GB/T 223.53-1987 PDF in English
GB/T 223.53-1987 (GB/T223.53-1987, GBT 223.53-1987, GBT223.53-1987)
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Methods for chemical analysis of iron, steel and alloy. The flame atomic absorption spectrophotometric method for the determination of copper content
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Standards related to (historical): GB/T 223.53-1987
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GB/T 223.53-1987: PDF in English (GBT 223.53-1987) GB 223.53-87
GB
NATIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
UDC 669.14/15.543.06
Methods for chemical analysis of iron, steel and alloy -
The flame atomic absorption spectrophotometric
method for the determination of copper content
APPROVED ON. APRIL 03, 1987
IMPLEMENTED ON. MARCH 01, 1988
Approved by. Ministry of Metallurgical Industry
Table of Contents
1 Method summary ... 3
2 Reagent ... 3
3 Instruments ... 4
4 Analytical procedures ... 5
5 Calculation of analysis results ... 6
6 Precision... 6
Additional information ... 8
Methods for chemical analysis of iron, steel and alloy -
The flame atomic absorption spectrophotometric
method for the determination of copper content
This standard applies to the determination of the amount of copper in cast iron,
carbon steel, and low alloy steel. Measuring range is 0. 005% ~ 0. 50%.
This standard follows the requirements GB 1467-78 “Method for chemical
analysis of metallurgy product - General rules and regulations”.
1 Method summary
The sample is decomposed with hydrochloric acid and nitric acid, perchloric
acid is added to evaporate it to produce smoke, AND water is used to dissolve
the salt. The sample solution is sprayed into the air-acetylene flame, and the
copper hollow cathode lamp is used as the light source. The atomic absorption
spectrophotometer is used to measure the absorbance at the wavelength of
324.7 nm.
To eliminate matrix effects, when drawing the calibration curve, it shall add the
iron the amount of which is similar to that of the sample solution.
2 Reagent
2.1 Hydrochloric acid (ρ 1.19g/ml).
2.2 Nitric acid (ρ1.42 g/ml).
2.3 Perchloric acid (ρ1.67 g/ml).
2.4 Perchloric acid (1 + 1).
2.5 Iron solution. WEIGH 10.00 g of high purity iron (copper content of less
than 0.0005%); PLACE it into an 800 ml beaker; ADD 40 of ml hydrochloric
acid (2.1); ADD about 10 ml of nitric acid (2.2) to dissolve it; after it is
completely dissolved, TRANSFER it into a 500 ml volumetric flask; USE water
to dilute it to the mark; MIX it uniformly. AND 1 ml of this solution contains 20
mg of iron.
2.6 Copper standard solution
2.6.1 WEIGH 1.0000 g of pure copper (more than 99.9%); PLACE it into a 400
ml beaker; ADD 30 ml of (1 + 1) nitric acid to dissolve it; after it is completely
dissolved, TRANSFER it into a 1000 ml volumetric flask; USE water to dilute it
to the mark; MIX it uniformly. AND 1 ml of this solution contains 1.0 mg of
copper.
2.6.2 PIPETTE 10.00 ml of copper standard solution (2.6.1); PLACE it into a
100 ml volumetric flask; USE water to dilute it to the mark; MIX it uniformly.
AND 1 ml of this solution contains 100 μg of copper.
3 Instruments
Atomic absorption spectrophotometer, equipped with air-acetylene burner and
copper hollow cathode lamp. Air and acetylene shall be pure enough
(containing no water, oil, or copper) to provide a stable and clear lean flame.
The atomic absorption spectrophotometer used shall reach the following
indicators.
3.1 The minimum precision requirements. The calibration solution of the
highest concentration is used for absorbance measurements for 10 times,
AND the standard deviation shall not exceed 1.0% of the average absorbance;
the calibration solution of the smallest concentration (not zero calibration
solution) is used for absorbance measurements for 10 times, AND its standard
deviation shall not exceed 0.5% of the average absorbance of the calibration
solution of the highest concentration.
3.2 Characteristic concentration. The characteristic concentration of copper in
a solution having a similar matrix with that of the final measurement sample
shall be less than 0.10 μg of copper/ml.
3.3 Detection limit. The detection limit of copper in a solution having a similar
matrix with that of the final measurement sample shall be less than 0.10 μg of
copper/ml.
3.4 Linearity of calibration curves. The ratio of the slope of the upper 20%
concentration range of the calibration curve (expressed as the change in
absorbance) to the slope of the lower 20% concentration range shall be not
less than 0.70.
4 Analytical procedures
4.1 Sample amount
WEIGH 0.5000 g of sample.
4.2 Blank test
MAKE blank test together with the sample.
4.3 Determination
4.3.1 PLACE the sample (4.1) into a 100 ml beaker; ADD 5 ml of hydrochloric
acid (2.1) and 2 ~ 3 ml of nitric acid (2.2); PLACE it on a hot plate to heat to
dissolve it; ADD 5 ml of perchloric acid (2.3); HEAT it until smoke is generated;
TAKE it off to cool it down; ADD 20 ml of water; HEAT to dissolve the salts;
COOL it down; TRANSFER it into a 100 ml volumetric flask; USE water to
dilute it to the mark; MIX it uniformly. If there is precipitation of carbide, silicate,
and so son, they shall be filtered at dry state.
4.3.2 PLACE the sample solution in the atomic absorption spectrophotometer
at a wavelength of 324.7 nm; USE the air-acetylene flame; USE water to adjust
it to zero; MEASURE its absorbance. Combining with the sample solution
absorbance and the absorbance of the blank solution accompanied with the
sample, FIND the concentration (μg/ml) of copper from the calibration curve.
Note. When the amount of copper is less than or equal to 0.10%, USE the
above solution for direct determination. When the amount of copper is greater
than 0.1%, MAKE determination after appropriately diluting it 5 ~ 10 times.
During dilution, it shall keep the original acidity, AND the blank is diluted same
as that of the sample solution.
4.4 Calibration curve drawing
In six 100 ml volumetric flasks, respectively ADD the iron solution (2.5) of the
similar amount with that of the test solution; then respectively ADD 0.00, 1.00,
2.00, 3.00, 4.00, 5.00 OR 0.00, 2.00, 4.00, 6.00, 8.00, 10.00 ml of copper
standard solution (2.6.2); respectively ADD 10 ml of perchloric acid (2.4); USE
water to dilute it to the mark; MIX it uniformly.
At the atomic absorption spectrophotometer at a wavelength of 324.7 nm, USE
the air-acetylene flame; USE water to adjust zero; MEASURE its absorbance.
The absorbance of each solution of the calibration curve series minus the
absorbance of the zero concentration solution is the net absorbance of the
copper calibration curve series solutions. The copper concentration is used as
the abscissa AND the net absorbance as the ordinate, to draw the calibration
curve.
5 Calculation of analysis results
CALCULATE the percentage of copper by the following formula.
Where.
c2 - Concentration of copper in the sample solution as found from the
calibration curve, μg/ml;
c1 - Concentration of copper in the accompanied sample blank solution as
found from the calibration curve, μg/ml;
f - Dilution factor;
V - Volume of the test sample solution, ml;
m0 - Sample amount, g.
6 Precision
Precision table
degree, % (m/m) Repeatability, r Reproducibility, R
0.005 ~ 0.50 lgr = -1.2751 + 0.9225lgm lgR = -1.0637 + 0.9088lgm
Repeatability is the maximum difference of two independent test results of the
same sample at the 95% probability level under normal and correct operating
conditions using this method by the same operator in the same laboratory
using the same instrument in a short period of time.
Reproducibility is the maximum difference of the two independent test results
of the same sample at 95% probability level under normal and correct
operating conditions using this method by two operators in different
laboratories.
If the difference between two independent test results exceeds the
corresponding value of repeatability and reproducibility, the two results are
considered suspect.
Additional information
This standard shall be under the jurisdiction of the Ministry of Metallurgical
Industry Research Institute of Iron and Steel Technology.
This standard was responsibly drafted by the Iron and Steel Research Institute
of the Ministry of Metallurgical Industry.
This standard was drafted by the Iron and Steel Research Institute.
The main drafters of this standard. Yu Fenglian, Li Jinwen.
This standard’s level marking. GB 223.53-87 I.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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