Determination of Sulphated Ash of water soluble matter – Leather Accessories

A specified amount of leather is shaken with water in a shaker under specified conditions. The dissolved substances are then evaporated. The residue is then treated with sulphuric acid and finally the percentage of the sulphated ash is calculated on the weight of the original material taken


  • Take the dish with residue as obtained in above test for water soluble matter.
  • Wet the residue in the dish with few drops of 2N sulphuric acid.
  • Fume over low flame, till no sulphuric acid vapors are visible.
  • Then shift the dish in muffle furnace maintained at 800° ± 25°C
  • Heat until red hot for 15 to 20 minutes.
  • Cool in a Desiccator and weigh as quick as possible.
  • Repeat the addition of acid, heating, cooling and weighing until the weight of residue is constant.


Calculate the sulphated ash of water soluble matter as follows:

Sulphated ash of water soluble matter, percent by weight = W1 X 100 / W2


W1= weight in g of the sulphated ash, and

W2 = weight in g of the prepared material taken before extracting the solvent soluble substances

Permissible Error – 

The results of a duplicate determination shall not differ from one another by more than 0.2 percent calculated on the original weight of the material taken for the test.

REFERANCE: – IS 582:1970 (LC 7) – methods of chemical testing of leather.

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