ASTM E224-23

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E224 − 16 E224 − 23
Standard Test Methods for
Analysis of Hydrochloric Acid
This standard is issued under the fixed designation E224; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 These test methods cover the analysis of hydrochloric 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
Sulfated Ash 27 to 34
Iron 35 to 44
Color 45 to 52
Total Sulfur 53 to 59
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 and , 30.1, 39.7, and 48.4.
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.
2. Referenced Documents
2.1 ASTM Standards:
D1193 Specification for Reagent Water
D1209 Test Method for Color of Clear Liquids (Platinum-Cobalt Scale)
D6809 Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related Materials
These test methods are under the jurisdiction of ASTM Committee D16 on Aromatic, Industrial, Specialty and Related Chemicals and are the direct responsibility of
Subcommittee D16.10 on Acids.
Current edition approved April 1, 2016April 1, 2023. Published May 2016May 2023. Originally approved in 1965. Last previous edition approved in 20082016 as
E224 – 08.E224 – 16. DOI: 10.1520/E0224-16.10.1520/E0224-23.
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 Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*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
E224 − 23
E1 Specification for ASTM Liquid-in-Glass Thermometers
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E60 Practice for Analysis of Metals, Ores, and Related Materials by Spectrophotometry
E100 Specification for ASTM Hydrometers
E180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals
(Withdrawn 2009)
E200 Practice for Preparation, Standardization, and Storage of Standard and Reagent Solutions for Chemical Analysis
E300 Practice for Sampling Industrial Chemicals
3. Significance and Use
3.1 These test methods provide for the classification of various grades of hydrochloric acid and for the determination of various
impurities. Acid strength and impurity levels are important factors in many uses of hydrochloric acid.
4. Purity of Reagents
4.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high
purity to permit its use without lessening the accuracy of the determination.
4.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean Type III or Type IIIII reagent
water conforming to Specification D1193.
5. Hazards
5.1 Consult current OSHA regulations, suppliers’ Safety Data Sheets, and local regulations for all materials used in this test
method.
5.2 Hydrochloric acid is a corrosive acid and is dangerous if improperly handled. Avoid any skin contact. Use of safety goggles
and gloves highly recommended.
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 prescribed in these test methods shall conform to Practice E60.
7. Sampling
7.1 Sampling of hydrochloric acid is not within the scope of these testSample hydrochloric acid in accordance with the appropriate
sections of Practice E300 methods.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.
The last approved version of this historical standard is referenced on www.astm.org.
Reagent Chemicals, American Chemical Society Specifications,ACS Reagent Chemicals, Specifications and Procedures for Reagents and Standard-Grade Reference
Materials, American Chemical Society, Washington, 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, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USP),(USPC),
Rockville, MD.
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TOTAL ACIDITY
8. Scope
8.1 This test method covers the determination of the total acidity of 2727 % to 37 % mass (m/m) hydrochloric acid.
9. Summary of Test Method
9.1 A weighed sample of acid is diluted in water and titrated with standardized 0.5 meq/mL (N) sodium hydroxide solution, using
phenolphthalein as the indicator.
10. Interferences
10.1 Acids other than hydrochloric and compounds that consume sodium hydroxide will affect the accuracy of this test method.
11. Apparatus
11.1 Buret, 50-mL,50 mL, Class A.
11.2 Weighing Bottle, glass-stoppered, 50-mL.50 mL.
12. Reagents
12.1 Phenolphthalein Indicator, Solution (10 g/L)—Dissolve 1 g of phenolphthalein in 100 mL of ethanol (95 %), methanol, or
isopropanol.
12.2 Sodium Hydroxide, Standard Solution (0.5 meq/mL (N))—See Practice E200. Correct for differences in temperature in
accordance with the following formula:
N 5 N 10.00014 ~s 2 t! (1)
s
where:
N = normality meq/mL (N) of NaOH solution at temperature t,
N = normality meq/mL (N) of NaOH solution at temperature s during standardization,
s
s = temperature of NaOH solution during standardization, °C, and
t = temperature of NaOH solution during analysis,°C.
t = temperature of NaOH solution during analysis, °C.
13. Procedure
13.1 Transfer approximately 30 mL of water to a 50-mL50 mL glass-stoppered weighing bottle, stopper, and weigh to the nearest
0.1 mg. Rapidly add a convenient size sample, depending upon the acid strength as given in Table 1, stopper immediately, and
reweigh. Transfer the sample to a 400-mL400 mL beaker containing approximately 50 mL of water 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.
TABLE 1 Sample Size For Total Acidity
HCl, % mass (m/m) Sample Size, g
37 1.9 to 2.3
35 2.0 to 2.4
33 2.2 to 2.6
31 2.3 to 2.8
29 2.5 to 3.0
27 2.7 to 3.2
This reagent is also described in Practice E200.
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14. Calculation
14.1 Correct the buret reading for calibration errors, and record as V the corrected delivered volume at the recorded temperature.
14.2 Calculate the total acidity as % mass (m/m) of hydrochloric acid as follows:
VN ×0.03646
Hydrochloric acid,% mass m/m 5 ×100 (2)
~ ! S D
W
where:
V = corrected mL of NaOH solution required for titration of the sample,
N = normality meq/mL (N) of the NaOH solution, and
W = sample used, g.
15. Report
15.1 Report the % mass (m/m) of hydrochloric acid to the nearest 0.01 % mass (m/m).
16. Precision and Bias
16.1 The following criteria should be used for judging the acceptability of results (see Note 1):
16.1.1 Repeatability (Single Analyst)—The coefficient of variation for a single determination has been estimated to be 0.133 %
mass (m/m) relative at 50 df. The 95 % limit for the difference between two such runs is 0.37 % mass (m/m) relative.
16.1.2 Laboratory Precision (Within-Laboratory, Between-Days Variability)—The coefficient of variation of results (each the
average of duplicates), obtained by the same analyst on different days, has been estimated to be 0.170 % mass (m/m) relative at
25 df. The 95 % limit for the difference between two such averages is 0.48 % mass (m/m) relative.
16.1.3 Reproducibility (Multilaboratory)—The coefficient of variation of results (each the average of duplicates), obtained by
analysts in different laboratories, has been estimated to be 0.285 % mass (m/m) relative at 7 df. The 95 % limit for the difference
between two such averages is 0.80 % mass (m/m) relative.
NOTE 1—These precision estimates are based on an interlaboratory study of analyses performed in 1963 on three samples containing approximately 28,
31,28 %, 31 %, and 38 % mass (m/m) hydrochloric acid. One analyst in each of ten laboratories performed duplicate determinations and repeated one
day later, for a total of 120 determinations. Practice E180 was used in developing these precision estimates.
16.2 Bias—The bias of this test method has not been determined due to the unavailability of suitable reference materials.
BAUMÉ GRAVITY
17. Scope
17.1 This test method covers the determination of the Baumé gravity of hydrochloric acid by means of a glass hydrometer in the
range from 17.517.5° to 23° Baumé. The Baumé gravity is determined at 15.5°C (60°F).15.5 °C (60 °F).
18. Terminology
18.1 Definitions:
18.1.1 Baumé gravity—a unit of density based on specific gravity and defined by the following equation:
Baumégravity 5
145 2 @145 ⁄ ~sp gr 15.5 ⁄ 15.5 ° C ~60 ⁄ 60 ° F!!# (3)
Details of the interlaboratory study are available from ASTM International Headquarters. Request Research Report RR:E15-1046.
E224 − 23
19. Summary of Test Method
19.1 A sample of hydrochloric acid is placed in a hydrometer cylinder and when the temperature is constant, the Baumé gravity
is read from the glass hydrometer.
20. Significance and Use
20.1 The Baumé gravity is used to classify various grades of hydrochloric acid.
21. Apparatus
21.1 Hydrometer, streamline or torpedo design, precision grade, for liquids heavier than water in ranges from 17.5 to
23°Bé.17.5 °Bé to 23 °Bé. The total length shall be approximately 305 mm (12 in.) divided to 0.1°Bé0.1 °Bé over a 152-mm
(6-in.)152 mm (6 in.) (approximate) scale and standardized at 15.5/15.5°C (60/60°F)15.5/15.5 °C (60 ⁄60 °F) with a tolerance of
0.1°Bé0.1 °Bé throughout. The modulus is as follows:
Be´ 5 145 2 @145/sp gr 15.5/15.5°C~60/60°F!# (4)
Each of the hydrometers shall show on the scale the modulus (or formula).
21.2 Thermometer, having a range from − 2 to + 80°C (30 to 180°F)from − 2 °C to + 80 °C (30 °F to 180 °F) and conforming to
the requirements for Thermometer 15C (15F) in accordance with Specification E1.
21.3 Cylinder, Hydrometer, glass with or without lip, diameter 3838 mm to 40 mm, height 325325 mm to 375 mm.
22. Temperature of Test
22.1 Baumé gravity shall be determined at 15.5 6 0.3°C (60 6 0.5°F).15.5 °C 6 0.3 °C (60 °F 6 0.5 °F).
23. Procedure
23.1 Rinse a clean hydrometer cylinder with the sample to be tested, add the sample, and adjust the temperature to 15.5 6 0.3°C
(60 6 0.5°F).15.5 °C 6 0.3 °C (60 °F 6 0.5 °F). Place the cylinder in a vertical position in a location free of air currents. Insert
the hydrometer when it has come to rest, floating freely, and the temperature is 15.5°C (60°F).15.5 °C (60 °F). The correct reading
is that point of the hydrometer scale at which the surface of the liquid cuts the scale. Determine this point by placing the eye slightly
below the level of the liquid and slowly raising it until the surface, first seen as a distorted ellipse, appears to become a straight
line cutting the hydrometer scale.
24. Calculation
24.1 Calculate the specific gravity for use in the determination of iron using the following equation:
sp gr 5 (5)
~145 2 Be´ gravity!
25. Report
25.1 Report the Baumé gravity to the nearest 0.1 unit.
26. Precision and Bias
26.1 The following criteria should be used for judging the acceptability of results (see Note 2):
26.1.1 Repeatability (Single Analyst)—The standard deviation for a single determination has been estimated to be 0.048 unit
absolute at 48 df. The 95 % limit for the difference between two such runs is 0.1 unit absolute.
See Specification E100.
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26.1.2 Laboratory Precision (Within-Laboratory, Between-Days Variability)—The standard deviation of results (each the average
of duplicates), obtained by the same analyst on different days, has been estimated to be 0.046 unit absolute at 24 df. The 95 % limit
for the difference between two such averages is 0.1 unit absolute.
26.1.3 Reproducibility (Multilaboratory)—The standard deviation of results (each the average of duplicates), obtained by analysts
in different laboratories, has been estimated to be 0.084 unit absolute at 7 df. The 95 % limit for the difference between two such
averages is 0.2 unit absolute.
NOTE 2—These precision estimates are based on an interlaboratory study of analyses performed in 1963 on three samples having Baumé gravities of
approximately 18, 20, and 23 units. One analyst in each of nine laboratories performed duplicate determinations and repeated one day later, for a total
of 108 determinations. Practice E180 was used in developing these precision estimates.
26.2 Bias—The bias of this test method has not been determined due to the unavailability of suitable reference materials.
SULFATED ASH
27. Scope
27.1 This test method covers the gravimetric determination of material not volatile after treatment with sulfuric acid. The lower
limit of determination of sulfated ash is 0.001 % mass (m/m).
28. Summary of Test Method
28.1 A weighed sample of acid, to which sulfuric acid has been added, is evaporated, ignited, and the residue weighed.
29. Apparatus
29.1 Evaporating Dish, platinum or high-silica glass, 150-mL.150 mL.
29.2 Muffle Furnace, maintained at 800 6 25°C (1472 6 45°F).800 °C 6 25 °C (1472 °F 6 45 °F).
29.3 Crucible Tongs.
30. Reagent
30.1 Sulfuric Acid (1 + 1)—Add slowly with stirring 1one volume of concentrated sulfuric acid (H SO , sp gr 1.84) to 1one
2 4
volume of water. (Warning—Use goggles when preparing this solution.)
31. Procedure
31.1 Clean a platinum or a high-silica glass dish (see warning above and Note 3) and ignite in a muffle furnace at 800 6 25°C
(1472 6 45°F)800 °C 6 25 °C (1472 °F 6 45 °F) for at least 10 min. 10 min. Cool in a desiccator to room temperature and weigh
the dish to the nearest 0.1 mg (Note 5).
NOTE 3—New platinum or high-silica glass dishes should be boiled in hydrochloric acid (HCl, 1 + 1) for 10 min, washed, and ignited in the muffle furnace
for at least 1 h 1 h before their first use.
NOTE 4—High-silica glass dishes should be used only for low nonvolatile material. The residue remaining from samples containing large amounts of
nonvolatile matter may fuse into the dish.
NOTE 5—High-silica glass dishes should be allowed to cool at least 45 min and platinum dishes at least 20 min before weighing.
31.2 Mix the sample by inverting the sample bottle until all solids are in suspension.
31.3 Transfer a weighed sample containing a minimum of 50 g, weighed to the nearest 0.1 g, or a weighed sample of sufficient
size to yield not less than 1 mg of residue, to the evaporating dish, add 4 drops of H SO , evaporate almost to dryness on a steam
2 4
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bath, and then to dryness over a burner or hotplate in a hood. After evaporation, ignite the sample in the muffle furnace for 10 min.
Use crucible tongs in handling the evaporating dish at all times.
31.4 Allow the dish to cool to room temperature in a desiccator and rapidly weigh the sample dish to the nearest 0.1 mg.
32. Calculation
32.1 Calculate the % mass (m/m) of sulfated ash as follows (Note 6):
R 2 D
@ #
Sulfated ash, % mass m/m 5 ×100 (6)
~ !
W
where:
R = weight of evaporating dish and residue, g,
D = weight of evaporating dish, g, and
W = sample used, g.
NOTE 6—When this value is less than 0.0010 % mass (m/m), report as less than 0.0010 % mass (m/m).
33. Report
33.1 Report the % mass (m/m) of sulfated ash to the nearest 0.0001 % mass (m/m).
34. Precision and Bias
34.1 The following criteria should be used for judging the acceptability of results (see Note 7):
34.1.1 Repeatability (Single Analyst)—The standard deviation for a single determination has been estimated to be the value in
Table 2 at the indicated degrees of freedom. The 95 % limit for the difference between two such runs is given in Table 2.
34.1.2 Laboratory Precision (Within-Laboratory, Between-Days Variability)—The standard deviation of results (each the average
of duplicates), obtained by the same analyst on different days, has been estimated to be the amount in Table 2 at the indicated
degrees of freedom. The 95 % limit for the difference between two such averages is given in Table 2.
34.1.3 Reproducibility (Multilaboratory)—The standard deviation of results (each the average of duplicates), obtained by analysts
in different laboratories, has been estimated to be the amount in Table 2 at the indicated degrees of freedom. The 95 % limit for
the difference between two such averages is given in Table 2.
NOTE 7—The precision estimates in 34.1.1, 34.1.2, and 34.1.3 are based on an interlaboratory study of analyses performed in 1963–1964 on five samples
containing approximately 0.004, 0.014, 0.018, 0.035,0.004 %, 0.014 %, 0.018 %, 0.035 %, and 0.054 % mass (m/m) sulfated ash. One analyst in each
of eight to thirteen laboratories performed duplicate determinations and repeated one day later, for a total of 216 determinations. Practice E180 was used
in developing these precision estimates.
34.2 Bias—The bias of this test method has not been determined because of the lack of acceptable reference material.
IRON
35. Scope
35.1 This test method is a colorimetric estimation of iron in hydrochloric acid. The lower limit of determination of iron is
0.0001 % mass (m/m).
TABLE 2 Sulfated Ash Precision Values
Repeatability Laboratory Precision Reproducibility
Level,%
Standard Degrees of Standard Degrees of Standard Degrees of
mass (m/m) 95 % Limit 95 % Limit 95 % Limit
Deviation Freedom Deviation Freedom Deviation Freedom
0.005 0.0007 24 0.0020 0.0008 12 0.0022 0.0011 11 0.0031
0.015 0.0009 38 0.0024 0.0011 19 0.0032 0.0011 6 0.0032
0.050 0.0028 42 0.0080 0.0028 21 0.0078 0.0028 8 0.0078
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36. Summary of Test Method
36.1 The iron is reduced and determined colorimetrically with 1,10-phenanthroline (ortho-phenanthroline), which forms an
orange-red complex with ferrous iron. The intensity of the color is measured in a photometer calibrated against standard iron
solutions.
37. Interferences
37.1 It is beyond the scope of this test method to describe procedures for overcoming all possible interferences that may be
encountered. Chromium interferes if it is present in sufficient quantity for the color of chromic or chromate ion to have a masking
effect. Copper, antimony, cobalt, mercury (I), and tin (II, IV) interfere in concentrations of 1010 μg ⁄g to 50 μg/g (ppm). Cadmium,
mercury (II), zinc, and nickel complexes may interfere, but can be overcome by the use of excess of the 1,10-phenanthroline
reagent.
38. Apparatus
38.1 Photometer—Any photoelectric spectrophotometer or filter photometer that will measure the absorbance of the solutions in
the range from 500 to 525 nm.500 nm to 525 nm.
38.2 Absorption Cells, 2-cm2 cm light path.
NOTE 8—This procedure has been written for a cell having a 2-cm2 cm light path. Cells having ot
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