ASTM International Standard Test Method for Determining Non-Tannins and Tannin in Extracts of Vegetable Tanning Materials ASTM D6401-99(2016)

1.1 This test method is intended for use in determining the quantity of soluble non-tannins and tannin in solutions of tannin extracts, water extracts of vegetable tanning materials, or tanning liquors. The method is applicable to the analysis of liquid, solid, pasty, and powdered extracts and to extracts of raw or spent materials. 1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only. 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.