CN108519370A - A kind of analysis method of manganese, silicon and potassium element in the determination graphene oxide - Google Patents

Abstract

The invention belongs to graphene oxide impurity element quantitative analysis tech, are related to a kind of analysis method measuring manganese, silicon and potassium element in graphene oxide.The present invention uses the sample treatment of electric furnace staged heating Muffle furnace calcination acid soluble oxide, using inductively coupled plasma spectrometer measurement.The present invention is tested by dissolution conditions, and co-existing element interference experiment, working curve linear test determines optimal analytical line, improves the accuracy of measurement；Method measurement range is wide, manganese element detection range 0.10%~10.0%, element silicon detection range 0.05%~1.00%, potassium element detection range 0.01%~0.20%；Method is reproducible, and the rate of recovery, precision are preferable；Show that made fixed analysis method accuracy is good by analysis results comparisons such as the analyzing of standard sample, different instrument verifications, method is stablized, and the requirement of trace element analysis is complied fully with；The method of the present invention measurement is directly quick, easy to operate, has saved a large amount of man power and materials.

Description

A kind of analysis method of manganese, silicon and potassium element in the determination graphene oxide

technical field

The invention belongs to the quantitative analysis technology of graphene oxide impurity elements, and relates to an analysis method for determining manganese, silicon and potassium elements in graphene oxide.

Background technique

Graphene, a one-atom-thick two-dimensional layer of carbon atoms, is considered the building block from which other allotropes of carbon are built. Compared with graphene, the presence of a large number of oxygen-containing functional groups in graphene oxide makes it have excellent hydrophilicity and high chemical coordination, and is easy to combine with other materials to form new nanocomposites. Manganese, silicon and potassium elements exist in graphene oxide as impurity elements, and their presence will cause graphene oxide to reunite, lose its unique two-dimensional structure, seriously affect product quality, and bring huge hidden dangers to material applications. Therefore, the establishment of an accurate and rapid quantitative analysis method for manganese, silicon and potassium in graphene oxide has important guiding significance for material engineering and industrialization. At present, there is no standard method for the quantitative analysis of graphene oxide at home and abroad. Most of the analytical methods for manganese, silicon and potassium that can be consulted are for metal materials such as steel, high-temperature alloys, and aluminum alloys. The above materials are related to the physical properties of graphene oxide. The properties, chemical properties and activities are quite different, and the above method is not suitable for the quantitative analysis of manganese, silicon and potassium in graphene oxide.

In recent years, Inductively Coupled Plasma Emission Spectroscopy (ICP-AES) has been widely used in materials, geology, metallurgy, environment, food and other fields because of its accuracy, high sensitivity, environmental protection, and manpower saving. An important means of quantitative analysis of element content. At present, there is no report on the quantitative analysis of element content in graphene oxide by using inductively coupled plasma emission spectrometry at home and abroad.

Contents of the invention

The purpose of the present invention is to provide a quantitative analysis method for the content of manganese, silicon and potassium in graphene oxide with simple pretreatment and wide analysis range, so as to solve the problem of quality evaluation in the graphene oxide preparation process.

The technical solution of the present invention: an analysis method for determining manganese, silicon and potassium in graphene oxide, characterized in that a platinum crucible is used as a container, and the temperature of graphene oxide is raised to 400°C in a stepwise manner in an electric furnace, and then a muffle furnace is used Burn at 1000±50°C to obtain residual oxides that remove the carbon matrix; after burning, the oxides are dissolved in a 20:1 mixed solution of hydrochloric acid and hydrofluoric acid, and the dissolved samples after treatment are transparent and clear, using inductive coupling Plasma spectrometer, using Mn257.610nm, Si 251.611nm, K 766.468nm as the analysis line, measured under the working condition of high-frequency incident power of 0.9kW.

The weight of the graphene oxide sample can be 0.1000g to 0.5000g according to the content of the element to be measured.

The stepwise temperature increase of the electric furnace is 100±10°C for 1 hour, 200±10°C for 2 hours, 300±10°C for 2 hours, and 400±10°C for 2 hours.

The muffle furnace is burned at 1000±50°C for at least 1 hour, and it can be appropriately increased to 2 hours depending on the oxidation of the sample.

The mixed solution of described hydrochloric acid, hydrofluoric acid is 5mL hydrochloric acid, 5 drops hydrofluoric acid.

Advantage of the present invention is:

1) The sample processing technology is one of the advantages of the invention, which is original. In the present invention, a platinum crucible is used as a container, and the temperature of the electric furnace is stepped up to remove organic reagents such as hydrazine hydrate adsorbed on the surface of graphene oxide; after the reagents are exhausted, they are placed in a muffle furnace for burning at 1000°C for 2 hours; after the carbon matrix is completely oxidized, add 5mL of hydrochloric acid, 5 drops of hydrofluoric acid. This treatment method can effectively remove the interference of residual organic reagents and carbon matrix on the experimental results, and is a prerequisite for accurate quantitative analysis of manganese, silicon and potassium in graphene oxide;

2) Through the interference test of coexisting elements, the best working conditions and analysis lines of the instrument were determined, which improved the accuracy and stability of the measurement results;

3) The detection range is wide, the detection range of manganese element is 0.10%-10.0%, the detection range of silicon element is 0.05%-1.00%, and the detection range of potassium element is 0.01%-0.20%;

4) Hydrochloric acid and nitric acid reagents use high-purity or MOS grade reagents, which are conducive to the measurement of low-content potassium elements;

5) Low-content potassium element analysis, direct measurement can get better analysis results;

6) There is no interference of coexisting elements, and the mixed configuration standard curve is used to measure the content of manganese, silicon and potassium elements at one time, which is easy and fast to operate;

7) Simultaneously process the blank sample, and deduct it when calculating the measurement result, reduce the interference introduced by the reagent and the processing process, and improve the accuracy of the analysis result;

8) Through the method re-inspection and comparison with the analysis results of other units, the comparison of the results shows that the analysis method formulated is accurate, stable, and fully meets the requirements of material analysis;

9) The application method is fast in measurement, easy to operate, and saves a lot of manpower and material resources;

10) The ICP-AES method has a wide application range, low cost of use, easy promotion and economic value.

Description of drawings

Fig. 1 is graphene oxide sample pretreatment temperature and time curve

Detailed ways

An analysis method for the determination of manganese, silicon and potassium in graphene oxide. The graphene oxide sample is heated up to 400°C in a stepwise manner in an electric furnace, and then burned at 1000±50°C in a muffle furnace to obtain the residue after removing the carbon matrix. Oxide; After burning, the oxide is dissolved in a 20:1 mixed solution of hydrochloric acid and hydrofluoric acid. After treatment, the dissolved sample is transparent and clear. It is measured by an inductively coupled plasma spectrometer. Working conditions, using Mn257.610nm, Si 251.611nm, K 766.468nm as analysis lines. The working conditions of the instrument are shown in Table 1:

Table 1 Instrument Working Conditions

project parameter project parameter High frequency, MHz 40.68 Incident power, kW 0.9 Entrance slit, μm 20 Sheath gas flow, L/min 0.2 Auxiliary air flow L/min 0.3 Sample lifting volume, mL/min 1.2 Integration time, s 2 Integral method one point Reflected power, W <10 - -

1. The specific test steps are as follows:

(1), the reagents used in the determination process are as follows:

(1.1), hydrochloric acid: ρ1.19g/mL, prepared by high-purity or sub-boiling distillation;

(1.2), nitric acid: ρ1.42g/mL, prepared by high-purity or sub-boiling distillation;

(1.3), hydrofluoric acid: ρ is about 1.15g/mL;

(1.4), sodium hydroxide: 100g/L.

(1.5), manganese standard solution A: 1.00mg/mL.

Weigh 0.5000g manganese metal (w(Mn)>99.99%), and place it in a 200mL beaker. Add 3mL of water and 3mL of nitric acid (1.2), heat to dissolve completely, and boil to drive away nitrogen oxides. Cool to room temperature, transfer to a 500ml volumetric flask, add 40mL nitric acid (1.2), dilute with water to the mark.

(1.6), silicon standard solution A: 0.50mg/mL;

Weigh 5.06g of sodium silicate (Na ₂ SiO ₃ ·9H ₂ O), put it in a 250mL polytetrafluoroethylene beaker, and dissolve it in water. Add 4mL of sodium hydroxide solution, transfer to a plastic bottle, dilute to 800mL with water, place for 72h, filter in a 1000mL volumetric flask, dilute to the mark with water, mix well, and immediately transfer to a dry plastic bottle. Its exact concentration is calibrated according to 4.9 in HB 5218.6-2004.

(1.7), silicon standard solution A: 0.10mg/mL;

Pipette 50.00mL of silicon standard solution A (1.7) into a 250mL volumetric flask, add 20mL of hydrochloric acid, dilute to the mark with water, and mix well.

(1.8), potassium standard solution A: 1.00 mg/mL.

Accurately weigh 1.907g of potassium chloride (fired at 450°C to 500°C for 2h in advance), put it in a 300mL beaker, dissolve it in water, transfer it to a 1000mL volumetric flask, dilute to the mark with water, and shake well.

(1.9), potassium standard solution B: 0.10 mg/mL.

Pipette 25.00mL potassium standard solution A (1.9) into a 250mL volumetric flask, dilute to the mark with water, and mix well.

(1.10), potassium standard solution C: 0.01mg/mL.

Pipette 25.00mL potassium standard solution B (1.10) into a 250mL volumetric flask, dilute to the mark with water, and mix well.

(2) Sampling and sample preparation: The samples for analysis are sampled according to the systematic sampling method, that is, each bag of samples in a batch of products is arranged in a certain order, and a bag is randomly selected from the first bag to the nth bag of products Sampling is carried out, and then every n-γ bag is taken for sampling. The sampling amount in each bag is the same. The samples taken are combined and mixed as samples of this batch of products. The total sampling amount is not less than 5g.

(3), sample dissolution test

Graphene oxide is highly active, but common inorganic acids cannot digest it under normal temperature and pressure, so it is difficult to transform the sample into a liquid for analysis. Graphene oxide has a large specific surface area, and graphene adsorbs a large amount of hydrazine hydrate during the oxidation process. If the heating rate is too fast, it will cause a violent reaction, and the sample will splash and cause loss. After many experiments and explorations, it was determined that the electric furnace was heated at a low temperature step by step to remove organic reagents such as hydrazine hydrate; after that, it was fired at a high temperature of 1000°C in a muffle furnace to obtain the residual oxides that removed the carbon matrix; after burning, the oxides were finally treated with 5ml hydrochloric acid, 5 Drops of hydrofluoric acid are dissolved, and the dissolved sample after treatment is transparent and clear, which can meet the requirements of spectral analysis for sample solution.

(4) Interference test of coexisting elements

Prepare a single element test solution, scan within the 0.1842nm window range near the center wavelength of 2 to 4 analytical spectral lines of each analytical element, obtain the spectral scanning patterns of the single interfering element solution, analytical element solution and reagent blank solution, and compare the spectra The images were overlaid and enlarged to study their spectral interference. The final analysis line: Mn257.610nm, Si 251.611nm, K 766.468nm

(5) Working curve linearity test

Pipette 6.00mg of Mn, 0.30mg of Si, and 0.15mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 6.00% Mn, 0.30% Si, 0.15% K, which is the highest point in the standard curve.

Pipette 4.00mg of Mn, 0.20mg of Si, and 0.05mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 4.00% Mn, 0.20% Si, 0.05% K, which is used as control point 1 in the standard curve.

Pipette 2.00mg of Mn, 0.10mg of Si, and 0.02mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 2.00% Mn, 0.10% Si, 0.02% K, which is used as control point 2 in the standard curve.

Pipette 1.00mg of Mn, 0.05mg of Si, and 0.01mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 1.00% Mn, 0.05% Si, 0.01% K, which is used as control point 3 in the standard curve.

In the best state of the instrument, according to the selected instrument working conditions, standardize the blank solution and a series of standard solutions in turn to obtain a standard working curve, and use the least square method to fit the data to obtain the standard values of Mn, Si, and K elements. The curve data are shown in Table 2-Table 4.

Table 2 Standard working curve data of Mn element

Table 3 Standard working curve data of Si element

Table 4 Standard working curve data of K elements

(6) Method detection limit test

The detection limit is an important indicator of the analytical method and the instrument used for trace analysis, which indicates the lowest concentration of the element that can be detected by the method. According to the International Union of Theoretical and Applied Chemistry (IUPAC), the detection limit is defined as: "The detection limit is expressed in concentration (or mass), and refers to the lowest analytical signal XL that can be reasonably detected by a specific analytical method. Concentration CL (or mass gL)". In spectroscopic analysis, the detection limit refers to the minimum amount or concentration of the component required to produce an analytical signal confirming the presence of the analyte in the sample. Under the condition that the measurement error obeys a normal distribution, the detection limit refers to the minimum amount or minimum concentration of the component to be detected that can be detected by the method with a given confidence level (usually the confidence level is 99.7%). May be derived from the minimum detected signal and blank noise.

According to the recommendation of the International Organization for Standardization (ISO), when determining the detection limit of the analytical method, it is recommended to use a blank (reagent blank or blank solution containing matrix) and a sample close to the blank (that is, the concentration of the component to be tested is at the detection limit level). Nearby samples) are measured enough times, and Sb and b are calculated according to the measured data, and the detection limit of a certain component to be tested can be obtained by the analytical method according to the formula (2.1).

In the formula: - the average value of the analytical signal measured when the analytical sample is at the detection limit level;

- the average value of the blank signal measured for enough times (12 times in this experiment) to the blank sample;

S _b - the standard deviation of the measurement blank sample;

b—The slope of the calibration curve in the low concentration area, which indicates the change of the analytical signal when the component to be measured changes by one unit, that is, the sensitivity;

k—Constant related to confidence, IUPAC recommends k=3, 95%.

In this experiment, under certain conditions, according to the program set by the instrument, the zero point of the curve is used as the liquid to be tested to determine the detection limit according to the above method. The measurement results are shown in Table 5 below.

Table 5 Detection limits of analytes

(7), the analysis steps are as follows:

(7.1), sample: weigh 0.10g sample, accurate to 0.0001g;

(7.2) Preparation of sample solution: Place the sample weighed in 7.1 in a platinum crucible, remove the crucible lid, and place it on an electric furnace to slowly heat up for 12 hours. Remove the organic reagents such as hydrazine hydrate on the surface of the sample, take it off and cool it slightly, cover the crucible lid, put it into the muffle furnace and burn it at 1000°C for 2 hours, then take it out. Add 5mL of hydrochloric acid, 5 drops of hydrofluoric acid. After the solution is clear, transfer it to a 100mL plastic volumetric flask, dilute to the mark with water, and mix well. Simultaneously process blank samples.

(7.3), prepare working curve solution;

The curve solution prepared in the preparation work is adopted in step (5); the highest point of the curve solution must cover the analysis range of manganese, silicon and potassium in the sample;

(7.4), measure the concentration of manganese, silicon and potassium in the sample solution; According to the selected working conditions and analysis line of the inductively coupled plasma spectrometer, the standard curve is used to standardize the instrument, and then, measure manganese, silicon in the sample solution and potassium concentration, subtract the blank sample concentration, and calculate the percentage content ω obtained by the following formula, expressed in %;

In the formula: ρ _{is measured} as the mass concentration of manganese, silicon and potassium in graphene oxide, and the unit is mg/ml;

_{The measurement of} ρ is the mass concentration of manganese, silicon and potassium in the measured blank, and the unit is mg/ml;

V is the working curve solution volume, the unit is ml;

m is the mass of the sample to be weighed, in g.

Embodiment one

Graphene oxide prepared by the Hummers method is used as a sample to measure manganese, silicon and potassium content in graphene oxide, and an inductively coupled plasma spectrometer is used. The working conditions and analysis lines of the instrument are as follows: analysis lines: Mn 257.610nm, Si251.611nm, K 766.468nm;

2. Table 1 Instrument working conditions

project parameter project parameter High frequency, MHz 40.68 Incident power, kW 0.9 Entrance slit, μm 20 Sheath gas flow, L/min 0.2 Auxiliary air flow L/min 0.3 Sample lifting volume, mL/min 1.2 Integration time, s 2 Integral method one point Reflected power, W <10 - -

(1), the reagents used in the determination process are as follows:

(1.1), hydrochloric acid: ρ1.19g/mL, prepared by high-purity or sub-boiling distillation;

(1.2), nitric acid: ρ1.42g/mL, prepared by high-purity or sub-boiling distillation;

(1.3), hydrofluoric acid: ρ is about 1.15g/mL;

(1.4), sodium hydroxide: 100g/L.

(1.5), manganese standard solution A: 1.00mg/mL.

Weigh 0.5000g manganese metal (w(Mn)>99.99%), and place it in a 200mL beaker. Add 3mL of water and 3mL of nitric acid, heat to dissolve completely, and boil to drive away nitrogen oxides. Cool to room temperature, transfer to a 500ml volumetric flask, add 40mL nitric acid, and dilute with water to the mark.

(1.6), silicon standard solution A: 0.50mg/mL;

Weigh 5.06g of sodium silicate (Na2SiO3 9H2O), place it in a 250mL polytetrafluoroethylene beaker, and dissolve it in water. Add 4mL of sodium hydroxide solution, transfer to a plastic bottle, dilute to 800mL with water, place for 72h, filter in a 1000mL volumetric flask, dilute with water to the mark, mix well and immediately transfer to a dry plastic bottle. Its exact concentration is calibrated according to 4.9 in HB 5218.6-2004.

(1.7), silicon standard solution A: 0.10mg/mL;

Pipette 50.00mL of silicon standard solution A into a 250mL volumetric flask, add 20mL of hydrochloric acid, dilute to the mark with water, and mix well.

(1.8), potassium standard solution A: 1.00 mg/mL.

Accurately weigh 1.907g of potassium chloride (fired at 450°C to 500°C for 2h in advance), put it in a 300mL beaker, dissolve it in water, transfer it to a 1000mL volumetric flask, dilute to the mark with water, and shake well.

(1.9), potassium standard solution B: 0.10 mg/mL.

Pipette 25.00mL potassium standard solution A into a 250mL volumetric flask, dilute to the mark with water, and mix well.

(1.10), potassium standard solution C: 0.01mg/mL.

Pipette 25.00mL potassium standard solution B into a 250mL volumetric flask, dilute to the mark with water, and mix well.

(2) Sampling and sample preparation: The samples for analysis are sampled according to the systematic sampling method, that is, each bag of samples in a batch of products is arranged in a certain order, and a bag is randomly selected from the first bag to the nth bag of products Sampling is carried out, and then every n-γ bag is taken for sampling, and the sampling amount in each bag is the same. The samples taken are combined and mixed as samples of this batch of products, and the total sampling amount is not less than 5g.

(3), sample dissolution test

Graphene oxide is highly active, but common inorganic acids cannot digest it under normal temperature and pressure, so it is difficult to transform the sample into a liquid for analysis. Graphene oxide has a large specific surface area, and graphene adsorbs a large amount of hydrazine hydrate during the oxidation process. If the heating rate is too fast, it will cause a violent reaction, and the sample will splash and cause loss. After many experiments and explorations, it was determined that the electric furnace was heated at a low temperature step by step to remove organic reagents such as hydrazine hydrate; after that, it was fired at a high temperature of 1000°C in a muffle furnace to obtain the residual oxides that removed the carbon matrix; after burning, the oxides were finally treated with 5ml hydrochloric acid, 5 Drops of hydrofluoric acid are dissolved, and the dissolved sample after treatment is transparent and clear, which can meet the requirements of spectral analysis for sample solution.

(4) Interference test of coexisting elements

Prepare a single element test solution, scan in the 0.1842nm window range near the center wavelength of 2 to 4 analytical spectral lines of each analytical element, and obtain the spectral scanning pattern of a single interfering element solution, analytical element solution and reagent blank solution. The spectra were superimposed and enlarged to study the spectral interference. The final analysis line: Mn257.610nm, Si 251.611nm, K 766.468nm

(5) Working curve linearity test

Pipette 6.00mg of Mn, 0.30mg of Si, and 0.15mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 6.00% Mn, 0.30% Si, 0.15% K, which is the highest point in the standard curve.

Pipette 4.00mg of Mn, 0.20mg of Si, and 0.05mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 4.00% Mn, 0.20% Si, 0.05% K, which is used as control point 1 in the standard curve.

Pipette 2.00mg of Mn, 0.10mg of Si, and 0.02mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 2.00% Mn, 0.10% Si, 0.02% K, which is used as control point 2 in the standard curve.

Pipette 1.00mg of Mn, 0.05mg of Si, and 0.01mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 1.00% Mn, 0.05% Si, 0.01% K and is used as control point 3 in the standard curve.

Configured in the best state of the instrument, according to the selected working conditions of the instrument, standardize the blank solution and a series of standard solutions in turn to obtain a standard working curve, and use the least square method to fit the data to obtain the Mn, Si, K elements Standard Curve Data.

(6) Method detection limit test

The detection limit is an important indicator of the analytical method and the instrument used for trace analysis, which indicates the lowest concentration of the element that can be detected by the method. According to the International Union of Theoretical and Applied Chemistry (IUPAC), the detection limit is defined as: "The detection limit is expressed in concentration (or mass), and refers to the lowest analytical signal XL that can be reasonably detected by a specific analytical method. Concentration CL (or mass gL)". In spectroscopic analysis, the detection limit refers to the minimum amount or concentration of the component required to produce an analytical signal confirming the presence of the analyte in the sample. Under the condition that the measurement error obeys a normal distribution, the detection limit refers to the minimum amount or minimum concentration of the component to be detected that can be detected by the method with a given confidence level (usually the confidence level is 99.7%). May be derived from the minimum detected signal and blank noise.

According to the recommendation of the International Organization for Standardization (ISO), when determining the detection limit of the analytical method, it is recommended to use a blank (reagent blank or blank solution containing matrix) and a sample close to the blank (that is, the concentration of the component to be tested is at the detection limit level). Nearby samples) are measured enough times, and Sb and b are calculated according to the measured data, and the detection limit of a certain component to be tested can be obtained by the analytical method according to the formula (2.1).

In the formula: - the average value of the analytical signal measured when the analytical sample is at the detection limit level;

- the average value of the blank signal measured for enough times (12 times in this experiment) to the blank sample;

S _b - the standard deviation of the measurement blank sample;

b—The slope of the calibration curve in the low concentration area, which indicates the change of the analytical signal when the component to be measured changes by one unit, that is, the sensitivity;

k—Constant related to confidence, IUPAC recommends k=3, 95%.

In this experiment, under certain conditions, according to the program set by the instrument, the zero point of the curve is used as the liquid to be tested to determine the detection limit according to the above method.

Table 5 Detection limits of analytes

(7), the analysis steps are as follows:

(7.1), sample: weigh 0.1000g sample, accurate to 0.0001g;

(7.2) Preparation of sample solution: put the sample treated in 7.1 into a platinum crucible, remove the crucible cover, and place it on an electric furnace for 1 hour at 100°C, 2 hours at 200°C, 2 hours at 300°C, and 2 hours at 400°C Keep it for 2 hours, take it off to cool slightly, cover the crucible lid, and then burn it in a muffle furnace at a high temperature of 1050°C to obtain the residual oxides that remove the carbon matrix; after burning, the oxides are finally dissolved with 5ml hydrochloric acid and 5 drops of hydrofluoric acid , the dissolved sample after treatment is transparent and clear, which can meet the requirements of spectral analysis for sample solution. After the solution is clear, transfer it to a 100mL plastic volumetric flask, dilute to the mark with water, and mix well. Simultaneously process blank samples.

(7.3), prepare working curve solution;

Use (5) to prepare the solution in the working curve; the highest point of the curve solution must cover the analysis range of manganese, silicon and potassium in the sample;

(7.4), measure the concentration of manganese, silicon and potassium in the sample solution; According to the selected working conditions and analysis line of the inductively coupled plasma spectrometer, the standard curve is used to standardize the instrument, and then, measure manganese, silicon in the sample solution and potassium concentration, subtract the blank sample concentration, and calculate the percentage content ω obtained by the following formula, expressed in %;

In the formula: ρ _{is measured} as the mass concentration of manganese, silicon and potassium in graphene oxide, and the unit is mg/ml;

_{The measurement of} ρ is the mass concentration of manganese, silicon and potassium in the measured blank, and the unit is mg/ml;

V is the working curve solution volume, the unit is ml;

m is the mass of the sample to be weighed, in g.

The obtained manganese content is 5.25%, the silicon content is 0.15%, and the potassium content is 0.05%;

Embodiment two

Graphene oxide prepared by the Hummers method was used as a sample to measure the contents of manganese, silicon and potassium in the graphene oxide. The working conditions of the instrument and the analysis line were as in Example 1.

(1), the reagent used in the assay process is consistent with Example 1;

(2), sampling and sample preparation are consistent with embodiment 1;

(3), sample dissolution test is consistent with embodiment 1;

(4), coexistence element interference test is consistent with embodiment 1;

(5), working curve linearity test

Pipette 8.00mg of Mn, 0.50mg of Si, and 0.20mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 8.00% Mn, 0.50% Si, 0.20% K, which is the highest point in the standard curve.

Pipette 6.00mg of Mn, 0.30mg of Si, and 0.10mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 6.00% Mn, 0.30% Si, 0.10% K, which is used as control point 1 in the standard curve.

Pipette 4.00mg of Mn, 0.20mg of Si, and 0.05mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 4.00% Mn, 0.20% Si, 0.05% K, which is used as control point 2 in the standard curve.

Pipette 2.00mg of Mn, 0.10mg of Si, and 0.02mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 2.00% Mn, 0.10% Si, 0.02% K and is used as control point 3 in the standard curve.

Configured in the best state of the instrument, according to the selected working conditions of the instrument, standardize the blank solution and a series of standard solutions in turn to obtain a standard working curve, and use the least square method to fit the data to obtain the Mn, Si, K elements Standard Curve Data.

(6), method detection limit test is consistent with embodiment 1;

(7), the analysis steps are as follows:

(7.1), sample: weigh 0.2000g sample;

(7.2) Preparation of sample solution: put the sample treated in 7.1 into a platinum crucible, remove the crucible cover, and place it on an electric furnace at 100°C for 1.5 hours, at 200°C for 2 hours, at 300°C for 2 hours, at 400°C Keep it for 2 hours, take it off to cool slightly, cover the crucible lid, and then burn it in a muffle furnace at a high temperature of 1000°C to obtain the residual oxide that removes the carbon matrix; after burning, the oxide is finally dissolved with 5ml hydrochloric acid and 5 drops of hydrofluoric acid , the dissolved sample after treatment is transparent and clear, which can meet the requirements of spectral analysis for sample solution. After the solution is clear, transfer it to a 100mL plastic volumetric flask, dilute to the mark with water, and mix well. Simultaneously process blank samples.

(7.3), prepare working curve solution;

Use (5) to prepare the solution in the working curve; the highest point of the curve solution must cover the analysis range of manganese, silicon and potassium in the sample;

(7.4), measure the concentration of manganese, silicon and potassium in the sample solution; According to the selected working conditions and analysis line of the inductively coupled plasma spectrometer, the standard curve is used to standardize the instrument, and then, measure manganese, silicon in the sample solution and potassium concentration, subtract the blank sample concentration, and calculate the percentage content ω obtained by the following formula, expressed in %;

In the formula: ρ _{is measured} as the mass concentration of manganese, silicon and potassium in graphene oxide, and the unit is mg/ml;

_{The measurement of} ρ is the mass concentration of manganese, silicon and potassium in the measured blank, and the unit is mg/ml;

V is the working curve solution volume, the unit is ml;

m is the mass of the sample to be weighed, in g.

The resulting manganese content was 5.22%, silicon content was 0.16%, and potassium content was 0.06%;

Embodiment three

Graphene oxide prepared by the Hummers method was used as a sample to measure the contents of manganese, silicon and potassium in the graphene oxide. The working conditions of the instrument and the analysis line were as in Example 1.

(1), the reagent used in the assay process is consistent with Example 1;

(2), sampling and sample preparation are consistent with embodiment 1;

(3), sample dissolution test is consistent with embodiment 1;

(4), coexistence element interference test is consistent with embodiment 1;

(5), working curve linearity test

Pipette 8.00mg of Mn, 0.50mg of Si, and 0.20mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 8.00% Mn, 0.50% Si, 0.20% K, which is the highest point in the standard curve.

Pipette 6.00mg of Mn, 0.30mg of Si, and 0.10mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 6.00% Mn, 0.30% Si, 0.10% K, which is used as control point 1 in the standard curve.

Pipette 4.00mg of Mn, 0.20mg of Si, and 0.05mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 4.00% Mn, 0.20% Si, 0.05% K, which is used as control point 2 in the standard curve.

Pipette 2.00mg of Mn, 0.10mg of Si, and 0.02mg of K into a 100mL volumetric flask, add 10mL of hydrochloric acid and 5 drops of hydrofluoric acid, dilute to the mark with water, and shake well. This mixed standard solution contains 2.00% Mn, 0.10% Si, 0.02% K and is used as control point 3 in the standard curve.

Configured in the best state of the instrument, according to the selected working conditions of the instrument, standardize the blank solution and a series of standard solutions in turn to obtain a standard working curve, and use the least square method to fit the data to obtain the Mn, Si, K elements Standard Curve Data.

(6), method detection limit test is consistent with embodiment 1;

(7), the analysis steps are as follows:

(7.1), sample: weigh 0.1000g sample;

(7.2) Preparation of sample solution: put the sample treated in 7.1 into a platinum crucible, remove the crucible cover, and place it on an electric furnace for 2 hours at 100°C, 2 hours at 200°C, 2 hours at 300°C, and 2 hours at 400°C Keep it for 2 hours, take it off to cool slightly, cover the crucible lid, and then burn it in a muffle furnace at a high temperature of 980°C to obtain the residual oxide that removes the carbon matrix; after burning the oxide is finally treated with 5ml hydrochloric acid (1.1), 5 drops of hydrogen Hydrofluoric acid (1.3) dissolves, and the dissolved sample after treatment is transparent and clear, which can meet the requirements of spectral analysis for sample solution. After the solution is clear, transfer it to a 100 mL plastic volumetric flask, dilute to the mark with water, and mix well. Simultaneously process blank samples.

(7.3), prepare working curve solution;

Use (5) to prepare the solution in the working curve; the highest point of the curve solution must cover the analysis range of manganese, silicon and potassium in the sample;

(7.4), measure the concentration of manganese, silicon and potassium in the sample solution; According to the selected working conditions and analysis line of the inductively coupled plasma spectrometer, the standard curve is used to standardize the instrument, and then, measure manganese, silicon in the sample solution and potassium concentration, subtract the blank sample concentration, and calculate the percentage content ω obtained by the following formula, expressed in %;

In the formula: ρ _{is measured} as the mass concentration of manganese, silicon and potassium in graphene oxide, and the unit is mg/ml;

_{The measurement of} ρ is the mass concentration of manganese, silicon and potassium in the measured blank, and the unit is mg/ml;

V is the working curve solution volume, the unit is ml;

m is the mass of the sample to be weighed, in g.

The resulting manganese content was 5.25%, the silicon content was 0.14%, and the potassium content was 0.05%.

Claims (6)

1. An analytical method for measuring manganese, silicon and potassium in graphene oxide is characterized in that: a platinum crucible is used as a container, and graphene oxide is heated up to 400° C. in steps in an electric furnace, and then a muffle furnace is used at 1000 ± 50 Burn at ℃ to obtain the residual oxides that remove the carbon matrix; after burning, the oxides are dissolved in a 20:1 mixed solution of hydrochloric acid and hydrofluoric acid, and the dissolved samples after treatment are transparent and clear. Mn 257.610nm, Si251.611nm, and K 766.468nm are used as analysis lines, and the measurement is carried out under the working condition of the instrument's high-frequency incident power of 0.9kW. 2. The analytical method for measuring manganese, silicon and potassium in graphene oxide as claimed in claim 1, characterized in that: the weighing quality of the graphene oxide sample can be 0.1000g to 0.5000g according to the content of the element to be measured. 3. The analytical method for measuring manganese, silicon and potassium in graphene oxide as claimed in claim 2, characterized in that: the stepwise temperature rise of the electric furnace is 100 ± 10°C for 1 hour, 200 ± 10°C for 2 hours, 300±10°C for 2 hours, 400±10°C for 2 hours. 4. The analytical method for measuring manganese, silicon and potassium in graphene oxide as claimed in claim 3, characterized in that: the muffle furnace is burned at 1000±50° C. for at least 1 hour, depending on the oxidation of the sample, it can be appropriately increased. to 2 hours. 5. the analytical method of manganese, silicon and potassium in the mensuration graphene oxide as described in any one of claim 1-4, it is characterized in that: the mixed solution of described hydrochloric acid, hydrofluoric acid is 5mL hydrochloric acid, 5 drops of hydrofluoric acid acid. 6. the analytical method of manganese, silicon and potassium in the mensuration graphene oxide as claimed in claim 5 is characterized in that: the manganese element detection range of described graphene oxide sample is 0.10%～10.0%, the silicon element detection range is 0.05% ~1.00%, the detection range of potassium is 0.01%~0.20%.