Overview
ISO 17180:2013 specifies a validated analytical method for the quantitative determination of free (non‑protein‑bound) lysine, methionine and threonine in commercial amino‑acid products and premixtures used in animal feeding stuffs. The standard is applicable when the product contains about 10% or more mass fraction of the respective amino acid and does not distinguish between D‑ and L‑forms. The method uses an amino‑acid analyser or HPLC with a cation‑exchange column and post‑column derivatization for detection.
Key topics and technical requirements
- Scope: Quantification of free lysine, methionine and threonine in commercial products and premixtures (> ~10%).
- Principle: Acid extraction (dilute HCl), neutralization/dilution with sodium citrate buffer, addition of norleucine internal standard, chromatographic separation on a cation‑exchange column, and detection after post‑column reaction (ninhydrin colorimetry or OPA fluorescence).
- Sample preparation: Grind to pass 0.25 mm, prepare two extracts per sample, and choose between dilution by weighing or volumetric dilution depending on sample type (pure amino acids vs. premixes).
- Reagents & standards: Use high‑purity amino acid standards (≥99%) and norleucine internal standard (c = 2.5 mmol/L). Prepare calibration solutions by weight or volume dilution with sodium citrate buffer.
- Chromatography & detection: Cation exchange resin, guard column, automated injection (10–100 µL typical), post‑column derivatization with ninhydrin (UV detection at 440/570 nm) or OPA (fluorescence 330/460 nm). Baseline separation of analyte peaks is required to avoid overlap.
- Quality control & calibration: Inject calibration solution as QC after every four test samples; acceptable recovery range is 99–101%. The standard includes procedures for calculating results and addresses precision (repeatability and reproducibility).
- Sample/storage notes: Filter extracts through 0.2 µm membrane; store below 5 °C (calibration solutions ≤1 week; sample extracts up to specified days).
Applications and who uses it
ISO 17180:2013 is used by:
- Feed manufacturers and formulators for quality control of commercial amino‑acid products and premixtures.
- Analytical and contract testing laboratories performing amino acid quantification for specification compliance.
- Regulatory bodies and inspection laboratories validating label claims or investigating feed composition.
- R&D teams optimizing feed formulations and ingredient quality.
Practical benefits include reproducible quantification of key essential amino acids (lysine, methionine, threonine), traceable calibration using an internal standard, and compatibility with common lab instrumentation (amino‑acid analyzers or HPLC).
Related standards (if applicable)
For broader feed analysis and laboratory practice, laboratories often consult other ISO standards covering animal feeding stuffs, sample preparation, and chromatographic methods for comprehensive quality management and method validation.