Overview
EN ISO 14402:1999 - Water quality: Determination of phenol index by flow analysis (FIA and CFA) specifies two automatic flow-analysis methods for measuring the phenol index in waters (ground, surface, seep and waste waters). The standard covers both flow injection analysis (FIA) and continuous flow analysis (CFA) approaches and is intended for mass concentrations from 0.01 mg/L to 1.0 mg/L in undiluted samples. It describes method principles, reagents, apparatus, sampling, procedures, calculation, precision and reporting.
Key topics and technical requirements
- Two methods
- Phenol index without distillation after solvent extraction (clause 3).
- Phenol index without extraction after distillation (clause 4).
- Analytical principle (extraction method)
- Oxidation by potassium peroxodisulfate, reaction with 4‑aminoantipyrine forming coloured products, solvent extraction into chloroform, and spectrometric detection (470–475 nm).
- Reagents and calibration
- Specifies reagent grades (water per ISO 3696), preparation of buffer, 4‑aminoantipyrine and oxidant solutions, phenol stock/standards and daily calibration (minimum five calibration points per range).
- Apparatus
- Detailed flow manifold components for FIA and CFA: pumps, injectors/autosamplers, reaction coils, extraction cell with phase separator (e.g., PTFE membrane), flow spectrometer (typical pathlength ~10 mm) and recording system.
- Interferences & sample handling
- Chemical interferences (e.g., aromatic amines), pH effects (reaction pH must be controlled), physical issues with particulates, coloured samples, and detergents (can disturb phase separation or distillation).
- Quality aspects
- Requirements for degassed solutions, reagent blank checks, precision/accuracy data and a specified test report format. Safety warning: phenol and chloroform are toxic - handle and dispose appropriately.
Applications and users
- Routine environmental monitoring of phenolic compounds in surface water, groundwater and wastewater.
- High‑throughput laboratories using automated FIA/CFA instrumentation for continuous sample series.
- Users: accredited water testing labs, environmental agencies, wastewater utilities, instrument manufacturers and consultancy labs performing regulatory compliance or process control analyses.
Related standards
- ISO 6439 - Phenol index: 4‑aminoantipyrine spectrometric methods after distillation.
- ISO 3696 - Water for analytical laboratory use.
- ISO 5667-3 - Sampling: guidance on sample handling and preservation.
Keywords: EN ISO 14402:1999, phenol index, flow analysis, FIA, CFA, water quality, 4‑aminoantipyrine, chloroform extraction, environmental monitoring.