Overview
ISO 15680:2003 specifies a general laboratory method for the determination of volatile organic compounds (VOCs) in water using purge-and-trap isolation followed by gas chromatography (GC) with thermal desorption. The scope covers a range of non‑polar, intermediate‑volatility compounds - from difluorodichloromethane (R‑12) up to trichlorobenzene - including monocyclic aromatic hydrocarbons, naphthalene and several chlorinated compounds. Detection is preferably by GC–mass spectrometry (GC‑MS) in electron‑impact (EI) mode, though other detectors are permitted. The standard applies to drinking water, groundwater, surface water, seawater and diluted wastewater.
Key topics and technical requirements
- Sample preparation and preservation: guidance on sampling, preservation (e.g., sodium thiosulfate for oxidant removal) and avoidance of volatilization or contamination during transport and storage.
- Purge-and-trap principle: stripping VOCs from a fixed sample volume with an inert purge gas (helium or nitrogen recommended), trapping on either a packed adsorbent (with optional cryofocusing) or a capillary cold‑trap, then thermal desorption to the GC.
- Instrumentation: options for packed adsorbent traps or capillary cold traps, on‑line or off‑line transfer, temperature‑programmed GC separation and recommended use of cryofocusing or high split ratios to narrow injection bandwidths.
- Detection and identification: preference for GC‑MS (EI) with criteria for identification given in Annex D; acquisition can be full‑scan or selected fragments.
- Performance characteristics: typical limits of detection depend on detector and settings; ISO 15680 notes LODs as low as 10 ng/L (calculated as 3× standard deviation from replicate samples) and a working range up to ~100 μg/L.
- Quality control: blank determinations, calibration procedures, use of external and retention‑time standards, recovery checks (Annex G), cleaning procedures (Annex E) and preparation of standards (Annex F).
- Interferences: recommendations to avoid plastics, control laboratory air contamination, ensure purge and carrier gas purity, and manage surfactant/foaming risks.
Applications
ISO 15680 is used for:
- Regulatory compliance testing of drinking and environmental waters for VOC contamination
- Environmental monitoring programs (groundwater, surface water, marine)
- Industrial wastewater surveillance and leak/spill investigations
- Contract testing laboratories, environmental consultancies and research into VOC fate and transport
Who should use this standard
- Water‑quality analytical laboratories and technicians
- Environmental regulators and monitoring agencies
- Industrial hygiene and environmental consultants
- Instrument manufacturers and method developers implementing purge‑and‑trap GC methods
Related standards
- ISO 3696 - Water for analytical laboratory use
- ISO 5667‑3 - Sampling: preservation and handling of water samples
- ISO 8466‑1 - Calibration and evaluation of analytical methods
Keywords: ISO 15680, VOCs in water, purge-and-trap, thermal desorption, GC‑MS, water quality analysis, volatile organic compounds, detection limits.