Overview
ISO 6143:2001 - Gas analysis: Comparison methods for determining and checking the composition of calibration gas mixtures provides standardized, quantitative methods to determine and verify the composition of calibration gases by comparison with reference gas mixtures. It sets out procedures to calculate and report the measurement uncertainty of calibration gas compositions, validate calibration behaviour and compare multiple gas mixtures for consistency. The standard emphasizes traceability, use of mole fraction as the preferred composition unit, and proper treatment of uncertainty following internationally recognized frameworks.
Key topics and technical requirements
- Comparison methods: Determine analyte content by measuring instrumental response against known reference gases.
- Uncertainty evaluation: Calculate standard and expanded uncertainties of gas composition relative to the known uncertainties of reference mixtures (GUM-based approach).
- Calibration and analysis functions: Define and derive calibration (y = F(x)) and analysis (x = G(y)) functions; supports non-linear response models and regression techniques that account for errors in both variables.
- Calibration experiment design: Guidance on selecting calibration range, reference mixtures, number/sequence of measurements, instrument performance checks and validation.
- Validation and drift checks: Procedures to assess fit quality, validate analysis functions, check instrument stability and evaluate matrix effects when sample composition differs from reference gas matrices.
- Data evaluation and computer implementation: Annex A is normative for data evaluation methods; Annex C provides information on implementing calculations in software (computer-based computation needed for advanced regression and uncertainty propagation).
- Reporting: Requirements for test reports and documentation of results and uncertainties.
Applications
ISO 6143 is practical for any laboratory or organization that prepares, certifies, verifies or uses calibration gas mixtures:
- Manufacturers and suppliers of calibration gas mixtures
- National and industrial metrology laboratories
- Environmental monitoring and air quality laboratories
- Instrument manufacturers and analytical service providers performing gas analysis calibration
- Certification and conformity assessment bodies verifying gas mixture composition and traceability
Use cases include establishing traceable composition of working standards, validating preparation methods, comparing different production techniques, and checking consistency among batches.
Who should use it
Analytical chemists, metrologists, quality managers, gas producers and calibration labs needing rigorous, traceable procedures for calibration gas composition, uncertainty estimation and inter-comparison of gas mixtures.
Related standards and references
- Replaces aspects of ISO 6143 (first edition) and supersedes ISO 6711:1981 (as noted in the foreword)
- References international measurement guides such as GUM (Guide to the Expression of Uncertainty in Measurement), VIM (International Vocabulary of Metrology) and ISO Guide 30 for reference material concepts
Keywords: ISO 6143, gas analysis, calibration gas mixtures, comparison methods, measurement uncertainty, traceability, reference gas mixtures, calibration function, regression.