Overview
EN ISO 15682:2001 (identical to ISO 15682:2000) defines standardized procedures for the determination of chloride in water by automated flow analysis - both Continuous Flow Analysis (CFA) and Flow Injection Analysis (FIA) - with photometric or potentiometric detection. The methods cover chloride concentrations from 1 mg/l to 1 000 mg/l (with dilution for higher concentrations) and are intended for a broad range of matrices including ground, drinking, surface and waste waters, and leachates. Flow analysis methods are optimized for high throughput (up to ~100 samples/hour) and integration of sample preparation in the flow manifold.
Key topics and technical requirements
- Two detection options
- Photometric detection: chloride liberates thiocyanate which reacts with Fe(III) to form a red Fe(III)-thiocyanate complex; uses mercury(II) thiocyanate reagent (hazardous waste handling required).
- Potentiometric detection: uses ion-selective electrodes; suitable for turbid or coloured samples and is ecologically preferable because it avoids toxic reagents.
- Flow modes
- FIA: sample injected into a continuous carrier stream.
- CFA: sample delivered into carrier stream by pump (peristaltic).
- Analytical range and calibration
- Typical working range 1–1 000 mg/l; use at least five calibration standards per working range (examples for 1–10 mg/l and 10–100 mg/l shown in the standard).
- Interferences and sample prep
- Interference from bromide/iodide (bromide significant above ~30 mg/l); sulfide treated with hydrogen peroxide; colour or matrix absorbance compensated using parallel blank channel or dilution; filter samples with particles >100 µm; adjust pH to 3–10.
- Reagents and quality
- Use analytical-grade reagents and grade 1 water (ISO 3696). Reagent preparation and degassing procedures are specified. Tests must be performed by suitably qualified staff.
- Documentation
- Methods include performance characteristics, flow diagrams and guidance for single calibration functions (informative annexes).
Applications and users
- Environmental and public-health laboratories analyzing chloride in drinking water, groundwater, surface water, wastewater and landfill leachates.
- Routine monitoring programs, process control in water treatment plants, regulatory compliance testing, and high-throughput commercial testing labs.
- Useful for labs needing automated, repeatable chloride assays with options adapted to sample turbidity or ecological concerns.
Related standards
- ISO 3696 (Water for analytical laboratory use - specification and test methods) is normative for reagent-grade water.
- EN ISO 15682:2001 is the CEN adoption of ISO 15682:2000; consult national CEN bodies for implementation details.
Keywords: EN ISO 15682:2001, chloride determination, flow analysis, CFA, FIA, photometric detection, potentiometric detection, water quality, chloride in water, analytical method.