Overview
EN ISO 9377-2:2000 - "Water quality - Determination of hydrocarbon oil index - Part 2: Method using solvent extraction and gas chromatography" specifies a laboratory method to quantify the hydrocarbon oil index in water by solvent extraction followed by gas chromatography with flame ionization detection (GC‑FID). The method is applicable to surface water, waste water and effluents from sewage treatment plants and supports quantification of hydrocarbon oil concentrations above 0.1 mg/L. It is not intended for volatile mineral oil quantification and can provide qualitative information on oil composition from chromatogram patterns.
Key topics and technical requirements
- Principle: solvent extraction → clean‑up on Florisil → analysis by capillary GC (non‑polar column) with FID; total peak area integrated between the retention times of n‑decane (C10) and n‑tetracontane (C40) defines the hydrocarbon oil index by GC‑FID.
- Definition: hydrocarbon oil index = sum of compounds extractable with a hydrocarbon solvent, not adsorbed on Florisil, eluting between n‑decane and n‑tetracontane.
- Extraction solvent: hydrocarbon solvent or technical hydrocarbon mixture with boiling range ≈ 36 °C to 69 °C (change of solvent requires repeatability tests).
- Clean‑up: Florisil (150–250 µm; heated 140 °C for 16 h, stored in desiccator) to remove polar interferences.
- Calibration & QC: external calibration using a two‑type mineral oil mixture (type A with discrete peaks, type B with unresolved lubricant pattern); example calibration levels given (0; 0.2; 0.4; 0.6; 0.8; 1.0 mg/mL). QC standards and system‑performance checks (n‑alkane mix) are described.
- Interferences & limits: surfactants, polar substances and some halogenated hydrocarbons may affect extraction or GC results; method not suitable for volatile mineral oils.
- Sampling & preservation: follows ISO 5667‑3 guidance for sample handling and preservation.
Practical applications
- Routine monitoring of mineral‑oil contamination in rivers, lakes, industrial discharges and wastewater treatment effluents.
- Regulatory compliance testing where hydrocarbon oil index reporting is required.
- Source‑tracking and qualitative screening of hydrocarbon contamination using chromatogram patterns (e.g., diesel‑like vs. lubricant‑like profiles).
- Laboratory method validation, interlaboratory comparisons and quality assurance in environmental testing programs.
Who should use this standard
- Environmental and water‑testing laboratories performing GC‑FID analyses.
- Industrial environmental compliance teams monitoring effluent quality.
- Regulatory agencies and consultants involved in water quality assessment, pollution control and enforcement.
- Method developers and QA/QC personnel setting up calibration and clean‑up procedures for hydrocarbon analysis.
Related standards
- EN/ISO 9377‑1 - Method using solvent extraction and gravimetry (other part of ISO 9377 series)
- ISO 5667‑3 - Sampling; guidance on preservation and handling of water samples
- ISO/TR 11046 - Mineral‑oil content of soils/sediments (for soil/sediment applications)
Keywords: EN ISO 9377-2:2000, water quality, hydrocarbon oil index, GC‑FID, solvent extraction, Florisil clean‑up, mineral oil, wastewater monitoring.