ASTM E223-23e1

Standard Test Methods for Analysis of Sulfuric Acid

SIGNIFICANCE AND USE
3.1 These test methods provide for the classification of various grades of sulfuric acid and for the determination of various impurities. Acid strength and impurity levels are important factors in many uses of sulfuric acid.
SCOPE
1.1 These test methods cover the analysis of sulfuric acid.  
1.2 The following applies for the purposes of determining the conformance of the test results using this test method to applicable specifications, results shall be rounded off in accordance with the rounding-off method of Practice E29.  
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.  
1.4 The analytical procedures appear in the following order:    
Sections  
Total Acidity  
8 to 16  
Baumé Gravity  
17 to 26  
Nonvolatile Matter  
27 to 33  
Iron  
34 to 43  
Sulfur Dioxide  
44 to 51  
Arsenic  
52 to 61  
1.5 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. Consult current OSHA regulations, suppliers’ Safety Data Sheets, and local regulations for all materials used in this specification. Specific hazards statements are given in Section 5.  
1.6 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.

General Information

• Status: Published
• Publication Date: 31-Mar-2023
• ICS: 71.060.30 - Acids
• Technical Committee: D16 - Aromatic, Industrial, Specialty and Related Chemicals
• Drafting Committee: D16.10 - Acids

Relations

• Refers: ASTM E100-19 - Standard Specification for ASTM Hydrometers
• Effective Date: 01-May-2019
• Refers: ASTM D6809-02(2016) - Standard Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related Materials
• Effective Date: 01-Nov-2016
• Refers: ASTM E100-15a - Standard Specification for ASTM Hydrometers
• Effective Date: 01-Dec-2015
• Refers: ASTM E100-15 - Standard Specification for ASTM Hydrometers
• Effective Date: 01-Aug-2015
• Refers: ASTM E100-14 - Standard Specification for ASTM Hydrometers
• Effective Date: 01-May-2014
• Refers: ASTM E1-13 - Standard Specification for ASTM Liquid-in-Glass Thermometers
• Effective Date: 01-May-2013
• Refers: ASTM E100-10 - Standard Specification for ASTM Hydrometers
• Effective Date: 01-Nov-2010
• Refers: ASTM E29-08 - Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
• Effective Date: 01-Oct-2008
• Refers: ASTM E1-07 - Standard Specification for ASTM Liquid-in-Glass Thermometers
• Effective Date: 01-Nov-2007
• Refers: ASTM D6809-02(2007) - Standard Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related Materials
• Effective Date: 01-Jun-2007
• Refers: ASTM E29-06b - Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
• Effective Date: 15-Nov-2006
• Refers: ASTM E29-06a - Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
• Effective Date: 15-Sep-2006
• Refers: ASTM E29-06 - Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
• Effective Date: 01-May-2006
• Refers: ASTM D1193-06 - Standard Specification for Reagent Water
• Effective Date: 01-Mar-2006
• Refers: ASTM E1-05 - Standard Specification for ASTM Liquid-in-Glass Thermometers
• Effective Date: 01-Nov-2005

Overview

ASTM E223-23e1 - Standard Test Methods for Analysis of Sulfuric Acid establishes reliable procedures for assessing the quality, classification, and impurity content of sulfuric acid across multiple industrial applications. Developed by ASTM, these standardized test methods enable manufacturers, laboratories, and users to evaluate sulfuric acid strength and detect impurities with consistent accuracy, supporting quality control, regulatory compliance, and process optimization. The standard addresses various grades of sulfuric acid and their specific purity levels, ensuring the safe and efficient use of this widely employed industrial chemical.

Key Topics

The standard encompasses detailed analytical methods essential for sulfuric acid analysis:

• Total Acidity: Determines the precise acid content in sulfuric acid samples, crucial for formulation and process control.
• Baumé Gravity: Measures density, which is used for grade classification and concentration estimation.
• Nonvolatile Matter: Quantifies residual materials that do not evaporate, indicating potential contaminants or by-products.
• Iron Content: Assesses iron levels, which can affect both product performance and downstream processes.
• Sulfur Dioxide Content: Identifies free SO₂ in acid, important for industries where purity or reactivity could be influenced.
• Arsenic Determination: Ensures that arsenic concentrations remain within safe and regulated limits.

Testing is performed according to specified procedures, with safety, health, and environmental precautions recommended during all handling and analysis activities.

Applications

ASTM E223-23e1 is employed extensively in sectors where sulfuric acid quality and consistency directly impact product output and regulatory compliance:

• Chemical Manufacturing: Controls acid strength for reactions, catalysts, and chemical synthesis.
• Petroleum Refining: Checks for contaminants that can poison catalysts during alkylation and refining.
• Fertilizer Production: Ensures the purity of acid used in the production of phosphates and other agrochemicals.
• Metals Processing: Monitors purity for pickling and etching baths, protecting surface quality during metal treatment.
• Batteries and Energy Storage: Maintains reliable acid specifications for lead-acid batteries and related technologies.
• Environmental Compliance: Supports accurate reporting and regulatory submissions regarding impurities such as arsenic and iron.

Analytical results can influence procurement decisions, process control strategies, and documentation required for quality certifications.

Related Standards

Implementing ASTM E223-23e1 alongside other referenced standards ensures comprehensive quality control and consistent results:

• ASTM D1193: Specification for reagent water, vital for ensuring purity in all analytical procedures.
• ASTM E1: Specification for ASTM liquid-in-glass thermometers, ensuring accurate temperature measurements.
• ASTM E29: Practice for using significant digits in test data to determine conformance with specifications.
• ASTM E100: Specification for hydrometers, supporting accurate Baumé gravity determinations.
• ASTM E60: Practice for analysis of metals by spectrophotometry, relevant for iron and arsenic testing.
• ASTM E200, E300: Standards covering the preparation of chemical solutions and sampling of chemicals.

Using these standards in sequence or combination helps laboratories provide conformance to applicable sulfuric acid specifications and regulatory requirements.

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Keywords: ASTM E223-23e1, sulfuric acid analysis, sulfuric acid test methods, sulfuric acid impurities, total acidity, Baumé gravity, nonvolatile matter, industrial acid quality, chemical analysis standard, ASTM sulfuric acid, quality control, regulatory compliance, laboratory methods, iron in sulfuric acid, arsenic determination, sulfur dioxide testing.

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.
´1
Designation: E223 − 23
Standard Test Methods for
Analysis of Sulfuric Acid
This standard is issued under the fixed designation E223; 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.
ε NOTE—Editorial corrections were made to Equation 8 in May 2023.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 These test methods cover the analysis of sulfuric acid.
2. Referenced Documents
1.2 The following applies for the purposes of determining
the conformance of the test results using this test method to
2.1 ASTM Standards:
applicable specifications, results shall be rounded off in accor-
D1193 Specification for Reagent Water
dance with the rounding-off method of Practice E29.
D6809 Guide for Quality Control and Quality Assurance
Procedures for Aromatic Hydrocarbons and Related Ma-
1.3 The values stated in SI units are to be regarded as
terials
standard. The values given in parentheses are for information
E1 Specification for ASTM Liquid-in-Glass Thermometers
only.
E29 Practice for Using Significant Digits in Test Data to
1.4 The analytical procedures appear in the following order:
Determine Conformance with Specifications
Sections
E60 Practice for Analysis of Metals, Ores, and Related
Total Acidity 8 to 16
Materials by Spectrophotometry
Baumé Gravity 17 to 26
Nonvolatile Matter 27 to 33
E100 Specification for ASTM Hydrometers
Iron 34 to 43
E180 Practice for Determining the Precision of ASTM
Sulfur Dioxide 44 to 51
Methods for Analysis and Testing of Industrial and Spe-
Arsenic 52 to 61
cialty Chemicals (Withdrawn 2009)
1.5 This standard does not purport to address all of the
E200 Practice for Preparation, Standardization, and Storage
safety concerns, if any, associated with its use. It is the
of Standard and Reagent Solutions for Chemical Analysis
responsibility of the user of this standard to establish appro-
E300 Practice for Sampling Industrial Chemicals
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
3. Significance and Use
Consult current OSHA regulations, suppliers’ Safety Data
3.1 These test methods provide for the classification of
Sheets, and local regulations for all materials used in this
various grades of sulfuric acid and for the determination of
specification. Specific hazards statements are given in Section
various impurities. Acid strength and impurity levels are
5.
important factors in many uses of sulfuric acid.
1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4. Purity of Reagents
ization established in the Decision on Principles for the
4.1 Purity of Reagents—Reagent grade chemicals shall be
Development of International Standards, Guides and Recom-
used in all tests. Unless otherwise indicated, it is intended that
1 2
These test methods are under the jurisdiction of ASTM Committee D16 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Aromatic, Industrial, Specialty and Related Chemicals and are the direct responsi- contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
bility of Subcommittee D16.10 on Acids. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved April 1, 2023. Published April 2023. Originally the ASTM website.
approved in 1965. Last previous edition approved in 2016 as E223 – 16. DOI: The last approved version of this historical standard is referenced on
10.1520/E0223-23E01. www.astm.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
E223 − 23
all reagents shall conform to the specifications of the Commit- methods are given for weighing the sample, namely, the Dely
tee on Analytical Reagents of the American Chemical Society, tube and the snake tube test methods.
where such specifications are available. Other grades may be
9. Summary of Test Method
used, provided it is first ascertained that the reagent is of
sufficiently high purity to permit its use without lessening the
9.1 A weighed sample of acid is diluted in water and titrated
accuracy of the determination.
with standardized 0.5 meq/mL(N) sodium hydroxide solution,
using phenolphthalein as the indicator.
4.2 Purity of Water—Unless otherwise indicated, references
to water shall be understood to mean Type I or Type II reagent
10. Interferences
water conforming to Specification D1193.
10.1 Acids other than sulfuric and compounds that consume
5. Hazards
sodium hydroxide will affect the accuracy of this test method.
5.1 Consult current OSHA regulations, suppliers’ Safety
11. Apparatus
Data Sheets, and local regulations for all materials used in this
test method. Use of safety goggles and gloves highly recom- 11.1 Dely Tube (Fig. 1) or Snake Tube (Fig. 2).
mended.
5.2 Sulfuric acid is a strong corrosive acid and is dangerous
if improperly handled. Avoid any skin or eye contact.
5.3 Clean up all spills immediately by covering the spill
with vermiculite or some other inert absorbent material and
sweeping into a pan. Dispose of the absorbent by flooding with
water and discarding in a suitable container. Flush the area with
water.
6. Photometers and Photometric Practice
6.1 Photometers and the photometric practice used in these
test methods shall conform to Practice E60.
7. Sampling
7.1 Sample sulfuric acid in accordance with the appropriate
sections of Practice E300 for simple liquids.
7.2 The sample to be analyzed shall be considered to be that
sample in a single bottle submitted to the analytical laboratory.
7.3 The size of the sample shall be sufficient to perform all
analyses without the reuse of any portion of the sample.
TOTAL ACIDITY
8. Scope
8.1 This test method covers the determination of the total
FIG. 1 Dely Tube
acidity of 75 % to 99 % mass (m/m) sulfuric acid. Two test
11.2 Buret, 100 mL, Class A, bulb-type.
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
Standard-Grade Reference Materials, American Chemical Society, Washington,
12. Reagents
DC. For suggestions on the testing of reagents not listed by the American Chemical
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, 12.1 Phenolphthalein Indicator Solution (10 g/L)—Dissolve
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
1 g of phenolphthalein in 100 mL of ethanol (95 %), methanol,
copeial Convention, Inc. (USPC), Rockville, MD.
or isopropanol.
12.2 Sodium Hydroxide, Standard Solution (0.5 meq/
TABLE 1 Sample Size for Total Acidity
mL(N)—See Practice E200.
H SO , % mass (m/m) Sample Size, g
2 4
98 1.9 to 2.2
94 2.0 to 2.3
The sole source of supply of the Suitable Dely and snake tubes known to the
90 2.1 to 2.4
committee at this time is Corning Glass Works, Corning, NY. If you are aware of
85 2.2 to 2.6
alternative suppliers, please provide this information to ASTM International
80 2.3 to 2.7
Headquarters. Your comments will receive careful consideration at a meeting of the
77 2.4 to 2.8
75 2.5 to 2.9 responsible technical committee, which you may attend.
This reagent is also described in Practice E200.
´1
E223 − 23
Remove the tube and wash the outside free of acid. Swirl the
contents of the beaker gently while washing. Accumulate all
washings in the beaker and add 3 to 5 drops of phenolphthalein
indicator solution. Record the temperature of the 0.5 meq/
mL(N) NaOH solution, and then titrate the sample to a pink
end point. Record the titration to the nearest 0.02 mL.
NOTE 4—Do not introduce the water into the snake tube too rapidly, as
this will cause spattering.
14. Calculation
14.1 If necessary, correct the buret reading for calibration
errors and record the volume of titrant as V and the temperature
as t.
FIG. 2 Snake Tube
14.2 Correct the normality of the sodium hydroxide stan-
dard solution for any difference in temperature between time of
13. Procedure
standardization and time of use according to the following
13.1 Dely Tube Test Method—Invert the sample bottle
equation:
several times. (Hold the stopper in tight.) Insert the long arm of
N 5 N 10.00014 s 2 t (1)
~ !
s
a dry, weighed Dely tube and withdraw by suction a convenient
size sample depending upon the acid strength as given in Table where:
1 (Note 1). Invert the Dely tube and wipe the acid from the
N = normality meq/mL(N) of NaOH solution at temperature
long arm with disposable tissue several layers thick. Discard
t during use,
the tissue immediately to avoid burning the fingers. Reweigh to
N = normality meq/mL(N) of NaOH solution at temperature
s
the nearest 0.0001 g and record the weight of the sample.
s during standardization,
Incline the tube so that the acid runs back nearly to the bend of
s = temperature of NaOH solution during standardization,
the short arm. Attach the short arm to an elevated water
and
reservoir by means of a rubber tube closed near the lower end t = temperature of NaOH solution during analysis.
with a pinch clamp. Insert the long arm of the Dely tube into
14.3 Calculate the total acidity as % mass (m/m) of sulfuric
400 mL glass beaker containing approximately 100 mL of
acid as follows:
water. Open the pinch clamp and flush the sample into the
~VN × 0.04904!
beaker. Continue the flow of water until all acid is washed from
Sulfuric acid, % mass m/m 5 × 100 (2)
~ !
W
the Dely Tube (Note 2 and Note 3). Wash the long end of the
Dely tube, collecting the washings in the beaker. Add 3 to 5
where:
drops of phenolphthalein indicator solution. Record the tem-
V = corrected millilitre of NaOH solution required for
perature of the 0.5 meq/mL(N) NaOH solution, and then titrate
titration of the sample,
the sample to a pink end point. Record the titration to the
N = meq/mL(N) normality of the NaOH solution, and
nearest 0.02 mL.
W = grams of sample used.
NOTE 1—The Dely tube can be marked at points equivalent to weights
15. Report
given in Table 1.
NOTE 2—The presence of acid in the Dely tube may be detected by
15.1 Report the % mass (m/m) of sulfuric acid to the nearest
coloring the water in the reservoir with phenolphthalein indicator and the
0.01 % mass(m/m).
minimum amount of dilute NaOH solution that will produce a slight pink.
The water flowing through the tube is dicolorized as long as acid is
16. Precision and Bias
present, and the appearance of a pink color indicates the absence of acid.
NOTE 3—The acid and water are separated by a bubble of air.
16.1 The following criteria should be used for judging the
13.2 Snake Tube Test Method—Invert the sample bottle acceptability of results (see Note 5):
several times. (Hold the stopper in tight). Insert the capillary 16.1.1 Repeatability (Single Analyst)—The standard devia-
end of a dry, weighed snake tube and withdraw by suction a tion for a single determination has been estimated to be
convenient size sample depending upon the acid strength as 0.069 % mass (m/m) absolute at 56 df. The 95 % limit for the
given in Table 1. Invert the tube so that the double bend is in difference between two such runs is 0.19 % mass (m/m)
a horizontal position. Wipe the acid from the capillary with absolute.
disposable tissue several layers thick. Discard the tissue 16.1.2 Laboratory Precision (Within-Laboratory, Between-
immediately to avoid burning the fingers. Reweigh to the Days Variability—The standard deviation of results (each the
nearest 0.0001 g and record the weight of the sample. Sub- average of duplicates), obtained by the same analyst on
merge the capillary of the tube in approximately 100 mL of different days, has been estimated to be 0.104 % mass (m/m)
water contained in the 400 mL beaker. Force the weighed absolute at 28 df. The 95 % limit for the difference between
sample from the tube by a stream of water from a wash bottle two such averages is 0.29 % mass (m/m) absolute.
by placing the delivery tip in the exposed end of the snake tube 16.1.3 Reproducibility (Multilaboratory)—The standard de-
(Note 4). Wash the tube with 50 mL to 70 mL of water. viation of results (each the average of duplicates), obtained by
´1
E223 − 23
analysts in different laboratories, has been estimated to be 21.3 Cylinder, Hydrometer, glass, with or without lip, diam-
0.124 % mass (m/m) absolute at 7 df. The 95 % limit for the eter 38 mm to 40 mm, height 325 mm to 375 mm.
difference between two such averages is 0.35 % mass (m/m)
22. Temperature of Test
absolute.
22.1 Baumé gravity shall be determined at 15.5 °C 6 0.3 °C
NOTE 5—These precision estimates are based on an interlaboratory
(60 °F 6 0.5 °F).
study of analyses performed in 1963 on three samples containing
approximately 80 %, 90 %, and 95 % mass (m/m) sulfuric acid. One
23. Procedure
analyst in each of ten laboratories performed duplicate determinations and
repeated one day later, for a total of 120 determinations. Practice E180
23.1 Rinse a clean hydrometer cylinder with the sample to
was used in developing these precision estimates.
be tested, add the sample, and adjust the temperature to 15.5 °C
16.2 Since there is no accepted reference material for
6 0.3 °C (60 °F 6 0.5 °F). Place the cylinder in a vertical
determining the bias for measuring the total acidity of sulfuric position in a location free of air currents. Insert the hydrometer
acid, the bias of this test method has not been determined.
in the sample. Push it down about 3 mm below the level at
which it will float and release it. Read the hydrometer when it
BAUMÉ GRAVITY
has come to rest, floating freely, and the temperature is 15.5 °C
(60 °F). The correct reading is that point on the hydrometer
17. Scope
scale at which the surface of the liquid cuts the scale.
17.1 This test method covers the determination of the
Determine this point by placing the eye slightly below the level
Baumé gravity of concentrated sulfuric acid by means of a
of the liquid and slowly raising it until the surface, first seen as
glass hydrometer in the range from 57° Baumé to 66.2°
a distorted ellipse, appears to become a straight line cutting the
Baumé. The Baumé gravity is determined at 15.5 °C (60 °F).
hydrometer scale. Record as Baumé gravity.
This test method is not applicable to readings above 66.2
24. Calculation
Baumé gravity units.
24.1 Calculate the specific gravity for later calculations in
18. Definition
accordance with the following equation:
18.1 Baumé Gravity—a unit of density based on specific
gravity and defined by the following equation:
sp gr 5 (5)
145 2 Be´
Baume´ gravity 5 145 2 145/sp gr at 15.5/15.5°C 60/60°F (3)
@ # ~ !
25. Report
19. Summary of Test Method
25.1 Report the Baumé gravity to the nearest 0.01 unit.
19.1 A sample of sulfuric acid is placed in a hydrometer
26. Precision and Bias
cylinder and when the temperature is constant, the Baumé
gravity is read from the glass hydrometer.
26.1 The following criteria should be used for judging the
acceptability of results (see Note 6):
20. Significance and Use
26.1.1 Repeatability (Single Analyst)—The standard devia-
20.1 The Baumé gravity is used to classify various grades of tion for a single determination has been estimated to be 0.018
sulfuric acid. This test method is not applicable for accurate
unit absolute at 48 df. The 95 % limit for the difference
determinations of the concentration of sulfuric acid. between two such runs is 0.05 unit absolute.
26.1.2 Laboratory Precision (Within-Laboratory, Between-
21. Apparatus
Days Variability)—The standard deviation of results (each the
21.1 Hydrometer, streamline or torpedo design, precision average of duplicates), obtained by the same analyst on
grade for liquids heavier than water in ranges from 57° Bé to different days, has been estimated to be 0.016 unit absolute at
62° Bé and 63° Bé to 67° Bé. The total length shall be
24 df. The 95 % limit for the difference between two such
approximately 305 mm (12 in.) divided to 0.05° Bé over a averages is 0.045 unit absolute.
152 mm (6 in.) (approximate) scale and standardized at
26.1.3 Reproducibility (Multilaboratory)—The standard de-
15.5 °C ⁄15.5 °C (60 °F ⁄60 °F) with a tolerance of 0.05° Bé viation of results (each the average of duplicates), obtained by
throughout. The modulus is as follows:
analysts in different laboratories, has been estimated to be
0.063 unit absolute at 7 df. The 95 % limit for the difference
Be´ 5 145 2 @145/sp gr# at 15.5/15.5°C ~60/60°F! (4)
between two such averages is 0.18 unit absolute.
Each of the hydrometers shall show on the scale the
NOTE 6—These precision estimates are based on an interlaboratory
modulus.
study of analyses performed in 1963 on three samples having Baumé
gravities of approximately 61, 65, and 66 units. One analyst in each of
21.2 Thermometer, having a range from − 2 °C to + 80 °C
nine laboratories performed duplicate determinations and repeated one
(30 °F to 180 °F) and conforming to the requirements for
day later, for a total of 104 determinations. Practice E180 was used in
Thermometer 15C (15F) as prescribed in Specification E1.
developing these precision estimates.
26.2 Since there is no accepted reference material for
Supporting data have been filed at ASTM International Headquarters and may
determining the bias for measuring the Baumé gravity of
be obtained by requesting Research Report RR:E15-1047. Contact ASTM Customer
sulfuric acid, the bias of this test method has not been
Service at [e-mail].
See Specification E100. determined.
´1
E223 − 23
NONVOLATILE MATTER 31. Calculation
31.1 Calculate the % mass (m/m) of nonvolatile matter as
27. Scope
follows (Note 11):
27.1 This test method covers the gravimetric determination
RxD
~ !
of nonvolatile matter in sulfuric acid. The lower limit of
Nonvolatile matter, % mass ~m/m! 5 × 100 (6)
W
determination of nonvolatile matter is 0.001 % mass (m/m).
where:
28. Summary of Test Method
R = weight of evaporating dish and residue, g,
28.1 A weighed sample of acid is evaporated, ignited, and D = weight of evaporating dish, g, and
W = sample used, g.
the residue weighed.
NOTE 11—If this value is less than 0.0010 % mass (m/m), report as less
than 0.0010 % mass (m/m).
29. Apparatus
29.1 Evaporating Dish, platinum or high-silica glass,
32. Report
150 mL.
32.1 Report the percentage of nonvolatile matter to the
29.2 Muffle Furnace, maintained at 800 °C 6 25 °C
nearest 0.0001 % mass (m/m).
(1472 °F 6 45 °F).
29.3 Crucible Tongs.
33. Precision and Bias
33.1 The following criteria should be used for judging the
30. Procedure
acceptability of results (see Note 12):
30.1 Clean a platinum or a high-silica glass dish (Note 7 and
33.1.1 Repeatability (Single Analyst)—The standard devia-
Note 8) and ignite in a muffle furnace at 800 °C 6 25 °C
tion for a single determination has been estimated to be the
(1472 °F 6 45 °F) for at least 10 min. Cool in a desiccator to
value in Table 2 at the indicated degrees of freedom. The 95 %
room temperature and weigh the dish to the nearest 0.1 mg
limit for the difference between two such runs is given in Table
(Note 9).
2.
NOTE 7—New platinum or high-silica glass dishes should be boiled in
33.1.2 Laboratory Precision (Within-Laboratory, Between-
HCl (1 + 1) for 10 min, washed, and ignited in the muffle furnace for at
Days Variability)—The standard deviation of results (each the
least 1 h before their first use.
NOTE 8—High-silica glass dishes should be used only for low nonvola- average of duplicates), obtained by the same analyst on
tile material. The residue remaining from samples containing large
different days, has been estimated to be the value in Table 2 at
amounts of nonvolatile matter may fuse into the dish.
the indicated degrees of freedom. The 95 % limit for the
NOTE 9—High-silica glass dishes should be allowed to cool at least
difference between two such averages is given in Table 2.
45 min and platinum dishes at least 20 min before weighing.
33.1.3 Reproducibility (Multilaboratory)—The standard de-
30.2 Mix the sample by inverting the sample bottle repeat-
viation of results (each the average of duplicates), obtained by
edly until all solids are in suspension.
analysts in different laboratories, has been estimated to be the
NOTE 10—It is important that the sample be well mixed and that all
value given in Table 2 at the indicated degrees of freedom. The
solids are in homogeneous suspension so that a representative sample can
95 % limit for the difference between two such averages is
be obtained.
given in Table 2.
30.3 Transfer a weighed sample containing a minimum of
NOTE 12—These precision estimates are based on an interlaboratory
50 g, weighed to the nearest 0.1 g, or a weighed sample of
study of analyses performed in 1963 to 1964 on five samples containing
sufficient size to yield not less than 1 mg of residue, to the
approximately 0.003 %, 0.005 %, 0.010 %, 0.014 %, 0.024 %, and
evaporating dish and evaporate to dryness over a burner or hot
0.048 % mass (m/m) nonvolatile matter. One analyst in each of eight to
plate in a hood. After evaporation, ignite the sample in the
ten laboratories performed duplicate determinations and repeated one day
later. Practice E180 was used in developing these precision estimates.
muffle furnace for 10 min. Use crucible tongs in handling the
evaporating dish at all times.
33.2 Since there is no accepted reference material for
30.4 Allow the dish to cool to room temperature in a determining the bias for measuring the nonvolatile matter of
desiccator and rapidly weigh the sample dish to the nearest sulfuric acid, the bias of this test method has not been
0.1 mg. determined.
TABLE 2 Nonvolatile Matter Precision Values
Repeatability Laboratory Precision Reproducibility
NVM,% mass
Standard Degrees of Standard Degrees of Standard Degrees of
(m/m)
95 % Range 95 % Range 95 % Range
Deviation Freedom Deviation Freedom Deviation Freedom
0.003 0.0004 22 0.0010 0.0004 11 0.0010 0.0015 10 0.0040
0.004 0.0008 16 0.0023 0.0007 8 0.0019 0.0013 7 0.0036
0.01 to 0.024 0.0015 54 0.0042 0.0009 27 0.0024 0.0013 7 0.0036
0.048 0.0009 20 0.0025 0.0013 10 0.0036 0.0046 9 0.0130
´1
E223 − 23
IRON each flash add the following reagents in order, mixing after
addition of each: 20 mL of water, 1 mL of hydroxylamine
34. Scope
hydrochloride solution, 5 mL of 1,10-phenanthroline solution,
34.1 This test method describes the determination of iron in
and NH OH (1 + 1) as required to bring the pH to 3.5 to 4.0
sulfuric acid. The lower limit of determination of iron is (just alkaline to Congo red paper). Add 5 mL of ammonium
0.0001 % mass (m/m).
acetate solution, dilute to the mark with water, mix thoroughly,
and allow to stand approximately 15 min.
35. Summary of Test Method
39.2 Measure the absorbances of the solutions using a
35.1 The iron is reduced and determined colorimetrically
photometer with a wavelength setting of 510 nm or a filter
with 1,10-phenanthroline (ortho-phenanthroline), which forms
photometer equipped with a filter in the range from 500 nm to
an orange-red complex with ferrous iron. The intensity of the
525 nm, adjusting the photometer to read zero absorbance for
color so formed is measured in a photometer calibrated with
the reagent blank.
standard iron solutions.
39.3 Plot on coordinate paper the absorbances of the cali-
36. Interferences
bration solutions against milligrams of iron present per 100 mL
of solution.
36.1 It is beyond the scope of this test method to describe
procedures for overcoming all possible interferences that may
40. Procedure
be encountered. Chromium interferes if it is present in suffi-
cient quantity for the color of chromic ion to have a masking
40.1 Mix the sample by inverting the sample bottle until all
effect. Copper, antimony, cobalt, mercury (I), and tin (II, IV)
solids are in suspension (Note 10).
interfere in concentrations of 10 μg ⁄g to 50 μg/g (ppm).
40.2 Insert a 70 mm stem funnel in a 100 mL volumetric
Cadmium, mercury (II), zinc, and nickel may interfere, but can
flask and add 50 mL of water (Note 14). Remove the funnel
be overcome by the use of excess 1,10-phenanthroline reagent.
and slowly add, with continual swirling of the contents of the
flask, 1 g of sample weighed by difference to the nearest
37. Apparatus
0.001 g. Wash down the neck of the flask with approximately
37.1 Photometer—Any photoelectric spectrophotometer or
5 mL of water.
filter photometer that will measure th
...