ASTM D6407-99

Standard Test Method for Analysis of Iron and Copper in Vegetable Tanning Materials

SCOPE
1.1 This test method is intended for use in determining iron and copper content in vegetable tanning materials. This test method is applicable to liquid, solid, pasty and powdered extracts, to raw and spent materials, and to tannery liquors.
1.2 The values stated in SI units are to be regarded as the 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: 09-May-1999
• ICS: 59.140.10 - Processes and auxiliary materials
• Technical Committee: D31 - Leather
• Drafting Committee: D31.01 - Vegetable Leather

Relations

• Replaced By: ASTM D6407-99(2004) - Standard Test Method for Analysis of Iron and Copper in Vegetable Tanning Materials
• Effective Date: 01-Apr-2004
• Referred By: ASTM D4899-99(2020) - Standard Practice for Analysis of Vegetable Tanning Materials—General
• Effective Date: 10-May-1999

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D 6407 – 99
Standard Test Method for
Analysis of Iron and Copper in Vegetable Tanning Materials
This standard is issued under the fixed designation D 6407; 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. Significance and Use
1.1 This test method is intended for use in determining iron 4.1 This test method is used to determine the quantity of
and copper content in vegetable tanning materials. This test iron and copper present in vegetable tanning materials or
method is applicable to liquid, solid, pasty and powdered vegetable tannin extracts prepared using Practices D 4901, D
extracts, to raw and spent materials, and to tannery liquors. 6404, or D 6405.
1.2 The values stated in SI units are to be regarded as the 4.2 Because of the possibility of errors in this test method it
standard. is essential that the method be followed exactly in order to
1.3 This standard does not purport to address all of the obtain reproducible results both among specimens within a
safety concerns, if any, associated with its use. It is the laboratory and for analyses between laboratories.
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 Sulfuric Acid, concentrated (96 %).
5.2 Sulfuric Acid Solution, diluted 1:20 with distilled water.
2. Referenced Documents
5.3 Nitric Acid, fuming.
2.1 ASTM Standards: 5.4 Hydrochloric Acid, concentrated (36 %).
D 4901 Practice for Preparation of Solution of Liquid Veg- 5.5 Hydrochloric Acid Solution, 0.1 N.
etable Tannin Extracts 5.6 Bromine Water, saturated solution.
D 4902 Test Method for Evaporation and Drying of Ana- 5.7 Ammonium Hydroxide Solution, concentrated diluted
lytical Solutions 1:1 with distilled water.
D 4905 Practice for Preparation of Solution of Solid, Pasty, 5.8 Potassium Permanganate Solution, 0.1 N.
and Powdered Vegetable Tannin Extracts 5.9 Potassium (or Ammonium) Thiocyanate Solution,10g
D 6404 Practice for Sampling of Vegetable Materials Con- shall be dissolved in distilled water and diluted to 100 mL with
taining Tannin distilled water.
D 6405 Practice for Extraction of Tannins from Raw and 5.10 Stock Iron Solution, This may be a purchased iron
Spent Materials standard solution or may be prepared as follows:
2.2 ALCA Methods: 5.10.1 0.70 g of crystallized ferrous ammonium sulfate
A31 Method for Copper and Iron in Tanning Materials [FeSO •(NH ) SO •6H O] shall be dissolved in 50 mL of
4 4 2 4 2
distilled water and 20 mL of dilute sulfuric acid (diluted 1:4).
3. Summary of Test Method
5.10.2 This solution shall be titrated with 0.1 N potassium
3.1 A specified quantity of the tanning material is analyzed permanganate solution until a faint pink persists for 1 minute
for iron and copper and content.
and the iron is completely oxidized.
5.10.3 Dilute this solution to 1 L with distilled water. 1 mL
of this solution is equivalent to 0.0001 g Fe. This solution shall
This test method is under the jurisdiction of ASTM Committee D-31 on Leather
be stored in brown bottles and be protected from light.
and is the direct responsibility of Subcommittee D31.01 on Vegetable Leather. This
5.10.4 Standard Iron Solution, 10 mL of the prepared stock
test method has been adapted from and is a replacement for Method A31 of the
Official Methods of the American Leather Chemists Association. solution, or its equivalent of purchased iron standard solution,
Current edition approved May 10, 1999. Published August 1999.
shall be diluted to 100 mL with distilled water. 1 mL of this
Annual Book of ASTM Standards, Vol 15.04.
standard solution is equivalent to 0.00001 g Fe. The standard
Official Methods of the American Leather Chemists Association. Available
solution shall be freshly prepared for each analysis.
from the American Leather Chemists Association, University of Cincinnati, P.O.
Box 210014, Cincinnati, OH 45221-0014.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 6407
5.11 Stock Copper Solution, 3.9283 g of copper sulfate forms may be used, provided: they be used in matched sets and
crystals (CuSO •5H O) shall be dissolved in distilled water the volumes of reagents, specimen and standard solutions be
4 2
and diluted to 1 L with distilled water. 1 mL of this solution is adjusted so that similar color intensities are produced. Such
equivalent to 0.001 g Cu. adjustments are automatic with, and familiar to, the experi-
5.11.1 Standard Copper Solution, 10 mL of the stock copper enced analyst and are not precluded by the method. If,
solution shall be diluted to 1 L with distilled water and the pH however, the analyst is in doubt as to the proper adjustment to
adjusted to between 5.5 and 6.0. 1 mL of this standard solution be made, it is recommended that 50 mL tall-form tubes be used
is equivalent to 0.00001 g Cu. The standard solution shall be exactly as described.
freshly prepared for each analysis. 7.6 Comparison of the colors developed in the Nessler tubes
5.12 Xanthate Solution, 1.0 g of potassium ethyl xanthate shall be made under a source of daylight from the north, the
shall be dissolved in distilled water and diluted to 1 L with tubes being held vertically two inches above an inclined sheet
distilled water. The solution shall be freshly prepared for each of white paper, and viewed downward through the full depth of
analysis. liquid.
5.13 Matched Nessler Tubes and Supporting Rack.
8. Procedure
5.14 Balance, analytical balance which will weigh up to 100
g with an accuracy of 6 0.1 mg (6 0.0001 g).
8.1 Transfer the specimen to a tared, glazed, porcelain dish
5.15 Drying Oven, a forced-air convection oven (or
or crucible of suitable size, taking care to avoid changes in
mechanical-convection draft oven) capable of maintaining a
moisture content, and weigh to the nearest 0.1 mg (0.0001 g).
temperature of 100 6 2.0°C.
Where necessary, place the dish and specimen in the oven and
5.16 Thermometer, accurate to 6 0.2°C used to check and
evaporate to dryness (Test Method D 4902).
monitor the oven set point.
8.2 Ignite the dish containing the dried residue gently over
5.17 Dessicator, any convenient form or size, using any
a low flame, at as low a temperature as possible, until the
normal desiccant. residue is thoroughly charred and all smoke driven off. Then
5.18 Glazed, Porcelain Dish or Crucible of Suitable Size.
place the dish and charred residue in a muffle furnace and ash,
5.19 Muffle Furnace, capable of maintaining a temperature at a temperature not exceeding 600°C, until all carbon has been
of 600° 6 25°C.
removed.
5.20 Hotplate, ordinary lab grade.
NOTE 1—Occasionally, the specimen will be of such a nature that all the
5.21 Steam Bath, ordinary lab grade.
carbon cannot be removed as described above. In such a case, saturate the
5.22 Volumetric Flasks, 200 and 250 mL capacity.
charred mass with hot distilled water and break it up as completely as
5.23 Beakers, 250 mL.
possible with a glass rod. Then add more of the hot distilled water and
digest the whole on the steam bath for a few minutes. Decant the
5.24 Filter Paper, quantitative, Whatman grade 40 or 52 or
supernatant through a quantitative filter paper, collect the filtrate in a
similar.
suitable receiver. Digest the charred residue twice more with hot distilled
5.25 Buret, 10 mL capacity is sufficient.
water, decant the supernatant through the same filter each time, and
combine the filtrates. Finally transfer the char to the filter and wash several
6. Test Specimen
times with hot distilled water, the washings being combined with the
6.1 The sample of material from which the test specimens
filtrates. Then replace the filter and residue in the original dish, dry, and
are taken shall be prepared as described in Practice D 6404 for
ash the whole, as before, until all the carbon has been removed. Cool the
extracts and tannery liquor and as in the Preparation of Sample dish, quantitatively transfer the combined filtrates and washings thereto
and evaporate and dry. Then place the dish and contents in a cold muffle
section of Practice D 6405 for raw and spent materials.
furnace, raise the temperature, slowly at first to avoid loss by spurting, and
6.2 The specimen shall consist of 5 g of solid extract or its
finally bring to a value not exceeding 600°C.
equivalent (that is 10 g of liquid extract; 25 to 50 g of tannery
8.3 Cool the carbon-free ash, moisten with hot distilled
liquor;5gofraw or spent materials).
water, 5 mL of concentrated hydrochloric acid added, and heat
7. General Instructions
the mixture on the steam bath until the ash is dissolved. Add
the five drops of fuming nitric acid and five drops of
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