Rapid reaction micro-fluidic chip device for food-grade phosphoric acid heavy metal detection

Abstract

The utility model provides a fast reaction microfluidic chip device for food grade phosphoric acid heavy metal detection, and relates to the field of food detection.The fast reaction microfluidic chip device for food grade phosphoric acid heavy metal detection comprises a shell, a microfluidic chip mechanism is installed in the shell, the microfluidic chip mechanism comprises a shell body and a baffle, and the baffle is installed in the shell body. The baffles cooperate with the shell to form a plurality of inclined microfluidic channels, and the microfluidic channels are used for circulating a mixed solution of a sample and a reagent or a developing reagent; according to the rapid reaction micro-fluidic chip device for food-grade phosphoric acid heavy metal detection, heavy metal ions repeatedly flow through an electrode pair area, the heavy metal enrichment amount is rapidly increased, potassium ferrocyanide is added into the container, the rapid reaction with a phosphoric acid solution can be achieved, colored precipitates are generated on the surfaces of the electrodes, and the color of the electrodes is visually changed; the detection time is remarkably shortened, the problem of relatively long detection time is effectively solved, and the on-site rapid detection requirement is met.

Description

Technical Field

[0001] This utility model relates to the field of food testing, specifically a rapid-response microfluidic chip device for the detection of heavy metals in food-grade phosphate. Background Technology

[0002] Food testing refers to a series of analyses and tests conducted on food to ensure it meets relevant safety, quality, and regulatory standards. For example, the detection of heavy metals in food using phosphate is typically performed in liquid form. Specific molecules are modified on the surface of the microreaction channels of a chip. These molecules react with heavy metal ions in the phosphate, forming new compounds that alter certain properties, such as current or color. These changes are detected and analyzed by a detector to obtain information such as the type and concentration of the heavy metal being tested. For instance, some microfluidic chips utilize chemically patterned paper-based analytical devices. Amine, carboxyl, and thiol groups are immobilized on chromatographic paper through condensation reactions and coupled with specific colorimetric reagents. When these reagents come into contact with heavy metal ions, a colorimetric reaction occurs, and the type and content of the heavy metal are determined based on the color change.

[0003] Traditional detection devices typically require food-grade phosphoric acid samples to undergo digestion to convert heavy metals into measurable ionic states. Digestion methods, such as wet digestion, require the use of strong acids and other reagents under heating conditions for extended periods, generally taking several hours or even longer to complete. Furthermore, to improve the accuracy and sensitivity of detection, it is often necessary to separate and enrich the heavy metals in the sample, for example, using solid-phase extraction or liquid-liquid extraction methods. These operations involve numerous steps and require precise control of conditions, resulting in a prolonged overall detection process and making it difficult to meet the needs of rapid on-site detection. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides a rapid-response microfluidic chip device for the detection of heavy metals in food-grade phosphate, solving the problem of long detection time and difficulty in meeting the needs of rapid on-site detection.

[0005] To achieve the above objectives, this utility model is implemented through the following technical solution: a rapid reaction microfluidic chip device for the detection of heavy metals in food-grade phosphate, comprising a housing, wherein a microfluidic chip mechanism is installed inside the housing, the microfluidic chip mechanism comprising a shell and a baffle, the baffle and the shell forming a plurality of inclined microfluidic channels, the microfluidic channels being used to flow a mixed solution of sample and reagent or a colorimetric reagent, and a plurality of electrode pairs for enriching heavy metal ions being installed inside the microfluidic channels, an electric field being formed between the cathode and anode of the electrode pair, in adjacent electrode pairs, the cathode and anode of the electrode pair being arranged alternately, and the cathode side of any electrode pair being opposite to the cathode side of the adjacent electrode pair.

[0006] The outer shell contains a container and a delivery mechanism for introducing liquid from the container into the microfluidic channel. The solution in the microfluidic channel flows back into the container after passing through it, forming a cycle.

[0007] Preferably, the cathode and anode of the electrode pair are both arc-shaped and symmetrically arranged.

[0008] Preferably, the microfluidic channel is equipped with several electrode pairs for enriching heavy metal ions and several guide plates in a figure-eight shape. The guide plates are used to move the liquid toward the cathode of the electrode pair. The guide plates include long plates and short plates, which are arranged alternately.

[0009] Preferably, the outer shell has a slot inside, and the container engages with the slot.

[0010] Preferably, the housing includes a bottom shell, a top shell, and a conveying shell. The top shell has several openings at both ends. The conveying shell is connected to the bottom shell, and the bottom shell and the top shell are fixed together by screws.

[0011] Preferably, the housing is made of insulating material.

[0012] Preferably, a support base is fixedly installed inside the outer shell, and an elastic sheet for supporting the shell is fixedly connected to the upper surface of the support base. The fixed end of the elastic sheet is fixedly connected to the support base, and its free end is fixedly connected to the bottom shell. An electric actuator is fixedly connected to the inner side wall of the base, and a slide rod is fixedly connected to the output end of the electric actuator. The slide rod is slidably connected to the base, and one end of the slide rod is in contact with the free end of the elastic sheet.

[0013] Preferably, the conveying mechanism includes an inlet pipe, a water pump, a water delivery pipe, and a drain pipe connected in sequence. The water pump is fixed to the outer casing. One end of both the drain pipe and the inlet pipe is a flexible hose. One end of each of the several drain pipes is connected to the conveying shell. One end of the water delivery pipe is provided with several water outlets, which are respectively connected to the several drain pipes.

[0014] Compared with existing technologies, this invention has the following advantages: Through the microfluidic channel, the solution circulates within the microfluidic channel and container, allowing heavy metal ions to repeatedly flow through the electrode pair area. Each cycle increases the opportunity for ions to migrate and adsorb towards the arc-shaped cathode, rapidly increasing the enrichment of heavy metals. Compared with single detection, this significantly shortens the enrichment time, improves detection sensitivity, and accelerates the entire detection process, meeting the time requirements for rapid on-site detection. After completing the enrichment and other preliminary work, potassium ferrocyanide is added to the container, which reacts rapidly with the phosphoric acid solution, generating a colored precipitate on the electrode surface. This visually changes the electrode color, allowing for rapid determination of the presence of the corresponding phosphoric acid heavy metal. No complex instruments or lengthy analysis procedures are required; conclusions can be drawn quickly based on a simple colorimetric reaction, significantly shortening the detection time and effectively solving the problem of long detection times, thus meeting the needs of rapid on-site detection. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0016] Figure 2 This is a sectional view of the front view of the outer casing of this utility model;

[0017] Figure 3 This is a schematic diagram of the internal structure of the outer shell of this utility model;

[0018] Figure 4 This is a schematic diagram of the conveying mechanism of this utility model;

[0019] Figure 5 This is an exploded view of a portion of the structure of this utility model;

[0020] Figure 6 This is a sectional view of the top view of the bottom shell of this utility model;

[0021] Figure 7 This utility model Figure 6 Enlarged schematic diagram of the structure at point A in the middle;

[0022] Figure 8 This is a bottom view of the top shell of this utility model.

[0023] The components are: 1. Outer shell; 2. Shell; 201. Bottom shell; 202. Top shell; 203. Conveying shell; 3. Baffle; 4. Microfluidic channel; 5. Electrode pair; 501. Cathode; 502. Anode; 6. Guide plate; 601. Long plate; 602. Short plate; 7. Slot; 8. Elastic sheet; 9. Sliding rod; 10. Container; 11. Conveying mechanism; 110. Inlet pipe; 120. Water delivery pipe; 130. Drain pipe; 12. Opening; 13. Guide triangle plate; 14. Guide arc plate. Detailed Implementation

[0024] like Figures 1-8As shown, a rapid-response microfluidic chip device for the detection of heavy metals in food-grade phosphate includes a housing 1, within which a microfluidic chip mechanism is installed. The microfluidic chip mechanism includes a housing 2 and a baffle 3. The baffle 3, together with the housing 2, forms several inclined microfluidic channels 4. The microfluidic channels 4 are used to flow a mixture of sample and reagent or a colorimetric reagent. Due to the inclined arrangement of the microfluidic channels 4, the liquid can flow towards the outlet of the microfluidic channel 4 by gravity. Several electrode pairs 5 for enriching heavy metal ions are installed within the microfluidic channels 4. An electric field is formed between the cathode 501 and anode 502 of the electrode pair 5. In adjacent electrode pairs 5, the cathode 501 and anode 502 of the electrode pair 5 are arranged alternately. The cathode of any electrode pair 5... The side where 501 is located is opposite to the side where the cathode 501 of the adjacent electrode pair 5 is located. The housing 2 includes a bottom shell 201, a top shell 202, and a conveying shell 203. Both ends of the top shell 202 have several openings 12. The conveying shell 203 is connected to the bottom shell 201. The bottom shell 201 and the top shell 202 are fixed together by screws and are detachable. Several baffles 3 are fixed to the bottom shell 201. The top shell 202 contacts the baffles 3, and the contact part between them is sealed. The housing 2 is made of insulating material. A support base is fixedly installed inside the outer shell 1. An elastic sheet 8 for supporting the housing 2 is fixedly connected to the upper surface of the support base. The fixed end of the elastic sheet 8 is fixedly connected to the support base, and its free end is fixedly connected to the bottom shell 201. An electric push rod is fixedly connected to the inner wall of the base. The output end of the push rod is fixedly connected to a slide rod 9, which is slidably connected to the base. One end of the slide rod 9 contacts the free end of the elastic sheet 8. The cathode 501 and anode 502 of the electrode pair 5 are both arc-shaped and symmetrically arranged. The arc-shaped structure increases the contact area between the electrode and the solution, providing more adsorption sites for heavy metal ions. More adsorption sites mean that heavy metal ions have more opportunities to be adsorbed and are adsorbed more firmly, thereby reducing the probability that the adsorbed heavy metal ions are easily discharged under the action of liquid flow. Several electrode pairs 5 for enriching heavy metal ions and several guide plates 6 in the shape of "eight" are installed in the microfluidic channel 4, which can change the flow direction and path of the liquid in the microfluidic channel 4, causing the liquid to flow towards the cathode 501 of the electrode pair 5. The flow guide plate 6 is used to move the liquid towards the cathode 501 of the electrode pair 5, which facilitates specific liquid transport and distribution, improving the accuracy and efficiency of detection. The flow guide plate 6 includes a long plate 601 and a short plate 602, which are staggered. The flow guide plate 6 causes the liquid to split and merge during the flow process, increasing the turbulence of the liquid, thereby promoting the mixing of the sample and reagent, making the chemical reaction more complete, and improving the detection sensitivity. The delivery mechanism 11 includes an inlet pipe 110, a water pump, a delivery pipe 120, and a drain pipe 130 connected in sequence. The water pump is fixed to the outer shell 1. One end of the drain pipe 130 and the inlet pipe 110 are both set as flexible hoses. One end of each of the drain pipes 130 is connected to the material delivery shell 203.One end of the water supply pipe 120 is equipped with several water outlets, which are respectively connected to several drain pipes 130.

[0025] The outer shell 1 houses a container 10 and a conveying mechanism 11 for introducing the liquid in the container 10 into the microfluidic channel 4. The outer shell 1 has a slot 7 inside, which engages with the container 10. The solution in the microfluidic channel 4 flows back into the container 10 after passing through, forming a circulation. The bottom shell 201 has a guide triangular plate 13 and a guide arc plate 14 fixedly connected inside, so that the solution introduced into the shell 2 from the conveying shell 203 can be guided to several openings 12 and then into several microfluidic channels 4. The guide triangular plate 13 and the guide arc plate 14 have gaps between them and the baffles 3 that are close to them. One side of the top shell 202 is inserted into the gap. The water pump and the water pump are both small in size, and the overall space occupied is small, making it convenient to carry to the food processing site.

[0026] Working principle:

[0027] First, the liquid food sample to be tested is mixed with reagents and transferred into container 10. The mixed reagents include electrolytes and acid-base reagents. Electrolytes, such as potassium chloride or sodium nitrate, are used to enhance conductivity. Electrolytes can increase the conductivity of the solution, making the charge transfer between the electrode and the solution smoother, thereby improving the sensitivity and stability of the detection. Acid-base reagents are used to adjust the pH value. Since food-grade phosphoric acid is a weak acid, its existence is affected by the pH value. During detection, acid-base reagents need to be added to adjust the pH value of the solution so that the phosphoric acid is in a suitable dissociation state for accurate detection. It should be noted that the pH value of the mixed solution needs to be controlled within a certain range, such as pH value controlled within the range of 2-4, so that the electrode has good selectivity and responsiveness to 5-phosphate ions. Buffer solutions can be used to stabilize the pH value, such as acetate-sodium acetate buffer solution or phosphate buffer solution. Container 10 can be removed from the slot 7 for easy addition or removal of solutions.

[0028] Next, one end of the inlet pipe 110 is placed into the container 10, and the water pump is started to make the solution pass through the inlet pipe 110, the water pump, the water delivery pipe 120, several drain pipes 130, the material delivery shell 203, and the shell 2 in sequence. The solution in the shell 2 passes through several openings 12 on one side of the top shell 202 and enters several micro-channels 4 respectively. Then the solution is discharged from the outlet of the micro-channel 4 and passes through another set of openings 12 of the top shell 202, and finally flows back into the container 10, forming a cycle. When the solution flows in the micro-channel 4, under the action of the electric field generated by several electrode pairs 5, heavy metal ions are adsorbed on the arc-shaped cathode 501. This is because heavy metal ions exist in the solution in the form of cations and carry a positive charge. After the cathodes 501 and anodes 502 of several electrode pairs 5 are connected to the power supply, an electric field is formed in the micro-channel 4, such as... Figure 7As shown, the electric field direction points from the anode 502 to the cathode 501. Under the action of the electric field, charged particles will move in a directional manner. When the solution flows, the heavy metal cations in it are acted upon by the electric field force and move towards the cathode 501 along the direction of the electric field lines. Since the electric field force is proportional to the charge of the ions and the electric field strength, the heavy metal ions can overcome the resistance brought by the solution flow and continue to migrate towards the cathode 501. The cathode 501 is arc-shaped, which increases the contact area with the solution and provides more adsorption sites for ions, realizing the adsorption and enrichment of heavy metal ions. The microfluidic channel 4 is inclined with the inclination of the shell 2. The solution in the microfluidic channel 4 uses its own gravity to move along the microfluidic channel 4 towards the outlet of the microfluidic channel 4. The flow direction is controlled by the inclined design of the microfluidic channel 4, which prevents the solution from flowing too fast, allowing heavy metal ions more time to migrate and ensuring thorough mixing. The "V"-shaped structure of the guide plate 6 causes the fluid to split and merge during flow. As the fluid passes through the guide plate 6, it is divided into two or more streams by the V-shaped opening 12, which then merge again downstream. This splitting and merging process increases fluid turbulence, promoting mixing between different fluids and improving the efficiency of the detection process. Because the solution circulates within the microfluidic channel 4 and container 10, the analyte in the solution can continuously... Furthermore, the solution repeatedly flows through the electrode pair 5 region. During each cycle, more heavy metal ions have the opportunity to migrate and adsorb towards the arc cathode 501 under the influence of the electric field generated by the electrode pair 5, continuously increasing the enrichment of heavy metals on the electrode surface and effectively improving detection sensitivity. At the same time, solution circulation promotes uniform mixing of the solution within the microfluidic channel 4, ensuring that the properties of each part of the solution are consistent and reducing detection errors caused by concentration differences. Moreover, continuous circulation can promptly return the reacted solution to the container 10, allowing the reagents in the container 10 to continuously replenish and participate in the reaction, maintaining stable reaction conditions and ensuring the continuity and accuracy of the entire detection process. This facilitates efficient and accurate detection of heavy metals in food phosphoric acid. To lay a solid foundation, it should be noted that in adjacent electrode pairs 5, the cathodes 501 and anodes 502 are arranged alternately, with the side where the cathode 501 of any electrode pair 5 is located opposite to the side where the cathode 501 of the adjacent electrode pair 5 is located. This is because the alternate arrangement of electrode pairs 5 can effectively avoid mutual interference between multiple cathodes 501 and anodes 502. Since the positions of the cathodes 501 and anodes 502 of each electrode pair 5 are relatively independent, and the sides where the cathodes 501 and anodes 502 of adjacent electrode pairs 5 are opposite, the distribution of electric field lines is more regular, reducing electric field disorder and overlap, reducing signal interference between different electrode pairs 5, and facilitating accurate detection of target ion signals.

[0029] Finally, by activating the electric actuator, the slide rod 9 is raised along the base. The top of the slide rod 9 presses against the free end of the elastic sheet 8, which provides support for the bottom shell 201. The fixed end of the elastic sheet 8 is fixed to the base. When the slide rod 9 raises the free end of the elastic sheet 8, the angle between the two ends of the elastic sheet 8 increases, causing the free end of the elastic sheet 8 to tilt more, which in turn increases the tilt of the bottom shell 201 and the microfluidic channel 4. As the tilt of the microfluidic channel 4 increases, the flow rate of the solution inside it can be accelerated. This is because as heavy metal ions migrate, the content of heavy metal ions in the solution begins to decrease, and there is no need to further reduce the solution flow rate. Therefore, the overall detection time can be significantly reduced. To meet the needs of rapid on-site testing, after the above work is completed, other reagents, such as potassium ferrocyanide, are added to container 10. When potassium ferrocyanide is added to a solution containing phosphoric acid, the corresponding heavy metal phosphate on the electrode surface will react to form a colored precipitate, thereby changing the electrode color. Other substances that do not react with it will remain unchanged in color, thus enabling direct detection of food-grade heavy metal phosphate. The top cover can be removed from the bottom cover, allowing testing personnel to directly observe the color change at cathode 501. This intuitive and convenient observation method skips the cumbersome instrument reading and data processing steps, allowing testing personnel to obtain test results in a short time, effectively solving the problem of long testing time and meeting the needs of rapid on-site testing.

[0030] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A rapid-response microfluidic chip device for the detection of heavy metals in food-grade phosphate, comprising a housing (1), characterized in that: The outer shell (1) is equipped with a microfluidic chip mechanism, which includes a shell (2) and a baffle (3). The baffle (3) and the shell (2) form several inclined microfluidic channels (4). The microfluidic channels (4) are used to flow mixed solutions of samples and reagents or colorimetric reagents. Several electrode pairs (5) for enriching heavy metal ions are installed in the microfluidic channels (4). An electric field is formed between the cathode (501) and anode (502) of the electrode pair (5). In adjacent electrode pairs (5), the cathode (501) and anode (502) of the electrode pair (5) are arranged alternately. The side where the cathode (501) of any electrode pair (5) is located is opposite to the side where the cathode (501) of the adjacent electrode pair (5) is located. The outer shell (1) contains a container (10) and a delivery mechanism (11) for introducing the liquid in the container (10) into the microfluidic channel (4). The solution in the microfluidic channel (4) flows back into the container (10) after passing through, forming a cycle.

2. The rapid reaction microfluidic chip device for food-grade heavy metal phosphorus detection according to claim 1, characterized in that: The cathode (501) and anode (502) of the electrode pair (5) are both arc-shaped and symmetrically arranged.

3. The rapid reaction microfluidic chip device for food-grade heavy metal phosphorus detection according to claim 1, characterized in that: The microfluidic channel (4) is equipped with several electrode pairs (5) for enriching heavy metal ions and several guide plates (6) in the shape of the number "eight". The guide plates (6) are used to move the liquid toward the cathode (501) of the electrode pair (5). The guide plates (6) include long plates (601) and short plates (602) and the long plates (601) and short plates (602) are arranged alternately.

4. The rapid reaction microfluidic chip device for food-grade heavy metal phosphorus detection according to claim 1, characterized in that: The outer shell (1) has a slot (7) inside, and the container (10) is engaged with the slot (7).

5. The rapid reaction microfluidic chip device for food-grade heavy metal phosphorus detection according to claim 1, characterized in that: The housing (2) includes a bottom shell (201), a top shell (202) and a conveying shell (203). Both ends of the top shell (202) are provided with several openings (12). The conveying shell (203) is connected to the bottom shell (201). The bottom shell (201) and the top shell (202) are fixed together by screws. Several baffles (3) are fixed to the bottom shell (201). The top shell (202) is in contact with the baffles (3), and the contact part between the two is sealed.

6. The rapid reaction microfluidic chip device for food-grade heavy metal phosphorus detection according to claim 1 or 5, characterized in that: The housing (2) is made of insulating material.

7. A rapid-response microfluidic chip device for detecting heavy metals in food-grade phosphate according to claim 5, characterized in that: A support base is fixedly installed inside the outer shell (1). An elastic sheet (8) for supporting the shell (2) is fixedly connected to the upper surface of the support base. The fixed end of the elastic sheet (8) is fixedly connected to the support base, and its free end is fixedly connected to the bottom shell (201). An electric push rod is fixedly connected to the inner side wall of the base. A slide rod (9) is fixedly connected to the output end of the electric push rod. The slide rod (9) is slidably connected to the base, and one end of it is in contact with the free end of the elastic sheet (8).

8. A rapid reaction microfluidic chip device for detecting heavy metals in food-grade phosphate according to claim 5, characterized in that: The conveying mechanism (11) includes an inlet pipe (110), a water pump, a water delivery pipe (120), and a drain pipe (130) connected in sequence. The water pump is fixed to the outer casing (1). One end of the drain pipe (130) and the inlet pipe (110) are both set as flexible hoses. One end of several drain pipes (130) is connected to the material conveying shell (203). One end of the water delivery pipe (120) is provided with several water outlets, which are respectively connected to several drain pipes (130).

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