EN ISO 13906:2008 PDF

Overview

EN ISO 13906:2008 (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 method is a two‑stage chemical/gravimetric procedure: ADF is measured after treatment with a cationic detergent in 0.5 mol/L sulfuric acid, and ADL is determined by solubilizing remaining cellulose with 72 % (m/m) sulfuric acid to leave lignin. The standard sets the limits of determination at 1 % mass fraction for ADF and 1.5 % mass fraction for ADL.

Key topics and technical requirements

• Principle: two‑stage treatment - removal of acid‑labile carbohydrates and non‑complexed protein (ADF), then cellulose solubilization to isolate lignin (ADL).
• Limits of determination: ADF ≥ 1 %, ADL ≥ 1.5 % (mass fraction).
• Reagents:
  • Acid detergent solution: 20 g cetyl(trimethyl)ammonium bromide per 1 L of 0.5 mol/L H2SO4.
  • 72 % (m/m) sulfuric acid (≈12.00 mol/L) for lignin determination (standardization and density guidance provided).
  • Filtration aid (diatomaceous earth), acetone, n‑octanol (antifoam).
• Apparatus:
  • Analytical balances (0.1 mg readability), mills producing 0.22–0.26 mm mean particle size, air‑ventilated ovens (103 °C or 130 °C for ash/moisture; **