ISO 15796:2005

Overview - ISO 15796:2005 (Gas analysis - Investigation and treatment of analytical bias)

ISO 15796:2005 provides generic, practical methods for detecting, quantifying and treating analytical bias (systematic error) in gas analysis. It focuses on using reference gas mixtures or reference analytical procedures to demonstrate traceability and either correct bias or account for it in the measurement uncertainty. The standard addresses the main bias sources: instrumental drift, matrix interferences, and the typical dependence of bias on analyte concentration. It is intended for use during method development and method validation.

Key topics and technical requirements

• Bias detection and correction approaches
  • Two options: (1) trace and model observed deviations and correct results, or (2) average effects and increase assigned uncertainty. Option (1) generally yields lower uncertainty but requires more effort.
• Instrumental drift
  • Procedures for stability monitoring using a drift-control mixture, control charts (Shewhart-style ±1, ±2, ±3 σ limits), and statistical trend tests based on successive differences.
  • Initial stability characterization: analyse the control mixture at least 10 times to estimate precision; update control limits only if the system remains stable.
  • Use of two distinct drift-correction mixtures to test concentration-invariance of drift and to derive pooled corrections when applicable.
• Matrix interferences and concentration dependence
  • Protocols for investigating bias as a function of sample matrix and analyte concentration and for handling local vs extended measuring ranges.
• Uncertainty estimation
  • Methods for estimating uncertainty associated with bias corrections and for increasing uncertainty when corrections are not applied.

Applications - who uses ISO 15796:2005

• Analytical laboratories performing gas composition analysis (environmental, industrial emissions, process control).
• Metrology and calibration laboratories that provide reference gas mixtures or reference procedures.
• Instrument manufacturers and method developers validating instruments and calibrations.
• Quality assurance/quality control (QA/QC) teams implementing traceability and uncertainty budgets.

Practical value and SEO keywords

ISO 15796:2005 helps organizations ensure traceable gas measurements, reduce systematic errors through drift correction, and document uncertainty when bias cannot be fully removed. Keywords: ISO 15796:2005, gas analysis, analytical bias, drift correction, reference gas mixtures, matrix interferences, traceability, stability monitoring, measurement uncertainty, method validation.

Related standards (if applicable)

• ISO 14111, ISO/TS 14167 (traceability principles for gas analysis)
• Guide to the Expression of Uncertainty in Measurement (GUM)
• ISO 7504 (gas analysis vocabulary)
• ISO 8258 (control chart tests)

This standard is a practical resource for establishing bias control and demonstrating traceability in gas analysis workflows.