ISO 4717:2024

Overview

ISO 4717:2024 - Water quality - Protactinium 231 - Test method using ICP‑MS specifies a validated procedure for determining protactinium‑231 (231Pa) in water by inductively coupled plasma mass spectrometry (ICP‑MS). The standard covers sample types including drinking water, rainwater, surface and ground water, marine water, cooling and industrial waters, and domestic/industrial wastewater after appropriate sampling and preparation. Results reported as mass concentration can be converted to activity concentration; the method is designed to support routine monitoring, regulatory compliance and emergency response.

Key technical topics and requirements

• Analytical principle: Determination of 231Pa by ICP‑MS with options for pre‑concentration and chemical separation.
• Scope & measurement range: Designed for activity concentrations between 0.1 Bq·L−1 and 100 Bq·L−1. Higher concentrations can be measured after dilution.
• Limit of detection (LOD): Approximately 0.1 Bq·L−1 using current apparatus - aligned with the WHO guidance level for drinking water. LOD depends on sample volume, instrument performance, background count rate, detection efficiency and chemical yield.
• Sample handling: Filtration of test samples is necessary; analysis of 231Pa adsorbed to suspended solids and the insoluble fraction (which requires mineralization) is not covered.
• Separation & preparation: Chemical separation procedures (e.g., extraction chromatography, anion exchange) are provided in informative annexes to isolate Pa prior to ICP‑MS measurement.
• Quality control: Instrument verification, method verification, use of internal standards, tracer recovery assessment, background correction, and calculation of uncertainty (per ISO/IEC Guide 98‑3) are specified.
• Expression of results: Procedures to convert mass concentration to activity concentration, calculate chemical recovery and correct for tracer contamination are included.
• Reporting: Requirements for test reports and documentation to ensure traceability and comparability.

Practical applications and users

• Environmental and public‑health monitoring of radionuclides in water (drinking water compliance).
• Emergency response laboratories evaluating radiological contamination in water after incidents.
• Water utilities, nuclear facility effluent monitoring, and industrial sites needing routine radioactivity checks.
• Accredited testing laboratories (ISO/IEC 17025) and radiochemistry ICP‑MS laboratories implementing radionuclide analyses.

Keywords: ISO 4717:2024, protactinium 231, 231Pa, ICP‑MS, water quality, limit of detection, WHO guidance, radionuclide monitoring, extraction chromatography.

Related standards

• ISO 17294‑1:2024 and ISO 17294‑2:2023 (ICP‑MS application guidance)
• ISO 5667 series (water sampling and handling)
• ISO/IEC Guide 98‑3 (uncertainty of measurement)
• ISO/IEC 17025 (laboratory competence)
• ISO 80000‑10 (quantities and units - atomic and nuclear physics)

This standard provides laboratories with a practical, ISO‑aligned method for accurate 231Pa measurement by ICP‑MS to support regulatory compliance, public health protection and emergency preparedness.