ISO 13906:2008 PDF

Overview

ISO 13906:2008 specifies a gravimetric routine and reference method for determining acid detergent fibre (ADF) and acid detergent lignin (ADL) in all types of animal feeding stuffs. The standard defines the chemical principle, required reagents and apparatus, sample preparation and testing procedure. Limits of determination are 1 % mass fraction for ADF and 1.5 % mass fraction for ADL. The method is widely used in feed analysis laboratories for reliable measurement of fibrous components that affect digestibility and feed quality.

Key Topics

• Analytical principle: ADF is the insoluble residue after treatment with a cationic detergent in 0.5 mol/l sulfuric acid (primarily cellulose, lignin and insoluble protein complexes). ADL is the residue remaining after treatment with 72 % (12.00 mol/l) sulfuric acid, which solubilizes cellulose and leaves lignin.
• Reagents: Acid detergent solution (cetyl(trimethyl)ammonium bromide in 0.5 mol/l H2SO4), 72 % H2SO4, acetone, diatomaceous earth (filtration aid), n‑octanol (antifoam).
• Apparatus: Analytical balances, mills (target particle size 0.22–0.26 mm), air‑ventilated and vacuum ovens, refluxing or Fibertec‑type extraction units, fritted‑disk crucibles, vacuum filtration manifold, incineration furnace.
• Sample preparation: Follow ISO 6498 for test sample preparation; dry samples to