Overview
ISO 28540:2011 - "Water quality - Determination of 16 polycyclic aromatic hydrocarbons (PAH) in water - Method using gas chromatography with mass spectrometric detection (GC‑MS)" - specifies a validated laboratory procedure for measuring at least 16 priority PAH in drinking water, groundwater and surface water using GC‑MS. The method covers individual compound mass concentrations above 0.005 µg/L (drinking and ground water) and 0.01 µg/L (surface water), and is suitable for samples with up to 150 mg/L suspended matter. With appropriate validation or modification it can be adapted for wastewater and additional PAH.
Key technical topics and requirements
- Analytes: 16 PAH listed in Table 1 (includes benzo[a]pyrene, indeno[1,2,3‑cd]pyrene, benzo[b]fluoranthene, etc.).
- Sample preparation: Liquid–liquid extraction (hexane) with internal standards added prior to extraction; extracts concentrated and re‑solvated for cleanup or GC injection.
- Standards & internal controls: Use of isotopically labelled internal standards (minimum three) and an injection standard to monitor recovery and instrument response.
- Chromatography & detection: GC separation on fused silica capillary columns (non‑polar or slightly polar polysiloxane) capable of resolving critical pairs (e.g., benzo[a]pyrene / benzo[e]pyrene); identification/quantification by mass spectrometry with electron impact ionization (EI) and selective ion monitoring (SIM/SIR) where appropriate.
- Quality criteria & interferences: Guidance on resolution (e.g., R ≥ 0.8 for certain critical peak pairs), handling co‑eluting interferents, storage and sampling precautions (avoid plastics, use amber containers), and limits on suspended solids. Recommended reagent and gas purities (hexane, acetonitrile, nitrogen, helium) and precleaning (anhydrous sodium sulfate).
- Documentation & annexes: Includes examples of GC‑MS conditions, precision/accuracy data, apparatus construction and chromatograms to support method implementation.
Practical applications and who uses this standard
- Environmental testing laboratories performing water quality monitoring for PAH contamination.
- Public health and regulatory agencies verifying compliance with drinking water standards (e.g., EU Directive references such as benzo[a]pyrene limits).
- Industrial and wastewater testing facilities adapting methods for effluent monitoring after validation.
- Academic and research labs studying PAH occurrence, fate and transport in aquatic systems.
Practical benefits: reproducible GC‑MS workflow, trace‑level detection guidance, standardized reporting and QA/QC to support regulatory compliance and environmental risk assessments.
Related standards
Keywords: ISO 28540:2011, PAH, polycyclic aromatic hydrocarbons, water quality, GC‑MS method, benzo[a]pyrene, drinking water testing, environmental monitoring, liquid‑liquid extraction.