Food additive and heavy metal element combined detector based on enzyme-linked immunosorbent assay and application thereof

Abstract

The invention relates to the technical field of food detection, in particular to a food additive and heavy metal element combined detector based on enzyme-linked immunosorbent assay and application thereof.The food additive and heavy metal element combined detector comprises a sample processing assembly and an enzyme-labeled detection assembly which is arranged on the outer wall of the sample processing assembly and detects a sample through enzyme-linked immunosorbent assay; the sample processing assembly comprises a processing bin, a transportation mechanism arranged in the processing bin and two sets of extraction mechanisms arranged above the transportation mechanism. According to the invention, the electric heating coil and the ultrasonic oscillator are arranged in the treatment bin side by side, and the transportation mechanism is combined to accurately position and move the two test tubes, so that ultrasonic extraction and high-temperature closed digestion can be automatically and parallelly completed, the detection efficiency is improved, physical isolation is carried out through the sealing part, cross contamination is effectively avoided, and the detection accuracy is improved. And a reliable basis is provided for subsequent detection.

Description

Technical Field

[0001] This invention relates to the field of food testing technology, and more specifically, to a combined detector for food additives and heavy metals based on enzyme-linked immunosorbent assay (ELISA) and its application. Background Technology

[0002] This combined detection technology based on enzyme-linked immunosorbent assay (ELISA) allows for the simultaneous screening of food additives and trace heavy metals in a single analysis by designing specific antibodies. The method competitively binds the target analyte to the enzyme-labeled antigen, utilizing an enzyme-catalyzed colorimetric reaction for quantitative detection. It combines high sensitivity and high throughput, thus improving detection efficiency.

[0003] Patent application CN201720820696.1 discloses a food safety monitoring device, including a main body comprising a spectrophotometer, an enzyme-linked immunosorbent assay (ELISA) reader, and a quantitative PCR instrument. The spectrophotometer includes a light source, a laser monochromator, a sample chamber, an emission monochromator, and a detector. The ELISA reader is mounted on the right end of the spectrophotometer. This food safety monitoring device is simple to use, rationally combining the spectrophotometer, ELISA reader, and quantitative PCR instrument. It can detect multiple harmful substances, shorten the detection cycle, improve detection efficiency, and is highly practical.

[0004] However, in existing technologies, when dealing with two types of target substances—food additives and heavy metals—which have vastly different physicochemical properties, the pretreatment processes for these two types of target substances differ significantly in principle, equipment, and conditions. Existing devices often require step-by-step, manual, or discrete equipment operations, resulting in lengthy detection processes. Furthermore, manual operation easily introduces cross-contamination between steps. Secondly, key steps from adding reagents to transferring the test solution largely rely on manual labor, which not only makes it difficult to guarantee the accuracy and repeatability of liquid transfer but also exposes operators directly to hazardous chemicals, posing a high safety risk. This severely restricts its application in rapid, safe, and high-throughput joint detection in the field.

[0005] In view of this, we propose a joint detector for food additives and heavy metal elements based on enzyme-linked immunosorbent assay (ELISA) and its application. Summary of the Invention

[0006] The purpose of this invention is to provide a food additive and heavy metal element combined detector based on enzyme-linked immunosorbent assay (ELISA) and its application. By using an electric heating coil and an ultrasonic oscillator placed side by side in the processing chamber, combined with the precise positioning and movement of two test tubes by a transport mechanism, ultrasonic extraction and high-temperature sealed digestion can be completed automatically and in parallel, thereby solving the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A food additive and heavy metal element combined detector based on enzyme-linked immunosorbent assay (ELISA) includes an enzyme labeling detection component and a sample processing component for delivering ELISA detection samples to it. The sample processing assembly includes a processing chamber, a transport mechanism disposed inside the processing chamber, and two extraction mechanisms disposed above the transport mechanism. The processing chamber is equipped with an electric heating coil and an ultrasonic oscillator; The transport mechanism includes a fixed frame that can slide at a fixed distance within the processing chamber, a placement plate set above the fixed frame for placing test tubes, a pair of sealing parts that slide on the top surface of the placement plate, and a multi-section electric push rod set inside the fixed frame. The outer walls at both ends of the fixed frame are provided with two pairs of inclined grooves. The sealing part includes a pair of sealing plates and a pair of protruding rods set below one end of the sealing plates. The pair of protruding rods are slidably engaged with the pair of inclined grooves at the front and rear. After the multi-section electric push rod drives the placement plate and test tube to move down synchronously, the protruding rod can move along the inclined groove trajectory, drive the sealing plate to extend outward and seal the top of the test tube, and perform high-temperature digestion and ultrasonic extraction on the test tube through the electric heating coil and ultrasonic oscillator respectively.

[0008] In the technical solution of the present invention, the processing chamber further includes a chamber body, two guide rails fixedly connected to the groove in the center of the bottom surface of the chamber body by bolts, a partition plate welded to the inner wall of the chamber body near the top, and a cover plate snapped and fixed to the top surface of the chamber body. The outer shell of the enzyme labeling detection component is welded and fixed to the chamber body.

[0009] In the technical solution of the present invention, through slots are provided on the outer walls of both the left and right ends of the chamber body, the electric heating coil and the ultrasonic oscillator are fixedly connected to the bottom surface inside the chamber body by bolts and located on the outside of the guide rail, the partition is provided with slots on the outer walls of both the left and right ends, and the chamber body is hinged to the outside of the through slots with a chamber door.

[0010] In the above setup, the chamber body, guide rails, partitions, and cover plate constitute a robust and partitioned processing chamber. The heating coil and ultrasonic oscillator are separately housed within, providing independent and parallel physical reaction spaces for the subsequent high-temperature digestion and ultrasonic extraction of samples from the two test tubes, forming the fundamental structure for joint detection.

[0011] In the technical solution of the present invention, the transportation mechanism further includes a motor fixedly connected to the outer wall of the cargo box by bolts, a first lead screw coaxially connected to the output shaft of the motor, and a slide table threaded to the outside of the first lead screw and slidably connected to the top surface of the two guide rails. The rear end of the first lead screw is rotatably connected to the inner wall of the groove at the center of the bottom surface inside the cargo box.

[0012] In the technical solution of the present invention, the fixed frame is fixedly connected to the top surface of the slide by screws, two inclined grooves on the same side of the outer wall of the fixed frame are symmetrically distributed, the top of the inclined grooves are connected to the top surface of the fixed frame, and a telescopic frame is slidably connected inside the fixed frame.

[0013] In the technical solution of the present invention, the placement plate is snapped and fixed on the top surface of the telescopic frame. Two parallel sliding grooves are provided on the top surface of the placement plate, and a placement hole for placing test tubes is provided at the end. The multi-section electric push rod is fixedly connected to the top surface of the slide table by screws, and the top end of its telescopic rod is fixedly connected to the bottom surface of the placement plate.

[0014] In the above setup, the motor, the first lead screw, and the slide drive the fixed frame and the placement plate to move horizontally; multiple electric push rods control its vertical lifting and lowering. The cooperation of the inclined groove and the convex rod transforms the downward movement into a sealing plate sealing the test tube, realizing the automatic positioning of the test tube between the transportation, liquid addition, processing, and sampling stations.

[0015] In the technical solution of the present invention, the sealing part further includes a slide rod integrally formed on the bottom surface of the sealing plate and slidably connected to the inside of the slide groove, and a limiting block snapped and fixed to the outer wall of the slide rod. The part of the slide rod that contacts the slide groove is provided with damping to provide sliding resistance and ensure that the sealing plate remains stable in the non-operating state. The protruding rod is threadedly connected to the bottom end of the slide rod and the end extends into the inside of the inclined groove.

[0016] In the above configuration, the sliding rod of the sealing part slides within the groove, and the protruding rod at its bottom end is constrained by the inclined groove of the fixed frame. This design utilizes vertical motion to drive the sealing plate to close horizontally, achieving reliable sealing and opening of the reaction space of the two test tubes with a single power source, ensuring the safety and contamination prevention of the processing.

[0017] In the technical solution of the present invention, the extraction mechanism includes a motor fixedly connected to the top surface of the partition by screws, a main bevel gear sleeved at the end of the motor output shaft, a secondary bevel gear vertically meshing with the bottom side of the main bevel gear, a second lead screw sleeved in the inner hole of the secondary bevel gear and rotatably connected to the inside of the partition, and a lifting plate threaded to the outside of the second lead screw. The lifting plate is located above the partition and limit ring grooves are formed at both ends of the lifting plate.

[0018] In the technical solution of the present invention, the extraction mechanism further includes a pair of slide rods that are snapped and fixed between the top surface of the chamber and the top surface of the partition, a syringe that is snapped and fixed in the insertion port of the outer wall of the partition, and a piston rod that is slidably connected inside the syringe. The top end of the piston rod is snapped and fixed inside the end limiting ring groove of the lifting plate.

[0019] In the above setup, the extraction mechanism controls the lifting plate to move the piston rod inside the syringe. This enables precise dispensing of reagents such as organic solvents and digesting acids, as well as accurate extraction and transfer of the supernatant and digestion solution after treatment, completing an automated closed-loop liquid handling system.

[0020] On the other hand, the present invention also provides an application of a food additive and heavy metal element co-detector based on enzyme-linked immunosorbent assay (ELISA), which is the application of the aforementioned food additive and heavy metal element co-detector based on ELISA in food safety testing.

[0021] Compared with the prior art, the beneficial effects of the present invention are: 1. This enzyme-linked immunosorbent assay (ELISA)-based detector for food additives and heavy metals and its application utilizes a combination of a heating coil and an ultrasonic oscillator placed side-by-side within the processing chamber, along with a transport mechanism for precise positioning and movement of two test tubes. This allows ultrasonic extraction and high-temperature sealed digestion to be completed automatically and in parallel, improving detection efficiency. Furthermore, the physical isolation provided by the sealing section effectively avoids cross-contamination, providing a reliable foundation for subsequent detection.

[0022] 2. This enzyme-linked immunosorbent assay (ELISA)-based detector for food additives and heavy metals and its application precisely execute the tasks of "reagent dispensing" and "sample extraction" through two sets of extraction mechanisms, completely eliminating human error and ensuring the accuracy and repeatability of the test results. At the same time, it significantly reduces the risk of operators coming into contact with hazardous reagents and improves the safety and ease of use of the equipment. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a cross-sectional view of the overall structure of the present invention; Figure 3 This is a cross-sectional schematic diagram of the processing chamber in this invention; Figure 4 This is a schematic diagram of the transportation mechanism in this invention; Figure 5 This is a partial structural diagram of the transportation mechanism in this invention; Figure 6 This is a schematic diagram of the structure of the placement plate in this invention; Figure 7 This is a schematic diagram of the sealing part in this invention; Figure 8 This is a schematic diagram of the extraction mechanism in this invention; Figure 9 This is a partial structural schematic diagram of the extraction mechanism in this invention; Figure 10 This is a schematic diagram of the lifting plate in this invention; Explanation of reference numerals in the attached figures: 100. Sample processing assembly; 110. Processing chamber; 111. Chamber body; 1110. Through groove; 112. Guide rail; 113. Heating coil; 114. Ultrasonic oscillator; 115. Partition; 1150. Insert; 116. Chamber door; 117. Cover plate; 120. Transport mechanism; 121. Motor; 122. First lead screw; 123. Slide table; 124. Fixing frame; 1240. Inclined groove; 125. Telescopic frame; 126. Placement plate; 127. 0. Slide groove; 1261. Placement hole; 127. Test tube; 128. Sealing part; 1280. Sealing plate; 1281. Slide bar; 1282. Limiting block; 1283. Protruding rod; 129. Multi-section electric actuator; 130. Extraction mechanism; 131. Motor; 132. Main bevel gear; 133. Secondary bevel gear; 134. Second lead screw; 135. Lifting plate; 1350. Limiting ring groove; 136. Slide bar; 137. Syringe; 138. Piston rod; 200. Enzyme-labeled detection kit. Detailed Implementation

[0024] The technical solutions of this invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0025] Please see Figures 1-3 As shown, this embodiment provides the following technical solution: The application of a food additive and heavy metal element combined detector based on enzyme-linked immunosorbent assay (ELISA) in food safety testing includes an enzyme-linked immunosorbent assay (ELISA) detection component 200 and a sample processing component 100 for delivering ELISA detection samples to it. The ELISA detection module 200 is an integrated, small-scale ELISA reader, primarily comprising a multi-wavelength light source system, a precision filter wheel, a 96-well microplate stage, a high-sensitivity photodetector, and an embedded data processing unit. Its detection principle is based on the classic enzyme-linked immunosorbent assay (ELISA): the test solution (i.e., the enzyme-labeled complex already bound to the target analyte) prepared by the sample processing module 100 and added to the reaction wells of the microplate, after the addition of the chromogenic substrate, the enzyme bound to the solid phase within the wells catalyzes a colorimetric reaction. The light source of the ELISA detection module 200 emits a specific wavelength beam that passes perpendicularly through the liquid in the reaction wells of the microplate; the photodetector measures the intensity of the transmitted light and converts it into an absorbance value. Higher analyte concentrations result in less enzyme bound to the solid phase, a lighter color, and a lower absorbance value. The built-in processor automatically converts the absorbance value into the specific concentration of food additives or heavy metals in the sample based on a pre-stored standard curve, thus completing the quantitative detection. This is existing technology and will not be elaborated further.

[0026] Specifically, the sample processing assembly 100 includes a processing chamber 110, a transport mechanism 120 disposed inside the processing chamber 110, and two extraction mechanisms 130 disposed above the transport mechanism 120.

[0027] Furthermore, the processing chamber 110 includes a chamber body 111, two guide rails 112 that are fixedly connected to the groove in the center of the bottom surface of the chamber body 111 by bolts, an electric heating coil 113, an ultrasonic oscillator 114, a partition 115 welded to the inner wall of the chamber body 111 near the top, and a cover plate 117 snapped and fixed to the top surface of the chamber body 111. The outer shell of the enzyme labeling detection component 200 is welded and fixed to the chamber body 111.

[0028] Furthermore, through slots 1110 are provided on the outer walls of both the left and right ends of the compartment 111. The heating coil 113 and the ultrasonic oscillator 114 are both fixedly connected to the bottom surface inside the compartment 111 by bolts and are located on the outside of the guide rail 112. Inserts 1150 are provided on the outer walls of both the left and right ends of the partition 115. A compartment door 116 is hinged to the outside of the through slots 1110 of the compartment 111. Furthermore, the chamber 111 is used to ensure the overall structural strength of the processing chamber 110, the chamber door 116 on the outside of the through slot 1110 is used to facilitate technicians to operate inside the chamber 111, the guide rail 112 is used to provide a transport section for the structure in the transport mechanism 120, the electric heating coil 113 and the ultrasonic oscillator 114 respectively perform high-temperature digestion and ultrasonic extraction of sample reagents, the partition 115 is used to separate the internal space of the chamber 111, the socket 1150 is used to provide a fixed space for the structure in the extraction mechanism 130, and the cover plate 117 is used by operators to inspect and maintain the structure in the extraction mechanism 130; In the above configuration, the chamber 111, guide rail 112, partition 115, and cover 117 constitute the robust and partitionable main body of the processing chamber 110. The heating coil 113 and ultrasonic oscillator 114 are placed separately within it, providing independent and parallel physical reaction spaces for subsequent high-temperature digestion and ultrasonic extraction of samples in the two test tubes 127, which is the basic structure for achieving joint detection.

[0029] Please see Figures 4-6 As shown, in this embodiment, the transport mechanism 120 includes a fixed frame 124 that can slide at a fixed distance within the processing chamber 110, a placement plate 126 disposed above the fixed frame 124 for placing test tubes 127, a pair of sealing parts 128 that slide on the top surface of the placement plate 126, and a multi-section electric push rod 129 disposed inside the fixed frame 124. Two pairs of inclined grooves 1240 are formed on the outer walls at both ends of the fixed frame 124. The sealing part 128 includes a pair of sealing plates 1280 and a pair of protruding rods 1283 disposed below one end of the sealing plates 1280. The pair of protruding rods 1283 are slidably engaged with the pair of inclined grooves 1240 at the front and rear. After the multi-section electric push rods 129 drive the placement plate 126 and test tubes 127 to move downwards synchronously, the protruding rods 1283 can move along the trajectory of the inclined grooves 1240, causing the sealing plates 1280 to extend outwards and seal the top of the test tubes 127.

[0030] Specifically, when the placement plate 126 moves with the fixing frame 124 to below the extraction mechanism 130, the two extraction mechanisms 130 can respectively inject and extract liquid from the test tube 127.

[0031] Furthermore, the transport mechanism 120 also includes a motor 121 bolted to the outer wall of the compartment 111, a first lead screw 122 coaxially connected to the output shaft of the motor 121, and a slide 123 threaded to the outside of the first lead screw 122 and slidably connected to the top surface of the two guide rails 112. The rear end of the first lead screw 122 is rotatably connected to the inner wall of the groove at the center of the bottom surface inside the compartment 111.

[0032] Furthermore, the fixed frame 124 is fixedly connected to the top surface of the slide table 123 by screws. Two inclined grooves 1240 on the same side of the outer wall of the fixed frame 124 are symmetrically distributed. The top of the inclined grooves 1240 is connected to the top surface of the fixed frame 124. A telescopic frame 125 is slidably connected inside the fixed frame 124.

[0033] Furthermore, the placement plate 126 is snapped and fixed to the top surface of the telescopic frame 125. The top surface of the placement plate 126 has two parallel sliding grooves 1260 and the end has a placement hole 1261 for placing test tubes 127. The multi-section electric push rod 129 is fixedly connected to the top surface of the slide table 123 by screws, and the top end of its telescopic rod is fixedly connected to the bottom surface of the placement plate 126.

[0034] Furthermore, before sample processing, the operator divides the same homogenized food sample into two identical test tubes 127 in equal portions. The two test tubes 127 are then placed into placement holes 1261 on the placement plate 126 of the transport mechanism 120. Subsequently, the motor 121 drives the first lead screw 122, causing the slide table 123 and the fixed frame 124 to move horizontally, thereby transporting the telescopic frame 125 and the placement plate 126 carrying the test tubes 127 within the processing chamber 110. The groove on the placement plate 126 restricts the movement range of the sealing part 128, and the activation of the multi-section electric push rod 129 adjusts the height of the placement plate 126.

[0035] In the above configuration, motor 121, first lead screw 122, and slide table 123 drive the fixed frame 124 and placement plate 126 to move horizontally; multi-section electric push rod 129 controls its vertical lifting. The cooperation between inclined groove 1240 and protruding rod 1283 transforms the downward movement into the sealing of test tube 127 by sealing plate 1280, realizing the automatic positioning of test tubes between transportation, liquid addition, processing, and sampling stations.

[0036] Please see Figure 7 As shown, in this embodiment, the sealing part 128 further includes a slide bar 1281 integrally formed on the bottom surface of the sealing plate 1280 and slidably connected to the inside of the slide groove 1260, and a limiting block 1282 snapped and fixed to the outer wall of the slide bar 1281. The part of the slide bar 1281 that contacts the slide groove 1260 is provided with damping to provide sliding resistance and ensure that the sealing plate 1280 remains stable in the non-operating state. The protruding rod 1283 is threaded to the bottom end of the slide bar 1281 and the end extends into the inside of the inclined groove 1240.

[0037] Furthermore, the multi-section electric actuator 129 is activated, causing the placement plate 126 and the two test tubes 127 to move down synchronously. During the downward movement, the protruding rod 1283 of the sealing part 128 moves along the inclined groove 1240 on the fixed frame 124, pushing the sealing plate 1280 to extend outward, sealing the top of the two test tubes 127 and forming an independent sealed reaction space.

[0038] In the above configuration, the slide bar 1281 of the sealing part 128 slides within the groove 1260, and the protruding rod 1283 at its bottom end is constrained by the inclined groove 1240 of the fixed frame. This design utilizes vertical motion to drive the sealing plate 1280 to close horizontally, achieving reliable sealing and opening of the reaction space of the two test tubes 127 with a single power source, ensuring the safety and pollution prevention of the processing.

[0039] Please see Figures 8-10As shown, in this embodiment, the extraction mechanism 130 includes a motor 131 fixedly connected to the top surface of the partition 115 by screws, a main bevel gear 132 sleeved at the end of the output shaft of the motor 131, a secondary bevel gear 133 vertically meshing with the bottom side of the main bevel gear 132, a second lead screw 134 sleeved in the inner hole of the secondary bevel gear 133 and rotatably connected to the inside of the partition 115, and a lifting plate 135 threadedly connected to the outside of the second lead screw 134. The lifting plate 135 is located above the partition 115 and both ends of the lifting plate 135 are provided with limit ring grooves 1350.

[0040] Specifically, the extraction mechanism 130 also includes a pair of slide rods 136 that are snapped and fixed between the top surface of the chamber 111 and the top surface of the partition 115, a syringe 137 that is snapped and fixed in the insertion port 1150 on the outer wall of the partition 115, and a piston rod 138 that is slidably connected inside the syringe 137. The top end of the piston rod 138 is snapped and fixed inside the end limiting annular groove 1350 of the lifting plate 135.

[0041] Furthermore, after the test tube 127 is positioned below the extraction mechanism 130 located at the rear, the motor 131 drives the piston rod 138 to move, controlling the two syringes 137 to inject the organic extraction solvent into the first test tube 127 and inject a mixture of nitric acid and hydrogen peroxide into the second test tube 127.

[0042] Furthermore, after the transport mechanism 120 horizontally moves the placement plate 126 to a position below the extraction mechanism 130 located at the front, the extraction mechanism 130 at the front is activated: For the first test tube 127, the syringe 137 is precisely inserted into the upper layer of the liquid surface to extract a quantitative amount of clear supernatant as the test solution A. For the second test tube 127, the syringe 137 extracts a quantitative amount of cooled digestion solution as the test solution B.

[0043] In the above configuration, the extraction mechanism 130 controls the lifting plate 135 to drive the piston rod 138 to move within the syringe 137. This achieves precise dispensing of reagents such as organic solvents and digesting acids, as well as precise extraction and transfer of the supernatant and digestion solution after treatment, completing an automated closed-loop liquid handling system.

[0044] Finally, it should be noted that the heating coil 113, ultrasonic oscillator 114, motor 121, multi-section electric actuator 129, and motor 131 involved in this invention are all general standard parts or components known to those skilled in the art. Their structures and principles can be learned by those skilled in the art through technical manuals or conventional experimental methods. In the idle parts of this device, the heating coil 113, ultrasonic oscillator 114, motor 121, multi-section electric actuator 129, and motor 131 are connected to an external power source through wires. The specific connection method should refer to the working principle in this invention. The electrical connections between the various electrical components are completed in the order of their operation. The detailed connection methods are all technologies known in the art.

[0045] When using the enzyme-linked immunosorbent assay (ELISA)-based joint detector for food additives and heavy metals of this invention, the first step is to place and initially locate the sample: The operator divides the same homogenized food sample into two identical test tubes 127. The two test tubes 127 are then placed into the placement holes 1261 on the placement plate 126 of the transport mechanism 120. The organic extraction solvent for food additive detection and the mixture of nitric acid and hydrogen peroxide for heavy metal detection are placed into the two syringes 137 in the extraction mechanism 130 located at the rear. After closing the chamber door 116, the equipment is started. The motor 121 drives the first lead screw 122, causing the slide table 123 and the fixed frame 124 to move horizontally, transporting the placement plate 126 carrying the test tubes 127 to the processing chamber 110, corresponding to the position below the extraction mechanism 130 located at the rear.

[0046] Next, the reagents for the differentiated process are added automatically: Once test tube 127 is accurately positioned, the extraction mechanism 130 located at the rear is activated. Motor 131 drives piston rod 138 to move, controlling the two syringes 137 to inject organic extraction solvent into the first test tube 127 and inject a mixture of nitric acid and hydrogen peroxide into the second test tube 127. After the injection is completed, the extraction mechanism 130 resets.

[0047] Then, parallel differential preprocessing begins: After the reagents are added, the transport mechanism 120 moves the placement plate 126 horizontally to the processing station in the middle of the processing chamber 110. The multi-section electric actuator 129 is activated, causing the placement plate 126 and the two test tubes 127 to move downwards simultaneously. During this downward movement, the protruding rod 1283 of the sealing part 128 moves along the inclined groove 1240 on the fixed frame 124, pushing the sealing plate 1280 outwards to seal the tops of the two test tubes 127, forming an independent, sealed reaction space. After sealing, the system simultaneously starts two processing procedures: For the first test tube 127: Start the ultrasonic oscillator 114 to perform ultrasonic extraction on the sample in the test tube 127. Then let the system stand to allow the solution to separate into layers, which will facilitate the subsequent extraction of the supernatant.

[0048] For the second test tube 127: the heating coil 113 is activated to perform high-temperature digestion on test tube 127. After the digestion process is completed, the system automatically enters the cooling stage.

[0049] Then, the processing solution is automatically extracted and transferred for sample loading: After both test tubes 127 have been processed, the multi-section electric push rod 129 rises, opening the seal of the test tubes 127. The transport mechanism 120 moves the placement plate 126 horizontally to the position below the extraction mechanism 130 located at the front. The extraction mechanism 130 located at the front is activated: For the first test tube 127, the syringe 137 is precisely inserted into the upper layer of the liquid surface to extract a quantitative amount of clear supernatant as the test solution A.

[0050] For the second test tube 127, syringe 137 draws a fixed amount of cooled digestion solution as the test solution B.

[0051] The subsequent transport mechanism 120 will place the plate 126 at the initial work station. The operator opens the door 116 and uses the extraction mechanism 130 located at the front to add the test solution A and test solution B from the two syringes 137 into the corresponding pre-coated reaction wells of the microplate in the enzyme-labeled detection component 200 in a quantitative manner.

[0052] Finally, automated immunoassay analysis and result output are performed: After sample addition, the microplate is transferred to a constant-temperature incubation chamber for enzyme-linked immunosorbent assay (ELISA) incubation. After the reaction, the microplate is then sent to the ELISA detection unit 200 for optical scanning and absorbance measurement. The built-in processor automatically calculates the concentration based on pre-stored standard curves for different target substances and finally outputs a joint detection report of "food additive content" and "heavy metal content" simultaneously on the integrated display screen.

[0053] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the specification and its equivalents.

Claims

1. A combined detector for food additives and heavy metal elements based on enzyme-linked immunosorbent assay (ELISA), characterized in that: It includes an enzyme-labeled detection component and a sample processing component that delivers enzyme-linked immunosorbent assay (ELISA) samples to it; The sample processing assembly includes a processing chamber, a transport mechanism disposed inside the processing chamber, and two extraction mechanisms disposed above the transport mechanism. The processing chamber is equipped with an electric heating coil and an ultrasonic oscillator; The transport mechanism includes a fixed frame that can slide at a fixed distance within the processing chamber, a placement plate set above the fixed frame for placing test tubes, a pair of sealing parts that slide on the top surface of the placement plate, and a multi-section electric push rod set inside the fixed frame. The outer walls at both ends of the fixed frame are provided with two pairs of inclined grooves. The sealing part includes a pair of sealing plates and a pair of protruding rods set below one end of the sealing plates. The pair of protruding rods are slidably engaged with the pair of inclined grooves at the front and rear. After the multi-section electric push rod drives the placement plate and the test tube to move down synchronously, the protruding rod can move along the inclined groove trajectory, drive the sealing plate to extend outward and seal the top of the test tube, and perform high-temperature digestion and ultrasonic extraction on the test tube by electric heating coil and ultrasonic oscillator respectively. When the placement plate moves with the fixed frame to below the extraction mechanism, the two extraction mechanisms respectively inject and extract liquid from the test tube.

2. The combined detector for food additives and heavy metal elements based on enzyme-linked immunosorbent assay (ELISA) according to claim 1, characterized in that: The processing chamber also includes a chamber body, two guide rails fixedly connected to the groove in the center of the bottom surface inside the chamber body by bolts, a partition plate welded to the inner wall of the chamber body near the top, and a cover plate snapped and fixed to the top surface of the chamber body. The outer shell of the enzyme labeling detection component is welded and fixed to the chamber body.

3. The combined detector for food additives and heavy metal elements based on enzyme-linked immunosorbent assay (ELISA) according to claim 2, characterized in that: The outer walls at both ends of the chamber are provided with through slots. The heating coil and the ultrasonic oscillator are both fixedly connected to the bottom surface inside the chamber by bolts and located outside the guide rail. The outer walls at both ends of the partition are provided with slots. The chamber is hinged to the outside of the through slots with a chamber door.

4. The combined detector for food additives and heavy metal elements based on enzyme-linked immunosorbent assay (ELISA) according to claim 3, characterized in that: The transport mechanism also includes a motor fixed to the outer wall of the cargo compartment by bolts, a first lead screw coaxially connected to the output shaft of the motor, and a slide table threaded to the outside of the first lead screw and slidably connected to the top surface of the two guide rails. The rear end of the first lead screw is rotatably connected to the inner wall of the groove at the center of the bottom surface inside the cargo compartment.

5. The combined detector for food additives and heavy metal elements based on enzyme-linked immunosorbent assay (ELISA) according to claim 4, characterized in that: The fixed frame is fixedly connected to the top surface of the slide table by screws. Two inclined grooves on the same side of the outer wall of the fixed frame are symmetrically distributed. The top of the inclined grooves is connected to the top surface of the fixed frame. A telescopic frame is slidably connected inside the fixed frame.

6. The combined detector for food additives and heavy metal elements based on enzyme-linked immunosorbent assay (ELISA) according to claim 5, characterized in that: The placement plate is snapped and fixed to the top surface of the telescopic frame. Two parallel sliding grooves are provided on the top surface of the placement plate, and a placement hole for placing test tubes is provided at the end. The multi-section electric push rod is fixedly connected to the top surface of the slide table by screws, and the top end of its telescopic rod is fixedly connected to the bottom surface of the placement plate.

7. The combined detector for food additives and heavy metal elements based on enzyme-linked immunosorbent assay (ELISA) according to claim 6, characterized in that: The sealing part also includes a slide bar integrally formed on the bottom surface of the sealing plate and slidably connected inside the slide groove, and a limiting block snapped and fixed to the outer wall of the slide bar. The part of the slide bar that contacts the slide groove is provided with damping to provide sliding resistance and ensure that the sealing plate remains stable in the non-operating state. The protruding rod is threadedly connected to the bottom end of the slide bar and the end extends into the interior of the inclined groove.

8. The combined detector for food additives and heavy metals based on enzyme-linked immunosorbent assay (ELISA) according to claim 7, characterized in that: The extraction mechanism includes a motor fixedly connected to the top surface of the partition by screws, a main bevel gear sleeved at the end of the motor output shaft, a secondary bevel gear vertically meshing with the bottom side of the main bevel gear, a second lead screw sleeved in the inner hole of the secondary bevel gear and rotatably connected inside the partition, and a lifting plate threaded to the outside of the second lead screw. The lifting plate is located above the partition and has limit ring grooves at both ends.

9. The combined detector for food additives and heavy metal elements based on enzyme-linked immunosorbent assay (ELISA) according to claim 8, characterized in that: The extraction mechanism also includes a pair of slide rods that are snapped and fixed between the top surface of the chamber and the top surface of the partition, a syringe that is snapped and fixed in the insertion port on the outer wall of the partition, and a piston rod that is slidably connected inside the syringe. The top end of the piston rod is snapped and fixed inside the end limiting ring groove of the lifting plate.

10. The application of a combined detector for food additives and heavy metals based on enzyme-linked immunosorbent assay (ELISA), as described in claim 9, is characterized in that: It is used in food safety testing.

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