ASTM D4901-99(2016)

Standard Practice for Preparation of Solution of Liquid Vegetable Tannin Extracts

SIGNIFICANCE AND USE
4.1 The concentration of tannin in extracts must be reduced to analytical strength (4 g tannin per L) for analysis.  
4.2 Vegetable tannin extracts are heterogeneous mixtures of components with varying solubility.  
4.3 The solubility of such extracts is influenced by temperature and concentration, which affect the degree of dispersion and size of the component particles.  
4.4 While the solubility is better in hot water than in cold water, it is appropriate to dissolve and disperse an extract in hot water and then let the solution cool slowly to standard room temperature.
SCOPE
1.1 This practice covers the preparation of a solution of liquid extract that is to be used in the tannin analysis of that extract.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 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: 31-Aug-2016
• ICS: 59.140.10 - Processes and auxiliary materials
• Technical Committee: D31 - Leather
• Drafting Committee: D31.01 - Vegetable Leather

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D4901 − 99 (Reapproved 2016)
Standard Practice for
Preparation of Solution of Liquid Vegetable Tannin Extracts
This standard is issued under the fixed designation D4901; 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 4.2 Vegetable tannin extracts are heterogeneous mixtures of
components with varying solubility.
1.1 This practice covers the preparation of a solution of
liquid extract that is to be used in the tannin analysis of that 4.3 The solubility of such extracts is influenced by tempera-
extract. ture and concentration, which affect the degree of dispersion
and size of the component particles.
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this 4.4 While the solubility is better in hot water than in cold
standard. water,itisappropriatetodissolveanddisperseanextractinhot
water and then let the solution cool slowly to standard room
1.3 This standard does not purport to address all of the
temperature.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Apparatus and Reagents
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. 5.1 Formaldehyde—40 % solution.
5.2 Toluene—assay ≥ 99.5 %.
2. Referenced Documents
5.3 Flask,1Lvolumetric.TheClassAtype,withupperbulb
2.1 ASTM Standards:
in neck, is especially suitable for this work.
D4904 Practice for Cooling of Analytical Solutions
D6404 Practice for Sampling Vegetable Materials Contain-
6. Test Specimen
ing Tannin
6.1 The specimen shall consist of an aliquot of the sample,
2.2 ALCA Methods:
prepared as described in Practice D6404, sufficient to give a
A10 Preparation of Solution of Liquid Extracts
solution containing as nearly as possible,4gof tannin per L
(not less than 3.75 g, nor more than 4.25 g, per L).
3. Summary of Practice
3.1 This practice describes a technique found useful in the 7. Procedure
preparation of analytical strength solutions from samples of
7.1 Prepare samples of liquid extracts as described in
liquid vegetable tannin extracts.
Practice D6404, and allow to come to room temperature.
Thoroughly mix at room temperature and transfer specimen to
4. Significance and Use
a tared container and stoppered to prevent loss of moisture.
4.1 The concentration of tannin in extracts must be reduced
Return no material which has been removed from the sample
to analytical strength (4 g tannin per L) for analysis.
for any other purpose (for example, for determination of
specific gravity, etc.) to the sample. Care must be taken that
dried material around the neck of the stopper of the sample
This practice is under the jurisdiction ofASTM Committee D31 on Leather and bottle does not contaminate the sample or specimen.Weigh the
is the direct responsibility of Subcommittee D31.01 on Vegetable Leather. This
container and specimen to the nearest 0.1 mg.
practicehasbeenadaptedfrom,andisareplacementfor,MethodA10oftheOfficial
Methods of the American Leather Chemists Association.
NOTE 1—Shaking by hand is rarely sufficient; mechanical shaking,
Current edition approved Se
...

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: D4901 − 99 (Reapproved 2009) D4901 − 99 (Reapproved 2016)
Standard Practice for
Preparation of Solution of Liquid Vegetable Tannin Extracts
This standard is issued under the fixed designation D4901; 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
1.1 This practice covers the preparation of a solution of liquid extract that is to be used in the tannin analysis of that extract.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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.
2. Referenced Documents
2.1 ASTM Standards:
D4904 Practice for Cooling of Analytical Solutions
D6404 Practice for Sampling Vegetable Materials Containing Tannin
2.2 ALCA Methods:
A10 Preparation of Solution of Liquid Extracts
3. Summary of Practice
3.1 TheThis practice describes a technique found useful in the preparation of analytical strength solutions from samples of liquid
vegetable tannin extracts.
4. Significance and Use
4.1 The concentration of tannin in extracts must be reduced to analytical strength (4 g tannin per L) for analyses.analysis.
4.2 Vegetable tannin extracts are heterogeneous mixtures of components with varying solubility.
4.3 The solubility of such extracts is influenced by temperature and concentration, which affect the degree of dispersion and size
of the component particles.
4.4 While the solubility is better in hot water than in cold water, it is appropriate to dissolve and disperse an extract in hot water
and then let the solution cool slowly to standard room temperature.
5. Apparatus and Reagents
5.1 Formaldehyde—40 % solution.
5.2 Toluene—assay ≥ 99.5 %.
5.3 Flask, 1 L volumetric. The Class A type, with upper bulb in neck, is especially suitable for this work.
6. Test Specimen
6.1 The specimen shall consist of an aliquot of the sample, prepared as described in Practice D6404, sufficient to give a solution
containing as nearly as possible, 4 g of tannin per L (not less than 3.75 g, nor more than 4.25 g, per L).
This practice is under the jurisdiction of ASTM Committee D31 on Leather and is the direct responsibility of Subcommittee D31.01 on Vegetable Leather. This practice
has been adapted from, and is a replacement for, Method A10 of the Official Methods of the American Leather Chemists Association.
Current edition approved April 1, 2009Sept. 1, 2016. Published July 2009October 2016. Originally approved in 1989. Last previous edition approved in 20042009 as
D4901 – 99 (2004).(2009). DOI: 10.1520/D4901-99R09.10.1520/D4901-99R16.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Official Methods of the American Leather Chemists Association. Available fro
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