Overview
ISO 10980:1995 - Validation of the strength of reference solutions used for measuring concentrations - defines practical procedures for preparing, standardizing and validating the strength (concentration) of reference solutions. Published by ISO/TC 85 (Nuclear energy), this working standard is targeted at analytical chemists and laboratories that require traceability of solution strengths to basic units with a relative accuracy of ±0.1% or better. The standard simplifies the underlying statistical theory to make step‑by‑step laboratory implementation straightforward (see Annex H).
Key topics and requirements
- Scope and intent: Procedures to ensure quality and degree of accuracy of reference solution strengths used for concentration measurements, emphasizing traceability to certified materials and basic units.
- Primary vs Secondary reference solutions:
- Primary: prepared from certified reference materials with relative uncertainty ≤ 0.05% (95% confidence). Used to calibrate/check secondary solutions.
- Secondary: prepared from certified materials with precision between 0.05% and 0.2%, or from pure but uncertified materials standardized against primary solutions.
- Materials covered: Practical preparation and validation examples for uranium, plutonium and potassium dichromate reference solutions (Annexes A–C).
- Validation principle: Independently prepare solutions, calculate strength from precise weighing and certified composition, then verify by intercomparison (e.g., titration of one solution by another). The acceptable difference between calculated and measured strengths depends on measurement precision, number of replicates and chosen risks of false rejection (α) and non‑detection (β).
- Uncertainty and statistical checks: Guidance for estimating combined uncertainty from preparation, certification and analytical measurement; sample size rules and acceptance limits referenced (Annexes E–G contain numerical methods and examples).
- Reporting: A documented protocol of validation results is required (Annex H provides a template).
Applications
- Calibration and quality assurance of reference solutions used in analytical chemistry and nuclear fuel technology.
- Standardization of titrants (e.g., potassium dichromate) and gravimetrically prepared uranium/plutonium standards.
- Ensuring traceability of concentration measurements to certified reference materials and SI units.
- Laboratory method validation, routine QA/QC and inter‑laboratory comparisons.
Who should use ISO 10980:1995
- Analytical chemists and laboratory technicians preparing and standardizing reference solutions.
- Metrology and accreditation bodies responsible for traceability and measurement uncertainty.
- Nuclear fuel labs and organizations performing high‑precision uranium/plutonium assays.
- QA managers and auditors overseeing chemical standardization and calibration workflows.
Related standards
- ISO 7097 - (method referenced for uranium titration)
- ISO 8298 - (method referenced for plutonium titration)
- Other ISO and national standards on certified reference materials and uncertainty estimation
Keywords: ISO 10980:1995, validation of reference solutions, reference solution strength, analytical chemists, traceability, primary reference solutions, secondary reference solutions, titration standardization, uncertainty, calibration.
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