Overview
EN ISO 14911:1999 (ISO 14911:1998) specifies an ion chromatography (IC) method for the determination of dissolved cations Li+, Na+, NH4+, K+, Mn2+, Ca2+, Mg2+, Sr2+ and Ba2+ in water and waste water. The standard covers system requirements, sample pretreatment, eluents, calibration, interferences and quality checks for reliable quantification using conductivity detection (with or without a suppressor).
Key topics & technical requirements
- Scope: Applicable to drinking water, surface water and waste water; applicability to specific waste water samples must be verified.
- Analytical principle: Liquid chromatographic separation on a low-capacity cation-exchange column with conductivity detection; suppressor devices recommended to lower eluent conductivity and improve sensitivity.
- Essential minimum requirements:
- Column resolution R ≥ 1.3 for target peaks.
- Conductivity detection (with or without suppressor).
- Calibration across linear or quadratic ranges (see ISO 8466-1 / ISO 8466-2).
- Quality checks such as validation of calibration and replicate determinations.
- Working ranges (typical with 10 μl loop):
- Lithium: 0.01–1 mg/L
- Sodium, Ammonium, Potassium: 0.1–10 mg/L
- Manganese, Calcium, Magnesium, Strontium: 0.5–50 mg/L
- Barium: 1–100 mg/L
- Sample dilution or loop-size changes recommended to meet ranges.
- Interferences & sample care:
- Organics (amino acids, amines) and strong complexing agents can interfere.
- Cross-sensitivities (e.g., Zn, Ni, Cd) depend on column selectivity and suppression technique.
- Remove solids and oils/detergents/humic acids to protect column lifetime.
- Eluents & reagents: Examples given (HCl/DAP, methanesulfonic acid, tartaric acid/PDA, nitric acid eluents); eluents must be degassed and renewed periodically (examples: HCl/DAP every 7 days; methanesulfonic/tartaric eluents every 3 days).
- Standards for calibration & materials: Procedures for stock and mixed standards, storage conditions and titre adjustments are specified.
Applications & who uses it
- Routine monitoring of water quality in laboratories performing compliance testing for drinking water, surface water and industrial or municipal waste water.
- Environmental and research laboratories monitoring dissolved cations and trends in aqueous chemistry.
- Water utility and wastewater treatment operators for process control and regulatory reporting.
- Manufacturers of ion chromatography equipment and column suppliers for method validation and product guidance.
Related standards
- ISO 5667 series (sampling guidance)
- ISO 8466‑1 / ISO 8466‑2 (calibration and evaluation of analytical methods)
- ISO 6058 / 6059 / 7980 / 6333 (reference methods for Ca/Mg, Mn and titrimetric/absorption methods)
Keywords: EN ISO 14911:1999, ion chromatography, water quality, dissolved cations, Li+, Na+, NH4+, K+, Mn2+, Ca2+, Mg2+, Sr2+, Ba2+, conductivity detector, eluents, calibration.
