Volt-ampere polarography for detecting content of methoxyisonitrile

Abstract

The invention relates to the technical field of analysis and detection, in particular to a voltammetry polarography for detecting the content of methoxyisonitrile, which comprises the following steps: taking concentrated hydrochloric acid, adding water to dilute, and preparing an electrolyte solution; the method comprises the following steps: diluting a to-be-detected sample containing methoxyisonitrile with water to prepare a test solution; preparing a reference solution; and measuring the content of methoxyisocyanide in the sample to be measured by adopting a voltammetry polarography method. The voltammetry polarography for detecting the content of methoxyisonitrile can effectively detect the content of methoxyisonitrile in a methoxyisonitrile raw material or stannous methoxyisonitrile for injection, and is high in analysis speed and good in repeatability.

Description

Technical Field

[0001] The invention relates to the technical field of analysis and detection, and in particular to a voltammetric polarography method for detecting the content of methoxyisocyanate. Background Art

[0002] Stannous methoxyisocyanate for injection (MIBI kit) is used to prepare technetium [ 99m Tc] methoxyisocyanate injection is a kit for MIBI, which is mainly used for the diagnosis and differential diagnosis of coronary artery disease (myocardial ischemia, myocardial infarction). The methoxyisocyanate raw material is the main raw material of the MIBI kit, which is used for complexing technetium [ 99m Tc], so the content of methoxy isocyanate directly affects the labeling effect.

[0003] The Chinese Pharmacopoeia does not yet have a method for determining the content of methoxyisonitrile. The methods for determining the content of methoxyisonitrile in the literature include ultraviolet spectrophotometry, inductively coupled plasma mass spectrometry, atomic absorption spectrophotometer and high performance liquid chromatography.

[0004] The pre-treatment process of ultraviolet spectrophotometry, inductively coupled plasma mass spectrometry, and atomic absorption spectrophotometry is complicated. The auxiliary materials in the MIBI kit need to be ashed with a muffle furnace or digested with a microwave digestion instrument. There are problems of large measurement errors and cumbersome operation. High-performance liquid chromatography can directly dissolve the sample before measurement, but it is necessary to prepare the mobile phase and balance the chromatographic column in advance, which takes a long time and is costly to measure. Therefore, it is very necessary to establish a simple and quick analytical method to detect the content of methoxyisocyanate. Summary of the invention

[0005] The invention provides a voltammetric polarography method for detecting the content of methoxy isocyanate, which is used to solve the problems of large measurement error, complicated operation, long measurement time and the like in the existing method for determining the content of methoxy isocyanate.

[0006] The present invention provides a voltammetric polarography method for detecting the content of methoxyisonitrile, comprising the following steps: Take concentrated hydrochloric acid and dilute it with water to prepare an electrolyte solution; take the sample to be tested containing methoxyisocyanate and dilute it with water to prepare a test solution; prepare a reference solution; The methoxy isonitrile content in the sample to be tested is determined by voltammetry.

[0007] Electrolyte solution plays a very important role in voltammetric polarography. It not only affects the progress of electrode reaction, but also is directly related to the quality and reliability of analysis results. The present invention selects concentrated hydrochloric acid diluent as electrolyte solution, which is consistent with the hydrochloric acid concentration in the configured test solution on the one hand. On the other hand, when concentrated hydrochloric acid diluent is electrolyte solution, divalent tin ions in MIBI kit do not produce characteristic electrode potential, while divalent tin ions in nitric acid or sulfuric acid diluent will produce characteristic electrode potential to interfere with the determination of methoxyisocyanate content. Therefore, selecting concentrated hydrochloric acid diluent as electrolyte solution is beneficial to control electrode reaction during voltammetric polarography test, improve the sensitivity and accuracy of analysis, reduce interference, improve the selectivity of analysis, stabilize polarographic waveform, and improve the accuracy of quantitative analysis of methoxyisocyanate content in the sample to be tested. The voltammetric polarography for detecting methoxyisocyanate content of the present invention is simple to operate and has a short measurement time.

[0008] Further, the electrolyte solution concentration is 1~6mol / L. Limiting the electrolyte solution concentration to the above range is more conducive to the accuracy, stability and reliability of detecting the content of methoxyisocyanate. When the electrolyte solution concentration is less than 1mol / L, in order to ensure that the concentration of hydrochloric acid in the test solution is consistent with the electrolyte solution concentration, the multiple of dilution is too large, resulting in too low potential peak height in the test solution, and large measurement error; when the concentration of the electrolyte solution is greater than 6mol / L, the small dilution multiple of the sample to be tested leads to poor solubility and the risk of corrosion of the skin and respiratory tract during the operation of the personnel. Preferably, the electrolyte solution concentration is 1~4mol / L. In some specific embodiments, the electrolyte solution concentration is 1~3mol / L.

[0009] Furthermore, the voltammetric polarography determination method is as follows: the test solution is added to the electrolyte solution, scanning with a polarograph from the initial potential and terminating at the termination potential, recording the polarographic wave height at the characteristic electrode potential, and then continuously adding a certain amount of the reference solution 2-3 times, scanning and recording the polarographic wave height according to the same method parameters after each addition of the reference solution, and calculating the content of methoxyisocyanate in the sample to be tested by the standard addition method.

[0010] Voltammetry is an electrochemical analysis method used to determine trace and ultra-trace heavy metals and other electrochemically active substances. The measurement principle is to use a three-electrode system: a working electrode, a reference electrode and an auxiliary electrode. During measurement, a variable voltage is first applied across the working electrode and the reference electrode, and the change in current between the working electrode and the auxiliary electrode is measured. Driven by the electric field force, metal ions (such as Cu) will move toward the working electrode, react on the electrode surface, be reduced to metal, form amalgam, and generate current. With the current change as the ordinate, a peak-shaped spectrum will appear, in which the voltage value corresponding to the peak vertex characterizes the type of metal ions and is a qualitative basis, and the current value corresponding to the peak vertex characterizes the concentration of metal ions and is a quantitative basis. This method has the advantages of a wide range of application, a wide range of component content that can be measured, high accuracy, good reproducibility, strong anti-interference performance, and continuous measurement.

[0011] Further, the initial potential is -150mV to 50mV; the termination potential is -(350 to 550)mV; and the characteristic electrode potential is -(160 to 340)mV. In the first specific embodiment, the initial potential is -50mV; the termination potential is -400mV; and the characteristic electrode potential is -250mV. In the second specific embodiment, the initial potential is -150mV; the termination potential is -550mV; and the characteristic electrode potential is -340mV. In the third specific embodiment, the initial potential is 50mV; the termination potential is -350mV; and the characteristic electrode potential is -160mV.

[0012] Further, in the voltammetric method, the potential step length is 4-6 mV, the pulse amplitude is 20-30 mV, the scanning speed is 3-8 mV / s, and the size of the mercury drop is 3-5 au. In a specific embodiment, in the voltammetric method, the potential step length is 5 mV, the pulse amplitude is 25 mV, the scanning speed is 5 mV / s, and the size of the mercury drop is 4 au.

[0013] Further, the calculation formula of the content of methoxy isocyanate is: ×100%, wherein W1 is the Cu determination value, V is the volume of the diluted sample to be tested, and W2 is the weight of the sample to be tested or the labeled value of methoxyisocyanate in the sample to be tested. When the sample to be tested is a methoxyisocyanate raw material, W2 is the weight of the sample to be tested; when the sample to be tested is a MIBI kit, W2 is the labeled value of methoxyisocyanate in the sample to be tested.

[0014] Further, in the voltammetric determination method, the working electrode is a multi-mode electrode (MME), the detection parameter is anodic dissolution, and the operation mode is a dropping mercury electrode (DME) or a spinning mercury electrode (SMDE).

[0015] Further, the method for preparing the test solution is as follows: take the sample to be tested and add concentrated hydrochloric acid to dissolve directly or add 4 to 6 mol / L hydrochloric acid solution to heat in a water bath for 3 to 8 minutes, then dilute with water to prepare the test solution. In the process of preparing the test solution, the sample to be tested is pre-treated with concentrated hydrochloric acid or 4 to 6 mol / L hydrochloric acid solution. The purpose of the pre-treatment is to destroy the structure of methoxyisocyanate and release copper ions. Finally, the methoxyisocyanate raw material or MIBI kit is diluted with water to a certain concentration as the test solution.

[0016] Further, the reference solution is obtained by diluting the copper standard solution with water; preferably, the concentration of the reference solution is 100-300 μg / mL. Preferably, the concentration of the reference solution is 150-250 μg / mL. In a specific embodiment, the concentration of the reference solution is 200 μg / mL.

[0017] Furthermore, the sample to be tested includes one or both of the methoxyisocyanurate raw material and the MIBI kit.

[0018] The present invention provides a voltammetric polarography method for detecting the content of methoxyisocyanate, which can effectively detect the content of methoxyisocyanate in a methoxyisocyanate raw material or a MIBI kit, with fast analysis speed and good repeatability. According to the 2020 edition of the Chinese Pharmacopoeia "9101 Analytical Method Validation Guidelines", methodological validation of specificity, linearity and range, repeatability and accuracy was carried out, proving that this method has good stability and reliability, and can be used for the determination and control of methoxyisocyanate content. The establishment of this analytical method realizes the effective detection of the content of methoxyisocyanate in a methoxyisocyanate raw material or a MIBI kit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 This is the spectrum of the auxiliary material solution of Experimental Example 1 of the present invention.

[0021] Figure 2 This is the spectrum of the reference solution of Example 1 of the present invention.

[0022] Figure 3 This is the spectrum of the test solution of Example 1 of the present invention.

[0023] Figure 4 This is a graph showing the linearity and range of Example 1 of the present invention.

[0024] Figure 5 This is a graph showing the determination of the methoxyisocyanate content in Example 1 of the present invention.

[0025] Figure 6 This is a graph showing the determination of the methoxyisocyanate content in Example 2 of the present invention.

[0026] Figure 7 This is the spectrum of the determination of the methoxyisocyanate content in Example 3 of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1

[0029] This embodiment provides a voltammetric polarography method for detecting the content of methoxy isocyanate in a methoxy isocyanate raw material and a MIBI kit, comprising the following steps: A) Preparation of electrolyte solution

[0030] Take a certain volume of concentrated hydrochloric acid and dilute it to 3 mol / L with water to prepare an electrolyte solution.

[0031] B) Preparation of test solution

[0032] Take one bottle of MIBI kit or weigh 10 mg of methoxyisocyanate raw material, add 1 mL of concentrated hydrochloric acid to dissolve directly, and dilute to 4 mL with water before measurement.

[0033] C) Preparation of reference solution

[0034] Take 1000μg / mL copper standard solution, dilute it with water to 200μg / mL and use it as reference solution.

[0035] D) Determination of methoxyisocyanate content in MIBI kit

[0036] Take 10mL of electrolyte solution and add it to the measuring cup, accurately pipette 400μL of the test solution and add it, scan with a polarograph from -50mV and stop at -400mV, record the polarographic wave height when the electrode potential is -250mV, then add 50μL of reference solution twice continuously, scan and record the polarographic wave height with the same method parameters after each addition of the reference solution, and calculate the content of methoxyisocyanate in the MIBI kit by the standard addition method.

[0037] E) Determination of methoxy isocyanate content in methoxy isocyanate raw materials

[0038] Take 10 mL of electrolyte solution and add it to the measuring cup. Accurately pipette 50 μL of the test solution and add it. Scan with a polarograph from -50 mV and stop at -400 mV. Record the polarographic wave height when the electrode potential is -250 mV. Then add 50 μL of reference solution twice continuously. After each addition of the reference solution, scan with the same method parameters and record the polarographic wave height. Calculate the content of methoxyisonitrile in the methoxyisonitrile raw material by the standard addition method.

[0039] F) Calculation formula for the content of methoxy isocyanate in methoxy isocyanate raw materials

[0040] The formula is ×100%

[0041] W1: Cu measured value W2: Weight of methoxyisocyanate raw material, mg.

[0042] G) Calculation formula for the content of methoxyisocyanate in the MIBI kit

[0043] The formula is ×100%

[0044] W1: Cu measured value W2: Methoxyisocyanate labeled value, mg.

[0045] in: The working electrode is MME, the electrolyte in the test parameters is 3 mol / L hydrochloric acid solution, the detection parameter is anodic dissolution, the quantitative method is standard addition method, the operation mode is SMDE, the initial potential is -50 mV, the termination potential is -400 mV, the characteristic potential is -250 mV, the step size is 5 mV, the pulse amplitude is 25 mV, the scanning speed is 5 mV / s, and the size of the mercury drop is 4 au.

[0046] Instruments and reagents: 884 voltammetric spectrometer, Metrohm, Switzerland; XPR205 / A electronic balance, Mettler.

[0047] Copper standard solution (Northern Weiye Metrology Technology Research Institute, batch number: 20230323); concentrated hydrochloric acid (Sinopharm Chemical Reagent Co., Ltd., batch number: 20230515); Effect verification

[0048] According to the 2020 edition of the Chinese Pharmacopoeia "9101 Analytical Method Validation Guidelines", the method described in the example was validated for specificity, linearity and range, precision and accuracy, as follows: The specific configuration process of each solution in Example 1 and the experimental verification process and results of the method of the present invention are shown in Experimental Examples 1 to 4.

[0049] Experimental Example 1 Specificity

[0050] Test solution: Take 1 bottle of MIBI kit, add 1 mL of concentrated hydrochloric acid to dissolve directly, and dilute to 4 mL with water before measurement.

[0051] Reference solution: Take 1000 μg / mL copper standard solution and dilute it with water to 100 μg / mL as the reference solution.

[0052] Excipient solution: Other excipient solutions containing methoxyisocyanate are not included in the MIBI kit.

[0053] Determination method: Take 10mL of electrolyte solution and add it to the measuring cup. Accurately pipette the test solution or control solution or auxiliary material solution into it or add no solution. Use the polarograph to scan from -50mV and end at -400mV. When the electrode potential is -250mV, record the polarographic wave height to determine whether there is interference at the electrode potential of -250mV. The results are shown in Table 1. The spectrum of the auxiliary material solution is shown in Figure 1 , the reference solution spectrum is shown in Figure 2 , the sample solution spectrum is shown in Figure 3 .

[0054] Table 1 Specificity test results

[0055] Results: The electrolyte and auxiliary material solutions had no interference at the characteristic potential of copper and had good specificity.

[0056] Experimental Example 2 Linearity and Range

[0057] Copper standard solution: dilute 1000 μg / mL copper standard solution to 100 μg / mL for later use.

[0058] 50 μL, 100 μL, 150 μL, 175 μL, and 200 μL were accurately measured respectively, and the copper content was determined according to the determination method in the embodiment, and the spectrum and results were recorded. The injection volume was used as the abscissa and the potential height was used as the ordinate to make a linear regression equation. The results are shown in Tables 2 and 3, and the spectrum is shown in Table 2. Figure 4 .

[0059] Table 2 Linearity and range

[0060] Table 3 Linear equations

[0061] Conclusion: When the copper content is in the range of 0μg to 20μg, the linear regression equation is y = 1.3935x - 0.6049, and the correlation coefficient is r = 0.998, which meets the requirement of r ≥ 0.990, and the linear relationship is good.

[0062] Experimental Example 3 Repeatability Test

[0063] A 100 μg / mL copper standard solution was prepared according to the preparation method in Example 1. According to the voltammetric polarography determination steps, 7 repeated measurements were performed to determine the potential value and potential height of copper. The results are shown in Table 4.

[0064] Table 4 Repeatability

[0065] Conclusion: The peak height repeatability RSD (%) = 0.79% and the peak potential repeatability RSD (%) = 0.39% determined by the method of the present invention respectively meet the requirement of RSD (%) ≤ 3.0%, and the repeatability is good.

[0066] Experimental Example 4 Accuracy test of MIBI kit

[0067] Determination method: Take 10mL of electrolyte solution and add it to the measuring cup, accurately pipette 400μl of the test solution and add it, scan with a polarograph from -50mV and stop at -400mV, record the polarographic wave height when the electrode potential is -250mV, then add 50μl of 200μg / mL reference solution twice continuously, scan and record the polarographic wave height with the same method parameters after each addition of the reference solution, and calculate the content of methoxyisocyanate in the MIBI kit by the standard addition method, where the calculation formula for the content of methoxyisocyanate (%) in the MIBI kit is: ×100%, the determination spectrum is shown in Figure 5 .

[0068] Determination results: The contents of methoxyisonitrile in the four MIBI kits were 94.5%, 93.6%, 95.3% and 93.0%, respectively.

[0069] Conclusion: This method was used to determine 4 MIBI kits, and the recoveries of methoxyisocyanate were between 90% and 108%, indicating good accuracy.

[0070] Experimental Example 5 Accuracy Test of Methoxyisocyanate

[0071] Determination method: Determination method of methoxy isocyanate content in methoxy isocyanate raw materials

[0072] Take 10mL of electrolyte solution and add it to the measuring cup, accurately pipette 50μL of the test solution and add it, scan with a polarograph from -50mV and stop at -400mV, record the polarographic wave height when the electrode potential is -250mV, then add 50μL of 200μg / mL reference solution twice continuously, scan and record the polarographic wave height with the same method parameters after each addition of the reference solution, and calculate the content of methoxy isocyanate in the methoxy isocyanate raw material by the standard addition method, where the calculation formula of the methoxy isocyanate content (%) in the methoxy isocyanate raw material is:

[0073] ×100%.

[0074] Measurement results: Two batches of methoxyisocyanate raw materials were weighed for measurement. The contents (%) of methoxyisocyanate in batch 1 were 102.8% and 103.4%, and the contents (%) of methoxyisocyanate in batch 2 were 98.6% and 102.1%.

[0075] Conclusion: This method was used to determine 2 batches of methoxyisocyanate raw materials, and the recoveries of methoxyisocyanate were between 90% and 108%, indicating that the accuracy of the results was good.

[0076] Example 2

[0077] This embodiment provides a voltammetric polarography method for detecting the content of methoxyisocyanate in a MIBI kit, comprising the following steps: A) Preparation of electrolyte solution

[0078] Take a certain volume of concentrated hydrochloric acid, dilute it to 6 mol / L with water, and prepare an electrolyte solution.

[0079] B) Preparation of test solution

[0080] Take 1 bottle of MIBI kit, add 1 mL of concentrated hydrochloric acid to dissolve directly, and dilute to 2 mL with water before measurement.

[0081] C) Preparation of reference solution

[0082] Take 1000μg / mL copper standard solution, dilute it to 200μg / mL with water, and then use it as the reference solution.

[0083] D) Determination of methoxyisocyanate content in MIBI kit

[0084] Take 10mL of electrolyte solution and add it to the measuring cup, accurately pipette 200μL of the test solution and add it, scan with a polarograph from -150mV to -550mV, and record the polarographic wave height when the electrode potential is -340mV. Then add 50μL of the reference solution twice in succession. After each addition of the reference solution, scan and record the polarographic wave height with the same method parameters, and calculate the content of methoxyisocyanate in the MIBI kit by the standard addition method.

[0085] E) Calculation formula for the content of methoxyisocyanate in the MIBI kit

[0086] The formula is ×100%

[0087] W1: Cu measured value W2: Methoxyisocyanate labeled value, mg.

[0088] in: The working electrode is MME, the electrolyte in the test parameters is 6 mol / L hydrochloric acid solution, the detection parameter is anodic dissolution, the quantitative method is standard addition method, the operation mode is SMDE, the initial potential is -150 mV, the termination potential is -550 mV, the characteristic potential is -340 mV, the step size is 5 mV, the pulse amplitude is 25 mV, the scanning speed is 5 mV / s, and the size of the mercury drop is 4 au.

[0089] The results of the MIBI kit are shown in Figure 6 : The contents of methoxyisocyanate in two MIBI kits were 91.2% and 90.8% respectively.

[0090] Conclusion: This method was used to determine 2 MIBI kits, and the recoveries of methoxyisocyanate were between 90% and 108%. Compared with Example 1, the recoveries were lower. One possible reason is that hydrochloric acid is a strong electrolyte. When the concentration of the electrolyte increases, the degree of ionization decreases, affecting the electrochemical reaction.

[0091] Example 3

[0092] This embodiment provides a voltammetric polarography method for detecting the content of methoxyisocyanate in a MIBI kit, comprising the following steps: A) Preparation of electrolyte solution

[0093] Take a certain volume of concentrated hydrochloric acid and dilute it to 1 mol / L with water to prepare an electrolyte solution.

[0094] B) Preparation of test solution

[0095] Take 1 bottle of MIBI kit, add 1 mL of concentrated hydrochloric acid to dissolve directly, and dilute to 12 mL with water before measurement.

[0096] C) Preparation of reference solution

[0097] Take 1000μg / mL copper standard solution, dilute it to 200μg / mL with water, and then use it as the reference solution.

[0098] D) Determination of methoxyisocyanate content in MIBI kit

[0099] Take 10mL of electrolyte solution and add it to the measuring cup, accurately pipette 1200μL of the test solution and add it, scan with a polarograph from 50mV and stop at -350mV, record the polarographic wave height when the electrode potential is -160mV, then add 50μL of the reference solution twice continuously, scan and record the polarographic wave height with the same method parameters after each addition of the reference solution, and calculate the content of methoxyisocyanate in the MIBI kit by the standard addition method.

[0100] E) Calculation formula for the content of methoxyisocyanate in the MIBI kit

[0101] The formula is ×100%

[0102] W1: Cu measured value W2: Methoxyisocyanate labeled value, mg.

[0103] in: The working electrode is MME, the electrolyte in the test parameters is 1 mol / L hydrochloric acid solution, the detection parameter is anodic dissolution, the quantitative method is standard addition method, the operation mode is SMDE, the initial potential is 50 mV, the termination potential is -350 mV, the characteristic potential is -160 mV, the step size is 5 mV, the pulse amplitude is 25 mV, the scanning speed is 5 mV / s, and the size of the mercury drop is 4 au.

[0104] The results of the MIBI kit are shown in Figure 7 : The contents of methoxyisocyanate in two MIBI kits were 105.1% and 106.5% respectively.

[0105] Conclusion: This method was used to determine 2 MIBI kits, and the recoveries of methoxyisocyanate were between 90% and 108%.

[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention 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 of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A voltammetric polarography method for detecting the content of methoxy isononitrile, characterized in that: The steps include: Take concentrated hydrochloric acid and dilute it with water to prepare an electrolyte solution; take the sample to be tested containing methoxyisocyanate and dilute it with water to prepare a test solution; prepare a reference solution; The methoxy isonitrile content in the sample to be tested is determined by voltammetry.

2. The voltammetric polarography method for detecting the content of methoxy isonitrile according to claim 1, characterized in that: The concentration of the electrolyte solution is 1-6 mol / L.

3. The voltammetric polarography method for detecting the content of methoxy isonitrile according to claim 1 or 2, characterized in that: The voltammetric polarography determination method is as follows: the test solution is added to the electrolyte solution, and the polarograph is used to scan from the initial potential and terminate at the termination potential, and the polarographic wave height is recorded at the characteristic electrode potential. Then, a certain amount of the reference solution is added continuously for 2-3 times, and each time the reference solution is added, the scanning is performed according to the same method parameters and the polarographic wave height is recorded, and the content of methoxyisocyanate in the test sample is calculated by the standard addition method.

4. The voltammetric polarography method for detecting the content of methoxy isonitrile according to claim 3, characterized in that: The initial potential is -150mV to 50mV; the termination potential is -(350 to 550)mV; and the characteristic electrode potential is -(160 to 340)mV.

5. The voltammetric polarography method for detecting the content of methoxy isonitrile according to claim 3 or 4, characterized in that: In the voltammetric determination method, the potential step length is 4 to 6 mV, the pulse amplitude is 20 to 30 mV, the scanning speed is 3 to 8 mV / s, and the size of the mercury drop is 3 to 5 au.

6. The voltammetric polarography method for detecting the content of methoxy isonitrile according to claim 3, characterized in that: The calculation formula of the content of methoxyisocyanate is: ×100%, wherein W1 is the measured value of Cu, V is the volume of the diluted sample to be tested, and W2 is the weight of the sample to be tested or the labeled value of methoxyisocyanate in the sample to be tested.

7. The voltammetric polarography method for detecting the content of methoxy isonitrile according to any one of claims 1 to 6, characterized in that: In the voltammetric polarography method, the working electrode is a multi-mode electrode, the detection parameter is anodic dissolution, and the operating mode is a dropping mercury electrode or a throwing mercury electrode.

8. The voltammetric polarography method for detecting the content of methoxy isonitrile according to claim 1, characterized in that: The method for preparing the test solution is as follows: take the sample to be tested and add concentrated hydrochloric acid to dissolve it directly or add 4-6 mol / L hydrochloric acid solution to heat it in a water bath for 3-8 minutes, then add water to dilute it to prepare the test solution.

9. The voltammetric polarography method for detecting the content of methoxy isonitrile according to claim 1, characterized in that: The reference solution is obtained by diluting the copper standard solution with water; preferably, the concentration of the reference solution is 100-300 μg / mL.

10. The voltammetric polarography method for detecting the content of methoxy isonitrile according to claim 1, characterized in that: The sample to be tested includes one or both of the methoxyisocyanurate raw material and the MIBI kit.

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