ASTM D4655-95(2023)

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: D4655 − 95 (Reapproved 2023)
Standard Test Methods for
Sulfates in Leather (Total, Neutral, and Combined Acid)
This standard is issued under the fixed designation D4655; 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 4.3 Crucible, Gooch, with porous porcelain filter (optional).
1.1 These test methods are intended for use in determining
5. Reagents
the total, neutral, and combined acid sulfate in mineral-tanned
5.1 Ammonium Hydroxide Solution, (0.1 N)—7 mL/L re-
leather.
agent grade concentrate NH OH. Optional: Potassium dihydro-
1.2 The values stated in SI units are to be regarded as
gen phosphate, 0.1 molar solution (13.6 g/L KH PO ) or
2 4
standard. No other units of measurement are included in this
sodium dihydrogen phosphate, 0.1 molar solution (13.8 g/ L
standard.
NaH PO -H O).
2 4 2
1.3 This standard does not purport to address all of the
5.2 Hydrochloric Acid Solution, (1.5 N)—125 mL/L reagent
safety concerns, if any, associated with its use. It is the
grade concentrate hydrochloric acid.
responsibility of the user of this standard to establish appro-
5.3 Barium Chloride Solution—(BaCl ·2H O), 1 %.
priate safety, health, and environmental practices and deter- 2 2
mine the applicability of regulatory limitations prior to use.
5.4 Sodium Hydroxide Solution, 0.01 N, 0.4 g/L.
1.4 This international standard was developed in accor-
5.5 Mixed Indicator, consisting of 60 mL of a 0.1 % solution
dance with internationally recognized principles on standard-
of methyl red and 40 mL of a 0.1 % solution of methylene blue,
ization established in the Decision on Principles for the
both in 95 % alcohol.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
6. Sampling, Test Specimens, and Test Units
Barriers to Trade (TBT) Committee.
6.1 The specimen for each determination shall consist of 1 g
2. Referenced Documents
leather from the composite sample (See Practice D2813).
2.1 ASTM Standards: 6.2 Two specimens from the composite sample shall be
D2813 Practice for Sampling Leather for Physical and
tested for each determination.
Chemical Tests
7. Procedure
D4654 Test Method for Sulfate Basicity in Leather
7.1 Total Sulfates—Weigh the specimen to the nearest mil-
3. Significance and Use
ligram and record the value as W . Transfer the specimen to a
3.1 These test methods are used to determine the basicity of
250 mL volumetric flask and add 200 mL of 0.1 N ammonium
leather when used in accordance with Test Method D4654.
hydroxide or 0.1 molar potassium or sodium dihydrogen
phosphate solution. Immerse the flask up to the neck in a bath
4. Apparatus
of boiling water. Thoroughly wet all products by swirling
4.1 Volumetric Flask, 250 mL.
occasionally. After 2 h cool the flask to room temperature, and
make up to volume with distilled water, shake, and without
4.2 Filter paper, ashless, fine grained and porcelain crucible.
delay filter through a folded filter paper. Discard the first 20 mL
1 to 25 mL of the filtrate. Pipette 200 mL of the filtrate into a
These test methods are under the jurisdiction of ASTM Committee D31 on
Leather and are the direct responsibility of Subcommittee D31.06 on Chemical
600 mL beaker and add about 20 mL of 1.5 N hydrochloric
Analysis. This test method was developed in cooperation with the American Leather
acid. Heat the solution to boiling and while boiling and stirring
Chemists Assn. (Method D20–1956).
the solution, add 20 mL of a 1 % solution of barium chloride
Current edition approved Sept. 1, 2023. Published September 2023. Originally
dropwise. Keep the covered beaker in a warm place at least for
approved in 1987. Last previous edition approved in 2017 as D4655 – 95 (2017).
DOI: 10.1520/D4655-95R23.
2 h and preferably overnight.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
7.1.1 Filter the precipitate through a fine grained ashless
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
filter paper and wash with hot water until free from chloride. A
Standards volume informat
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