Overview
ISO 6495-1:2015 specifies a titrimetric method for determining the content of water‑soluble chlorides, expressed as sodium chloride (NaCl), in animal feeding stuffs. The method applies to feed samples with water‑soluble chloride content ≥ 0.05% (as NaCl). First published in 2015, this standard replaces the earlier ISO 6495:1999 and provides a validated laboratory procedure for chloride quantification in feed matrices.
Key topics and technical requirements
- Principle: Dissolve chlorides in water, clarify solutions when organic matter is present, acidify with nitric acid and precipitate chloride as silver chloride using standard silver nitrate, then back‑titrate the excess silver nitrate with ammonium or potassium thiocyanate by Volhard’s method.
- Applicability: For animal feeding stuffs containing ≥0.05% water‑soluble chloride (as NaCl).
- Sample preparation:
- Procedures for samples free from organic matter, and alternate prep for samples containing organic matter.
- Special handling for cooked feeds, flax cakes/flour, mucilage‑rich or colloidal products (use of acetone decantation).
- Use of Carrez I/II reagents, activated carbon, and clarification/filtration steps.
- Reagents & apparatus: Requires analytical‑grade reagents (e.g., AgNO3, thiocyanate titrant, potassium chromate, nitric acid), volumetric glassware, burettes, rotary shaker, analytical balance and appropriate filters.
- Calibration & standards: Preparation and standardization of sodium chloride, silver nitrate and thiocyanate standard solutions (molarities known to 1×10‑4 mol/L). Duplicate titrations must meet agreement criteria.
- Quality aspects: Includes instructions for blank tests, expression of results, precision data (repeatability, reproducibility, interlaboratory testing) and required test reporting.
Applications and users
ISO 6495-1:2015 is used by:
- Feed testing laboratories performing routine chloride analysis for quality control.
- Feed manufacturers and ingredient suppliers checking salt content for formulation and regulatory compliance.
- Regulatory authorities and inspection labs verifying declared feed composition.
- Research labs studying mineral balance or salt intake in animal nutrition.
Practical benefits include standardized, reproducible chloride results using a well‑established titrimetric (Volhard) method, enabling consistent quality control and regulatory reporting.
Related standards
- ISO 6497 - Animal feeding stuffs - Sampling (recommended sampling methods).
- ISO 6498 - Animal feeding stuffs - Guidelines for sample preparation.
- ISO 3696 - Water for analytical laboratory use (water grade requirements referenced).
Keywords: ISO 6495-1:2015, animal feeding stuffs, water-soluble chloride, titrimetric method, silver nitrate titration, Volhard method, NaCl determination, Carrez reagents, feed analysis.