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GB/T 20975.25-2020: Methods for chemical analysis of aluminium and aluminium alloys - Part 25: Determination of elements content--Inductively coupled plasma atomic emission spectrometric method
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Methods for chemical analysis of aluminium and aluminium alloys - Part 25: Determination of elements content--Inductively coupled plasma atomic emission spectrometric method
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GB/T 20975.25-2020
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| GB/T 20975.25-2008 | English | 439 |
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Methods for chemical analysis of aluminium and aluminium alloys -- Part 25: Inductively coupled plasma atomic emission spectrometric method
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Basic data | Standard ID | GB/T 20975.25-2020 (GB/T20975.25-2020) | | Description (Translated English) | Methods for chemical analysis of aluminium and aluminium alloys - Part 25: Determination of elements content--Inductively coupled plasma atomic emission spectrometric method | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | H12 | | Classification of International Standard | 77.120.10 | | Word Count Estimation | 14,144 | | Date of Issue | 2020-06-02 | | Date of Implementation | 2021-04-01 | | Older Standard (superseded by this standard) | GB/T 20975.25-2008 | | Quoted Standard | GB/T 8005.2; GB/T 8170-2008 | | Issuing agency(ies) | State Administration for Market Regulation, China National Standardization Administration | | Summary | This standard specifies the determination of silicon, iron, copper, gallium, magnesium, manganese, chromium, nickel, zinc, titanium, silver, boron, bismuth, lithium, lead, tin, Vanadium, zirconium, barium, beryllium, calcium, cadmium, cobalt, bait, hafnium, indium, potassium, sodium, molybdenum, neodymium, phosphorus, antimony, scandium, silver, tungsten, yttrium, ytterbium content. This standard applies to silicon, iron, copper, gallium, magnesium, manganese, chromium, nickel, zinc, titanium, silver, boron, bismuth, lithium, lead, tin, vanadium, zirconium, barium, beryllium, calcium in aluminum and aluminum alloys , cadmium, cobalt, bait, hafnium, indium, potassium, sodium, molybdenum, neodymium, phosphorus, antimony, scandium, silver, tungsten, yttrium, ytterbium content determination, the determination range is shown in Table 1. | GB/T 20975.25-2020: Methods for chemical analysis of aluminium and aluminium alloys - Part 25: Determination of elements content--Inductively coupled plasma atomic emission spectrometric method
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Methods for chemical analysis of aluminium and aluminium alloys--Part 25.Determination of elements content--Inductively coupled plasma atomic emission spectrometric method
ICS 77.120.10
H12
National Standards of People's Republic of China
Replace GB/T 20975.25-2008
Chemical analysis methods of aluminum and aluminum alloys
Part 25.Determination of element content
Inductively coupled plasma atomic emission spectrometry
2020-06-02 released
Implementation on 2021-04-01
State Administration for Market Regulation
Issued by the National Standardization Management Committee
Foreword
GB/T 20975 "Methods for Chemical Analysis of Aluminum and Aluminum Alloys" is divided into 37 parts.
---Part 1.Determination of mercury content;
---Part 2.Determination of arsenic content;
---Part 3.Determination of copper content;
---Part 4.Determination of iron content;
---Part 5.Determination of silicon content;
---Part 6.Determination of cadmium content;
---Part 7.Determination of manganese content;
---Part 8.Determination of zinc content;
---Part 9.Determination of lithium content by flame atomic absorption spectrometry;
---Part 10.Determination of tin content;
---Part 11.Determination of lead content;
---Part 12.Determination of titanium content;
---Part 13.Determination of vanadium content;
---Part 14.Determination of nickel content;
---Part 15.Determination of boron content;
---Part 16.Determination of magnesium content;
---Part 17.Determination of strontium content;
---Part 18.Determination of chromium content;
---Part 19.Determination of Zirconium Content;
---Part 20.Determination of Gallium Content Butyl Rhodamine B Spectrophotometry;
---Part 21.Determination of calcium content;
---Part 22.Determination of beryllium content;
---Part 23.Determination of antimony content;
---Part 24.Determination of total rare earth content;
---Part 25.Determination of element content by inductively coupled plasma atomic emission spectrometry;
---Part 26.Determination of carbon content by infrared absorption method;
---Part 27.Determination of cerium, lanthanum and scandium content by inductively coupled plasma atomic emission spectrometry;
---Part 28.Determination of cobalt content by flame atomic absorption spectrometry;
---Part 29.Determination of molybdenum content thiocyanate spectrophotometric method;
---Part 30.Determination of hydrogen content by heating extraction thermal conductivity method;
---Part 31.Determination of phosphorus content molybdenum blue spectrophotometric method;
---Part 32.Determination of Bismuth Content;
---Part 33.Determination of potassium content by flame atomic absorption spectrometry;
---Part 34.Determination of sodium content by flame atomic absorption spectrometry;
---Part 35.Determination of Tungsten Content Thiocyanate Spectrophotometric Method;
---Part 36.Determination of silver content by flame atomic absorption spectrometry;
--- Part 37.Determination of Niobium Content.
This part is part 25 of GB/T 20975.
This section was drafted in accordance with the rules given in GB/T 1.1-2009.
This part replaces GB/T 20975.25-2008 "Methods for chemical analysis of aluminum and aluminum alloys Part 25.Inductively coupled plasma
Sub-Emission Spectroscopy. Compared with GB/T 20975.25-2008, the main technical changes except for editorial changes are as follows.
--- Added standard use safety warnings;
---Added 15 elements such as Ag, Ba, Co, W, Mo, Er, K, Na, Li, Nd, Y, Yb, Hf, P, Sc (see Chapter 1);
---Modified the determination range of 18 elements such as Fe, Cu, Mn, Ti, V, Sn, Zn, Zr, Ca, Bi, Cr, Ni, Cd, Be, B, Si, Sr, Sb, etc.
Wai (see Chapter 1, Chapter 1 of the.2008 edition);
--- Added "Normative Reference Documents" (see Chapter 2);
--- Added "Terms and Definitions" (see Chapter 3);
---Added the requirements for reagents and water used in analysis (see Chapter 5);
--- Deleted "Quality Assurance and Control" (see Chapter 9 of the.2008 edition).
--- Added "Test Report" (see Chapter 11).
This part was proposed by China Nonferrous Metals Industry Association.
This part is under the jurisdiction of the National Nonferrous Metals Standardization Technical Committee (SAC/TC243).
Drafting organizations of this section. Chinalco Zhengzhou Nonferrous Metal Research Institute Co., Ltd., Nonferrous Metal Technology and Economic Research Institute, Guizhou Province Analysis and Testing
Research Institute, Beijing Research Institute of Nonferrous Metals and Rare Earth Application, Northeast Light Alloy Co., Ltd., Changsha Research Institute of Mining and Metallurgy Co., Ltd., He
Beisitong New Metal Materials Co., Ltd., Shandongnanshan Aluminum Co., Ltd., Kunming Metallurgical Research Institute, Henan Terun Technology Services
Co., Ltd., Youyan Yijin New Materials Co., Ltd., Chinalco Luoyang Copper Processing Co., Ltd., China Aluminum Materials Application Research Institute Co., Ltd., Guangxi Liu
Zhou Yinhai Aluminum Co., Ltd., Shandong Yankuang Light Alloy Co., Ltd., Southwest Aluminum (Group) Co., Ltd., Inner Mongolia Huomei Hongjun
Aluminum Electricity Co., Ltd.
The main drafters of this section. Xue Ning, Shi Lei, Wu Yuqiang, Zhang Yingying, Zhang Shuchao, Xi Huan, Li Jiahua, Han Peng, Zhou Bing, Cui Hao, Li Wei,
Li Yanzhen, Wang Jinrong, Liu Chaofang, Li Shaowen, Zhang Huilin, Luo Fen, Wei Yanqin, Tan Jiaying, Bao Fangfang, Liu Meiling.
The previous versions of the standards replaced by this part are as follows.
---GB/T 20975.25-2008.
Chemical analysis methods of aluminum and aluminum alloys
Part 25.Determination of element content
Inductively coupled plasma atomic emission spectrometry
Warning---The personnel using this section should have formal laboratory work experience. This section does not indicate all possible safety
problem. The user is responsible for taking appropriate safety and health measures and ensuring compliance with the conditions stipulated by relevant national laws and regulations.
1 Scope
This part of GB/T 20975 specifies the inductively coupled plasma atomic emission spectrometry for the determination of silicon, iron, copper, gallium, and gallium in aluminum and aluminum alloys.
Magnesium, manganese, chromium, nickel, zinc, titanium, silver, boron, bismuth, lithium, lead, tin, vanadium, zirconium, barium, beryllium, calcium, cadmium, cobalt, bait, hafnium, indium, potassium, sodium, molybdenum, Neodymium, phosphorus, antimony, scandium,
Strontium, tungsten, yttrium, ytterbium content.
This part applies to silicon, iron, copper, gallium, magnesium, manganese, chromium, nickel, zinc, titanium, silver, boron, bismuth, lithium, lead, tin, vanadium, zirconium, barium, beryllium, aluminum and aluminum alloys.
Calcium, cadmium, cobalt, bait, hafnium, indium, potassium, sodium, molybdenum, neodymium, phosphorus, antimony, scandium, strontium, tungsten, yttrium, ytterbium content determination, the measurement range is shown in Table 1.
Table 1
2 Normative references
The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this article
Pieces. For undated references, the latest version (including all amendments) applies to this document.
GB/T 8005.2 Terminology of Aluminum and Aluminum Alloy Part 2.Chemical Analysis
GB/T 8170-2008 Numerical rounding rules and the expression and determination of limit values
3 Terms and definitions
The terms and definitions defined in GB/T 8005.2 apply to this document.
4 Method summary
According to the type of alloy and the content of elements, the following methods are used to dissolve the sample.
---Decompose the sample with hydrochloric acid and hydrogen peroxide;
---The mixed acid of hydrochloric acid and nitric acid decomposes the sample;
--- Sodium hydroxide solution and hydrogen peroxide decomposition sample;
---The mixed acid of hydrochloric acid and nitric acid, hydrofluoric acid decomposes the sample.
After the sample is decomposed, it is measured by inductively coupled plasma atomic emission spectrometer, and the influence of the matrix on the measurement is corrected by the matrix matching method.
5 Reagents
Unless otherwise stated, only reagents and laboratory secondary water confirmed to be analytically pure are used in the analysis.
5.1 Pure aluminum (wAl≥99.999%).
5.2 Hydrogen peroxide (ρ=1.10g/mL).
5.3 Hydrochloric acid (ρ=1.19g/mL), excellent grade pure.
5.4 Nitric acid (ρ=1.42g/mL), excellent grade pure.
5.5 Hydrofluoric acid (ρ=1.14g/mL), excellent grade pure.
5.6 Perchloric acid (ρ=1.76g/mL), excellent grade pure.
5.7 Hydrochloric acid (1 1).
5.8 Nitric acid (1 1).
5.9 Mixed acid. 3 parts of hydrochloric acid (5.7) and 1 part of nitric acid (5.8) are mixed.
5.10 Sodium hydroxide solution (400g/L).
5.11 Aluminum matrix solution (20mg/mL). Weigh 20.00g pure aluminum (5.1) into a 1000mL beaker, cover with a watch glass, and add in portions
The total amount is 600 mL of hydrochloric acid (5.7). After the violent reaction stops, slowly heat to complete dissolution, then add a few drops of hydrogen peroxide (5.2), and boil
Boil for a few minutes, cool, transfer the solution into a 1000mL volumetric flask, dilute to the mark with water, and shake well.
5.12 Standard storage solution of each analysis element. use the certified national standard solution to prepare; or refer to Appendix A.
5.13 Standard solution.
a) Principles for preparing multi-element standard solutions. Elements that have chemical interference, precipitation, and mutual spectral interference should be prepared in groups.
b) Dilute the standard storage solution (5.12) to 100μg/mL and maintain the same acidity as the standard storage solution (dilute when used).
c) Dilute the standard stock solution (5.12) to 10μg/mL and maintain the same acidity as the standard stock solution (dilute when used).
6 Instruments
Inductively coupled plasma atomic emission spectrometer. The instrument should meet the following conditions.
---The spectroscopic chamber has functions such as vacuuming or purging to ensure the stability of the element test signal at the test wavelength below.200nm.
---The resolution of the instrument is less than 0.005nm (at.200nm).
7 Sample
Process the sample into chips with a thickness of not more than 1mm.
8 Analysis steps
8.1 Sample
According to the sample dissolution method taken, weigh the corresponding mass (m0) sample (Chapter 7) according to Table 2 or Table 3, accurate to 0.0001g.
8.2 Parallel test
Do two tests in parallel and take the average value.
8.3 Blank test
Weigh the same amount of pure aluminum (5.1) as the sample, and do a blank test with the sample.
8.4 Preparation of analysis test solution
8.4.1 Sample dissolution method I
8.4.1.1 This sample solution method is suitable for aluminum and aluminum alloys such as iron, copper, magnesium, manganese, gallium, titanium, vanadium, indium, tin, chromium, zinc, nickel, cadmium, beryllium, strontium, calcium, barium,
Determination of potassium, sodium, cobalt, tungsten, molybdenum, bait, lithium, phosphorus, neodymium, yttrium, ytterbium, scandium content.
8.4.1.2 Place the sample (8.1) weighed according to Table 2 in a 250mL beaker, add 25mL of hydrochloric acid (5.7), and after the violent reaction stops
Warm heating to decompose the sample, add an appropriate amount of hydrogen peroxide (5.2), until the sample is completely dissolved, and cool to room temperature. Move into the corresponding volume of Table 2
Dilute to the mark with water in the measuring flask and mix well. If necessary, dilute the solution to be tested according to the working curve range.
8.4.1.3 When the silicon content is greater than 0.5%, if there is an insoluble residue, filter the test solution in a volumetric flask of the corresponding volume in Table 2, and wash the residue.
Place the residue together with the filter paper in a platinum crucible, ash (do not burn the filter paper), then burn it at 800°C for 5 minutes and cool. Add 5mL hydrofluoride
Acid (5.5), and add nitric acid (5.8) dropwise until the solution is clear, add 1mL perchloric acid (5.6), heat and evaporate to dryness, cool, and use 5mL hydrochloric acid
(5.7) Dissolve the residue, combine this test solution in the original filtrate, dilute to the mark, and mix. If necessary, dilute to be tested according to the working curve range
Solution.
8.4.2 Sample dissolution method Ⅱ
8.4.2.1 This sample solution method is suitable for iron, copper, magnesium, manganese, gallium, titanium, vanadium, indium, tin, lead, bismuth, antimony, chromium, zinc, nickel, cadmium, beryllium, aluminum and aluminum alloys.
Determination of boron, strontium, calcium, silver, barium, cobalt, lithium, molybdenum, neodymium, yttrium, ytterbium, and scandium content.
8.4.2.2 Place the sample (8.1) weighed according to Table 2 in a 250mL beaker, add 25mL of mixed acid (5.9), and wait for the violent reaction to stop,
Decompose by heating at low temperature until the sample is completely dissolved, then cool to room temperature.
8.4.2.3 When the mass fraction of silicon is greater than 0.5%, if there is insoluble residue, filter the test solution in a volumetric flask of the corresponding volume in Table 2, and wash the residue.
Scum. Place the residue together with the filter paper in a platinum crucible, ash (do not burn the filter paper), then burn it at 800°C for 5 minutes and cool. Join
5mL hydrofluoric acid (5.5), and add nitric acid (5.8) dropwise until the solution is clear, add 1mL perchloric acid (5.6), heat and evaporate to dryness, cool, use
5mL hydrochloric acid (5.7) to dissolve the residue, combine this test solution in the original filtrate, dilute to the mark, and mix. If necessary, according to the working curve range,
Release the solution to be tested.
8.4.3 Sample dissolution method Ⅲ
8.4.3.1 This method is suitable for silicon, iron, copper, magnesium, manganese, titanium, boron, vanadium, chromium, zinc, nickel, zirconium, strontium, tin, antimony, lead, calcium, aluminum and aluminum alloy.
Determination of tungsten, ytterbium, erbium, neodymium and scandium elements.
8.4.3.2 Place the sample (8.1) weighed according to Table 3 in a 400mL polytetrafluoroethylene beaker, add a little water, and add 6mL sodium hydroxide
Solution (5.10), after the violent reaction stops, heat it to decompose at low temperature, add an appropriate amount of hydrogen peroxide (5.2), and slowly heat until the sample is completely dissolved.
Steam the solution to a slurry, cool slightly, add about 30mL of water, and slowly heat until completely dissolved.
8.4.3.3 Dilute the solution (8.4.3.1) to about 100mL with water, add 25mL nitric acid (5.8) and 25mL hydrochloric acid (5.7) while stirring,
Heat at low temperature to completely dissolve it (if there is brown manganese dioxide precipitation, add anhydrous sodium sulfite solution), cool, and transfer the solution to 250mL
In a volumetric flask, dilute to the mark with water and mix well. If necessary, dilute the solution to be tested according to the working curve range.
8.4.4 Sample dissolution method IV
8.4.4.1 This method is suitable for zirconium, hafnium, iron, copper, magnesium, manganese, titanium, vanadium, chromium, zinc, nickel, aluminum and aluminum alloys with silicon content less than 0.50%.
Determination of strontium, tin and lead elements.
8.4.4.2 Place the sample (8.1) weighed according to Table 2 in a 100mL polytetrafluoroethylene beaker, add 25mL of mixed acid (5.9), and wait vigorously.
After the reaction has stopped, add an appropriate amount of hydrofluoric acid (5.5), heat at low temperature to dissolve completely, cool to room temperature, and transfer to a volumetric flask of the corresponding volume in Table 2.
Dilute to the mark with water and mix well. If necessary, dilute the solution to be tested according to the working curve range.
8.4.4.3 When measuring elements that are easily hydrolyzed, such as Ti, Sn, Zr, Sb, the test solution should maintain 10% acidity; if measuring low-content elements that are easily contaminated
When, such as Ca, Pb, B, high purity acid and quartz sub-boiling distilled water should be used.
8.5 Preparation of standard solutions
8.5.1 When using sample dissolution methods I, II, and IV, according to the aluminum content in the test solution, pipette an appropriate amount of aluminum matrix solution (5.11) into a set of 100 mL volumes
In the measuring flask, make the amount of aluminum in the standard solution basically the same as the amount of aluminum in the test solution, and add an appropriate amount of the standard storage solution of the element to be tested (5.12)
Or standard solution (5.13), so that the acidity of the standard curve solution is basically the same as that of the test solution, dilute to the mark with water, and mix. Not to
The test solution with standard solution is used as the blank solution, the content of the element to be tested should be within the range of the working curve, the number of the series standard curve solution
Determined by accuracy requirements, generally 3~5.
8.5.2 When using sample dissolution method III, weigh an appropriate amount of pure aluminum (5.1) into a series of PTFE beakers according to the aluminum content in the sample, and cover with the table
For the face dish, the following operations should be carried out according to step 8.4.3, before being diluted to the scale, add an appropriate amount of standard stock solution (5.12) or standard
Solution (5.13), make the acidity of the standard curve solution basically the same as the acidity of the test solution, dilute to the mark with water, and mix. Without standard
The test solution of the solution is used as a blank solution. The content of the element to be tested should be within the range of the working curve. The quantity of the series standard curve solution is determined by the accuracy
Request to decide, usually 3~5.
8.5.3 According to the sample brand number, you can also choose the corresponding standard sample (national first-level standard sample), and prepare the series according to the preparation method of the analysis test solution (8.4)
The number of standard solutions and series of standard curve solutions is determined by the accuracy requirements, generally 3~5.
8.6 Determination
Select the appropriate analysis conditions of the instrument and the analysis spectrum of each element (see Appendix B), and introduce the series of standard curve solutions (8.5) into the electric
In the inductively coupled plasma atomic emission spectrometer, the intensity of each element in a series of standard solutions is measured at the selected wavelength of each element. Work
When the linear correlation coefficient of the curve is ≥0.9995, the analysis solution (8.4) can be determined.
9 Test data processing
The content of each element to be tested is calculated as the mass fraction wx of each element to be tested and calculated according to formula (1). It can also be automatically given by the computer.
10 Precision
10.1 Repeatability
The measured values of two independent test results obtained under repeatability conditions, within the average range given below, these two test results
The absolute difference does not exceed the repeatability limit r, and the repeatability limit r does not exceed 5%. The repeatability limit r is within the linear range according to the data in Table 4.
Obtained by interpolation or extension method.
10.2 Reproducibility
The measured values of two independent test results obtained under reproducibility conditions, within the average range given below, these two test results
The absolute difference of is not greater than the reproducibility limit R, and the case of exceeding the reproducibility limit R does not exceed 5%. Reproducibility limit R is linear according to the data in Table 5
Obtained by interpolation or extension.
11 Test report
The test report should include the following.
a) Number and name of this part;
b) All necessary information about identification of samples, laboratory, analysis date, report date, etc.;
c) Express the test results in an appropriate form;
d) Abnormal phenomena during the test;
e) Signatures of review and approval personnel.
Appendix A
(Informative appendix)
Preparation of standard stock solutions
A.1 Silicon standard stock solution (0.5mg/mL).
Weigh 1.0697g of silicon dioxide (spectrally pure) previously burnt to constant weight at 1000°C in a platinum crucible, cover with a platinum watch glass, and add
5g mixture of sodium carbonate and potassium carbonate (11), melt until transparent, and cool. Dissolve the frit with warm water, transfer it into a polyethylene cup, and dilute with water
To 700mL, transfer to a 1000mL volumetric flask, dilute to the mark with water, and mix. 1mL of this solution contains 0.5mg of silicon (stored in polyethylene
Olefin bottle).
A.2 Iron standard stock solution (1mg/mL).
Weigh 1.0000g iron (wFe≥99.99%) into a 400mL beaker, cover with a watch glass, add 40mL hydrochloric acid (5.7), slowly add
Heat to completely dissolve, cool, transfer the solution into a 1000mL volumetric flask, dilute to the mark with water, and mix. This solution 1mL contains
1mg iron.
A.3 Copper standard stock solution (1mg/mL).
Weigh 1.0000g copper (wCu≥99.99%) into a 400mL beaker, cover with a watch glass, add 20mL nitric acid (5.8), slowly add
Heat to completely dissolve, cool, transfer the solution into a 1000mL volumetric flask, dilute to the mark with water, and mix. This solution 1mL contains
1mg copper.
A.4 Manganese standard stock solution (1mg/mL).
Weigh 1.0000g manganese (wMn≥99.99%) into a 400mL beaker, cover with a watch glass, add 40mL hydrochloric acid (5.7), slowly
Heat to complete dissolution, cool, transfer the solution to a 1000mL volumetric flask, dilute to the mark with water, and mix. This solution 1mL contains
1mg manganese.
A.5 Magnesium standard stock solution (1mg/mL).
Weigh 1.0000g magnesium (wMg≥99.99%) into a 400mL beaker, cover with a watch glass, add 40mL hydrochloric acid (5.7), slowly
Heat to complete dissolution, cool, transfer the solution to a 1000mL volumetric flask, dilute to the mark with water, and mix. This solution 1mL contains
1mg magnesium.
A.6 Nickel standard stock solution (1mg/mL).
Weigh 1.0000g nickel (wNi≥99.99%) into a 400mL beaker, cover with a watch glass, add 40mL hydrochloric acid (5.7), slowly add
Heat to completely dissolve, cool, transfer the solution into a 1000mL volumetric flask, dilute to the mark with water, and mix. This solution 1mL contains
1mg nickel.
A.7 Zinc standard stock solution (1mg/mL).
Weigh 1.0000g zinc (wZn≥99.99%) into a 400mL beaker, cover with a watch glass, add 40mL hydrochloric acid (5.7), slowly add
Heat to completely dissolve, cool, transfer the solution into a 1000mL volumetric flask, dilute to the mark with water, and mix. This solution 1mL contains
1mg zinc.
A.8 Beryllium standard stock solution (1mg/mL).
Weigh 1.0000g beryllium (wBe≥99.99%) into a 400mL beaker, cover with a watch glass, add 40mL hydrochloric acid (5.7), and slowly add
Heat to completely dissolve, cool, transfer the solution into a 1000mL volumetric flask, dilute to the mark with water, and mix. This solution 1mL contains
1mg beryllium.
A.9 Chromium standard stock solution (1mg/mL).
Weigh 2.8285g potassium dichromate (reference reagent) dried at 140°C in a 400mL beaker, cover with a watch glass, and add
Dissolve in 20 mL of water and 20 mL of hydrochloric acid (5.7). Add 20mL hydrogen peroxide (5.2) dropwise, leave it for 12h~24h until the yellow color of the solution disappears completely
Lose, slowly heat (do not boil) to decompose the excess hydrogen peroxide, cool, transfer the solution into a 1000mL volumetric flask, dilute with water to
Degree, mix well. This solution 1mL contains 1mg chromium.
A.10 Titanium standard stock solution (1mg/mL).
Weigh 1.0000g titanium (wTi≥99.99%) in a platinum crucible, add a little water, slowly add hydrofluoric acid (5.5) dropwise to dissolve the sample, and then
Add nitric acid (5.8) dropwise to completely oxidize the low-valent titanium, add 10mL sulfuric acid (1 1), shake well, heat and evaporate until sulfuric acid white smoke is just emitted, remove and cool
After that, the solution was transferred to a 1000mL volumetric flask, diluted to the mark with sulfuric acid (595), and mixed. 1mL of this solution contains 1mg of titanium.
A.11 Gallium standard stock solution (1mg/mL).
Weigh 1.0000g gallium (wGa≥99.99%) into a 400mL beaker, cover with a watch glass, add 40mL hydrochloric acid (5.7), add a few drops
Drop nitric acid (5.8), slowly heat until completely dissolved, cool, tran...
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