Overview
ISO/TS 28581:2012 - "Water quality - Determination of selected non-polar substances - Method using gas chromatography with mass spectrometric detection (GC‑MS)" - specifies a validated analytical procedure for measuring selected non‑polar organic compounds in water by gas chromatography–mass spectrometry (GC‑MS). The method targets polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), organochlorine pesticides and other non‑polar substances in drinking water, groundwater, surface water and wastewater at low trace levels (typical limits: 0.005 μg/L for drinking/groundwater; 0.01 μg/L for surface/wastewater). The procedure covers sample extraction, concentration, clean‑up, separation and mass‑spectrometric identification/quantification.
Key Topics and Requirements
- Scope and analytes: Lists determinable non‑polar substances (PAH, PCB, organochlorine pesticides) and notes applicability to similar non‑polar compounds after verification.
- Sampling limits: Usable for samples with up to 150 mg/L suspended matter; sampling/preservation references to ISO 5667 series.
- Sample preparation: Liquid–liquid extraction (hexane or equivalent solvents) with an internal standard mixture added before extraction; concentration by evaporation and solvent exchange where needed.
- Clean‑up: Optional column chromatography for surface or wastewater extracts to remove interferences.
- Chromatography: Separation on fused‑silica capillary columns with non‑polar or slightly polar polysiloxane stationary phases suitable for isomer separation.
- Mass spectrometry: Electron‑impact (EI) ionization and use of selected ion monitoring (SIM) for identification/quantification; injection standards added prior to GC injection.
- Calibration & QC: Calibration using internal or isotopically labelled internal standards; blank measurements, recovery checks, and performance criteria are specified (see ISO 8466‑1 for calibration evaluation).
- Interferences: Guidance on sampling, extraction, GC and MS interferences and required verification for novel analytes.
Applications - Who Uses This Standard
- Environmental and water‑testing laboratories performing routine monitoring of drinking water, groundwater, surface water and wastewater.
- Regulatory agencies and drinking water utilities enforcing contaminant limits (e.g., benzo[a]pyrene and other PAH).
- Contract laboratories providing compliance testing for pesticides, PCBs and PAH.
- Research groups developing or validating trace‑level methods for non‑polar organic contaminants.
Related Standards
- ISO 28540 - Determination of PAH by GC‑MS
- ISO 5667‑1 / ISO 5667‑3 - Sampling guidance and preservation
- ISO 6468 - GC method after liquid–liquid extraction for specific insecticides/PCBs
- ISO 8466‑1 - Calibration and evaluation of analytical methods
- ISO/TS 13530 - Verification methods for analytical applicability
Keywords: ISO/TS 28581:2012, water quality, GC‑MS, gas chromatography mass spectrometry, non‑polar substances, PAH, pesticide residues, drinking water testing, liquid‑liquid extraction.