ASTM E350-23

Standard Test Methods for Chemical Analysis of Carbon Steel, Low-Alloy Steel, Silicon Electrical Steel, Ingot Iron, and Wrought Iron

SIGNIFICANCE AND USE
4.1 These test methods for the chemical analysis of metals and alloys are primarily intended as referee methods to test such materials for compliance with compositional specifications, particularly those under the jurisdiction of ASTM Committees A01 on Steel, Stainless Steel, and Related Alloys and A04 on Iron Castings. It is assumed that all who use these test methods will be trained analysts capable of performing common laboratory procedures skillfully and safely. It is expected that work will be performed in a properly equipped laboratory under appropriate quality control practices such as those described in Guide E882.
SCOPE
1.1 These test methods cover the chemical analysis of carbon steels, low-alloy steels, silicon electrical steels, ingot iron, and wrought iron having chemical compositions within the following limits:    
Element  
Composition Range, %  
Aluminum  
0.001 to 1.50  
Antimony  
0.002 to 0.03  
Arsenic  
0.0005 to 0.10  
Bismuth  
0.005 to 0.50  
Boron  
0.0005 to 0.02  
Calcium  
0.0005 to 0.01  
Cerium  
0.005 to 0.50  
Chromium  
0.005 to 3.99  
Cobalt  
0.01 to 0.30  
Columbium (Niobium)  
0.002 to 0.20  
Copper  
0.005 to 1.50  
Lanthanum  
0.001 to 0.30  
Lead  
0.001 to 0.50  
Manganese  
0.01 to 2.50  
Molybdenum  
0.002 to 1.50  
Nickel  
0.005 to 5.00  
Nitrogen  
0.0005 to 0.04  
Oxygen  
0.0001 to 0.03  
Phosphorus  
0.001 to 0.25  
Selenium  
0.001 to 0.50  
Silicon  
0.001 to 5.00  
Sulfur  
0.001 to 0.60  
Tin  
0.002 to 0.10  
Titanium  
0.002 to 0.60  
Tungsten  
0.005 to 0.10  
Vanadium  
0.005 to 0.50  
Zirconium  
0.005 to 0.15  
1.2 The test methods in this standard are contained in the sections indicated as follows:    
Sections  
Aluminum, Total, by the 8-Quinolinol Gravimetric
Method (0.20 % to 1.5 %)  
124–131  
Aluminum, Total, by the 8-Quinolinol
Spectrophotometric Method
(0.003 % to 0.20 %)  
76–86  
Aluminum, Total or Acid-Soluble, by the Atomic
Absorption Spectrometry Method
(0.005 % to 0.20 %)  
308–317  
Antimony by the Brilliant Green Spectrophotometric
Method (0.0002 % to 0.030 %)  
142–151  
Bismuth by the Atomic Absorption Spectrometry
Method (0.02 % to 0.25 %)  
298–307  
Boron by the Distillation-Curcumin
Spectrophotometric Method
(0.0003 % to 0.006 %)  
208–219  
Calcium by the Direct-Current Plasma Atomic
Emission Spectrometry Method
(0.0005 % to 0.010 %)  
289–297  
Carbon, Total, by the Combustion Gravimetric Method
(0.05 % to 1.80 %)—Discontinued 1995  
Cerium and Lanthanum by the Direct Current Plasma
Atomic Emission Spectrometry Method
(0.003 % to 0.50 % Cerium, 0.001 % to 0.30 %
Lanthanum)  
249–257  
Chromium by the Atomic Absorption Spectrometry
Method (0.006 % to 1.00 %)  
220–229  
Chromium by the Peroxydisulfate Oxidation-Titration
Method (0.05 % to 3.99 %)  
230–238  
Cobalt by the Nitroso-R Salt Spectrophotometric
Method (0.01 % to 0.30 %)  
53–62  
Copper by the Sulfide Precipitation-Iodometric
Titration Method (Discontinued 1989)  
87–94  
Copper by the Atomic Absorption Spectrometry
Method (0.004 % to 0.5 %)  
279–288  
Copper by the Neocuproine Spectrophotometric
Method (0.005 % to 1.50 %)  
114–123  
Lead by the Ion-Exchange—Atomic Absorption
Spectrometry Method
(0.001 % to 0.50 %)  
132–141  
Manganese by the Atomic Absorption Spectrometry
Method (0.005 % to 2.0 %)  
269–278  
Manganese by the Metaperiodate Spectrophotometric
Method (0.01 % to 2.5 %)  
9–18  
Manganese by the Peroxydisulfate-Arsenite Titrimetric
Method (0.10 % to 2.50 %)  
164–171  
Molybdenum by the Thiocyanate Spectrophotometric
Method (0.01 % to 1.50 %)  
152–163  
Nickel by the Atomic Absorption Spectrometry
Method (0.003 % to 0.5 %)  
318–327  
Nickel by the Dimethylglyoxim...

General Information

• Status: Published
• Publication Date: 14-Nov-2023
• ICS: 77.040.30 - Chemical analysis of metals
• Technical Committee: E01 - Analytical Chemistry for Metals, Ores, and Related Materials
• Drafting Committee: E01.01 - Iron, Steel, and Ferroalloys

Relations

• Replaces: ASTM E350-18 - Standard Test Methods for Chemical Analysis of Carbon Steel, Low-Alloy Steel, Silicon Electrical Steel, Ingot Iron, and Wrought Iron
• Effective Date: 15-Nov-2023
• Refers: ASTM E352-18e1 - Standard Test Methods for Chemical Analysis of Tool Steels and Other Similar Medium- and High-Alloy Steels
• Effective Date: 01-Jul-2018
• Referred By: ASTM D3724-01(2019) - Standard Specification for Synthetic Brown Iron Oxide Pigment
• Effective Date: 15-Nov-2023
• Referred By: ASTM B564-22 - Standard Specification for Nickel Alloy Forgings
• Effective Date: 15-Nov-2023
• Referred By: ASTM E1282-21 - Standard Guide for Specifying the Chemical Compositions and Selecting Sampling Practices and Quantitative Analysis Methods for Metals, Ores, and Related Materials
• Effective Date: 15-Nov-2023
• Referred By: ASTM A861-04(2023) - Standard Specification for High-Silicon Iron Pipe and Fittings
• Effective Date: 15-Nov-2023
• Referred By: ASTM B848/B848M-21 - Standard Specification for Powder Forged (PF) Ferrous Materials
• Effective Date: 15-Nov-2023
• Referred By: ASTM E1473-22 - Standard Test Methods for Chemical Analysis of Nickel, Cobalt, and High-Temperature Alloys
• Effective Date: 15-Nov-2023
• Referred By: ASTM C114-23 - Standard Test Methods for Chemical Analysis of Hydraulic Cement
• Effective Date: 15-Nov-2023
• Referred By: ASTM A713-04(2017) - Standard Specification for Steel Wire, High-Carbon Spring, for Heat-Treated Components
• Effective Date: 15-Nov-2023
• Referred By: ASTM E352-23 - Standard Test Methods for Chemical Analysis of Tool Steels and Other Similar Medium- and High-Alloy Steels
• Effective Date: 15-Nov-2023
• Referred By: ASTM C1797-23a - Standard Specification for Ground Calcium Carbonate and Aggregate Mineral Fillers for use in Hydraulic Cement Concrete
• Effective Date: 15-Nov-2023
• Referred By: ASTM E2093-12(2016) - Standard Guide for Optimizing, Controlling and Assessing Test Method Uncertainties from Multiple Workstations in the Same Laboratory Organization
• Effective Date: 15-Nov-2023
• Referred By: ASTM E353-19e1 - Standard Test Methods for Chemical Analysis of Stainless, Heat-Resisting, Maraging, and Other Similar Chromium-Nickel-Iron Alloys
• Effective Date: 15-Nov-2023
• Referred By: ASTM A751-21 - Standard Test Methods and Practices for Chemical Analysis of Steel Products
• Effective Date: 15-Nov-2023

Overview

ASTM E350-23: Standard Test Methods for Chemical Analysis of Carbon Steel, Low-Alloy Steel, Silicon Electrical Steel, Ingot Iron, and Wrought Iron is a primary reference for laboratories and industries performing chemical compositional analysis of ferrous metals. Developed by ASTM International, this standard outlines reliable, referee test methods critical for ensuring that materials meet compositional specifications, particularly for compliance with standards overseen by ASTM Committees A01 and A04.

This document is designed for use by skilled analysts operating in well-equipped laboratories, following established quality control procedures as specified in related guides like ASTM E882. The test methods included ensure accuracy and repeatability in analyzing a broad range of metallic elements in various steels and iron products.

Key Topics

• Scope and Coverage: The standard applies to the chemical analysis of carbon steels, low-alloy steels, silicon electrical steels, ingot iron, and wrought iron with elemental composition ranges covering aluminum, antimony, arsenic, bismuth, boron, calcium, cerium, chromium, cobalt, niobium, copper, lanthanum, lead, manganese, molybdenum, nickel, nitrogen, oxygen, phosphorus, selenium, silicon, sulfur, tin, titanium, tungsten, vanadium, and zirconium.

• Test Methods Included:

  • Gravimetric Methods: Quantitative measurement based on the mass of specific compounds.
  • Spectrophotometric Methods: Use of light absorption to determine element concentration.
  • Atomic Absorption/Emission Spectrometry: Measurement of elements by detecting absorbed or emitted light in an atomic state.
  • Titrimetric Methods: Volumetric techniques for analyzing chemical composition.

• Selection Criteria: Multiple methods are provided for several elements due to varying composition ranges. Users must match method applicability to alloy composition and consider interference and scope limitations.

• Analytical Quality and Safety: The standard emphasizes purity of reagents, apparatus requirements, and lab safety practices, in accordance with referenced documents such as ASTM E50 and D1193.

Applications

ASTM E350-23 is vital in a wide range of practical scenarios, including:

• Quality Control in Metallurgy: Essential for steel producers and processors to verify product compliance with precise chemical composition limits, ensuring the desired material properties and performance.
• Referee and Certification Analyses: Used by third-party laboratories and certifying bodies to resolve disputes or confirm compositional specifications during procurement, manufacturing, or regulatory review.
• Research and Development: Supporting innovation and process optimization for new steel and iron alloys by providing robust, validated analytical protocols.
• Regulatory Compliance: Often required for conformity with industry standards, customer specifications, and governmental regulations, especially in sectors such as construction, automotive, electrical, and defense.

Related Standards

ASTM E350-23 references and is complemented by several other key standards, including:

• ASTM E351 - Chemical Analysis of Cast Iron
• ASTM E352 - Analysis of Tool Steels
• ASTM E353 - Analysis of Stainless, Heat-Resisting, and Chromium-Nickel-Iron Alloys
• ASTM E354 - Analysis of High-Temperature, Electrical, Magnetic, and Similar Alloys
• ASTM E1019 - Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt Alloys
• ASTM E882 - Quality Control in the Chemical Analysis Laboratory
• ISO 5725 - Determination of Repeatability and Reproducibility for Laboratory Tests
• Practice E1806 - Sampling Steel and Iron for Chemical Composition

These standards collectively ensure comprehensive, accurate, and repeatable chemical analysis throughout the steel and iron industry.

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Keywords: ASTM E350-23, chemical analysis, carbon steel, low-alloy steel, silicon steel, ingot iron, wrought iron, spectrophotometric method, gravimetric method, atomic absorption, referee methods, compositional analysis, metallurgical quality control.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E350 − 23
Standard Test Methods for
Chemical Analysis of Carbon Steel, Low-Alloy Steel, Silicon
Electrical Steel, Ingot Iron, and Wrought Iron
This standard is issued under the fixed designation E350; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
Sections
1.1 These test methods cover the chemical analysis of
Aluminum, Total, by the 8-Quinolinol 76–86
carbon steels, low-alloy steels, silicon electrical steels, ingot Spectrophotometric Method
(0.003 % to 0.20 %)
iron, and wrought iron having chemical compositions within
Aluminum, Total or Acid-Soluble, by the Atomic 308–317
the following limits:
Absorption Spectrometry Method
(0.005 % to 0.20 %)
Element Composition Range, %
Antimony by the Brilliant Green Spectrophotometric 142–151
Aluminum 0.001 to 1.50
Method (0.0002 % to 0.030 %)
Antimony 0.002 to 0.03
Bismuth by the Atomic Absorption Spectrometry 298–307
Arsenic 0.0005 to 0.10
Method (0.02 % to 0.25 %)
Bismuth 0.005 to 0.50
Boron by the Distillation-Curcumin 208–219
Boron 0.0005 to 0.02
Spectrophotometric Method
Calcium 0.0005 to 0.01
(0.0003 % to 0.006 %)
Cerium 0.005 to 0.50
Calcium by the Direct-Current Plasma Atomic 289–297
Chromium 0.005 to 3.99
Emission Spectrometry Method
Cobalt 0.01 to 0.30
(0.0005 % to 0.010 %)
Columbium (Niobium) 0.002 to 0.20
Carbon, Total, by the Combustion Gravimetric Method
Copper 0.005 to 1.50
(0.05 % to 1.80 %)—Discontinued 1995
Lanthanum 0.001 to 0.30
Cerium and Lanthanum by the Direct Current Plasma 249–257
Lead 0.001 to 0.50
Atomic Emission Spectrometry Method
Manganese 0.01 to 2.50
(0.003 % to 0.50 % Cerium, 0.001 % to 0.30 %
Molybdenum 0.002 to 1.50
Lanthanum)
Nickel 0.005 to 5.00
Chromium by the Atomic Absorption Spectrometry 220–229
Nitrogen 0.0005 to 0.04
Method (0.006 % to 1.00 %)
Oxygen 0.0001 to 0.03
Chromium by the Peroxydisulfate Oxidation-Titration 230–238
Phosphorus 0.001 to 0.25
Method (0.05 % to 3.99 %)
Selenium 0.001 to 0.50
Cobalt by the Nitroso-R Salt Spectrophotometric 53–62
Silicon 0.001 to 5.00
Method (0.01 % to 0.30 %)
Sulfur 0.001 to 0.60
Copper by the Sulfide Precipitation-Iodometric 87–94
Tin 0.002 to 0.10
Titration Method (Discontinued 1989)
Titanium 0.002 to 0.60
Copper by the Atomic Absorption Spectrometry 279–288
Tungsten 0.005 to 0.10
Method (0.004 % to 0.5 %)
Vanadium 0.005 to 0.50
Copper by the Neocuproine Spectrophotometric 114–123
Zirconium 0.005 to 0.15
Method (0.005 % to 1.50 %)
1.2 The test methods in this standard are contained in the Lead by the Ion-Exchange—Atomic Absorption 132–141
Spectrometry Method
sections indicated as follows:
(0.001 % to 0.50 %)
Sections Manganese by the Atomic Absorption Spectrometry 269–278
Method (0.005 % to 2.0 %)
Aluminum, Total, by the 8-Quinolinol Gravimetric 124–131 Manganese by the Metaperiodate Spectrophotometric 9–18
Method (0.20 % to 1.5 %) Method (0.01 % to 2.5 %)
Manganese by the Peroxydisulfate-Arsenite Titrimetric 164–171
Method (0.10 % to 2.50 %)
Molybdenum by the Thiocyanate Spectrophotometric 152–163
These test methods are under the jurisdiction of ASTM Committee E01 on
Method (0.01 % to 1.50 %)
Analytical Chemistry for Metals, Ores, and Related Materials and are the direct
Nickel by the Atomic Absorption Spectrometry 318–327
responsibility of Subcommittee E01.01 on Iron, Steel, and Ferroalloys.
Method (0.003 % to 0.5 %)
Current edition approved Nov. 15, 2023. Published December 2023. Originally
Nickel by the Dimethylglyoxime Gravimetric 180–187
approved in 1968. Last previous edition approved in 2018 as E350 – 18. DOI:
Method (0.1 % to 5.00 %)
10.1520/E0350-23.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E350 − 23
E29 Practice for Using Significant Digits in Test Data to
Sections
Determine Conformance with Specifications
Nickel by the Ion-Exchange-Atomic-Absorption 188–197
E50 Practices for Apparatus, Reagents, and Safety Consid-
Spectrometry Method
(0.005 % to 1.00 %) erations for Chemical Analysis of Metals, Ores, and
Nitrogen by the Distillation-Spectrophotometric 63–75
Related Materials
Method (Discontinued 1988)
E60 Practice for Analysis of Metals, Ores, and Related
Phosphorus by the Alkalimetric Method 172–179
Materials by Spectrophotometry
(0.02 % to 0.25 %)
Phosphorus by the Molybdenum Blue 19–30
E135 Terminology Relating to Analytical Chemistry for
Spectrophotometric Method
Metals, Ores, and Related Materials
(0.003 % to 0.09 %)
Silicon by the Molybdenum Blue Spectrophotometric 103–113 E173 Practice for Conducting Interlaboratory Studies of
Method (0.01 % to 0.06 %)
Methods for Chemical Analysis of Metals (Withdrawn
Silicon by the Gravimetric Titration 46–52
1997)
Method (0.05 % to 3.5 %)
Sulfur by the Gravimetric Method 31–36 E351 Test Methods for Chemical Analysis of Cast Iron—All
(Discontinued 1988)
Types
Sulfur by the Combustion-Iodate Titration Method 37–45
E352 Test Methods for Chemical Analysis of Tool Steels and
(0.005 % to 0.3 %) (Discontinued 2017)
Tin by the Sulfide Precipitation-Iodometric Titration 95–102 Other Similar Medium- and High-Alloy Steels
Method (0.01 % to 0.1 %)
E353 Test Methods for Chemical Analysis of Stainless,
Tin by the Solvent Extraction-Atomic Absorption 198–207
Heat-Resisting, Maraging, and Other Similar Chromium-
Spectrometry Method
(0.002 % to 0.10 %)
Nickel-Iron Alloys
Titanium by the Diantipyrylmethane 258–268
E354 Test Methods for Chemical Analysis of High-
Spectrophotometric Method
Temperature, Electrical, Magnetic, and Other Similar Iron,
(0.025 % to 0.30 %)
Vanadium by the Atomic Absorption Spectrometry 239–248
Nickel, and Cobalt Alloys
Method (0.006 % to 0.15 %)
E882 Guide for Accountability and Quality Control in the
1.3 Test methods for the determination of several elements
Chemical Analysis Laboratory
not included in this standard can be found in Test Methods
E1019 Test Methods for Determination of Carbon, Sulfur,
E1019.
Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt
Alloys by Various Combustion and Inert Gas Fusion
1.4 Some of the composition ranges given in 1.1 are too
Techniques
broad to be covered by a single test method and therefore this
E1024 Guide for Chemical Analysis of Metals and Metal
standard contains multiple test methods for some elements.
Bearing Ores by Flame Atomic Absorption Spectropho-
The user must select the proper test method by matching the
tometry (Withdrawn 2004)
information given in the Scope and Interference sections of
E1601 Practice for Conducting an Interlaboratory Study to
each test method with the composition of the alloy to be
Evaluate the Performance of an Analytical Method
analyzed.
E1806 Practice for Sampling Steel and Iron for Determina-
1.5 The values stated in SI units are to be regarded as
tion of Chemical Composition
standard. In some cases, exceptions allowed in IEEE/ASTM SI
IEEE/ASTM SI 10 Standard for Use of the International
10 are also used.
System of Units (SI): The Modern Metric System
1.6 This standard does not purport to address all of the
2.2 ISO Standard:
safety concerns, if any, associated with its use. It is the
ISO 5725 Precision of Test Methods—Determination of
responsibility of the user of this standard to establish appro-
Repeatability and Reproducibility for Inter-Laboratory
priate safety, health, and environmental practices and deter-
Tests
mine the applicability of regulatory limitations prior to use.
Specific hazards statements are given in Section 6 and in
3. Terminology
special “Warning” paragraphs throughout these test methods.
3.1 For definitions of terms used in these test methods, refer
1.7 This international standard was developed in accor-
to Terminology E135.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4. Significance and Use
Development of International Standards, Guides and Recom-
4.1 These test methods for the chemical analysis of metals
mendations issued by the World Trade Organization Technical
and alloys are primarily intended as referee methods to test
Barriers to Trade (TBT) Committee.
such materials for compliance with compositional
2. Referenced Documents
specifications, particularly those under the jurisdiction of
ASTM Committees A01 on Steel, Stainless Steel, and Related
2.1 ASTM Standards:
Alloys and A04 on Iron Castings. It is assumed that all who use
D1193 Specification for Reagent Water
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or The last approved version of this historical standard is referenced on
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM www.astm.org.
Standards volume information, refer to the standard’s Document Summary page on Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
E350 − 23
these test methods will be trained analysts capable of perform- Method, unless an alternative rounding method is specified by
ing common laboratory procedures skillfully and safely. It is the customer or applicable material specification.
expected that work will be performed in a properly equipped
laboratory under appropriate quality control practices such as
MANGANESE BY THE METAPERIODATE
those described in Guide E882.
SPECTROPHOTOMETRIC METHOD
5. Apparatus, Reagents, and Instrumental Practices
9. Scope
5.1 Apparatus—Specialized apparatus requirements are
9.1 This test method covers the determination of manganese
listed in the “Apparatus” Section in each test method.
from 0.01 % to 2.5 %.
5.1.1 In the methods specifying spectrophotometric testing,
the cells utilized to contain the reference material solutions and
10. Summary of Test Method
the sample solutions in spectrophotometers are referred to as
10.1 Manganous ions are oxidized to permanganate ions by
“absorption cells.” Please note that the radiant energy passed
reaction with metaperiodate ions. Solutions of the samples are
through the cells can be measured as absorbance or transmit-
fumed with HClO so that the effect of metaperiodate ion is
tance. These methods refer to absorbance measurements. Refer
limited to the oxidation of manganese. Spectrophotometric
to Practice E60 for details.
absorbance measurement is made at 545 nm.
5.2 Reagents:
11. Concentration Range
5.2.1 Purity of Reagents—Reagent grade chemicals shall be
used in all tests. Unless otherwise indicated, all reagents used
11.1 The recommended concentration range is from 0.15
in these test methods shall conform to the specifications of the
mg to 0.8 mg of manganese per 50 mL of solution, using a
Committee on Analytical Reagents of the American Chemical
1-cm cell (Note 1) and a spectrophotometer with a band width
Society where such specifications are available. Other chemi-
of 10 nm or less.
cals may be used, provided it is first ascertained that they are
NOTE 1—This test method has been written for cells having a 1-cm light
of sufficiently high purity to permit their use without adversely
path and a “narrow-band” instrument. The concentration range depends
affecting the expected performance of the determination, as
upon band width and spectral region used as well as cell optical path
indicated in the Precision and Bias section. length. Cells having other dimensions may be used, provided suitable
adjustments can be made in the amounts of sample and reagents used.
5.2.2 Purity of Water—Unless otherwise indicated, refer-
ences to water shall mean reagent water conforming to Type I
12. Stability of Color
D1193. Type III or IV may be used
or Type II of Specification
12.1 The color is stable for at least 24 h.
if they effect no measurable change in the blank or sample.
13. Interferences
6. Hazards
13.1 The elements ordinarily present do not interfere.
6.1 For precautions to be observed in the use of certain
HClO treatment, which is used in the procedure, yields
reagents and equipment in these test methods, refer to Practices
solutions which can be highly colored due to the presence of Cr
E50.
(VI) ions. Although these ions and other colored ions in the
sample solution undergo no further change in color quality
7. Sampling
upon treatment with metaperiodate ion, the following precau-
7.1 For procedures to sample the material, refer to Practice
tions must be observed when filter spectrophotometers are
E1806.
used: Select a filter with maximum transmittance between 545
nm and 565 nm. The filter must transmit not more than 5 % of
8. Interlaboratory Studies and Rounding Calculated
its maximum at a wavelength shorter than 530 nm. The band
Values
width of the filter should be less than 30 nm when measured at
8.1 These test methods have been evaluated using Practice
50 % of its maximum transmittance. Similar restrictions apply
E173 or ISO 5725.
with respect to the wavelength region employed when other
8.1.1 Practice E173 has been replaced by Practice E1601.
“wide-band” instruments are used.
The reproducibility, R , of Practice E173 corresponds to the
13.2 The spectral transmittance curve of permanganate ions
reproducibility index, R, of Practice E1601. The repeatability,
exhibits two useful minima, one at approximately 526 nm, and
R , of Practice E173 corresponds to the repeatability index, r,
the other at 545 nm. The latter is recommended when a
of Practice E1601.
“narrow-band” spectrophotometer is used.
8.2 Rounding of test results obtained using these test meth-
14. Reagents
ods shall be performed as directed in Practice E29, Rounding
14.1 Manganese, Standard Solution (1 mL = 0.032 mg
Mn)—Transfer the equivalent of 0.4000 g of assayed, high-
Reagent Chemicals, American Chemical Society Specifications, American
purity manganese (purity: 99.99 % minimum), to a 500-mL
Chemical Society, Washington, DC, www.acs.org. For suggestions on the testing of
volumetric flask and dissolve in 20 mL of HNO by heating.
reagents not listed by the American Chemical Society, see the United States
Cool, dilute to volume, and mix. Using a pipet, transfer 20 mL
Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc.
(USPC), Rockville, MD, http://www.usp.org. to a 500-mL volumetric flask, dilute to volume, and mix.
E350 − 23
14.2 Nitric-Phosphoric Acid Mixture—Cautiously, while
Sample Tolerance in Aliquot
Manganese, Mass, Sample Mass, Dilution, Volume,
stirring, add 100 mL of HNO and 400 mL of H PO to 400
3 3 4
% g mg mL mL
mL of water. Cool, dilute to 1 L, and mix. Prepare fresh as
0.01 to 0.5 0.80 0.5 100 20
needed. 0.45 to 1.0 0.35 0.3 100 20
0.85 to 2.0 0.80 0.5 500 20
14.3 Potassium Metaperiodate Solution (7.5 g/L)—Dissolve
1.95 to 2.5 0.80 0.5 500 10
7.5 g of potassium metaperiodate (KIO ) in 200 mL of hot
4 Transfer the sample to a 100-mL or 500-mL borosilicate
HNO (1 + 1), add 400 mL of H PO , cool, dilute to 1 L, and
3 3 4
glass volumetric flask as directed in the above table or to a
mix.
300-mL Erlenmeyer flask if HF is to be used in sample
dissolution.
14.4 Water, Pretreated with Metaperiodate—Add 20 mL of
16.1.2 To dissolve samples that do not require HF, add 8 mL
KIO solution to 1 L of water, mix, heat at not less than 90 °C
to 10 mL of HCl (1 + 1), and heat. Add HNO as needed to
for 20 min to 30 min, and cool. Use this water to dilute
hasten dissolution, and then add 3 mL to 4 mL in excess. When
solutions to volume that have been treated with KIO solution
dissolution is complete, cool, then add 10 mL of HClO ;
to oxidize manganese, and thus avoid reduction of permangan-
evaporate to fumes to oxidize chromium, if present, and to
ate ions by any reducing agents in the untreated water.
expel HCl. Continue fuming until salts begin to separate. Cool,
Caution—Avoid the use of this water for other purposes.
add 50 mL of water, and digest if necessary to dissolve the
salts. Cool and transfer the solution to either a 100-mL or
15. Preparation of Calibration Curve
500-mL volumetric flask as indicated in 16.1.1. Proceed to
15.1 Calibration Solutions—Using pipets, transfer (5, 10,
16.1.4.
15, 20, and 25) mL of manganese standard solution (1 mL =
16.1.3 For samples whose dissolution is hastened by HF,
0.032 mg Mn) to 50-mL borosilicate glass volumetric flasks,
treat them in a 300-mL Erlenmeyer flask by adding 8 mL to 10
and, if necessary, dilute to approximately 25 mL. Proceed as
mL of HCl (1 + 1), and heating. Add HNO and a few drops of
directed in 15.3.
HF as needed to hasten dissolution, and then add 3 mL to 4 mL
of HNO . When dissolution is complete, cool, then add 10 mL
15.2 Reference Solution—Transfer approximately 25 mL of
of HClO , evaporate to fumes to oxidize chromium, if present,
water to a 50-mL borosilicate glass volumetric flask. Proceed 4
and to expel HCl. Continue fuming until salts begin to separate.
as directed in 15.3.
Cool, add 50 mL of water, digest if necessary to dissolve the
15.3 Color Development—Add 10 mL of KIO solution,
salts, cool, and transfer the solution to either a 100-mL or
and heat the solutions at not less than 90 °C for 20 min to 30
500-mL volumetric flask as indicated in 16.1.1.
min (Note 2). Cool, dilute to volume with pretreated water, and
16.1.4 Cool the solution to room temperature, dilute to
mix.
volume, and mix. Allow insoluble matter to settle, or dry-filter
through a coarse paper and discard the first 15 mL to 20 mL of
NOTE 2—Immersing the flasks in a boiling water bath is a preferred
the filtrate, before taking aliquots.
means of heating them for the specified period to ensure complete color
development.
16.1.5 Using a pipet, transfer 10 mL to 20 mL aliquots, as
directed in 16.1.1, to two 50-mL borosilicate glass volumetric
15.4 Spectrophotometry:
flasks. Treat one portion as directed in 16.3. Treat the other
15.4.1 Multiple-Cell Spectrophotometer—Measure the cell
portion as directed in 16.4.1.
correction using the Reference Solution (15.2) in absorption
cells with a 1-cm light path and using a light band centered at 16.2 Reagent Blank Solution—Carry a reagent blank
545 nm. Using the test cell, take the spectrophotometric through the entire procedure using the same amounts of all
absorbance readings of the calibration solutions versus the reagents with the sample omitted.
reference solution (15.2).
16.3 Color Development—Proceed as directed in 15.3.
15.4.2 Single-Cell Spectrophotometer—Transfer a suitable
16.4 Reference Solutions:
portion of the reference solution (15.2) to an absorption cell
16.4.1 Background Color Solution—To one of the sample
with a 1-cm light path and adjust the spectrophotometer to the
aliquots in a 50-mL volumetric flask, add 10 mL of nitric-
initial setting, using a light band centered at 545 nm. While
phosphoric acid mixture, and heat the solution at not less than
maintaining this adjustment, take the spectrophotometric ab-
90 °C for 20 min to 30 min (Note 2 in 15.3). Cool, dilute to
sorbance readings of the calibration solutions.
volume (with untreated water), and mix.
15.5 Calibration Curve—Follow the instrument manufac-
16.4.2 Reagent Blank Reference Solution—Transfer the re-
turer’s instructions for generating the calibration curve. Plot
agent blank solution (16.2) to the same size volumetric flask as
the net spectrophotometric absorbance readings of the calibra-
used for the test solutions and transfer the same size aliquots as
tion solutions against milligrams of manganese per 50 mL of
used for the test solutions to two 50-mL volumetric flasks.
solution.
Treat one portion as directed in 16.3 and use as reference
solution for test samples. Treat the other as directed in 16.4.1
16. Procedure
and use as reference solution for Background Color Solutions.
16.1 Test Solution:
16.5 Spectrophotometry—Establish the cell corrections with
16.1.1 Select and weigh a sample as follows: the reagent blank reference solution to be used as a reference
E350 − 23
solution for background color solutions. Take the spectropho- 20. Summary of Test Method
tometric absorbance readings of the Background Color Solu-
20.1 The sample is dissolved in mixed acids and the
tions and the test solutions versus the respective Reagent Blank
solution is fumed with HClO . Ammonium molybdate is added
Reference Solutions as directed in15.4.
to react with the phosphorus to form the heteropoly phospho-
molybdate. This species is then reduced with hydrazine sulfate
17. Calculation
to form the molybdenum blue complex. Spectrophotometric
17.1 Convert the net spectrophotometric absorbance reading
absorbance measurement is made at 650 nm or 825 nm,
of the test solution and of the background color solution to
depending upon the concentration.
milligrams of manganese by means of the calibration curve.
Calculate the percent of manganese as follows:
21. Concentration Range
Manganese, % 5 A 2 B / C × 10 (1)
~ ! ~ !
21.1 The recommended concentration range is from 0.005
mg to 0.05 mg of phosphorus per 100 mL of solution when
where:
measured at 825 nm and from 0.05 mg to 0.3 mg of phosphorus
A = manganese found in 50 mL of the final test solution, mg,
per 100 mL of solution when measured at 650 nm, using a
B = apparent manganese found in 50 mL of the final
1-cm cell.
background color solution, mg, and
C = sample represented in 50 mL of the final test solution, g.
NOTE 3—This test method has been written for cells having a 1-cm light
path. Cells having other dimensions may be used, provided suitable
adjustments can be made in the amounts of sample and reagents used.
18. Precision and Bias
18.1 Precision—Nine laboratories cooperated in testing this
22. Stability of Color
test method and obtained the data summarized in Table 1.
22.1 The molybdenum blue complex is stable for at least 2
Although a sample covered by this test method with manga-
h.
nese composition of approximately 2.5 % was not available,
the precision data for this composition should be similar to
23. Interferences
those obtained for Material 7.
23.1 None of the elements usually present interfere except
18.2 Bias—The accuracy of this test method has been
deemed satisfactory based upon the data for the certified arsenic, which is removed by volatilization as the bromide.
reference materials in Table 1. Users are encouraged to use
these or similar reference materials to verify that the test 24. Apparatus
method is performing accurately in their laboratories.
24.1 Glassware must be phosphorus and arsenic-free. Boil
the glassware with HCl and rinse with water before use. It is
recommended that the glassware used for this determination be
PHOSPHORUS BY THE MOLYBDENUM BLUE
reserved for this use only. Many detergents contain phosphorus
SPECTROPHOTOMETRIC METHOD
and must not be used for cleaning purposes.
19. Scope
25. Reagents
19.1 This test method covers the determination of phospho-
25.1 Ammonium Molybdate Solution (20 g/L)—Cautiously,
rus from 0.003 % to 0.09 %.
while stirring and cooling, add 300 mL of H SO to 500 mL of
2 4
19.2 The upper limit of the scope has been set at 0.09 %
water and cool. Add 20 g of ammonium heptamolybdate
because sufficient numbers of test materials containing higher
((NH ) Mo O ·4H O), cautiously dilute to 1 L, and mix.
4 6 7 24 2
phosphorus contents were unavailable for testing as directed in
Practice E173. However, recognizing that the chemical prin- 25.2 Ammonium Molybdate-Hydrazine Sulfate Solution—
ciples used in this test method are capable of handling higher Dilute 250 mL of the ammonium molybdate solution to 600
compositions, the test method includes a calibration procedure mL, add 100 mL of the hydrazine sulfate solution, dilute to 1
up to 0.25 %. Users of this test method are cautioned that its L, and mix. Do not use a solution that has stood for more than
use above 0.09 % is not supported by interlaboratory testing. 1 h.
TABLE 1 Statistical Information—Manganese—Metaperiodate Spectrophotometric Method
Manganese Found, Repeatability Reproducibility
Test Material
% (R , E173) (R , E173)
1 2
1. Alloy steel (BCS 252, 0.016 Mn) 0.022 0.004 0.006
2. Alloy steel (BCS 255/1 0.16 Mn) 0.161 0.004 0.010
3. Low-alloy steel (NIST 72f, 0.545 Mn) 0.551 0.010 0.020
4. Low-alloy steel (NIST 139a, 0.780 Mn) 0.780 0.009 0.030
5. Alloy steel (NIST, 159, 0.807 Mn) 0.819 0.010 0.034
6. Carbon steel (NIST 13f, 0.889 Mn) 0.892 0.015 0.027
7. Low-alloy steel (NIST 100b, 1.89 Mn) 1.91 0.02 0.04
E350 − 23
25.3 Hydrazine Sulfate Solution (1.5 g/L)—Dissolve 1.5 g the net spectrophotometric absorbance readings of the calibra-
of hydrazine sulfate ((NH ) ·H SO ) in water, dilute to 1 L, tion solutions against milligrams of phosphorus per 100 mL of
2 2 2 4
and mix. Discard any unused solution after 24 h. solution.
25.4 Phosphorus Standard Solution A (1 mL = 1.0 mg
27. Preparation of Calibration Curve for Concentrations
P)—Transfer 2.292 g of anhydrous disodium hydrogen phos-
from 0.05 mg/100 mL to 0.30 mg/100 mL
phate (Na HPO ), previously dried to constant mass at 105 °C,
2 4
27.1 Calibration Solutions—Using pipets, transfer (5, 10,
to a 500-mL volumetric flask; dissolve in about 100 mL of
water, dilute to volume, and mix. 15, 20, 25, and 30) mL of Phosphorus Standard Solution C (1
mL = 0.10 mg P) to 100-mL volumetric flasks. Add 20 mL of
25.5 Phosphorus Standard Solution B (1 mL = 0.01 mg
HClO , dilute to volume, and mix. Using a pipet, transfer 10
P)—Using a pipet, transfer 10 mL of Solution A (1 mL = 1.0
mL of each solution to a 100-mL borosilicate glass volumetric
mg P) to a 1-L volumetric flask, add 50 mL of HClO (1 + 5),
flask.
dilute to volume, and mix.
27.2 Reagent Blank—Proceed as directed in 26.2.
25.6 Phosphorus Standard Solution C (1 mL = 0.10 mg
27.3 Color Development—Proceed as directed in 26.3.
P)—Using a pipet, transfer 50 mL of Solution A (1 mL = 1.0
mg P) to a 500-mL volumetric flask, add 50 mL of HClO (1
27.4 Reference Solution—Water.
+ 5), dilute to volume, and mix.
27.5 Spectrophotometry:
25.7 Sodium Sulfite Solution (100 g/L)—Dissolve 100 g of
27.5.1 Multiple-Cell Spectrophotometer—Measure the re-
sodium sulfite (Na SO ) in water, dilute to 1 L, and mix.
agent blank (which includes the cell correction) versus the
2 3
reference solution (27.4) using absorption cells with a 1-cm
26. Preparation of Calibration Curve for Concentrations
light path and a light band centered at 650 nm. Using the test
from 0.005 mg/100 mL to 0.05 mg/100 mL cell, take the spectrophotometric absorbance readings of the
calibration solutions versus the reference solution.
26.1 Calibration Solutions—Using pipets, transfer (5, 10,
27.5.2 Single-Cell Spectrophotometer—Transfer a suitable
15, 25, and 50) mL of Phosphorus Standard Solution B (1 mL
portion of the reference solution (27.4) to an absorption cell
= 0.01 mg P) to 100-mL volumetric flasks. Add 20 mL of
with a 1-cm light path and adjust the spectrophotometer to the
HClO , dilute to volume, and mix. Using a pipet, transfer 10
initial setting using a light band (no change) centered at 650
mL of each solution to a 100-mL borosilicate glass volumetric
nm. While maintaining this adjustment, take the spectrophoto-
flask. Proceed as directed in 26.3.
metric absorbance readings of the reagent blank solution and of
26.2 Reagent Blank—Transfer 12 mL of HClO (1 + 5) to a
4 the calibration solutions.
100-mL borosilicate glass volumetric flask.
27.6 Calibration Curve—Follow the instrument manufac-
26.3 Color Development:
turer’s instructions for generating the calibration curve. Plot
26.3.1 Add 15 mL of Na SO solution, boil gently for 30 s, the net spectrophotometric absorbance readings of the calibra-
2 3
and add 50 mL of ammonium molybdate-hydrazine sulfate
tion solutions against milligrams of phosphorus per 100 mL of
solution that has been prepared within the hour. solution.
26.3.2 Heat the solutions at not less than 90 °C for 20 min,
quickly cool, dilute to volume, and mix. 28. Procedure
28.1 Test Solution:
NOTE 4—Immersing the flasks in a boiling water bath is the preferred
28.1.1 Transfer a 1.0-g sample, weighed to the nearest 0.5
means of heating them for complete color development.
mg, to a 250-mL Erlenmeyer flask.
26.4 Reference Solution—Water.
28.1.2 Add 15 mL of a freshly prepared mixture of 1
26.5 Spectrophotometry:
volume of HNO and 3 volumes of HCl, slowly and in small
26.5.1 Multiple-Cell Spectrophotometer—Measure the re-
portions. When the reaction has ceased, add 10 mL of HClO
agent blank (which includes the cell correction) versus the
and evaporate to fumes. Remove the flask immediately to
reference solution (26.4) using absorption cells with a 1-cm
avoid undue loss of HClO , cool, and add 20 mL of HBr (1 +
light path and using a light band centered at 825 nm. Using the
4). Evaporate the solution to copious whit fumes and then,
test cell, take the spectrophotometric absorbance readings of
without delay, fume strongly enough to cause the white fumes
the calibration solutions versus the reference solution.
to clear the neck of the flask, and continue at this rate for 1 min.
26.5.2 Single-Cell Spectrophotometer—Transfer a suitable
28.1.3 Cool the solution, add 60 mL of HClO (1 + 5), and
portion of the reference solution (26.4) to an absorption cell
swirl to dissolve the salts. Transfer to a 100-mL volumetric
with a 1-cm light path and adjust the spectrophotometer to the
flask, cool, dilute to volume, and mix. Allow insoluble matter
initial setting using a light band centered at 825 nm. While
to settle or dry filter the solution. Using a pipet, transfer 10-mL
maintaining this adjustment, take the spectrophotometric ab-
portions to two 100-mL borosilicate glass volumetric flasks;
sorbance readings of the reagent blank solution and of the
treat one as directed in 28.3 and the other as directed in 28.4.2.
calibration solutions.
28.2 Reagent Blank Solution—Carry a reagent blank
26.6 Calibration Curve—Follow the instrument manufac- through the entire procedure using the same amount of all
turer’s instructions for generating the calibration curve. Plot reagents with the sample omitted.
E350 − 23
28.3 Color Development—Proceed with one of the 10-mL SILICON BY THE GRAVIMETRIC METHOD
portions obtained in 28.1.3, as directed in 26.3.
46. Scope
28.4 Reference Solutions:
46.1 This test method covers the determination of silicon
28.4.1 Water—Use this as the reference solution for the
from 0.05 % to 3.5 %.
reagent blank solution.
28.4.2 Background Color Reference Solution—Add 15 mL
46.2 The upper limit of the scope has been set at 3.5 %
of Na SO solution to the second 10-mL portion obtained in
2 3
because test materials containing higher silicon contents were
28.1.3. Boil gently for 30 s, add 50 mL of H SO (3 + 37), cool,
2 4
unavailable for testing as directed in Practice E173. However,
dilute to volume, and mix. Use this as the reference solution for
recognizing that the chemical principles used in this test
the test solution.
method are capable of handling higher compositions, the test
method should be expandable to at least 5 %. Users of this test
28.5 Spectrophotometry—Take the spectrophotometric ab-
method are cautioned that its use above 3.5 % is not supported
sorbance readings of the reagent blank solution and of the test
by interlaboratory testing.
solution (using the respective reference solutions) as directed
in 26.5 or 27.5 depending upon the estimated level of phos-
47. Summary of Test Method
phorus in the sample.
47.1 After dissolution of the sample, silicic acid is dehy-
29. Calculation
drated by fuming with H SO or HClO . The solution is
2 4 4
29.1 Convert the net spectrophotometric absorbance reading filtered, and the impure silica is ignited and weighed. The silica
of the test solution and of the reagent blank solution to is then volatilized with HF. The residue is ignited and weighed;
milligrams of phosphorus by means of the appropriate calibra- the loss in mass represents silica.
tion curve. Calculate the percent of phosphorus as follows:
48. Interferences
Phosphorus, % 5 A 2 B / C × 10 (2)
~ ! ~ !
48.1 The elements normally present do not interfere if their
where:
compositions are under the maximum limits shown in 1.1.
A = phosphorus found in 100 mL of the final test solution,
mg,
49. Reagents
B = phosphorus found in 100 mL of the final reagent blank
49.1 The analyst should ensure, by analyzing blanks and
solution, mg, and
other checks, that possible silicon contamination of reagents
C = sample represented in 100 mL of the final test solution,
will not significantly bias the results.
g.
49.2 HClO :
30. Precision and Bias
49.2.1 Select a lot of HClO that contains not more than
0.0002 % silicon for the analysis of samples containing silicon
30.1 Precision—Nine laboratories cooperated in testing this
in the range from 0.02 % to 0.10 % and not more than 0.0004
test method and obtained the data summarized in Table 2.
% silicon for samples containing more than 0.10 % by
30.2 Bias—The accuracy of this test method has been
determining duplicate values for silicon as directed in 49.2.2 –
deemed satisfactory based upon the data for the certified
49.2.6.
reference materials in Table 2. Users are encouraged to use
49.2.2 Transfer 15 mL of HClO (Note 5) to each of two
these or similar reference materials to verify that the test
400-mL beakers. To one of the beakers transfer an additional
method is performing accurately in their laboratories.
50 mL of HClO . Using a pipet, transfer 20 mL of Na SiO
4 2 3
solution (1 mL = 1.00 mg Si) to each of the beakers. Evaporate
the solutions to fumes and heat for 15 min to 20 min at such a
SULFUR BY THE GRAVIMETRIC METHOD
rate that HClO refluxes on the sides of the beakers. Cool
(This test method, which consisted of Sections 31 through 36
sufficiently, and add 100 mL of water (40 °C to 50 °C).
of this standard, was discontinued in 1988.)
NOTE 5—The 15-mL addition of HClO can be from the same lot as the
one to be tested. Once a lot has been established as having less than 0.0002
SULFUR BY THE COMBUSTION-IODATE
% silicon, it should preferably be used for the 15-mL addition in all
TITRATION METHOD subsequent tests of other lots of acid.
(This test method, which consisted of Sections 37 through 45 49.2.3 Add paper pulp and filter immediately, using low-ash
of this standard, was discontinued in 2017.) 11-cm medium-porosity filter papers. Transfer the precipitates
TABLE 2 Statistical Information—Phosphorus—Molybdenum Blue Spectrophotometric Method
Phosphorus Found, Repeatability Reproducibility
Test Material
% (R , E173) (R , E173)
1 2
1. Ingot iron (NIST 55e, 0.003 P) 0.002 0.001 0.002
2. Carbon steel (NIST 12g, 0.014 P) 0.014 0.002 0.003
3. Carbon steel (NIST 10g, 0.086 P) 0.084 0.006 0.009
E350 − 23
to the papers, and scrub the beakers thoroughly with a 50.3.1 Add amounts of HCl or HNO , or mixtures and
rubber-tipped rod. Wash the papers and precipitates alternately dilutions of these acids, which are sufficient to dissolve the
with 3 mL to 5 mL portions of hot HCl (1 + 19) and hot water, sample, and cover. Heat until dissolution is complete. Add
for a total of 6 times. Finally wash the papers twice with H SO HNO to provide a total of 35 mL to 40 mL, followed by
2 4 3
(1 + 49). Transfer the papers to platinum crucibles.
HClO as specified in the table in 50.1. Remove and rinse the
49.2.4 Dry the papers and heat at 600 °C until the carbon is cover glass; substitute a ribbed cover glass.
removed. Finally ignite at 1100 °C to 1150 °C to constant mass
50.3.2 Evaporate the solution to fumes and heat for 15 min
(at least 30 min). Cool in a desiccator and weigh.
to 20 min at such a rate that the HClO refluxes on the sides of
49.2.5 Add enough H SO (1 + 1) to moisten the SiO , and
2 4 2
the container. Cool sufficiently and add 100 mL of water (40 °C
add 3 mL to 5 mL of HF. Evaporate to dryness and then heat
to 50 °C). Stir to dissolve the salts and heat to boiling. If the
at a gradually increasing rate until H SO is removed. Ignite
2 4
sample solution contains more than 100 mg of chromium, add,
for 15 min at 1100 °C to 1150 °C, cool in a desiccator, and
while stirring, 1 mL of tartaric acid solution for each 25 mg of
weigh.
chromium.
49.2.6 Calculate the percent of silicon as follows:
50.4 Add paper pulp and filter immediately, on a low-ash
Silicon, % 5 @~A 2 B! 2 ~C 2 D!# × 0.4674/E × 100 (3)
11-cm medium-porosity filter paper. Collect the filtrate in a
600-mL beaker. Transfer the precipitate to the paper, and scrub
where:
the container thoroughly with a rubber-tipped rod. Wash the
A = initial mass of crucible plus impure SiO when 65 mL of
paper and precipitate alternately with 3 mL to 5 mL portions of
HClO was taken, g,
hot HCl (1 + 19) and hot water until iron salts are removed but
B = final mass of crucible plus impurities when 65 mL of
for not more than a total of ten washings. If 50.3 was followed,
HClO was taken, g,
wash the paper twice more with H SO (1 + 49), but do not
C = initial mass of crucible plus impure SiO when 15 mL of
2 4
collect these washings in the filtrate; discard the washings.
HClO was taken, g,
D = final mass of crucible plus impurities when 15 mL of Transfer the paper to a platinum crucible and reserve.
HClO was taken, g, and
50.5 Add 15 mL of HNO to the filtrate, stir, and evaporate
E = nominal mass (80 g) of 50 mL of HClO .
as directed in either 50.2 or 50.3, depending upon the dehy-
49.3 Sodium Silicate Solution—Transfer 11.0 g of sodium
drating acid used. Filter immediately, using a low-ash, 9-cm-
silicate (Na SiO ·9H O) to a 400-mL beaker. Add 150 mL of
2 3 2 100-porosity filter paper, and wash as directed in 50.4.
water and dissolve the salt. Filter through a medium paper,
50.6 Transfer the paper and precipitate to the reserved
collecting the filtrate in a 1-L volumetric flask, dilute to
platinum crucible. Dry the papers and then heat the crucible at
volume, and mix. Store in a polyethylene bottle. Use this
600 °C until the carbon is removed. Finally ignite at 1100 °C
solution to determine the suitability of the HClO .
to 1150 °C to constant mass (at least 30 min). Cool in a
49.4 Tartaric Acid Solution (20.6 g/L)—Dissolve 20.6 g of
desiccator and weigh.
tartaric acid (C H O ) in water, dilute to 1 L, and filter.
4 6 6
50.7 Add enough H SO (1 + 1) to moisten the impure
2 4
50. Procedure
SiO , and add 3 mL to 5 mL of HF. Evaporate to dryness and
then heat at a gradually increasing rate until H SO is removed.
50.1 Select and weigh a sample as follows:
2 4
Ignite at 1100 °C to 1150 °C for 15 min, cool in a desiccator,
Tolerance in Dehydrating Acid, mL
Sample Sample H SO and weigh.
2 4
Silicon, % mass, g mass, mg (1 + 4) HClO
0.05 to 0.10 5.0 5 150 75
51. Calculation
0.10 to 1.0 4.0 4 100 60
1.0 to 2.0 3.0 3 100 50
51.1 Calculate the percent of silicon as follows:
2.0 to 5.0 2.0 2 100 40
Transfer the sample to a 400-mL beaker or a 300-mL Silicon, % 5 A 2 B × 0.4674 /C × 100 (4)
@~~ ! ! #
porcelain casserole. Proceed as directed in 50.2 or 50.3.
where:
50.2 H SO Dehydration:
2 4
A = initial mass of crucible and impure SiO , g,
50.2.1 Add amounts of HCl or HNO , or mixtures and
B = final mass of crucible and residue, g, and
dilutions of these acids, that are sufficient to dissolve the
C = sample used, g.
sample; and then add the H SO (1 + 4) as specified in 50.1,
2 4
and cover. Heat until dissolution is complete. Remove and
52. Precision and Bias
rinse the cover glass; substitute a ribbed cover glass.
52.1 Precision—Eleven laboratories cooperated in testing
50.2.2 Evaporate until salts begin to separate; at this point
this test method and obtained the data summarized in Table 3.
evaporate the solution rapidly to the first appearance of fumes
and fume strongly for 2 min to 3 min. Cool sufficiently, and add
52.2 Bias—The accuracy of this test method has been
100 mL of water (40 °C to 50 °C). Stir to dissolve the salts and
deemed satisfactory based upon the data for the certified
heat, if necessary, but do not boil. Proceed immediately as
reference materials in Table 3. Users are encouraged to use
directed in 50.4.
these or similar reference materials to verify that the test
50.3 HClO Dehydration: method is performing accurately in their laboratories.
E350 − 23
TABLE 3 Statistical Information—Silicon—Gravimetric Method
Silicon Found, Repeatability Reproducibility
Test Material
% (R , E173) (R , E173)
1 2
HCIO Dehydration
1. Carbon steel 0.053 0.015 0.036
2. Carbon steel (NIST 14d, 0.126 Si) 0.127 0.011 0.011
3. Carbon steel (NIST 19g, 0.186 Si) 0.186 0.011 0.010
4. Carbon steel (NIST 12g, 0.187 Si) 0.187 0.011 0.012
5. Low-alloy steel (NIST 32e, 0.278 Si) 0.280 0.011 0.012
6. Carbon steel (NIST 20f, 0.299 Si) 0.300 0.012 0.016
7. Electrical steel (NIST 125a, 3.32 Si) 3.33 0.07 0.07
H SO Dehydration
2 4
1. Carbon steel 0.046 0.009 0.013
2. Carbon steel (NIST 14d, 0.126 Si) 0.128 0.016 0.016
3. Carbon steel (NIST 19g, 0.186 Si) 0.186 0.014 0.019
4. Carbon steel (NIST 12g, 0.187 Si) 0.188 0.007 0.016
5. Low-alloy steel (NIST 32e, 0.278 Si) 0.282 0.015 0.024
6. Carbon steel (NIST 20f, 0.299 Si) 0.302 0.015 0.015
7. Electrical steel (NIST 125a, 3.32 Si) 3.33 0.05 0.05
COBALT BY THE NITROSO-R-SALT cobalt sulfate (CoSO ) that has been heated at 550 °C for 1 h
SPECTROPHOTOMETRIC METHOD to the weighing bottle. Dry the bottle and contents at 130 °C for
1 h, cool in a desiccator, stopper the bottle, and weigh. The
53. Scope
difference in mass is the exact amount of CoSO taken.
Transfer the weighed CoSO to a 400-mL beaker, rinse the
53.1 This test method covers the determination of cobalt
from 0.01 % to 0.30 %. weighing bottle with water, and transfer the rinsings to the
beaker. Add 150 mL of water and 10 mL of HCl, and heat to
54. Summary of Test Method
dissolve the salts. Cool, transfer to a 500-mL volumetric flask,
dilute to volume, and mix. By means of a pipet, transfer a
54.1 The sample solution is treated with zinc oxide to
50-mL aliquot of this solution to a 500-mL volumetric flask,
remove iron, chromium, and vanadium. Nitroso-R-salt solution
dilute to volume, and mix. The exact concentration (in milli-
is added to a portion of the filtrate which has been buffered
grams of cobalt per millilitre) of the final solution is the exact
with sodium acetate to produce an orange-colored complex
mass of CoSO taken multiplied by 0.076046.
with cobalt. The addition of nitric acid stabilizes the cobalt
complex and also destroys certain interfering complexes.
58.2 Nitroso-R Salt Solution (7.5 g/L)—Dissolve 1.50 g of
Spectrophotometric absorbance measurement is made at 520
1-nitroso-2-naphthol-3,6-disulfonic acid disodium salt
nm.
(nitroso-R salt) in about 150 mL of water, filter, and dilute to
200 mL. This solution is stable for 1 week.
55. Concentration Range
58.3 Sodium Acetate Solution (500 g/L)—Dissolve 500 g of
55.1 The recommended concentration range is from 0.005
sodium acetate trihydrate (CH COONa·3H O) in about 600
3 2
mg to 0.15 mg of cobalt per 50 mL of solution, using a 1-cm
mL of water, filter, and dilute to 1 L.
cell.
NOTE 6—This test method has been written for cells having a 1-cm light 58.4 Zinc Oxide Suspension (166 g/L)—Add 10 g of finely
path. Cells having other dimensions may be used, provided suitable
divided zinc oxide (ZnO) to 60 mL of water and shake
adjustments can be made in the amounts of sample and reagents used.
thoroughly. Prepare fresh daily as needed.
56. Stability of Color
59. Preparation of Calibration Curve
56.1 The color is stable for at least 3 h.
59.1 Calibration Solutions—Using pipets, transfer (2, 5, 10,
15, 20, and 25) mL of cobalt standard solution (1 mL = 0.06 mg
57. Interferences
Co) to six 100-mL volumetric flasks, dilute to volume, and
57.1 Nickel, manganese, and copper form complexes with
mix. Using a pipet, transfer 10 mL of each solution to a 50-mL
nitroso-R-salt that deplete the reagent and inhibit the formation
borosilicate glass volumetric flask. Proceed as directed in 59.3.
of the colored cobalt complex. A sufficient amount of nitroso-
59.2 Reference Solution—Transfer 10 mL of water to a
R-
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E350 − 18 E350 − 23
Standard Test Methods for
Chemical Analysis of Carbon Steel, Low-Alloy Steel, Silicon
Electrical Steel, Ingot Iron, and Wrought Iron
This standard is issued under the fixed designation E350; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 These test methods cover the chemical analysis of carbon steels, low-alloy steels, silicon electrical steels, ingot iron, and
wrought iron having chemical compositions within the following limits:
Element Composition Range, %
Aluminum 0.001 to 1.50
Antimony 0.002 to 0.03
Arsenic 0.0005 to 0.10
Bismuth 0.005 to 0.50
Boron 0.0005 to 0.02
Calcium 0.0005 to 0.01
Cerium 0.005 to 0.50
Chromium 0.005 to 3.99
Cobalt 0.01 to 0.30
Columbium (Niobium) 0.002 to 0.20
Copper 0.005 to 1.50
Lanthanum 0.001 to 0.30
Lead 0.001 to 0.50
Manganese 0.01 to 2.50
Molybdenum 0.002 to 1.50
Nickel 0.005 to 5.00
Nitrogen 0.0005 to 0.04
Oxygen 0.0001 to 0.03
Phosphorus 0.001 to 0.25
Selenium 0.001 to 0.50
Silicon 0.001 to 5.00
Sulfur 0.001 to 0.60
Tin 0.002 to 0.10
Titanium 0.002 to 0.60
Tungsten 0.005 to 0.10
Vanadium 0.005 to 0.50
Zirconium 0.005 to 0.15
1.2 The test methods in this standard are contained in the sections indicated as follows:
Sections
Aluminum, Total, by the 8-Quinolinol Gravimetric 124–131
Method (0.20 % to 1.5 %)
These test methods are under the jurisdiction of ASTM Committee E01 on Analytical Chemistry for Metals, Ores, and Related Materials and are the direct responsibility
of Subcommittee E01.01 on Iron, Steel, and Ferroalloys.
Current edition approved March 15, 2018Nov. 15, 2023. Published May 2018December 2023. Originally approved in 1968. Last previous edition approved in 20122018
as E350 – 12.E350 – 18. DOI: 10.1520/E0350-18.10.1520/E0350-23.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E350 − 23
Sections
Aluminum, Total, by the 8-Quinolinol 76–86
Spectrophotometric Method
(0.003 % to 0.20 %)
Aluminum, Total or Acid-Soluble, by the Atomic 308–317
Absorption Spectrometry Method
(0.005 % to 0.20 %)
Antimony by the Brilliant Green Spectrophotometric 142–151
Method (0.0002 % to 0.030 %)
Bismuth by the Atomic Absorption Spectrometry 298–307
Method (0.02 % to 0.25 %)
Boron by the Distillation-Curcumin 208–219
Spectrophotometric Method
(0.0003 % to 0.006 %)
Calcium by the Direct-Current Plasma Atomic 289–297
Emission Spectrometry Method
(0.0005 % to 0.010 %)
Carbon, Total, by the Combustion Gravimetric Method
(0.05 % to 1.80 %)—Discontinued 1995
Cerium and Lanthanum by the Direct Current Plasma 249–257
Atomic Emission Spectrometry Method
(0.003 % to 0.50 % Cerium, 0.001 % to 0.30 %
Lanthanum)
Chromium by the Atomic Absorption Spectrometry 220–229
Method (0.006 % to 1.00 %)
Chromium by the Peroxydisulfate Oxidation-Titration 230–238
Method (0.05 % to 3.99 %)
Cobalt by the Nitroso-R Salt Spectrophotometric 53–62
Method (0.01 % to 0.30 %)
Copper by the Sulfide Precipitation-Iodometric 87–94
Titration Method (Discontinued 1989)
Copper by the Atomic Absorption Spectrometry 279–288
Method (0.004 % to 0.5 %)
Copper by the Neocuproine Spectrophotometric 114–123
Method (0.005 % to 1.50 %)
Lead by the Ion-Exchange—Atomic Absorption 132–141
Spectrometry Method
(0.001 % to 0.50 %)
Manganese by the Atomic Absorption Spectrometry 269–278
Method (0.005 % to 2.0 %)
Manganese by the Metaperiodate Spectrophotometric 9–18
Method (0.01 % to 2.5 %)
Manganese by the Peroxydisulfate-Arsenite Titrimetric 164–171
Method (0.10 % to 2.50 %)
Molybdenum by the Thiocyanate Spectrophotometric 152–163
Method (0.01 % to 1.50 %)
Nickel by the Atomic Absorption Spectrometry 318–327
Method (0.003 % to 0.5 %)
Nickel by the Dimethylglyoxime Gravimetric 180–187
Method (0.1 % to 5.00 %)
Nickel by the Ion-Exchange-Atomic-Absorption 188–197
Spectrometry Method
(0.005 % to 1.00 %)
Nitrogen by the Distillation-Spectrophotometric 63–75
Method (Discontinued 1988)
Phosphorus by the Alkalimetric Method 172–179
(0.02 % to 0.25 %)
Phosphorus by the Molybdenum Blue 19–30
Spectrophotometric Method
(0.003 % to 0.09 %)
Silicon by the Molybdenum Blue Spectrophotometric 103–113
Method (0.01 % to 0.06 %)
Silicon by the Gravimetric Titration 46–52
Method (0.05 % to 3.5 %)
Sulfur by the Gravimetric Method 31–36
(Discontinued 1988)
Sulfur by the Combustion-Iodate Titration Method 37–45
(0.005 % to 0.3 %) (Discontinued 2017)
Tin by the Sulfide Precipitation-Iodometric Titration 95–102
Method (0.01 % to 0.1 %)
Tin by the Solvent Extraction-Atomic Absorption 198–207
Spectrometry Method
(0.002 % to 0.10 %)
Titanium by the Diantipyrylmethane 258–268
Spectrophotometric Method
(0.025 % to 0.30 %)
E350 − 23
Sections
Vanadium by the Atomic Absorption Spectrometry 239–248
Method (0.006 % to 0.15 %)
1.3 Test methods for the determination of several elements not included in this standard can be found in Test Methods E1019.
1.4 Some of the composition ranges given in 1.1 are too broad to be covered by a single test method and therefore this standard
contains multiple test methods for some elements. The user must select the proper test method by matching the information given
in the Scope and Interference sections of each test method with the composition of the alloy to be analyzed.
1.5 The values stated in SI units are to be regarded as standard. In some cases, exceptions allowed in IEEE/ASTM SI 10 are also
used.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use. Specific hazards statements are given in Section 6 and in special “Warning” paragraphs
throughout these test methods.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1193 Specification for Reagent Water
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E50 Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
E60 Practice for Analysis of Metals, Ores, and Related Materials by Spectrophotometry
E135 Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
E173 Practice for Conducting Interlaboratory Studies of Methods for Chemical Analysis of Metals (Withdrawn 1997)
E351 Test Methods for Chemical Analysis of Cast Iron—All Types
E352 Test Methods for Chemical Analysis of Tool Steels and Other Similar Medium- and High-Alloy Steels
E353 Test Methods for Chemical Analysis of Stainless, Heat-Resisting, Maraging, and Other Similar Chromium-Nickel-Iron
Alloys
E354 Test Methods for Chemical Analysis of High-Temperature, Electrical, Magnetic, and Other Similar Iron, Nickel, and
Cobalt Alloys
E882 Guide for Accountability and Quality Control in the Chemical Analysis Laboratory
E1019 Test Methods for Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt Alloys by
Various Combustion and Inert Gas Fusion Techniques
E1024 Guide for Chemical Analysis of Metals and Metal Bearing Ores by Flame Atomic Absorption Spectrophotometry
(Withdrawn 2004)
E1601 Practice for Conducting an Interlaboratory Study to Evaluate the Performance of an Analytical Method
E1806 Practice for Sampling Steel and Iron for Determination of Chemical Composition
IEEE/ASTM SI 10 Standard for Use of the International System of Units (SI): The Modern Metric System
2.2 ISO Standard:
ISO 5725 Precision of Test Methods—Determination of Repeatability and Reproducibility for Inter-Laboratory Tests
3. Terminology
3.1 For definitions of terms used in these test methods, refer to Terminology E135.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
E350 − 23
4. Significance and Use
4.1 These test methods for the chemical analysis of metals and alloys are primarily intended as referee methods to test such
materials for compliance with compositional specifications, particularly those under the jurisdiction of ASTM Committees A01 on
Steel, Stainless Steel, and Related Alloys and A04 on Iron Castings. It is assumed that all who use these test methods will be trained
analysts capable of performing common laboratory procedures skillfully and safely. It is expected that work will be performed in
a properly equipped laboratory under appropriate quality control practices such as those described in Guide E882.
5. Apparatus, Reagents, and Instrumental Practices
5.1 Apparatus—Specialized apparatus requirements are listed in the “Apparatus” Section in each test method.
5.1.1 In the methods specifying spectrophotometric testing, the cells utilized to contain the reference material solutions and the
sample solutions in spectrophotometers are referred to as “absorption cells.” Please note that the radiant energy passed through the
cells can be measured as absorbance or transmittance. These methods refer to absorbance measurements. Refer to Practice E60 for
details.
5.2 Reagents:
5.2.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, all reagents used in these
test methods shall conform to the reagent grade specifications of the American Chemical Society.Committee on Analytical
Reagents of the American Chemical Society where such specifications are available. Other chemicals may be used, provided it
is first ascertained that they are of sufficiently high purity to permit their use without adversely affecting the expected performance
of the determination, as indicated in the Precision and Bias section.
5.2.2 Purity of Water—Unless otherwise indicated, references to water shall mean reagent water as conforming to Type I or Type
II of Specification D1193. Type III or IV may be used if they effect no measurable change in the blank or sample.
6. Hazards
6.1 For precautions to be observed in the use of certain reagents and equipment in these test methods, refer to Practices E50.
7. Sampling
7.1 For procedures to sample the material, refer to Practice E1806.
8. Interlaboratory Studies and Rounding Calculated Values
8.1 These test methods have been evaluated using Practice E173 or ISO 5725.
8.1.1 Practice E173 has been replaced by Practice E1601. The reproducibility, R , of Practice E173 corresponds to the
reproducibility index, R, of Practice E1601. The repeatability, R , of Practice E173 corresponds to the repeatability index, r, of
Practice E1601.
8.2 Rounding of test results obtained using these test methods shall be performed as directed in Practice E29, Rounding Method,
unless an alternative rounding method is specified by the customer or applicable material specification.
MANGANESE BY THE METAPERIODATE SPECTROPHOTOMETRIC METHOD
9. Scope
9.1 This test method covers the determination of manganese from 0.01 % to 2.5 %.
Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC, www.chemistry.org.www.acs.org. For suggestions on the
testing of reagents not listed by the American Chemical Society, see the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC),
Rockville, MD, http://www.usp.org.
E350 − 23
10. Summary of Test Method
10.1 Manganous ions are oxidized to permanganate ions by reaction with metaperiodate ions. Solutions of the samples are fumed
with HClO so that the effect of metaperiodate ion is limited to the oxidation of manganese. Spectrophotometric absorbance
measurement is made at 545 nm.
11. Concentration Range
11.1 The recommended concentration range is from 0.15 mg to 0.8 mg of manganese per 50 mL of solution, using a 1-cm cell
(Note 1) and a spectrophotometer with a band width of 10 nm or less.
NOTE 1—This test method has been written for cells having a 1-cm light path and a “narrow-band” instrument. The concentration range depends upon
band width and spectral region used as well as cell optical path length. Cells having other dimensions may be used, provided suitable adjustments can
be made in the amounts of sample and reagents used.
12. Stability of Color
12.1 The color is stable for at least 24 h.
13. Interferences
13.1 The elements ordinarily present do not interfere. HClO treatment, which is used in the procedure, yields solutions which can
be highly colored due to the presence of Cr (VI) ions. Although these ions and other colored ions in the sample solution undergo
no further change in color quality upon treatment with metaperiodate ion, the following precautions must be observed when filter
spectrophotometers are used: Select a filter with maximum transmittance between 545 nm and 565 nm. The filter must transmit
not more than 5 % of its maximum at a wavelength shorter than 530 nm. The band width of the filter should be less than 30 nm
when measured at 50 % of its maximum transmittance. Similar restrictions apply with respect to the wavelength region employed
when other “wide-band” instruments are used.
13.2 The spectral transmittance curve of permanganate ions exhibits two useful minima, one at approximately 526 nm, and the
other at 545 nm. The latter is recommended when a “narrow-band” spectrophotometer is used.
14. Reagents
14.1 Manganese, Standard Solution (1 mL = 0.032 mg Mn)—Transfer the equivalent of 0.4000 g of assayed, high-purity
manganese (purity: 99.99 % minimum), to a 500-mL volumetric flask and dissolve in 20 mL of HNO by heating. Cool, dilute to
volume, and mix. Using a pipet, transfer 20 mL to a 500-mL volumetric flask, dilute to volume, and mix.
14.2 Nitric-Phosphoric Acid Mixture—Cautiously, while stirring, add 100 mL of HNO and 400 mL of H PO to 400 mL of water.
3 3 4
Cool, dilute to 1 L, and mix. Prepare fresh as needed.
14.3 Potassium Metaperiodate Solution (7.5 g/L)—Dissolve 7.5 g of potassium metaperiodate (KIO ) in 200 mL of hot HNO (1
4 3
+ 1), add 400 mL of H PO , cool, dilute to 1 L, and mix.
3 4
14.4 Water, Pretreated with Metaperiodate—Add 20 mL of KIO solution to 1 L of water, mix, heat at not less than 90 °C for 20
min to 30 min, and cool. Use this water to dilute solutions to volume that have been treated with KIO solution to oxidize
manganese, and thus avoid reduction of permanganate ions by any reducing agents in the untreated water. Caution—Avoid the
use of this water for other purposes.
15. Preparation of Calibration Curve
15.1 Calibration Solutions—Using pipets, transfer (5, 10, 15, 20, and 25) mL of manganese standard solution (1 mL = 0.032 mg
Mn) to 50-mL borosilicate glass volumetric flasks, and, if necessary, dilute to approximately 25 mL. Proceed as directed in 15.3.
15.2 Reference Solution—Transfer approximately 25 mL of water to a 50-mL borosilicate glass volumetric flask. Proceed as
directed in 15.3.
E350 − 23
15.3 Color Development—Add 10 mL of KIO solution, and heat the solutions at not less than 90 °C for 20 min to 30 min (Note
2). Cool, dilute to volume with pretreated water, and mix.
NOTE 2—Immersing the flasks in a boiling water bath is a preferred means of heating them for the specified period to ensure complete color development.
15.4 Spectrophotometry:
15.4.1 Multiple-Cell Spectrophotometer—Measure the cell correction using the Reference Solution (15.2) in absorption cells with
a 1-cm light path and using a light band centered at 545 nm. Using the test cell, take the spectrophotometric absorbance readings
of the calibration solutions versus the reference solution (15.2).
15.4.2 Single-Cell Spectrophotometer—Transfer a suitable portion of the reference solution (15.2) to an absorption cell with a
1-cm light path and adjust the spectrophotometer to the initial setting, using a light band centered at 545 nm. While maintaining
this adjustment, take the spectrophotometric absorbance readings of the calibration solutions.
15.5 Calibration Curve—Follow the instrument manufacturer’s instructions for generating the calibration curve. Plot the net
spectrophotometric absorbance readings of the calibration solutions against milligrams of manganese per 50 mL of solution.
16. Procedure
16.1 Test Solution:
16.1.1 Select and weigh a sample as follows:
Sample Tolerance in Aliquot
Manganese, Mass, Sample Mass, Dilution, Volume,
% g mg mL mL
0.01 to 0.5 0.80 0.5 100 20
0.45 to 1.0 0.35 0.3 100 20
0.85 to 2.0 0.80 0.5 500 20
1.95 to 2.5 0.80 0.5 500 10
Transfer the sample to a 100-mL or 500-mL borosilicate glass volumetric flask as directed in the above table or to a 300-mL
Erlenmeyer flask if HF is to be used in sample dissolution.
16.1.2 To dissolve samples that do not require HF, add 8 mL to 10 mL of HCl (1 + 1), and heat. Add HNO as needed to hasten
dissolution, and then add 3 mL to 4 mL in excess. When dissolution is complete, cool, then add 10 mL of HClO ; evaporate to
fumes to oxidize chromium, if present, and to expel HCl. Continue fuming until salts begin to separate. Cool, add 50 mL of water,
and digest if necessary to dissolve the salts. Cool and transfer the solution to either a 100-mL or 500-mL volumetric flask as
indicated in 16.1.1. Proceed to 16.1.4.
16.1.3 For samples whose dissolution is hastened by HF, treat them in a 300-mL Erlenmeyer flask by adding 8 mL to 10 mL of
HCl (1 + 1), and heating. Add HNO and a few drops of HF as needed to hasten dissolution, and then add 3 mL to 4 mL of HNO .
3 3
When dissolution is complete, cool, then add 10 mL of HClO , evaporate to fumes to oxidize chromium, if present, and to expel
HCl. Continue fuming until salts begin to separate. Cool, add 50 mL of water, digest if necessary to dissolve the salts, cool, and
transfer the solution to either a 100-mL or 500-mL volumetric flask as indicated in 16.1.1.
16.1.4 Cool the solution to room temperature, dilute to volume, and mix. Allow insoluble matter to settle, or dry-filter through a
coarse paper and discard the first 15 mL to 20 mL of the filtrate, before taking aliquots.
16.1.5 Using a pipet, transfer 10 mL to 20 mL aliquots, as directed in 16.1.1, to two 50-mL borosilicate glass volumetric flasks.
Treat one portion as directed in 16.3. Treat the other portion as directed in 16.4.1.
16.2 Reagent Blank Solution—Carry a reagent blank through the entire procedure using the same amounts of all reagents with the
sample omitted.
16.3 Color Development—Proceed as directed in 15.3.
E350 − 23
16.4 Reference Solutions:
16.4.1 Background Color Solution—To one of the sample aliquots in a 50-mL volumetric flask, add 10 mL of nitric-phosphoric
acid mixture, and heat the solution at not less than 90 °C for 20 min to 30 min (Note 2 in 15.3). Cool, dilute to volume (with
untreated water), and mix.
16.4.2 Reagent Blank Reference Solution—Transfer the reagent blank solution (16.2) to the same size volumetric flask as used for
the test solutions and transfer the same size aliquots as used for the test solutions to two 50-mL volumetric flasks. Treat one portion
as directed in 16.3 and use as reference solution for test samples. Treat the other as directed in 16.4.1 and use as reference solution
for Background Color Solutions.
16.5 Spectrophotometry—Establish the cell corrections with the reagent blank reference solution to be used as a reference solution
for background color solutions. Take the spectrophotometric absorbance readings of the Background Color Solutions and the test
solutions versus the respective Reagent Blank Reference Solutions as directed in15.4.
17. Calculation
17.1 Convert the net spectrophotometric absorbance reading of the test solution and of the background color solution to milligrams
of manganese by means of the calibration curve. Calculate the percent of manganese as follows:
Manganese, %5 A 2 B / C ×10 (1)
~ ! ~ !
where:
A = manganese found in 50 mL of the final test solution, mg,
B = apparent manganese found in 50 mL of the final background color solution, mg, and
C = sample represented in 50 mL of the final test solution, g.
18. Precision and Bias
18.1 Precision—Nine laboratories cooperated in testing this test method and obtained the data summarized in Table 1. Although
a sample covered by this test method with manganese composition of approximately 2.5 % was not available, the precision data
for this composition should be similar to those obtained for Material 7.
18.2 Bias—The accuracy of this test method has been deemed satisfactory based upon the data for the certified reference materials
in Table 1. Users are encouraged to use these or similar reference materials to verify that the test method is performing accurately
in their laboratories.
PHOSPHORUS BY THE MOLYBDENUM BLUE SPECTROPHOTOMETRIC METHOD
19. Scope
19.1 This test method covers the determination of phosphorus from 0.003 % to 0.09 %.
TABLE 1 Statistical Information—Manganese—Metaperiodate Spectrophotometric Method
Manganese Found, Repeatability Reproducibility
Test Material
% (R , E173) (R , E173)
1 2
1. Alloy steel (BCS 252, 0.016 Mn) 0.022 0.004 0.006
2. Alloy steel (BCS 255/1 0.16 Mn) 0.161 0.004 0.010
3. Low-alloy steel (NIST 72f, 0.545 Mn) 0.551 0.010 0.020
4. Low-alloy steel (NIST 139a, 0.780 Mn) 0.780 0.009 0.030
5. Alloy steel (NIST, 159, 0.807 Mn) 0.819 0.010 0.034
6. Carbon steel (NIST 13f, 0.889 Mn) 0.892 0.015 0.027
7. Low-alloy steel (NIST 100b, 1.89 Mn) 1.91 0.02 0.04
E350 − 23
19.2 The upper limit of the scope has been set at 0.09 % because sufficient numbers of test materials containing higher phosphorus
contents were unavailable for testing as directed in Practice E173. However, recognizing that the chemical principles used in this
test method are capable of handling higher compositions, the test method includes a calibration procedure up to 0.25 %. Users of
this test method are cautioned that its use above 0.09 % is not supported by interlaboratory testing.
20. Summary of Test Method
20.1 The sample is dissolved in mixed acids and the solution is fumed with HClO . Ammonium molybdate is added to react with
the phosphorus to form the heteropoly phosphomolybdate. This species is then reduced with hydrazine sulfate to form the
molybdenum blue complex. Spectrophotometric absorbance measurement is made at 650 nm or 825 nm, depending upon the
concentration.
21. Concentration Range
21.1 The recommended concentration range is from 0.005 mg to 0.05 mg of phosphorus per 100 mL of solution when measured
at 825 nm and from 0.05 mg to 0.3 mg of phosphorus per 100 mL of solution when measured at 650 nm, using a 1-cm cell.
NOTE 3—This test method has been written for cells having a 1-cm light path. Cells having other dimensions may be used, provided suitable adjustments
can be made in the amounts of sample and reagents used.
22. Stability of Color
22.1 The molybdenum blue complex is stable for at least 2 h.
23. Interferences
23.1 None of the elements usually present interfere except arsenic, which is removed by volatilization as the bromide.
24. Apparatus
24.1 Glassware must be phosphorus and arsenic-free. Boil the glassware with HCl and rinse with water before use. It is
recommended that the glassware used for this determination be reserved for this use only. Many detergents contain phosphorus
and must not be used for cleaning purposes.
25. Reagents
25.1 Ammonium Molybdate Solution (20 g/L)—Cautiously, while stirring and cooling, add 300 mL of H SO to 500 mL of water
2 4
and cool. Add 20 g of ammonium heptamolybdate ((NH ) Mo O ·4H O), cautiously dilute to 1 L, and mix.
4 6 7 24 2
25.2 Ammonium Molybdate-Hydrazine Sulfate Solution—Dilute 250 mL of the ammonium molybdate solution to 600 mL, add 100
mL of the hydrazine sulfate solution, dilute to 1 L, and mix. Do not use a solution that has stood for more than 1 h.
25.3 Hydrazine Sulfate Solution (1.5 g/L)—Dissolve 1.5 g of hydrazine sulfate ((NH ) ·H SO ) in water, dilute to 1 L, and mix.
2 2 2 4
Discard any unused solution after 24 h.
25.4 Phosphorus Standard Solution A (1 mL = 1.0 mg P)—Transfer 2.292 g of anhydrous disodium hydrogen phosphate
(Na HPO ), previously dried to constant mass at 105 °C, to a 500-mL volumetric flask; dissolve in about 100 mL of water, dilute
2 4
to volume, and mix.
25.5 Phosphorus Standard Solution B (1 mL = 0.01 mg P)—Using a pipet, transfer 10 mL of Solution A (1 mL = 1.0 mg P) to
a 1-L volumetric flask, add 50 mL of HClO (1 + 5), dilute to volume, and mix.
25.6 Phosphorus Standard Solution C (1 mL = 0.10 mg P)—Using a pipet, transfer 50 mL of Solution A (1 mL = 1.0 mg P) to
a 500-mL volumetric flask, add 50 mL of HClO (1 + 5), dilute to volume, and mix.
E350 − 23
25.7 Sodium Sulfite Solution (100 g/L)—Dissolve 100 g of sodium sulfite (Na SO ) in water, dilute to 1 L, and mix.
2 3
26. Preparation of Calibration Curve for Concentrations from 0.005 mg/100 mL to 0.05 mg/100 mL
26.1 Calibration Solutions—Using pipets, transfer (5, 10, 15, 25, and 50) mL of Phosphorus Standard Solution B (1 mL = 0.01
mg P) to 100-mL volumetric flasks. Add 20 mL of HClO , dilute to volume, and mix. Using a pipet, transfer 10 mL of each solution
to a 100-mL borosilicate glass volumetric flask. Proceed as directed in 26.3.
26.2 Reagent Blank—Transfer 12 mL of HClO (1 + 5) to a 100-mL borosilicate glass volumetric flask.
26.3 Color Development:
26.3.1 Add 15 mL of Na SO solution, boil gently for 30 s, and add 50 mL of ammonium molybdate-hydrazine sulfate solution
2 3
that has been prepared within the hour.
26.3.2 Heat the solutions at not less than 90 °C for 20 min, quickly cool, dilute to volume, and mix.
NOTE 4—Immersing the flasks in a boiling water bath is the preferred means of heating them for complete color development.
26.4 Reference Solution—Water.
26.5 Spectrophotometry:
26.5.1 Multiple-Cell Spectrophotometer—Measure the reagent blank (which includes the cell correction) versus the reference
solution (26.4) using absorption cells with a 1-cm light path and using a light band centered at 825 nm. Using the test cell, take
the spectrophotometric absorbance readings of the calibration solutions versus the reference solution.
26.5.2 Single-Cell Spectrophotometer—Transfer a suitable portion of the reference solution (26.4) to an absorption cell with a
1-cm light path and adjust the spectrophotometer to the initial setting using a light band centered at 825 nm. While maintaining
this adjustment, take the spectrophotometric absorbance readings of the reagent blank solution and of the calibration solutions.
26.6 Calibration Curve—Follow the instrument manufacturer’s instructions for generating the calibration curve. Plot the net
spectrophotometric absorbance readings of the calibration solutions against milligrams of phosphorus per 100 mL of solution.
27. Preparation of Calibration Curve for Concentrations from 0.05 mg/100 mL to 0.30 mg/100 mL
27.1 Calibration Solutions—Using pipets, transfer (5, 10, 15, 20, 25, and 30) mL of Phosphorus Standard Solution C (1 mL = 0.10
mg P) to 100-mL volumetric flasks. Add 20 mL of HClO , dilute to volume, and mix. Using a pipet, transfer 10 mL of each solution
to a 100-mL borosilicate glass volumetric flask.
27.2 Reagent Blank—Proceed as directed in 26.2.
27.3 Color Development—Proceed as directed in 26.3.
27.4 Reference Solution—Water.
27.5 Spectrophotometry:
27.5.1 Multiple-Cell Spectrophotometer—Measure the reagent blank (which includes the cell correction) versus the reference
solution (27.4) using absorption cells with a 1-cm light path and a light band centered at 650 nm. Using the test cell, take the
spectrophotometric absorbance readings of the calibration solutions versus the reference solution.
27.5.2 Single-Cell Spectrophotometer—Transfer a suitable portion of the reference solution (27.4) to an absorption cell with a
E350 − 23
1-cm light path and adjust the spectrophotometer to the initial setting using a light band (no change) centered at 650 nm. While
maintaining this adjustment, take the spectrophotometric absorbance readings of the reagent blank solution and of the calibration
solutions.
27.6 Calibration Curve—Follow the instrument manufacturer’s instructions for generating the calibration curve. Plot the net
spectrophotometric absorbance readings of the calibration solutions against milligrams of phosphorus per 100 mL of solution.
28. Procedure
28.1 Test Solution:
28.1.1 Transfer a 1.0-g sample, weighed to the nearest 0.5 mg, to a 250-mL Erlenmeyer flask.
28.1.2 Add 15 mL of a freshly prepared mixture of 1 volume of HNO and 3 volumes of HCl, slowly and in small portions. When
the reaction has ceased, add 10 mL of HClO and evaporate to fumes. Remove the flask immediately to avoid undue loss of HClO ,
4 4
cool, and add 20 mL of HBr (1 + 4). Evaporate the solution to copious whit fumes and then, without delay, fume strongly enough
to cause the white fumes to clear the neck of the flask, and continue at this rate for 1 min.
28.1.3 Cool the solution, add 60 mL of HClO (1 + 5), and swirl to dissolve the salts. Transfer to a 100-mL volumetric flask, cool,
dilute to volume, and mix. Allow insoluble matter to settle or dry filter the solution. Using a pipet, transfer 10-mL portions to two
100-mL borosilicate glass volumetric flasks; treat one as directed in 28.3 and the other as directed in 28.4.2.
28.2 Reagent Blank Solution—Carry a reagent blank through the entire procedure using the same amount of all reagents with the
sample omitted.
28.3 Color Development—Proceed with one of the 10-mL portions obtained in 28.1.3, as directed in 26.3.
28.4 Reference Solutions:
28.4.1 Water—Use this as the reference solution for the reagent blank solution.
28.4.2 Background Color Reference Solution—Add 15 mL of Na SO solution to the second 10-mL portion obtained in 28.1.3.
2 3
Boil gently for 30 s, add 50 mL of H SO (3 + 37), cool, dilute to volume, and mix. Use this as the reference solution for the test
2 4
solution.
28.5 Spectrophotometry—Take the spectrophotometric absorbance readings of the reagent blank solution and of the test solution
(using the respective reference solutions) as directed in 26.5 or 27.5 depending upon the estimated level of phosphorus in the
sample.
29. Calculation
29.1 Convert the net spectrophotometric absorbance reading of the test solution and of the reagent blank solution to milligrams
of phosphorus by means of the appropriate calibration curve. Calculate the percent of phosphorus as follows:
Phosphorus, %5 A 2 B / C ×10 (2)
~ ! ~ !
where:
A = phosphorus found in 100 mL of the final test solution, mg,
B = phosphorus found in 100 mL of the final reagent blank solution, mg, and
C = sample represented in 100 mL of the final test solution, g.
30. Precision and Bias
30.1 Precision—Nine laboratories cooperated in testing this test method and obtained the data summarized in Table 2.
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TABLE 2 Statistical Information—Phosphorus—Molybdenum Blue Spectrophotometric Method
Phosphorus Found, Repeatability Reproducibility
Test Material
% (R , E173) (R , E173)
1 2
1. Ingot iron (NIST 55e, 0.003 P) 0.002 0.001 0.002
2. Carbon steel (NIST 12g, 0.014 P) 0.014 0.002 0.003
3. Carbon steel (NIST 10g, 0.086 P) 0.084 0.006 0.009
30.2 Bias—The accuracy of this test method has been deemed satisfactory based upon the data for the certified reference materials
in Table 2. Users are encouraged to use these or similar reference materials to verify that the test method is performing accurately
in their laboratories.
SULFUR BY THE GRAVIMETRIC METHOD
(This test method, which consisted of Sections 31 through 36 of this standard, was discontinued in 1988.)
SULFUR BY THE COMBUSTION-IODATE TITRATION METHOD
(This test method, which consisted of Sections 37 through 45 of this standard, was discontinued in 2017.)
SILICON BY THE GRAVIMETRIC METHOD
46. Scope
46.1 This test method covers the determination of silicon from 0.05 % to 3.5 %.
46.2 The upper limit of the scope has been set at 3.5 % because test materials containing higher silicon contents were unavailable
for testing as directed in Practice E173. However, recognizing that the chemical principles used in this test method are capable of
handling higher compositions, the test method should be expandable to at least 5 %. Users of this test method are cautioned that
its use above 3.5 % is not supported by interlaboratory testing.
47. Summary of Test Method
47.1 After dissolution of the sample, silicic acid is dehydrated by fuming with H SO or HClO . The solution is filtered, and the
2 4 4
impure silica is ignited and weighed. The silica is then volatilized with HF. The residue is ignited and weighed; the loss in mass
represents silica.
48. Interferences
48.1 The elements normally present do not interfere if their compositions are under the maximum limits shown in 1.1.
49. Reagents
49.1 The analyst should ensure, by analyzing blanks and other checks, that possible silicon contamination of reagents will not
significantly bias the results.
49.2 HClO :
49.2.1 Select a lot of HClO that contains not more than 0.0002 % silicon for the analysis of samples containing silicon in the
range from 0.02 % to 0.10 % and not more than 0.0004 % silicon for samples containing more than 0.10 % by determining
duplicate values for silicon as directed in 49.2.2 – 49.2.6.
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49.2.2 Transfer 15 mL of HClO (Note 5) to each of two 400-mL beakers. To one of the beakers transfer an additional 50 mL of
HClO . Using a pipet, transfer 20 mL of Na SiO solution (1 mL = 1.00 mg Si) to each of the beakers. Evaporate the solutions
4 2 3
to fumes and heat for 15 min to 20 min at such a rate that HClO refluxes on the sides of the beakers. Cool sufficiently, and add
100 mL of water (40 °C to 50 °C).
NOTE 5—The 15-mL addition of HClO can be from the same lot as the one to be tested. Once a lot has been established as having less than 0.0002 %
silicon, it should preferably be used for the 15-mL addition in all subsequent tests of other lots of acid.
49.2.3 Add paper pulp and filter immediately, using low-ash 11-cm medium-porosity filter papers. Transfer the precipitates to the
papers, and scrub the beakers thoroughly with a rubber-tipped rod. Wash the papers and precipitates alternately with 3 mL to 5
mL portions of hot HCl (1 + 19) and hot water, for a total of 6 times. Finally wash the papers twice with H SO (1 + 49). Transfer
2 4
the papers to platinum crucibles.
49.2.4 Dry the papers and heat at 600 °C until the carbon is removed. Finally ignite at 1100 °C to 1150 °C to constant mass (at
least 30 min). Cool in a desiccator and weigh.
49.2.5 Add enough H SO (1 + 1) to moisten the SiO , and add 3 mL to 5 mL of HF. Evaporate to dryness and then heat at a
2 4 2
gradually increasing rate until H SO is removed. Ignite for 15 min at 1100 °C to 1150 °C, cool in a desiccator, and weigh.
2 4
49.2.6 Calculate the percent of silicon as follows:
Silicon, %5 @~A 2 B! 2 ~C 2 D!# ×0.4674/E ×100 (3)
where:
A = initial mass of crucible plus impure SiO when 65 mL of HClO was taken, g,
2 4
B = final mass of crucible plus impurities when 65 mL of HClO was taken, g,
C = initial mass of crucible plus impure SiO when 15 mL of HClO was taken, g,
2 4
D = final mass of crucible plus impurities when 15 mL of HClO was taken, g, and
E = nominal mass (80 g) of 50 mL of HClO .
49.3 Sodium Silicate Solution—Transfer 11.0 g of sodium silicate (Na SiO ·9H O) to a 400-mL beaker. Add 150 mL of water and
2 3 2
dissolve the salt. Filter through a medium paper, collecting the filtrate in a 1-L volumetric flask, dilute to volume, and mix. Store
in a polyethylene bottle. Use this solution to determine the suitability of the HClO .
49.4 Tartaric Acid Solution (20.6 g/L)—Dissolve 20.6 g of tartaric acid (C H O ) in water, dilute to 1 L, and filter.
4 6 6
50. Procedure
50.1 Select and weigh a sample as follows:
Tolerance in Dehydrating Acid, mL
Sample Sample H SO
2 4
Silicon, % mass, g mass, mg (1 + 4) HClO
0.05 to 0.10 5.0 5 150 75
0.10 to 1.0 4.0 4 100 60
1.0 to 2.0 3.0 3 100 50
2.0 to 5.0 2.0 2 100 40
Transfer the sample to a 400-mL beaker or a 300-mL porcelain casserole. Proceed as directed in 50.2 or 50.3.
50.2 H SO Dehydration:
2 4
50.2.1 Add amounts of HCl or HNO , or mixtures and dilutions of these acids, that are sufficient to dissolve the sample; and then
add the H SO (1 + 4) as specified in 50.1, and cover. Heat until dissolution is complete. Remove and rinse the cover glass;
2 4
substitute a ribbed cover glass.
50.2.2 Evaporate until salts begin to separate; at this point evaporate the solution rapidly to the first appearance of fumes and fume
strongly for 2 min to 3 min. Cool sufficiently, and add 100 mL of water (40 °C to 50 °C). Stir to dissolve the salts and heat, if
necessary, but do not boil. Proceed immediately as directed in 50.4.
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50.3 HClO Dehydration:
50.3.1 Add amounts of HCl or HNO , or mixtures and dilutions of these acids, which are sufficient to dissolve the sample, and
cover. Heat until dissolution is complete. Add HNO to provide a total of 35 mL to 40 mL, followed by HClO as specified in the
3 4
table in 50.1. Remove and rinse the cover glass; substitute a ribbed cover glass.
50.3.2 Evaporate the solution to fumes and heat for 15 min to 20 min at such a rate that the HClO refluxes on the sides of the
container. Cool sufficiently and add 100 mL of water (40 °C to 50 °C). Stir to dissolve the salts and heat to boiling. If the sample
solution contains more than 100 mg of chromium, add, while stirring, 1 mL of tartaric acid solution for each 25 mg of chromium.
50.4 Add paper pulp and filter immediately, on a low-ash 11-cm medium-porosity filter paper. Collect the filtrate in a 600-mL
beaker. Transfer the precipitate to the paper, and scrub the container thoroughly with a rubber-tipped rod. Wash the paper and
precipitate alternately with 3 mL to 5 mL portions of hot HCl (1 + 19) and hot water until iron salts are removed but for not more
than a total of ten washings. If 50.3 was followed, wash the paper twice more with H SO (1 + 49), but do not collect these
2 4
washings in the filtrate; discard the washings. Transfer the paper to a platinum crucible and reserve.
50.5 Add 15 mL of HNO to the filtrate, stir, and evaporate as directed in either 50.2 or 50.3, depending upon the dehydrating
acid used. Filter immediately, using a low-ash, 9-cm-100-porosity filter paper, and wash as directed in 50.4.
50.6 Transfer the paper and precipitate to the reserved platinum crucible. Dry the papers and then heat the crucible at 600 °C until
the carbon is removed. Finally ignite at 1100 °C to 1150 °C to constant mass (at least 30 min). Cool in a desiccator and weigh.
50.7 Add enough H SO (1 + 1) to moisten the impure SiO , and add 3 mL to 5 mL of HF. Evaporate to dryness and then heat
2 4 2
at a gradually increasing rate until H SO is removed. Ignite at 1100 °C to 1150 °C for 15 min, cool in a desiccator, and weigh.
2 4
51. Calculation
51.1 Calculate the percent of silicon as follows:
Silicon, %5 @~~A 2 B! ×0.4674!/C# ×100 (4)
where:
A = initial mass of crucible and impure SiO , g,
B = final mass of crucible and residue, g, and
C = sample used, g.
52. Precision and Bias
52.1 Precision—Eleven laboratories cooperated in testing this test method and obtained the data summarized in Table 3.
TABLE 3 Statistical Information—Silicon—Gravimetric Method
Silicon Found, Repeatability Reproducibility
Test Material
% (R , E173) (R , E173)
1 2
HCIO Dehydration
1. Carbon steel 0.053 0.015 0.036
2. Carbon steel (NIST 14d, 0.126 Si) 0.127 0.011 0.011
3. Carbon steel (NIST 19g, 0.186 Si) 0.186 0.011 0.010
4. Carbon steel (NIST 12g, 0.187 Si) 0.187 0.011 0.012
5. Low-alloy steel (NIST 32e, 0.278 Si) 0.280 0.011 0.012
6. Carbon steel (NIST 20f, 0.299 Si) 0.300 0.012 0.016
7. Electrical steel (NIST 125a, 3.32 Si) 3.33 0.07 0.07
H SO Dehydration
2 4
1. Carbon steel 0.046 0.009 0.013
2. Carbon steel (NIST 14d, 0.126 Si) 0.128 0.016 0.016
3. Carbon steel (NIST 19g, 0.186 Si) 0.186 0.014 0.019
4. Carbon steel (NIST 12g, 0.187 Si) 0.188 0.007 0.016
5. Low-alloy steel (NIST 32e, 0.278 Si) 0.282 0.015 0.024
6. Carbon steel (NIST 20f, 0.299 Si) 0.302 0.015 0.015
7. Electrical steel (NIST 125a, 3.32 Si) 3.33 0.05 0.05
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52.2 Bias—The accuracy of this test method has been deemed satisfactory based upon the data for the certified reference materials
in Table 3. Users are encouraged to use these or similar reference materials to verify that the test method is performing accurately
in their laboratories.
COBALT BY THE NITROSO-R-SALT SPECTROPHOTOMETRIC METHOD
53. Scope
53.1 This test method covers the determination of cobalt from 0.01 % to 0.30 %.
54. Summary of Test Method
54.1 The sample solution is treated with zinc oxide to remove iron, chromium, and vanadium. Nitroso-R-salt solution is added
to a portion of the filtrate which has been buffered with sodium acetate to produce an orange-colored complex with cobalt. The
addition of nitric acid stabilizes the cobalt complex and also destroys certain interfering complexes. Spectrophotometric
absorbance measurement is made at 520 nm.
55. Concentration Range
55.1 The recommended concentration range is from 0.005 mg to 0.15 mg of cobalt per 50 mL of solution, using a 1-cm cell.
NOTE 6—This test method has been written for cells having a 1-cm light path. Cells having other dimensions may be used, provided suitable adjustments
can be made in the amounts of sample and reagents used.
56. Stability of Color
56.1 The color is stable for at least 3 h.
57. Interferences
57.1 Nickel, manganese, and copper form complexes with nitroso-R-salt that deplete the reagent and inhibit the formation of the
colored cobalt complex. A sufficient amount of nitroso-R-salt is used to provide full color development with 0.15 mg of cobalt in
the presence of 41 mg of nickel, 1.5 mg of manganese, and 5 mg of copper, or 48 mg of nickel only. Colored complexes of nickel,
manganese, and copper are destroyed by treating the hot solution with HNO .
58. Reagents
58.1 Cobalt, Standard Solution (1 mL = 0.06 mg Co)—Dry a weighing bottle and stopper in an oven at 130 °C for 1 h, cool in
a desiccator, and weigh. Transfer approximately 0.789 g of cobalt sulfate (CoSO ) that has been heated at 550 °C for 1 h to the
weighing bottle. Dry the bottle and contents at 130 °C for 1 h, cool in a desiccator, stopper the bottle, and weigh. The difference
in mass is the exact amount of CoSO taken. Transfer the weighed CoSO to a 400-mL beaker, rinse the weighing bottle with water,
4 4
and transfer the rinsings to the beaker. Add 150 mL of water and 10 mL of HCl, and heat to dissolve the salts. Cool, transfer to
a 500-mL volumetric flask, dilute to volume, and mix. By means of a pipet, transfer a 50-mL aliquot of this solution to a 500-mL
volumetric flask, dilute to volume, and mix. The exact concentration (in milligrams of cobalt per millilitre) of the final solution
is the ex
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