Overview
EN ISO 17495:2003 / ISO 17495:2001 specifies an analytical method for the determination of selected nitrophenols in drinking, ground and surface water at mass concentrations down to 0.5 µg/L. The method combines solid‑phase extraction (SPE) for preconcentration, derivatization with diazomethane, and analysis by gas chromatography with mass spectrometric detection (GC‑MS). The standard was adopted by CEN as EN ISO 17495:2003 and is intended for routine and investigative water‑quality monitoring.
Key topics and technical requirements
- Scope of analytes: Applicable to a range of nitrophenols (e.g., 2‑, 3‑, 4‑nitrophenol and various methylated, dinitro and chloro‑substituted nitrophenols). (See Table 1 in the standard for CAS numbers.)
- Sample types and detection limit: Drinking, ground and surface waters; target mass concentration ≥ 0.5 µg/L.
- Preconcentration: Solid‑phase extraction from acidified samples; choice and batch consistency of sorbent is critical (Annex B lists suitable sorbents).
- Derivatization: Methylation with diazomethane (prepared from precursors such as Diazald) to form methylated derivatives suitable for GC‑MS.
- Analysis: GC‑MS for separation and identification; calibration and statistical evaluation per ISO 8466‑1.
- Quality control: Regular blank checks, recovery checks at different concentrations, single‑batch sorbent use for calibration and analysis, and precision data provided in Annex C.
- Interferences and handling:
- Sorbent batch variability and suspended solids can affect recoveries; filtration may be required and must be reported.
- Avoid alcohol solvents that can damage GC inlet liners/deactivation layers.
- Remove excess diazomethane and use a keeper (e.g., iso‑octane) to prevent losses during concentration.
- Reagents and gases: High‑purity water and carrier gases; specified solvents (ethyl acetate, acetone, diethyl ether stabilized with ethanol), acids/bases for pH control.
Applications and practical use
- Environmental monitoring and compliance testing for nitrophenol contaminants in potable and surface waters.
- Pollution incident investigation and source tracking where nitrophenolic compounds are suspected.
- Laboratory method implementation: establishes SPE‑GC‑MS workflows, QC requirements, and calibration procedures for contract labs and utilities.
- Research and risk assessment: reliable quantitative data for exposure and fate studies of nitrophenols.
Who should use this standard
- Environmental analytical laboratories, water utilities, regulatory agencies, public health laboratories, and researchers performing SPE‑GC‑MS analysis of phenolic pollutants.
Related standards
- ISO 5667 series (sampling guidance: parts 1, 2, 3) - sampling, preservation and handling.
- ISO 8466‑1 - calibration and statistical evaluation of analytical methods.
Safety note: the standard warns about diazomethane hazards and general laboratory safety; users must follow appropriate health and safety practices.