GB/T 8647.5-1988 Chemical analysis of nickel - Determination of magnesium content by flame atomic absorption spectrophotometry GB/T8647.5-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Nickel Chemical Analysis Method
Flame Atomic Absorption Spectrophotometric Method for Determination of Magnesium Content Nickel -- Determination of Magnesium Content Flame atomic absorption spectrophotametric method This standard is applicable to the determination of magnesium content in nickel. Determination range: 0.0005%~0.0020%. UDC 669. 24
GB8647.5-88
This standard complies with (B1467--78 "General Principles and General Provisions of Chemical Analysis Methods for Metallurgical Products". 1 Method Summary
The sample is decomposed with nitric acid. In a dilute nitric acid medium, an air-acetylene flame is used to measure the absorbance of magnesium at a wavelength of 285.3nm using an atomic absorption spectrophotometer.
The standard solution should contain the same concentration of nickel matrix as the sample solution. 2 Reagents
The water used for preparing solutions and analysis is double distilled water. 2.1 Metallic nickel (containing 0.0001% magnesium).
2.2 Nitric acid (1+1), high-grade pure.
2.3 Nitric acid (1+19), high-grade pure.
Note: The same batch of nitric acid should be used for the entire experimental process. 2.4 Magnesium standard storage solution: Weigh 0.1658g of high-grade pure magnesium oxide that has been calcined at 900℃ for 0.5h, place it in a 250mL beaker, carefully add 20mL nitric acid (2.2), cover with Table III, completely dissolve, slightly boil to drive off nitrogen oxides, remove, wash the table blood and the wall of the cup with water, and cool to room temperature. Transfer to a 1000mL volumetric flask, dilute to the scale with water, and mix well. 1mL of this solution contains 100ug magnesium. 2.5 Magnesium standard solution: Pipette 25.00mL of magnesium standard storage solution (2.4), place it in a 500mL volumetric flask, dilute to the mark with water, and mix. This solution contains 5ug magnesium in 1mL.
3 Instrument
Atomic absorption spectrophotometer with a magnesium hollow cathode lamp. Under the best working conditions of the instrument, any instrument that can meet the following indicators can be used. Minimum sensitivity: The absorbance of the highest concentration standard solution used in the working curve should not be less than 0.30. 1. Draw the linearity of the curve: Divide the working curve into five sections according to the concentration. The ratio of the absorbance difference of the highest section to the absorbance difference of the lowest section should not be less than 0.85.
Minimum Stability: The coefficient of variation of the absorbance of the highest concentration standard solution and the zero concentration solution measured 11 times in the working curve relative to the average absorbance of the highest concentration standard solution should be no less than 1.50% and 0.50% respectively. The calculation of the stability coefficient of variation is shown in Appendix A (Supplement).
Instrument working conditions are shown in Appendix B (Reference). 4 Analysis steps
China Nonferrous Metals Industry Corporation 1988-01~11 Approved 416
19890101 Implementation
4.1 Sample quantity
Weigh 1.000g sample.
4. 2 Blank test
GB 8647.588
Use the zero concentration solution of the standard solution (4.4.2) as the sample blank. 4.3 Determination
4.3.1 Place the sample (4.1) in a clean, uncorroded 400mL beaker. 4.3.2 Add enough water to cover the sample, add 10mL nitric acid (2.2), cover with a beaker, and dissolve the sample. Heat until completely dissolved, wash the beaker and the beaker wall with water, drive off nitrogen oxides with a slight boil, remove, and cool to room temperature. Transfer to a 100mL volumetric flask, dilute to the scale with water, and mix well.
4.3.3 Using an air-acetylene flame, at a wavelength of 285.3nm on an atomic absorption spectrophotometer, adjust to zero with nitric acid (2.3) at the same time as the standard solution series, measure the absorbance of the test solution, subtract the absorbance of the sample blank, and find the corresponding magnesium concentration from the working curve. 4.4 Drawing of working curve
4.4.1 Weigh 1.000g of six portions of nickel metal (2.1) and place them in a 250mL beaker. Then, follow the steps in 4.3.2 and transfer them to 100mL volumetric flasks.
4.4.2 Use a burette to add 0, 1.00, 2.00, 3.00, 4.00, and 5.00mL of magnesium standard solution (2.5) to the volumetric flask (4.4.1), dilute to the mark with water, and mix.
4.4.3 Measure the absorbance of the standard solution (4.4.2) under the same conditions as the sample determination, and subtract the absorbance of the zero concentration solution. Draw the working curve with magnesium concentration as the abscissa and absorbance as the ordinate. 5 Calculation of analysis results
Calculate the percentage of magnesium by the following formula:
Mg(%) = C:V× 10-
Wherein: C--magnesium concentration obtained from the working curve, ug/mL; V----total volume of the test solution, mL;
m--sample volume, g. Www.bzxZ.net
6 Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in the following table. Magnesium content
0. 000 50~ 0. 000 80
>0. 000 8~ 0. 002 0
Allowed
GB8647.5-88
Appendix A
Calculation of stability variation coefficient
(Supplement)
The formula for calculating the coefficient of variation of the absorbance of the highest concentration standard solution and the zero concentration solution is as follows: S
Where: S.
/(0 -0)
The coefficient of variation of the absorbance of the highest concentration standard solution; n
The coefficient of variation of the absorbance of the zero concentration solution relative to the average absorbance of the highest concentration standard solution; the absorbance of the highest concentration standard solution
—the average absorbance of the highest concentration standard solution; Q
The absorbance of the zero concentration solution;
The average absorbance of the zero concentration solution,
-the number of measurements.
GB 8647.5-88
Appendix B
Instrument working conditions
(reference)
The reference working conditions for measuring magnesium using a P-E3030 atomic absorption spectrophotometer are as follows: Wave
Additional notes:
This standard is technically managed by the Beijing Mining Research Institute. Monochromator passband
This standard was drafted by Beijing Research Institute of Mining and Metallurgy and Jinchuan Nonferrous Metals Company. This standard was drafted by Jinchuan Nonferrous Metals Company. The main drafters of this standard are Xin Hanzong and Sun Linggao. Burner height
Air flow rate: B fast
From the implementation of this standard, the original Ministry of Metallurgical Industry Standard YB128-76 "Nickel Chemical Analysis Method" will be invalid. 419
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