ASTM D4905-99(2020)

Standard Practice for Preparation of Solution of Solid, Pasty and Powdered Vegetable Tannin Extracts

SIGNIFICANCE AND USE
4.1 The concentration of tannins in solid, pasty, and powdered extracts needs to be reduced to analytical strength for tannin analyses.  
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 Since extracts have greater solubility in hot water than cold, it is desirable to dissolve and disperse an extract in hot water and then let the solution cool slowly to standard room temperature.  
4.5 It is often difficult to reduce samples of solid and particularly pasty extracts to specimen size and at the same time ensure representative sampling. Therefore, caution is advised in drawing conclusions on the precision and bias of the results obtained on such extracts; where difficulties in sample preparation are experienced, little confidence can be placed in the results.
SCOPE
1.1 This practice covers a standard procedure for use in preparing the analytical solution required for the analysis of solid, pasty, or powdered vegetable tannin extracts.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 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: 30-Nov-2020
• ICS: 59.140.10 - Processes and auxiliary materials
• Technical Committee: D31 - Leather
• Drafting Committee: D31.01 - Vegetable Leather

Relations

• Refers: ASTM D6404-99(2009) - Standard Practice for Sampling Vegetable Materials Containing Tannin
• Effective Date: 01-Apr-2009
• Refers: ASTM D6403-99(2009) - Standard Test Method for Determining Moisture in Raw and Spent Materials
• Effective Date: 01-Apr-2009
• Refers: ASTM D4903-99(2009) - Standard Test Method for Total Solids and Water in Vegetable Tanning Material Extracts
• Effective Date: 01-Apr-2009
• Refers: ASTM D4904-99(2009) - Standard Practice for Preparation of Solution of Liquid Vegetable Tannin Extracts
• Effective Date: 01-Apr-2009
• Refers: ASTM D4903-99(2004) - Standard Test Method for Total Solids and Water in Vegetable Tanning Material Extracts
• Effective Date: 01-Apr-2004
• Refers: ASTM D4904-99(2004) - Standard Practice for Preparation of Solution of Liquid Vegetable Tannin Extracts
• Effective Date: 01-Apr-2004
• Refers: ASTM D6403-99(2004) - Standard Test Method for Determining Moisture in Raw and Spent Materials
• Effective Date: 01-Apr-2004
• Refers: ASTM D6404-99(2004) - Standard Practice for Sampling Vegetable Materials Containing Tannin
• Effective Date: 01-Apr-2004
• Refers: ASTM D6403-99 - Standard Test Method for Determining Moisture in Raw and Spent Materials
• Effective Date: 10-May-1999
• Refers: ASTM D4904-99 - Standard Practice for Cooling of Analytical Solutions
• Effective Date: 10-May-1999
• Refers: ASTM D6404-99 - Standard Practice for Sampling Vegetable Materials Containing Tannin
• Effective Date: 10-May-1999
• Refers: ASTM D4903-99 - Standard Test Method for Total Solids and Water in Vegetable Tanning Material Extracts
• Effective Date: 10-May-1999

Overview

ASTM D4905-99(2020) – Standard Practice for Preparation of Solution of Solid, Pasty and Powdered Vegetable Tannin Extracts establishes a uniform procedure for preparing analytical solutions from solid, pasty, or powdered vegetable tannin extracts. Developed by ASTM International, this standard is essential for accurate tannin analysis in products derived from vegetable sources. The practice addresses the challenges of sample preparation and solution consistency, ensuring that samples are suitable for precise tannin content evaluation in laboratory and industrial contexts.

Key Topics

• Analytical Strength Solutions: The standard specifies how to dilute concentrated tannin extracts to an appropriate strength for reliable analysis.
• Sample Preparation: Guidelines describe methods for crushing and homogenizing samples, particularly for solid and pasty forms that are difficult to sample representatively.
• Solubility Considerations: Emphasizes the influence of temperature and water quality on the dissolution and dispersion of extract components, recommending dissolution in hot water followed by controlled cooling.
• Moisture Content and Handling: Outlines steps to equilibrate samples with laboratory atmospheric moisture and correctly adjust calculations for moisture differences.
• Prevention of Contamination and Deterioration: Provides recommendations for the use of formaldehyde or toluene additives when necessary to prevent fermentation and mold during solution preparation.

Applications

• Tannin Analysis in Quality Control: This standard is vital for laboratories assessing the purity and concentration of vegetable tannin products, supporting accurate results in quality control processes.
• Leather Industry Testing: Vegetable tannins are commonly used in leather tanning. Accurate solution preparation ensures the validity of tests for tanning strength and raw material quality.
• Research and Product Development: Researchers formulating new vegetable tannin-based products use this method to establish repeatable and comparable analytical baselines.
• Compliance with Regulatory Requirements: Adhering to ASTM D4905-99(2020) helps organizations demonstrate compliance with global trade and industry standards, especially in contexts governed by the World Trade Organization Technical Barriers to Trade (TBT) principles.

Related Standards

Implementing ASTM D4905-99(2020) may also require referencing several related ASTM standards for complete analytical workflows:

• ASTM D4903 – Test Method for Total Solids and Water in Vegetable Tanning Material Extracts
• ASTM D4904 – Practice for Cooling of Analytical Solutions
• ASTM D6403 – Test Method for Determining Moisture in Raw and Spent Materials
• ASTM D6404 – Practice for Sampling Vegetable Materials Containing Tannin

These standards provide complementary procedures for sampling, moisture determination, and solution handling to ensure robust and repeatable analytical outcomes.

---

Keywords: ASTM D4905-99, vegetable tannin extracts, tannin analysis, tannin solution preparation, analytical methods, standardized testing, sample preparation, solubility, quality control, leather industry.

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.
Designation: D4905 − 99 (Reapproved 2020)
Standard Practice for
Preparation of Solution of Solid, Pasty and Powdered
Vegetable Tannin Extracts
This standard is issued under the fixed designation D4905; 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 2.2 ALCA Method:
A11 Preparation of Solution of Solid, Pasty, and Powdered
1.1 This practice covers a standard procedure for use in
Extracts
preparing the analytical solution required for the analysis of
solid, pasty, or powdered vegetable tannin extracts.
3. Summary of Practice
1.2 The values stated in SI units are to be regarded as
3.1 This practice describes a procedure to follow in the
standard. No other units of measurement are included in this
preparation of analytical strength solutions from samples of
standard.
solid, pasty, and powdered vegetable tannin extracts.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 4. Significance and Use
responsibility of the user of this standard to establish appro-
4.1 The concentration of tannins in solid, pasty, and pow-
priate safety, health, and environmental practices and deter-
dered extracts needs to be reduced to analytical strength for
mine the applicability of regulatory limitations prior to use.
tannin analyses.
1.4 This international standard was developed in accor-
4.2 Vegetable tannin extracts are heterogeneous mixtures of
dance with internationally recognized principles on standard-
components with varying solubility.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
4.3 The solubility of such extracts is influenced by tempera-
mendations issued by the World Trade Organization Technical ture and concentration, which affect the degree of dispersion
Barriers to Trade (TBT) Committee.
and size of the component particles.
4.4 Since extracts have greater solubility in hot water than
2. Referenced Documents
cold, it is desirable to dissolve and disperse an extract in hot
2.1 ASTM Standards:
water and then let the solution cool slowly to standard room
D4903 Test Method for Total Solids and Water in Vegetable
temperature.
Tanning Material Extracts
4.5 It is often difficult to reduce samples of solid and
D4904 Practice for Cooling of Analytical Solutions
particularly pasty extracts to specimen size and at the same
D6403 Test Method for Determining Moisture in Raw and
time ensure representative sampling. Therefore, caution is
Spent Materials
advised in drawing conclusions on the precision and bias of the
D6404 Practice for Sampling Vegetable Materials Contain-
results obtained on such extracts; where difficulties in sample
ing Tannin
preparation are experienced, little confidence can be placed in
the results.
This practice is under the jurisdiction ofASTM Committee D31 on Leather and
is the direct responsibility of Subcommittee D31.01 on Vegetable Leather. This
5. Specimen
practice has been adapted from, and is a replacement for, MethodA11 of the Official
Methods of the American Leather Chemists Association.
5.1 The specimen shall consist of a portion of the extract
Current edition approved Dec. 1, 2020. Published December 2020. Originally
sample, prepared as described in Practice D6404, sufficient to
approved in 1989. Last previous edition approved in 2016 as D4905 – 99 (2016).
DOI: 10.1520/D4905-99R20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Official Methods of the American Leather Chemists Association. Available
Standards volume information, refer to the standard’s Document Summary page on from the American Leather Chemists Association, University of Cincinnati, P.O.
the ASTM website. Box 210014, Cincinnati, OH 45221–0014.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4905 − 99 (2020)
give a solution containing as nearly as possible4gof tannin 7.2.1 Treat the air-dried sample, prepared as above, as in
per L (not less than 3.75 g, nor more than 4.25 g, per L). paragraph 7.1, above. In such
...