Raman spectrum-based device and method for detecting inferior oil doped in edible oil

Abstract

The invention relates to the technical field of optical detection, in particular to a device and method for detecting poor-quality oil doped in edible oil based on Raman spectrum.The device comprises a Raman spectrometer body, the Raman spectrometer body comprises a shell, a mounting table is arranged at the front end of the shell, and a Raman detection opening is fixedly formed in the mounting table; the outer end of the mounting table is rotationally connected with a baffle plate; a shielding plate is rotatably mounted at the upper end of a mounting table, the shielding plate is upwards rotated to be opened during use, detection operation can be performed after a Raman detection port is exposed, the shielding plate is closed to protect the Raman detection port when the device is not used, a display screen is rotated by 90 degrees when the device is not used, and then the display screen slides into a mounting box along a sliding rail, so that the detection operation is completed. And the cover plate covers the display screen to store and protect the display screen, so that the size of the device is reduced, and the device is convenient to carry.

Description

Technical Field

[0001] The invention relates to the technical field of optical detection, and in particular to a device and method for detecting edible oil adulterated with inferior oil based on Raman spectroscopy. Background Art

[0002] The quality assessment of edible oil involves multiple parameters, such as acid value, peroxide value, fatty acid (oleic acid, erucic acid, etc.) composition, solvent residue, benzo(a)pyrene content, etc. The measurement of these parameters requires different detection methods and equipment, which increases the complexity and cost of detection. The current standard detection methods often have problems such as time-consuming, high cost, use of harmful organic solvents, generation of harmful waste, and complex operation. This not only increases the difficulty of detection, but also limits the efficiency and popularity of detection.

[0003] As an emerging food safety testing method, Raman spectroscopy technology has shown significant advantages in edible oil testing. Conventional Raman spectroscopy detection does not require complex pretreatment of samples, and usually does not damage samples during the detection process, achieving non-destructive testing, which reduces the requirements for samples and improves the convenience of detection. Raman spectroscopy is performed on rapeseed oil samples, and modeling and analysis are performed based on physical and chemical analysis values. In this way, multiple quality parameters of edible oil (such as acid value, peroxide value, etc.) can be detected, and the concentration of the substance to be detected can also be analyzed by spectral intensity. This makes Raman spectroscopy have a wider application prospect in edible oil detection, but the existing Raman spectroscopy is large in size and inconvenient to carry, and important components cannot be protected when not in use. Summary of the invention

[0004] The purpose of the present invention is to provide a device and method for detecting edible oil adulteration based on Raman spectroscopy to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned object, the present invention provides the following technical solution: a device for detecting inferior oil adulteration in edible oil based on Raman spectroscopy, comprising: a Raman spectrometer body, the Raman spectrometer body comprising a shell, a mounting platform is provided at the front end of the shell, a Raman detection port is fixedly installed on the mounting platform, and a shielding plate is rotatably connected to the outer end of the mounting platform;

[0006] An installation box is fixedly installed on the upper side of the rear end of the shell, and the upper end of the installation box is rotatably connected to a cover plate through a hinge. A fixing plate is fixedly installed on the rear end side wall of the installation box, and a slide rail is fixedly installed on the front end of the fixing plate. The lower end of the rail is located in the installation box, and a display screen is slidably connected to the rail through a sliding component. The display screen can be stored in the installation box.

[0007] Preferably, the slide rail is concave, a fixing groove is provided on the inner wall of the upper end of the slide rail, and a channel is provided on the upper end of the fixing groove.

[0008] Preferably, the lower end of the installation box is connected to the inner end of the shell, and the width of the installation box is greater than the width of the display screen.

[0009] Preferably, the sliding component comprises a fixing sleeve fixedly mounted on the rear end side wall of the display screen, a damping bearing is fixedly mounted in the fixing sleeve, and a round rod is fixedly sleeved on the inner wall of the damping bearing.

[0010] Preferably, the outer end of the round rod extends out of the damping bearing and is fixedly mounted with a slide plate, a limit plate is fixedly mounted on the outer wall of the round rod, and the outer wall of the slide plate is slidably connected to the inner wall of the slide rail.

[0011] Preferably, the slide plate can be inserted into the fixing groove, and when the lower end of the slide plate contacts the inner wall of the bottom end of the fixing groove, the round rod is located in the channel, and the limit plate contacts the outer end side wall of the slide rail.

[0012] A method for detecting edible oil adulteration with inferior oil based on Raman spectroscopy specifically comprises the following steps:

[0013] S1. Sample preparation

[0014] Select 40 parts of different types of rapeseed oil, soybean oil, enhancement reagent (A, nanogold), solvent No. 6 (standard solution concentration 10 mg / mL ± 0.5, N, N-dimethylacetamide as solvent), aflatoxin B1 standard solution, benzo(a)pyrene solution in methanol standard substance, n-hexane, cyclohexane solution, acetonitrile;

[0015] S2. Doping measurement

[0016] 1) Use a 20 ml vial to mix a certain gradient of soybean oil into rapeseed oil and mix well;

[0017] 2) Use a cuvette with a 10m optical path, set the integration power to 300mW, the integration time to 12000ms, collect three times and take the average value to collect the doped Raman spectrum;

[0018] 3) Import the collected spectral data into Aopu Tiancheng modeling software for modeling, and import the built model into Raman software for sample testing and verification;

[0019] S3. Quality index measurement

[0020] 1) The rapeseed oil sample was loaded into a cuvette with a 10 ml optical path, the integration power was set to 300 mW, the integration time was set to 12000 ms, and the average value was obtained three times to collect the Raman spectrum of the rapeseed oil;

[0021] 2) Import the collected spectral data into Aopu Tiancheng modeling software for modeling, and import the built model into Raman software for sample testing and verification;

[0022] 3) Directly test the No. 6 solvent standard solution and test the spectra of n-hexane and cyclohexane;

[0023] S4. Safety index measurement

[0024] Take 1 μl of aflatoxin B1 (GB 2761-2011 requires a limit of 10 μg / Kg) or benzo(a)pyrene sample (GB2762-2022 requires a limit of 10 μg / Kg) into 1 ml of added reagent (SERS), set the laser power to 300 mW, the integration time to 12000 ms, collect Raman spectra, find its characteristic peaks, and make a detection or non-detection judgment.

[0025] Preferably, the rapeseed oil mixed with soybean oil in S1 is modeled and analyzed using multiple linear regression, and the R square of the modeling is 0.97, which shows a strong correlation.

[0026] Preferably, the ratio of soybean oil mixed in rapeseed oil in S1 is 7.45%, 12.36%, 17.86% and 21.43% for verification, samples are collected and modeling is performed, and the R2 of oleic acid is 0.82, the R2 of erucic acid is 0.81, the linear correlation coefficient is good, and the root mean square errors are 5.6 and 3.63 respectively.

[0027] Preferably, the acid value and peroxide value are modeled and analyzed, and the R 2 The peroxide value is 0.93, and the R 2 The root mean square errors are 0.12 and 0.012 respectively, which can identify the 1 / 10,000 benzo(a)pyrene standard solution. The signal of 2ppm aflatoxin B1 is the solvent, and there is no significant signal using Raman enhancement reagent.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The shielding plate is installed by rotating it on the upper end of the mounting platform. When in use, the shielding plate is rotated upward to open it, exposing the Raman detection port for detection operation. When not in use, the shielding plate is closed to protect the Raman detection port. When the device is not in use, the display screen is rotated ninety degrees, and then slid into the mounting box along the slide rail, and the cover plate is closed to store and protect the display screen, thereby reducing the size of the device and facilitating carrying. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a front schematic diagram of the overall structure of the present invention;

[0031] Figure 2 It is a top view of the overall structure of the present invention;

[0032] Figure 3It is a side schematic diagram of the overall structure of the present invention;

[0033] Figure 4 It is a cross-sectional schematic diagram of the slide rail of the present invention;

[0034] Figure 5 This is a schematic diagram of the slide rail and the round rod of the present invention;

[0035] Figure 6 is the Raman spectrum of the edible oil of the present invention;

[0036] Figure 7 This is the Raman spectrum of the sixth solvent of the present invention;

[0037] Figure 8 This is the Raman spectrum of 1 / 10,000 benzo(a)pyrene (methanol as solvent) of the present invention;

[0038] Fig. 9 This is the Raman spectrum of 2ppm aflatoxin (acetonitrile as solvent) of the present invention

[0039] Fig.10 This is the Raman spectrum of rapeseed oil doped with soybean oil of the present invention;

[0040] Fig.11 This is a diagram of the oleic acid modeling results of the present invention;

[0041] Fig.12 This is a diagram of the modeling results of erucic acid of the present invention;

[0042] Fig.13 This is the detection diagram of solvent No. 6 of the present invention;

[0043] Fig.14 This is the Raman spectrum of 1 / 10,000 benzo(a)pyrene (methanol as solvent) of the present invention;

[0044] Fig.15 This is the Raman spectrum of 2 ppm aflatoxin and the enhancement reagent of the present invention.

[0045] In the figure: 1. Shell; 2. Mounting table; 3. Raman detection port; 4. Rotating shielding plate; 5. Mounting box; 6. Cover plate; 7. Fixed plate; 8. Slide rail; 9. Display screen; 10. Fixed sleeve; 11. Damping bearing; 12. Round rod; 13. Limiting plate; 14. Slide plate; 15. Fixed groove; 16. Channel. DETAILED DESCRIPTION

[0046] In order to make the purpose and technical solution of the present invention clearly and completely described, and the advantages more clearly understood, the embodiments of the present invention are further described in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are part of the embodiments of the present invention, rather than all of the embodiments, and are only used to explain the embodiments of the present invention, and are not used to limit the embodiments of the present invention. All other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] See also Figures 1 to 15 The present invention provides a technical solution: a device for detecting inferior oil adulteration in edible oil based on Raman spectroscopy, comprising: a Raman spectrometer body, the Raman spectrometer body comprising a shell 1, a mounting platform 2 is arranged at the front end of the shell 1, a Raman detection port 3 is fixedly mounted on the mounting platform 2, a shielding plate 4 is rotatably connected to the outer end of the mounting platform 2, the shielding plate 4 can be rotated at the upper end of the mounting platform 2, when in use, the shielding plate 4 is rotated upward to open it, the Raman detection port 3 is exposed, and the detection operation can be performed, when not in use, the shielding plate 4 is closed to protect the Raman detection port 3.

[0048] A mounting box 5 is fixedly installed on the upper side of the rear end of the shell 1, and the lower end of the mounting box 5 is connected to the inner end of the shell 1. The upper end of the mounting box 5 is rotatably connected to a cover plate 6 through a hinge. A fixing plate 7 is fixedly installed on the rear end side wall of the mounting box 5, and a slide rail 8 is fixedly installed on the front end of the fixing plate 7. A yield groove is provided at one end of the cover plate 6 to avoid the track 8. The cover plate 6 can cover the upper end of the mounting box 5, and the lower end of the track 8 is located in the mounting box 5. A display screen 9 is slidably connected to the track 8 through a sliding component. The width of the mounting box 5 is larger than the width of the display screen 9, and the display screen 9 can be stored in the mounting box 5. When not in use, the display screen 9 is rotated ninety degrees, and then slid into the mounting box 5 along the slide rail 8, and the cover plate 6 is covered to store and protect the display screen 9, thereby reducing the volume of the device and facilitating carrying.

[0049] The slide rail 8 is concave, and a fixing groove 15 is provided on the inner wall of the upper end of the slide rail 8. A channel 16 is provided on the upper end of the fixing groove 15. The sliding component includes a fixing sleeve 10 fixedly installed on the rear end side wall of the display screen 9. A damping bearing 11 is fixedly installed in the fixing sleeve 10. A round rod 12 is fixedly sleeved on the inner wall of the damping bearing 11. The outer end of the round rod 12 extends out of the damping bearing 11 and a slide plate 14 is fixedly installed. A limiting plate 13 is fixedly installed on the outer wall of the round rod 12. The outer wall of the slide plate 14 is slidably connected to the inner wall of the slide rail 8. By allowing the slide plate 14 to slide in the track 8, the position of the display screen 9 is changed, and the display screen 9 can be stopped and rotated at the outer end of the round rod 12 through the damping bearing 11.

[0050] The slide plate 14 can be inserted into the fixing groove 15. When the lower end of the slide plate 14 contacts the inner wall of the bottom end of the fixing groove 15, the round rod 12 is located in the channel 16, and the limit plate 13 contacts the outer end side wall of the slide rail 8, and the display screen 9 is fixed to the upper end of the track 8. When the display screen 9 needs to be stored, the display screen 8 is slid upward a little, and then pulled outward to separate the slide plate 14 and the fixing groove 15, so that the slide plate 14 can slide down in the track 8, and the display screen 9 can be slid into the installation box 5.

[0051] A method for detecting edible oil adulteration with inferior oil based on Raman spectroscopy specifically comprises the following steps:

[0052] S1. Sample preparation

[0053] Rapeseed oil (about 40 samples and true values ​​(oleic acid (oleic acid with a concentration higher than 70% is called high oleic acid), erucic acid (usually erucic acid with a concentration below 3% is called low erucic acid), peroxide index, acid value, etc.), soybean oil, enhanced reagent (A, nanogold), No. 6 solvent standard solution (certificate number: BWL0001, concentration 10 mg / mL±0.5, N,N-dimethylacetamide as solvent), aflatoxin B1 standard solution (Tianjin Huidi Biotechnology Co., Ltd., certificate number: HD005195, concentration 2 mg / L), benzo(a)pyrene solution in methanol standard substance (Product Quality Standard Research Center, 100 μg / ml), n-hexane, cyclohexane solution (main component of No. 6 solvent, Guangdong Lin's Chemical Reagent, analytical grade), acetonitrile (National Pharmaceutical, chromatographic grade);

[0054] S2. Doping measurement

[0055] 1) Use a 20 ml vial to mix a certain gradient of soybean oil into rapeseed oil and mix well;

[0056] 2) Use a cuvette with a 10m optical path, set the integration power to 300mW, the integration time to 12000ms, collect three times and take the average value to collect the doped Raman spectrum;

[0057] 3) Import the collected spectral data into Aopu Tiancheng modeling software for modeling, and import the built model into Raman software for sample testing and verification;

[0058] S3. Quality index measurement

[0059] 1) The rapeseed oil sample was loaded into a cuvette with a 10 ml optical path, the integration power was set to 300 mW, the integration time was set to 12000 ms, and the average value was obtained three times to collect the Raman spectrum of the rapeseed oil;

[0060] 2) Import the collected spectral data into Aopu Tiancheng modeling software for modeling, and import the built model into Raman software for sample testing and verification;

[0061] 3) Directly test the No. 6 solvent standard solution and test the spectra of n-hexane and cyclohexane;

[0062] S4. Safety index measurement

[0063] Take 1 μl of aflatoxin B1 (GB 2761-2011 requires a limit of 10 μg / Kg) or benzo(a)pyrene sample (GB2762-2022 requires a limit of 10 μg / Kg) into 1 ml of the added reagent (SERS), set the laser power to 300 mW, the integration time to 12000 ms, and collect Raman spectra. Find its characteristic peaks and make a judgment on detection and non-detection.

[0064] like Figure 5-9 They are Raman spectra of edible oil Raman, No. 6 solvent, benzopyrene standard solution, aflatoxin and other standard solutions. Figure 7 As shown, the sixth solvent, 1 / 10,000 benzo(a)pyrene (different from the methanol peak, at 998 cm -1 2ppm of aflatoxin is basically the solvent characteristic of acetonitrile.

[0065] like Fig.10 The Raman spectrum of rapeseed oil mixed with soybean oil is shown. The 1261 cm -1 、1298cm -1 、1439cm -1 、1656cm -1 Wave number modeling analysis.

[0066] Doping Modeling

[0067] Using Raman modeling software, multiple linear regression was used to model and analyze rapeseed oil adulterated with soybean oil. The R-square of the modeling was 0.97, indicating a strong correlation.

[0068] 4.2.2 Doping Verification

[0069] 7.45%, 12.36%, 17.86%, and 21.43% soybean oil adulterated samples were prepared for verification, and the measured results are as follows:

[0070] Table 4-1 Doping measurement data

[0071]

[0072]

[0073] As shown in the table above, the instrument has good stability in testing the adulterated samples of soybean oil mixed with rapeseed oil, and the absolute error of the test is within 2.5%. It can be seen that Raman can measure and collect samples of soybean oil mixed with rapeseed oil, and model the results. It can be seen that the R2 of oleic acid is 0.82, and the R2 of erucic acid is 0.81. The linear correlation coefficient is good, and the root mean square error is 5.6 and 3.63 respectively.

[0074]

[0075]

[0076] The allowable error range of fatty acid composition content is shown in Table A.2.

[0077] Table A.2 Permissible error range of fatty acid composition content

[0078]

[0079] The National Food Safety Standard for Vegetable Oil (GB2716-2018) stipulates the allowable error of fatty acid testing, with a relative error of 15% for fatty acids above 10% and a relative error of 50% for fatty acids below 10%. It can be seen that the accuracy and stability of our testing needs to be improved.

[0080] Modeling analysis was performed on the acid value and peroxide value. 2 The peroxide value is 0.93, and the R 2 is 0.53. The root mean square errors are 0.12 and 0.012 respectively.

[0081]

[0082]

[0083] Table 3 Quality indexes of pressed rapeseed oil

[0084]

[0085] "Rapeseed Oil" (GB1536-2021) stipulates that the acid value is below 3 mg / g and the peroxide value is below 0.25 g / (100 g).

[0086] like Fig.13 The following are the spectra of the measured No. 6 solvent standard solution (10 mg / ml (1% solution, N,N-dimethylamide)), n-hexane, cyclohexane (six carbon atoms, the main component of No. 6 solvent), and the Raman spectrum of edible oil. -1There were almost no characteristic peaks before. Through the characteristic peaks, theoretically, the concentration (1%) of No. 6 solvent can be identified (the limit value stipulated by the national standard is 20 mg / kg, and there is no significant signal when about 20 mg / kg of No. 6 solvent is configured and the enhanced reagent is used).

[0087] like Fig.14 and Fig.15 As shown, the 1 / 10,000 benzo(a)pyrene standard solution can be identified. The signal of the solvent is detected when testing 2ppm aflatoxin B1. There is no significant signal when using Raman enhancement reagent. (The limit value of benzo(a)pyrene aflatoxin B1 is 10μg / Kg).

[0088] Raman spectrometer can be used to identify soybean oil adulteration in rapeseed oil. The error of qualitative measurement is within 2.5%, which can be used to combat adulteration of high-end edible oils.

[0089] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for detecting inferior edible oil adulteration based on Raman spectroscopy, comprising: A Raman spectrometer body, characterized in that: the Raman spectrometer body comprises a housing (1), a mounting platform (2) is provided at the front end of the housing (1), a Raman detection port (3) is fixedly mounted on the mounting platform (2), and a shielding plate (4) is rotatably connected to the outer end of the mounting platform (2); A mounting box (5) is fixedly mounted on the upper side of the rear end of the housing (1); the upper end of the mounting box (5) is rotatably connected to a cover plate (6) via a hinge; a fixing plate (7) is fixedly mounted on the rear end side wall of the mounting box (5); a slide rail (8) is fixedly mounted on the front end of the fixing plate (7); the lower end of the rail (8) is located in the mounting box (5); a display screen (9) is slidably connected to the rail (8) via a sliding component; and the display screen (9) can be stored in the mounting box (5).

2. The device for detecting edible oil adulteration based on Raman spectroscopy according to claim 1, characterized in that: The slide rail (8) is concave in shape, a fixing groove (15) is provided on the inner wall of the upper end of the slide rail (8), and a channel (16) is provided at the upper end of the fixing groove (15).

3. The device for detecting edible oil adulteration based on Raman spectroscopy according to claim 1, characterized in that: The lower end of the installation box (5) is connected to the inner end of the housing (1), and the width of the installation box (5) is greater than the width of the display screen (9).

4. The device for detecting edible oil adulteration based on Raman spectroscopy according to claim 1, characterized in that: The sliding component comprises a fixed sleeve (10) fixedly mounted on the rear end side wall of the display screen (9), a damping bearing (11) being fixedly mounted inside the fixed sleeve (10), and a round rod (12) being fixedly sleeved on the inner wall of the damping bearing (11).

5. The device for detecting edible oil adulteration based on Raman spectroscopy according to claim 4 is characterized in that: The outer end of the round rod (12) extends out of the damping bearing (11) and is fixedly mounted with a slide plate (14); a limit plate (13) is fixedly mounted on the outer wall of the round rod (12); and the outer wall of the slide plate (14) is slidably connected to the inner wall of the slide rail (8).

6. The device for detecting edible oil adulteration based on Raman spectroscopy according to claim 5, characterized in that: The slide plate (14) can be inserted into the fixing groove (15). When the lower end of the slide plate (14) contacts the inner wall of the bottom end of the fixing groove (15), the round rod (12) is located in the channel (16), and the limit plate (13) contacts the outer end side wall of the slide rail (8).

7. A method for detecting edible oil adulteration based on Raman spectroscopy as claimed in any one of claims 1 to 6, characterized in that: The specific steps include: S1. Sample preparation Select 40 parts of different types of rapeseed oil, soybean oil, enhancement reagent (A, nanogold), solvent No. 6 (standard solution concentration 10 mg / mL ± 0.5, N, N-dimethylacetamide as solvent), aflatoxin B1 standard solution, benzo(a)pyrene solution in methanol standard substance, n-hexane, cyclohexane solution, acetonitrile; S2. Doping measurement 1) Use a 20 ml vial to mix a certain gradient of soybean oil into rapeseed oil and mix well; 2) Use a cuvette with a 10m optical path, set the integration power to 300mW, the integration time to 12000ms, collect three times and take the average value to collect the doped Raman spectrum; 3) Import the collected spectral data into Aopu Tiancheng modeling software for modeling, and import the built model into Raman software for sample testing and verification; S3. Quality index measurement 1) The rapeseed oil sample was loaded into a cuvette with a 10 ml optical path, the integration power was set to 300 mW, the integration time was set to 12000 ms, and the average value was obtained three times to collect the Raman spectrum of the rapeseed oil; 2) Import the collected spectral data into Aopu Tiancheng modeling software for modeling, and import the built model into Raman software for sample testing and verification; 3) Directly test the No. 6 solvent standard solution and test the spectra of n-hexane and cyclohexane; S4. Safety index measurement Take 1 μl of aflatoxin B1 (GB 2761-2011 requires a limit of 10 μg / Kg) or benzo(a)pyrene sample (GB2762-2022 requires a limit of 10 μg / Kg) into 1 ml of added reagent (SERS), set the laser power to 300 mW, the integration time to 12000 ms, collect Raman spectra, find its characteristic peaks, and make a detection or non-detection judgment.

8. The method for detecting edible oil adulteration with inferior oil based on Raman spectroscopy according to claim 7, characterized in that: The rapeseed oil mixed with soybean oil in S1 was modeled and analyzed using multiple linear regression, and the R square of the modeling was 0.97, indicating a strong correlation.

9. The method for detecting edible oil adulteration with inferior oil based on Raman spectroscopy according to claim 7, characterized in that: The ratio of soybean oil mixed in rapeseed oil in S1 was 7.45%, 12.36%, 17.86% and 21.43% for verification, and samples were collected for modeling. The R2 of oleic acid was 0.82, and the R2 of erucic acid was 0.

81. The linear correlation coefficient was good, and the root mean square errors were 5.6 and 3.63 respectively.

10. The method for detecting edible oil adulteration with inferior oil based on Raman spectroscopy according to claim 7, characterized in that: The acid value and peroxide value are modeled and analyzed, and the R 2 The peroxide value is 0.

93. 2 The root mean square errors are 0.12 and 0.012 respectively, which can identify the 1 / 10,000 benzo(a)pyrene standard solution. The signal of 2ppm aflatoxin B1 is the solvent signal, and there is no significant signal when using Raman enhancement reagent.

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