Analysis of gallotannin in the tanning substances of sumac part 2: Titrimetric method for the determination of gallotannin in residual solutions from sumac extract tanning

作者：Kolusheva T; Costadinnova L; Ivanova D^*

来源：Journal of the Society of Leather Technologists and Chemists, 2008, 92(1): 19-22.

We have developed a method for the determination of gallotannin in residual solutions from tanning with sumac extract. The method consists of hydrolysis of gallotannin to gallic acid in hydrochloric medium at boiling temperature for 15 minutes; titration at high temperature with standard solution of NaOH of the strong hydrochloric and the weak gallic acid in two samples containing equal amounts of HCl and tannin against different indicators.
We investigated the interfering influence of synthetic tanning agents, HCOOH, metallic ions, tanning substances and salts. We have proved the absence of systematic errors in the proposed procedure for residual solutions from plant-synthetic tanning.
The reproducibility of the results for gallotannin concentration 18.2g/l is good, S-r = 0.8%. This method can also be applied for tanning with extracts from Rhus semialata (Chinese galls) and Caesalpinia spinosa (Tara).

• 出版日期2008-2
• 单位北京化工大学