Method for testing the content of complexing additives

Abstract

This invention relates to the field of liquid chromatography detection technology, specifically to a method for testing the content of compound additives. The method includes the following steps: (1) mixing the compound additive with a derivatizing solution and performing a colorimetric reaction at 50-80°C to obtain a test solution; wherein the compound additive includes amine antistatic agents and antioxidants; (2) detecting the test solution using high-performance liquid chromatography to obtain the content of amine antistatic agents and antioxidants. The method for testing the content of compound additives provided in this invention can simultaneously determine the content of amine antistatic agents in compound additives and the content of common antioxidants in compound additives, achieving multiple effects at the same time, improving testing efficiency, and obtaining accurate and precise results, making it suitable for widespread application.

Description

Technical Field

[0001] This invention relates to the field of liquid chromatography detection technology, specifically to a method for testing the content of compound additives, particularly a method for testing the content of amine antistatic agents and antioxidants. Background Technology

[0002] Polyolefin polymers are widely used in industrial production and daily life due to their ease of processing, lightweight, high strength, and low cost. To impart specific properties to polyolefin materials or improve their performance, compound additives are typically added.

[0003] The components in compound additives generally include antistatic agents and antioxidants. The most commonly used antistatic agents are amine antistatic agents. When testing the content of each component in compound additives, amine antistatic agents cannot be titrated normally for amine value, lack characteristic absorption in the ultraviolet-visible band, have high boiling points and are difficult to vaporize, which makes it impossible to test amine antistatic agents and antioxidants simultaneously. Summary of the Invention

[0004] The purpose of this invention is to solve the problem that it is difficult to test amine antistatic agents and antioxidants simultaneously in the existing technology, and to provide a method for testing the content of compound additives.

[0005] To achieve the above objectives, the present invention provides a method for testing the content of compound additives, the method comprising the following steps:

[0006] (1) The compound additive is mixed with the derivatizing solution and a colorimetric reaction is carried out at 50-80℃ to obtain the test solution; wherein, the compound additive includes amine antistatic agents and antioxidants;

[0007] (2) The test liquid is detected by high performance liquid chromatography to obtain the content of amine antistatic agent and antioxidant.

[0008] The beneficial technical effects achieved by the present invention through the above technical solution are as follows:

[0009] 1) The method for testing the content of compound additives provided in this invention can simultaneously determine the content of amine antistatic agents in compound additives and the content of common antioxidants in compound additives, thus improving testing efficiency by combining multiple functions.

[0010] 2) The method for testing the content of compound additives provided in this invention yields accurate and highly precise results;

[0011] 3) The method for testing the content of compound additives provided in this invention is simple to operate and does not require the use of highly toxic reagents, making it suitable for widespread application. Attached Figure Description

[0012] Figure 1 This is the chromatogram of the test solution of the antistatic agent 1800 standard in Example 1;

[0013] Figure 2 This is the chromatogram of the test solution of antioxidant 1010 standard in Example 1;

[0014] Figure 3 This is the chromatogram of the test solution of antioxidant 168 standard in Example 1;

[0015] Figure 4 This is the chromatogram of the test solution containing the compound additive in Example 1;

[0016] Figure 5 This is the chromatogram of the test solution of antistatic agent 1800 standard in Comparative Example 1;

[0017] Figure 6 This is the chromatogram of the test solution of the antistatic agent 1800 standard in Comparative Example 2. Detailed Implementation

[0018] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0019] This invention provides a method for testing the content of compound additives, the method comprising the following steps:

[0020] (1) The compound additive is mixed with the derivatizing solution and a colorimetric reaction is carried out at 50-80℃ to obtain the test solution; wherein, the compound additive includes amine antistatic agents and antioxidants;

[0021] (2) The test liquid is detected by high performance liquid chromatography to obtain the content of amine antistatic agent and antioxidant.

[0022] In step (1):

[0023] In one embodiment of the present invention, the amine antistatic agent is selected from ethoxylated stearamine antioxidants and / or ethoxylated laurylamine antioxidants.

[0024] In one embodiment of the present invention, preferably, the amine antistatic agent is selected from N,N-dihydroxyethyl octadecylamine and / or octadecylamine polyoxyethylene (2) ether.

[0025] In one embodiment of the present invention, the antioxidant is selected from one or more of antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]), antioxidant 168 (tris(2,4-di-tert-butylphenyl) phosphite), antioxidant 1076 (octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), and antioxidant 626 (pentaerythritol diphosphite of bis(2,4-di-tert-butylphenyl)propionate).

[0026] When the compound additive contains multiple amine antistatic agents and antioxidants, the content of each component can be tested separately using the compound additive content testing method provided in this invention.

[0027] In one embodiment of the present invention, the mass ratio of antistatic agent to antioxidant in the compound additive is 1:0.5-10, preferably 1:2-5.

[0028] In one embodiment of the present invention, the method for preparing the derivatized solution includes: mixing an acid and an anhydride in a solvent at room temperature to obtain the derivatized solution;

[0029] The acid is preferably selected from citric acid and / or 2-hydroxysuccinic acid, and more preferably citric acid; the anhydride is preferably selected from monobasic anhydride and / or dibasic anhydride; more preferably selected from one or more of propionic anhydride, acetic anhydride, citrate anhydride, maleic anhydride, and phthalic anhydride; and more preferably acetic anhydride.

[0030] In one embodiment of the present invention, the solvent is selected from one or more of ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, tetrahydrofuran, and 1,4-dioxane, and is more preferably ethyl acetate and / or acetone.

[0031] In one embodiment of the present invention, the room temperature is not specifically limited and can be 15-35°C.

[0032] In one embodiment of the present invention, the ratio of the amount of acid, acid anhydride and solvent is 1g:1-100mL:30-500mL, preferably 1g:10-30mL:80-180mL.

[0033] In one embodiment of the present invention, the ratio of the compound additive to the derivative solution is 1g:10-150mL, preferably 1g:50-100mL.

[0034] In one embodiment of the present invention, the reaction temperature of the colorimetric reaction is 60-70°C.

[0035] The inventors of this invention discovered through research that when the reaction temperature is above 80°C, byproducts are generated in the colorimetric reaction, making the quantitative results inaccurate; when the reaction temperature is below 50°C, chromatographic peaks above the detection limit of liquid chromatography cannot be observed at the expected peak position of the antistatic agent derivative; and the test results are optimal when the reaction temperature is between 60-70°C.

[0036] In one embodiment of the present invention, the reaction time of the colorimetric reaction is 0.5-4 hours, preferably 1-2 hours.

[0037] In step (2):

[0038] In one embodiment of the present invention, the detector in the high performance liquid chromatograph is an ultraviolet absorption detector with a wavelength of 220-400 nm, preferably 275-325 nm.

[0039] In one embodiment of the present invention, the chromatographic column in the high performance liquid chromatography is selected from a reversed-phase chromatographic column, preferably a reversed-phase C18 chromatographic column.

[0040] In one embodiment of the present invention, the elution method in the high performance liquid chromatography is isocratic elution, and the flow rate of the mobile phase is 0.4-1.8 mL / min, preferably 0.8-1.4 mL / min.

[0041] In one embodiment of the present invention, the mobile phase is selected from methanol, isopropanol, methanol aqueous solution, and isopropanol aqueous solution, preferably methanol or methanol aqueous solution.

[0042] In one embodiment of the present invention, the present invention does not impose a special limitation on the volume content of methanol or isopropanol in the methanol aqueous solution and the isopropanol aqueous solution. Preferably, the volume percentage of methanol in the methanol aqueous solution is 50-90% and the volume percentage of isopropanol in the isopropanol aqueous solution is 50-90%.

[0043] In one embodiment of the present invention, the volume ratio of the test liquid to the mobile phase is 1:0.5-3, preferably 1:1-2.

[0044] In one embodiment of the present invention, the content of antistatic agent and antioxidant is calculated using the external standard method.

[0045] The external standard method refers to determining a standard substance separately under the same chromatographic conditions as the sample being tested, and then comparing the obtained peak area with that of the analyte to determine its content. When calculating component content using the external standard method, a standard curve can be plotted as follows: Prepare a series of amine antistatic agent standard solutions and antioxidant standard solutions of different concentrations. Under the same testing conditions, inject equal volumes accurately, measure the peak area or peak height of each component, and plot a curve using the peak area or peak height of the standard solution against its concentration to obtain the standard curve. Alternatively, prepare a standard solution of amine antistatic agent and an antioxidant standard solution of known concentration, inject equal volumes accurately under the same testing conditions, measure the peak area or peak height of each component, and perform a linear conversion between the peak area or peak height of the standard solution and the sample to calculate the content of each component in the sample.

[0046] In this invention, when the compound additive contains multiple antistatic agents or multiple antioxidants, the various antistatic agents and antioxidants can be mixed together to prepare a standard sample, or each component can be prepared separately as a standard sample.

[0047] The present invention will be described in detail below through examples. The high-performance liquid chromatography (HPLC) used in the examples and comparative examples was a Waters 2695 / 2996 HPLC system, the detector was a UV absorption detector, the chromatographic column was a reversed-phase C18 column, and isocratic elution was used during detection. In the examples and comparative examples, the purity of antistatic agent 1800 was 98%, and the purity of all antioxidants was 99%.

[0048] Example 1

[0049] (1) At room temperature, 2.5000 g of citric acid and 50.0 mL of acetic anhydride were mixed in 450.0 mL of ethyl acetate to obtain a derivatization solution;

[0050] Mix 0.2000g of antistatic agent 1800 with 25.0mL of derivatizing solution and keep in a 70℃ water bath for 1h to obtain a clear and transparent antistatic agent 1800 standard sample test solution.

[0051] Mix 0.2000g of antioxidant 1010 with 25.0mL of derivatizing solution and keep in a 70℃ water bath for 1h to obtain a clear and transparent antioxidant 1010 standard sample test solution.

[0052] Mix 0.2000g of antioxidant 168 with 25.0mL of derivatizing solution and keep in a 70℃ water bath for 1h to obtain a clear and transparent antioxidant 168 standard test solution.

[0053] Mix 0.5000g of compound additive (a mixture of 0.1325g antistatic agent 1800, 0.2585g antioxidant 1010 and 0.1090g antioxidant 168) with 25.0mL of derivatizing solution and keep in a 70℃ water bath for 1h to obtain a clear and transparent compound additive test solution.

[0054] (2) The test solutions of antistatic agent 1800, antioxidant 1010, antioxidant 168, and compound additive were mixed with mobile phase methanol at a ratio of 1:1 and then subjected to liquid chromatography at a detector wavelength of 300 nm and a mobile phase flow rate of 1.2 mL / min. The results of the first test are as follows: Figure 1-4 As shown, the chromatographic peak areas of each component in the test solutions of antistatic agent 1800, antioxidant 1010, antioxidant 168, and compound additive were obtained from the chromatograms. The contents of antistatic agent 1800, antioxidant 1010, and antioxidant 168 in the compound additive were calculated by external standard method.

[0055] The compound additive test solution was tested six times. The relative standard deviation (RSD) of the antistatic agent 1800 content test was 1.5%, the relative standard deviation (RSD) of the antioxidant 1010 content test was 0.9%, and the relative standard deviation (RSD) of the antioxidant 168 content test was 1.2%.

[0056] The average of the results of six tests was taken as the final test result. The actual measured contents of antistatic agent 1800 were 26.2 wt%, antioxidant 1010 were 52.4 wt%, and antioxidant 168 were 22.8 wt%.

[0057] Example 2

[0058] (1) At room temperature, 5g of citric acid and 100.0mL of acetic anhydride were mixed in 400.0mL of ethyl acetate to obtain a derivatization solution;

[0059] Mix 0.2000g of antistatic agent 1800 with 50.0mL of derivatizing solution and keep in a 60℃ water bath for 2h to obtain a clear and transparent antistatic agent 1800 standard sample test solution.

[0060] Mix 0.2000g of antioxidant 1076 with 50.0mL of derivatizing solution and keep in a 60℃ water bath for 2h to obtain a clear and transparent antioxidant 1076 standard test solution.

[0061] Mix 0.2000g of antioxidant 168 with 50.0mL of derivatizing solution and keep in a 60℃ water bath for 2h to obtain a clear and transparent antioxidant 168 standard test solution.

[0062] Mix 0.5000g of compound additive (a mixture of 0.0785g antistatic agent 1800, 0.1020g antioxidant 1076, 0.0990g antioxidant 168, and 0.2205g zinc stearate) with 50.0mL of derivatizing solution and keep in a 60℃ water bath for 2h to obtain a clear and transparent compound additive test solution.

[0063] (2) The test solutions of antistatic agent 1800, antioxidant 1076, antioxidant 168 and compound additive were mixed with the mobile phase methanol aqueous solution (methanol volume fraction of 80%) at a ratio of 1:2 and then subjected to liquid chromatography test under the conditions of detector wavelength of 280 nm and mobile phase flow rate of 1.0 mL / min. The chromatographic peak areas of each component in the test solutions of antistatic agent 1800, antioxidant 1076, antioxidant 168 and compound additive were obtained from the chromatogram. The contents of antistatic agent 1800, antioxidant 1076 and antioxidant 168 in the compound additive were calculated by external standard method.

[0064] The compound additive test solution was tested six times. The relative standard deviation (RSD) of the antistatic agent 1800 content test was 1.8%, the relative standard deviation (RSD) of the antioxidant 1076 content test was 1.7%, and the relative standard deviation (RSD) of the antioxidant 168 content test was 1.4%.

[0065] The average of the results of six tests was taken as the final test result. The actual measured contents of antistatic agent 1800 were 14.8 wt%, antioxidant 1010 were 20.2 wt%, and antioxidant 168 were 19.5 wt%.

[0066] Example 3

[0067] Same as Example 1, except that citric acid is replaced with 2-hydroxysuccinic acid and ethyl acetate is replaced with acetone.

[0068] The average of the results of six tests was taken as the final test result. The actual measured contents of antistatic agent 1800 were 25.6 wt%, antioxidant 1010 were 51.9 wt%, and antioxidant 168 were 22.2 wt%.

[0069] Comparative Example 1

[0070] (1) At room temperature, 2.5000 g of citric acid and 50.0 mL of acetic anhydride were mixed in 450.0 mL of ethyl acetate to obtain a derivatization solution;

[0071] Mix 0.2000g of antistatic agent 1800 with 25.0mL of derivatizing solution and keep in a 30℃ water bath for 1h to obtain a clear and transparent antistatic agent 1800 standard sample test solution.

[0072] (2) The antistatic agent 1800 standard sample was mixed with the mobile phase methanol at a 1:1 ratio, and then subjected to liquid chromatography at a detector wavelength of 300 nm and a mobile phase flow rate of 1.2 mL / min. The test results are as follows: Figure 5 As shown.

[0073] Depend on Figure 5 It can be seen that when extracting spectra at wavelengths of 220nm, 280nm, 340nm, and 400nm, the expected peak positions of antistatic agent 1800 in Example 1 could not be obtained with chromatographic peaks higher than the quantitation limit of the chromatographic instrument, so effective quantitative analysis could not be performed.

[0074] Comparative Example 2

[0075] (1) At room temperature, 5g of citric acid and 100.0mL of acetic anhydride were mixed in 400.0mL of ethyl acetate to obtain a derivatization solution;

[0076] Mix 0.2000g of antistatic agent 1800 with 25.0mL of derivatizing solution and keep in a 90℃ water bath for 2h to obtain a dark brown opaque antistatic agent 1800 standard sample test solution.

[0077] (2) The antistatic agent 1800 standard sample was mixed with a mobile phase of methanol-water solution (methanol volume fraction of 80%) at a ratio of 1:2. The mixture was then subjected to liquid chromatography at a detector wavelength of 280 nm and a mobile phase flow rate of 1.0 mL / min. The test results are as follows: Figure 6 As shown.

[0078] Depend on Figure 6 It can be seen that, in Example 1, the expected peak position of antistatic agent 1800 is different from that in the test results of Comparative Example 2, where there are multiple peaks, making it impossible to perform effective qualitative and quantitative analysis.

[0079] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for testing the content of compound additives, characterized in that, The method includes the following steps: (1) The compound additive is mixed with the derivatizing solution and a colorimetric reaction is carried out at 50-80℃ to obtain the test solution; wherein the compound additive includes amine antistatic agents and antioxidants; The amine antistatic agent is selected from N,N-dihydroxyethyl octadecylamine and / or octadecylamine polyoxyethylene (2) ether; the method for preparing the derivatized liquid includes mixing an acid and an anhydride in a solvent to obtain the derivatized liquid; Wherein, the acid is selected from citric acid and / or 2-hydroxysuccinic acid; the anhydride is selected from one or more of propionic anhydride, acetic anhydride, citralic anhydride, maleic anhydride, and phthalic anhydride; (2) The test solution is analyzed by high performance liquid chromatography to obtain the content of amine antistatic agent and antioxidant; The solvent is selected from one or more of ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, and tetrahydrofuran; The ratio of the acid, acid anhydride and solvent used is 1g: 1-100mL: 30-500mL; The ratio of the compound additive to the derivative solution is 1g:10-150mL.

2. The test method according to claim 1, wherein, The antioxidant is selected from one or more of antioxidant 1010, antioxidant 168, antioxidant 1076, and antioxidant 626.

3. The test method according to claim 1, wherein, The acid is citric acid; And / or, the solvent is ethyl acetate and / or acetone.

4. The test method according to claim 1, wherein, The acid anhydride is acetic anhydride.

5. The test method according to claim 1, wherein, The ratio of acid, anhydride and solvent used is 1g: 10-30mL: 80-180mL.

6. The test method according to claim 1, wherein, The ratio of the compound additive to the derivative solution is 1g:50-100mL.

7. The test method according to claim 1, wherein, The reaction temperature for the colorimetric reaction is 60-70℃.

8. The test method according to claim 7, wherein, The reaction time for the colorimetric reaction is 0.5-4 hours.

9. The test method according to claim 8, wherein, The reaction time for the colorimetric reaction is 1-2 hours.

10. The test method according to claim 1, wherein, The detector in the high-performance liquid chromatograph is an ultraviolet absorption detector with a wavelength of 220-400 nm. And / or, the chromatographic column in the high performance liquid chromatography is selected from a reversed-phase chromatographic column.

11. The test method according to claim 10, wherein, Detector wavelength: 275-325nm; And / or, the chromatographic column in the high performance liquid chromatography is a reversed-phase C18 column.

12. The test method according to claim 1, wherein, The elution method in the high performance liquid chromatography is isocratic elution, and the flow rate of the mobile phase is 0.4-1.8 mL / min; And / or, the mobile phase is selected from one of methanol, isopropanol, methanol aqueous solution, and isopropanol aqueous solution.

13. The test method according to claim 12, wherein, The elution method in the high-performance liquid chromatography is isocratic elution, and the flow rate of the mobile phase is 0.8-1.4 mL / min; And / or, the mobile phase is methanol or an aqueous methanol solution.

14. The test method according to claim 12 or 13, wherein, The volume ratio of the test liquid to the mobile phase is 1:0.5-3.

15. The test method according to claim 14, wherein, The volume ratio of the test liquid to the mobile phase is 1:1-2.

16. The test method according to claim 1, wherein, The content of amine antistatic agents and antioxidants was calculated using the external standard method.

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