Method for detecting content of copper oxide in gas generating agent by using chemical sensor

Abstract

The invention provides a method for detecting the content of copper oxide in a gas generating agent by using a chemical sensor, in the detection process of copper ions, a test solution can be complexed with the copper ions as a chemical sensor due to the coumarin compound containing a phenylhydrazone group, so that the content of copper oxide in the gas generating agent is detected. The complexing action weakens the carbon-nitrogen double bond in the coumarin compound molecule containing the phenylhydrazone group, promotes the phenylhydrazone group in the molecule to generate hydrolysis reaction to generate a corresponding aldehyde compound, and the solution emits strong green fluorescence. When the chemical sensor is used for detecting copper ions in an aqueous solution, obvious fluorescence enhancement response is shown, the detection sensitivity is high, and the detection limit is as low as 150nM; the method has ultrahigh selectivity on copper ions, almost has no interference on other common metal ions, and especially can accurately and quantitatively analyze the content and distribution of copper oxide in the gas generating agent.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental detection, and particularly to a method for detecting the content of copper oxide in a gas generant by using a chemical sensor. Background Art

[0002] The gas generant for airbags is a composite energetic material containing multiple functional components. The flow characteristics, density, surface properties, etc. of each component are different. Therefore, it is necessary to make different components fully contact through a mixing process to make the combustion reaction faster and more complete. The quality of the mixing uniformity of the agent directly affects the performance of the gas generant. Improving the mixing uniformity can maximize the gas generation efficiency. In actual production, it is necessary to select a suitable mixing method according to the physical and chemical properties such as solubility, density, and sensitivity of the gas generant and the production cost.

[0003] In the gas generant for airbags, whether as an oxidant, a composite oxidant or a catalyst, copper oxide (CuO) plays an indispensable and important role. The addition amount of copper oxide and the mixing uniformity with other components will have a crucial impact on the combustion performance of the agent, and thus affect the performance of the gas generator and the airbag. Traditional methods generally use means such as elemental analysis, scanning electron microscopy, and inductively coupled plasma atomic emission spectrometry to characterize the distribution and composite effect of each component in the gas generant. However, these methods have the disadvantages of cumbersome sample preparation, complex instrument operation, low accuracy, and inability to eliminate the interference of coexisting ions. In addition, in order to evaluate different mixing processes and mixing parameters, it is generally measured by pressure performance tests, flame tests, and residue tests after the gas generant is matched with the gas generator, which has the disadvantages of cumbersome operation, high cost, and long time consumption.

[0004] Therefore, it is of great significance to establish a simple, efficient, and accurate method for measuring the mixing uniformity of each component of the gas generant to evaluate different mixing processes. Summary of the Invention

[0005] In view of this, the present application provides a method for detecting the content of copper oxide in a gas generant by using a chemical sensor to solve the technical problems of cumbersome operation, high cost, and long time consumption in the existing methods for detecting the content of copper oxide in a gas generant.

[0006] The object of the present invention is achieved by the following technical solutions: To achieve the above technical object, the present application adopts the following technical solutions: The present invention provides a method for detecting the content of copper oxide in a gas generant by using a chemical sensor, including: S10. Gradually add different volumes of copper ion standard solution to the test solution, and measure the fluorescence intensity of the mixed solution after each addition; the test solution includes a coumarin compound containing a phenylhydrazone group. S20. Plot a standard curve based on the relationship between the copper ion concentration and the change value of the fluorescence intensity. S30. Quantitatively add the test sample solution to the test solution to obtain a reaction solution, and measure the fluorescence intensity of the reaction solution; the test sample solution is prepared by dissolving, diluting, and making up the volume of a gas generator containing copper oxide. S40. Quantitatively analyze the copper ion concentration in the test sample solution based on the standard curve and the fluorescence intensity of the reaction solution.

[0007] Preferably, the preparation method of the test solution in step S10 includes the following steps: Mix a coumarin compound containing an aldehyde group, 4-methoxyphenylhydrazine, and absolute ethanol, and carry out an anaerobic heating reflux reaction. After the anaerobic heating reflux reaction is completed, naturally cool to room temperature, and remove the absolute ethanol by vacuum distillation to obtain a crude product. Perform column chromatography separation and purification on the crude product to obtain a coumarin compound containing a phenylhydrazone group. Mix the coumarin compound containing a phenylhydrazone group, an organic solvent, and a buffer solution to obtain a test solution.

[0008] Preferably, the molar ratio of the coumarin compound containing an aldehyde group to 4-methoxyphenylhydrazine is 1:(1.2 - 2.5); the dosage ratio of the coumarin compound containing an aldehyde group to absolute ethanol is 1 g:(30 - 100) mL.

[0009] Preferably, in the anaerobic heating reflux reaction, the reaction atmosphere is an inert atmosphere, the reflux reaction temperature is 80 - 90 °C, and the reflux reaction time is 6 - 7 h.

[0010] Preferably, the organic solvent includes any one of dimethyl sulfoxide, acetonitrile, tetrahydrofuran, N,N-dimethylformamide, and acetone, and the buffer solution includes 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid.

[0011] Preferably, the concentration of the coumarin compound containing a phenylhydrazone group in the test solution is 5×10 -7 ~1×10 -5 mol / L; the volume ratio of the buffer solution to the organic solvent is (1 - 50):5, and the pH value of the buffer solution is 5.5 - 10.

[0012] Preferably, the coumarin compound containing a phenylhydrazone group includes the structure shown in formula (I): (I).

[0013] Preferably, in step S20, the change value of the fluorescence intensity corresponding to different copper ion concentrations at 490 nm is used as the ordinate, and the copper ion concentration is used as the abscissa for linear fitting to obtain a standard curve.

[0014] Preferably, step S30 further includes the following steps: Randomly sample from the same batch of gas generant pellets and grind them sufficiently to obtain a solid sample of the agent. Dissolve the solid sample of the agent in nitric acid, filter out insoluble impurities with a micro filter, and then dilute and make up the volume with deionized water in sequence to obtain a sample solution to be measured.

[0015] Successively test the fluorescence emission spectra of the reaction solution, characterize the distribution of copper elements through the change trend of the fluorescence emission spectra, and finally evaluate the mixing uniformity of each component material in the gas generant.

[0016] Preferably, after step S40, it further includes: Precisely determine the content of copper elements in the sample solution to be measured using the standard curve and compare it with the agent formula.

[0017] Beneficial effects: The present invention provides a method for detecting the content of copper oxide in a gas generant using a chemical sensor. During the detection of copper ions, the test solution contains a coumarin compound with a phenylhydrazone group, which, as a chemical sensor, can complex with copper ions. The complexation weakens the carbon-nitrogen double bond in the molecule of the coumarin compound with a phenylhydrazone group, promoting the hydrolysis reaction of the phenylhydrazone group in the molecule to generate the corresponding aldehyde compound, thereby causing the mixed solution to emit a strong green fluorescence. In addition, when the chemical sensor of the present invention is used for detecting copper ions in an aqueous solution, it shows an obvious fluorescence enhancement response, with high detection sensitivity and a detection limit as low as 150 nM; it has extremely high selectivity for copper ions, and almost no interference from other common metal ions. In particular, it can accurately quantitatively analyze the content and distribution of copper oxide in the gas generant. Description of the Drawings

[0018] Figure 1 It is a schematic flow chart of the method for detecting the content of copper oxide in a gas generant provided by the embodiment of the present application; Figure 2 It is a fluorescence titration diagram of the test solution provided by Embodiment 1 of the present invention for standard solutions of different concentrations of copper ions; Figure 3 It is a linear relationship diagram between the change value of the fluorescence intensity of the test solution provided by Embodiment 1 of the present invention at 490 nm and the copper ion concentration; Figure 4 It is an identification response diagram of the test solution provided by Embodiment 1 of the present invention for copper ions in the coexistence of common interfering ions; Figure 5 The fluorescence spectrum change trend diagram after adding the gas generant prepared by different mixing processes to the test solution provided in Embodiment 1 of the present invention to prepare the sample solution to be tested; Figure 6 The fluorescence emission spectrum after adding the gas generant prepared by the pneumatic mixing process to the test solution provided in Embodiment 1 of the present invention to the sample solution to be tested. Detailed implementation manners

[0019] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] A chemical sensor is a type of molecular device with a "reporting" function that can change its own properties according to the presence of the target analyte to be measured, thereby realizing the specific recognition and detection of guest molecules. Among them, fluorescence technology, as an emerging detection method, has the characteristics of high sensitivity, fast response speed, low detection limit, etc., and has become the mainstream in the design of chemical sensors.

[0021] In view of this, the present invention is proposed. Through ingenious molecular design and organic synthesis, a chemical sensor with excellent performance is obtained to realize the rapid, accurate and highly sensitive detection of the copper oxide content in the gas generant. By testing the copper oxide content in different parts of the reagent, the influence of different mixing processes on the material mixing uniformity is judged, and a convenient, fast and reliable evaluation method is provided for the selection of the mixing process and the setting of the mixing process parameters in actual industrial production.

[0022] Specifically, those not specified in the present invention are carried out under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments not indicating the manufacturer can be obtained as conventional products through commercial purchase.

[0023] Please refer to Figure 1 , Figure 1 which is a schematic flow chart of the method for detecting the copper oxide content in the gas generant by using a chemical sensor provided in the embodiment of the present application; wherein, the above method includes the following steps: S10, gradually adding different volumes of copper ion standard solution to the test solution, and testing the fluorescence intensity of the mixed solution after each addition; the test solution includes a coumarin compound containing a phenylhydrazone group.

[0024] Specifically, step S10 further includes: First, prepare the test solution, and its preparation method includes the following steps: Mix the coumarin compound containing an aldehyde group, 4-methoxyphenylhydrazine and absolute ethanol, and carry out an anaerobic heating reflux reaction; After the anaerobic heating reflux reaction is completed, it is naturally cooled to room temperature, and the crude product is obtained by removing absolute ethanol through vacuum distillation. The crude product is subjected to column chromatography separation and purification to obtain a coumarin compound containing a phenylhydrazone group. The coumarin compound containing a phenylhydrazone group, an organic solvent, and a buffer solution are mixed to obtain a test solution.

[0025] Specifically, the molar ratio of the coumarin compound containing an aldehyde group to 4-methoxyphenylhydrazine is 1:(1.2 - 2.5); the dosage ratio of the coumarin compound containing an aldehyde group to absolute ethanol is 1 g:(30 - 100) mL; such settings can ensure complete reaction and avoid side reactions.

[0026] Specifically, the coumarin compound containing a phenylhydrazone group includes the structure shown in the structural formula (I): (I).

[0027] Specifically, the chemical reaction equation of the anaerobic heating reflux reaction is as follows: ; Among them, the reaction atmosphere is an inert atmosphere, the reflux reaction temperature is 80 - 90 °C, and the reflux reaction time is 6 - 7 h.

[0028] Furthermore, the coumarin compound containing an aldehyde group and some intermediates in the reaction process may have certain oxidizing or reducing properties and may react with oxygen in the air, resulting in a decrease in the purity and yield of the product. In an inert atmosphere (such as nitrogen, argon, etc.), these unnecessary oxidation reactions can be avoided, ensuring that the reaction proceeds in a purer environment, thereby improving the selectivity of the reaction and the quality of the product.

[0029] Furthermore, the reflux reaction temperature of 80 - 90 °C can provide sufficient energy for the reaction, enabling the coumarin compound containing an aldehyde group to react fully with 4-methoxyphenylhydrazine. If the temperature is too low, the reaction rate will be very slow, possibly resulting in incomplete reaction; if the temperature is too high, some side reactions may be triggered, such as the decomposition of the compound, etc. On the other hand, the boiling point of absolute ethanol is about 78 °C, and 80 - 90 °C is close to or slightly higher than the boiling point of ethanol, which is conducive to forming a stable reflux state, enabling the substances in the reaction system to be fully mixed, and improving the uniformity and efficiency of the reaction.

[0030] Furthermore, if the reaction time is too short, the coumarin compounds containing aldehyde groups may not fully react with 4-methoxyphenylhydrazine, resulting in a low product yield. If the reaction time is too long, not only will time and energy be wasted, but the product may also undergo further reactions to form some impurities, reducing the purity of the product. A reaction time of 6 - 7h has been experimentally verified to ensure a good reaction effect while minimizing side reactions and maintaining the product yield.

[0031] Specifically, the organic solvent includes any one of dimethyl sulfoxide, acetonitrile, tetrahydrofuran, N,N-dimethylformamide, and acetone, and the buffer solution includes 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES).

[0032] Specifically, the volume ratio of the buffer solution to the organic solvent is (1 - 50):5, and the pH value of the buffer solution is 5.5 - 10. Among them, an appropriate volume ratio of the buffer solution to the organic solvent can ensure that the coumarin compounds containing phenylhydrazone groups are fully dissolved in the mixed system and participate in subsequent possible reactions. The organic solvent can dissolve the compound, while the buffer solution can maintain the chemical environment of the system stable. In the range of pH value from 5.5 to 10, the coumarin compounds containing phenylhydrazone groups can maintain a relatively stable structure, reducing decomposition or structural changes caused by the acid-base environment. For example, if the acidity is too strong (pH value below 5.5), the phenylhydrazone group may be protonated, affecting the fluorescence properties of the compound; if the alkalinity is too strong (pH value above 10), side reactions such as hydrolysis of the coumarin structure may occur.

[0033] Specifically, the concentration of the coumarin compounds containing phenylhydrazone groups in the test solution is 5×10 -7 ~1×10 -5 mol / L. Among them, this concentration range is within the optimal sensitivity range for fluorescence detection. Coumarin compounds themselves have fluorescence characteristics. If the concentration is too high, the fluorescence intensity may be too high, exceeding the linear detection range of the instrument, resulting in inaccurate measurement results; if the concentration is too low, the fluorescence signal is too weak, easily interfered by background noise, and accurate and reliable detection data cannot be obtained. Within this concentration range, the fluorescence intensity can show a good linear relationship with the compound concentration, facilitating the accurate analysis of the content change of the compound by measuring the fluorescence intensity.

[0034] Specifically, the filler for column chromatography is silica gel or Al2O3; the eluent for column chromatography is a mixed solution of dichloromethane, ethyl acetate, and methanol, and the volume ratio of the three is: (5 - 10):1:(0.1 - 0.5).

[0035] In one embodiment, the test solution containing the coumarin compounds containing phenylhydrazone groups is obtained through the following steps: Prepare a solution with a concentration range of 1×10 -4 ~1×10-1 A mother liquor of a coumarin compound containing a phenylhydrazone group at a concentration of mol / L, and then the mother liquor of the coumarin compound containing a phenylhydrazone group is diluted to 5×10 -7 ~1×10 -5 mol / L with a buffer solution and an organic solvent to obtain a test solution.

[0036] Specifically, the organic solvent can be dimethyl sulfoxide, acetonitrile, tetrahydrofuran (THF), N,N-dimethylformamide, acetone, etc., and the present invention is not limited thereto; the buffer solution can be 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) buffer solution, and the pH value of the buffer solution is 5.5-10.

[0037] Furthermore, in the test solution, the volume ratio range of the buffer solution to the organic solvent is (1-50):5.

[0038] Secondly, different volumes of a copper ion standard solution are gradually added dropwise to the test solution, mixed evenly, and its emission spectrum is measured using a fluorescence spectrophotometer, and the fluorescence intensity of the mixed solution after each addition is measured.

[0039] Specifically, the preparation process of the copper ion standard solution is as follows: Weigh a certain mass of analytical pure copper salt, add deionized water to dissolve it fully to obtain a copper ion standard solution; the analytical pure copper salt can be CuCl2 and Cu(NO3)2, etc., and the present invention is not limited thereto.

[0040] Specifically, during the process of measuring the emission spectrum of the mixed solution of the copper ion standard solution with different concentration gradients and the test solution using a fluorescence spectrophotometer, the excitation wavelength is 410 nm.

[0041] The detection process in step S10 is as follows: The carbonyl group and nitrogen atom in the coumarin compound (I) containing a phenylhydrazone group can complex with copper ions. The complexation weakens the C=N double bond in the compound (I), and then it is more favorable for the attack of water molecules, promoting the hydrolysis reaction of the compound (I) to generate an aldehyde compound (II), and the solution emits strong green fluorescence. The specific process is as follows: .

[0042] The key technology of the present invention lies in that, compared with the keto carbonyl group, the aldehyde group compound has less steric hindrance, which is more conducive to the nucleophilic attack of 4-methoxyphenylhydrazine, and the reaction yield of the target compound (I) is greatly improved. The complexation of copper ions with the phenylhydrazone group in compound (I) weakens the C=N bond, which is more conducive to the subsequent hydrolysis reaction and significantly improves the detection sensitivity. Generally speaking, due to the heavy metal quenching effect of copper ions, it is somewhat challenging to construct a fluorescence-enhanced copper ion sensor. Here, however, by utilizing the complexation of copper ions to induce the hydrolysis reaction of phenylhydrazone compounds to generate aldehyde compounds with stronger fluorescence, a new idea and method for constructing a fluorescence-enhanced copper ion sensor are provided.

[0043] S20. Draw a standard curve according to the relationship between the copper ion concentration and the change value of fluorescence intensity.

[0044] Specifically, step S20 further includes: Among them, by testing the fluorescence spectral response of the test solution of the coumarin compound containing the phenylhydrazone group to the standard copper ion solution, a standard curve of the copper ion concentration and the fluorescence intensity change is obtained: taking the change value of the fluorescence intensity corresponding to the mixed solution with different copper ion concentrations at 490 nm as the ordinate and the copper ion concentration as the abscissa for linear fitting, a standard curve of the copper ion concentration and the change value of fluorescence intensity is obtained.

[0045] S30. Quantitatively add the test sample solution to the test solution to obtain a reaction solution, and test the fluorescence intensity of the reaction solution; the test sample solution is prepared by dissolving, diluting, and making up the volume of a gas generator containing copper oxide.

[0046] Specifically, step S30 further includes: First, prepare the test sample solution, and its preparation method is as follows: Randomly sample from the same batch of gas generator pellets and grind them sufficiently to obtain a solid sample of the agent; Dissolve the solid sample of the agent in nitric acid, filter out the insoluble impurities with a micro filter, and then dilute and make up the volume with deionized water to obtain the test sample solution.

[0047] Secondly, quantitatively add the test sample solution to the test solution to obtain a reaction solution, and test the fluorescence intensity of the reaction solution.

[0048] In one embodiment, step S30 further includes: Provide 5 gas generator agents produced by two different mixing processes with the same formula, and then randomly sample 2 times from different parts of each agent, a total of 20 solid samples. Weigh a certain mass of the solid sample, grind it sufficiently, dissolve it in nitric acid, filter out the insoluble impurities with a micro filter, and dilute and make up the volume with deionized water to obtain the test sample solution.

[0049] Add the above-mentioned sample solution to be measured to the test solution, mix evenly, and use a fluorescence spectrophotometer to measure its emission spectrum, and measure the fluorescence emission intensity of the sample solution to be measured at 490 nm with different addition amounts; characterize the distribution of copper elements through the change trend of the fluorescence spectrum, and characterize the uniformity of the mixing of each component material in the gas generant.

[0050] S40. Quantitatively analyze the concentration of copper ions in the sample solution to be measured according to the standard curve and the fluorescence intensity of the reaction solution.

[0051] Specifically, the step S40 further includes: Determine the concentration of copper ions in the sample solution to be measured according to the standard curve of copper ions. If the concentration of copper ions in the sample solution to be measured is too high, it needs to be diluted with deionized water to the copper ion concentration range applicable to the standard curve first.

[0052] Preferably, after the step S40, it further includes: Use the standard curve to accurately measure the content of copper elements in the sample solution to be measured and compare it with the pharmaceutical formulation.

[0053] The present invention will be further described below in conjunction with specific embodiments.

[0054] Example 1: This Example 1 provides a method for detecting the content of copper oxide in a gas generant by using a chemical sensor, and its specific steps include the following: Step (1) Prepare a coumarin compound (I) containing a phenylhydrazone group: Under a nitrogen atmosphere, dissolve a coumarin aldehyde compound (322 mg, 1.2 mmol) and 4-methoxyphenylhydrazine (345 mg, 2.5 mmol) in 10 mL of absolute ethanol, and then heat and reflux at 90 o °C for 7 hours. After the reaction is completed, cool to room temperature naturally. Remove the solvent ethanol by rotary evaporation to obtain a crude product. Use a mixed solution with a volume ratio of dichloromethane / ethyl acetate / methanol = 35 / 5 / 1 as the eluent, separate and purify by silica gel column chromatography, and then dry in a vacuum drying oven to obtain the target compound (I).

[0055] The nuclear magnetic resonance hydrogen spectrum structural characterization results of the above target compound (I) are as follows: 11H NMR (500 MHz, CDCl3): 7.48 - 7.51 (1H, t), 7.23 - 7.24 (1H, m), 7.01 (s, 2H), 6.84 - 6.88 (d, 1H), 6.53 (2H, s), 6.36 (1H, s), 3.42 (3H, s), 2.90 - 2.97 (4H, q), 2.19 - 2.23 (4H, t), 2.00 - 2.03 (4H, t); 13 13C NMR (125 MHz, CDCl3): 156.1, 140.1, 138.0, 133.1, 132.1, 129.9, 129.5, 124.4, 120.2, 115.1, 112.1, 45.4, 42.4, 41.9, 36.5, 28.0; MS(ESI), m / z (rel. / Cal.): [M + H] + 389.8 / 390.2.

[0056] Step (2) Preparation of the test solution: Prepare a HEPES buffer solution with a concentration of 10 mM and a pH of 7.1; prepare a THF solution of compound (I) to obtain a first solution with a concentration of 1×10 -4 mol / L. Take 1 mL of the above first solution and place it in a 10 mL volumetric flask, and make up the volume with 9 mL of HEPES buffer solution to obtain a test solution with a concentration of 1×10 -5 mol / L (the volume ratio of THF to HEPES buffer solution is 1:9).

[0057] Step (3) Preparation of the copper ion standard solution: Prepare an aqueous solution of Cu(NO3)2 with a concentration of 3.0×10 -3 mol / L using deionized water.

[0058] Step (4) Plot the standard curve of copper ion concentration and fluorescence intensity: Take 3 mL of the test solution prepared in step (2) and place it in a quartz cuvette. At room temperature, with an excitation wavelength of 410 nm, measure its emission spectrum using a fluorescence spectrophotometer. Then, successively add aqueous solutions of Cu(NO3)2 prepared in step (2) with volumes (unit: μL) of 0, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0, 3.0, 5.0, and 5.0 to the test solution (neglecting the influence on the total volume), and continuously measure the fluorescence spectra under the same conditions.

[0059] Please refer to Figure 2 , Figure 2Fluorescence titration graph of the test solution provided in Example 1 of the present invention for copper ions with different concentrations; Figure 2 In it, the titration curves from bottom to top at 490 nm successively represent the fluorescence spectra of the system when the copper ion concentrations (unit: 10 -5 mol / L) in the system are 0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.5, 3.0, and 3.5 respectively.

[0060] From Figure 2 it can be seen that as the copper ion concentration increases, the fluorescence emission intensity gradually increases, and the maximum emission peak blue-shifts from 520 nm to 490 nm. Moreover, when the copper ion concentration in the system is only 2×10 -6 mol / L, there is a very obvious change in the fluorescence intensity compared with the blank solution; when the copper ion concentration increases to 3.5×10 -5 mol / L, the fluorescence intensity reaches the peak, and the fluorescence intensity at 490 nm increases by 470 times, and the fluorescence quantum yield of the solution increases from 0.05 to 0.67.

[0061] Please refer to Figure 3 , Figure 3 Linear relationship graph between the change value of the fluorescence intensity of the test solution provided in Example 1 of the present invention at 490 nm and the copper ion concentration; It can be seen from Figure 3 that in the concentration range of 0 - 35 μM, the change of the fluorescence spectrum shows a good linear relationship with copper ions (R 2 = 0.9986). The simulated linear equation is y = -0.38852 + 134.5417*x (y represents the fluorescence intensity at 490 nm, x represents the copper ion concentration, unit: 10 -5 mol / L), indicating that the detection method provided by the present invention can achieve accurate quantitative analysis of copper ions. According to the formula: detection limit = , the detection limit of this complex is calculated to be as low as 150 nM. Among them, represents the standard deviation of the fluorescence intensity of the blank solution measured ten times, and k represents the slope of the fitting curve in Figure 3 . It can be seen that the target compound (I) in Example 1 of the present invention can achieve highly sensitive detection of copper ions.

[0062] Step (5) Repeatedly prepare the test solution: Prepare a HEPES buffer solution with a concentration of 10 mM and a pH of 7.1; Prepare a THF solution of compound (I) to obtain a first solution with a concentration of 1×10 -4 mol / L. Take 1 mL of the above first solution and place it in a 10 mL volumetric flask, and make up the volume with 9 mL of HEPES buffer solution to obtain a concentration of 1×10 -5The test solution of mol / L (the volume ratio of THF to HEPES buffer solution is 1:9).

[0063] Step (6) Prepare aqueous solutions of different cations: Prepare deionized aqueous solutions of NaNO3, KNO3, LiCl, AgNO3, MgSO4, MnSO4·2H2O, Zn(NO3)2·6H2O, Ni(NO3)2·6H2O, Pb(NO3)2, Ba(NO3)2, Ca(NO3)2·4H2O, CoCl2·6H2O, CdSO4·8H2O, Fe(NO3)3·9H2O, Al(NO3)3·9H2O, and Cr(NO3)3·9H2O with deionized water. The cation concentration of the above different deionized aqueous solutions is all 1×10 -2 mol / L.

[0064] Step (7) Selectivity experiment for copper ions: Take 3 mL of the test solution prepared in step (5) and place it in a quartz cuvette; then, sequentially add 30 μL of the aqueous solutions of each different cation prepared in step (6) to the test solution; at room temperature, with an excitation wavelength of 410 nm, use a fluorescence spectrophotometer to measure its emission spectrum. Then continue to add a copper ion solution with a concentration of 3.0×10 -5 mol / L, with an excitation wavelength of 410 nm, and use a fluorescence spectrophotometer to measure its emission spectrum.

[0065] Please refer to Figure 4 , Figure 4 which is the recognition response diagram of the test solution provided in Example 1 of the present invention for copper ions in the coexistence of common interfering ions; among them, the ordinate represents the fluorescence intensity at 490 nm, and the abscissa represents the aqueous solutions of various different cations (interfering ions) with a concentration of 10×10 -5 mol / L, and the aqueous solutions of various different cations (interfering ions plus copper ions) with added copper ions. By comparing Figure 4 the heights of the bar graphs, it can be seen that the fluorescence spectral response of the compound (I) in Example 1 of the present invention to other common metal ions is much smaller than that to copper ions. Moreover, even under the condition of coexistence of interfering ions, the compound (I) has a good response to copper ions. The error bars represent the standard deviation of three measurements, indicating that Example 1 of the present invention can achieve highly selective detection of copper ions.

[0066] Step (8) Repeat the preparation of the test solution: Prepare a HEPES buffer solution with a concentration of 10 mM and a pH of 7.1; prepare a THF solution of compound (I) to obtain a first solution with a concentration of 1×10 -4 mol / L. Take 1 mL of the above first solution and place it in a 10 mL volumetric flask, and make up the volume with 9 mL of HEPES buffer solution to obtain a concentration of 1×10-5 The test solution (volume ratio of THF to HEPES buffer solution is 1:9) of mol / L.

[0067] Step (9) Prepare the sample solution to be tested: Using the traditional mechanical mixing process and the pneumatic mixing process respectively, continuously produce 5 batches of materials in the same state according to the same formula of the gas generator, and take 2 parallel samples from the materials of the same batch. A total of 20 solid samples are obtained, and the mass of each is 100 mg. After thoroughly grinding the solid samples, dissolve them in 10 mL of nitric acid, filter out the insoluble impurities with a micro filter, and dilute with deionized water by 10 times to obtain the sample solution to be tested (the sample to be tested of the gas generator).

[0068] Step (10) Test the fluorescence emission spectrum of the sample solution to be tested: Take 200 μL of the sample solution to be tested from different batches respectively, add them into 10 mL of the test solution, shake well, and measure their fluorescence emission spectra.

[0069] Please refer to Figure 5 , Figure 5 , which is the trend chart of the fluorescence spectrum change after adding the sample solution to be tested prepared by the gas generator produced by different mixing processes to the test solution provided in Example 1 of the present invention; among them, as Figure 5 shown, for the 10 sample solutions to be tested of the gas generator using the pneumatic mixing process, the change trend of the fluorescence intensity is relatively small, indicating that the fluctuation of the copper element distribution is small, that is, the mixing uniformity and the compounding effect of each component of this agent are better. Relatively speaking, for the gas generator column produced by the mechanical mixing process, the change of the fluorescence intensity is larger, indicating that the fluctuation of the copper element distribution is larger, that is, the mixing uniformity of this process and the consistency of the product are poor.

[0070] Please refer to Figure 6 , Figure 6 , which is the fluorescence emission spectrum after adding the sample solution to be tested of the gas generator produced by the pneumatic mixing process to the test solution provided in Example 1 of the present invention. Among them, as Figure 6 shown, the fluorescence intensities of 10 sample solutions to be tested produced by the pneumatic mixing process are tested respectively, and the average value of the change of the fluorescence intensity is 185. The corresponding copper ion concentration in the standard curve is 1.42×10 -5 mol / L, and the calculated mass of copper oxide is 5.6 mg, which is basically the same as the content of copper oxide 5.5% added in the formula, indicating that this method can accurately determine the content of copper oxide in the gas generator sample.

[0071] The present invention discloses a method for detecting copper oxide in a gas generant by using a chemical sensor, which includes the following steps: First, a compound containing a phenylhydrazone group can undergo a hydrolysis reaction under the catalysis of copper ions to generate a corresponding carbonyl compound, resulting in the solution changing from almost non-fluorescent to a strong green fluorescence, enabling specific recognition and detection of copper ions.

[0072] When the compound described in the present invention is used as a fluorescence sensor for detecting copper ions in an aqueous solution, it exhibits an obvious fluorescence enhancement response, with high detection sensitivity and a detection limit as low as 150 nM; using a standard curve, the accurate content and distribution of copper oxide in the gas generant agent can be accurately determined, thereby evaluating the quality of the mixing process; it has extremely high selectivity for copper ions, and other common metal ions have almost no interference.

[0073] Therefore, the detection method provided by the present invention can conveniently and quickly detect the accurate content of copper oxide in the gas generant, and characterize the change trend of the copper oxide content in different parts of the agent through the fluctuation of the fluorescence intensity, and further judge the influence of different mixing processes on the material mixing uniformity, providing a convenient, quick and reliable evaluation method for the selection of the mixing process and the setting of the mixing process parameters in actual industrial production.

[0074] In summary, the method for detecting copper oxide in a gas generant by using a chemical sensor provided by the present invention can achieve high-sensitivity and high-selectivity detection of copper ions, especially can determine the content and distribution of copper oxide in the gas generant, and thereby evaluate the uniformity of the agent mixing process and the compounding effect of each component of the agent, providing a convenient, quick and reliable evaluation method for the selection of the mixing process and the setting of the mixing process parameters in actual industrial production.

[0075] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for detecting the copper oxide content in a gas generant using a chemical sensor, characterized in that, Including: S10, gradually adding different volumes of a copper ion standard solution to a test solution, and testing the fluorescence intensity of the mixed solution after each addition is completed; The test solution includes a coumarin compound containing a phenylhydrazone group; S20, plotting a standard curve based on the relationship between the copper ion concentration and the change value of the fluorescence intensity; S30, quantitatively adding a sample solution to be tested to the test solution to obtain a reaction solution, and testing the fluorescence intensity of the reaction solution; the sample solution to be tested is prepared by dissolving, diluting, and making up the volume of a gas generator containing copper oxide; S40, quantitatively analyzing the copper ion concentration in the sample solution to be tested according to the standard curve and the fluorescence intensity of the reaction solution.

2. The method for detecting the content of copper oxide in a gas generant using a chemical sensor according to claim 1, characterized in that, The preparation method of the test solution in the S10 step includes the following steps: Mixing a coumarin compound containing an aldehyde group, 4-methoxyphenylhydrazine, and absolute ethanol, and performing an anaerobic heating reflux reaction; After the anaerobic heating reflux reaction is completed, naturally cooling to room temperature, and removing absolute ethanol by vacuum distillation to obtain a crude product; Performing column chromatography separation and purification on the crude product to obtain the coumarin compound containing a phenylhydrazone group; Mixing the coumarin compound containing a phenylhydrazone group, an organic solvent, and a buffer solution to obtain the test solution.

3. The method for detecting the content of copper oxide in a gas generant by using a chemical sensor according to claim 2, wherein The molar ratio of the coumarin compound containing an aldehyde group to 4-methoxyphenylhydrazine is 1:(1.2 - 2.5); the dosage ratio of the coumarin compound containing an aldehyde group to absolute ethanol is 1 g:(30 - 100) mL.

4. The method for detecting the copper oxide content in a gas generant by using a chemical sensor according to claim 2, wherein In the anaerobic heating reflux reaction, the reaction atmosphere is an inert atmosphere, the reflux reaction temperature is 80 - 90 °C, and the reflux reaction time is 6 - 7 h.

5. The method for detecting the content of copper oxide in a gas generating agent using a chemical sensor according to claim 2, characterized in that, The organic solvent includes any one of dimethyl sulfoxide, acetonitrile, tetrahydrofuran, N,N-dimethylformamide, and acetone, and the buffer solution includes 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid.

6. The method for detecting the content of copper oxide in a gas generant using a chemical sensor according to claim 5, characterized in that, The concentration of the coumarin compound containing a phenylhydrazone group in the test solution is 5×10 -7 ~1×10 -5 mol / L; the volume ratio of the buffer solution to the organic solvent is (1~50):5, and the pH value of the buffer solution is 5.5~10.

7. The method for detecting the content of copper oxide in a gas generating agent using a chemical sensor according to claim 2, characterized in that, The coumarin compound containing a phenylhydrazone group includes a structure shown in the structural formula (I): (I)。 8. The method for detecting the content of copper oxide in a gas generating agent using a chemical sensor according to claim 1, characterized in that, In the S20 step, linear fitting is performed with the change value of the fluorescence intensity corresponding to different copper ion concentrations at 490 nm as the ordinate and the copper ion concentration as the abscissa to obtain the standard curve.

9. The method for detecting the content of copper oxide in a gas generating agent by using a chemical sensor according to claim 1, characterized in that, The S30 step further includes the following steps: Randomly sampling from the same batch of gas generator pellets and thoroughly grinding to obtain a solid pharmaceutical sample; Dissolving the solid pharmaceutical sample in nitric acid, filtering to remove insoluble impurities with a microfilter, and then diluting and making up the volume with deionized water to obtain the sample solution to be tested; Successively testing the fluorescence emission spectrum of the reaction solution, characterizing the distribution of copper elements through the change trend of the fluorescence emission spectrum, and finally evaluating the mixing uniformity of each component material in the gas generator.

10. The method for detecting the content of copper oxide in a gas generant by using a chemical sensor according to claim 9, characterized in that, After the S40 step, it further includes: Precisely determining the content of copper elements in the sample solution to be tested using the standard curve, and comparing it with the pharmaceutical formulation.

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