Overview
ISO 6869:2000 specifies a standardized laboratory method for the determination of eight mineral elements in animal feeding stuffs using atomic absorption spectrometry (AAS). The standard covers the measurement of calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), potassium (K), sodium (Na) and zinc (Zn) in feed materials. It defines sample preparation (dry ashing or acid decomposition), calibration and measurement procedures, required reagents and apparatus, and detection limits for routine elemental analysis of animal feed.
Keywords: ISO 6869, animal feeding stuffs, atomic absorption spectrometry, AAS, feed testing, elemental analysis, mineral content.
Key topics
- Scope and detection limits: Applicable to all animal feeding stuffs. Limit of determination: K and Na 500 mg/kg; Ca and Mg 50 mg/kg; Cu, Fe, Mn and Zn 5 mg/kg.
- Principle: Test portions are dissolved in hydrochloric acid (with dry ashing if organic matter is present), silica is removed, and the final solution is aspirated into an air–acetylene flame. Absorbances are compared with calibration solutions.
- Sample preparation: Guidance for detecting organic matter, selecting test portion mass (1–5 g), dry ashing at 550 ± 15 °C, acid decomposition, filtration and blank preparation.
- Reagents and modifiers: Uses analytical-grade reagents, lanthanum nitrate and caesium chloride as matrix modifiers for Ca/Mg/K/Na measurements, and specified stock and working standard solutions for trace metals.
- Instrumentation and settings: AAS with air–acetylene flame and background correction is required. Recommended analytical wavelengths are provided (e.g., Cu 324.8 nm, Fe 248.3 nm, Ca 422.6 nm, K 766.5 nm, etc.).
- Calibration and quality control: Preparation of calibration curves, blank corrections, dilution into linear ranges, and expression of results. The standard also reports precision data from interlaboratory tests.
Applications
ISO 6869 is intended for:
- Feed testing and quality control laboratories verifying mineral composition of feeds and premixes.
- Feed manufacturers and nutritionists ensuring formulation accuracy and nutritional compliance.
- Regulatory and inspection bodies performing compliance testing for mineral content in animal feeding stuffs.
- Research labs conducting elemental analysis in animal nutrition studies.
Practical benefits include standardized, reproducible elemental analysis using AAS, reliable calibration procedures, and specified detection limits to support quality assurance and regulatory reporting.
Related standards
- ISO 3696: Water for analytical laboratory use (reagent water quality)
- ISO 6498: Preparation of test samples for animal feeding stuffs
- ISO 6497: Sampling recommendations (referenced)
- ISO 6956: Guidance on atomic absorption spectrometers (instrument considerations)
Use ISO 6869 for consistent, validated AAS methods when testing mineral contents in feed to support product safety, nutrient labeling and regulatory compliance.