High-salt food heavy metal detection device and detection method

Abstract

The application discloses a high-salt food heavy metal detection equipment and a detection method, and applies a dissolution voltammetry method for measurement, and comprises an outer casing, an electrode cover and a stirring device, wherein a thermal ionization chamber is preinstalled with an electrolyte, the bottom of the outer casing is provided with the thermal ionization chamber, one end of the thermal ionization chamber is communicated with an air inlet channel, the air inlet channel is installed with a hot air blower, the hot air blower blows hot air into the thermal ionization chamber to accelerate sample decomposition ionization. The middle part of the outer casing is provided with a partition, the partition is provided with the stirring device above and the thermal ionization chamber below, and the inner wall of the thermal ionization chamber is provided with a heat preservation layer to reduce heat loss. In use, the other end of the thermal ionization chamber is provided with an air outlet channel and a butterfly valve, when the sample enters the thermal ionization chamber, the hot air blower blows hot air to accelerate sample decomposition ionization, and after the sample is completely decomposed, the butterfly valve is closed to make the sample solution enter a rotating container.

Description

Technical Field

[0001] This invention relates to the field of electrochemical detection equipment technology, specifically to a heavy metal detection device and method for high-salt foods. Background Technology

[0002] Electrochemical methods are a rapidly developing approach in recent years, characterized by low detection limits, high sensitivity, and the ability to determine 10... -7 ~10 -9 This method can continuously measure multiple metal ions at a concentration of mol / L. The instruments used are relatively simple and the operation is convenient, making it an excellent trace analysis technique.

[0003] The main determination method consists of two steps. The first step is "electrolysis", which involves electrolyzing and depositing the ions to be measured at a constant potential. The second step is "dissolution", which involves applying a reverse voltage to the working electrode after enrichment, re-oxidizing the metal into ions and returning them to the solution, generating an oxidation current. The voltage-current curve, i.e., the voltammetric curve, is recorded and used as the basis for qualitative analysis.

[0004] However, this method also has its limitations. Since the object of detection is food, food is prone to producing deposits during the electrolysis process. Furthermore, during the electrolysis-electrodeionization process, the ions come into contact with the air and are affected by the deposits and oxide layer, resulting in insufficient stirring. This makes it difficult to obtain repeatable results, thereby reducing the measurement accuracy due to the influence of metal oxidation. Summary of the Invention

[0005] Therefore, the present invention provides a heavy metal detection device and method for high-salt foods, which adopts a new stirring method to solve the problem of reduced measurement accuracy caused by the generation of sediments by electrochemical methods in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] According to the first aspect of the invention

[0008] This invention discloses a heavy metal detection device for high-salt foods, which uses the stripping voltammetry method for measurement, including:

[0009] The outer casing has a thermal ionization chamber at the bottom, which is filled with electrolyte. One end of the thermal ionization chamber is connected to the air inlet channel, which is equipped with a hot blower and has an isolation component in the middle.

[0010] The electrode cover is screwed to the outer casing at the bottom.

[0011] A stirring device, disposed within the outer casing and connected to a drive motor, includes:

[0012] A rotating container is provided with a solenoid valve at the bottom and is connected to the thermal ionization chamber through the isolation component;

[0013] Several stirring components are arranged horizontally along the outer edge of the rotating container. When the rotating container rotates, the stirring components rotate synchronously.

[0014] The other end of the thermal ionization chamber is equipped with an air outlet channel and a butterfly valve. When the sample enters the thermal ionization chamber, the hot blower blows in hot air to accelerate the decomposition and ionization of the sample. After the sample is completely decomposed, the butterfly valve closes, allowing the sample solution to enter the rotating container.

[0015] Furthermore, the stirring component includes:

[0016] The connecting shaft has a stirring rack at the tail end and a bevel gear at the head end;

[0017] The bevel gear meshes with the ring rack for transmission, and the ring rack is installed inside the outer casing;

[0018] When the rotating container rotates, it drives the bevel gear to rotate, thereby driving the stirring rack to rotate.

[0019] Furthermore, the outer casing includes:

[0020] The shell has an inner liner inside, the inner wall of which is fitted with the annular toothed rack, and a vent is provided at the bottom.

[0021] The motor slot contains a drive motor, and its outer edge is connected to the inner liner.

[0022] The center hole is located at the center of the bottom of the inner liner.

[0023] Furthermore, the rotating container includes:

[0024] The cylinder has a wheel at the top and a water-permeable pipe at the bottom, with a solenoid valve at the end of the water-permeable pipe.

[0025] There are several assembly holes arranged along the axial direction of the cylinder, and the connecting shaft is inserted inside them.

[0026] Furthermore, the wheel body is a gear or a pulley.

[0027] Furthermore, the electrode cap includes:

[0028] The cap has an electrode disk at the bottom, and a capillary tube is located at the center of the electrode disk. The capillary tube contains a platinum wire for conducting electricity.

[0029] The mercury capsule contains a needle valve that is connected to a capillary tube. When the needle valve is pressed, liquid mercury in the mercury capsule flows out from the capillary tube to form mercury droplets, which serve as the anode in the electrolytic cell.

[0030] Furthermore, the rotating container is connected to an oscilloscope.

[0031] Furthermore, the inner wall of the thermo-ionization chamber is provided with a heat insulation layer.

[0032] Furthermore, the isolation element includes:

[0033] The isolation plate has a vacuum pump installed at its outer edge, and the vacuum pump is connected to the outside.

[0034] The water supply pipe is fixedly installed on the isolation plate, with its top connected to the water permeable pipe and its bottom connected to the thermo-ionization chamber.

[0035] The present invention has the following advantages:

[0036] This invention utilizes a thermal ionization chamber to dissolve samples and enhances the dissolution and ionization effect by introducing a hot gas flow. When the sample solution enters the rotating container, the rotating container rotates, causing the stirring component to revolve. Simultaneously, the stirring component itself also rotates. Therefore, compared with existing technologies, this invention can effectively improve stirring efficiency and increase the rate of ion diffusion. At the same time, residual deposits in the sample solution are subjected to centrifugal force and accumulate on the inner wall of the rotating container, thereby reducing interference with the electrodes and improving detection accuracy.

[0037] According to a second aspect of the invention,

[0038] This invention discloses a detection method using the high-salt food heavy metal detection equipment described above, comprising the following steps:

[0039] 1. Place the sample and electrolyte into the thermal ionization chamber, and start the hot blower to blow hot air in, so that the sample decomposes and ionizes in the electrolyte;

[0040] 2. Wait for the solute in the thermal ionization chamber to precipitate, then close the butterfly valve. The hot blower is restarted to send the supernatant suspended in the thermal ionization chamber into the rotating container through the water inlet pipe. The rotating container rotates, which in turn drives the stirring component to rotate.

[0041] 3. Pre-electrolysis is performed using the anodic stripping voltammetry method. After the test solution is deoxygenated, the metal ions are electrolyzed at the potential where the limiting current is generated, which is on the capillary tube, and are enriched on the electrode plate. After standing for 30 seconds or 1 minute, the working electrode is scanned from negative to positive. The metal electrolyzed on the electrode is then re-oxidized. The anodic wave and the ratio of peak current (wave height) to the measured ion are recorded.

[0042] The present invention has the following advantages:

[0043] This method allows for direct testing of physical samples without the need for pre-prepared solutions. Furthermore, the dissolution and precipitation process removes most of the sediment, effectively reducing the adverse effects of sediment on the accuracy of the testing equipment. Attached Figure Description

[0044] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0045] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0046] Figure 1 Top view of the heavy metal detection device for high-salt food provided by the present invention;

[0047] Figure 2 Provided by the present invention Figure 1 Sectional view at AA;

[0048] Figure 3 A perspective view of the electrode cover provided by the present invention;

[0049] Figure 4 A perspective view of the rotating container provided by the present invention;

[0050] Figure 5 A perspective view of the outer casing provided for this invention;

[0051] Figure 6 A perspective view of the stirring component provided by the present invention;

[0052] Figure 7 A perspective view of the isolation component provided by the present invention;

[0053] In the diagram: 1 Outer casing; 11 Housing; 12 Inner liner; 13 Motor slot; 14 Exhaust port; 2 Thermal ionization chamber; 3 Electrode cover; 31 Sealing cap; 32 Electrode disc; 33 Mercury bladder; 34 Needle valve; 35 Capillary tube; 4 Drive motor; 5 Stirring device; 51 Rotary container; 511 Cylinder; 512 Assembly hole; 513 Wheel; 514 Water permeable pipe; 52 Stirring component; 521 Connecting shaft; 522 Stirring frame; 523 Bevel gear; 53 Solenoid valve; 54 Ring rack; 6 Isolation component; 61 Isolation plate; 62 Vacuum pump; 64 Water inlet pipe; 7 Air inlet channel; 8 Air outlet channel; 9 Hot blower. Detailed Implementation

[0054] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] Please refer to this as well. Figures 1-7 This invention discloses a heavy metal detection device for high-salt foods, which uses the stripping voltammetry method for measurement. It includes an outer casing 1, an electrode cover 3, and a stirring device 5. The thermal ionization chamber 2 is pre-filled with an electrolyte (such as an acidic or alkaline solution). The thermal ionization chamber 2 is located at the bottom of the outer casing 1, and one end of the thermal ionization chamber 2 is connected to an air inlet channel 7. A hot air blower 9 is installed in the air inlet channel 7, blowing hot air into the thermal ionization chamber 2 to accelerate sample decomposition and ionization. An isolation element 6 is located in the middle of the outer casing 1. The stirring device 5 is located above the isolation element 6, and the thermal ionization chamber 2 is located below it. The inner wall of the thermal ionization chamber 2 is provided with an insulation layer to reduce heat loss.

[0056] Specifically, the stirring device 5 is housed inside the outer casing 1 and connected to the drive motor 4. It includes a rotating container 51 and stirring components 52. The bottom of the rotating container 51 is equipped with a solenoid valve 53 and is connected to the thermal ionization chamber 2 via an isolator 6. A number of stirring components 52 are horizontally positioned along the outer edge of the rotating container 51. When the rotating container 51 rotates, the stirring components 52 rotate synchronously. The other end of the thermal ionization chamber 2 is equipped with an air outlet 8 and a butterfly valve. When the sample enters the thermal ionization chamber 2, a hot blower 9 blows in hot air to accelerate the decomposition and ionization of the sample. After the sample is completely decomposed, the butterfly valve closes, allowing the sample solution to enter the rotating container 51. In this embodiment, the bottom of the electrode cover 3 is screwed to the outer casing 1, and the electrode disk 32 on the electrode cover 3 is in direct contact with the sample solution for electrochemical analysis.

[0057] In this embodiment, as Figure 6The stirring component 52 includes a stirring frame 522, a connecting shaft 521, and a bevel gear 523. The stirring frame 522 is located at the tail end of the connecting shaft 521. The shape of the stirring frame 522 is not unique and it mainly serves to stir horizontally. The bevel gear 523 is located at the head end of the connecting shaft 521. The bevel gear 523 is meshed with a ring rack 54 for transmission. The ring rack 54 is installed inside the outer casing 1. When the rotating container 51 rotates, it drives the bevel gear 523 to rotate, thereby driving the stirring frame 522 to rotate. Thus, while the rotating container 51 rotates, the stirring frame can not only axially lag with the rotating container 51 and revolve with the rotating container 51, but also rotate on its own axis, thereby greatly improving the stirring efficiency and shortening the time required for the electrolysis and enrichment of the electrolyte solution.

[0058] In some embodiments, such as Figure 5 The outer casing 1 includes a housing 11, a motor slot 13, and a central hole 15. A drive motor 4 is installed inside the motor slot 13, and its outer edge is connected to the inner liner 12. A central hole 15 is located at the center of the bottom of the inner liner 12, and a water-permeable pipe 514 is inserted into the central hole 15 to facilitate the rotation of the rotating container 51 at the center of the inner liner 12. This facilitates the transmission connection between the drive motor 4 and the container 51. The inner liner 12 is located inside the housing 11, and a ring-shaped rack 54 is mounted on the inner wall of the inner liner 12. An exhaust port 14 is located at the bottom of the housing 11 and is connected to the air outlet channel 8.

[0059] In this embodiment, as Figure 4 The rotating container 51 includes a cylindrical body 511 and mounting holes 512. The top of the cylindrical body 511 is equipped with a wheel 513, which is a gear or pulley. In other words, the drive motor 4 can drive the rotating container 51 to rotate via belt drive or gear drive. The bottom of the rotating container 51 is also equipped with a water permeable pipe 514, and an electromagnetic valve 53 is installed at the end of the water permeable pipe 514. The electromagnetic valve 53 controls whether the sample solution can enter the rotating container 51. Furthermore, a number of mounting holes 512 are arranged axially along the cylindrical body 511, and a connecting shaft 521 is inserted inside each hole. The connecting shaft 521 is adapted to rotate within the mounting holes 512, thereby driving the stirring rack 522 to rotate. It should be noted that when the rotating container 51 rotates, the sample solution in the rotating container 51 will be centrifuged, causing the sediment to accumulate on the inner wall of the rotating container 51. At the same time, due to the rotation of the stirring rack 522, the sediment will be stirred and the ion diffusion will be accelerated, thereby further accelerating the electrochemical enrichment rate and shortening the detection time.

[0060] In some embodiments, such as Figure 3The electrode cap 3 includes a cover 31 and a mercury sac 33. The cover 31 has an electrode disk 32 at its bottom, which serves as the working electrode. During enrichment under current, it absorbs cations to form a metal. A capillary tube 35 is located at the center of the electrode disk 32, containing a platinum wire to enhance conductivity. The capillary tube 35 is connected to a needle valve 34, which is located inside the mercury sac 33. Thus, the mercury sac 33 and the capillary tube 35 form a dropping mercury electrode. During current application, a push-pull electromagnet actuates the needle valve 34, forming mercury droplets. The mercury droplets flow out from the lower end of the capillary tube and form an electrode (each droplet continuously grows from small to large; when it reaches a diameter of approximately 0.5–1.0 mm, it drips down due to gravity). This electrode has the advantages of a small surface area, high current density, and easy polarization, significantly improving the reproducibility of analytical results.

[0061] In this embodiment, the capillary tube 35 is positioned directly opposite the axis of the rotating container 51, and the push-pull electromagnet can be connected to a microcontroller to automatically control the time of droplet formation.

[0062] In some embodiments, the rotating container 51 is connected to an oscilloscope. During specific operation, a sawtooth pulse voltage is rapidly applied to the two poles of the rotating container 51 during the later stage of the growth of each mercury drop. A polarogram is obtained within a few seconds, and the fluorescent screen of the oscilloscope is used as a display tool. This allows for rapid recording of the polarogram and facilitates the acquisition of data results.

[0063] In some embodiments, the isolation component 6 includes an isolation plate 61, a vacuum pump 62, and a water inlet pipe 64. The isolation plate 61 serves to insulate against heat and prevent corrosion of the rotating container 51. Simultaneously, since the vacuum pump 62 is located at the outer edge of the isolation plate 61 and is connected to the outside, the vacuum pump 62 can expel the air above the isolation plate 61 from the outer casing 1, thereby preventing oxidation of metal ions upon contact with air. The water inlet pipe 64 is fixedly mounted on the isolation plate 61, with its top connected to a permeable pipe 514 and its bottom connected to the thermal ionization chamber 2. A filter 63 is also provided in the middle of the water inlet pipe 64, which can effectively reduce the amount of sediment entering the rotating container 51.

[0064] Based on the same inventive concept, this technical solution also discloses a detection method, which uses the high-salt food heavy metal detection equipment mentioned above, and includes the following steps:

[0065] 1. Place the sample and electrolyte into the thermal ionization chamber 2, and start the hot blower 9 to blow hot air in, so that the sample decomposes and ionizes in the electrolyte;

[0066] 2. Wait for the solute in the thermal ionization chamber 2 to precipitate, then close the butterfly valve, and the hot blower 9 is started again to send the supernatant suspended in the thermal ionization chamber 2 into the rotating container 51 along the water inlet pipe 64. The rotating container 51 rotates, which in turn drives the stirring component 52 to rotate.

[0067] 3. Pre-electrolysis is performed using anodic stripping voltammetry. After deoxygenation of the test solution, electrolysis is performed at the potential where the metal ions generate the limiting current, i.e., on capillary tube 35, and the metal ions accumulate on electrode plate 32. The mixture is allowed to stand for 30 seconds or 1 minute. The working electrode is then scanned from negative to positive, causing the metal accumulated on the electrode to re-oxidize. The anodic wave and the ratio of peak current height to the measured ion are recorded.

[0068] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A heavy metal detection device for high-salt foods, employing the stripping voltammetry method for measurement, characterized in that... include: The outer casing (1) has a thermal ionization chamber (2) at the bottom, which is filled with electrolyte. One end of the thermal ionization chamber (2) is connected to the air inlet channel (7), which is equipped with a hot blower (9) and has an isolation component (6) in the middle. The electrode cover (3) is screwed to the bottom of the outer casing (1); A stirring device (5), disposed inside the outer casing (1) and connected to the drive motor (4), includes: The rotating container (51) is equipped with a solenoid valve (53) at the bottom and is connected to the thermal ionization chamber (2) through the isolation member (6); A number of stirring components (52) are arranged horizontally along the inner edge of the rotating container (51). When the rotating container (51) rotates, the stirring components (52) rotate synchronously. The other end of the thermal ionization chamber (2) is provided with an air outlet channel (8) and a butterfly valve. When the sample enters the thermal ionization chamber (2), the hot blower (9) blows in hot air to accelerate the decomposition and ionization of the sample. After the sample is completely decomposed, the butterfly valve is closed, allowing the sample solution to enter the rotating container (51). The stirring component (52) includes: The connecting shaft (521) has a stirring rack (522) at its tail end and a bevel gear (523) at its head end. The bevel gear (523) meshes with the ring rack (54) for transmission, and the ring rack (54) is installed inside the outer casing (1); When the rotating container (51) rotates, it drives the bevel gear (523) to rotate, thereby driving the stirring rack (522) to rotate; The outer casing (1) includes: The shell (11) has an inner liner (12) inside, the inner wall of the inner liner (12) is equipped with the annular toothed rack (54), and the bottom is provided with an exhaust hole (14). The motor slot (13) contains a drive motor (4), and its outer edge is connected to the inner liner (12); A central hole (15) is located at the center of the bottom of the inner liner (12); The rotating container (51) includes: The cylinder (511) has a wheel (513) at the top and a water-permeable pipe (514) at the bottom, with a solenoid valve (53) at the end of the water-permeable pipe (514). Assembly holes (512) are numerous and arranged axially along the cylinder (511), and the connecting shaft (521) is inserted inside them. The electrode cap (3) includes: The cap (31) is provided with an electrode disk (32) at the bottom, and a capillary tube (35) is provided at the center of the electrode disk (32). The mercury capsule (33) is equipped with a needle valve (34) inside, which is connected to the capillary tube (35); The spacer (6) includes: An isolation plate (61) is provided with a vacuum pump (62) at its outer edge, and the vacuum pump (62) is connected to the outside. The water inlet pipe (64) is fixedly installed on the isolation plate (61), with its top connected to the water permeable pipe (514) and its bottom connected to the thermo-ionization chamber (2).

2. The heavy metal detection equipment for high-salt foods as described in claim 1, characterized in that, The wheel body (513) is a gear or a pulley.

3. The heavy metal detection equipment for high-salt foods as described in claim 1, characterized in that, The rotating container (51) is connected to the oscilloscope.

4. The heavy metal detection equipment for high-salt foods as described in claim 1, characterized in that, The inner wall of the thermoionization chamber (2) is provided with a heat insulation layer.

5. A detection method, using the high-salt food heavy metal detection equipment as described in claim 1, characterized in that, Includes the following steps:

1. Place the sample and electrolyte into the thermal ionization chamber (2), and start the hot blower (9) to blow hot air in so that the sample decomposes and ionizes in the electrolyte; 2. Wait for the solute in the thermal ionization chamber (2) to precipitate, then close the butterfly valve, and the hot blower (9) is started again to send the supernatant suspended in the thermal ionization chamber (2) into the rotating container (51) along the water inlet pipe (64). The rotating container (51) rotates, and at the same time drives the stirring component (52) to rotate.

3. Pre-electrolysis is performed using the anodic stripping voltammetry method. After the test solution is deoxygenated, the metal ions generate the limiting current at the potential point, which is electrolysis on the capillary tube (35) and accumulate on the electrode plate (32). After standing for 30 seconds or 1 minute, the working electrode is scanned from negative to positive. The metal electrolyzed on the electrode is then re-oxidized. The anodic wave and the ratio of peak current to the measured ion are recorded.

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