ISO/TS 15923-2:2017

Overview

ISO/TS 15923-2:2017 specifies automated photometric methods for the determination of selected water-quality parameters using a discrete analysis system. Covered analytes include chromium(VI), fluoride, total alkalinity, total hardness, calcium, magnesium, iron (total and Fe(II)), manganese and aluminium. The techniques are applicable to a broad range of water matrices - ground, potable, surface, waste, eluates and boiler water - and can be extended to marine waters with matrix-matched standards.

Key topics and technical requirements

• Measurement principle: colour-forming reagent chemistry in individual reaction cells (cuvettes) with incubation and photometric absorbance reading.
• Discrete analysis system: automated sample/reagent pipetting, incubator, visible-wavelength detector (approx. 400–880 nm), control/data unit and recording software.
• Sample preparation: filtration (recommended 0.45 µm) to remove particulates; settlement, centrifugation or dialysis also acceptable. Note that particulate-associated metals may not be quantified after filtration.
• Interferences & corrections: inherent sample colour and turbidity can affect photometry; Annex A provides colour-correction procedures. Specific interference discussions are given in annexes for each analyte (B–J).
• Reagents and standards: use analytical-grade reagents; primary calibration and control standards are described in the annexes. Commercial preparations may be used if stability/storage instructions followed.
• Calibration & quality control: establish calibration functions per ISO 8466-1/2; perform calibration verification regularly (recommend control standard at least every 20 samples) and use water-for-analytical-grade (ISO 3696) as blank.
• Limitations & scope: best suited for dissolved metals following on-site filtration; acid digestion procedures can be used only if they do not exceed the reaction mixture buffering capacity (digestion procedures themselves are beyond the scope).

Applications and users

• Environmental and public-health laboratories performing routine water-monitoring and compliance testing.
• Drinking-water utilities, wastewater treatment plants and industrial boiler/wastewater monitoring programs.
• Field laboratories and contract testing services that use automated discrete photometric analyzers.
• Manufacturers and integrators of discrete analysis systems developing methods or instrument-specific protocols.
• Researchers needing standardized, inter-comparable analytical procedures for water quality studies.

Related standards

• ISO 3696 - Water for analytical laboratory use
• ISO 8466-1 / ISO 8466-2 - Calibration and evaluation of analytical methods
• ISO 5667-3 - Sampling and sample handling guidance
• ISO 18412, ISO 23913 - Guidance referenced for chromium(VI) sample storage
• Other parts of the ISO 15923 series covering discrete photometric determinations

Keywords: ISO/TS 15923-2:2017, water quality, discrete analysis system, photometric detection, chromium(VI), fluoride, alkalinity, hardness, calcium, magnesium, iron, manganese, aluminium, calibration, sample filtration.