Method for determining chelation effect and chelation rate of compound amino acid trace element chelate
By combining infrared spectroscopy, elemental analysis and water titration, the problem of chelation and chelation rate detection in composite amino acid trace element chelates was solved, high-accuracy detection was achieved, and the development of the composite amino acid trace element industry was promoted.
Patent Information
- Application Number
- CN202510019596.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-07
- Publication Date
- 2025-04-29
AI Technical Summary
The prior art is difficult to accurately detect the chelation effect and chelation rate in the chelating substances of composite amino acid trace elements, resulting in uneven quality of composite amino acid trace elements and hindering industrial development.
The chelation effect and chelation rate of composite amino acid trace element chelates were determined by combining infrared spectroscopy, elemental analysis and water titration. Infrared spectroscopy analyzes the characteristic absorption peak changes of the target to determine the type and intensity of chelation between metal and amino acids; elemental analysis method measures nitrogen content and calculates the total amount of amino acids; anhydrous titration method uses perchloric acid standard solution to calculate the chelation rate.
Accurate detection of composite amino acid trace element chelates is achieved, the determination accuracy is improved, and it can be effectively applied to quality control and detection, ensuring the quality consistency of composite amino acid trace element products.
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Figure CN119901700A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the technical field of analysis and detection, and in particular relates to a method for determining the chelation effect and chelation rate of a composite amino acid trace element chelate. Background Art
[0002] Metal trace elements play an important role in organisms and are important components of certain active intermediates involved in life metabolism. In animal husbandry and breeding, people used to add inorganic salts to meet the needs of animals for trace elements. However, due to the poor physicochemical properties of inorganic salts and the poor absorption effect, excessive addition will cause heavy metal pollution and other problems. People have been exploring new metal trace element additives. Amino acid trace element chelates have good physicochemical properties and good biological activity, which are helpful for animals to absorb trace elements. They are used as trace element supplements for pigs, cattle, sheep, poultry and fish, but the use of a single amino acid has high requirements for ligands, and the raw materials are in short supply and expensive. In order to solve the high cost of amino acid transition metal chelates, in recent years, people have found that amino acids produced by protein hydrolysis as chelating agents have the advantages of low price and moderate stability constant, and based on this, complex amino acid metal chelates have been developed. It has the characteristics of good chemical stability, easy digestion and absorption, low irritation and non-toxicity of a single amino acid metal chelate. While meeting the organism's needs for trace elements, it also supplements a variety of amino acids. Therefore, it is currently considered to be an additive worthy of further widespread application in animal husbandry and breeding industries.
[0003] At present, the identification of chelation and the detection of chelation rate of single amino acid metal chelates are relatively mature. The structure of a single amino acid metal chelate can be determined by single crystal X-ray diffraction, and the chelation form can be directly pointed out. The chelation rate of the amino acid metal chelate can be determined by electrochemical titration analysis, gel filtration chromatography and organic solvent extraction. However, for composite amino acid metal chelates, the above methods are difficult to use directly. This is because on the one hand, the composite amino acid is a mixture and its structure cannot be determined by single crystal X-ray diffraction characterization. On the other hand, the properties of various amino acids are different, and the forms of interaction with metals are diverse. The accuracy of these methods is poor, and the results obtained by different detection methods are quite different, which makes the quality of composite amino acid trace elements on the market uneven, hindering the development of the composite amino acid trace element industry. Therefore, it is urgent to develop a method that can detect the chelation and chelation rate in composite amino acid trace element chelates. Summary of the invention
[0004] The purpose of the present application is to provide a method for determining the chelation effect and chelation rate of a composite amino acid trace element chelate, which has high accuracy and can be well applied to quality control and detection of composite amino acid trace elements.
[0005] This application is implemented through the following technical solutions:
[0006] A method for determining the chelation effect and chelation rate of a composite amino acid trace element chelate, wherein the chelation effect and chelation rate of the composite amino acid trace element chelate are determined by combining infrared spectroscopy, elemental analysis and anhydrous titration, wherein the chelation effect includes the form of action and the intensity of action. In the infrared spectroscopy, the type and intensity of the chelation effect between the metal and the amino acid are determined by the change of the characteristic absorption peak of the target, and the target includes an amine group, a carboxylic acid group and an amide group.
[0007] Preferably, the determination method comprises the following steps:
[0008] (1) Weighing a composite amino acid trace metal chelate sample, grinding and drying it to obtain a powder to be tested;
[0009] (2) grinding a portion of the powder to be tested in step (1) with potassium bromide crystals and then pressing, measuring its infrared spectrum, and determining the type and intensity of the chelation between the metal and the amino acid by analyzing the change in the characteristic absorption peak of the target;
[0010] (3) taking another portion of the powder to be tested in step (1), measuring its nitrogen content by elemental analysis, and then calculating the total amount of amino acids in the sample;
[0011] (4) taking another portion of the powder to be tested in step (1), heating and refluxing the powder to remove the inorganic salt therein, collecting the solid phase, and drying the solid phase to obtain a solid powder;
[0012] (5) The obtained solid powder is dissolved in glacial acetic acid, stirred and mixed, and crystal violet is added as an indicator. The solution is titrated with a standard perchloric acid solution until the color of the solution changes from purple to green. The end point is when the color does not change for at least 15 seconds. A blank experiment is performed to exclude the influence of reducing substances in the solution, and the chelation rate is obtained by calculation.
[0013] Preferably, the calculation formula of the chelation rate is as follows:
[0014]
[0015] Wherein, a is the nitrogen content of the sample,
[0016] m is the mass of the composite amino acid trace metal chelate sample, g,
[0017] V 1is the consumption of the perchloric acid standard solution, mL,
[0018] V 2 is the consumption of the perchloric acid standard solution in the blank experiment, mL,
[0019] C is the concentration of the perchloric acid standard solution, mol / L,
[0020] 129 is the average molecular weight of amino acids, and the average nitrogen content of conventional amino acids is 16%.
[0021] Preferably, the complex amino acid trace metal chelate comprises one or more of a complex amino acid manganese chelate, a complex amino acid iron chelate, a complex amino acid zinc chelate or a complex amino acid copper chelate.
[0022] Preferably, the drying temperature in step (1) is 80°C.
[0023] Preferably, in step (2), the mass ratio of the powder to be tested to the potassium bromide crystals is (0.05-0.1):(1-2), and they are ground together and pressed into a transparent solid.
[0024] Preferably, the target in step (2) includes an amine group, a carboxylic acid group and an amide group. The characteristic absorption peaks of infrared spectra and their changes are shown in Table 1. In the composite amino acid trace metal chelate, the amine group, the carboxylic acid group and the amide group in the composite amino acid mainly interact with the metal center, so the interaction between these three groups and the metal is concerned.
[0025] Table 1
[0026]
[0027] Preferably, the extraction agent selected in step (4) is methanol, the heating temperature is 80-90° C., and the extraction time is 12-24 hours.
[0028] Preferably, the glacial acetic acid solution of the crystal violet added in step (5) has a concentration of 0.1-0.5%, where the concentration is the percentage of the mass of the crystal violet to the mass of the glacial acetic acid solution, the concentration of the perchloric acid standard solution is 0.01-0.05 mol / L, and the titration process is carried out in a dry environment.
[0029] Preferably, step (4) and step (5) can be repeated, and the final chelation rate is the average value of each time.
[0030] The beneficial effects of this application are:
[0031] 1. The present application uses the characteristic infrared spectrum absorption peak shift in the sample as an indicator to analyze the action form and action intensity in the composite amino acid metal chelate. The method is simple and easy to operate, and can efficiently analyze the action form and action intensity in the composite amino acid metal chelate sample. It can measure a variety of composite amino acid trace metal chelates, including composite amino acid manganese chelates, composite amino acid iron chelates, composite amino acid zinc chelates or composite amino acid copper chelates, etc.
[0032] 2. The present application utilizes the redox reaction principle of amino acids and perchloric acid to titrate free amino acids in the sample, and calculates the chelation rate of amino acid metal chelates in the sample by the total amount of amino acids and the amount of free amino acids. This method is accurate and reliable. In the sample pretreatment, inorganic salts in the sample are removed to prevent the amino acids in the sample from coordinating with inorganic salts under acidic conditions. The test has a high accuracy.
[0033] 3. The application scope of the present application is wide, including but not limited to various types of mixed amino acids or complex amino acid metal chelates, and the types of metals also include trace metals such as manganese, iron, copper and zinc. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Figure 1 This is the infrared spectrum of the composite amino acid metal zinc chelate and the composite amino acid of Example 1.
[0035] Figure 2 This is the infrared spectrum of the composite amino acid metal manganese chelate and the composite amino acid of Example 2.
[0036] Figure 3 This is the infrared spectrum of the composite amino acid metal iron chelate and the composite amino acid of Example 3.
[0037] Figure 4 This is the infrared spectrum of the composite amino acid metal copper chelate and the composite amino acid of Example 4. DETAILED DESCRIPTION
[0038] The technical solution of the present application will be clearly and completely described below in conjunction with specific implementation methods. However, those skilled in the art will understand that the embodiments described below are part of the embodiments of the present application, rather than all of the embodiments, and are only used to illustrate the present application and should not be regarded as limiting the scope of the present application.
[0039] A method for determining the chelation and chelation rate of a composite amino acid trace element chelate, wherein the chelation form and chelation rate of the composite amino acid trace element chelate are determined by infrared spectroscopy, elemental analysis and anhydrous titration. The infrared spectroscopy method determines the type and intensity of the chelation between the metal and the amino acid by the change of the characteristic absorption peak of the target, and the target includes an amine group, a carboxylic acid group and an amide group. The composite amino acid trace metal chelate includes one or more of a composite amino acid manganese chelate, a composite amino acid iron chelate, a composite amino acid zinc chelate or a composite amino acid copper chelate.
[0040] The determination method comprises the following steps:
[0041] (1) Weigh a composite amino acid trace metal chelate sample, grind it and dry it at 80° C. to obtain a powder to be tested.
[0042] (2) taking part of the powder to be tested and potassium bromide crystals in step (1), wherein the mass ratio of the powder to be tested and the potassium bromide crystals is (0.05-0.1):(1-2), grinding them together and pressing them into a transparent solid, measuring their infrared spectrum, and determining the type and intensity of the chelation between the metal and the amino acid by analyzing the changes in the characteristic absorption peaks of the target.
[0043] (3) Take another portion of the powder to be tested in step (1), and measure its nitrogen content by elemental analysis according to JY / T0580-2020 General Rules for Elemental Analyzer Analysis Methods, and then calculate the total amount of amino acids in the sample. The instrument for measuring the nitrogen content includes but is not limited to Elementar's Vario EL CUBE fully automatic elemental analyzer.
[0044] (4) Another portion of the powder to be tested in step (1) is wrapped with filter paper, placed in a Soxhlet extractor, and methanol is added. The mixture is heated to reflux for extraction at a temperature of 80 to 90° C. for an extraction time of 12 to 24 hours to remove inorganic salts therein to make the determination more accurate. The solid phase is collected and dried to obtain a solid powder.
[0045] (5) In a dry environment, the obtained solid powder is dissolved in glacial acetic acid, stirred and mixed, and crystal violet is added as an indicator, and a glacial acetic acid solution of crystal violet is added at a concentration of 0.1-0.5%. A standard perchloric acid solution with a concentration of 0.01-0.05 mol / L is used to titrate until the color of the solution changes from purple to green. The end point is when the color does not change for at least 15 seconds, and a blank experiment is required to exclude the influence of reducing substances in the solution, and the chelation rate is obtained by calculation.
[0046] The calculation formula of chelation rate is as follows:
[0047]
[0048] Wherein, a is the nitrogen content of the sample,
[0049] m is the mass of the composite amino acid trace metal chelate sample, g,
[0050] V 1 is the consumption of the perchloric acid standard solution, mL,
[0051] V 2 is the consumption of the perchloric acid standard solution in the blank experiment, mL,
[0052] C is the concentration of the perchloric acid standard solution, mol / L,
[0053] 129 is the average molecular weight of amino acids, and the average nitrogen content of conventional amino acids is 16%.
[0054] Example 1
[0055] (1) Weigh 1.5 g of a composite amino acid zinc chelate sample, grind it in a mortar, and dry it in an oven at 80° C. to obtain a powder to be tested.
[0056] (2) Grind 0.1 g of sample with 1.5 g of potassium bromide crystals and press into a transparent solid. Measure its infrared spectrum. Figure 1 The infrared spectrum of the composite amino acid metal zinc chelate is shown. According to the characteristic absorption peaks of the above targets, the changes can be found by analyzing the changes. As the N of the amine group coordinates to the metal center, the stretching vibration of the NH bond (3288cm -1 ) did not change significantly, indicating that there was no interaction between the metal and the amino group. The characteristic absorption peak of the carboxylic acid carbonyl group (1733 cm -1 ) has a significant change in intensity (+8cm -1 ), indicating that the chelation between the carboxylate and the metal center is strong. At the same time, the strength of the interaction between the amide carbonyl and the metal is also strong (1662cm -1 ), the characteristic peak changes greatly (-18cm -1 The NH bending vibration of the amide group undergoes a small blue shift of -2 cm -1 , indicating that the amide carbonyl and amide amine groups have weak coordination with the zinc metal center. In summary, in the composite amino acid metal zinc chelate, the metal center has a strong chelation effect with the carboxyl and amide carbonyl groups of the composite amino acid, but has no obvious effect with the amino group and the amide bond in the amide group.
[0057] (3) Another 20 mg sample was taken after drying, and its N content was measured by using Elementar's Vario EL CUBE fully automatic elemental analyzer according to JY / T0580-2020 General Rules for Elemental Analyzer Analysis Methods, and the content was 3.65%.
[0058] (4) Take another 0.40 g of the ground sample, wrap it with filter paper, put it in a Soxhlet extractor, add 200 mL of methanol, heat and reflux for 12 hours, and extract at a heating temperature of 90°C to remove the inorganic salts. The treated sample is dried to obtain 0.36 g of solid powder.
[0059] (5) Dissolve the solid powder in 200 mL of glacial acetic acid, stir and mix, then add 2 drops of crystal violet (chemical formula: C 25 H 30 C1N 3 , CAS No.: 548-62-9) as an indicator, use 0.010mol / L perchloric acid standard solution to titrate until the solution color changes from purple to green, and maintain it for 15 seconds without changing color, which is the end point. A total of 13.98mL of perchloric acid standard solution is consumed. The operation steps must be quick. The blank experiment operation steps are the same, and the consumption of 0.50mL of perchloric acid standard solution is recorded. The corresponding chelation rate can be calculated by the formula:
[0060]
[0061] Steps (4) and (5) were repeated, and the chelation rate of the sample measured for the second time was 88.0%. The average chelation rate of the composite amino acid zinc chelate obtained from the two measurements was 84.2%.
[0062] Example 2
[0063] (1) Weigh 1.5 g of a composite amino acid manganese chelate sample, grind it in a mortar, and dry it in an oven at 80°C.
[0064] (2) Grind 0.1 g of sample with 1.2 g of potassium bromide crystals and press into a transparent solid. Measure its infrared spectrum. Figure 2 As shown in the figure, it is the infrared spectrum of the composite amino acid metal manganese chelate. According to the characteristic absorption peaks of the above targets, it can be found by analyzing its changes that the stretching vibration of the NH bond changes from 3288cm to 4287cm due to the coordination of the N of the amine group to the metal center. -1 Reduced to 3281cm -1 , changes to -7cm -1 , indicating that there is a moderate interaction between the metal and the amino group. The characteristic absorption peak of the carboxylic acid carbonyl group (1729cm -1 ) has obvious changes +4cm -1 , indicating that the carboxylate group has a certain chelating effect with the metal center. The strength of the interaction between the amide carbonyl group and the metal is also weak (1678cm -1 ), the characteristic peaks only change slightly. The NH bending vibration of the amide group (1538cm -1) also changed slightly, indicating that the amide carbonyl and amide amine groups had basically no coordination effect with the manganese metal center. In summary, in the composite amino acid metal manganese chelate, the metal center had a moderate interaction with the amino group of the composite amino acid, had a certain interaction with the carboxyl part, but had a weak chelation effect with the amide bond.
[0065] (3) Another 20 mg sample was taken after drying, and its N content was measured by using Elementar's Vario EL CUBE fully automatic elemental analyzer according to JY / T0580-2020 General Rules for Elemental Analyzer Analysis Methods, and the content was 3.75%.
[0066] (4) Take 0.40 g of the ground sample, wrap it with filter paper, place it in a Soxhlet extractor, add 200 mL of methanol, heat and reflux for 12 hours, and extract at a heating temperature of 90°C to remove the inorganic salts. The treated sample is dried to obtain 0.38 g of solid powder.
[0067] (5) Dissolve the solid powder in 200 mL of glacial acetic acid, stir and mix, add 2 drops of crystal violet as an indicator, and titrate with 0.010 mol / L perchloric acid standard solution until the solution changes from purple to green. Maintaining the color for 15 seconds without changing color is the end point. A total of 6.52 mL of perchloric acid standard solution is consumed. The blank experiment operation steps are the same, and the consumption of 0.50 mL of perchloric acid standard solution is recorded. The corresponding chelation rate can be calculated by the formula:
[0068]
[0069] Steps (4) and (5) were repeated, and the chelation rate of the sample was measured for the second time, which was 91.2%. The average chelation rate of the composite amino acid manganese chelate was 91.2%.
[0070] Example 3
[0071] (1) Weigh 1.5 g of a composite amino acid iron chelate sample, grind it in a mortar, and dry it in an oven at 80° C. to obtain a powder to be tested.
[0072] (2) Grind 0.1 g of sample with 1.7 g of potassium bromide crystals and press into a transparent solid. Measure its infrared spectrum. Figure 3 The infrared spectrum of the composite amino acid metal iron chelate is shown. According to the characteristic absorption peaks of the above targets, the change of the absorption peaks can be found that the stretching vibration of the NH bond changes from 3288 cm to 4287 cm due to the coordination of the N of the amine group to the metal center. -1 Reduced to 3274cm -1 , changes to -14cm -1 , indicating that there is a strong interaction between metal and amino groups. The characteristic absorption peak of carboxylic acid carbonyl (1728cm -1) changes slightly, but the interaction is not strong, indicating that the chelation between the carboxylate and the metal center is weak. The interaction between the amide carbonyl and the metal is also weak (1678cm -1 ), the characteristic peaks only change slightly. The NH bending vibration of the amide group has a significant blue shift -17cm -1 , indicating that the amide carbonyl and amide amine groups have strong coordination with the iron metal center. In summary, in the composite amino acid metal iron chelate, the metal center has a strong interaction with the amino group of the composite amino acid, and a weak chelation with the carboxyl part. At the same time, there are a certain amount of dipeptides and polypeptides in the composite amino acid, and the amide bond in them also has a strong interaction with the metal center.
[0073] (3) Another 20 mg sample was taken after drying, and its N content was measured by using Elementar's Vario EL CUBE fully automatic elemental analyzer according to JY / T0580-2020 General Rules for Elemental Analyzer Analysis Methods, and the content was 5.02%.
[0074] (4) Take another 0.50 g of the ground sample, wrap it with filter paper, put it in a Soxhlet extractor, add 200 mL of methanol, heat and reflux for 12 hours at 90°C, and extract and remove the inorganic salts. The treated sample is dried to obtain 0.46 g of solid powder.
[0075] (5) Dissolve the solid powder in 250 mL of glacial acetic acid, stir and mix, add 2 drops of crystal violet as an indicator, and titrate with 0.010 mol / L perchloric acid standard solution until the solution changes from purple to green. Maintaining the solution for 15 seconds without discoloration is the end point. A total of 18.77 mL of perchloric acid standard solution is consumed. The operation steps should be fast. The blank experiment operation steps are the same, and the consumption of 0.50 mL of perchloric acid standard solution is recorded. The corresponding chelation rate can be calculated by the formula:
[0076]
[0077] Steps (4) and (5) were repeated, and the chelation rate of the sample measured for the second time was 90.9%. The average chelation rate of the composite amino acid iron chelate obtained from the two times was 87.9%.
[0078] Example 4
[0079] (1) Weigh 1.0 g of a composite amino acid copper chelate sample, grind it in a mortar, and dry it in an oven at 80° C. to obtain a powder to be tested.
[0080] (2) Grind 0.1 g of sample with 1.9 g of potassium bromide crystals and press into a transparent solid. Measure its infrared spectrum. Figure 4The infrared spectrum of the composite amino acid metal copper chelate is shown. According to the characteristic absorption peaks of the above targets, the change of the absorption peaks can be found that the stretching vibration of the NH bond changes from 3288 cm to 4287 cm due to the coordination of the N of the amine group to the metal center. -1 Reduced to 3276cm -1 , changes to -12cm -1 , indicating that there is a strong interaction between metal and amino groups. The characteristic absorption peak of carboxylic acid carbonyl (1732cm -1 ) has a significant change (+7cm -1 ), the chelation between the surface carboxylate and the metal center is strong. The strength of the interaction between the amide carbonyl and the metal is also strong (1668cm -1 ), the characteristic peak changes greatly (-12cm -1 The NH bending vibration of the amide group undergoes a small blue shift of -2 cm -1 , indicating that the coordination between the amide carbonyl group and the amide amine group and the copper metal center is weak. In summary, in the composite amino acid metal copper chelate, the metal center has a strong interaction with the amino group of the composite amino acid, and has a strong chelation effect with the carboxyl group and the carbonyl group of the amide, but the interaction between the amide bond and the metal center is weak.
[0081] (3) Another 20 mg sample was taken after drying, and its N content was measured by using Elementar's Vario EL CUBE fully automatic elemental analyzer according to JY / T0580-2020 General Rules for Elemental Analyzer Analysis Methods, and the content was 3.99%.
[0082] (4) Take another 0.30 g of the ground sample, wrap it with filter paper, put it in a Soxhlet extractor, add 200 mL of methanol, heat and reflux for 12 hours at 90°C, and extract and remove the inorganic salts. The treated sample is dried to obtain 0.28 g of solid powder.
[0083] (5) Dissolve the solid powder in 200 mL of glacial acetic acid, stir and mix, add 2 drops of crystal violet as an indicator, and titrate with 0.010 mol / L perchloric acid standard solution until the solution changes from purple to green. Maintaining the color for 15 seconds without changing color is the end point. A total of 8.63 mL of perchloric acid standard solution is consumed. The operation steps should be fast. The blank experiment operation steps are the same, and the consumption of 0.50 mL of perchloric acid standard solution is recorded. The corresponding chelation rate can be calculated by the formula:
[0084]
[0085] Steps (4) and (5) were repeated, and the chelation rate of the sample was measured for the second time, which was 86.9%. The average chelation rate of the composite amino acid copper chelate was 86.1%.
[0086] The present application has high accuracy, and it has been verified that the chelation rate values measured each time in each embodiment are concentrated, and the data deviation is very small, which effectively overcomes the problems existing in the prior art.
[0087] Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A method for determining the chelation effect and chelation rate of a composite amino acid trace element chelate, characterized in that: The chelation effect and chelation rate of the composite amino acid trace element chelate are determined by infrared spectroscopy, elemental analysis and anhydrous titration. The chelation effect includes the action form and action intensity.
2. The method for determining the chelation effect and chelation rate of the composite amino acid trace element chelate according to claim 1, characterized in that: The following steps are involved: (1) Weighing a composite amino acid trace metal chelate sample, grinding and drying it to obtain a powder to be tested; (2) grinding a portion of the powder to be tested in step (1) with potassium bromide crystals and then pressing, measuring its infrared spectrum, and determining the type and intensity of the chelation between the metal and the amino acid by analyzing the change in the characteristic absorption peak of the target; (3) taking another portion of the powder to be tested in step (1), measuring its nitrogen content by elemental analysis, and then calculating the total amount of amino acids in the sample; (4) taking another portion of the powder to be tested in step (1), heating and refluxing the powder to remove the inorganic salt therein, collecting the solid phase, and drying the solid phase to obtain a solid powder; (5) The obtained solid powder is dissolved in glacial acetic acid, stirred and mixed, and crystal violet is added as an indicator. The solution is titrated with a standard perchloric acid solution until the color of the solution changes from purple to green. The end point is when the color does not change for at least 15 seconds. A blank experiment is performed to exclude the influence of reducing substances in the solution, and the chelation rate is obtained by calculation.
3. The method for determining the chelation effect and chelation rate of the composite amino acid trace element chelate according to claim 2, characterized in that: The calculation formula of the chelation rate is as follows: Wherein, a is the nitrogen content of the sample, m is the mass of the composite amino acid trace metal chelate sample, g, V1 is the consumption of the perchloric acid standard solution, mL, V2 is the consumption of the perchloric acid standard solution in the blank experiment, mL, C is the concentration of the perchloric acid standard solution, mol / L, 129 is the average molecular weight of amino acids, and the average nitrogen content of conventional amino acids is 16%.
4. The method for determining the chelation effect and chelation rate of the composite amino acid trace element chelate according to claim 1, characterized in that: The composite amino acid trace metal chelate comprises one or more of a composite amino acid manganese chelate, a composite amino acid iron chelate, a composite amino acid zinc chelate or a composite amino acid copper chelate.
5. The method for determining the chelation effect and chelation rate of the composite amino acid trace element chelate according to claim 2, characterized in that: The drying temperature in step (1) is 80°C.
6. The method for determining the chelation effect and chelation rate of the composite amino acid trace element chelate according to claim 2, characterized in that: In step (2), the mass ratio of the powder to be tested to the potassium bromide crystals is (0.05-0.1):(1-2), and they are ground together and pressed into a transparent solid.
7. The method for determining the chelation effect and chelation rate of the composite amino acid trace element chelate according to claim 2, characterized in that: The targets in step (2) include amine groups, carboxylic acid groups and amide groups.
8. The method for determining the chelation effect and chelation rate of the composite amino acid trace element chelate according to claim 2, characterized in that: The extraction agent selected in step (4) is methanol, the heating temperature is 80-90° C., and the extraction time is 12-24 hours.
9. The method for determining the chelation effect and chelation rate of the composite amino acid trace element chelate according to claim 2, characterized in that: In step (5), the glacial acetic acid solution of the crystal violet is added at a concentration of 0.1-0.5%, and the concentration of the perchloric acid standard solution is 0.01-0.05 mol / L. The titration process is carried out in a dry environment.
10. The method for determining the chelation effect and chelation rate of the composite amino acid trace element chelate according to claim 2, characterized in that: Step (4) and step (5) can be repeated, and the final chelation rate is the average value of each time.