阅读说明：本技术 一种二硝酰胺铵水溶液或固体中二硝酰胺铵的定量分析方法 (Method for quantitatively analyzing ammonium dinitramide in ammonium dinitramide aqueous solution or solid ) 是由 丛伟民 王晓东 王雅彬 夏连根 张万生 于 2019-11-22 设计创作，主要内容包括：本发明公开了一种二硝酰胺铵(ADN,NH-4N(NO-2)-2)水溶液或固体中ADN含量的定量分析方法；通过离子色谱方法检测ADN样品中硫酸根(SO-4～(2-))和硝酸根(NO-3～-)杂质的含量；通过ICP方法检测样品中金属离子含量(K～+、Na～+、Ca～(2+)、Mg～(2+))；通过甲醛-酸碱滴定方法检测样品中总铵根离子(NH-4～+)含量；根据溶液中的阴阳离子平衡,计算得到样品中二硝酰胺根离子(N(NO-2)-2～-)含量；假设N(NO-2)-2～-阴离子对应的均为NH-4～+阳离子,即可计算得到样品中ADN的含量。本发明有效避免了无市售ADN标准样品进行定量检测的问题,首创了无需ADN标准样品即可对ADN样品中ADN组分进行准确定量的分析方法,能够有效满足对ADN产品中ADN含量的定量检测要求。(The invention discloses ammonium dinitramide (ADN, NH) 4 N(NO 2 ) 2 ) Quantitative analysis method of ADN content in aqueous solution or solid; detection of sulfate radical (SO) in ADN samples by ion chromatography 4 2‑ ) And Nitrate (NO) 3 ‑ ) The content of impurities; detection of Metal ion content (K) in samples by ICP method + 、Na + 、Ca 2+ 、Mg 2+ ) (ii) a Detection of total ammonium ions (NH) in a sample by formaldehyde-acid base titration 4 + ) Content (c); calculating to obtain dinitroamide radical ion (N (NO) in the sample according to the balance of anions and cations in the solution 2 ) 2 ‑ ) Content (c); suppose N (NO) 2 ) 2 ‑ The anions correspond to each other and are NH 4 + And (4) cationic calculation to obtain the ADN content in the sample. The invention effectively avoids the problem of quantitative detection of the ADN standard sample on the market, and initiates the process of carrying out the ADN component in the ADN sample without the ADN standard sampleThe accurate quantitative analysis method can effectively meet the quantitative detection requirement on the ADN content in the ADN product.)

1. A method for the quantitative analysis of ammonium dinitramide in aqueous ammonium dinitramide solutions or solids, characterized in that it comprises the steps of:

step 1, detecting the content of nitrate and sulfate impurities in an Ammonium Dinitramide (ADN) aqueous solution or a solid sample:

(1) preparing standard stock solutions of nitrate and sulfate radicals, and preparing series of standard mixed solutions containing nitrate radicals and sulfate radicals, wherein the different series of standard mixed solutions contain nitrate radicals with different concentrations and sulfate radicals with different concentrations, and the number of the standard mixed solutions is not less than 3, and the unit is mg/L; analyzing by using an ion chromatograph, recording the peak areas of nitrate and sulfate radicals, drawing a concentration-peak area standard curve of the nitrate and sulfate radicals by using an external standard method, wherein the correlation coefficient of the standard curve is not less than 0.99, and obtaining a standard curve regression equation of the nitrate and sulfate radicals;

(2) weighing a certain amount of ADN sample to be measured (the measurement precision is at least accurate to 0.0002g), transferring the ADN sample to a volumetric flask, directly transferring the ammonium dinitramide aqueous solution to the volumetric flask or transferring the ADN solid sample after adding water to dissolve the ADN solid sample, fixing the volume with water, and shaking up to prepare a sample solution; adopting an ion chromatograph, carrying out sample injection analysis by using the same test conditions in the step 1(1), recording the peak areas of nitrate radical and sulfate radical, substituting the peak areas into the standard curve regression equation prepared in the step 1(1) to calculate the concentration of the nitrate radical and the sulfate radical in the ADN sample solution, wherein the unit is mg/L;

(3) the nitrate or sulfate content is calculated by the following formula:

in the formula: the nitrate or sulfate content of the ω -ADN sample; rho is the concentration of nitrate or sulfate ions in the sample solution, mg/L; v is the volume of the sample solution, L; m-weighing the mass of the ADN sample, g;

and 2, detecting the content of metal ion impurities.

(1) Preparing standard stock solutions of potassium, calcium, sodium and magnesium metal ions, preparing standard mixed solutions containing the potassium, calcium, sodium and magnesium metal ions, wherein different series of standard mixed solutions contain potassium with different concentrations, calcium with different concentrations, sodium with different concentrations and magnesium with different concentrations, the number of the standard mixed solutions is not less than 3, respectively introducing the series of standard mixed solutions into a plasma emission spectrometer, measuring according to an instrument measuring program, respectively drawing a standard curve by taking the concentrations of 4 metal elements as horizontal coordinates and corresponding signal intensity values as vertical coordinates, and the correlation coefficient of the standard curve is not less than 0.99;

(2) weighing a certain amount of ADN sample to be measured (the measurement precision is at least accurate to 0.0002g), transferring the ADN sample to a volumetric flask, directly transferring the ammonium dinitramide aqueous solution to the volumetric flask or transferring the ADN solid sample after adding water to dissolve the ADN solid sample, fixing the volume with water, and shaking up to prepare a sample solution; and (4) introducing the sample solution into an instrument atomization system for measurement, and checking the corresponding element concentration from the standard curve. If the element concentration in the sample exceeds the range of the standard curve, further diluting the test solution by using water to ensure that the element concentration reaches the range of the standard curve;

(3) the content of each metal impurity is calculated according to the following formula:

in the formula: omega_i-the content of the measured metal ions in the ADN sample, i being the number of the measured metal ions; rho_i-the concentration of metal ions in the sample solution in mg/L; v is the volume of the sample solution, in L; f-the factor by which the sample solution is further diluted, and if the sample solution is not further diluted, the value is1; m-weight of ADN sample, unit g;

step 3, detecting the content of total ammonium ions;

(1) weighing a certain amount of ADN sample to be measured (the measurement precision is at least accurate to 0.0002g), directly using ammonium dinitramide aqueous solution or using an ADN solid sample after adding water for dissolving, adding a certain amount of neutral formaldehyde solution, wherein the amount of formaldehyde in the formaldehyde solution is 5-100 times (preferably 10-30 times) of the amount of ADN in the ADN sample, standing for 3-10 minutes, adding 1-2 drops of phenolphthalein indicator, titrating with 0.1-0.5M sodium hydroxide standard solution, titrating the solution until pink is a titration end point, recording the volume of consumed sodium hydroxide, simultaneously performing a blank test, and parallelly measuring for at least 2 times;

(2) calculation of results

The amount of total ammonium ion species in the solution per unit mass is calculated as follows:

in the formula: n is_NH4 ⁺-the amount of total species of ammonium ions in the solution per unit mass, mol/g; c_NaOH-sodium hydroxide standard solution concentration, mol/L; v₂-the volume of sodium hydroxide standard solution consumed at the end of the titration, L; v₁-volume of sodium hydroxide standard solution consumed for the blank test, L; m-mass of ADN solution sample weighed, g;

step 4, calculating the mass fraction of ADN in the ADN aqueous solution or the solid sample

Combining the total ammonium ion content n in the sample obtained by the measurement in the step 3_NH4 ⁺And measuring the contents of nitrate and sulfate radicals and the contents of K, Na, Ca and Mg metal ions in the sample obtained in the step 1 and the step 2, wherein the mass fraction of ADN in the ADN sample is calculated according to the following formula:

in the formula: omega_ADN-mass fraction,%, of ADN in the ADN solution sample; n is_NH4 ⁺The content of total ammonium ion substances in the solution per unit mass, mol/g; omega_NO3-mass fraction of nitrate in ADN solution sample; omega_SO4-mass fraction of sulfate groups in the ADN solution sample; omega_Na-mass fraction of sodium ions in the ADN solution sample; omega_K-mass fraction of potassium ions in the ADN solution sample; omega_Ca-mass fraction of calcium ions in the ADN solution sample; omega_Mg-mass fraction of magnesium ions in the ADN solution sample; m_NO3-molecular weight of nitrate, g/mol; m_SO4Molecular weight of sulfate, g/mol; m_ADNMolecular weight of ADN, g/mol; m_Na-the molecular weight of sodium ions; m_K-the molecular weight of potassium ions; m_Ca-the molecular weight of the calcium ions; m_Mg-molecular weight of magnesium ions.

2. The quantitative analysis method as set forth in claim 1, wherein:

wherein the ion chromatography conditions are: the chromatographic column is one of AS-22 or AS-23; column temperature: 20-40 ℃; gradient leaching, wherein the flow rate of leaching solution is 0.80-1.50 mL/min; a chemical suppressor; a conductivity detector.

3. The quantitative analysis method as set forth in claim 1, wherein: preferably, the chromatography column is AS-22 is a chromatography column;

the temperature of the chromatographic column is 20-40 ℃, and preferably 30 ℃.

4. A quantitative analysis method according to claim 1, 2 or 3, characterized in that:

the ion chromatography elution mode is a gradient elution mode, and an elution liquid A: 4.5mmol Na₂CO₃+1.4mmol NaHCO₃An aqueous solution; and (3) eluent B: acetonitrile (chromatographically pure); the ion chromatography gradient elution detection procedure is as follows:

the initial stage is as follows: introducing 100% of leacheate A from 0min to 10min to 15 min;

an intermediate stage, namely starting to introduce 60-90% V/V eluent A and 40-10% V/V eluent B from the end of the initial stage to the 20-30 min;

the next stage: after the intermediate stage is finished: introducing 100% of leacheate A; after 35 min-50 min: the measurement procedure is stopped;

the flow rate of the leaching solution is 0.80-1.50mL/min, and preferably 1.20 mL/min.

5. The quantitative analysis method as set forth in claim 4, wherein:

the suppressor is a chemical suppressor, and the preferable model of the suppressor is AMMS 3004 mm;

the detector is a conductivity detector;

the volume of the sample injected each time in the method is 25 mu L.

6. A quantitative analysis method according to claim 1, 2 or 3, characterized in that:

the concentration range of nitrate radical in the mixed standard solution is 0.1-500mg/L, and the concentration range of sulfate radical is 0.1-500 mg/L; the concentration range of nitrate radical in the ADN sample solution is 0.1-500mg/L, and the concentration range of sulfate radical is 0.1-500 mg/L.

Technical Field

The invention relates to a method for quantitatively analyzing ammonium dinitramide in an ammonium dinitramide aqueous solution and a solid. The method is mainly used for quantitative analysis and detection of the ADN content in ADN aqueous solution and ADN solid products.

Background

Ammonium dinitramide is a novel high-energy ionic liquid energy material, and has the advantages of high energy, stable and rapid decomposition, complete combustion without residue, clean exhaust, large gas evolution, low signal characteristic, no toxicity and the like. Can be used as a green propulsion material to be applied to the field of auxiliary power of civil aerospace and aviation, and meets the application requirement of non-toxicity. Meanwhile, the composite material can be used as a gas generator material, an ionic liquid explosive, a solid explosive, a low-characteristic signal high-energy oxidant, a synthetic raw material of other high-energy ionic liquid and the like, and has high application value.

The most common synthesis method of ADN raw material is mixed acid nitration, potassium sulfamate or ammonium sulfamate is nitrated by mixed nitric acid and sulfuric acid, then ammonia gas is used for neutralization and separation and purification to obtain ADN aqueous solution, although the ADN aqueous solution prepared by the method is purified by active carbon, a small amount of ammonium nitrate, ammonium sulfate and metal ion (mainly K, Na, Ca and Mg) impurities are still inevitably mixed, wherein the ammonium nitrate and ammonium sulfate impurities are from the neutralization of mixed nitric acid and sulfuric acid and ammonia gas, and the K, Na, Ca and Mg metal ions are from water used in the preparation process.

The quantitative determination method of ADN includes empirical density method, UV spectrophotometer method, ion chromatography, etc., but all of the above methods require a high-purity ADN standard sample with a known accurate content as a reference, but there is no commercial ADN standard sample at present. Therefore, the method for analyzing the ADN content can be directly and quantitatively detected without a standard sample, and has very important significance for quality guarantee, application and popularization of ADN products.

Disclosure of Invention

In order to meet the requirement of ADN accurate quantification in ADN aqueous solution and solid products, the invention provides a quantitative analysis method for the content of ammonium dinitramide in ammonium dinitramide aqueous solution or solid prepared by a mixed acid nitration method, and the content of ADN components in the ammonium dinitramide aqueous solution or solid can be accurately quantified without an ADN standard sample. Impurities introduced by the mixed acid nitration method are limited to ammonium nitrate, ammonium sulfate and metal ions of K, Na, Ca and Mg, and the ADN content in the sample can be calculated only by accurately detecting the impurities and balancing the anions and the cations.

In order to realize the technical task, the invention adopts the following technical scheme to realize:

a method for quantitatively analyzing ammonium dinitramide in an aqueous solution and a solid of ammonium dinitramide prepared by a mixed acid nitration method specifically comprises the following steps:

step 1, detecting the content of nitrate and sulfate impurities in Ammonium Dinitramide (ADN) aqueous solution and solid samples:

(1) preparing standard stock solutions of nitrate and sulfate radicals, and preparing series of standard mixed solutions containing nitrate radicals and sulfate radicals, wherein the different series of standard mixed solutions contain nitrate radicals with different concentrations and sulfate radicals with different concentrations, and the number of the standard mixed solutions is not less than 3, and the unit is mg/L; analyzing by using an ion chromatograph, recording the peak areas of nitrate and sulfate radicals, drawing a concentration-peak area standard curve of the nitrate and sulfate radicals by using an external standard method, wherein the correlation coefficient of the standard curve is not less than 0.99, and obtaining a standard curve regression equation of the nitrate and sulfate radicals;

(2) weighing a certain amount of ADN sample to be measured (the measurement precision is at least accurate to 0.0002g), transferring the ADN sample to a volumetric flask, directly transferring the ammonium dinitramide aqueous solution to the volumetric flask or transferring the ADN solid sample after adding water to dissolve the ADN solid sample, fixing the volume with water, and shaking up to prepare a sample solution; adopting an ion chromatograph, carrying out sample injection analysis by using the same test conditions in the step 1(1), recording the peak areas of nitrate radical and sulfate radical, substituting the peak areas into the standard curve regression equation prepared in the step 1(1) to calculate the concentration of the nitrate radical and the sulfate radical in the ADN sample solution, wherein the unit is mg/L;

wherein the ion chromatography conditions are: the chromatographic column is one of AS-22 or AS-23; column temperature: 20-40 ℃; gradient leaching, wherein the flow rate of leaching solution is 0.80-1.50 mL/min; a chemical suppressor; a conductivity detector.

Preferably, the chromatography column is AS-22.

The temperature of the chromatographic column is 20-40 ℃, preferably 30 ℃, and in such a temperature range, sample injection is carried out under the same other conditions, so that the influence on the aspects of the separation degree, the peak shape, the symmetry degree and the like of a sample is small, and good separation can be realized.

The ion chromatography elution mode is a gradient elution mode, and an elution liquid A: 4.5mmol Na₂CO₃+1.4mmol NaHCO₃An aqueous solution; and (3) eluent B: acetonitrile (chromatographically pure); the ion chromatography gradient elution detection procedure is as follows:

the initial stage is as follows: introducing 100% of leacheate A from 0min to 10min to 15 min;

an intermediate stage, namely starting to introduce 60-90% V/V eluent A and 40-10% V/V eluent B from the end of the initial stage to the 20-30 min;

the next stage: after the intermediate stage is finished: introducing 100% of leacheate A; after 35 min-50 min: the measurement procedure is stopped;

the eluent adopts gradient elution, organic solvent is added in the eluent, the organic solvent has the functions of adjusting the selectivity of the ion exchange process and changing the retention characteristic of the separation column on the analyte, so that the elution sequence and the separation degree are changed, 10 to 40 percent of acetonitrile is introduced into the middle section procedure of the gradient elution, and a large amount of N (NO) in the ADN aqueous solution can be obtained₂)₂ ^-(DN^-) The anions are eluted as soon as possible, and the analysis time is greatly shortened.

The flow rate of the leaching solution is 0.80-1.50mL/min, and preferably 1.20 mL/min.

The suppressor is a chemical suppressor, and the electric suppressor is not suitable for being used under the condition that the leacheate contains more than 30% of organic solvent, and when the sample contains higher-concentration organic solvent, the suppression capability is reduced, the baseline is floated, and the normal peak is influenced. The chemical inhibitor has the advantages of quick balance, low background noise, firmness and durability, and normal operation at the working temperature of 40 ℃ from room temperature, and can normally work in the presence of 40% of organic solvent, so the chemical inhibitor is adopted in the invention, and the preferred model of the inhibitor is AMMS 3004 mm.

The detector is a conductivity detector. The volume of the sample injected each time in the method is 25 mu L.

The concentration range of nitrate radical in the mixed standard solution is 0.1-500mg/L, and the concentration range of sulfate radical is 0.1-500 mg/L. The concentration range of nitrate radical in the ADN sample solution is 0.1-500mg/L, and the concentration range of sulfate radical is 0.1-500 mg/L.

(3) The nitrate or sulfate content is calculated by the following formula:

in the formula: the nitrate or sulfate content of the ω -ADN sample; rho is the concentration of nitrate or sulfate ions in the sample solution, mg/L; v is the volume of the sample solution, L; m-weight the mass of ADN sample, g.

And 2, detecting the content of metal ion impurities.

(1) Preparing standard stock solutions of potassium, calcium, sodium and magnesium metal ions, preparing standard mixed solutions containing the potassium, calcium, sodium and magnesium metal ions, wherein different series of standard mixed solutions contain potassium with different concentrations, calcium with different concentrations, sodium with different concentrations and magnesium with different concentrations, the number of the standard mixed solutions is not less than 3, respectively introducing the series of standard mixed solutions into a plasma emission spectrometer, measuring according to an instrument measuring program, respectively drawing a standard curve by taking the concentrations of 4 metal elements as horizontal coordinates and corresponding signal intensity values as vertical coordinates, and the correlation coefficient of the standard curve is not less than 0.99;

(2) weighing a certain amount of ADN sample to be measured (the measurement precision is at least accurate to 0.0002g), transferring the ADN sample to a volumetric flask, directly transferring the ammonium dinitramide aqueous solution to the volumetric flask or transferring the ADN solid sample after adding water to dissolve the ADN solid sample, fixing the volume with water, and shaking up to prepare a sample solution; and (4) introducing the sample solution into an instrument atomization system for measurement, and checking the corresponding element concentration from the standard curve. If the element concentration in the sample is beyond the range of the standard curve, the test solution is further diluted by water to ensure that the element concentration reaches the range of the standard curve.

(3) The content of each metal impurity is calculated according to the following formula:

in the formula: omega_i-the content of the measured metal ions in the ADN sample, i being the number of the measured metal ions; rho_i-the concentration of metal ions in the sample solution in mg/L; v is the volume of the sample solution, in L; f is the further dilution factor of the sample solution, if the sample solution is not further diluted, the value is 1; m-weight of ADN sample, unit g.

And 3, detecting the content of total ammonium ions.

(1) The total ammonium ion content can be measured by the following method: adding neutral formaldehyde into the ADN solution, and reacting ammonium ions in the solution with the formaldehyde to generate hexamethylenetetramine, strong acid and water:

4NH₄ ⁺+6HCHO＝(CH₂)₆N₄+4H⁺+6H₂O

neutralizing the strong acid generated by the reaction with sodium hydroxide solution, the amount of sodium hydroxide consumed being equal to the total amount of ammonium groups in the ADN aqueous solution, n_NH4 ⁺(the sum of the amounts of ammonium species in ADN, nitrate and sulfate).

The specific measurement method comprises the following steps:

weighing a certain amount of ADN sample to be measured (the measurement precision is at least accurate to 0.0002g), directly using ammonium dinitramide aqueous solution or using an ADN solid sample after adding water for dissolving, adding a certain amount of neutral formaldehyde solution, wherein the amount of formaldehyde in the formaldehyde solution is 5-100 times (preferably 10-30 times) of the amount of ADN substance in the ADN sample, standing for 3-10 minutes, adding 1-2 drops of phenolphthalein indicator, titrating with 0.1-0.5M sodium hydroxide standard solution, titrating the solution until pink is a titration end point, recording the volume of consumed sodium hydroxide, simultaneously performing a blank test, and parallelly measuring for at least 2 times.

(2) Calculation of results

The amount of total ammonium ion species in the solution per unit mass is calculated as follows:

in the formula: n is_NH4 ⁺-the amount of total species of ammonium ions in the solution per unit mass, mol/g; c_NaOH-sodium hydroxide standard solution concentration, mol/L; v₂-the volume of sodium hydroxide standard solution consumed at the end of the titration, L; v₁-volume of sodium hydroxide standard solution consumed for the blank test, L; m-mass of sample ADN solution weighed, g.

Step 4, calculating the mass fraction of ADN in ADN aqueous solution or ADN in solid

The ADN aqueous solution or solid product prepared by the mixed acid nitration method mainly comprises ADN, water, nitrate radical, sulfate radical and metal ions (mainly Na, K, Ca and Mg ions). The cation in the solution can be considered as a metal ion (K)⁺、Na⁺、Ca^{2 +}、Mg²⁺) And ammonium ion (NH)₄ ⁺) The anion is dinitramide radical ion (DN)^-，N(NO₂)₂ ^-) Nitrate ion (NO)₃ ^-) And sulfate ion (SO)₄ ^2-)。

According to the balance of anions and cations, the following can be obtained:

n_NH4 ⁺+n_Na ⁺+n_K ⁺+2n_Ca ²⁺+2n_Mg ²⁺＝n_NO3 ^-+2n_SO4 ^2-+n_DN ^-

the derivation can be found:

n_DN ^-＝n_NH4 ⁺+n_Na+n_K+2n_Ca+2n_Mg-(n_NO3 ^-+2n_SO4 ^2-)

the total content n of ammonium ions is obtained by the measurement in the step 3_NH4 ⁺Separately measuring the dissolution by step 1 and step 2The contents of nitrate radical and sulfate radical in the solution and the contents of K, Na, Ca and Mg metal ions in the solution are calculated, and the corresponding amount of substances in the solution per unit mass is calculated. And calculating the mass fraction of the dinitramide radical by calculating the quantity of the dinitramide radical in the solution in unit mass, and calculating the mass fraction of the dinitramide radical by assuming that all dinitramide radical anions correspond to ammonium cations.

The mass fraction of ADN in the ADN solution sample was calculated as follows:

in the formula: omega_ADN-mass fraction,%, of ADN in the ADN solution sample; n is_NH4 ⁺The content of total ammonium ion substances in the solution per unit mass, mol/g; omega_NO3-mass fraction of nitrate in ADN solution sample; omega_SO4-mass fraction of sulfate groups in the ADN solution sample; omega_Na-mass fraction of sodium ions in the ADN solution sample; omega_K-mass fraction of potassium ions in the ADN solution sample; omega_Ca-mass fraction of calcium ions in the ADN solution sample; omega_Mg-mass fraction of magnesium ions in the ADN solution sample; m_NO3-molecular weight of nitrate, g/mol; m_SO4Molecular weight of sulfate, g/mol; m_ADNMolecular weight of ADN, g/mol; m_Na-the molecular weight of sodium ions; m_K-the molecular weight of potassium ions; m_Ca-the molecular weight of the calcium ions; m_Mg-molecular weight of magnesium ions.

According to the method, aiming at the ADN product prepared by the mixed acid nitration method, nitrate radical, sulfate radical, metal ions and ammonium ions in the product are respectively measured, the three steps are independent and have no interference, calculation is carried out according to the balance of anions and cations, the ADN content in the product can be accurately detected without a standard sample, and the measurement requirement of the ADN content in the ADN sample can be effectively met.

Drawings

FIG. 1 is a standard curve of nitrate ion in example 1.

FIG. 2 is a standard curve of sulfate ion in example 1.

Detailed Description

The following examples are provided by the inventors to further illustrate the test method:

example 1:

the method of step 1 is adopted: chromatography column AS-22; the column temperature is 30 ℃; the suppressor model is AMMS 3004 mm; a conductivity detector. The sample volume per injection was 25. mu.L.

Gradient leaching, wherein the flow rate of a leaching solution is 1.20 mL/min; eluent A: 4.5mmol Na₂CO₃+1.4mmol NaHCO₃An aqueous solution; and (3) eluent B: acetonitrile (chromatographically pure); the ion chromatography gradient elution detection procedure is as follows:

the initial stage is as follows: starting from 0min to 12min, introducing 100% of eluent A;

the middle stage, starting to introduce 70% V/V eluent A and 30% V/V eluent B from the 12 th min to the 22 th min;

the next stage: after the intermediate stage is finished: introducing 100% of leacheate A; stopping the determination process after 35 min;

the nitrate and sulfate standard curves are drawn through the ion chromatography conditions, the specific data are shown in table 1, and the standard curve graphs and the standard curve regression equations of nitrate and sulfate are respectively shown in fig. 1 and fig. 2.

TABLE 1 nitrate, sulfate Standard Curve test data

Selecting about 70 wt% ADN sample solution prepared by a mixed acid nitration method, taking about 2g of sample, transferring the sample into a 100mL volumetric flask for constant volume, and carrying out ion chromatography detection on the solution according to the determination conditions. The nitrate and sulfate concentration detection data are shown in tables 2 and 3, respectively.

TABLE 2 measurement results of nitrate concentration

TABLE 3 measurement of sulfate radical concentration

About 2g of the sample was taken by the method of step 2, transferred to a 100mL volumetric flask for constant volume, and subjected to ICP detection, and the results of the detection of the concentration of each metal ion are shown in Table 4.

TABLE 4 measurement results of Metal ion concentration

Metal ion	K	Na	Ca	Mg
					Concentration (wt-%)	0.00080	0.00011	0.00075	0.00005

It can be seen from table 4 that the metal ion content is very low and can be ignored in the calculation process.

The method of step 3 is adopted: weighing about 0.5g of ADN sample solution, adding 10mL of neutral formaldehyde solution, standing for 5 minutes, adding 1 drop of phenolphthalein indicator, titrating with 0.1011mol/L sodium hydroxide standard solution, titrating the solution until pink is used as a titration end point, recording the volume of consumed sodium hydroxide, and simultaneously carrying out a blank test. The results are shown in Table 5.

TABLE 5 measurement results of the amount of total ammonium ion species

The method of step 4 is adopted: the above data were combined and calculated, and the calculation results are shown in table 6.

TABLE 6ADN concentration calculation results

Example 2:

using the same standard curves for nitrate and sulfate radicals and regression equations as in example 1, 3 ADN sample solutions prepared by the mixed acid nitration method and having concentrations estimated to be about 10 wt%, 20 wt% and 40 wt%, respectively, were tested under the above-described measurement conditions, and the measurement results for nitrate and sulfate radicals are shown in tables 7 and 8, respectively.

TABLE 7 measurement results of nitrate concentration

TABLE 8 measurement of sulfate radical concentration

As in example 1, the metal ion content detected was extremely low and was therefore ignored.

Weighing a certain amount of ADN sample solution, adding 10mL of neutral formaldehyde solution, standing for 5 minutes, adding 1 drop of phenolphthalein indicator, titrating with 0.1011mol/L sodium hydroxide standard solution, titrating the solution until pink is used as a titration end point, recording the volume of consumed sodium hydroxide, and simultaneously performing a blank test. The results are shown in tables 9, 10 and 11.

TABLE 910% ADN test results

TABLE 1020% ADN test results

TABLE 1140% ADN test results

The method of step 4 is adopted: the above data were combined and calculated, and the calculation results are shown in tables 12, 13 and 14.

TABLE 1210% ADN calculation

TABLE 1320% ADN calculation

Table 1440% ADN calculation