A method and system for rapid concentration of a food synthetic colorant extract

Abstract

The application discloses a kind of food synthetic colorant extract liquid quick concentration method and system, belong to food analysis detection field.The method includes the following steps: S1, the extraction liquid to be concentrated is transferred to micro condenser pipe, volume is not more than 1 / 3 of condenser pipe capacity;S2, micro condenser pipe is sealed, ensure system airtightness, carry out horizontal circumferential vortex oscillation;S3, micro condenser pipe is heated, and negative pressure is applied, so that the inside of system is maintained in a precise high vacuum degree environment;S4, when the volume of the extraction liquid is concentrated to the predetermined value, stop concentrating, release the vacuum, take out the micro condenser pipe, after solid-phase extraction purification, dissolve with solvent and filter through microporous filter membrane with needle filter, carry out subsequent detection, solve the problem of low efficiency and high cost in prior art.

Description

Technical Field

[0001] This invention relates to the field of food analysis and testing, and specifically to a rapid concentration method and system for extracts of synthetic food colorants. Background Technology

[0002] In the detection of synthetic colorants in food, as described in GB 5009.35—2023 "National Food Safety Standard - Determination of Synthetic Colorants in Food", the extract obtained after sample extraction usually needs to undergo a concentration step to enrich the target analyte and improve detection sensitivity. The method recommended by this standard is to use a 50°C water bath for nitrogen blowing concentration.

[0003] However, nitrogen blowing concentration has several inherent drawbacks: It is time-consuming: concentrating 10 ml of extract to approximately 3 ml typically takes 70-90 minutes or even longer, becoming a bottleneck in the entire detection process; it is inefficient: nitrogen, as an inert gas, primarily functions to isolate air, rather than providing efficient mass transfer. The driving force for solvent evaporation mainly comes from the static natural evaporation of the liquid surface and a weak nitrogen flow, resulting in low efficiency; it is cumbersome to operate: manual monitoring is required to prevent drying; the nitrogen flow rate and needle tip position need to be optimized, otherwise cross-contamination or loss of the target substance is likely; and it is costly: it consumes a large amount of high-purity nitrogen, leading to high operating costs. Therefore, there is an urgent need in this field to develop a new method that can overcome these drawbacks and achieve rapid, efficient, automated, and low-cost concentration. Summary of the Invention

[0004] To alleviate or partially alleviate the above-mentioned technical problems, the solution of the present invention is as follows:

[0005] A rapid concentration method for food synthetic colorant extract includes the following steps:

[0006] S1. Transfer the extract to be concentrated into a micro-concentration tube, with the volume not exceeding 1 / 3 of the tube's capacity;

[0007] S2. Seal the micro-concentrator tube to ensure the airtightness of the system and perform horizontal circular vortex oscillation;

[0008] S3. Heat the micro-concentration tube and apply negative pressure to maintain a precise high vacuum environment inside the system.

[0009] S4. When the volume of the extract is observed to be concentrated to the predetermined value, stop the concentration, release the vacuum, take out the micro-concentration tube, purify it by solid phase extraction, dissolve it in solvent and filter it through a microporous membrane using a needle filter for subsequent detection.

[0010] By maximizing the surface area of ​​the liquid and continuously renewing the liquid film through vortex oscillation, while the high vacuum significantly reduces the boiling point of the solvent and gentle heating provides energy, the three factors work together to create extremely high solvent evaporation efficiency, reducing the concentration time from 70-90 minutes in the nitrogen blowing method to less than 10 minutes.

[0011] Preferably, the rotational speed of the horizontal circular vortex oscillation in step S2 is 1500 rpm.

[0012] Preferably, the negative pressure in step S3 is controlled at 0.1 bar;

[0013] Preferably, the heating temperature in step S4 is controlled at 50°C.

[0014] This solution also provides a miniature vacuum vortex concentration system for implementing the above method, comprising:

[0015] Vortex oscillation module: used to generate violent horizontal circular vortex motion, increasing the liquid evaporation area, with adjustable speed;

[0016] Heating module: Used for precise heating of samples, with a temperature control range of 25-60℃ and an accuracy of ±1℃;

[0017] Vacuum module: includes a miniature vacuum pump, vacuum chamber, and pressure sensor, used to generate and maintain a high vacuum level within the system;

[0018] Control module: Used to integrate and control the vortex rotation speed, temperature and vacuum level, and can be preset or automatically stopped based on feedback from the solvent sensor.

[0019] The technical solution of this invention has the following beneficial technical effects:

[0020] Extremely fast concentration speed: The surface area of ​​the liquid is maximized and the liquid film is constantly renewed by vortex oscillation. At the same time, the high vacuum significantly reduces the boiling point of the solvent, and gentle heating provides energy. The three factors work together to create extremely high solvent evaporation efficiency, reducing the concentration time from 70-90 minutes of nitrogen blowing to less than 10 minutes.

[0021] High recovery rate and good reproducibility: The vortex motion ensures uniform heating and evaporation of the sample, avoiding the loss of low-boiling-point target substances or degradation of colorants caused by local overheating or airflow impact in the nitrogen blowing method. The sealed environment prevents sample escape and cross-contamination.

[0022] High degree of automation: Automatic programs can be preset according to the sample. Operators only need to load the sample and start the machine. No manual supervision is required. The instrument can automatically complete the concentration process, which greatly saves manpower.

[0023] Low operating cost and environmentally friendly: It does not require the consumption of high-purity nitrogen and only consumes a small amount of electricity, which is in line with the principles of green chemistry.

[0024] Strong parallel processing capability: The device can be designed as a multi-channel system and can be expanded to use multiple vortex oscillation modules to process samples in parallel and synchronously. All samples are processed under completely consistent vortex, temperature and pressure conditions, ensuring excellent parallelism between samples. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the micro vacuum vortex concentration device described in this invention.

[0026] Figure 2 This is a comparison chart of the concentration times of Example 1 and Comparative Example 1 when processing the same extract.

[0027] The components include: 1. Main body of the micro vacuum vortex concentration device; 11. Control digital display panel; 12. Computer connection interface area; 13. Speed ​​control knob; 14. Temperature control knob; 15. Pressure control knob; 16. Gas pressure balance inlet; 17. Vacuum pump extraction port; 18. Gas pressure balance button; 19. Vacuum pump start control button; 2. Vortex oscillation multi-channel sample cell; 21. Micro concentration tube; 3. Multi-channel sample cell sealing cover; 31. Gas path external interface; 32. Piping. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. 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.

[0029] To facilitate a clear description of the technical solutions in the embodiments of the present invention, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order.

[0030] This solution provides a miniature vacuum vortex concentration system, comprising:

[0031] Vortex oscillation module: used to generate violent horizontal circular vortex motion, increasing the liquid evaporation area, with adjustable speed;

[0032] Heating module: Used for precise heating of samples, with a temperature control range of 25-60℃ and an accuracy of ±1℃;

[0033] Vacuum module: includes a miniature vacuum pump, vacuum chamber, and pressure sensor, used to generate and maintain a high vacuum level within the system;

[0034] Control module: Used to integrate and control the vortex rotation speed, temperature and vacuum level, and can be preset or automatically stopped based on feedback from the solvent sensor.

[0035] like Figure 1 As shown, the micro vacuum vortex concentration system includes a micro vacuum vortex concentration device body 1;

[0036] The control module includes a digital display panel 11; a computer connection interface area 12; a speed control knob 13; a temperature control knob 14; and a pressure control knob 15.

[0037] The vacuum module includes a pressure balance inlet 16; a vacuum pump extraction port 17; a pressure balance button 18; a vacuum pump start control button 19; a multi-channel sample cell sealing cover 3; an external gas path interface 31; and a pipeline 32.

[0038] The vortex oscillation module includes a vortex oscillation multi-channel sample cell 2 and a micro-concentration tube 21;

[0039] The concentration process using the aforementioned micro vacuum vortex concentration system is as follows:

[0040] Sample loading: Transfer the extract to be concentrated into the micro-concentration tube 21, with the volume not exceeding 1 / 3 of the capacity of the micro-concentration tube 21.

[0041] Sealing and fixing: The micro-concentration tube 21 is placed in the heating block of the micro vacuum vortex concentration system and tightly connected to the multi-channel sample tank sealing cover 3 of the system to ensure the airtightness of the system.

[0042] Condensation: Start the system and execute the following three operations simultaneously:

[0043] Vortex oscillation: The driving heating block drives the micro-concentration tube 21 to perform a horizontal circular vortex motion at a speed of 1500 rpm.

[0044] Gentle heating: Heat the heating block and control the temperature at 50℃.

[0045] Apply negative pressure: Start the vacuum pump to maintain a precise high vacuum environment inside the system, with the pressure controlled at 0.1 bar.

[0046] End and Collection: The concentration process will be completed within 6 to 10 minutes. When the volume of the extract is observed to be concentrated to the predetermined value, it will be automatically or manually stopped, the vacuum will be released, the concentration tube will be taken out, and after purification by solid phase extraction, it will be concentrated to near dryness, dissolved in solvent and filtered through a microporous membrane using a needle filter for subsequent detection.

[0047] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0048] Example 1

[0049] Using negative pastries as the matrix, the addition levels of tartrazine, sunset yellow, carmine, allura red, brilliant blue and quinoline yellow were all 2.5 mg / kg. The sample preparation procedure was followed, using 10 mL of ethanol-ammonia extract containing tartrazine, sunset yellow, carmine, allura red, brilliant blue and quinoline yellow as an example.

[0050] Transfer 10 mL of the extract into a 30 mL micro-concentration tube 21.

[0051] Place the micro-concentration tube 21 into the heated vortex oscillation multi-channel sample cell 2 of the 25-channel micro vacuum vortex concentration device designed in this invention, and tighten the sealing cover plate 3 of the multi-channel sample cell.

[0052] Parameter settings: Vortex rotation speed 1500 rpm, temperature 50℃, absolute pressure 0.1 bar.

[0053] Start the device; the concentration process begins.

[0054] The device automatically stops and releases the vacuum after 10 minutes when the liquid volume drops to about 3 mL.

[0055] Remove the concentration tube and add 10 mL of 5% methanol aqueous solution in three portions to dissolve the solution as the purification solution. After purification by solid phase extraction, concentrate the solution to near dryness and accurately add 2 mL of ammonium acetate buffer solution with pH 9.0 to dissolve it. Filter the solution through a syringe filter with a filter membrane with a pore size of 0.45 μm. Discard 2 to 5 drops of the initial filtrate and use the subsequent filtrate as the test solution for HPLC analysis.

[0056] Comparative Example 1

[0057] Take 10 mL of the same batch of extract as in Example 1, and concentrate it to about 3 mL by purging with nitrogen in a 50°C water bath according to GB 5009.35-2023 standard for 80 minutes.

[0058] The spiked recoveries and precision of the six synthetic colorants (tartrazine, sunset yellow, carmine, allura red, brilliant blue, and quinoline yellow) in Example 1 are shown in Table 1.

[0059] Table 1

[0060]

[0061] As shown in Table 1, the recoveries of tartrazine, sunset yellow, carmine, allura red, brilliant blue, and quinoline yellow in negative pastry samples ranged from 88.0% to 95.5% at a spiking level of 2.5 mg / kg. The precision of the two determinations of tartrazine, sunset yellow, carmine, allura red, brilliant blue, and quinoline yellow were 1.4%, 0.2%, 1.6%, 1.3%, 1.2%, and 2.9%, respectively, which meet the requirements of GB 5009.35-2023.

[0062] like Figure 2 As shown, in terms of concentration time, Example 1 (10 minutes) was about 88% shorter than Comparative Example 1 (80 minutes).

[0063] The micro-vacuum vortex concentration method provided by this invention can completely replace and is superior to the nitrogen blowing concentration method in the current national standard, providing a revolutionary pretreatment solution for the rapid and accurate detection of synthetic food colorants.

[0064] To better illustrate the present invention, numerous specific details have been provided in the detailed embodiments described above. Those skilled in the art should understand that the present invention can be practiced even without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art have not been described in detail in order to highlight the main points of the present invention.

[0065] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A rapid concentration method for an extract of synthetic food coloring agents, characterized in that, Includes the following steps: S1. Transfer the extract to be concentrated into a micro-concentration tube, with the volume not exceeding 1 / 3 of the tube's capacity; S2. Seal the micro-concentrator tube to ensure the airtightness of the system and perform horizontal circular vortex oscillation; S3. Heat the micro-concentration tube and apply negative pressure to maintain a precise high vacuum environment inside the system. S4. When the volume of the extract is observed to be concentrated to the predetermined value, stop the concentration, release the vacuum, take out the micro-concentration tube, purify it by solid phase extraction, dissolve it in solvent and filter it through a microporous membrane using a needle filter for subsequent detection.

2. The rapid concentration method for a food synthetic colorant extract according to claim 1, characterized in that, The rotational speed of the horizontal circular vortex oscillation in step S2 is 1500 rpm.

3. The rapid concentration method for a food synthetic colorant extract according to claim 1, characterized in that, The negative pressure in step S3 is controlled at 0.1 bar.

4. The rapid concentration method for a food synthetic colorant extract according to claim 1, characterized in that, The heating temperature in step S4 is controlled at 50°C.

5. A miniature vacuum vortex concentration system for implementing the method according to any one of claims 1-4, characterized in that, include: Vortex oscillation module: used to generate violent horizontal circular vortex motion, increasing the liquid evaporation area, with adjustable speed; Heating module: Used for precise heating of samples, with a temperature control range of 25-60℃ and an accuracy of ±1℃; Vacuum module: includes a miniature vacuum pump, vacuum chamber, and pressure sensor, used to generate and maintain a high vacuum level within the system; Control module: Used to integrate and control the vortex rotation speed, temperature and vacuum level, and can be preset or automatically stopped based on feedback from the solvent sensor.

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