Overview
EN ISO 16035:2005 (ISO 16035:2003) specifies a validated analytical method for the determination of low‑boiling halogenated hydrocarbons in edible oils (animal and vegetable fats and oils). The method uses static headspace gas chromatography (HS‑GC) with an electron capture detector (ECD) and an internal standard to quantify target halogenated solvents in the range 0.01 mg/kg to 0.2 mg/kg. It is intended for use by laboratories performing quality control, compliance testing and safety assessment of edible fats and oils.
Key Topics
- Analytical principle: manual or automatic static headspace sampling of a heated oil sample followed by capillary column GC separation and ECD detection; quantitative evaluation via an internal standard and calibration curves.
- Target compounds: low‑boiling halogenated hydrocarbons commonly encountered as solvent residues (examples listed in the standard include dichloromethane, trichloromethane, 1,1,1‑trichloroethane, tetrachloromethane, 1,1,2‑trichloroethene, tetrachloroethene, bromodichloromethane, dibromochloromethane, tribromomethane and related compounds).
- Internal standard: 2‑bromo‑1‑chloropropane is specified for quantitative analysis.
- Reagents and solvents: use of analytical‑grade isooctane for dilution and calibration; preparation of stock and working standard solutions as described.
- Apparatus and conditions:
- HS‑GC system with ECD and capillary column (example given: fused silica 50 m × 0.32 mm, SE‑54, 1 µm film).
- Injection vials (10–25 ml) with gas‑tight PTFE‑faced septa, gas‑tight syringes for headspace sampling, thermostatted heating bath or block (typical conditioning 80 °C, up to 110 °C for greater sensitivity).
- Carrier gases: nitrogen, helium or hydrogen; appropriate purge gas for ECD.
- Calibration and calculations: calibration solutions prepared by spiking a blank oil; regression analysis from calibration points; expression of results in mg/kg.
- Quality and performance: includes provisions for blank samples, precision assessment (interlaboratory test results, repeatability and reproducibility) and reporting requirements.
- Safety: emphasizes handling rules for hazardous halogenated solvents.
Applications
- Routine testing of edible vegetable and animal oils for solvent residues and halogenated hydrocarbons.
- Food safety and regulatory compliance testing in food laboratories and inspection agencies.
- Quality control in edible oil refining and processing (oil mills, refineries, contract testing labs).
- Investigative testing after solvent‑related incidents or supplier verification.
Related Standards
- ISO 661:1989 - Preparation of test sample for animal and vegetable fats and oils (referenced normative document).
- Adopted by CEN as EN ISO 16035:2005 (CEN/TC 307); prepared by ISO/TC 34/SC 11.
Keywords: EN ISO 16035:2005, low‑boiling halogenated hydrocarbons, edible oils, static headspace gas chromatography, electron capture detector, solvent residues, oil testing, internal standard.