ASTM D2810-01

Standard Test Method for pH of Leather

SCOPE
1.1 This test method covers the determination of the pH of all types of leather. This method does not apply to wet blue.
1.2 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-May-2001
• ICS: 59.140.30 - Leather and furs
• Technical Committee: D31 - Leather
• Drafting Committee: D31.06 - Chemical Analysis

Relations

• Replaces: ASTM D2810-72(1996) - Standard Test Method for pH of Leather
• Effective Date: 10-May-2001
• Replaced By: ASTM D2810-07 - Standard Test Method for pH of Leather
• Effective Date: 01-Apr-2007

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D2810–01
Standard Test Method for
1
pH of Leather
This standard is issued under the fixed designation D 2810; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 4.2.3 Extract the weighed specimen with a fat solvent in a
Soxhlet apparatus for 5 h. Allow the specimen to air until all
1.1 This test method covers the determination of the pH of
solvent has evaporated; then proceed as outlined in Section 9.
all types of leather. This method does not apply to wet blue.
1.2 This standard does not purport to address all of the
5. Apparatus
safety concerns, if any, associated with its use. It is the
5.1 Electrometric pH Meter, either battery or line-operated,
responsibility of the user of this standard to establish appro-
with a glass electrode and calomel reference electrode. The
priate safety and health practices and determine the applica-
meter shall have a maximum scale division of 0.1 pH unit, and
bility of regulatory limitations prior to use.
shall have an accuracy of at least 0.1 pH unit and reproduc-
2. Terminology ibility of 0.05 pH unit.
2.1 Definition of Term Specific to this Standard:
NOTE 1—Sellers list reasonably priced models having an accuracy of
2.1.1 The pH of a solution has been defined as the negative 60.05, sensitive to 0.02 and with reproducibility to 0.02 pH units.
logarithm of the hydrogen ion activity. A solution of pH 7 is
5.2 Analytical Balance, sensitive to 0.01 g.
neutral at 24°C. Lower numbers indicate increasing acidity;
higher numbers, increasing alkalinity.
6. Reagents
6.1 Purity of Reagents—Reagent grade chemicals shall be
3. Significance and Use
used in all tests. Unless otherwise indicated, it is intended that
3.1 This test method is designed to measure the pH of a
all reagents shall conform to the specifications of the Commit-
distilled-water extract of leather. This is considered to be a
tee onAnalytical Reagents of theAmerican Chemical Society,
measure of the acidity or alkalinity of the leather. Excessive 3
where such specifications are available. Other grades may be
acidity or alkalinity may have a deleterious effect on the aging
used, provided it is first ascertained that the reagent is of
characteristics of leather.
sufficiently high purity to permit its use without lessening the
3.2 This test method is suitable for development, control,
accuracy of the determination.
and service evaluation of leather.
6.2 Purity of Water—Unless otherwise indicated, references
to water shall be understood to mean distilled water or water of
4. Interferences
equal purity. Distilled water shall have a pH value of not less
4.1 If the leather contains an excessive amount of fats or
than 5.5 nor more than 7.0 and shall give a residue of not more
greases or has been treated with a material to obtain water
than 0.5 mg, when 100 mL is evaporated and dried in a
repellency, the wettability and consequently the extractability
platinum dish.
may be affected.
4
6.3 Standard pH Solutions:
4.2 If the specimen is difficult or impossible to wet, it may
6.3.1 Alkaline Phosphate Buffer Solution (0.01 M trisodium
be treated by any of the following procedures:
phosphate, pH = 11.72 at 25°C)—Dissolve 1.42 g of anhy-
4.2.1 A vacuum may be used to effect wetting.
drous disodium hydrogen phosphate (Na HPO ) in 100 mL of
2 4
4.2.2 Mix with the required amount of water for 1 min in a
2
disintegrator.
3
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
1
ThistestmethodisunderthejurisdictionofASTMCommitteeD-31onLeather listed by the American Chemical Society, see Analar Standards for Laboratory
and is the direct responsibility of Subcommittee D31.06.01 on General Methods. Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
This test method was developed in cooperation with theAmerican Leather Chemists and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
Assn. (Standard Method B 20 – 1969). MD.
4
Current edition approved May 10, 2001. Published May 2001. Originally Buffer salts and solutions prepared in accordance with National Bureau of
published as D 2810 – 69 T. Last previous edition D 2810 – 72 (1996). Standardsrecommendationsaresoldbyreputablelaboratorysupplyhousesandmay
2
A Waring Blender has been found satisfactory. be used.
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D2810
a 0.1 N carbonate-free solution of sodium
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