The concentration of tannin in extracts must be reduced to analytical strength (4 g tannin per L) for analyses.

Vegetable tannin extracts are heterogeneous mixtures of components with varying solubility.

The solubility of such extracts is influenced by temperature and concentration, which affect the degree of dispersion and size of the component particles.

While the solubility is better in hot water than in cold water, it is appropriate to dissolve and disperse an extract in hot water and then let the solution cool slowly to standard room temperature.

1. Scope

1.1 This practice covers the preparation of a solution of liquid extract that is to be used in the tannin analysis of that extract.

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 and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D4904 Practice for Cooling of Analytical Solutions

D6404 Practice for Sampling Vegetable Materials Containing Tannin

ALCA Methods

Keywords

analytical solution; tannin analysis; vegetable tannin analysis; Analytical solution; Liquids--leather applications; Preparation; Solid phase materials--leather; Specimen preparation (general); Tanning analysis/materials; Vegetable-tanned leather;

ICS Code

ICS Number Code 59.140.10 (Processes and auxiliary materials)

Citing ASTM Standards

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