This standard specifies the determination method of cadmium content in tin. This standard is applicable to the determination of cadmium content in tin. Determination range: 0.00001% to 0.0010%. GB/T 3260.11-2000 Chemical analysis method for tin Determination of cadmium content GB/T3260.11-2000 Standard download decompression password: www.bzxz.net

GB/T 3260.1.--2000
This standard is a new standard formulated for the first time.
This standard complies with:
GB/T1.1-1993
Unit 1: Rules for drafting and expressing standards Guidelines for standardization work
Basic provisions
GB/T1.4--1988 Guidelines for standardization work Rules for the preparation of chemical analysis methods GB/T1467--1978 General principles and general provisions for chemical analysis methods for metallurgical products GB/T7728--1987 General principles for flame atomic absorption spectrometry for chemical analysis of metallurgical products GB/T17433--1998 Basic terms for chemical analysis of metallurgical products Appendix A in this standard is a suggestive appendix.
This standard is proposed by the State Bureau of Nonferrous Metals Industry. This standard is under the jurisdiction of the China Nonferrous Metals Industry Standard Metrology and Quality Research Institute. This standard was drafted by Yunnan Tin Company and Liuzhou Huaxi Group Co., Ltd. This standard was drafted by Yunnan Tin Company Research and Design Institute and Liuzhou Huaxi Group Co., Ltd. The main drafters of this standard are: Su Aiping, Wu Yunyuan, Lin Qingquan, Lin Xinzhao, Chen Xufeng. 9.+
Part 1: Standard preparation
1 Scope
National Standard of the People's Republic of China
Methods for chemical analysis of tin--Determination of cadmium content
Methods for chemical analysis of tin--Determination of cadmium content This standard specifies the determination method of cadmium content in tin. This standard is applicable to the determination of cadmium content in tin. Determination range: 0.00001%~0.0010%. 2 Method Summary
GB/T 3260. 11 --2000
After the sample is decomposed with dilute aqua regia in the presence of a small amount of sulfuric acid, tin is removed with hydrochloric acid-hydrobromic acid. In the dilute aqua regia medium, the absorbance of cadmium is measured at a wavelength of 228.80nm using an air-acetylene flame on an atomic absorption spectrometer. 3 Reagents
3.1 Hydrochloric acid (pl.19 g/mL).
3.2 Nitric acid (pl.42g/ml.).
3.3 Nitric acid (1+1).
3.4 ​​Nitric acid (2+3).
3.5 Sulfuric acid (1+1).
3.6 Hydrochloric acid and hydrobromic acid mixture: Mix equal volumes of hydrochloric acid (3.1) and hydrobromic acid (o1.38g/mL) 3.7 Aqua regia: Mix 3 volumes of hydrochloric acid (3.1) and 1 volume of nitric acid (3.2). 3.8 Aqua regia (1+1).
3.9 Standard stock solution: Weigh 0.5000g of metallic cadmium (≥99.99%), place in a 250mL beaker, add 20ml of nitric acid (3.4), cover with Table III, heat slightly until completely dissolved. Wash the table and the wall of the beaker with water, and cool. Transfer to a 500mL volumetric flask, add 25ml of hydrochloric acid (3.1), dilute to the mark with water, and mix. This solution contains 1000ug of cadmium per 1mlL. 3.10 Cadmium standard solution: Pipette 25.00 ml of cadmium standard storage solution into a 250 ml volumetric flask containing 10 ml of hydrochloric acid (3.1). Dilute to the mark with water and mix. This solution contains 100 g of cadmium in 1 ml. 3.11 Standard solution: Pipette 25.00 ml of cadmium standard solution (3.10) into a 250 ml volumetric flask containing 10 ml of hydrochloric acid (3.1). Dilute to the mark with water and mix. This solution contains 10 μg in 1 ml. 4 Instruments
Atomic absorption spectrometer with cadmium hollow cathode lamp. Under the best working conditions of the instrument, any atomic absorption spectrometer that can meet the following indicators can be used. Sensitivity: The characteristic concentration of cadmium should not exceed 0.0090ug/ml. Precision: When the absorbance is measured 11 times with the highest concentration standard solution, the standard deviation should not exceed 1.50% of the average absorbance; when the absorbance is measured 11 times with the lowest concentration standard solution (not the "zero\standard solution"), the standard deviation should not exceed 0.50% of the average absorbance of the highest concentration standard solution.
Approved by the State Administration of Quality and Technical Supervision on August 28, 2000 and implemented on December 1, 2000
GB/T 3260. 11---2000bZxz.net
Linearity of working curve: Divide the working curve into 5 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 0.9.
For instrument working conditions, see Appendix A (Suggested Appendix). 5 Analysis steps
5.1 Test materials
Weigh the sample according to Table 1, accurate to 0.0001g. Table 1
Cadmium content, %
0. 000 01 ~- 0. 000 10
>0. 000 10 ~0. 001 0
Carry out 2 independent determinations and take the average value. 5.2 Blank test
Carry out a blank test with the sample.
5.3 Determination
Sample, instrument
Test solution volume during measurement.mL
5.3.1 Place the sample (5.1) in a 250mL beaker, add 20ml aqua regia (3.8), cover with table blood, decompose completely on a low-temperature electric furnace, remove table III, add 1.0mL sulfuric acid along the wall of the cup, mix, heat and evaporate until white smoke just comes out, and cool slightly. Add 5mL hydrochloric acid-hydrobromic acid mixture along the wall of the cup, mix, heat and evaporate until smoke comes out, and cool slightly. Repeat the addition of hydrochloric acid-hydrobromic acid mixture 2 to 3 times, and after the tin is completely discharged and the smoke is gone, cool. 5.3.2 Add 1.0~ 2.5mL aqua regia (3.7), rinse the cup wall with a small amount of water, heat slightly, cool to room temperature, transfer to a 10-25ml volumetric flask with water containing 10% aqua regia (V/V), dilute to scale, and mix. 5.3.3 Use air-acetylene flame, at a wavelength of 228.80nm on the atomic absorption spectrometer, and when in series with the standard solution, use water to zero to measure the absorbance of the cadmium in the test solution. Subtract the absorbance of the empty test solution from the measured absorbance, and find the corresponding cadmium concentration from the working curve. 5.4 Draw the curve above
Pipette 0.0.50, 1.00, 2.00, 3.00, 4.00, 5.00mL of the thiocyanate standard solution (3.11) and place it in a 100ml volumetric flask. Add 10 mL aqua regia (3.7), dilute to scale with water, mix well. Measure the absorbance of the standard solution under the same conditions as the test sample. Draw a working curve with the pot concentration as the horizontal axis and the absorbance (minus the absorbance of the "zero" concentration standard solution) as the vertical axis. 6 Expression of analysis results
Calculate the percentage of cadmium according to formula (1):
Cd(%) -- c+V. × 10* s
Where: “The concentration of cadmium is obtained from the curve of T. μg/mL.; V is the total volume of the test solution, mL;
-the mass of the test sample,
The result is expressed to four decimal places. If the cadmium content is less than 0.0010%, it is expressed to five decimal places. 7 Allowable difference
The difference in the analysis results between the experimental cases should not be greater than the allowable difference listed in Table 2. 96
0. 000 01 -~ 0. 000 05
≥0. 000 05 ~0. 000 10
>0. 000 10~~0. 000 30
0. 000 30~~0. 000 50
>0. 000 50~ 0. 001 0
CB/T 3260. 11---2000
Allowed amount
0. 000 02
GB/T3260.11—2000
(Appendix of suggestion)
Instrument working conditions
The working conditions for measuring cadmium using WFX-1D atomic absorption spectrometer are shown in Table A1. Table A1
Wavelength, nm
Lamp current, mA
Spectral passband, nm
Burner height, mm
Air flow, L./min
Acetylene flow, l./min
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