Overview
ISO 16035:2003 specifies a validated analytical method for the determination of low‑boiling halogenated hydrocarbons in edible fats and oils using static headspace gas chromatography (HS‑GC) with an electron capture detector (ECD). The procedure is designed to detect and quantify common halogenated solvent residues in edible oils in the range 0.01 mg/kg to 0.2 mg/kg, supporting food safety and quality control.
Key topics and technical requirements
- Method principle: Manual or automatic static headspace sampling of the vapour phase above a heated oil sample, separation on a low‑polarity capillary column and detection by ECD with an internal standard for quantification.
- Detection range: 0.01–0.2 mg/kg for the specified low‑boiling halogenated hydrocarbons.
- Target analytes / standards: Examples include dichloromethane, trichloromethane (chloroform), 1,1,1‑trichloroethane, tetrachloromethane, tetrachloroethene and brominated analogues. 2‑bromo‑1‑chloropropane is used as the internal standard.
- Reagents & calibration: Stock and calibration solutions are prepared in isooctane; four calibration levels (I–IV) are used to generate regression curves for quantitation.
- Apparatus: GC with capillary column (e.g., 50 m × 0.32 mm SE‑54, 1 µm), ECD, automatic headspace sampler or manual gas‑tight syringe, thermostatted heating bath/aluminium block for vials.
- Representative operating conditions (examples provided in the standard):
- Heating bath: 80 °C (110 °C optional for increased sensitivity)
- Injector: ~200 °C; Detector: ~280 °C
- Split ratio: 1:30; Carrier gas: nitrogen (~800 hPa)
- ECD purge gas: argon/methane mix or nitrogen (≈30 ml/min)
- Automatic headspace: conditioning time ~60 min; injection time ~5 s
- Quality control: Use of blank vials to monitor laboratory contamination, duplicate analyses, and interlaboratory precision data (repeatability and reproducibility) described in the standard.
Applications
- Routine monitoring of solvent residues in edible oils and fats (vegetable and animal origin).
- Regulatory compliance testing for food safety and import/export control.
- Quality assurance in oil processing and refining to detect contamination from halogenated solvents.
- Research and method validation in analytical laboratories focusing on trace contaminants in food matrices.
Who should use this standard
- Food testing laboratories and contract analytical services
- Regulatory agencies and food safety inspectors
- Oil and fat processors, refiners and quality control teams
- Analytical chemists developing HS‑GC/ECD methods for trace contaminants
Related standards
- ISO 661:1989 - Preparation of test sample for fats and oils (referenced by ISO 16035)
- ISO 5555 - Recommended sampling procedures for edible oils (sampling guidance referenced)
Keywords: ISO 16035:2003, halogenated hydrocarbons, static headspace gas chromatography, HS‑GC, edible oils, electron capture detector, solvent residues, food safety.