through a USB communication line; The signal processing system (3) comprises a fluorescence spectrometer (3-1), a computer (3-2) and a SERS spectrometer (3-3); the fluorescence spectrometer (3-1) processes the signal collected from the fluorescence signal acquisition system (1), and then inputs the signal into the computer (3-2) for signal output; similarly, the SERS spectrometer (3-3) processes the signal from the SERS signal acquisition system (2), and then inputs the signal into the computer (3-2) for signal output; The electromagnetic eddy current SERS detection probe (2-3) comprises an electromagnetic device; The electromagnetic device comprises a first electromagnet (2-3-1), a second electromagnet (2-3-2), a third electromagnet (2-3-3) and a fourth electromagnet (2-3-4) which are evenly distributed in the inner periphery of an electromagnet fixing cylinder (2-4); The first electromagnet (2-3-1), the second electromagnet (2-3-2), the third electromagnet (2-3-3) and the fourth electromagnet (2-3-4) all have independent power control switches; The on-off of each power control switch is controlled by a control system, so as to control the current direction and current size in the first electromagnet (2-3-1), the second electromagnet (2-3-2), the third electromagnet (2-3-3) and the fourth electromagnet (2-3-4); The control system also controls the on-off of each power control switch, so as to control the sequence of the first electromagnet (2-3-1), the second electromagnet (2-3-2), the third electromagnet (2-3-3) and the fourth electromagnet (2-3-4).

2. The device for the detection of aflatoxins in two modalities according to claim 1, characterized by the fact that: After the first electromagnet (2-3-1), the second electromagnet (2-3-2), the third electromagnet (2-3-3) and the fourth electromagnet (2-3-4) are connected with the power supply, they are cyclically responded in the following sequence: S1: the first electromagnet (2-3-1) is on, the second electromagnet (2-3-2) is on, the third electromagnet (2-3-3) is on, and the fourth electromagnet (2-3-4) is on; S2: the first electromagnet (2-3-1) is on, the second electromagnet (2-3-2) is off, the third electromagnet (2-3-3) is off, and the fourth electromagnet (2-3-4) is off; S3: the first electromagnet (2-3-1) off, the second electromagnet (2-3-2) on, the third electromagnet (2-3-3) on-, the fourth electromagnet (2-3-4) off; S4: the first electromagnet (2-3-1) off, the second electromagnet (2-3-2) off, the third electromagnet 2-3 on, the fourth electromagnet (2-3-4) on-; S5: the first electromagnet (2-3-1) on-, the second electromagnet (2-3-2) off, the third electromagnet (2-3-3) off, the fourth electromagnet (2-3-4) on; According to the sequence of S1-S5, the magnetic force of each electromagnet changes due to the change of current, and the magnetic force changes in the order from large to small, finally making the magnetic particles in the cuvette uniformly swing; In S1-S5, on represents starting, off represents closing, and on- represents weakening current.

3. The device for detecting aflatoxins in two modes of claim 1, characterized in that: The lifting system (4) comprises a lifting screw rod (4-1) and a cuvette fixing plate (4-2); the cuvette fixing plate (4-2) is in threaded cooperation with the lifting screw rod (4-1), the height of the cuvette fixing plate (4-2) is modified by rotating the lifting screw rod (4-1), and the cuvette above is driven to lift.

4. The device for detecting aflatoxins in two modes of claim 3, characterized by: The fixing device (5) comprises a bottom plate (5-1), a fixing piece (5-2) and a clamping sleeve device (5-3); the clamping sleeve device (5-3) is fixed on the bottom plate (5-1) through the fixing piece (5-2); The lifting screw rod (4-1) is fixed on the bottom plate (5-1); the clamping sleeve device (5-3) is used for clamping and fixing the electromagnetic eddy current SERS detection probe (2-3).

5. The device for detecting aflatoxins in two modes of claim 3, characterized by: The communication line (1-3) is a USB transmission line.

6. A method of detecting aflatoxins in a dual mode, characterized by The device is realized by any one of claims 1-4, and specifically as follows: First, place the sample cuvette to be tested on the cuvette fixing plate (4-2), and lift it to the appropriate position by the lifting screw rod (4-1); in order to facilitate detection, the cuvette is installed in the appropriate position through the cuvette fixing plate (4-2) and the cuvette fixing piece (1-2); The fluorescence signal acquisition system (1) and the SERS signal acquisition system (2) are installed on the upper and lower sides of the detection table through the fixing device (5), and the fluorescence signal acquisition system (1) is located at more than 2 / 3 of the cuvette, and the SERS signal acquisition system (2) is located at less than 1 / 3, which can simultaneously realize the fluorescence detection above and the SERS signal measurement below; turn on the fluorescence signal acquisition system (1) and the SERS spectrum acquisition system (2) at the same time; start the bimodal detection of aflatoxin, the fluorescence signal is detected after the fluorescence light source (1-1) emits light, the light transmits through the cuvette, and the received fluorescence signal is preprocessed by the fluorescence spectrometer (3-1) in the signal processing system (3) and then input into the computer (3-2), completing the collection and output of the fluorescence signal; At the same time, the electromagnetic eddy current SERS detection probe (2-3) is under the control of the controller and is in a continuous cycle according to the sequence of steps S1-S5. Due to the change of current, the magnetic force of each electromagnet changes, and the magnetic force changes in the order from large to small, finally making the magnetic particles in the cuvette swing uniformly, so that the signal detected at this time is more uniform. The SERS laser (2-1) emits a fixed wavelength laser, and after the SERS detection device (2-2) detects the sample, the SERS spectrometer (3-3) pre-processes the information fed back by the SERS probe (2-3) and transmits the pre-processed signal to the computer (3-2); the fluorescence signal acquisition system (1) and the SERS signal acquisition system (2) collect information, which is processed by the signal processing system (3) for final processing and output.

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