Overview
ISO 7106:1985 specifies two laboratory methods for the determination of oil content (non‑volatile at ~105 °C) in liquefied anhydrous ammonia for industrial use. The standard covers sample handling and analysis where a test portion of liquefied ammonia is evaporated at ambient temperature, the residue extracted with carbon tetrachloride, and the oil quantified either by a gravimetric procedure or by infra‑red spectrometric measurement (absorbance at ≈ 3.42 µm).
Key topics and requirements
- Two validated methods
- Gravimetric method: evaporate the organic solvent and weigh the non‑volatile residue. Applicable for oil contents ≥ 10 mg/kg.
- Infra‑red spectrometric method: measure absorbance of the carbon‑tetrachloride organic phase at ~3.42 µm (CH asymmetric vibration). More sensitive; applicable for oil contents > 1 mg/kg.
- Sample collection & apparatus
- Use sampling procedure in ISO 7103; test tube with three‑way stopcocks, Dewar vessel, platinum dish, silica IR cells (1 cm), and fume‑cupboard operations.
- Reagents and standards
- Analytical grade reagents, distilled water.
- Carbon tetrachloride (no absorbance at ~3.42 µm) as extraction solvent; toxic - avoid inhalation and skin contact.
- Paraffin oil standard (e.g., n‑hexadecane) in carbon tetrachloride used for calibration.
- Calibration & expression of results
- IR method requires a calibration graph prepared for each determination (series of reference solutions).
- Results expressed as mg oil per kg ammonia using specified formulae and two replicate determinations.
- Safety
- Liquefied anhydrous ammonia is highly corrosive, toxic (bp −33.3 °C), irritant, and potentially explosive in air mixtures. Work only in well‑ventilated fume hoods with full PPE and appropriate gas‑mask protection.
- Carbon tetrachloride is toxic; handle to avoid vapour exposure.
Applications and users
ISO 7106 is intended for:
- Quality control laboratories in ammonia production and distribution
- Chemical manufacturers and industrial gas suppliers monitoring oil contamination
- Plant safety and compliance teams verifying product purity for downstream chemical processes (fertilizers, refrigeration, synthesis)
- Regulatory bodies and inspection laboratories performing trace oil testing
Using the gravimetric or IR method helps ensure product quality, prevent catalyst poisoning, reduce fouling in process equipment, and demonstrate compliance with contractual or regulatory purity requirements.
Related standards
- ISO 7103 - Liquefied anhydrous ammonia for industrial use - Sampling - Taking a laboratory sample
- ISO 3165 - Safety in sampling of chemical products for industrial use
Keywords: ISO 7106:1985, liquefied anhydrous ammonia, oil content determination, gravimetric method, infra‑red spectrometric method, carbon tetrachloride, ammonia QC, industrial ammonia testing.
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