This standard specifies the determination method of lead content in tin. This standard is applicable to the determination of lead content in tin. Determination range: 0.00020% to 0.015%. GB/T 3260.4-2000 Chemical analysis method for tin Determination of lead content GB/T3260.4-2000 Standard download decompression password: www.bzxz.net

GR/T 3260.4 -2000
Method 1 "Determination of lead content by catalytic oscillographic polarography" in this standard is the newly added method for determining low lead content in this revision, and the determination range is: 0.00020%0.015%; Method 2 "Determination of lead content by oscillographic polarography" is a reconfirmation of GB/T3260.4--1982% Chemical analysis method of tin by oscillographic polarography". Only a small change was made to the sample amount, and the determination range was adjusted to: >0.015%-0.20%. This standard complies with:
3 Guidelines for standardization work Unit 1: Rules for drafting and expressing standards Part 1: GB/T 1.1- 1993
Basic provisions
GB3/T1.4-1988 Guidelines for standardization work Provisions for the preparation of chemical analysis methods GB/T14671978 General principles and general provisions for chemical analysis methods for metallurgical products (GB/T17433--1998 Basic terminology for chemical analysis of metallurgical products This standard will replace GB/T3260.4-1982 from the date of implementation. This standard was proposed by the State Bureau of Nonferrous Metals Industry. This standard was issued by China The Nonferrous Metals Industry Standard Metrology and Quality Research Institute is responsible for this standard. This standard was drafted by Yunnan Tin Company and Huaxi Group Co., Ltd. This standard was drafted by the smelting branch of Hongnan Tin Co., Ltd. Method 1 of this standard is mainly drafted by Yin Gang, Yang Jun, and Li Zhihong. Method 2 is mainly drafted by Xu Zhixiong, Yin Gang, Yang Jun, 67
1 Scope
National Standard of the People's Republic of China
Chemical analysis method of tinDetermination of lead content
Methods for chemical analysis of tinDetermination of lead contentMethod 1 Determination of lead content by catalytic oscillographic polarography
This standard specifies the method for the determination of lead content in tin. This standard is applicable to the determination of lead content in tin. Determination range: 0.00020%~0.015% 2 Summary of the method
GB/T3260.4-2000
Replacement of GB/T 3260.1982
The sample was dissolved in industrial water, and a large amount of impurities such as tin were removed by volatilization with hydrochloric acid and hydrobromic acid. A quantitative potassium iodide solution was added to the hydrochloric acid-ammonium citrate-ascorbic acid base solution to generate PbI: complex anion with lead, so that it produced a sensitive adsorption catalytic wave. The polarographic determination of lead was carried out at the cathode derivative position of the oscillographic polarograph at -0.52V (vs.SCE). 3 Reagents
3.1 Ascorbic acid.
3.2 Hydrochloric acid (p1.19 g/mL).
3.3 Hydrobromic acid (p1.49 g/mL).
3.4 ​​Nitric acid (pl.42 g/ml.).
3.5 Ammonia water (p0.9 g/ml.)
sulfuric acid (1→4)
3.7hydrochloric acid (1+1).
nitric acid (1+3).
3.9aqua regia: mix 1 volume of nitric acid (3.4) with 3 volumes of hydrochloric acid (3.2). 3.10hydrochloric acid-hydrobromic acid: mix equal volumes of hydrochloric acid (3.2) and hydrobromic acid (3.3) to prepare ammonium citrate solution, weigh 120g citric acid and dissolve it in 500ml. water, add 150ml ammonia water, and then dilute with water to 1000ml, mix well
3.12potassium iodide solution (50g/1.).
3.13 Lead standard stock solution: Weigh 0.5000g of metallic lead (≥99.99%). Place in a 250mL beaker, add 20ml of nitric acid (3.8), heat slightly to dissolve and evaporate to below, cool, add water to dissolve the salt and transfer to a 1000ml volumetric flask. Dilute to scale with water. Mix. This solution contains 0.5mg of lead in 1 ml.
3.14 Lead standard solution: Transfer 20.00ml of lead standard stock solution and add to a 1000ml volumetric flask. Dilute to scale with water. Mix. This solution contains 10μg lead in 1ml.
Approved by the State Administration of Quality and Technical Supervision on August 28, 200068
Implemented on December 1, 2000
4 Analysis steps
4.1 Test sample
Weigh the sample according to Table 1. Accurate to 0.0001g. Lead content,
0, 000 20-~0. 000 50
-0. 000 50-- . 006 0
20. 006 0 -~0. 015
Carry out 2 independent determinations and take the average value. 4.2 Blank test
Carry out a blank test with the test sample.
4.3 Determination
GB/T 3260. 4-2000
Sample address·g
4.3.1 Place the sample (4.1) in a 250ml beaker, cover with a watch glass, add 8~~12ml aqua regia and 0.5ml sulfuric acid, slightly heat to dissolve the sample completely, remove the watch glass, steam until nearly ten, remove, cool slightly, rinse the cup wall with 6~8mL hydrochloric acid and hydrobromic acid, heat until sulfuric acid smokes, repeat the operation 1~3 times to drain all the tin, and cool.
4.3.2 Add 5ml hydrochloric acid (3.7) and blow the cup wall with a small amount of water, slightly heat to dissolve the salts, and cool. Transfer to a 50ml volumetric flask. Wash the beaker 3~1 times with a small amount of water and put it into the volumetric flask. Add 10mL ammonium citrate solution and 0.2g ascorbic acid. Shake to dissolve. Add 5mL potassium iodide solution, dilute to scale with water, and mix. Let stand for 10 min. 4.3.3 Place part of the test solution in an electrolytic cup and scan at the cathode derivative of the three-electrode system of the oscillographic polarograph at a starting potential of 0.31V (vS.SCE), and measure its peak current value at about -0.52V. 4.3.4 Accurately transfer 3 portions of lead standard solution with a lead content close to that of the sample, and add 5ml hydrochloric acid (3.7), 10ml ammonium citrate solution, 0.2g ascorbic acid, and 5mL potassium iodide solution to 50ml volumetric flasks, respectively, and dilute to scale with water and mix. Let stand for 10min. Proceed as in 4.3.3. Measure the peak current value at the same time as the sample. The relative error of the peak current values ​​of the 3 standard solutions shall not be greater than 2%. Take the average value as the peak current value of the standard solution.
5 Expression of analysis results
Calculate the percentage of lead according to formula (1):
Pb(%) V.× 10
Wherein: c-concentration of lead standard solution·ug/mL; I-----peak current value of test solution, uA;
I—-peak current value of lead standard solution, uA; I——-peak current value of empty test solution, uA: V, volume of lead standard solution, nl.;
mass of sample..
The result is expressed to three decimal places. If the lead content is less than 0.010%, it is expressed to four decimal places; if it is less than 0.0010%, it is expressed to five decimal places.
6 Allowable difference
The difference in analysis results between laboratories should not be too large. The allowable difference listed in Table 2, 69
Lead content
0. 000 20~0. 000 50
0. 000 50~- 0. 001 0
0. 001 0---0. 003 0
7 Range
GB/T 3260. 4-2000
Allowable difference
Lead content
>0. 003 0~~0. 006 0
0. 006 0~~0. 010
0. 010-~0. 015
Method 2 Determination of lead content by oscillographic polarography
This standard specifies the method for determining the lead content in tin. This standard is applicable to the determination of the lead content in tin. Determination range: 0.015%-0.20%. 8 Method summary
Additional reagents
The sample is dissolved in aqua regia and volatilized with hydrochloric acid-hydrobromic acid to remove a large amount of tin and other impurities. The reduction wave of lead is determined in a base solution of dilute hydrochloric acid and ammonium citrate. The half-wave potential of lead is 0.46V (vs.SCE). 9 Reagents
9.1 Ascorbic acid.
9.2 Hydrochloric acid (pl.19g/mL).
9.3 Hydrobromic acid (p1.49g/ml.).
9.4 Nitric acid (pl.42g/mL). bZxz.net
Ammonia water (p0.9 g/mL).
Sulfuric acid (1-+4).
Hydrochloric acid (1+1).
Nitric acid (1+3).
Normal water: Mix 1 volume of nitric acid (9.4) with 3 volumes of hydrochloric acid (9.2). Hydrochloric acid-hydrobromic acid: Mix equal volumes of hydrochloric acid (3.2) and oxybromic acid. 9.11
Ammonium citrate solution: Weigh 420g of citric acid and dissolve it in 500mL of water, add 150mL of ammonia water (9.5), dilute to 1000ml with water, and mix.
9.12 Starch solution (10g/L.).
9.13 Copper solution: Weigh 1.34g of copper chloride (CuCl.·2H,O) in a 1000mL beaker, dissolve it with a small amount of water, transfer it to a 1000mL volumetric flask, dilute to the mark with water, and mix. This solution contains about 0.5mg of copper per ml. 9.14 Lead standard solution: Weigh 0.5000g of metallic lead (≥99.99%), place it in a 250mL beaker, add 20ml of nitric acid (9.8). Heat it slightly to dissolve it and evaporate it to dryness, cool it, add water to dissolve the salts. Transfer it to a 1000ml volumetric flask, dilute to the mark with water, and mix it. This solution contains 0.5 mg lead in 1 ml.
10 Analysis steps
10.1 Test sample
Weigh the sample according to Table 1, accurate to 0.0001. 70
Lead content, %
>0.015~0. 050
0. 050-~0. 200
Carry out 2 independent determinations and take the average value. 10.2 Blank test
Carry out a blank test along with the test sample.
10.3 Determination
GB/T 3260. 4--2000
Test Materials
10.3.1 Place the test material (10.1) in a 250ml beaker, cover with table blood, add 8-12ml of normal water and 0.5ml of sulfuric acid, heat slightly to dissolve it completely, remove table III, evaporate to nearly dry, and cool slightly. Add 5-10ml of hydrochloric acid-bromic acid and evaporate until white smoke appears. Repeat this operation 1~~3 times to drain out all the tin, and cool.
10.3.2 Add 3ml of hydrochloric acid (9.7) and blow the wall of the cup with a small amount of water, heat slightly to dissolve the salts, and cool. Add 0.2g of ascorbic acid, shake the beaker to dissolve it, transfer it to a 25ml volumetric flask, rinse the wall of the cup with 5ml of ammonium citrate solution and a small amount of water, and add the washing liquid to the volumetric flask. 10.3.3 Add 2 ml of starch solution, dilute to scale with water and mix well. After standing for about 10 minutes, place part of the test solution in the electrolytic cup and scan at the cathode-polarized conventional position of the three-electrode system of the oscillographic polarograph at the starting potential of -0.2V (vs. SCE). Measure its peak current value at about -(.46V.
10.3.4 Accurately transfer 3 portions of lead standard solution with a lead content close to that of the sample and place them in 3 25ml volumetric flasks, add 3ml of acid (9.7), 0.2g of ascorbic acid, and 5ml of ammonium citrate solution, and proceed as in 10.3.3. Simultaneously with the determination of the sample, measure the peak current value. The relative error of the peak current values ​​of the 3 portions of standard solution shall not be greater than 2%. Take the average value as the peak current value of the standard solution. Note: When the sample contains more than 0.5mg of copper, a corresponding amount of copper solution shall be added to the lead standard solution. 11 Expression of analysis results
Calculate the percentage of lead according to formula (2):
Pb(%) = C Va(I/ - I) × 10
Wherein: c is the concentration of the lead standard solution, mg!rL; I
-the peak current value of the test solution, uA;
I is the peak current value of the lead standard solution.μA;
-the peak current value of the blank test solution, uA; the volume of the lead standard solution, mL;
m. The mass of the sample, g.
-X 100
The result is expressed to two decimal places. If the lead content is less than 0.10%, it is expressed to three decimal places. 12 Allowable difference
The difference in analytical results between laboratories should not be greater than the allowable difference listed in Table 3. Table 3
Lead content
0. 015 ~ 0. 030
*0. 030~0. 050
Allowable difference
Lead content
>0.050--0.10
0.10~0.20
Allowable difference
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