Overview
ISO 17495:2001 specifies a validated analytical procedure for the determination of selected nitrophenols in drinking, ground and surface water at mass concentrations of ≥ 0.5 µg/L. The method combines solid‑phase extraction (SPE) for sample enrichment, derivatization with diazomethane, and analysis by gas chromatography with mass spectrometric detection (GC‑MS). The standard defines scope, reagents, apparatus, sampling, procedure, calibration, calculation and reporting requirements to ensure reliable, reproducible results.
Common nitrophenols covered (examples from Table 1):
- 2‑Nitrophenol, 3‑Nitrophenol, 4‑Nitrophenol
- 4‑Methyl‑2‑nitrophenol, 3‑Methyl‑2‑nitrophenol, 3‑Methyl‑4‑nitrophenol
- 2,4‑Dinitrophenol, 2,5‑Dinitrophenol, 2,6‑Dinitrophenol
- 2,4‑Dichloro‑6‑nitrophenol, 2,6‑Dichloro‑4‑nitrophenol, and several methylated/dinitro derivatives
Key Topics & Requirements
- Principle: Acidify sample → SPE enrichment → solvent elution → methylation (diazomethane) → GC‑MS (electron impact) with selected ion monitoring for quantification.
- Sensitivity: Method intended for concentrations ≥ 0.5 µg/L.
- Reagents & Safety: Use analytical‑grade solvents and high‑purity gases. Diazomethane preparation/use includes explicit safety warnings (explosive, toxic); handle in closed systems and fume hoods.
- Sorbents & Apparatus: SPE cartridges (e.g., styrene/divinylbenzene polymers), capillary GC columns, and MS capable of selected m/z quantification. Annexes list suitable columns and sorbents.
- Quality Control: Blanks, multipoint calibration with methylated standards, internal standards (e.g., dibromo/tribromo or deuterated analogues), recovery checks across concentration ranges, and batch‑consistency of sorbents.
- Interferences: Guidance on sample storage (≈4 °C), filtration for suspended matter, avoiding alcohols in injection solvents and removal of excess diazomethane to prevent instrument damage.
Applications & Users
- Environmental and public‑health laboratories performing water quality monitoring and compliance testing for nitrophenol contamination.
- Regulatory bodies and accredited testing labs that require standardized, comparable results for drinking, ground and surface water.
- Researchers studying nitrophenol occurrence, fate and transport in aquatic systems.
- Chemical manufacturers and environmental consultants who monitor effluent impact or remediation effectiveness (when testing relevant water types).
Related Standards
ISO 17495 references sampling and analytical practice standards:
Annexes (A–D) provide examples of suitable columns and sorbents, precision data and typical spectra to support method implementation.