Method for detecting hexamethylenediamine

Abstract

The present invention relates to the technical field of the detection of hexamethylenediamine, and in particular relates to a method for detecting hexamethylenediamine. A quantitative detection method for hexamethylenediamine comprises the following steps: adding tetraaldehyde tetraphenylethylene into a solution to be detected, adjusting the pH of the solution to alkaline, reacting same, then performing ultraviolet radiation to determine the fluorescence intensity y, and obtaining the concentration of hexamethylenediamine according to a standard curve. In the present invention, tetraaldehyde tetraphenylethylene is used to detect 1,6-hexamethylenediamine, and a relatively high fluorescence intensity can be detected. The concentration of 1,6-hexamethylenediamine in the range of 0.2-20 mg / L is in a good linear relationship with the fluorescence intensity of a product obtained after same reacts with tetraaldehyde tetraphenylethylene, and the detection limit is 0.109 mg / L. The method has the advantages of simplicity, convenience and a low detection limit, and is expected to be further applied with respect to determining the content of hexamethylenediamine.

Description

A method for detecting hexamethylenediamine Technical Field

[0001] The present invention relates to the technical field of hexamethylenediamine detection, in particular to a method for detecting hexamethylenediamine. Background Art

[0002] 1,6-Hexanediamine is widely used in chemical industry products and is a crucial raw material. At room temperature, it is a colorless solid with a strong ammonia odor. It is a highly alkaline organic compound and a toxic substance with physiological effects on the human body. Hexanediamine has a melting point of 42-45°C and a boiling point of 204-205°C. It is readily soluble in common solvents such as ethanol, water, benzene, and ether. As an extremely important intermediate in chemical production, hexanediamine has a wide range of applications, primarily in plastic stabilizers, nylon 66 salt, polyamide resin inks, aluminum-plastic panel adhesives, textile printing and dyeing fixatives, epoxy resin coating curing agents, oilfield demulsifiers, dry-hanging adhesive additives, water treatment additives, and organic crosslinking agents. With China's rapid economic growth, the increase in food manufacturing companies, and the globalization of food trade, the chemical safety of food has become a growing concern. Food contact plastics are essential materials in food production, transportation, and storage, while hexamethylenediamine is a key additive in the production of food contact paints and coatings. Due to the characteristics of food and the physical properties of the materials, chemicals used in the production of food contact materials may migrate into food during use and storage, potentially exposing the human body to hexamethylenediamine. Excessive intake of hexamethylenediamine can affect health. Therefore, detecting hexamethylenediamine levels is of great significance to human life and industrial production.

[0003] Currently, there are many methods for detecting aliphatic amines, primarily spectrophotometry, high-performance liquid chromatography (HPLC), gas chromatography (GC), ultraviolet-visible detection, electrochemical detection, and capillary electrophoresis. The current national standard method for detecting hexamethylenediamine in food contact materials (GB / T 23296.17-2009) recommends separation using a gas chromatography column and detection using a hydrogen flame ionization detector. However, this method is relatively difficult to detect due to complex operation and long analysis times. Compared to these methods, fluorescence detection is a simple, rapid, and inexpensive method. Therefore, in recent years, researchers have attempted to combine fluorescence derivatization with HPLC for the detection of aliphatic amines. Studies have shown that this method is superior to HPLC alone. In search of a more convenient method, fluorescent sensing materials based on various detection principles have been designed for the fluorescent detection of aliphatic amines. Wu Xiaofu et al. synthesized hyperbranched conjugated polymer nanoparticles containing phosphate side chains, achieving selective fluorescent detection of hexamethylenediamine.

[0004] However, traditional organic light-emitting molecules often exhibit excellent luminescence properties in solution or in a monodispersed state. However, once the molecules aggregate into a solid state, the luminescence intensity decreases dramatically or even disappears. This phenomenon, known as aggregation-caused quenching (ACQ), severely restricts the application of organic light-emitting materials.

[0005] Summary of the Invention

[0006] Based on the above content, the present invention provides a method for detecting hexamethylenediamine, which has the characteristics of simple operation and convenient detection, and can realize the detection of hexamethylenediamine content.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] One of the technical solutions of the present invention is a qualitative detection method for hexamethylenediamine (DAH), comprising the following steps: adding a Britton-Robison buffer solution and a tetraaldehyde tetraphenylethylene solution to a test solution to obtain a mixed solution, reacting the solution, and then subjecting the solution to ultraviolet irradiation; if fluorescence is present, it is determined that the test solution contains hexamethylenediamine; if no fluorescence is present, it is determined that the solution does not contain hexamethylenediamine.

[0009] Furthermore, the concentration of the tetraaldehyde tetraphenylethylene in the mixed solution is 30-50 mg / L.

[0010] The pH of the mixed solution is 8.3-9.5.

[0011] Furthermore, the reaction temperature is 85-95° C. and the reaction time is 210-240 min.

[0012] Furthermore, the volume ratio of the Britton-Robison buffer solution to the test solution is 5:4; the concentration of the Britton-Robison buffer solution is 0.04 mol / L; the tetraaldehyde tetraphenylethylene solution is specifically an ethanol solution of tetraaldehyde tetraphenylethylene; the concentration of tetraaldehyde tetraphenylethylene in the tetraaldehyde tetraphenylethylene solution is 400 mg / L.

[0013] The preparation method of the Britton-Robison buffer solution comprises the following steps:

[0014] Phosphoric acid, boric acid, and glacial acetic acid were weighed and dissolved in ultrapure water to obtain a buffer solution, which was then adjusted for acidity and base using a 0.2 mol / L sodium hydroxide solution to obtain a Britton-Robison buffer solution.

[0015] The concentration of phosphoric acid in the buffer solution is 0.392 g / 100 mL, the concentration of boric acid is 0.247 g / 100 mL, and the concentration of acetic acid is 0.240 g / 100 mL.

[0016] Furthermore, the wavelength of the ultraviolet irradiation is 365 nm.

[0017] A second technical solution of the present invention is a method for quantitatively detecting hexamethylenediamine, comprising the following steps: adding a Britton-Robison buffer solution and a tetraaldehyde tetraphenylethylene solution to a test solution to obtain a mixed solution, reacting the solution, then measuring the fluorescence intensity y under ultraviolet irradiation, plotting a concentration curve using a standard, obtaining a linear equation through data processing, and substituting the fluorescence intensity y into the linear equation to obtain the concentration of hexamethylenediamine.

[0018] Furthermore, the concentration of the tetraaldehyde tetraphenylethylene in the reaction solution is 30-50 mg / L.

[0019] The pH of the mixed solution is 8.3-9.5.

[0020] Furthermore, the reaction temperature is 85-95° C. and the reaction time is 210-240 min.

[0021] Furthermore, the volume ratio of the Britton-Robison buffer solution to the test solution is 5:4; the concentration of the Britton-Robison buffer solution is 0.04 mol / L; the tetraaldehyde tetraphenylethylene solution is specifically an ethanol solution of tetraaldehyde tetraphenylethylene; the concentration of tetraaldehyde tetraphenylethylene in the tetraaldehyde tetraphenylethylene solution is 400 mg / L.

[0022] Furthermore, the wavelength of the ultraviolet irradiation is 365-398 nm.

[0023] Furthermore, the concentration of hexamethylenediamine in the mixed solution is 0.1-20 mg / L.

[0024] The present invention discloses the following technical effects:

[0025] This study uses tetraaldehyde tetraphenylethylene to detect 1,6-hexanediamine, demonstrating strong fluorescence intensity and demonstrating the feasibility of using tetraaldehyde tetraphenylethylene for the detection of 1,6-hexanediamine. The fluorescence intensity of the product of the reaction with tetraaldehyde tetraphenylethylene exhibits a good linear relationship within the 1,6-hexanediamine concentration range of 0.2 to 20 mg / L, with a detection limit of 0.109 mg / L and a calculated limit of quantification of 0.364 mg / L, which is lower than the limit of quantification specified in the national standard method (0.5 mg / L). This method offers the advantages of simplicity, convenience, and a low detection limit, and is expected to be further applied to the detection of hexanediamine content. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] FIG1 shows the observation conditions of samples 1, 2, and 3 in the UV dark box of the present invention.

[0028] FIG2 is a reaction product of tetraaldehyde tetraphenylethylene and 1,6-hexanediamine according to the present invention.

[0029] FIG3 is a graph showing the concentration optimization data of tetraaldehyde tetraphenylethylene according to the present invention.

[0030] FIG4 is a temperature and time optimization diagram of the present invention.

[0031] FIG5 is a pH optimization diagram of the present invention; wherein a is a dark box observation diagram of pH 5-10, and b is a pH optimization data diagram.

[0032] FIG6 is a working curve data diagram of 1,6-hexanediamine of the present invention.

[0033] FIG7 is a diagram of the selectivity experiment of the present invention. DETAILED DESCRIPTION

[0034] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0035] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0036] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0037] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0038] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0039] Example 1

[0040] Step 1. Solution preparation

[0041] 400 mg / L Tetrakis(4-formylphenyl)ethene (TFPE) stock solution: Weigh 0.0040 g TFPE into a 10 mL centrifuge tube, dissolve it in anhydrous ethanol, use ultrasonic wave to assist dissolution, and make up to volume in a 10 mL volumetric flask. Shake well and store at room temperature.

[0042] 2000 mg / L 1,6-Diamine (DAH) stock solution: Weigh 0.020 g of DAH into a 10 mL beaker, dissolve it with anhydrous ethanol and dilute to volume in a 10 mL volumetric flask, shake well, and store at room temperature.

[0043] 0.04 mol / L Britton-Robison buffer solution (BR buffer solution): Weigh 0.392 g phosphoric acid, 0.247 g boric acid, and 0.240 g glacial acetic acid into a 50 mL beaker. Dissolve the solution with a certain volume of ultrapure water and adjust the volume to 100 mL volumetric flask. Adjust the pH of the prepared buffer solution using 0.2 mol / L sodium hydroxide solution using a pH meter. Prepare several BR buffer solutions with different pH values ​​and store at room temperature.

[0044] Step 2: Test solution testing conditions and data selection method

[0045] After the TFPE stock solution and the DAH stock solution were mixed and reacted, they were placed in a 1 mL cuvette. The fluorescence intensity I of the system was measured using a fluorescence spectrometer (Fluoromax-4) with an excitation wavelength of 398 nm, an emission wavelength of 420 nm to 650 nm, and an excitation and emission slit width of 2 nm. Each set of test solutions was tested in parallel three times to reduce experimental errors, and the average of the three measurements was taken as the final result.

[0046] Step 3: Feasibility analysis of DAH detection

[0047] Feasibility analysis of DAH detection: By controlling variables and setting up three control experiments, the feasibility of the experiment was verified by comparing the luminescence of three different test solutions, namely, sample 1 (TFPE + DAH), sample 2 (pure TFPE), and sample 3 (pure DAH), observed in a dark box. The specific experimental plan is shown in Table 1 below:

[0048] Table 1 Specific scheme of control experiment

[0049] Note: The concentration of TFPE solution is 400 mg / L; the concentration of DAH solution is 200 mg / L.

[0050] Step 4: Optimization of reaction conditions

[0051] a) TFPE concentration optimization

[0052] Use a pipette to pipette specific volumes of TFPE solutions of varying concentrations and DAH solutions of the same concentration to allow for full reaction (TFPE concentrations in the reaction solution were 10, 20, 30, 40, 50, and 60 mg / L, respectively; DAH concentration was 20 mg / L). After the reaction, measure fluorescence intensity under the assay conditions and select the optimal TFPE concentration based on the intensity.

[0053] b) Temperature and time optimization

[0054] Take several 1.5mL centrifuge tubes and add 160μL pH = 9.5 BR buffer solution, 20μL 400 mg / LTFPE solution, and 20μL 200mg / LDAH solution (a total of 200μL solution) in sequence. After mixing them evenly, react at 63℃, 65℃, 75℃, 85℃, and 95℃ respectively. Take out one tube of reaction solution every 30 minutes and add 800μL anhydrous ethanol to 1mL. After shaking, measure its fluorescence intensity under the detection conditions. Select the optimal temperature and time according to different fluorescence intensity measurement results.

[0055] c) pH optimization

[0056] The Britton-Robison buffer solution has a buffer range of 1.8 to 11.9. BR buffer solutions with pH values ​​of 5, 6, 7, 8, 9, and 10 were prepared according to the BR buffer solution preparation method in step 1. BR buffer solutions with different pH values ​​at intervals of 0.3 were also prepared within the 8.0 to 10.0 buffer range. To a 1.5 mL centrifuge tube, 160 μL of BR buffer solution of varying pH values, 20 μL of 400 mg / L TFPE solution, and 20 μL of 200 mg / L DAH solution were added. Mix thoroughly and react at 85°C for 240 min. After completion, add 800 μL of anhydrous ethanol to 1 mL of the solution. After shaking, measure the fluorescence intensity under the detection conditions. The optimal pH value was determined based on the fluorescence intensity.

[0057] Step 5: Check the DAH working curve

[0058] To a 1.5 mL centrifuge tube, add 160 μL of pH 9.5 BR buffer solution, 20 μL of 400 mg / L TFPE solution, and 20 μL of DAH solutions of varying concentrations. Mix thoroughly and incubate at 85°C for 240 minutes. After completion, add 800 μL of anhydrous ethanol to a final volume of 1 mL. The fluorescence intensity (I) of the system was measured using a fluorescence spectrometer (Fluoromax-4) under the assay conditions. The fluorescence intensity (I0) of the blank control (i.e., without DAH solution) was measured using the same method under the same conditions. The relative fluorescence intensity (ΔI) was calculated as I - I0, and a working curve was plotted using ΔI.

[0059] Step 6: Optional Experiments

[0060] We selected all possible ingredients in plastic-packaged beverages for testing to eliminate interference from other ingredients in the beverages with the hexamethylenediamine detection. These ingredients included ethylenediamine, amino acids, vitamins, sodium chloride, magnesium, iron, copper, potassium, zinc, calcium, and other cationic compounds. These ingredients were tested both individually and in combination. 100 μL, pH = 9.5 BR buffer solution was mixed with 20 μL, 0.4 g / L TFPE and 80 μL of a mixed solution of all beverage ingredients, 0.05 g / L of each ingredient (including 0.005 g / L of ethylenediamine and hexamethylenediamine) as a mixed experimental group; 100 μL, pH = 9.5 BR buffer solution was mixed with 20 μL, 0.4 g / L TFPE and 80 μL of ultrapure water as a blank group; 100 μL, pH = 9.5 BR buffer solution was mixed with 20 μL, 0.4 g / L TFPE and 80 μL, 0.05 g / L beverage ingredients (so that the concentrations of the ingredients were 0.05 g / L, including 0.005 g / L of ethylenediamine and hexamethylenediamine) as a separate experimental group, and placed in an oven at a constant temperature of 85°C for 4 hours for heating reaction. After the reaction, 800 μL of anhydrous ethanol was added for dilution, and the mixtures were placed in 1.5 mL centrifuge tubes, shaken, and placed in 1 mL cuvettes to measure the fluorescence intensity under the detection conditions.

[0061] Step 7: Standard addition of food simulants

[0062] Accurately pipette 10 mL of the beverage into a beaker. Adjust the pH to 9 using a PHS-3EPH meter with sodium hydroxide solution. Dose to a 25 mL volumetric flask with ultrapure water and shake well. Add 5 μL of standard hexamethylenediamine solutions of varying concentrations to 2 mL of Sprite (or sports drink) at pH 9 to create spiked Sprite (or sports drink). Mix 500 μL of 0.08 g / L tetrakis(4-formylphenyl)ethylene and 500 μL of the spiked Sprite (or sports drink) for a reaction, using an unspiked sample as a control. After the reaction is complete, place the sample in a 1 mL cuvette and measure the fluorescence intensity under the assay conditions. The hexamethylenediamine concentration in the spiked recovery is calculated using the standard curve.

[0063] Step 8: Migration of Hexamethylenediamine in Food Contact Materials

[0064] Extraction of Food Contact Materials: Set a series of different extraction times and temperatures. Add the simulant to a beaker and heat it to the corresponding test temperature in a digital constant-temperature water bath. Add the simulant, which has reached the test temperature, to the corresponding food contact material. Record the volume of the added food model and place it in the constant-temperature device. Conduct the migration test according to the predetermined test conditions. For bagged samples, place them in a beaker of appropriate size, add the food simulant to the water bath at the test temperature, and perform the migration time preconditioning according to the test conditions specified for the sample.

[0065] To test whether HDA migration occurs and when it occurs, different extraction times and temperatures were set: 1 hour, 2 hours, and 4 hours at 40°C, and 0.5 hour, 1 hour, and 2 hours at 80°C. Testing was then repeated under the same conditions of 85°C for 4 hours. After extraction under different experimental conditions, 144 μL of the extracted food simulant, 36 μL of pH 9.5 BR buffer, and 20 μL of 0.4 g / L TFPE were pipetted and mixed in an oven at 85°C for 4 hours. Following the reaction, 800 μL of anhydrous ethanol was added for dilution. A control group containing the unextracted food simulant was added. Each tube was placed in a 1.5 mL centrifuge tube, shaken, and then placed in a 1 mL cuvette. Fluorescence intensity was measured under the same conditions to detect migration of HDA from the food contact material into the food simulant. The experimental results were applied to the HDA standard curve to determine HDA concentration.

[0066] Here are the results:

[0067] 1. Feasibility analysis of DAH content detection

[0068] The present invention verified the feasibility of the experiment by controlling variables and setting up three different control groups: sample 1 (TFPE + DAH), sample 2 (pure TFPE), and sample 3 (pure DAH). The results were observed in a UV dark box. According to the experimental results (as shown in Figure 1, where sample 1, sample 2, and sample 3 are shown from left to right), sample 1, which contains both TFPE and DAH, exhibited clear green fluorescence under a 365nm UV dark box, while sample 2, which contained only TFPE, or sample 3, which contained only DAH, did not react to produce fluorescence, thus proving the feasibility of the experiment.

[0069] 2. Analysis of reaction products between TFPE and DAH

[0070] The aldehyde groups in TFPE react with the amino groups in DAH and form an infinitely cross-linked polymer (Figure 2). After the reaction forms the polymer, the intramolecular rotation of the benzene rings in the TFPE unit is severely restricted. The rotation of one benzene ring will also cause the entire product to rotate, resulting in the long-term preservation of electronic excitation energy. The intermolecular energy or charge transfer is slow, resulting in a significant enhancement of the fluorescence of the system.

[0071] 3. Optimization of assay conditions

[0072] 3.1 TFPE concentration optimization

[0073] To achieve optimal results, the present invention optimized the TFPE concentration and determined the optimal TFPE concentration by measuring fluorescence intensity. Based on the experimental data, a graph was plotted with TFPE concentration as the horizontal axis and relative fluorescence intensity as the vertical axis. The results are shown in Figure 3. As shown in Figure 3, the fluorescence intensity increases with increasing TFPE concentration, gradually stabilizing after reaching a certain level. When the TFPE concentration exceeds 40 mg / L, the fluorescence intensity decreases. This is because crosslinking only occurs when the molar ratio of TFPE to DAH remains within a certain range. If the TFPE concentration exceeds this range, the fluorescence intensity decreases. Therefore, a TFPE concentration of 40 mg / L is the optimal concentration for the reaction between TFPE and DAH.

[0074] 3.2 Temperature and time optimization

[0075] To achieve optimal experimental results, the present invention optimized the reaction temperature and time. After reacting at different temperatures for a certain period of time, the fluorescence intensity was measured every 30 minutes. The results were plotted with time as the abscissa and relative fluorescence intensity as the ordinate. The points with an upward trend at each temperature were fitted, resulting in the following results (Figure 4). As shown in Figure 4, the slopes of the fitted lines at 85°C and 95°C are much higher than those at 63°C, 65°C, and 75°C, while the slope of the fitted line at 85°C is similar to that at 95°C. Using a lower temperature can reduce energy use and achieve environmental protection, so a reaction temperature of 85°C is the optimal temperature for the reaction of TFPE and DAH. Under the reaction conditions of 85°C, the fluorescence intensity stabilizes from the 210th minute and shows a downward trend after 240 minutes. Therefore, a reaction time of 240 minutes is the optimal time for the reaction of TFPE and DAH. Therefore, based on the experimental results, a reaction temperature of 85°C for 240 minutes is the optimal temperature and time for the experiment.

[0076] 3.3 pH optimization

[0077] To achieve optimal results, the present invention optimized the pH and prepared solutions with pH values ​​of 5 to 10. After the reaction, samples with pH values ​​of 8, 9, and 10 exhibited significant green fluorescence in a 365nm UV darkroom, while samples with pH values ​​of 5, 6, and 7 showed no fluorescence (Figure 5a), demonstrating that the optimal pH can be found within the pH range of 8 to 10. Britton-Robison buffer solutions with varying pH values ​​at intervals of 0.3 were prepared within the pH range of 8.0 to 10.0. By controlling the variables, BR buffer solutions of varying pH values ​​were added at the same concentration and volume. After reacting at 85°C for 240 minutes, a graph was plotted with the pH values ​​as the horizontal axis and the relative fluorescence intensity as the vertical axis. The following results were obtained (Figure 5b). Figure 5b shows that the fluorescence intensity of the system increases between pH values ​​of 8.3 and 9.2 and stabilizes between pH values ​​of 9.2 and 10.0. Therefore, the optimal pH value for this system is between 9.2 and 10.0, and pH 9.5 was selected for further research.

[0078] 3.4 DAH working curve

[0079] Under the optimal experimental conditions, the fluorescence intensity of DAH at different concentrations was measured, and a DAH working curve was plotted with DAH concentration as the abscissa and the fluorescence intensity change value (I-I0) as the ordinate. The results are shown in Figure 6. As can be seen from Figure 6, the fluorescence intensity shows an upward trend when the DAH concentration ranges from 0.2 to 20 mg / L, so a linear fit was performed within the concentration range of 0.2 to 20 mg / L.

[0080] After data processing, the linear equation is: y = 41428.09845x, R 2 =0.99831. Three blank runs were performed, and the detection limit was calculated using 3σ / k (σ is the standard deviation of the three blank runs, which is 1507.28896, and k is the slope of the linear equation) to be 0.109 mg / L. The quantification limit was calculated using 10σ / k to be 0.364 mg / L, which is lower than the 0.5 mg / L limit specified in the national standard method.

[0081] 3.5 Selective Experiment

[0082] To eliminate interference from other beverage ingredients in the detection of hexamethylenediamine, the present invention conducted selective experiments, including both individual and mixed detection. A graph was plotted with each ingredient as the abscissa and I-I0 as the ordinate. The following results ( FIG7 ) were obtained. As shown in FIG7 , the fluorescence intensities of the mixed sample and hexamethylenediamine are similar, while the fluorescence intensities of the other samples are relatively weak. Therefore, there are almost no ingredients in the beverage that could interfere with the detection of hexamethylenediamine.

[0083] 3.6 Recovery of spiked hexamethylenediamine in food simulants

[0084] In order to calculate the recovery rate of hexamethylenediamine and verify the accuracy of the method of the present invention, the present invention carried out spiked recovery of hexamethylenediamine in food simulants, and obtained the following spiked recovery rates of two food simulants (Table 2).

[0085] Table 2 Recovery of spiked food simulants

[0086] 3.7 Migration of Hexamethylenediamine in Food Contact Materials

[0087] To verify whether hexamethylenediamine migration occurs in food contact materials, as well as the temperature and time at which it occurs, a series of different reaction conditions were set up to extract the food contact materials. Fluorescence intensity was measured under the test conditions. Based on the hexamethylenediamine standard curve, a series of calculations were performed to obtain the results in Tables 3 and 4. Table 3 shows the amount of hexamethylenediamine migration from food contact materials when treated with beverage simulants, and Table 4 shows the amount of hexamethylenediamine migration from food contact materials when treated with water simulants. Tables 3 and 4 show that hexamethylenediamine migration occurs in food contact materials at 40°C for 1 hour and at 80°C for 0.5 hours. Tables 3 and 4 demonstrate that the results obtained when treating food contact materials with different base types of simulants are similar, indicating that this method is not affected by the food simulants.

[0088] Table 3 Migration of hexamethylenediamine in beverage simulant contact materials

[0089] Table 4 Migration of hexamethylenediamine in water contact materials

[0090] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A qualitative detection method for hexamethylenediamine, characterized in that: The following steps are involved: Adding a Britton-Robison buffer solution and a tetraaldehyde tetraphenylethylene solution to a test solution to obtain a mixed solution, reacting, and then irradiating with ultraviolet light; if fluorescence appears, it is determined that the test solution contains hexamethylenediamine; If no fluorescence appears, it is determined that the solution does not contain hexamethylenediamine.

2. The method according to claim 1, characterized in that The concentration of the tetraaldehyde tetraphenylethylene in the mixed solution is 30-50 mg / L.

3. The method according to claim 1, characterized in that The reaction temperature is 85-95°C, the reaction time is 210-240 min, and the pH is 9.2-10.

0.

4. The method according to claim 1, characterized in that: The volume ratio of the Britton-Robison buffer solution to the test solution is 5:4; the concentration of the Britton-Robison buffer solution is 0.04 mol / L; the tetraaldehyde tetraphenylethylene solution is specifically an ethanol solution of tetraaldehyde tetraphenylethylene; the concentration of tetraaldehyde tetraphenylethylene in the tetraaldehyde tetraphenylethylene solution is 400 mg / L.

5. The method according to claim 1, characterized in that The wavelength of the ultraviolet irradiation is 365nm.

6. A quantitative detection method for hexamethylenediamine, characterized in that: The following steps are involved: Add Britton-Robison buffer solution and tetraaldehyde tetraphenylethylene solution to the test solution to obtain a mixed solution, react, and then perform ultraviolet irradiation to determine the fluorescence intensity y. Use a standard to draw a concentration curve. After data processing, a linear equation is obtained. Substitute the fluorescence intensity y into the linear equation to obtain the concentration of hexamethylenediamine.

7. The method according to claim 6, characterized in that The concentration of the tetraaldehyde tetraphenylethylene in the mixed solution is 30-50 mg / L.

8. The method according to claim 6, characterized in that The reaction temperature is 85-95°C, the reaction time is 210-240 min, and the pH is 9.2-10.

0.

9. The method according to claim 6, characterized in that The volume ratio of the Britton-Robison buffer solution to the test solution is 5:4; the concentration of the Britton-Robison buffer solution is 0.04 mol / L; the tetraaldehyde tetraphenylethylene solution is specifically an ethanol solution of tetraaldehyde tetraphenylethylene; the concentration of tetraaldehyde tetraphenylethylene in the tetraaldehyde tetraphenylethylene solution is 400 mg / L.

10. The method according to claim 6, characterized in that The wavelength of the ultraviolet irradiation is 365-398nm.

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