Overview
ISO 14181:2000 specifies a validated gas chromatographic method for the determination of residues of organochlorine pesticides in animal feeding stuffs. The standard covers extraction, clean‑up and chromatographic determination (electron capture detector or mass selective detector) for compounds such as aldrin, DDE/DDT isomers, dieldrin, endosulfan, endrin, HCB, the four HCH isomers (including lindane), heptachlor and heptachlor epoxide, TDE (DDD) isomers and methoxychlor. Lower determination limits are stated (generally 0.005 µg/g, 0.01 µg/g for DDT isomers, 0.05 µg/g for methoxychlor).
Key topics and technical requirements
- Sample preparation: Laboratory sample preparation per ISO 6498 (grinding to pass a 1 mm sieve for low‑moisture feeds; chopping for high‑moisture feeds). Typical test portions are 50 g (dry/low moisture) or 100 g (high moisture).
- Extraction and partitioning: Test portion extracted with acetone, diluted with water/saturated NaCl and partitioned into dichloromethane.
- Clean‑up: Concentrated extracts purified on a chromatographic column packed with 10% water‑deactivated silica gel; elution with dichloromethane/hexane mixtures.
- Chromatography: Analysis by GC–ECD or GC–MS (mass selective detector) with splitless or on‑column injection. Capillary columns with mid‑polarity phases (e.g., SE‑30/OV‑17 equivalents) are recommended; new columns should be conditioned before use.
- Standards and controls: Use certified pesticide reference standards; mirex or pentachloronitrobenzene as internal standard. Stock/intermediate/working solutions and storage guidance are provided.
- Performance and quality: The standard includes precision data (interlaboratory tests, repeatability, reproducibility), recovery checks, blank controls and confirmation of identity. Normative references include ISO 3696 (water) and ISO 6498 (sample prep).
Applications and users
ISO 14181:2000 is intended for:
- Feed testing laboratories performing pesticide residue surveillance and compliance testing
- Regulatory authorities enforcing feed safety and maximum residue limits
- Feed manufacturers and quality‑assurance teams monitoring raw materials and finished feeds
- Research and environmental laboratories studying organochlorine contamination in animal feeds
Practical uses include routine monitoring, method validation, enforcement sampling and forensic confirmation of organochlorine residues.
Related standards
- ISO 3696:1987 - Water for analytical laboratory use
- ISO 6498 - Animal feeding stuffs - Preparation of test samples
- ISO 6497 - Recommended sampling of animal feeding stuffs (sampling guidance referenced)
Annexes in ISO 14181 provide example GC operating conditions and interlaboratory test results for further guidance.
Keywords: ISO 14181:2000, organochlorine pesticides, animal feeding stuffs, gas chromatography, pesticide residues, GC‑ECD, GC‑MS, silica gel clean‑up, method validation.