Method for detecting trace amount of copper azide content

Abstract

The application discloses a kind of copper azide content trace detection method, the detection method includes: detecting copper azide content: taking the sample to be measured and inorganic acid mixed dissolution, then sequentially adding NaOH solution, buffer solution and copper nitrate solution, using ultraviolet visible spectrophotometer to measure absorbance and calculate corresponding azide radical concentration, determine the content of copper azide and cuprous azide in the sample to be measured by azide radical and copper azide content relationship model;Detect copper azide and cuprous azide: on the basis of measuring copper azide content, determine the content of copper azide and cuprous azide in the sample to be measured by azide radical and copper azide / cuprous azide content relationship model.The copper azide content trace detection method needs simple device of the application, low requirement to equipment, does not need organic solvent or color developing agent, and environmental pollution is small, and sub-milligram level copper azide used in MEMS fuze can be detected.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of detection, in particular to a micro detection method for copper azide content. BACKGROUND

[0002] With the development of weapon system to intelligent and flexible, the initiation system composed of traditional pyrotechnics is difficult to meet the requirements of micro electro mechanical system (MEMS) fuze in volume, assembly method and output performance. Copper azide has excellent initiation performance, high reliability and low limit charge, and becomes the preferred agent in micro electro mechanical system (MEMS) fuze.

[0003] However, the charge size of copper azide reaches millimeter level, and the charge mass reaches sub-milligram level. The charge size and charge mass are greatly reduced compared with traditional pyrotechnics. The existing detection standard can no longer meet the use requirements, and it is urgent to establish a detection standard corresponding to the charge size of copper azide.

[0004] At present, the methods for characterizing copper azide content in literature research mainly include inductively coupled plasma optical emission spectrometry (ICP-OES) and powder X-ray diffraction (PXRD), which are expensive and require high operating personnel.

[0005] Therefore, it is an urgent technical problem in the field to provide a simple, efficient and low-cost detection method for copper azide. SUMMARY

[0006] The present application aims to provide a method for quickly and conveniently detecting the copper azide content in the sample to be measured.

[0007] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0008] A micro detection method for copper azide content, which determines the content of copper azide and / or cuprous azide in the sample to be measured by azide.

[0009] Preferably, the concentration of azide is measured by ultraviolet visible spectrophotometry to calculate the absorbance.

[0010] Preferably, the detection method of copper azide comprises the following steps:

[0011] (1) Establishing a standard curve of absorbance and azide concentration by ultraviolet visible spectrophotometry;

[0012] (2) Dissolving the sample to be measured with acetic acid solution, then adding NaOH solution, buffer solution and copper nitrate solution in sequence, and measuring the absorbance by ultraviolet visible spectrophotometer after constant volume and uniform mixing;

[0013] (3) the absorbance is brought into a standard curve to obtain the concentration of azide radical, so as to calculate the content of cuprous azide.

[0014] Preferably, the step of the detection method of cuprous azide is:

[0015] (1) a standard curve of absorbance and azide radical concentration is established by using ultraviolet-visible spectrophotometry;

[0016] After the sample to be measured is dissolved with acetic acid solution, it is divided into two parts, a certain volume of solution is set as group A, and the remaining solution and solid are set as group B;

[0017] (2) the content of cuprous azide is measured by using ultraviolet-visible spectrophotometry for group A;

[0018] (3) after H2SO4 is added to group B and distillation, NaOH solution is used as an absorption liquid to absorb the escaping azide acid, after heating, acetic acid solution, buffer solution and copper nitrate solution are sequentially added to the absorption liquid, the volume is set, and after uniform mixing, the absorbance is measured by using ultraviolet-visible spectrophotometer, the absorbance is brought into a standard curve to obtain the concentration of azide radical, and the content of cuprous azide is calculated by using the content of cuprous azide.

[0019] Preferably, the concentration of the acetic acid solution is 0.1-2 mol / L, and the mass-volume ratio of the sample to be measured to the acetic acid solution is 1:20-50.

[0020] The concentration of the NaOH solution is 0.1-2 mol / L, and the mass-volume ratio of the sample to be measured to the NaOH solution is 1:20-50.

[0021] Preferably, the concentration of the copper nitrate solution is 0.3-2 mol / L, and the mass-volume ratio of the sample to be measured to the copper nitrate solution is 1:40-80.

[0022] The buffer solution is a mixed aqueous solution of acetic acid and sodium acetate, the concentration of acetic acid in the buffer solution is 0.1-0.5 mol / L, the concentration ratio of the acetic acid to the sodium acetate is 1:5-10, and the mass-volume ratio of the sample to be measured to the buffer solution is 1:5-20.

[0023] Preferably, the concentration of the H2SO4 solution is 0.1-2 mol / L, and the mass-volume ratio of the sample to be measured to the H2SO4 solution is 1:10-50.

[0024] Preferably, the method for establishing the standard curve is:

[0025] 1) Preparation of each standard sample: prepare a standard solution of 100 mL with a mass concentration of 50 mg / L of azide. Take 7 10 mL cuvettes, and transfer 1 mL, 1.5 mL, 2 mL, 2.5 mL, 3 mL, 3.5 mL and 4 mL of the standard solution with a mass concentration of 50 mg / L of azide into the cuvettes, respectively, then add 1 mL of a buffer solution of acetic acid-sodium acetate with a concentration of 0.1-1 mol / L, 5 mL of a copper nitrate solution with a concentration of 1 mol / L, and dilute to 10 mL with deionized water to obtain each standard sample;

[0026] 2) Determination of the relationship model between absorbance and azide concentration: shake each standard sample and let it stand for 30 min, then measure the absorbance using a UV-visible spectrophotometer to obtain the relationship formula and / or relationship curve between the absorbance and the azide concentration of each standard sample as the relationship model between absorbance and azide concentration, i.e., the standard curve.

[0027] Preferably, the copper azide content calculation formula is:

[0028]

[0029] wherein, m a is the mass content of copper azide in the sample to be measured, mg; p a is the mass concentration of azide in the detection, mg / L; n a is the dilution factor; V a is the volume of acetic acid added for dissolving solid, mL; w a is the mass fraction of azide in copper azide.

[0030] Preferably, the copper azide content calculation formula is:

[0031]

[0032] wherein, m b is the mass content of copper azide in the sample to be measured, mg; p a , p b are the total mass concentrations of azide in groups A and B, respectively, mg / L; n a , n b is the dilution factor; V b is the volume of NaOH absorption solution, mL; V cThe volume of the remaining mixed liquid for B group, mL; w b The mass fraction of azide in cuprous azide.

[0033] The application of the method to the detection of trace copper azide content.

[0034] Compared with the prior art, the present application has the following beneficial effects:

[0035] The device required by the method for detecting trace copper azide content is simple, has low requirements on equipment, does not require organic solvents or color developing agents, has little environmental pollution, and can detect the composition of sub-milligram copper azide used in MEMS fuze. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required to be used in the embodiments or the prior art description will be briefly introduced, and the drawings in the description are only examples of the embodiments of the present application.

[0037] Figure 1 The standard curve of absorbance and azide concentration obtained in Example 1 of the present application;

[0038] Figure 2 The standard curve of absorbance and azide concentration obtained in Example 2 of the present application. DETAILED DESCRIPTION

[0039] The embodiments of the present application will be described below, examples of the embodiments are shown in the accompanying drawings, the embodiments described with reference to the drawings are exemplary and are intended to explain the present application, and are not understood as limiting the present application. Example 1

[0040] A detection method of copper azide content, specifically comprising the following steps:

[0041] (1) Establishment of standard curve

[0042] Prepare 100 mL of a standard solution of azide (N3 - ) with a mass concentration of 50 mg / L, take 7 10 mL colorimetric tubes, respectively, and transfer 1 mL, 1.5 mL, 2 mL, 2.5 mL, 3 mL, 3.5 mL, and 4 mL of the standard solution of azide with a mass concentration of 50 mg / L into the tubes, then respectively and sequentially add 1 mL of an acetic acid-sodium acetate buffer solution with a concentration of 0.1 mol / L-1 mol / L, 3 mL of a copper nitrate solution with a concentration of 1 mol / L, and dilute to 10 mL with deionized water, shake and stand for 30 min;

[0043] The absorbance was measured using a UV-Vis spectrophotometer to obtain the absorbance of each standard water sample, as shown in Table 1. Based on the absorbance of each standard water sample and its corresponding azide concentration, a relationship formula and curve between absorbance and azide concentration were determined as a model for the relationship between absorbance and azide concentration. The relationship formula between absorbance and azide concentration is obtained as A = 0.03368ρ + 0.0135, where A is the absorbance and ρ is the azide concentration (mg / L). The curve showing the relationship between absorbance and azide concentration is shown in Table 1. Figure 1 As shown;

[0044] (2) Determination of copper azide content

[0045] Take 0.9337 mg of the test sample and place it in a 12 mL test tube. Add 2 mL of 2 mol / L acetic acid to the test tube and shake to dissolve for 1 hour at room temperature until the test sample changes from black to grayish-white. Transfer 0.5 mL of the mixed solution to a 10 mL stoppered colorimetric tube and add 0.5 mL of 2 mol / L NaOH solution, 1 mL of 0.1 mol / L-1 mol / L acetate-sodium acetate buffer solution, and 3 mL of 1 mol / L sodium acetate buffer solution. Copper nitrate solution was diluted to the mark with deionized water, shaken, and allowed to stand for 30 minutes. The absorbance was measured using a UV-Vis spectrophotometer. Based on the measured absorbance of the sample, the azide content corresponding to the copper azide component in the sample was determined using the obtained absorbance-azide concentration relationship model. The copper azide content in the sample was obtained according to the formula for calculating the relationship between azide and copper azide content. The measured absorbance of the water sample was 0.294. The results are shown in Table 1.

[0046] Table 1. Absorbance and Concentration Results

[0047]

[0048] The formula for calculating the copper azide content in A is as follows:

[0049]

[0050] In the formula, the mass concentration of azide is... p a The concentration was 8.33 mg / L, and the dilution factor was [missing information]. n a The volume of acetic acid is 20. V a The mass fraction of azide in copper azide is 1 mL. w a The percentage was 56.94%, and the final determination of the copper azide content in the sample was 0.2926 mg. Example 2

[0051] A method for detecting the content of copper azide and cuprous azide, specifically comprising the following steps:

[0052] (1) Establishment of standard curve

[0053] Prepare a standard solution of azide (N3 - ) with a mass concentration of 50 mg / L, 100 mL, take 7 10 mL colorimetric tubes, respectively, 1 mL, 1.5 mL, 2 mL, 2.5 mL, 3 mL, 3.5 mL, 4 mL of azide standard solution with a mass concentration of 50 mg / L, then add 1 mL of 0.1 mol / L-1 mol / L acetic acid-sodium acetate buffer solution, 3 mL of 1 mol / L copper nitrate solution, respectively, and dilute to 10 mL with deionized water, shake and stand for 30 min;

[0054] Use the ultraviolet visible spectrophotometer to measure the absorbance, and obtain the absorbance corresponding to each standard water sample, as shown in Table 2; based on the absorbance corresponding to each standard water sample and the azide concentration corresponding to each standard water sample, determine the relationship between absorbance and azide concentration as the absorbance-azide concentration relationship model; the relationship between absorbance and azide concentration is A=0.03303ρ+0.00184, where A is the absorbance, ρ is the azide content, mg / L; the relationship curve between absorbance and azide concentration is shown in Figure 2 ;

[0055] (2) Determination of copper azide and cuprous azide content

[0056] Take 0.9863 mg of the sample to be tested and put it into a 5 mL test tube, then add 1.5 mL of acetic acid with a concentration of 2 mol / L, shake and dissolve at room temperature for 1 h, and then divide the sample to be tested into group A and group B, where group A is 0.5 mL and group B is 1 mL;

[0057] Then put group A into a 10 mL colorimetric tube with a stopper, add 0.5 mL of 2 mol / L NaOH solution, 1 mL of 0.1 mol / L-1 mol / L acetic acid-sodium acetate buffer solution, and 3 mL of 1 mol / L copper nitrate solution, respectively, dilute to the mark with deionized water, shake and stand for 30 min; with the obtained absorbance-azide concentration relationship model, determine the azide concentration corresponding to the copper azide component in the sample to be tested p a .

[0058] Add 2 mL of 1 mol / L H₂SO₄ solution to group B, heat in an oil bath at 85°C for 2 h to allow azide ions to escape as azidoic acid. Use 3 mL of 2 mol / L NaOH solution as the absorption solution to absorb the escaped azidoic acid. After the azidoic acid is recovered, transfer 1 mL of NaOH absorption solution to a 10 mL stoppered colorimetric tube, then add 1 mL of 2 mol / L acetic acid solution, 1 mL of 0.1 mol / L-1 mol / L acetate-sodium acetate buffer solution, and 3 mL of 1 mol / L copper nitrate solution. Dilute to the mark with deionized water, shake, and let stand for 30 min. Measure the absorbance using a UV-Vis spectrophotometer. Based on the measured absorbance of the sample, determine the total azide ion concentration in the sample using the obtained absorbance-azidoic acid concentration relationship model. p b The absorbance of the samples measured in groups A and B were 0.143 and 0.281, respectively.

[0059] Table 2 Absorbance and Concentration Results

[0060]

[0061] The content of cuprous azide in the sample was obtained based on the model relationship between azide and cuprous azide. The calculation formulas for the content of copper azide and cuprous azide in sample B are as follows:

[0062]

[0063] The formula detects the mass concentration of azide in A and B. p a , p b The concentrations were 4.12 and 8.45 mg / L, respectively; dilution factors. n a , n b 20 and 10 respectively; acetic acid volume V a The volume of NaOH absorption liquid is 1.5 mL. V b The volume of the mixture after testing A is 3 mL; V c The mass fraction of azide in copper azide is 1 mL. w a The mass fraction of azide in cuprous azide was 56.94%. w b The percentage was 39.80%, and the final determined content of copper azide in the sample was 0.2171 mg, and the content of cuprous azide was 0.4299 mg.

[0064] Example 3

[0065] The recovery rate test results of the detection method, which specifically comprises the following steps:

[0066] (1) Recovery rate test of copper azide detection method:

[0067] Use microliter syringe to move 3-6 μL of 3 mol / L NaN3 solution and 12 μL of 1 mol / L copper nitrate solution into a 5 mL glass tube to react to obtain black brown Cu(N3)2, then add 2 mL of 2 mol / L acetic acid into the test tube, and oscillate to dissolve for 1 h at room temperature to obtain a transparent mixed solution; move 0.5 mL of the mixed solution into a 10 mL colorimetric tube with a stopper, and sequentially add 0.5 mL of 2 mol / L NaOH solution, 1 mL of 0.1-1 mol / L acetic acid-sodium acetate buffer solution, and 3 mL of 1 mol / L copper nitrate solution, dilute to the scale with deionized water, oscillate, and stand for 30 min;

[0068] Use 2 mL of deionized water to dilute an equal amount of NaN3 as a control, use the same preparation method to prepare the test solution, use a UV-visible spectrophotometer to measure the absorbance of the solution, take the control group azide concentration as the standard, and determine the recovery rate (expressed as a percentage) by comparing the azide concentration ratio between the experimental group and the control group, and the experimental results are shown in Table 3, which shows that the copper azide detection method is relatively high and can meet the basic requirements of detection.

[0069] Table 3 Recovery rate results

[0070]

[0071] (2) Recovery rate test of cuprous azide detection method:

[0072] Use a microliter syringe to move 4 μL of 3 mol / L NaN3 solution into a 5 mL glass tube, then add 2 mL of 1 mol / L H2SO4 solution into the test tube, heat at 85°C in an oil bath to make the azide escape in the form of hydrazoic acid, and use 3 mL of 2 mol / L NaOH solution as the absorption liquid to absorb the hydrazoic acid gas; move 1 mL of the NaOH absorption liquid into a 10 mL colorimetric tube with a stopper, and sequentially move 1 mL of 2 mol / L acetic acid solution, 1 mL of 0.1-1 mol / L acetic acid-sodium acetate buffer solution, and 3 mL of 1 mol / L copper nitrate solution, dilute to the scale with deionized water, oscillate, and stand for 30 min;

[0073] An equal amount of NaN3 was diluted with 3 mL of deionized water as a control, and the test solution was prepared using the same preparation method. The absorbance was measured using a UV-visible spectrophotometer. The recovery rate (expressed as a percentage) was determined by comparing the azide concentration ratio between the experimental group and the control group based on the azide concentration of the control group. The experimental results are shown in Table 4, which shows that the recovery rate of the cuprous azide detection method first increases and then decreases with increasing heating time. A heating time of 2 h can meet the accuracy requirements of the detection.

[0074] Table 4 Recovery rate results

[0075]

[0076] Example 4:

[0077] The test results of the prior art spectrophotometric method and the inductively coupled plasma optical emission spectrometry (ICP-OES) for the copper azide content are compared, which specifically includes:

[0078] (1) Test the content of each component of copper azide by inductively coupled plasma optical emission spectrometry:

[0079] A certain amount of sample to be tested was placed in a 5 mL test tube, and 2 mL of 2 mol / L acetic acid was used to dissolve the copper azide therein. All the solution was diluted to 10 mL with 1% HNO3 and labeled as solution E. Then 1 mol / L solution was added to dissolve the remaining sample, and all the solution was diluted to 10 mL with 1% HNO3 and labeled as solution F.

[0080] After preparing the analyte solution, the emission spectrum of Cu was collected at a wavelength of 324.752 nm using ICP-OES method, and the copper ion concentration in solutions E and F was measured. The corresponding copper azide and cuprous azide mass was obtained after conversion;

[0081] As a control, the content of copper azide and cuprous azide was tested by spectrophotometry according to the cuprous azide detection method, and the specific operation steps can be seen in Example 2. The component content of different samples was tested, and the results are shown in Table 5. As can be seen from the table, the relative deviation of the copper azide and cuprous azide content measured by the two methods is within 5%, which meets the error requirements of microanalysis. However, compared with inductively coupled plasma optical emission spectrometry, spectrophotometry has the advantages of rapid determination, convenient operation of the instrument, and simple operation process.

[0082] Table 5 Test results

[0083]

[0084] The above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalent features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for detecting a trace amount of copper azide content, characterized by, The detection method is to determine the content of copper azide and / or cuprous azide in the sample to be tested by azide radical; The detection method of the copper azide is: (1-1) The standard curve of absorbance and azide radical concentration is established by ultraviolet visible spectrophotometry; (1-2) After the sample to be tested is dissolved with acetic acid solution, NaOH solution, buffer solution and copper nitrate solution are added in turn, and the volume is adjusted and mixed uniformly, then the absorbance is measured by ultraviolet visible spectrophotometer; (1-3) The absorbance is brought into the standard curve to obtain the concentration of azide radical, and the content of copper azide is calculated; The detection method of the cuprous azide is: (2-1) The standard curve of absorbance and azide radical concentration is established by ultraviolet visible spectrophotometry; After the sample to be tested is dissolved with acetic acid solution, it is divided into two parts, a certain volume of solution is defined as group A, and the remaining solution and solid are defined as group B; (2-2) The content of copper azide in group A is measured by ultraviolet visible spectrophotometry; (2-3) After H2SO4 is added in group B and distilled, NaOH solution is used as the absorption liquid to absorb the escaped hydrazoic acid, after heating, acetic acid solution, buffer solution and copper nitrate solution are added in turn into the absorption liquid, the volume is adjusted and mixed uniformly, then the absorbance is measured by ultraviolet visible spectrophotometer, the absorbance is brought into the standard curve to obtain the concentration of azide radical, and the content of cuprous azide is calculated by using the content of copper azide; The specific method of establishing the standard curve of absorbance and azide radical concentration by ultraviolet visible spectrophotometry in (1-1) and (2-1) is: Different volumes of azide radical standard solution are taken, buffer solution and copper nitrate solution are added, and deionized water is used to adjust the volume to obtain each standard sample; then the absorbance of each standard sample is measured by ultraviolet visible spectrophotometer to obtain the standard curve of absorbance and azide radical concentration.

2. The method for detecting the trace amount of copper azide content according to claim 1, characterized in that, The concentration of the acetic acid solution is 0.1-2 mol / L, and the mass-volume ratio of the sample to be tested to the acetic acid solution is 1:20-50; The concentration of the NaOH solution is 0.1-2 mol / L, and the mass-volume ratio of the sample to be tested to the NaOH solution is 1:20-50.

3. The method for detecting the trace amount of copper azide content according to claim 1, characterized in that, The concentration of the copper nitrate solution is 0.3-2 mol / L, and the mass-volume ratio of the sample to be tested to the copper nitrate solution is 1:40-80; The buffer solution is a mixed aqueous solution of acetic acid and sodium acetate, the concentration of acetic acid in the buffer solution is 0.1-0.5 mol / L, and the concentration ratio of acetic acid to sodium acetate is 1:5-10; the mass-volume ratio of the sample to be tested to the buffer solution is 1:5-20.

4. The method for detecting the trace amount of copper azide content according to claim 1, characterized in that, The concentration of the H2SO4 solution is 0.1-2 mol / L, and the mass-volume ratio of the sample to be tested to the H2SO4 solution is 1:10-50.

5. The method for detecting the trace amount of copper azide content according to claim 1, characterized in that, The method for establishing the standard curve is specifically: 1) Preparation of each standard sample: prepare a standard solution of 100 mL with a mass concentration of 50 mg / L of azide; take 7 10 mL colorimetric tubes, respectively, and transfer 1 mL, 1.5 mL, 2 mL, 2.5 mL, 3 mL, 3.5 mL and 4 mL of the standard solution of 50 mg / L of azide into the tubes, then add 1 mL of a buffer solution of acetic acid-sodium acetate with a concentration of 0.1 mol / L-1 mol / L, 5 mL of a copper nitrate solution with a concentration of 1 mol / L, and dilute to 10 mL with deionized water to obtain each standard sample; 2) Determination of the absorbance-azide concentration relationship model: after oscillation, the standard samples are left to stand for 30 min, and the absorbance is measured using a UV-visible spectrophotometer to obtain the absorbance-azide concentration relationship formula and / or relationship curve of each standard sample as the absorbance-azide concentration relationship model, i.e., the standard curve.

6. The method for trace detection of copper azide content according to claim 1, characterized in that, The copper azide content calculation formula is: ； wherein, m a is the mass content of copper azide in the sample to be tested, mg; The cuprous azide content calculation formula is: a is the mass concentration of azide in the detection, mg / L; n a is the dilution multiple; V a is the volume of acetic acid added for dissolving solid, mL; w a is the mass fraction of azide in copper azide.

7. The method for trace detection of copper azide content according to claim 1, characterized in that, The cuprous azide content calculation formula is: ； Wherein, in the formula m b is the mass content of cuprous azide in the sample to be tested, mg; ​ a , ​ b is the total mass concentration of azide in group A and group B, mg / L, respectively; n a , n b is the dilution multiple; V b is the volume of NaOH absorption solution, mL; V c is the volume of the remaining mixed solution after detection A, mL; w b is the mass fraction of azide in cuprous azide.

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