GB/T 223.31-2026 Iron, steel and alloy—Determination of arsenic content—spectrophotometric method and iodimetric method English, Anglais, Englisch, Inglés, えいご
WARNING - Persons using this document shall have formal laboratory practice. This standard does not purport to address all of the safety concerns. It is the responsibility of the user to establish appropriate safety and health practices.
1 Scope
This standard describes a method for the determination of the arsenic content in steel, iron and alloy using spectrophotometric method and iodimetric method.
The scope of each method in this document is as follows: Method 1 (distillation separation-molybdenum blue spectrophotometric method) is applicable to the determination of arsenic mass fractions ranging from 0.0005% to 0.10% in iron, steel and alloy; Method 2 (sodium hypophosphite reduction iodimetric method) is applicable to the determination of arsenic mass fractions ranging from 0.010% to 0.65% in pig iron, carbon steel and alloy steel.
2 Normative references
The following documents contain requirements which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 6379.1 Accuracy (trueness and precision) of measurement methods and results - Part 1 : General principles and definitions (GB/T 6379.1-2004, ISO 5725-1:1994, IDT)
GB/T 6379.2 Accuracy (trueness and precision) of measurement methods and results - Part 2: Basic method for the determination of repeatability and reproducibility of a STANDARD measurement method (GB/T 6379.2-2004, ISO 5725-2:1994, IDT)
GB/T 6379.3 Accuracy(trueness and precision) of measurement methods and results - Part 3：Intermediate measures of the precision of a standard measurement method (GB/T 6379.3-2012, ISO 5725-3:1994, IDT)
GB/T 6682 Water for analytical laboratory use - Specification and test methods (GB/T 6682-2008, ISO 3696:1987, MOD)
GB/T 12805 Laboratory glassware - Burettes (GB/T 12805-2011, ISO 385:2005, NEQ)
GB/T 12806 Laboratory glassware - One-mark volumetric flasks (GB/T 12806-2011, ISO 1042:1998, NEQ)
GB/T 12808 Laboratory glassware - One mark pipettes
GB/T 20066 Steel and iron - Sampling and preparation of samples for the determination of chemical composition (ISO 14284:1996, IDT)
3 Terms and definitions
No terms and definitions are specified in this document.
4 Method 1 (distillation separation-molybdenum blue spectrophotometric method)
4.1 Principle
Dissolution of a test portion in a hydrochloric acid and nitric acid mixture. Prolonged heating with sulfuric acid until white fumes are given off. Reduction of arsenic in the presence of hydrazine sulfate and potassium bromide, then separation by distillation as the trivalent chloride, absorbed in the nitric acid solution, in which the As(III) is oxidized back to the pentavalent state As(V). Formation of the molybdenum blue complex between ammonium molybdate and arsenic which is reduced by hydrazine sulfate. Spectrophotometric measurement at a wavelength of 840 nm. Calculation of the mass fraction of arsenic based on the established calibration curve.
4.2 Reagents
During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only grade 3 water specified in GB/T 6682.
4.2.1 Hydrochloric acid
ρ about 1.19 g/mL
4.2.2 Nitric acid
ρ about 1.40 g/mL
4.2.3 Nitric acid (3+1) solution
Add three volumes of nitric acid (4.2.2) to one volume of water.
4.2.4 Acid mixture (1+4)
Add one volume of nitric acid (4.2.2) to four volumes of hydrochloric acid (4.2.1).
4.2.5 Sulfuric acid
ρ about 1.84 g/mL
4.2.6 Sulfuric acid (1+1) solution
While cooling under water and swirling, add a volume of sulfuric acid (4.2.5) to an equal volume of water by several times.
4.2.7 Sulfuric acid (1+6) solution
While cooling under water and swirling, add a volume of sulfuric acid (4.2.5) to six volumes of water by several times.
4.2.8 Mixture of reductant powder
Weigh 2.5 g of hydrazine sulfate and 10 g of potassium bromide, transfer to a mortar and, using a pestle, grind finely and mix well for use.
4.2.9 Ammonium molybdate solution, 10g/L
4.2.10 Hydrazine sulfate solution, 0.6g/L
4.2.11 Arsenic standard solution, 200 μg/mL
Weigh, to the nearest 0.001 g, 0.1320 g of arsenic trioxide. Place in a 100 mL beaker, carefully add 10 mL of nitric acid (4.2.2), cover with a watch glass, heat gently until dissolution is complete. Add 2 mL of sulphuric acid (4.2.6), heat cautiously to expel oxides of nitrogen and then evaporate to dense, white fumes. Remove the beaker from the hot plate, cool somewhat, and wash down the cover and sides of the beaker with a little water. Again evaporate to copious white fumes. Remove, cool and add about 10 mL of water, warm gently until salts are dissolved and the solution becomes clear. Cool to room temperature, transfer the solution quantitatively to a 500 mL one-mark volumetric flask. Dilute to the mark with water and mix.
1 mL of this stock solution contains 200 μg of arsenic.
4.2.12 Arsenic standard solution, 10μg/mL
Contents
Foreword I
Introduction III
1 Scope
2 Normative references
3 Terms and definitions
4 Method 1 (distillation separation-molybdenum blue spectrophotometric method)
5 Method 2 (Sodium hypophosphite reduction iodimetric method)
6 Test report
Annex A (Informative) Components of GB/T 2423
Annex B (Informative) Comparison of clause/subclause numbers between this document and ISO 17058:2004
Annex C (Informative) Additional information on international cooperative tests of Method 1 (distillation separation-molybdenum blue spectrophotometric method)
Annex D (Informative) Precision data of Method 1 in graphical form
Annex E (Informative) Original data of precision test of Method 2 (sodium hypophosphite reduction iodimetric method)
Annex F (Informative) Judgment of measurement results
Standard
GB/T 223.31-2026 Iron, steel and alloy—Determination of arsenic content—spectrophotometric method and iodimetric method (English Version)
Standard No.
GB/T 223.31-2026
Status
to be valid
Language
English
File Format
PDF
Word Count
14500 words
Price(USD)
435.0
Implemented on
2026-9-1
Delivery
via email in 1 business day
Detail of GB/T 223.31-2026
Standard No.
GB/T 223.31-2026
English Name
Iron, steel and alloy—Determination of arsenic content—spectrophotometric method and iodimetric method
GB/T 223.31-2026 Iron, steel and alloy—Determination of arsenic content—spectrophotometric method and iodimetric method English, Anglais, Englisch, Inglés, えいご
WARNING - Persons using this document shall have formal laboratory practice. This standard does not purport to address all of the safety concerns. It is the responsibility of the user to establish appropriate safety and health practices.
1 Scope
This standard describes a method for the determination of the arsenic content in steel, iron and alloy using spectrophotometric method and iodimetric method.
The scope of each method in this document is as follows: Method 1 (distillation separation-molybdenum blue spectrophotometric method) is applicable to the determination of arsenic mass fractions ranging from 0.0005% to 0.10% in iron, steel and alloy; Method 2 (sodium hypophosphite reduction iodimetric method) is applicable to the determination of arsenic mass fractions ranging from 0.010% to 0.65% in pig iron, carbon steel and alloy steel.
2 Normative references
The following documents contain requirements which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 6379.1 Accuracy (trueness and precision) of measurement methods and results - Part 1 : General principles and definitions (GB/T 6379.1-2004, ISO 5725-1:1994, IDT)
GB/T 6379.2 Accuracy (trueness and precision) of measurement methods and results - Part 2: Basic method for the determination of repeatability and reproducibility of a STANDARD measurement method (GB/T 6379.2-2004, ISO 5725-2:1994, IDT)
GB/T 6379.3 Accuracy(trueness and precision) of measurement methods and results - Part 3：Intermediate measures of the precision of a standard measurement method (GB/T 6379.3-2012, ISO 5725-3:1994, IDT)
GB/T 6682 Water for analytical laboratory use - Specification and test methods (GB/T 6682-2008, ISO 3696:1987, MOD)
GB/T 12805 Laboratory glassware - Burettes (GB/T 12805-2011, ISO 385:2005, NEQ)
GB/T 12806 Laboratory glassware - One-mark volumetric flasks (GB/T 12806-2011, ISO 1042:1998, NEQ)
GB/T 12808 Laboratory glassware - One mark pipettes
GB/T 20066 Steel and iron - Sampling and preparation of samples for the determination of chemical composition (ISO 14284:1996, IDT)
3 Terms and definitions
No terms and definitions are specified in this document.
4 Method 1 (distillation separation-molybdenum blue spectrophotometric method)
4.1 Principle
Dissolution of a test portion in a hydrochloric acid and nitric acid mixture. Prolonged heating with sulfuric acid until white fumes are given off. Reduction of arsenic in the presence of hydrazine sulfate and potassium bromide, then separation by distillation as the trivalent chloride, absorbed in the nitric acid solution, in which the As(III) is oxidized back to the pentavalent state As(V). Formation of the molybdenum blue complex between ammonium molybdate and arsenic which is reduced by hydrazine sulfate. Spectrophotometric measurement at a wavelength of 840 nm. Calculation of the mass fraction of arsenic based on the established calibration curve.
4.2 Reagents
During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only grade 3 water specified in GB/T 6682.
4.2.1 Hydrochloric acid
ρ about 1.19 g/mL
4.2.2 Nitric acid
ρ about 1.40 g/mL
4.2.3 Nitric acid (3+1) solution
Add three volumes of nitric acid (4.2.2) to one volume of water.
4.2.4 Acid mixture (1+4)
Add one volume of nitric acid (4.2.2) to four volumes of hydrochloric acid (4.2.1).
4.2.5 Sulfuric acid
ρ about 1.84 g/mL
4.2.6 Sulfuric acid (1+1) solution
While cooling under water and swirling, add a volume of sulfuric acid (4.2.5) to an equal volume of water by several times.
4.2.7 Sulfuric acid (1+6) solution
While cooling under water and swirling, add a volume of sulfuric acid (4.2.5) to six volumes of water by several times.
4.2.8 Mixture of reductant powder
Weigh 2.5 g of hydrazine sulfate and 10 g of potassium bromide, transfer to a mortar and, using a pestle, grind finely and mix well for use.
4.2.9 Ammonium molybdate solution, 10g/L
4.2.10 Hydrazine sulfate solution, 0.6g/L
4.2.11 Arsenic standard solution, 200 μg/mL
Weigh, to the nearest 0.001 g, 0.1320 g of arsenic trioxide. Place in a 100 mL beaker, carefully add 10 mL of nitric acid (4.2.2), cover with a watch glass, heat gently until dissolution is complete. Add 2 mL of sulphuric acid (4.2.6), heat cautiously to expel oxides of nitrogen and then evaporate to dense, white fumes. Remove the beaker from the hot plate, cool somewhat, and wash down the cover and sides of the beaker with a little water. Again evaporate to copious white fumes. Remove, cool and add about 10 mL of water, warm gently until salts are dissolved and the solution becomes clear. Cool to room temperature, transfer the solution quantitatively to a 500 mL one-mark volumetric flask. Dilute to the mark with water and mix.
1 mL of this stock solution contains 200 μg of arsenic.
4.2.12 Arsenic standard solution, 10μg/mL
Contents of GB/T 223.31-2026
Contents
Foreword I
Introduction III
1 Scope
2 Normative references
3 Terms and definitions
4 Method 1 (distillation separation-molybdenum blue spectrophotometric method)
5 Method 2 (Sodium hypophosphite reduction iodimetric method)
6 Test report
Annex A (Informative) Components of GB/T 2423
Annex B (Informative) Comparison of clause/subclause numbers between this document and ISO 17058:2004
Annex C (Informative) Additional information on international cooperative tests of Method 1 (distillation separation-molybdenum blue spectrophotometric method)
Annex D (Informative) Precision data of Method 1 in graphical form
Annex E (Informative) Original data of precision test of Method 2 (sodium hypophosphite reduction iodimetric method)
Annex F (Informative) Judgment of measurement results
