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: E1587 − 17

Standard Test Methods for

Chemical Analysis of Refined Nickel1
This standard is issued under the fixed designation E1587; 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.

1. Scope 1.3 The values stated in SI units are to be regarded as

1.1 These test methods apply to the chemical analysis of standard. No other units of measurement are included in this
refined nickel and other forms of metallic nickel having standard.
chemical compositions within the following limits: 1.4 This standard does not purport to address all of the
Element Mass Fraction, % safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
Antimony, less than 0.005 priate safety and health practices and determine the applica-
Arsenic, less than 0.005
Bismuth, less than 0.01 bility of regulatory limitations prior to use. For specific
Cadmium, less than 0.0025 precautions, see Section 6.
Carbon, max 0.03 1.5 This international standard was developed in accor-
Cobalt, max 1.00
Copper, max 1.00 dance with internationally recognized principles on standard-
Hydrogen, max 0.003 ization established in the Decision on Principles for the
Iron, max 0.15 Development of International Standards, Guides and Recom-
Lead, less than 0.01
Manganese, less than 0.20 mendations issued by the World Trade Organization Technical
Nickel, min 98.0 Barriers to Trade (TBT) Committee.
Nitrogen, less than 0.50
Oxygen, less than 0.03 2. Referenced Documents
Phosphorus, less than 0.005
Selenium, less than 0.0010 2.1 ASTM Standards:2
Silicon, less than 0.005
Silver, less than 0.01
D1193 Specification for Reagent Water
Sulfur, max 0.01 E29 Practice for Using Significant Digits in Test Data to
Tellurium, less than 0.0010 Determine Conformance with Specifications
Thallium, less than 0.0010
Tin, less than 0.005
E50 Practices for Apparatus, Reagents, and Safety Consid-
Zinc, less than 0.015 erations for Chemical Analysis of Metals, Ores, and
1.2 These test methods may be used to determine the Related Materials
following elements by the methods indicated below: E60 Practice for Analysis of Metals, Ores, and Related
Materials by Spectrophotometry
Test Methods Sections
E135 Terminology Relating to Analytical Chemistry for
Antimony, Arsenic, Bismuth, Cadmium, 21 – 31 Metals, Ores, and Related Materials
Lead, Selenium, Silver, Tellurium, Tin,
and Thallium by the Graphite Furnace
E1024 Guide for Chemical Analysis of Metals and Metal
Atomic Absorption Spectrometric Method Bearing Ores by Flame Atomic Absorption Spectropho-
tometry (Withdrawn 2004)3
Bismuth, Cadmium, Cobalt, Copper, Iron, 9 – 20
Lead, Manganese, Silver, and Zinc by the
E1601 Practice for Conducting an Interlaboratory Study to
Flame Atomic Absorption Spectrometric Evaluate the Performance of an Analytical Method
Method 2.2 ISO Standard:4
Sulfur by the Methylene Blue Spectro- 32 – 42
ISO 5725 Precision of Test Methods—Determination of Re-
photometric Method After Generation of peatability and Reproducibility by Interlaboratory Tests
Hydrogen Sulfide

2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
1
These test methods are under the jurisdiction of ASTM Committee E01 on Standards volume information, refer to the standard’s Document Summary page on
Analytical Chemistry for Metals, Ores, and Related Materials and are the direct the ASTM website.
3
responsibility of Subcommittee E01.08 on Ni and Co and High Temperature Alloys. The last approved version of this historical standard is referenced on
Current edition approved April 1, 2017. Published June 2017. Originally www.astm.org.
4
approved in 1994. Last previous edition approved in 2010 as E1587 – 10. DOI: Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/E1587-17. 4th Floor, New York, NY 10036, http://www.ansi.org.

Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States

1
 E1587 − 17
3. Terminology 6.2 Where appropriate, specific precautionary information
3.1 For definitions of terms used in this test method, refer to is given in the Hazards sections and in special warning
Terminology E135. paragraphs.
7. Sampling
4. Significance and Use
7.1 Sampling shall be carried out by a mutually acceptable
4.1 These test methods are primarily intended to test refined method.
nickel metal for compliance with compositional specifications.
It is assumed that all who use these test methods will be trained 7.2 The laboratory sample normally is in the form of a
analysts capable of performing common laboratory procedures powder, granules, millings, or drillings and no further prepa-
skillfully and safely. It is expected that the analytical work will ration is necessary.
be performed in a properly equipped laboratory under appro- 7.3 If it is suspected that the laboratory sample is contami-
priate quality control practices. nated with oil or grease from the milling or drilling process, it
may be cleaned by washing with high-purity acetone and
5. Apparatus, Reagents, and Instrumental Practices drying in air.
5.1 Apparatus: 7.4 If the laboratory sample contains particles or pieces of
5.1.1 Special apparatus and reagents required for each widely varying sizes, the test sample should be obtained by
determination are listed in the Apparatus section of each test riffling or coning and quartering techniques.
method.
5.1.2 Glass storage containers shall be of borosilicate glass. 8. Rounding Calculated Values
5.1.3 Plastic containers shall be polyethylene or preferably 8.1 Calculated values shall be rounded to the desired num-
polytetrafluoroethylene (PTFE). ber of places in accordance with the rounding method in
5.2 Reagents: Practice E29.
5.2.1 Purity of Reagents—Reagent grade chemicals shall be SILVER, BISMUTH, CADMIUM, COBALT, COPPER,
used in all tests. Unless otherwise indicated, it is intended that IRON, MANGANESE, LEAD, AND ZINC BY FLAME
all reagents conform to the specifications of the Committee on ATOMIC ABSORPTION SPECTROMETRY
Analytical Reagents of the American Chemical Society where
such specifications are available.5 Other grades may be used, 9. Scope
provided it is first ascertained that the reagent is of sufficiently 9.1 This test method applies to the determination of the
high purity to permit its use without lessening the accuracy of silver, bismuth, cadmium, cobalt, copper, iron, manganese,
the determination. lead, and zinc contents of refined, wrought, and cast nickel
5.2.2 Purity of Water—Unless otherwise indicated, refer- metal within the following ranges.
ences to water shall be understood to mean reagent water as Mass Fraction Range, %
defined by Type II of Specification D1193. Element Method A Method B
5.2.3 Reagents and their preparation are described in the
Silver 0.0002 to 0.01 ...
Reagents section in each test method. Bismuth 0.0010 to 0.01 ...
5.2.4 Instructions for the preparation of standard solutions Cadmium 0.0002 to 0.0025 ...
used in these test methods frequently call for measuring exact Cobalt 0.0010 to 0.01 0.01 to 1.00
Copper 0.0005 to 0.01 0.01 to 1.00
masses of substances of known composition so that the Iron 0.0025 to 0.01 0.01 to 0.15
concentrations of the resulting standard stock solutions can be Manganese 0.0005 to 0.01 0.01 to 0.20
expressed using simple numbers. Small variations from these Lead 0.0006 to 0.01 ...
Zinc 0.0005 to 0.0025 0.001 to 0.015
specified quantities are acceptable, provided that the true
weighed masses are used to calculate the concentration of the 9.2 This test method is applicable to the independent deter-
prepared solutions and then these calculated values are used mination of any one or more of the elements listed without
throughout the test methods. including all the elements specified in the calibration solutions.
5.3 Instrumental Practices—Information on the use of some 9.3 The lower level for iron can be extended to less than
instrumental techniques employed in these test methods are 0.0025 % provided nickel metal containing less than 0.0001 %
described in Practice E60 and in Guide E1024. iron is used for preparation calibration solutions.
9.4 The upper limit for the determination of cobalt and
6. Hazards copper can be raised to 2 % by a minor modification to the test
6.1 For precautions to be observed in the use of certain method. For test samples containing greater than 0.25 % and
reagents and equipment in these test methods, refer to Practices less than 2 % of cobalt or copper, further dilutions of the test
E50. solution with HNO3 (1 + 19) may be made. The nickel content
of the calibration solutions should be matched with those of the
test solutions.
5
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
9.5 This international standard was developed in accor-
listed by the American Chemical Society, see the United States Pharmacopeia and dance with internationally recognized principles on standard-
National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD. ization established in the Decision on Principles for the

2
 E1587 − 17
Development of International Standards, Guides and Recom- 1000-mL may be used. The amount of HNO3 should be
mendations issued by the World Trade Organization Technical increased in proportion. Even larger sample masses can be
Barriers to Trade (TBT) Committee. used, with greater amounts of HNO3 to prepare a more
concentrated nickel test solution. However, an aliquot portion
10. Summary of Test Method to correspond to a 5-g sample must be taken from such a
10.1 The sample is dissolved in dilute HNO3, excess acid is solution and processed in accordance with the procedure given
evaporated, and the solution diluted to a known volume. The to give a test solution containing 25 g/L of nickel to match the
test solution is aspirated into the air/acetylene flame of an calibration solutions.
atomic absorption spectrometer. The absorption of the reso- 13.2 Cadmium, Standard Stock Solution (1 mL = 1 mg
nance line energy from the spectrum of each element is Cadmium)—Transfer a 1.00-g sample of cadmium metal
measured and compared with that from a set of calibration (purity, 99.9 % minimum), weighed to the nearest 0.001 g, to a
solutions of the same element in a matched nickel matrix. 600-mL beaker. Proceed as directed in 13.1.2.
11. Interferences 13.3 Cobalt, Standard Stock Solution (1 mL = 1 mg
11.1 Elements ordinarily present in nickel metal do not Cobalt)—Transfer a 1.00-g sample of cobalt metal (purity,
present spectral interferences in the atomic absorption analysis. 99.9 % minimum), weighed to the nearest 0.001 g, to a 600-mL
beaker. Proceed as directed in 13.1.2.
11.2 For the determination of silver, take care to avoid
contamination of the sample and calibration solutions with 13.4 Copper, Standard Stock Solution (1 mL = 1 mg
chloride. Copper)—Transfer a 1.00-g sample of copper metal (purity,
99.9 % minimum), weighed to the nearest 0.001 g, to a 600-mL
11.3 Potential background absorption interference is elimi- beaker. Proceed as directed in 13.1.2.
nated by use of matched matrix calibration solutions prepared
from high-purity nickel metal. See Note 1. 13.5 Iron, Standard Stock Solution (1 mL = 1 mg Iron)—
Transfer a 1.00-g sample of iron metal (purity, 99.9 %
NOTE 1—In this test method, any effect of nonspecific absorption and
light scatter is compensated for by matching the matrix of the calibration
minimum), weighed to the nearest 0.001 g, to a 600-mL beaker.
solutions with the test solutions. Also, since the same lot of HNO3 is used Proceed as directed in 13.1.2.
for both calibration and test solutions, the reagent blank is incorporated in
the calibration curve. Thus, the calibration curve may not pass through the
13.6 Lead, Standard Stock Solution (1 mg = 1 mg Lead)—
origin. Transfer a 1.00-g sample of lead metal (purity, 99.9 %
minimum), weighed to the nearest 0.001 g, to a 600-mL beaker.
12. Apparatus Proceed as directed in 13.1.2.
12.1 Atomic Absorption Spectrometer: 13.7 Manganese, Standard Stock Solution (1 mL = 1 mg
12.1.1 The atomic absorption spectrometer used in this test Manganese)—Transfer a 1.00-g sample of manganese metal
method should meet the instrument performance parameters in (purity, 99.9 % minimum), weighed to the nearest 0.001 g, to a
accordance with Guide E1024. 600-mL beaker. Proceed as directed in 13.1.2.
12.1.2 The instrument shall be equipped with a burner head
capable of accepting a solution containing 25 g ⁄L of nickel, as 13.8 Nickel Powder—High-purity, containing less than
nitrate, and suitable for an air/acetylene flame. 0.0005 % iron and less than 0.0001 % each of silver, bismuth,
12.1.3 The instrument should be capable of using single- cadmium, cobalt, copper, manganese, lead, and zinc.
element hollow cathode or electrodeless discharge lamps 13.9 Silver, Standard Stock Solution (1 mL = 1 mg Silver)—
operated at currents recommended by the instrument manufac- Transfer a 1.00-g sample of silver metal (purity, 99.9 %
turer. minimum), weighed to the nearest 0.001 g, to a 600-mL beaker.
Proceed as directed in 13.1.2, except store in an amber glass
13. Reagents container.
13.1 Bismuth, Standard Stock Solution (1 mL = 1 mg Bis- 13.10 Zinc, Standard Stock Solution (1 mL = 1 mg Zinc)—
muth): Transfer a 1.00-g sample of zinc metal (purity, 99.9 %
13.1.1 Transfer a 1.00-g sample of bismuth metal (purity, minimum), weighed to the nearest 0.001 g, to a 600-mL beaker.
99.9 % minimum), weighed to the nearest 0.001 g, to a 600-mL Proceed as directed in 13.1.2.
beaker.
13.1.2 Add 40 mL of HNO3 (1 + 1) and heat gently until 13.11 Working Solutions:
dissolution is complete. Boil gently to expel oxides of nitrogen 13.11.1 Mixed Analyte Standard Solution A (1 mL = 20 µg
and cool. Transfer to a 1-L volumetric flask containing 160 mL of silver, bismuth, cadmium, cobalt, copper, iron, manganese,
of HNO3 (1 + 1), dilute to volume with water, and mix. Store and lead and 10 µg of zinc)—Using pipets, transfer 20.0 mL of
in a polyethylene or PTFE bottle. Use the same batch of HNO3 each of the standard stock solutions for silver, bismuth,
throughout the entire procedure. cadmium, cobalt, copper, iron, manganese, and lead and 10 mL
13.1.3 If inhomogeneity is suspected in the test sample, or if of the standard stock solution for zinc to a 1-L volumetric flask
the sample pieces are relatively large, a larger sample mass containing 160 mL of HNO3 (1 + 1). Use the same batch of
should be used to prepare the test solution. Under such HNO3 throughout the entire procedure. Dilute to volume with
circumstances, a sample mass of 25 g in a final volume of water and mix. Store in a glass container.

3
 E1587 − 17
13.11.2 Mixed Analyte Standard Solution B (1 mL = 100 µg nickel powder. This blank is then compared with the standard
of cobalt, copper, iron, and manganese and 10 µg of zinc)— zero calibration solution and an appropriate correction made.
Using pipets, transfer 50.0 mL of the cobalt, copper, iron, and
manganese standard stock solutions and 5.0 mL of the zinc NOTE 3—For convenience, 80 g of nickel/L stock nickel nitrate solution
may be prepared by dissolving 20.0 g of nickel powder in water and
standard stock solution to a 500-mL volumetric flask contain- 120 mL of HNO3 (1 + 1) in an 800-mL beaker and filtering through
ing 80 mL of HNO3 (1 + 1). Dilute to volume and mix. Store acid-washed glass wool or a cellulose filter into a 250-mL volumetric
in a polyethylene or PTFE container. flask. Aliquots (25.0 mL) of this solution are then evaporated and
processed as directed in 14.2 and 15.2.
14. Calibration Solutions
15. Procedure A
14.1 Set A:
14.1.1 This set corresponds to (0, 0.2, 0.5, 1.0, 1.5, 2.0, and 15.1 This procedure is applicable to 0.0005 % to 0.01 % of
2.5) µg ⁄mL each of silver, bismuth, cadmium, cobalt, copper, silver, bismuth, cadmium, cobalt, copper, iron, manganese, and
iron, manganese, and lead and (0, 0.1, 0.25, 0.5, 0.75, 1.0, and lead and 0.0005 % to 0.005 % zinc.
1.25) µg ⁄L of zinc.
15.2 Preparation of Test Solution—Weigh, to the nearest
Analyte Concentration µ g/mL
0.01 g, 4.9 g, to 6.1 g of the test sample and transfer to a clean,
Silver, Bismuth, Cadmium, unetched 600-mL beaker. Add sufficient water to cover the
Aliquot of Cobalt, Copper, Iron, sample and dissolve by adding 60 mL of HNO3 (1 + 1) in
No. Solution A, mL Manganese, and Lead Zinc
1 0 0 0
small portions. Heat to complete dissolution, boil gently to
2 2.0 0.2 0.1 expel oxides of nitrogen, and evaporate to a viscous syrup.
3 5.0 0.5 0.25 Redissolve the salts by adding 20 mL HNO3 (1 + 1) and
4 10.0 1.0 0.5
5 15.0 1.5 0.75
100 mL of water. Heat to complete dissolution, cool, and filter,
6 20.0 2.0 1.0 if necessary, through either glass wool or a cellulose filter that
7 25.0 2.5 1.25 has been washed with HNO3 (1 + 1). Collect the filtrate in a
14.1.2 Weigh, to the nearest 0.01 g, seven separate 5.0-g 200-mL volumetric flask. Wash the filter with water, collecting
portions of high-purity nickel powder and transfer to 600-mL the washings, and dilute to volume with water and mix.
beakers. Treat as directed in 15.2 to the point of dilution. 15.2.1 If inhomogeneity is suspected in the test sample, or if
14.1.3 Add, using a buret graduated in 0.05-mL divisions, the sample pieces are relatively large, a larger sample mass
(0, 2.0, 5.0, 10.0, 15.0, 20.0, and 25.0) mL respectively of the should be used to prepare the test solution. Under such
mixed Analyte, Standard Solution A to the 200-mL volumetric circumstances, a sample mass of 25 g in a final volume of
flasks. Dilute to volume with water and mix. If it is impossible 1000-mL may be used. The amount of HNO3 should be
to use the same batch of HNO3, a second reagent blank shall be increased in proportion. Even larger sample masses can be
prepared using the same high-purity nickel powder. This blank used, with greater amounts of HNO3 to prepare a more
is then compared with the standard zero calibration solution concentrated nickel test solution. However, an aliquot portion
and an appropriate correction made. to correspond to a 5-g sample must be taken from such a
NOTE 2—The solution with zero addition is the reagent blank. See 15.3. solution and processed in accordance with the procedure given
to give a test solution containing 25 g/L of nickel to match the
14.2 Set B: calibration solutions.
14.2.1 This set corresponds to (0, 2.5, 5.0, 10.0, 15.0, 20.0,
and 25.0) µg ⁄mL of cobalt, copper, iron, and manganese and 15.3 Reagent Blank Solution—The zero reference solution
(0, 0.25, 0.5, 1.0, 1.5, 2.0, and 2.5) µg ⁄mL of zinc. of the Calibration Solution Set A (14.1) serves as the reagent
Analyte Concentration µ g/mL blank, since the same batch of HNO3 is used for dissolution of
Aliquot of Mixed both the nickel reference and test samples.
Analyte, Standard Cobalt, Copper, Iron,
No. Solution B, mL and Manganese Zinc 15.3.1 If it is impossible to use the same batch of HNO3, a
1 0 0 0 second reagent blank shall be prepared using the same high-
2 5.0 2.5 0.25 purity nickel powder. This blank is then compared with the
3 10.0 5.0 0.5
4 20.0 10.0 1.0 standard zero calibration solution and an appropriate correction
5 30.0 15.0 1.5 made.
6 40.0 20.0 2.0
7 50.0 25.0 2.5 15.4 Instrumental Parameters:
14.2.2 Weigh, to the nearest 0.005 g, seven separate 2.00-g 15.4.1 Use the spectral lines specified in the following table:
portions of high-purity nickel powder and transfer to 400-mL Spectral Lines—Procedure A
beakers. Dissolve as directed in 16.2.2.
Element Silver Bismuth Cadmium Cobalt Copper
14.2.3 Using a buret, add (0, 5.0, 10.0, 20.0, 30.0, 40.0, and Wavelength, nm 328.1 223.1 228.8 240.7 324.7
50.0) mL respectively of the mixed Analyte, Standard Solu-
tion B to the 200-mL volumetric flasks. Dilute to volume with Element Iron Manganese Lead Zinc
Wavelength, nm 248.3 279.5 217.0 213.9
water and mix. The solution with no analyte added is the blank.
If it is impossible to use the same batch of HNO3, a second 15.4.2 The alternative, less-sensitive spectral lines specified
reagent blank shall be prepared using the same high-purity in the following table may be used:

4
 E1587 − 17

Alternate Spectral Lines—Procedure A Spectral Lines—Procedure B

Element Cobalt Copper Iron Manganese Lead Element Cobalt Copper Iron Manganese Zinc
Wavelength, nm 241.2 327.4 252.3 403.1 283.3 Wavelength, nm 241.2 327.4 252.3 403.1 213.9

15.4.3 Set the required instrument parameters in accordance 16.4.2 Proceed as directed in 15.4.3 and 15.4.4.
with the manufacturer’s recommendations. Light the burner 16.5 Spectrometry:
and aspirate diluted HNO3 (1 + 19) until thermal equilibrium 16.5.1 Proceed as directed in 15.5.1 through 15.5.6, substi-
is reached. A fuel-lean air-acetylene flame shall be used. tuting the Set B calibration solution (14.2) for the Set A
15.4.4 Ensure that the instrument meets the performance solutions.
requirements given in Practice E60. Optimum settings for the 16.5.2 Proceed with the preparation of the calibrations
operating parameters vary from instrument to instrument. curves and calculations as directed in Sections 17 and 18.
15.5 Spectrometry:
17. Preparation of Calibration Curves
15.5.1 Ensure that the test solution (15.2) and the calibration
solutions, Set A (14.1) are within 1 °C of the same temperature. 17.1 Plot the average instrument reading against the con-
15.5.2 Aspirate diluted HNO3 (1 + 19) and zero the instru- centration of the analyte for the calibration solutions for each
ment. set of measurements.
15.5.3 Aspirate the test solution(s) and note the reading to 17.2 For instruments that have automated calibration fea-
determine its place within the set of calibration solutions. tures and direct read-out in concentration, plotting of calibra-
15.5.4 Aspirate diluted HNO3 (1 + 19) until the initial tion curves is not required. Follow the instrument operating
reading is obtained. Zero the instrument if necessary. instructions for calibration and curvature correction proce-
15.5.5 Aspirate the Set A calibration solutions (14.1) and the dures.
test solution(s) in order of increasing instrument response,
18. Calculations
starting with the zero reference solution. When a stable
response is obtained, record the reading. Flush the system by 18.1 Determine the concentration of analyte in the test
aspirating diluted HNO3 (1 + 19) between each test or cali- solution from the corresponding calibration curves or instru-
bration solution. Avoid aspirating the high-nickel solutions for ment read-out for each of the three sets of instrument readings.
long periods without flushing; otherwise, the burner may tend Average the resultant concentrations.
to clog. 18.2 Procedure A—Calculate the mass fraction of the ana-
15.5.6 Repeat the measurement of the full set of the lyte in the test sample as follows:
calibration and test solutions twice more and record the data. A 3B
See Note 1. Analyte, % 5
C
3 1024 (1)
15.5.7 Proceed with the preparation of the calibration
curves and calculations as directed in Sections 17 and 18. where:
A = analyte concentration found in the test solution, µg/mL,
16. Procedure B
B = volume of the test solution, mL, and
16.1 This procedure is applicable to 0.01 % to 0.25 % of C = mass of the test sample, g.
cobalt, copper, iron, and manganese and 0.005 % to 0.025 % of
zinc. 18.3 Procedure B:
18.3.1 For the procedure in 16.2.1, calculate mass fraction
16.2 Preparation of Test Solution: of the analyte in the test sample as follows:
16.2.1 If a test solution has been prepared by Procedure A
A 3B
(15.2), using a pipet, transfer a 100.0-mL aliquot portion into a Analyte, % 5 3 2.5 3 1024 (2)
C
250-mL volumetric flask, dilute to volume with diluted HNO3
(1 + 19). Otherwise, proceed as directed in 16.2.2. where 2.5 = correction factor for the dilution made.
16.2.2 Weigh to the nearest 0.005 g, 1.9 g to 2.1 g of the test
sample, transfer to a 400-mL beaker and dissolve in 20 mL of 19. Precision and Bias
HNO3 (1 + 1). Complete the preparation as directed in 15.2. 19.1 Precision:
19.1.1 Eighteen laboratories in nine countries participated
16.3 Reagent Blank Solution—The zero reference solution
in testing this method under the auspices of ISO/TC-155/SC-
of the calibration solution Set B (14.2) serves as the reagent
3/WG-1 in the early 1980s and obtained the statistical data
blank. If it is impossible to use the same batch of HNO3, a
summarized in Table 1 as evaluated by ISO 5725 and equiva-
second reagent blank shall be prepared using the same high-
lent to Practice E1601. Precision may be judged by examina-
purity nickel powder. This blank is then compared with the
tion of these data. Twelve sample were analyzed to cover the
standard zero calibration solution and an appropriate correction
scope of this test method. Of these, ten were specially prepared
made.
as no materials containing the impurity levels were available
16.4 Instrumental Parameters: commercially.
16.4.1 The spectral lines specified in the following table are 19.1.2 The laboratory test program was designed so that the
to be used in the analysis: statistics on repeatability would include variations because of a

5
 E1587 − 17
TABLE 1 Statistical Information—Flame AAS Method, if the nickel metal used for the preparation of the calibration
Procedure A solutions does not meet the purity specifications given in the
Repeatability Reproducibility, test method and appropriate corrections are not made.
Test Material Mean, % Index, r Index R
(Practice E1601) (Practice E1601)
Silver 20. Keywords
P45 0.00043 0.00003 0.00012
P44 0.00077 0.00005 0.00007
20.1 bismuth; cadmium; cobalt; copper; flame atomic ab-
P46 0.00095 0.00012 0.00015 sorption spectrometry; iron; lead; manganese; refined nickel;
P41 0.00191 0.00008 0.00017 silver; spectrometry; zinc
J63 0.00232 0.00010 0.00022
P43 0.00282 0.00017 0.00022 SILVER, ARSENIC, BISMUTH, CADMIUM, LEAD,
J61 0.00970 0.00025 0.00142
Bismuth ANTIMONY, SELENIUM, TIN, TELLURIUM, AND
P44 0.00133 0.00027 0.00076 THALLIUM BY THE GRAPHITE FURNACE ATOMIC
P41 0.00171 0.00028 0.00047
P43 0.00245 0.00031 0.00049
ABSORPTION SPECTROMETRY
J61 0.01037 0.00044 0.00057
Cadmium 21. Scope
P46 0.00019 0.00003 0.00008
J63 0.00025 0.00002 0.00009 21.1 This test method applies to the determination of the
J61 0.00135 0.00007 0.00025 silver, arsenic, bismuth, cadmium, lead, antimony, selenium,
S65 0.00225 0.00007 0.00025
Cobalt tin, tellurium, and thallium contents of high-purity, refined,
P43 0.00105 0.00007 0.00016 wrought, and cast nickel metal within the ranges specified in
P44 0.00155 0.00007 0.00040 the following table:
P41 0.00185 0.00011 0.00014
J62 0.00508 0.00023 0.00030 Element Mass Fraction Range, µg/g
J61 0.01002 0.00038 0.00060
Copper Silver 0.3 to 10
S65 0.00079 0.00012 0.00022 Arsenic 1.3 to 20
J62 0.00517 0.00009 0.00025 Bismuth 4.0 to 15
J61 0.01006 0.00009 0.00041 Cadmium 0.3 to 2
Iron Lead 0.7 to 10
P46 0.00241 0.00020 0.00059 Antimony 1.8 to 10
P45 0.00298 0.00033 0.00060 Selenium 1.8 to 10
P44 0.00311 0.00013 0.00058 Tin 2.2 to 5
P41 0.00437 0.00018 0.00103 Tellurium 1.5 to 10
S65 0.00474 0.00026 0.00058 Thallium 0.5 to 10
Manganese
P41 0.00054 0.00003 0.00020 21.2 This test method is applicable to the independent
P46 0.00070 0.00005 0.00020 determination of any one or more of the elements listed without
P45 0.00107 0.00008 0.00020 including all elements specified in the calibration solutions.
P43 0.00200 0.00005 0.00014
J62 0.00536 0.00013 0.00037 21.3 This international standard was developed in accor-
J61 0.01028 0.00027 0.00052
Lead
dance with internationally recognized principles on standard-
H79 0.00078 0.00003 0.00017 ization established in the Decision on Principles for the
P46 0.00090 0.00030 0.00036 Development of International Standards, Guides and Recom-
P41 0.00202 0.00032 0.00048
P44 0.00252 0.00024 0.00026
mendations issued by the World Trade Organization Technical
J62 0.00350 0.00011 0.00041 Barriers to Trade (TBT) Committee.
J63 0.00365 0.00017 0.00017
J61 0.00777 0.00020 0.00046
Zinc
22. Summary of Test Method
H79 0.00029 0.00004 0.00015
P44 0.00041 0.00004 0.00020
22.1 The test sample is dissolved in HNO3 and the solution
P41 0.00050 0.00007 0.00016 is diluted to a known volume. An aliquot is introduced into a
P46 0.00062 0.00008 0.00010 graphite furnace atomic absorption spectrometer (GF-AAS)
S65 0.00101 0.00009 0.00017
P43 0.00117 0.00009 0.00028
and the absorption of the resonance line energy from the
P45 0.00128 0.00023 0.00040 spectrum of each element is measured and compared with that
J62 0.00269 0.00014 0.00024 from a set of calibration solutions of the same element in a
matched nickel matrix. All readings are background-corrected.

23. Interferences
change in the atomic absorption instrument or operator, or
both, while maintaining the same test solution. 23.1 Elements ordinarily present in nickel metal do not
19.2 Bias—No information is currently available on the bias present spectral interferences in graphite furnace atomic ab-
of this test method, because of the lack of appropriate certified sorption analysis.
reference materials. The bias of a test method may be judged, 23.2 Potential background absorption interference is elimi-
however, by comparing accepted reference values with the nated by instrumental background correction and by the use of
arithmetic average obtained by interlaboratory testing. The matched-matrix calibration solutions prepared from high-
user is cautioned that the results will be biased to the low side purity nickel metal.

6
 E1587 − 17
23.3 The lower limit for the determination of the elements is 25.3 Bismuth, Standard Stock Solution (1 mL = 1 mg
affected by the residual level of each element in the high-purity Bismuth)—Transfer a 0.100-g sample of bismuth metal (purity,
nickel metal used to prepare the matched matrix standard stock 99.9 % minimum), weighed to the nearest 0.1 mg, to a 100-mL
solutions. beaker. Proceed as directed in 25.2.1.
23.4 For the determination of silver and tin, care must be 25.4 Cadmium, Standard Stock Solution (1 mL = 1 mg
taken to avoid contamination of the sample and calibration Cadmium)—Transfer a 0.100-g sample of cadmium metal
solutions with chloride ion. (purity, 99.9 % minimum), weighed to the nearest 0.1 mg, to a
23.5 Because of the high sensitivity of GF-AAS, stringent 100-mL beaker. Proceed as directed in 25.2.1.
precautions must be taken to clean all glassware and avoid 25.5 Lead, Standard Stock Solution (1 mL = 1 mg Lead)—
contamination of sample, standard stock, and calibration solu- Transfer a 0.100-g sample of lead metal (purity, 99.9 %
tions from foreign material and dust from the laboratory minimum), weighed to the nearest 0.1 mg, to a 100-mL beaker.
atmosphere. Proceed as directed in 25.2.1.

24. Apparatus 25.6 Nickel Metal, high-purity, containing less than 5 µg ⁄g

of iron and less than 1 µg ⁄g of silver, arsenic, bismuth,
24.1 Atomic Absorption Spectrometer and Graphite Fur- cadmium, lead, antimony, selenium, tin, tellurium, and thal-
nace Analyzer—The instrument shall be equipped with a lium.
background corrector and high-speed read-out electronics or a
high-speed recorder, or both. The instrument should also be 25.7 Selenium, Standard Stock Solution (1 mL = 1 mg
capable of using single element hollow cathode or electrode- Selenium)—Transfer a 0.100-g sample of selenium metal
less discharge lamps operated at currents recommended by the (purity, 99.9 % minimum), weighed to the nearest 0.1 mg, to a
lamp and instrument manufacturers. 100-mL beaker. Proceed as directed in 25.2.1.
24.2 Micropipets, 5 µL to 25 µL. 25.8 Silver, Standard Stock Solution (1 mL = 1 mg Silver)—
Transfer a 0.100-g sample of silver metal (purity, 99.9 %
24.3 Glass Storage Bottles—The glass bottles used to store minimum), weighed to the nearest 0.1 mg, to a 100-mL beaker.
mixed analyte standard stock and calibration solutions shall be Proceed as directed in 25.2.1, except store in an amber glass
of borosilicate glass, thoroughly cleaned, then soaked for bottle.
several days in HNO3 (1 + 19), and rinsed thoroughly with
water. 25.9 Tellurium, Standard Stock Solution (1 mL = 1 mg
Tellurium)—Transfer a 0.100 g sample of tellurium metal
24.4 Plastic Containers—Plastic storage containers shall be
(purity, 99.9 % minimum), weighed to the nearest 0.1 mg, to a
of polytetrafluoroethylene (PTFE).
100-mL beaker. Proceed as directed in 25.2.1.
25. Reagents 25.10 Thallium, Standard Stock Solution (1 mL = 1 mg
25.1 Antimony, Standard Stock Solution (1 mL = 1 mg Thallium)—Transfer a 0.112-g sample of thallium (III) oxide
Antimony)—Transfer 0.274 g of potassium antimonyl tartrate (Tl2O3) (purity, 99.9 % minimum), weighed to the nearest 0.1
[K(SbO)C4H4O6·1⁄2 H2O] (purity, 99.9 % minimum), weighed mg, to a 100-mL beaker. Add 10 mL of HNO3 and heat to
exactly, to a 100-mL volumetric flask, dissolve in water, dilute dissolve. The same reagent lot of HNO3 shall be used through-
to volume, and mix. Do not use a solution that has stood for out the procedure. If high blanks are obtained, the HNO3 must
more than one day. be redistilled and the entire procedure repeated. Cool and
transfer to a 100-mL volumetric flask, dilute to volume, and
NOTE 4—The antimony concentrations in the more dilute, acidified mix. Store in a glass or PTFE container.
solutions prepared from this solution are stable.
25.11 Tin, Standard Stock Solution (1 mL = 1 mg Tin)—
25.2 Arsenic, Standard Stock Solution (1 mL = 1 mg
Transfer a 0.250-g sample of tin metal (purity, 99.9 %
Arsenic)—Transfer a 0.100-g sample of arsenic metal (purity,
minimum), weighed to the nearest 0.1 mg, to a 100-mL
99.9 % min), weighed to the nearest 0.1 mg, to a 100-mL
poly(tetrafluoroethylene) beaker. Add 7.5 mL of a mixture of
beaker.
equal parts of HF, HNO3, and water. The same reagent lot of
25.2.1 Add 10 mL of HNO3 (1 + 1) and heat until dissolu-
HNO3 shall be used throughout the procedure. If high blanks
tion is complete. Boil gently to expel oxides of nitrogen and
are obtained, the HNO3 must be redistilled and the entire
cool. Transfer to a 100-mL volumetric flask containing 10 mL
procedure repeated. Heat until dissolved. Boil gently to expel
of HNO3 (1 + 1), dilute to volume with water, and mix. Store
oxides of nitrogen. Cool and transfer to a 250-mL PTFE
in a glass or PTFE container.
volumetric flask. Dilute to volume and mix. Store in a PTFE
25.2.2 The same reagent lot of HNO3 shall be used through-
container.
out the procedure. If high blanks are obtained, the HNO3 must
be redistilled and the entire procedure repeated. If it is 25.12 Working Solutions:
impossible to use the same batch of HNO3, a second reagent 25.12.1 Mixed Analyte Standard Solution A (1 mL = 1 µg of
blank must be prepared using the same high-purity nickel Arsenic, Bismuth, Lead, Antimony, Selenium, Tin, Tellurium,
metal. This blank is then compared with the standard zero and Thallium)—Using a pipet, transfer 10.0 mL of each of the
calibration solution and an appropriate correction made, if standard stock solutions (arsenic, bismuth, lead, antimony,
significant. selenium, tin, tellurium, and thallium) to a 1-L volumetric flask

7
 E1587 − 17
containing 100 mL of HNO3 (1 + 1). Dilute to volume with 26.2.1 This set corresponds to (0, 0.0005, 0.001, 0.002,
water and mix. Using a pipet, transfer 10.0 mL of this solution 0.005, 0.010, 0.02, and 0.05) µg ⁄mL each of Silver and
to a 100-mL volumetric flask containing 10 mL of HNO3 Cadmium and is used for analyte levels from 0.01 µg ⁄g to
(1 + 1). Dilute to volume with water and mix. Store in a PTFE 5.0 µg ⁄g.
container. The same reagent lot of HNO3 shall be used 26.2.2 Using a buret, transfer 2.50 mL of nickel nitrate stock
throughout the procedure. If high blanks are obtained, the solution (25.12.3) to each of eight 10-mL volumetric flasks.
HNO3 must be redistilled and the entire procedure repeated. Add, using a buret graduated in 0.01-mL divisions, (0, 0.05,
25.12.2 Mixed Analyte Standard Solution B (1 mL = 0.1 µg 0.1, 0.2, 0.5, 1.0, 2.0, and 5.0) mL respectively of the mixed
of Silver and Cadmium)—Using a pipet, transfer 10.0 mL of analyte standard Solution B (25.12.2). Dilute to volume with
the silver and the cadmium stock solutions to a 1-L volumetric HNO3 (1 + 19) and mix.
flask containing 100 mL of HNO3 (1 + 1). Dilute to volume Aliquot, of Mixed Analyte Standard Analyte Concentration, µg/mL
with water and mix. Store in a glass container. Using a pipet, Solution B, mL Silver and Cadmium
transfer 10.0 mL of this solution to a 1-L volumetric flask 0 Blank
containing 100 mL of HNO3 (1 + 1). Dilute to volume with 0.05 0.0005
water and mix. Prepare this solution immediately before use. 0.10 0.0010
0.20 0.0020
25.12.3 Nickel Nitrate Solution (40 g Nickel/L)—Transfer a 0.50 0.0050
4.00-g sample of nickel metal (25.6), weighed to the nearest 1 1.0 0.010
2.0 0.020
mg, to a 400-mL beaker. Add 50 mL of water and 28 mL of 5.0 0.050
HNO3. The same reagent lot of HNO3 shall be used throughout
the procedure. If high blanks are obtained, the HNO3 must be 27. Procedure
redistilled and the entire procedure repeated. Do not stir or
apply heat until the vigorous reaction has ceased. Heat to 27.1 Preparation of Test Solution—Weigh, to the nearest
complete dissolution, then boil gently to expel oxides of 0.01 g, 0.9 g to 1.1 g of the test sample and transfer to a clean
nitrogen. Cool and filter through a low-porosity filter paper that unetched 100-mL beaker. Add 30 mL of water and 12 mL of
has been pre-washed with HNO3 (1 + 1). Recycle the filtrate HNO3 and allow to dissolve. Heat to complete dissolution, boil
through the filter paper to collect the fine carbon particles gently to expel oxides of nitrogen, cool, and transfer to a
which may have escaped the first filtration. Collect the filtrate 100-mL volumetric flask. Dilute to volume with water and mix.
in a 100-mL volumetric flask. Wash the filter with water, also 27.1.1 If inhomogeneity is suspected in the test sample, or if
collecting the washings, and dilute to volume with water and the sample pieces are relatively large, a larger sample mass
mix. should be used to prepare the test solution. Under such
circumstances a sample mass of 10 g in a final volume of
26. Calibration Solutions 1000 mL is recommended. The amount of HNO3 should be
increased in proportion. Even larger sample masses can be
26.1 Set A: used, with greater amounts of HNO3, to prepare a more
26.1.1 This set corresponds to (0, 0.005, 0.010, 0.02, 0.05, concentrated nickel test solution. However, this must then be
0.07, 0.1, 0.15, 0.20, 0.25, and 0.30) µg ⁄mL each of arsenic, diluted to give a test portion containing 10 g ⁄L nickel to match
bismuth, lead, antimony, selenium, tin, tellurium, and thallium, the calibration solutions.
respectively, and is used for analyte levels from 0.5 µg ⁄g to NOTE 5—The life of the graphite furnace tubes may be extended by
30.0 µg ⁄g. using 5 mL of HNO3 rather than 12 mL.
26.1.2 Using a buret, transfer 2.50 mL of the nickel nitrate 27.2 Reagent Blank Solution—The zero reference solutions
solution (25.12.3) to each of eleven 10-mL volumetric flasks. of the Sets A and B calibration solutions (26.1 and 26.2) serve
Add, using a buret graduated in 0.01-mL divisions, (0, 0.05, as reagent blanks since the same batch of HNO3 is used for
0.1, 0.2, 0.5, 0.7, 1.0, 1.5, 2.0, 2.5, and 3.0) mL, respectively, dissolution of both the nickel reference and test samples. If it
of mixed analyte standard Solution A (25.12.1). Dilute to is impossible to use the same batch of HNO3, a second reagent
volume with HNO3 (1 + 1) and mix. See the following table: blank must be prepared using the same high-purity nickel
Aliquot, of Mixed Analyte Standard Analyte Concentration, µg/mL metal. This blank is then compared with the standard zero
Solution A, mL Arsenic, Bismuth, Lead, Antimony,
Selenium, Tin, Tellurium, and calibration solution and an appropriate correction made, if
Thallium significant.
0 Blank 27.3 Instrumental Parameters:
0.05 0.005 27.3.1 The spectral lines specified in the following table are
0.1 0.010
0.2 0.02
to be used in the analysis. An alternate line for bismuth is
0.5 0.05 306.8 nm.
0.7 0.07
Spectral Lines
1.0 0.10
1.5 0.15
Element Silver Arsenic Bismuth Cadmium Lead
2.0 0.20
Wavelength, nm 328.1 193.7 223.1 228.8 283.3
2.5 0.25
3.0 0.30
Element Antimony Selenium Tin Tellurium Thallium
26.2 Set B: Wavelength, nm 217.6 196.0 286.3 214.3 276.8

8
 E1587 − 17
27.3.2 Set the required instrument parameters and align the TABLE 2 Statistical Information—Flame AAS Method,
graphite furnace atomizer in accordance with the manufactur- Procedure B
er’s recommendations. Optimum settings for the operating Repeatability Reproducibility
Test Material Mean, % Index, r Index, R
parameters vary from instrument to instrument. Scale expan- (Practice E1601) (Practice E1601)
sion may have to be used to obtain the required readability. Cobalt
Atomization temperatures of 2600 °C to 2700 °C are prefer- J61 0.010 0.0012 0.0017
able for a nickel matrix. The use of background compensation H79 0.106 0.0027 0.0076
S65 0.076 0.0047 0.0060
is essential. Copper
27.3.3 Determine the optimum graphite furnace atomizer J61 0.010 0.0006 0.0014
parameters for the particular type of atomizer and sample size H79 0.113 0.0008 0.0089
C1A 0.467 0.016 0.056
(5 µL to 25 µL) as recommended by the instrument manufac- Iron
turer or normal laboratory practice for each element to be J61 0.012 0.0013 0.0036
determined. H79 0.137 0.0024 0.010
Manganese
27.4 Spectrometry: J61 0.010 0.0005 0.0015
H79 0.164 0.0016 0.013
27.4.1 Ensure that the test solution and the Set A and Set B Zinc
calibration solutions are within 1 °C of the same temperature. J62 0.0026 0.0002 0.0004
27.4.2 Zero the instrument and set the base line on the J61 0.0068 0.0004 0.0009
recorder.
27.4.3 Check the zero stability and lack of spectral interfer-
ence within the atomization system by running the preset TABLE 3 Statistical Information—Graphite Furnace AAS Method
heating program for blank firing of the graphite atomizer. Repeatability Reproducibility
Test Mean,
Index, r Index, R
Repeat to ensure base line stability. Material %
(Practice E1601) (Practice E1601)
27.4.4 Inject, into the atomizer, the predetermined volume Silver (Ag)
(5 µL to 25 µL) of each of the test solutions for the element H79 0.00002 0.000010 0.000017
being determined. Atomize, and note the instrument response. P45 0.00044 0.00004 0.00011
P44 0.00076 0.00006 0.00024
Sort the test solutions into groups of three or four with similar Arsenic (As)
concentration levels of the analyte, starting with the lowest P45 0.00031 0.00005 0.000063
level. P44 0.00068 0.00005 0.00012
P46 0.00082 0.00016 0.00040
27.4.5 Select the appropriate calibration solutions, from H79 0.00164 0.00015 0.00026
Set A or Set B, to cover the range and bracket the concentration Bismuth (Bi)
levels in the test solutions. P45 0.00080 0.00011 0.00018
P46 0.00086 0.00012 0.00023
27.4.6 Inject and atomize the same predetermined volume P44 0.00115 0.00013 0.00019
(5 µL to 25 µL) of the calibration and test solutions in order of Cadmium (Cd)
increasing instrument response. Atomize each solution three P44 0.00006 0.000015 0.000017
P45 0.00014 0.00003 0.00007
times and, if the replication is good, record the readings for P46 0.00018 0.00002 0.000028
averaging. Check the instrument for memory effects, especially Lead (Pb)
at high-analyte levels, by running the blank firing program. P42 0.000026 0.000011 0.000036
S65 0.00015 0.00004 0.00005
Reset the zero base line if necessary. P45 0.00039 0.00005 0.00009
27.4.7 Evaluate the analyte contents in each group of test P46 0.00085 0.00009 0.00017
solutions based on the applicable calibration solutions as Antimony (Sb)
P44 0.00028 0.000036 0.00009
directed in Sections 28 and 29. P46 0.00085 0.00020 0.00059
S65 0.00120 0.00017 0.00031
28. Preparation of Calibration Curve Selenium (Se)
H79 0.00013 0.00003 0.00009
28.1 Calculate the average of the three instrument readings P46 0.00063 0.00016 0.00018
for each of the applicable calibration solutions. P45 0.00083 0.00015 0.00026
Tin (Sn)
28.2 Plot the average instrument readings versus the con- H79 0.00025 0.00007 0.000112
centrations of the analyte in the calibration solutions. Tellurium (Te)
H79 0.00048 0.000010 0.000027
28.3 For instruments that have automated calibration fea- P44 0.00020 0.00005 0.00010
tures and direct read-out in concentration plotting of calibration P46 0.00084 0.00016 0.00029
Thallium (Tl)
curves is not required. Follow the instrument operating instruc- S65 0.000065 0.000017 0.000023
tions for calibration and curvature correction procedures. P44 0.00020 0.00003 0.00008
P46 0.00086 0.00004 0.00019
28.4 If the high-purity nickel metal used to prepare the
calibration solution is contaminated by the element being
determined, graphic, or arithmetic methods must be used to
take this into account.
NOTE 6—In this test method, any effect of nonspecific absorption and the same lot of HNO3 is used for both sample and test solutions, the
light scatter is compensated for by matching the matrix of the calibration reagent blank is incorporated into the calibration curve. Thus, the
solutions with the test solutions and by background correction. Also, since calibration curve may not pass through the origin.

9
 E1587 − 17
29. Calculation by evaporation with HCl and formic acids, the sulfate is
29.1 Use the average of the three instrument readings reduced to hydrogen sulfide by hydriodic and hypophospho-
obtained for the test solution and the calibration curve prepared rous acids, evolved from the solution in an argon atmosphere,
in 28.2 to obtain the concentration of the analyte in the test and absorbed by a zinc amine complex solution. The absorbed
solution. sulfide sulfur is converted to methylene blue and the absor-
bance of the solution is measured at 665 nm and converted to
29.2 Calculate the mass fraction of the analyte, in micro-
micrograms of sulfur.
grams per gram, in the test sample as follows:
A 3B 34. Interferences
Analyte, µg/g 5 (3)
C 34.1 Elements normally present do not interfere.
where:
35. Hazards
A = analyte concentration found in the test solution, µg/mL,
35.1 There are toxicity risks related to the chemicals used in
B = volume of the test solution, mL, and the procedure and reasonable precautions must be taken.
C = mass of the test portion, g. Examine the glassware used in the distillation apparatus
carefully for cracks and check the tightness of joints.
30. Precision and Bias
30.1 Precision—Eleven laboratories in six countries partici- 36. Apparatus
pated in testing this method under the auspices of ISO/TC-155/ 36.1 Conventional Distillation Apparatus—Equipped with a
SC-3/WG-3 in the early 1980s and obtained the statistical data jacketed approximately 50-cm in length, Vigreux or packed
summarized in Table 3 as evaluated by ISO 5725 and equiva- reflux column for the purification of acids by distillation under
lent to Practice E1601. Precision may be judged by examina- atmospheric pressure, as shown in Fig. 1.
tion of these data. Six samples were analyzed to cover the
scope of this test method and of these, four were specially 36.2 Distillation Apparatus—For purification of the reduc-
prepared by melting and granulation, and two were commercial ing mixture (37.8), as shown in Fig. 2.
products. 36.3 Distillation Apparatus—For the generation and vola-
30.2 Bias—No information is currently available on the tilization of hydrogen sulfide from the test solution, as shown
accuracy of this test method due to the lack of appropriate
certified reference materials. The accuracy of a method may be
judged, however, by comparing accepted reference values with
the arithmetic average obtained by interlaboratory testing. The
user is cautioned that the results will be biased to the low side
if the nickel metal used for the preparation of the calibration
solutions does not meet the purity specifications given in this
test method and appropriate corrections are not made.
31. Keywords
31.1 antimony; arsenic; bismuth; cadmium; graphite fur-
nace atomic absorption spectrometry; lead; refined nickel;
selenium; silver; tellurium; thallium; tin
SULFUR BY THE METHYLENE BLUE
SPECTROPHOTOMETRIC METHOD AFTER
GENERATION OF HYDROGEN SULFIDE
32. Scope
32.1 This test method covers the determination of the sulfur
content of refined, wrought and cast nickel metal in the mass
fraction range from 0.0001 % to 0.002 %.
32.2 This international standard was developed in accor-
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
33. Summary of Test Method
33.1 The sample is dissolved in a nitric-chloric acid mixture
and the sulfur oxidized to sulfate ion. After removal of nitrates FIG. 1 Apparatus for Purification of Acids

10
 E1587 − 17

FIG. 3 Apparatus for Distillation of Hydrogen Sulfide

37.4 Purified Formic Acid—Distill reagent grade formic

FIG. 2 Apparatus for Purification of Reducing Mixture
acid using the apparatus in 36.1 and discard the first 10 % (v/v)
of the distillate. Collect the remaining distillate (except the last
few millilitres) in a thoroughly cleaned glass bottle.
37.5 Purified HCl—Distill HCl (3 + 2) using the apparatus
in Fig. 3. The double-surface condenser is preferred because of in 36.1 and discard the first 10 % (v/v) of the distillate. Collect
its superior cooling efficiency. the remaining distillate (except the last few millilitres) in a
36.4 Heating Mantle—The heating mantle should have a thoroughly cleaned glass bottle.
variable power setting such that the optimum temperature of 37.6 Purified HNO3—Distill HNO3 using the apparatus in
114 °C for the rapid reduction of sulfate to hydrogen sulfide 36.1 and discard the first 10 % (v/v) of the distillate. Collect the
can be maintained. remaining distillate (except for the last few millilitres) in a
36.5 Micropipettes—(0, 20, 50, and 100) µL. thoroughly cleaned glass bottle.
36.6 Glass storage containers shall be of borosilicate glass. 37.7 Nitric-Chloric Acid Mixture—Dissolve 3 g of potas-
sium chlorate (KClO3) in 30 mL of water and 100 mL of
37. Reagents purified HNO3 (37.6). Store in a glass bottle.
37.1 Argon Gas—(purity, 99.998 % min). 37.8 Reducing Mixture—Transfer 420 mL of hydriodic acid
(HI, 55 % minimum), 80 mL of hypophosphorous acid
37.2 Diamine Salt Solution—Dissolve 0.1 g of N,N- (H3PO2, 50 % minimum) and 70 g of sodium iodide (NaI) to
dimethyl-p-phenylenediamine hydrochloride or sulfate in the purifying apparatus (36.2). Attach the hydrogen sulfide trap
26 mL of HCl and dilute to 100 mL with water. Store in a cool containing 50 mL of the zinc acetate absorbing solution
dark place. Prepare fresh weekly. All acids used in the sample (37.10). Purge with argon at a flow rate of 200 mL ⁄min to
dissolution and the nitrate removal steps shall be purified by 300 mL ⁄min for 10 min to expel air from the system. Switch on
distillation to remove sulfur-containing species. Each reagent the electric heating mantle and heat the mixture at 113 °C to
shall contain less than 1 mg ⁄L of sulfur. To keep the reagent 115 °C for 4 h in a continuous flow of argon. During the
blank low, hydrochloric acid should contain less than purification of the reducing mixture, take care to ensure that the
0.05 mg ⁄L of sulfur. solution does not become overheated. Temperature monitoring
37.3 Ferric Chloride Solution—Dissolve 1.0 g of ferric with a thermometer is recommended. Allow the mixture to cool
chloride hexahydrate (FeCl3·6H2O) in 10 mL of HCl and while maintaining the argon flow. Transfer the cold reducing
40 mL of water. Dilute to 100 mL with water and store in a mixture, without delay, to a brown glass bottle. Stopper and
glass bottle. store in a cool dark place.

11
 E1587 − 17
37.9 Standard Sulfur Solution (10 mL = 1 mg Sulfur)— 39.1.1 It is essential that all sample treatment be performed
Dissolve exactly 0.5435 g of potassium sulfate (K2SO4), pre- in a scrupulously clean laboratory atmosphere, that is, free
viously dried at 105 °C for 1 h, in water in a 1000-mL from sulfuric acid fumes and any vapors or dust containing
volumetric flask. Dilute to volume with water and mix. sulfur species. Dissolution of the test sample in the three-neck
37.10 Zinc Acetate Absorbing Solution—Dissolve 5 g of flask, rather than a beaker, reduces the chance of contamina-
zinc acetate dihydrate [Zn(CH3COO)2·2H2O] and 70 g of tion.
ammonium chloride (NH4Cl) in about 350 mL of water. Add 39.1.2 Weigh 1.0 g of the test sample to the nearest 0.01 g,
7.5 g of NaOH, stir to dissolve, and dilute to 500 mL with and transfer to a 100-mL or 250-mL three-neck round-bottom
water. Store in a glass bottle. flask. Add 10 mL of nitric/chloric acid mixture and allow the
reaction to subside. Using low heat, carefully evaporate the
38. Calibration solution to a viscous syrup.
39.1.3 Add 10 mL of purified HCl (37.5) and heat to
38.1 Evolution of Hydrogen Sulfide:
dissolve the residue. Add 2 mL of purified formic acid (37.4)
38.1.1 To the cold, sulfur-free reducing mixture in a three-
and evaporate to dryness. Dissolve the dry residue in 10 mL of
neck flask from the blank (39.4), add, from a micro-pipette,
purified HCl and 0.5 mL of purified formic acid. Heat and
10 µL (1 µg S) of standard sulfur solution (37.9). Proceed as
digest for a few minutes on the hot plate to complete
directed in 39.2 and 39.3.
dissolution, and cool. If brown fumes appear during the final
38.1.2 Continue with additions, in order, of 20 µL, 50 µL,
dissolution, evaporate to dryness again and dissolve the residue
and 100 µL (2 µg, 5 µg, and 10 µg S) of standard sulfur solution
in purified HCl and formic acids.
(37.9), to the same sulfur-free reducing mixture as in 38.1.1.
Proceed after each addition as directed in 39.2 and 39.3. NOTE 7—The three-neck flask may be held in a cylindrical metal holder
Throughout the hydrogen sulfide evolution sequence for the for heating on a hot plate. A sand bath on a hot plate may also be used.
Alternatively, the flask may be suspended in a low-form beaker of suitable
calibration points there is no need to replace either the reducing size.
mixture or the acid trap solution.
39.2 Hydrogen Sulfide Evolution—Attach the three-neck
38.2 Methylene Blue Development—Introduce 3.0 mL of the flask to the distillation apparatus (36.3). Place 3 mL of purified
diamine salt solution (37.2) into the sulfide trap by means of HCl (1 + 4) into the acid trap, and 5.0 mL of zinc acetate
the gas inlet. Immediately follow with the addition of 0.5 mL solution (37.10) into the hydrogen sulfide trap. Add 30 mL of
of ferric chloride solution (37.3) and mix gently. Rinse the the reducing mixture (37.8) to the sample solution by means of
inside and outside of the gas inlet tube with a small quantity of the stoppered neck. Replace the stopper. Ensure that all joints
water. Mix the solution and transfer it to a 25-mL volumetric are secure and pass a flow of argon through the apparatus at a
flask. Wash the trap with water and add the washings to the rate of 30 mL ⁄min. After approximately 2 min, switch on the
flask. Dilute to volume with water, mix, and allow the solution heating mantle and continue heating at 114 °C for 30 min.
to stand for at least 30 min before measurement. Once fully Remove the sulfide trap and switch off the heating mantle.
developed, the methylene blue coloration is stable for at least Continue the flow of argon until the apparatus is cool.
24 h. 39.2.1 Chemically, the reduction of sulfate sulfur to hydro-
38.3 Spectrophotometric Measurement—Measure the absor- gen sulfide is a difficult reaction, and to ensure complete sulfur
bance of the solution in 1-cm or 2-cm cells, using water as the recovery the reaction conditions must be closely controlled.
reference, at a wavelength of 665 nm with a spectrophotom- The optimum reducing temperature is 114 °C to 116 °C. If the
eter. reducing solution is diluted excessively by the sample solution,
38.4 Calibration Curve—Plot the absorbance readings of the boiling point is decreased and the reduction kinetics are
the solutions obtained in 38.1.1 and 38.1.2 against micrograms slowed appreciably. For this reason, take care in 39.1.2 to
of sulfur present in the solutions. The line need not pass ensure that the final sample solution is approximately 10 mL.
through the origin as the absorbing solution usually shows a At temperatures above 120 °C the acid mixture shows signs of
slight background absorption upon addition of the diamine salt decomposition of hypophosphorous acid and formation of
and ferric chloride. phosphine.
39.3 Methylene Blue Development and
39. Procedure Spectrophotometry—Proceed as directed in 38.2 and 38.3.
39.1 Dissolution of Sample: 39.4 Reagent Blank—Proceed as directed in 39.1 to 39.3 but
omit the test sample. Allow the now sulfur-free reducing
solution to cool in a flow of argon and use it in the calibration
TABLE 4 Statistical Information—Sulfur by Distillation/Methylene (38.1).
Blue Method
Repeatability Reproducibility 40. Calculation
Test Material Mean, µg/g Index, r Index, R
(Practice E1601) (Practice E1601) 40.1 Convert the absorbance reading obtained for the
C-21 0.77 0.19 0.26 samples and blank into micrograms of sulfur using the cali-
C-22 3.30 0.33 0.67 bration graph (38.4).
C-23 13.10 0.68 3.90
40.2 Calculate the sulfur content of the sample as follows:

12
 E1587 − 17
A2B the auspices of ISO/TC-155/SC-4/WG-1 involving three labo-
Sulfur, % 5 3 1024 (4)
C ratories in three countries. Three samples were analyzed. The
statistical data obtained as evaluated by ISO 5725 and equiva-
where:
lent to Practice E1601 are summarized in Table 4. The
A = mass of sulfur in the test sample, µg, precision of this test method may be judged by examination of
B = mass of sulfur in the blank, µg, and these results.
C = mass of the test portion, g.
40.3 For a meaningful result, A must be greater than or 41.2 Bias—The bias of this test method could not be
equal to two times B. If A is less than 2B, the reagent blank evaluated because adequate certified reference materials were
must be improved by additional purification of the reagents unavailable at the time of testing. The user is cautioned to
used. Another possible source for high blanks can be the verify by the use of certified reference materials, if available,
laboratory environment. A blank value of 0.5 µg of sulfur has that the bias of this test method is adequate for the contem-
been found to be attainable and is acceptable. plated use.

41. Precision and Bias 42. Keywords

41.1 Precision—This test method was subjected to a very 42.1 hydrogen sulfide; methylene blue; refined nickel; spec-
limited interlaboratory test program in the early 1980s under trophotometry; sulfur

ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned
in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk
of infringement of such rights, are entirely their own responsibility.

This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and
if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards
and should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the
responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should
make your views known to the ASTM Committee on Standards, at the address shown below.

This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,
United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above
address or at 610-832-9585 (phone), 610-832-9555 (fax), or service@astm.org (e-mail); or through the ASTM website
(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222
Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http://www.copyright.com/

13