Raman spectrum accurate and efficient collection device for detection of residual clenbuterol

Abstract

The application mainly comprises a general sample tank for Raman detection of trace elements of agricultural products, a control unit, a spectral detection unit, a laser, a power supply, a display screen and a shell body, and the internal structure is a spherical structure, which can reflect and converge light to the Raman probe. The detection direction of the Raman probe is from bottom to top, which can keep the distance between the probe and the sample fixed; compared with the traditional detection method, the sample holding groove needs more liquid sample to be detected, which reduces the instability of the detection result caused by the evaporation of the liquid water solution due to the long integral time of Raman light; the conductive cone of the sample holding groove generates a local electric field after being electrified due to the polarization caused by the electric field, and when the molecules of the detected substance are in the local electric field, the Raman scattering light intensity of the detected substance is improved. The device can realize rapid detection of the content of ractopamine in pork, and has the advantages of small size, simple operation, accurate detection, high automation and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of Raman detection of trace elements in agricultural products, and particularly relates to a Raman spectrum precise and efficient acquisition device for detection of residual clenbuterol. BACKGROUND

[0002] Raman spectrum has a fingerprint effect, and characteristic peaks of the spectrum reflect chemical bond vibration and rotation information of molecules of a measured object, and thus can reflect chemical structures of molecules of certain substances. 4 6 Surface enhanced Raman scattering technology is to adsorb molecules of a measured object to a substrate made of noble metal particles such as gold and silver, so that Raman signals are enhanced by 10 -1 Raman spectrum technology and surface enhanced Raman spectrum technology are widely used in fields such as agriculture, biology, chemistry, food safety, environmental detection, clinical medicine, life science, and petroleum chemical industry.In actual use, due to high sensitivity of Raman spectrum, uniformity, state, shape of a sample, mixing uniformity of the sample and an enhanced substrate, and distance between the sample and a light source, factors will affect a detection result, and cause fluctuation of the detection result. In addition, Raman spectrum is mainly acquired by a Raman spectrometer, and there are various types of Raman spectrometers on the market, most of which can detect spectrum at a Raman shift of 200-3500 cm SUMMARY

[0003] To solve the problem, the present application provides a general sample tank for Raman detection of trace elements in agricultural products according to liquid content of a measured sample, which comprises a general sample tank for Raman detection of trace elements in agricultural products, a control unit, a spectrum detection unit, a laser, and an outer shell. The general sample tank for Raman detection of trace elements in agricultural products, the control unit, the spectrum detection unit, and the laser are located inside the outer shell. The spectrum detection unit is arranged at a lower part of the general sample tank for Raman detection of trace elements in agricultural products, and comprises an optical fiber, a Raman probe, a laser, and a Raman spectrum detection chip, and is used to acquire and process spectrum of the measured sample. The general sample tank for Raman detection of trace elements in agricultural products comprises a sample containing part, an ultrasonic transducer, a spherical upper cover, and a fixing support. The sample containing part comprises a sample containing groove and quartz glass. The upper half of the sample containing groove is a hemisphere, and the lower half is a cylinder. The fixing support is arranged above the sample containing part, and the groove bottom is the quartz glass and is used to contain the measured sample. The fixing support is arranged below the Raman probe, and the measured sample can be detected from bottom to top.

[0004] On the basis of the above scheme, the laser emits excitation light to irradiate the sample, and then the Raman scattered light of the sample is collected by the Raman probe and transmitted to the Raman spectrum detection chip through the optical fiber.

[0005] On the basis of the above scheme, after the to-be-tested liquid is placed, the to-be-tested liquid concave liquid surface and the sample containing concave groove and spherical upper cover approximately form an integrating sphere, and the refraction of light inside the integrating sphere is utilized.

[0006] On the basis of the above scheme, while the to-be-tested liquid is excited by the laser, the electrically conductive cone in the sample containing concave groove starts to discharge to form a local electric field, a part of the scattered light directly transmits through the quartz glass and is collected by the Raman probe below, and another part enters the approximately spherical space composed of the to-be-tested liquid concave liquid surface, the sample containing concave groove and the upper cover, and after reflection and mixing, transmits through the quartz glass again and is collected by the Raman probe below.

[0007] On the basis of the above scheme, the circular equation of the approximate integrating sphere cross section composed of the spherical upper cover, the sample containing part, the sample containing concave groove spherical part and the to-be-tested sample is established as follows:

[0008] Suppose that point a is the lowest point of the concave liquid surface, and the coordinates are (0, 0);

[0009] Suppose that point b is the intersection point of the left side of the concave liquid surface and the sample containing part, and the coordinates are (m, n);

[0010] Suppose that point c is the intersection point of the right side of the concave liquid surface and the sample containing part, and the coordinates are (-m, n);

[0011] Suppose that m represents the horizontal distance of point b from point a, and n represents the vertical distance of point b from point a;

[0012] The approximate integrating sphere cross section equation is derived as follows:

[0013] ;

[0014] Wherein, x and y represent the coordinates of any point on the cross section on the x and y axes respectively, and the value range of x and y is as follows:

[0015] .

[0016] On the basis of the above scheme, the ultrasonic transducer is fixedly arranged around the sample containing part for uniformly mixing the to-be-tested sample inside the sample containing part.

[0017] On the basis of the above scheme, buttons are arranged on the side surface of the shell, and the ultrasonic transducer and the electrically conductive cone are controlled to be turned on and off by the buttons.

[0018] On the basis of the above-mentioned scheme, the inner surface of the sample holding part is made of aluminum material.

[0019] On the basis of the above-mentioned scheme, the outer shell side is provided with a display screen for displaying the content of the sample to be measured.

[0020] On the basis of the above-mentioned scheme, the outer shell further comprises a power supply.

[0021] The beneficial effects of the present application are:

[0022] The universal sample tank for Raman detection of trace elements of agricultural products can be used for detection of all liquid samples. During detection, the quartz glass interval from the bottom to the top detects the sample from the bottom, and the distance between the Raman probe and the sample can be fixed, solving the problem of fluctuation of detection results caused by inconsistent shape and unevenness of the sample. Secondly, based on the concave liquid surface of the sample to be measured and the sample holding groove and the spherical upper cover, an integral sphere is approximately formed, and the refraction of light inside the integral sphere makes the collected Raman signal of the sample more uniform during detection. Then, compared with the traditional detection method, the sample holding groove of the sample to be measured holds more sample during sample detection, and the energy generated by the Raman light under the same integration time causes the change of the concentration of clenbuterol caused by the evaporation of the aqueous solution in the sample to be measured to be smaller. Finally, when the Raman light irradiates on the sample to be measured, the electrically conductive cone in contact with the sample to be measured generates a local electric field, which improves the spectral intensity of the characteristic peak of clenbuterol collected by the Raman probe. The Raman spectrum detection chip mainly detects the Raman scattering spectrum characteristic peaks of clenbuterol, ractopamine and salbutamol, has high resolution at the characteristic peak position of clenbuterol, ractopamine and salbutamol, small volume, accurate detection results and other advantages. The display screen can be used to display the content of the sample to be measured. The device can realize rapid detection of the content of clenbuterol in pork by clicking the button, and has the advantages of small volume, simple operation, accurate detection, high degree of automation and the like. BRIEF DESCRIPTION OF DRAWINGS

[0023] The present application has the following drawings:

[0024] Figure 1 Schematic diagram of traditional droplet sample detection method.

[0025] Figure 2 Cross-sectional view of the universal sample tank for Raman detection of trace elements of agricultural products.

[0026] Figure 3 Schematic diagram of the light path effect in the liquid sample holding part.

[0027] Figure 4 Schematic diagram of the two-dimensional coordinate system of the spherical groove in the sample holding part.

[0028] Figure 5 Spectrum curve schematic diagram of traditional spectrum acquisition mode and new spectrum acquisition mode.

[0029] Figure 6 Light intensity comparison chart of traditional spectrum acquisition mode and new spectrum acquisition mode at 1002cm -1 , 1259cm -1 and 1590cm -1 .

[0030] Figure 7 Internal structure diagram of Raman spectrum acquisition device for "lean meat powder" residue detection.

[0031] Figure 8 Overall appearance diagram of Raman spectrum acquisition device for "lean meat powder" residue detection.

[0032] In the figure:

[0033] 1-detection probe, 2-spherical upper cover, 3-button, 4-fixing support, 5-Raman probe, 6-quartz glass, 7-ultrasonic transducer, 8-sample holding groove, 9-outer shell, 10-display screen, 11-power supply, 12-Raman spectrum detection chip, 13-laser, 14-optical fiber, 15-Raman probe, 16-spectrum detection unit, 17-universal sample groove for Raman detection of trace elements in agricultural products, 18-liquid to be detected, 19-scattered light, 20-sample excitation light. DETAILED DESCRIPTION

[0034] The application will be further described in detail below. Figures 1-8 The detection stability of Raman spectrum is affected by the following parameters:

[0035] 1) The content, shape and detected position of the liquid sample to be detected;

[0036] 2) The distance between the sample and the light source and the probe often changes due to the volatilization of the sample or the different detected positions during detection, so that the light source intensity and the signal amount received by the probe change every time;

[0037] 3) The mixing uniformity between the sample and the enhanced substrate often leads to deviation in the signal enhancement effect of the same enhanced substrate on the same sample.

[0038] 4) Most of the Raman spectrometers currently produced on the market are general-purpose spectrometers, which are not targeted, and the volume and resolution cannot be achieved at the same time, which hinders the promotion and application of Raman spectrum detection technology.

[0039] 5) For example,

[0040] Figure 1 ​As shown in Figure a, when detecting droplet samples, the detection results are unstable due to differences in droplet height at the three detection positions indicated by the arrows. Furthermore, the droplet height changes in real time due to droplet evaporation, which also causes significant variations in the detection results. Figure 1 As shown in b, when the height of the detection probe from the sample changes from d1 to d2 due to different droplet sizes and different droplet detection positions, the angle of the sample scattered light received by the probe changes from β1 to β2. The calculation method is shown in formulas 1 and 2.

[0041] ;

[0042] ;

[0043] Where L1 is the width of the Raman probe, d1 and d2 are the heights of the detection probe from the sample, and β1 and β2 are the angles formed by the two ends of the Raman probe and the highest point of the sample droplet before and after the change in sample height, respectively. Figure 1 As shown in b. Suppose the angle of the sample scattered light received by the probe changes from β1 to β2. It can be clearly determined that β1>β2. Therefore, the scattered light collected by the Raman probe is reduced by (|β1-β2| / β1)%.

[0044] like Figure 2 As shown, a universal sample holder 17 for Raman detection of trace elements in agricultural products includes a sample holding component 8, an ultrasonic transducer 7, a spherical top cover 2, a fixing bracket 4, and a button 3. The sample holding component 8, located above the fixing bracket 4, is used to hold the sample to be tested. The upper half of the sample holding component 8 is hemispherical, and the lower half is cylindrical. The cylindrical part is surrounded by evenly arranged conductive cones. After holding a certain volume of liquid, the concave surface of the liquid and the sample holding component 8 can form an approximately spherical shape. A quartz glass 6 is placed at the bottom, allowing Raman excitation light to pass through and detect the sample. The inner surface of the sample holding component 8 is made of aluminum to eliminate material interference. It can be used in conjunction with the spherical top cover 2 to place the sample in a dark environment, eliminating interference from ambient light. The ultrasonic transducer 7 is located around the sample holding component and can perform ultrasonic vibration on the sample, ensuring uniform mixing. The button 3 is used to control the on / off state of the ultrasonic transducer 7 and the conductive cones in the sample holding groove 8. A space is provided below the fixing bracket 4 for fixing the universal Raman probe 5, so that the Raman probe 5 is directly below the quartz glass 6. This ensures that the distance between the Raman probe 5 and the sample is the same during detection, and is not affected by the shape of the sample, resulting in more stable detection. When a certain volume of the liquid to be tested is contained, the concave meniscus of the liquid to be tested and the sample holding component 8 form an approximately spherical shape, such as... Figure 3As shown, the sample 18 to be tested is excited by sample excitation light 20, at the same time, the electrically conductive cone in the sample holding groove 8 starts to discharge, forming a local electric field, which has an enhancing effect on the characteristic peak spectrum of the sample to be tested. A part of the scattered light 19 directly transmits through the quartz glass 6 and is collected by the Raman detection probe 5 below, and another part enters the approximate spherical space composed of the sample groove and the upper cover, and is collected by the Raman detection probe 5 below after being reflected and mixed. Therefore, the collected sample excitation light is stronger and more uniform.

[0045] As shown in Figure 3 , the sample holding part 8 and the spherical upper cover form a sealed space. Let the lowest point of the concave liquid surface be point a, and the points where the end points of the concave liquid surface coincide with the sample holding part 8 be points b and c respectively. Take the line connecting points a, b and c as an approximate circular arc, which forms an approximate integrating sphere with the sample groove, and point d is the center of the integrating sphere; the Raman scattered light of the sample to be tested is emitted from point a, and for the incident light rays whose sum of incident angle and reflection angle is a multiple of 180°, the light path will coincide with the first incidence point, i.e. it is reflected downward into the Raman probe.

[0046] The number of Raman light collected by the Raman probe 5 is only related to the spherical groove part of the sample holding part 8 in the structure of the device, and the spherical groove part of the sample holding part 8 is related to the circular equation of the cross section of the spherical groove part of the sample holding part 8, i.e. the circular equation of the cross section of the approximate integrating sphere composed of the cover 2, the spherical groove part of the sample holding part 8 and the sample to be tested. The process of establishing the circular equation is as follows: first, the two-dimensional coordinate system of the circular equation is established as shown in Figure 4 , the x-axis direction is parallel to the direction of the line connecting points b and c and passes through point a, and the y-axis direction is the vertical upward direction of the line connecting points a and d, and the origin is Figure 3 point a, which is the lowest point of the concave liquid surface, and the coordinates of point a are (0, 0), and Figure 3 , points a, b and c are taken as the reference, and m represents the horizontal distance of point b from point a, and n represents the vertical distance of point b from point a. When the concave liquid surface of the sample to be tested is formed as shown in Figure 3 , m = 10 mm and n = 2.207 mm. Because points b and c are symmetric about the y-axis, the coordinates of points b and c are (m, n) and (-m, n) respectively. Because points a, b and c are not collinear, the equation of the cross section of the approximate integrating sphere composed of the cover 2, the spherical groove part of the sample holding part 8 and the sample to be tested is as shown in formula 3:

[0047] ;

[0048] , x and y represent the coordinates of any point on the cross section in the x and y axes respectively, and the value range of x and y is

[0049] .

[0050] When the width of the Raman probe is consistent with the height of the sample from the probe distance, the voltage of the sample containing groove 8 is U = 10V, the height of the single cone in the sample containing groove is h = 1mm, and the bottom radius is r = 0.3mm. The 50 10 ug / mL ractopamine pork samples are repeatedly tested, the average increase of the scattered light intensity collected by the Raman probe is 20%, and the relative standard deviation of each peak of the scattered spectrum is reduced from 4%-6% to 1%-3%. Figure 5 The average curve comparison of the spectra of 50 10 ug / mL ractopamine pork sample solutions by the traditional spectrum collection method and the new spectrum collection method in the patent is shown. Compared with the traditional spectrum collection method, the new spectrum collection method collects more Raman light and has higher light intensity.

[0051] According to the experimental data and the reference, the Raman characteristic peaks of ractopamine are mainly 831cm -1 , 1002cm -1 , 1169cm -1 , 1259cm -1 , 1501cm -1 and 1590cm -1 . Figure 5 The Raman characteristic peaks of ractopamine are 831cm -1 , 1169cm -1 and 1501cm -1 , and there are no obvious peaks in the two spectrum curves. As can be seen from Figure 6 , the light intensity of the new spectrum collection method is obviously higher than that of the traditional spectrum collection method at 1002cm -1 , 1259cm -1 and 1590cm -1 , which proves that the Raman spectrum collection method of the device is better than the traditional Raman spectrum collection method.

[0052] As shown in Figure 7 , the Raman spectrum collection device for "lean meat" residue detection mainly includes a general sample groove 17 for trace element Raman detection of agricultural products, a control unit 16, a spectrum detection unit, a power supply 11, a display screen 10 and a shell 9.

[0053] The spectrum detection unit includes an optical fiber 14, a laser 13, a Raman probe 15 and a Raman spectrum detection chip 12, which can be used for spectrum acquisition of the sample to be tested.

[0054] In operation, the excitation light emitted by the laser 13 is transmitted through the optical fiber 14 and the Raman probe 15 to irradiate the sample, and then the Raman scattered light of the sample is collected by the Raman probe 15 and transmitted through the optical fiber 14 to the Raman spectrum detection chip 12.

[0055] The Raman spectrum detection chip 12 mainly receives the scattered light intensity at the Raman characteristic peak displacement of "lean meat powder", and has the advantages of small volume and low price.

[0056] The control unit 16 calculates and processes the Raman scattered light intensity obtained by the Raman spectrum detection chip 12, judges whether "lean meat powder" is contained, and displays on the display screen 10.

[0057] In a specific embodiment, the whole device is detected by one-button, and the overall size is 80mmx97mmx127mm. The overall appearance of the device is shown in Figure 8 The important components in the device are all in the shell 9 except the spherical upper cover 2 and the display screen 10. The device has the advantages of small volume, stable detection result, low price, and easy to carry.

[0058] The above embodiments are only used to illustrate the patent of the present application, and are not limited to the patent of the present application. The ordinary skilled in the art can make various changes and modifications without departing from the spirit and scope of the patent of the present application. Therefore, all equivalent technical solutions also belong to the scope of the patent of the present application, and the patent protection scope of the patent of the present application should be defined by the claims.

[0059] The contents not described in detail in the specification belong to the prior art known to those skilled in the art.

Claims

1. A Raman spectrum precise and efficient collection device for detection of clenbuterol residues, characterized in that, The general sample tank for Raman detection of trace elements in agricultural products, a control unit, a spectral detection unit, a laser and a shell are included. The general sample tank for Raman detection of trace elements in agricultural products, the control unit, the spectral detection unit and the laser are located inside the shell. The spectral detection unit is arranged at the lower part of the general sample tank for Raman detection of trace elements in agricultural products and includes an optical fiber, a Raman probe, a laser and a Raman spectrum detection chip for obtaining the spectrum of a sample to be detected. The general sample tank for Raman detection of trace elements in agricultural products includes a sample holding component, an ultrasonic transducer, a spherical upper cover and a fixing support. The sample holding component includes a sample holding groove and quartz glass. The upper half of the sample holding groove is a hemisphere, and the lower half is a cylinder, and the periphery of the cylinder is embedded with evenly arranged conductive cones; the sample holding component is fixed above the fixing support, and the groove bottom is the quartz glass for holding the sample to be detected; the fixing support below is used for fixing the Raman probe to detect the sample from bottom to top; the conductive cones form a local electric field after being electrified to enhance the Raman scattering light intensity of the sample to be detected; The ultrasonic transducer is integrated around the sample holding component to uniformly mix the sample through ultrasonic oscillation; the sample holding groove, the spherical upper cover and the liquid concave surface of the liquid to be detected together form an integrating sphere structure, so that the scattered light is collected by the Raman probe through the quartz glass after multiple reflections; After holding the liquid to be detected, the liquid concave surface of the liquid to be detected, the sample holding groove and the spherical upper cover approximately form an integrating sphere, and the light is refracted inside the integrating sphere; When the liquid to be detected is excited by the laser, the conductive cones in the sample holding groove begin to discharge and form a local electric field, a part of the scattered light directly transmits through the quartz glass and is collected by the Raman probe below, and another part enters the approximately spherical space composed of the liquid concave surface of the liquid to be detected, the sample holding groove and the upper cover, and is collected by the Raman probe below again after reflection and mixing.

2. The Raman spectrum precise and efficient collection device for clenbuterol residue detection according to claim 1, characterized in that, The laser emits excitation light to irradiate the sample, and then the Raman scattering light of the sample is collected by the Raman probe and transmitted to the Raman spectrum detection chip through the optical fiber.

3. The Raman spectrum precise and efficient collection device for clenbuterol residue detection according to claim 2, characterized in that, The circular equation of the approximate integrating sphere cross section formed by the spherical upper cover, the sample holding component, the sample groove spherical part and the sample to be detected is established as follows: Point a is the lowest point of the liquid concave surface, and the coordinates are (0, 0); Point b is the intersection point of the left side of the liquid concave surface and the sample holding component, and the coordinates are (m, n); Point c is the intersection point of the right side of the liquid concave surface and the sample holding component, and the coordinates are (-m, n); m represents the horizontal distance of point b from point a, and n represents the vertical distance of point b from point a; The approximate integrating sphere cross section equation is derived as follows: ; Where x and y represent the coordinates of any point on the cross section on the x and y axes, respectively, and the value range of x and y is as follows: 。 4. The Raman spectrum precise and efficient collection device for clenbuterol residue detection according to claim 1, characterized in that, The side of the shell is provided with a button to control the opening and closing of the ultrasonic transducer and the electrification of the conductive cones.

5. The Raman spectrum precise and efficient collection device for clenbuterol residue detection according to claim 1, characterized in that, The inner surface of the sample holding component is made of aluminum.

6. The Raman spectrum precise and efficient collection device for clenbuterol residue detection according to claim 1, characterized in that, The outer shell side is provided with a display screen for displaying test information.

7. The Raman spectrum precise and efficient collection device for clenbuterol residue detection according to claim 1, characterized in that, The outer shell further comprises a power supply inside.

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