Method for determining components in LLM-105 synthetic reaction system by using liquid chromatography
By using a C18 capillary column and specific mobile phase conditions in liquid chromatography to separate DAPO, NDAPO, and LLM-105, the problems of difficult separation and inaccurate testing in the prior art are solved, and a simple and accurate component determination is achieved.
Patent Information
- Application Number
- CN202511910225.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-17
- Publication Date
- 2026-01-27
AI Technical Summary
Existing high-performance liquid chromatography (HPLC) methods for detecting LLM-105 are difficult to effectively separate DAPO, NDAPO, and LLM-105 when measuring nitration reaction solutions. Furthermore, the acid in the reaction solution reacts with methanol, affecting the chromatogram and leading to inaccurate test results.
Liquid chromatography was performed using a C18 capillary column, a specific mobile phase, and detection conditions (such as pH, flow rate, and mobile phase ratio). DAPO, NDAPO, and LLM-105 were separated by the chromatographic column, and the concentration of each component was calculated using the area normalization method.
It achieves effective separation and accurate determination of DAPO, NDAPO and LLM-105, with simple and reproducible results, and is suitable for production control.
Smart Images
Figure CN121410159A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of instrumental analysis technology and relates to a method for determining the components in the synthesis reaction system of 2,6-diamino-3,5-dinitropyrazine-1-oxide using liquid chromatography. Background Technology
[0002] 2,6-Diamino-3,5-dinitropyrazine-1-oxide (LLM-105), with the molecular formula C4H4N6O5 and a molecular weight of 216.04, appears as bright yellow needle-like crystals. It has a boiling point of 891.2℃ and a density of 1.913 g / cm³. 3 It has a heat of formation of -12 kJ / mol, is insoluble in common organic solvents, slightly soluble in water, but soluble in dimethyl sulfoxide and acids. LLM-105 has higher energy than TATB and good thermal stability; it is also a relatively insensitive energetic material. Due to its excellent overall performance, it can be used as a detonator or main charge in certain special-purpose weapons, such as earth-penetrating weapons requiring overload resistance, replacing TATB.
[0003] LLM-105 can be synthesized by nitration of 2,6-diaminopyrazine-1-oxide (DAPO) in fuming nitric acid and concentrated sulfuric acid. The main synthesis principle is as follows:
[0004] .
[0005] The above reaction system mainly involves three substances: DAPO, 2,6-diamino-3-nitropyrazine-1-oxide (NDAPO), and LLM-105.
[0006] The existing high-performance liquid chromatography (HPLC) method for detecting LLM-105 involves dissolving LLM-105 in water and using methanol as the mobile phase. However, when measuring the nitration reaction solution, three substances and byproducts are present simultaneously, making separation difficult. Furthermore, the acid in the reaction solution reacts with methanol, affecting the chromatogram. Therefore, there is an urgent need for a convenient and accurate method for determining LLM-105. Summary of the Invention
[0007] The purpose of this invention is to provide a method for determining the components in the LLM-105 synthesis reaction system using liquid chromatography. This method can effectively separate DAPO, NDAPO, and LLM-105 involved in the synthesis process, and the results are accurate and the operation is simple.
[0008] The technical solution for achieving the objective of this invention is as follows:
[0009] The specific steps for determining the components in the LLM-105 synthesis reaction system using liquid chromatography are as follows:
[0010] A C18 capillary column (4.6 × 250 mm) was used as the chromatographic column. The column temperature was set at 30 ± 5 °C, and the UV detector wavelength was 254 nm. The mobile phase flow rate was set at 0.5–1 mL / min. A salt solution containing 5 mmol / L sodium heptanesulfonate and 20 mmol / L potassium dihydrogen phosphate at pH 2.5 was prepared. V… 乙腈 V 水 Equilibrate with a mobile phase of 25:75, followed by V 乙腈 V 盐溶液 The mobile phase of 25:75 was used to test the LLM-105 synthesis reaction system solution to be tested. DAPO, NDAPO and LLM-105 in the LLM-105 synthesis reaction system solution to be tested were separated by chromatographic column.
[0011] Furthermore, the equilibration time is 60 minutes.
[0012] Furthermore, the volume of the LLM-105 synthesis reaction system solution to be tested is 1~1.5mL.
[0013] Furthermore, it also includes determining the content of each component, specifically: calculating the peak area of DAPO, NDAPO, or LLM-105, substituting it into the fitting curve of molar concentration and peak area of the liquid phase established by the corresponding standard solution, and using the area normalization method to calculate the concentration of DAPO, NDAPO, or LLM-105 in the solution of the LLM-105 synthesis reaction system to be tested.
[0014] Furthermore, the fitting curve formula for the molar concentration of DAPO and the peak area in the liquid phase is y = 2.287 × 10⁻⁶. 6 x+94.406, where x is the molar concentration of DAPO and y is the peak area of the liquid phase.
[0015] Furthermore, the fitting curve formula for the molar concentration of NDAPO and the peak area in the liquid phase is y = 1.092 × 10⁻⁶. 6 x+40.624, where x is the molar concentration of NDAPO and y is the peak area of the liquid phase.
[0016] Furthermore, the fitting curve formula for the molar concentration of LLM-105 and the peak area of the liquid phase is y = 5.632 × 10⁻⁶. 6 x-50.362, where x is the molar concentration of LLM-105 and y is the peak area of the liquid phase.
[0017] Compared with the prior art, the present invention has the following advantages:
[0018] (1) The present invention uses liquid chromatography to determine the components of the LLM-105 synthesis reaction system. This method is simple, easy to operate, and accurate.
[0019] (2) Using the method of the present invention, the raw materials, intermediate products and the components to be tested can be completely separated, the content of LLM-105 can be accurately determined, and the content of DAPO and NDAPO can also be detected, which makes it easier to understand the production status of the product and the accuracy of the analysis results is higher.
[0020] (3) The present invention uses the liquid chromatography area normalization method to determine the content of DAPO, NDAPO and LLM-105. It has good reproducibility, high precision and advantages such as convenient operation, speed and production control. Attached Figure Description
[0021] Figure 1 To adopt V 乙腈 V 盐溶液 The sample solution chromatogram during the synthesis of LLM-105 was determined using a mobile phase of 25:75.
[0022] Figure 2 To adopt V 甲醇 V 水 The chromatogram of the sample solution during the synthesis of LLM-105 was determined using a mobile phase of 3:7.
[0023] Figure 3 To adopt V 乙腈 V 水 The chromatogram of the sample solution during the synthesis of LLM-105 was determined using a mobile phase of 3:7.
[0024] Figure 4 To adopt V 乙腈 V 水的甲酸溶液 The chromatogram of the sample solution during the synthesis of LLM-105 was determined using a mobile phase of 3:7.
[0025] Figure 5 This is the external standard curve for DAPO.
[0026] Figure 6 This is the external standard curve for LLM-105.
[0027] Figure 7 This is the external standard curve for NDAPO. Detailed Implementation
[0028] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. Unless otherwise specified in the embodiments, conditions are performed according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available products.
[0029] The liquid chromatograph used in the following examples is a Wukong K2025 high performance liquid chromatograph.
[0030] Example 1
[0031] This embodiment examines the solvent and amount used in the test solution.
[0032] LLM-105 is insoluble in common organic solvents, slightly soluble in water, but soluble in dimethyl sulfoxide and acids. However, due to the high polarity of dimethyl sulfoxide, water was chosen as the solvent.
[0033] Take 100 ml of water and add 5 mg, 10 mg, and 20 mg of LLM-105 respectively. The results showed that when 20 mg of LLM-105 was added, a small amount of LLM-105 remained undissolved. Therefore, an aqueous solution of 5-10 mg / ml of LLM-105 was chosen.
[0034] Example 2
[0035] This embodiment examines the effects of liquid chromatography using different mobile phases.
[0036] Method 1: The mobile phase is V 甲醇 V 水 =3:7, UV wavelength 254nm, column temperature 30℃, mobile phase flow rate 1ml / min.
[0037] Method 2: The mobile phase is V 乙腈 V 水 =3:7, UV wavelength 254nm, column temperature 30℃, mobile phase flow rate 1ml / min.
[0038] Method 3: The mobile phase is V 乙腈 V 水的甲酸溶液 The ratio of formic acid to water was 3:7, the UV wavelength was 254 nm, the column temperature was 30 °C, and the flow rate of the mobile phase was 1 ml / min. The formic acid solution in water was prepared by adding 1 / 1000 volume of formic acid to water.
[0039] Method 4: The mobile phase is V 乙腈 V 盐溶液 The column ratio was 3:7, the UV wavelength was 254 nm, the column temperature was 30 °C, and the mobile phase flow rate was 1 ml / min. The salt solution was a mixture of 5 mmol / L sodium heptanesulfonate and 20 mmol / L potassium dihydrogen phosphate with a pH of 2.5.
[0040] The chromatographic conditions were as follows: C18 column, 4.6 × 250 mm, column temperature 30℃, UV detector wavelength 254 nm, and mobile phase flow rate 1 ml / min. First, use V... 乙腈 V 水The solution was washed with a mobile phase of 25:75 for 60 min to equilibrate, and then the mobile phase was used to test the sample solution.
[0041] Test solution: Sample solution from the LLM-105 synthesis process, 1.5 mL of a mixed solution of 10 mg / ml LLM-105, 10 mg / ml DAPO, and 10 mg / ml NDAPO.
[0042] The results are as follows Figures 1-4 As shown, among the other methods, the separation effect is not good. The method with good spectral effect and stable results is method 4, that is, using V. 乙腈 V 盐溶液 =3:7 as the mobile phase.
[0043] Example 3
[0044] Test solution: 1.5 mL of 10 mg / mL LLM-105 sample solution.
[0045] The chromatographic conditions were as follows: C18 column, 4.6 × 250 mm, column temperature 30℃, UV detector wavelength 254 nm, and mobile phase flow rate 1 ml / min. A salt solution containing 5 mmol / L sodium heptanesulfonate and 20 mmol / L potassium dihydrogen phosphate at pH 2.5 was prepared. First, V... 乙腈 V 水 Wash with a mobile phase of 25:75 for 60 min to equilibrate, then use V 乙腈 V 盐溶液 The mobile phase with a ratio of 25:75 was used to test the sample solution.
[0046] The same batch of samples was tested repeatedly using the above method, and the results showed that multiple curves overlapped, indicating that the method of the present invention has good reproducibility.
[0047] Example 4
[0048] This embodiment performs quantitative external standard testing on three components.
[0049] (1) DAPO external standard method test scheme
[0050] Weigh 25.20 mg of the raw material standard into a beaker using an analytical balance with an accuracy of 0.0001 g, add water, and dilute to 100 mL. The concentration of the substance at this point is 2 × 10⁻⁶ g. -3 mol / L.
[0051] Take 1 ml, 2 ml, 5 ml, 10 ml, 12 ml, 15 ml, 20 ml, and 25 ml of the prepared solution respectively, and pour them into 25 ml volumetric flasks. Dilute with water to the mark, and mix well. At this point, the concentrations of the eight solutions are 8 × 10⁻⁶.-5 mol / L, 1.6×10 -4 mol / L, 4×10 -4 mol / L, 8×10 -4 mol / L, 9.6×10 -4 mol / L, 1.2×10 -3 mol / L, 1.6×10 -3 mol / L, 2×10 -3 mol / L.
[0052] (2) External standard method test plan for LLM-105
[0053] Weigh 10.8 mg of the raw material standard into a beaker using an analytical balance with an accuracy of 0.0001 g, add water, and dilute to 100 mL. The concentration of the substance at this point is 5 × 10⁻⁶ g. -4 mol / L.
[0054] Take 2 ml, 5 ml, 8 ml, 10 ml, 12 ml, 15 ml, 20 ml, and 25 ml of the prepared solution respectively, and pour them into 25 ml volumetric flasks. Dilute with water to the mark, and then mix well. At this point, the concentrations of the eight solutions are 4 × 10⁻⁶. -5 mol / L, 1×10 - 4 mol / L, 1.6×10 -4 mol / L, 2×10 -4 mol / L, 2.4×10 -4 mol / L, 3×10 -4 mol / L, 4×10 -4 mol / L, 5×10 -4 mol / L.
[0055] (3) External standard method test scheme for intermediates
[0056] Weigh 5.13 mg of the intermediate standard into a beaker using an analytical balance with an accuracy of 0.0001 g, add water, and dilute to 100 mL. The concentration of the substance at this point is 3 × 10⁻⁶ g. -4 mol / L.
[0057] Take 2 ml, 5 ml, 8 ml, 10 ml, 12 ml, 15 ml, 20 ml, and 25 ml of the prepared solution respectively, and pour them into 25 ml volumetric flasks. Dilute with water to the mark, and then mix well. At this point, the concentrations of the eight solutions are 2.4 × 10⁻⁶. -5 mol / L, 6×10 -5 mol / L, 9.6×10 -5 mol / L, 1.2×10-4 mol / L, 1.44×10 -4 mol / L, 1.8×10 -4 mol / L, 2.4×10 - 4 mol / L, 3×10 -4 mol / L.
[0058] (4) Liquid phase testing methods
[0059] A C18 capillary column (4.6 × 250 mm) was used as the chromatographic column. The column temperature was 30℃, the UV detector wavelength was 254 nm, and the mobile phase flow rate was 1 ml / min. A salt solution containing 5 mmol / L sodium heptanesulfonate and 20 mmol / L potassium dihydrogen phosphate at pH 2.5 was prepared. First, V... 乙腈 V 水 Wash with a mobile phase of 25:75 for 60 min to equilibrate, then use V 乙腈 V 盐溶液 The mobile phase with a ratio of 25:75 was tested against the standard solution.
[0060] Plot a scatter plot with molar concentration on the x-axis and peak area of the liquid phase on the y-axis, and fit a straight line to the plot. The fitting results are shown in [the figure]. Figure 5-7 Based on the fitted curve, the external standard formula for DAPO is y = 2.287 × 10⁻⁶. 6 x+94.406, the external standard formula for LLM-105 is y=1.092×10 6 x + 40.624, the external standard formula for NDAPO is y = 5.632 × 10 6 x-50.362.
Claims
1. A method for determining the components in an LLM-105 synthesis reaction system using liquid chromatography, characterized in that, The specific steps are as follows: A C18 capillary column (4.6 × 250 mm) was used as the chromatographic column. The column temperature was set at 30 ± 5 °C, and the UV detector wavelength was 254 nm. The mobile phase flow rate was set at 0.5–1 mL / min. A salt solution containing 5 mmol / L sodium heptanesulfonate and 20 mmol / L potassium dihydrogen phosphate at pH 2.5 was prepared. V… 乙腈 V 水 Equilibrate with a mobile phase of 25:75, followed by V 乙腈 V 盐溶液 The mobile phase of 25:75 was used to test the LLM-105 synthesis reaction system solution to be tested. DAPO, NDAPO and LLM-105 in the LLM-105 synthesis reaction system solution to be tested were separated by chromatographic column.
2. The method according to claim 1, characterized in that, The equilibration time is 60 minutes.
3. The method according to claim 1, characterized in that, The volume of the LLM-105 synthesis reaction system solution to be tested is 1~1.5mL.
4. The method according to claim 1, characterized in that, It also includes determining the content of each component, specifically: calculating the peak area of DAPO, NDAPO or LLM-105, substituting it into the fitting curve of molar concentration and peak area of liquid phase established by the corresponding standard solution, and using the area normalization method to calculate the concentration of DAPO, NDAPO or LLM-105 in the solution of the LLM-105 synthesis reaction system to be tested.
5. The method according to claim 1, characterized in that, The fitting curve formula for the molar concentration of DAPO and the peak area in the liquid phase is y = 2.287 × 10⁻⁶. 6 x+94.406, where x is the molar concentration of DAPO and y is the peak area of the liquid phase.
6. The method according to claim 1, characterized in that, The fitting curve formula for the molar concentration of NDAPO and the peak area in the liquid phase is y = 1.092 × 10⁻⁶. 6 x+40.624, where x is the molar concentration of NDAPO and y is the peak area of the liquid phase.
7. The method according to claim 1, characterized in that, The fitting curve formula for the molar concentration of LLM-105 and the peak area of the liquid phase is y = 5.632 × 10⁻⁶. 6 x-50.362, where x is the molar concentration of LLM-105 and y is the peak area of the liquid phase.