ISO 22309:2011

Overview

ISO 22309:2011 - "Microbeam analysis - Quantitative analysis using energy‑dispersive spectrometry (EDS) for elements with an atomic number of 11 (Na) or above" - is an international guidance standard for performing and reporting quantitative X‑ray microanalysis using EDS on scanning electron microscopes (SEM) and electron probe microanalysers (EPMA). It covers procedures for point and area analyses, element identification, data reduction and reporting, and addresses both reference‑material and “standardless” approaches for routine quantitative analyses down to about 1 % mass fraction (with careful cases to 0.1 %).

Key technical topics and requirements

• Scope and element range: Designed for elements with atomic number Z ≥ 11 (Na) and above; guidance on light elements (Z < 11) is provided but accurate quantitative EDS for these is not assured.
• Specimen preparation: Emphasis on flat, polished surfaces for best accuracy; non‑polished samples introduce additional uncertainty.
• Instrument considerations: Covers accelerating voltage, beam current and stability, live/dead time, and detector characteristics (including consideration of silicon drift detectors).
• Spectral processing: Peak identification, background subtraction, peak intensity estimation and handling of peak overlaps and escape peaks.
• Quantification methods: Calculation of k‑ratios, matrix corrections (absorption, fluorescence, atomic number corrections), use of reference materials (CRMs/RMs) vs standardless procedures, and limits of routine quantification (~1 % mass fraction).
• Uncertainty and quality: Guidance on factors affecting uncertainty, repeatability/reproducibility, and reporting requirements consistent with laboratory competence (e.g., ISO/IEC 17025).
• Complementary techniques: Notes that wavelength‑dispersive spectrometry (WDS) can help resolve low‑energy peak overlaps that limit EDS accuracy.

Practical applications and users

ISO 22309:2011 is intended for laboratories and professionals performing microbeam elemental analysis, including:

• Materials characterization and failure analysis teams
• Geological and mineralogical laboratories (e.g., silicate oxygen estimation strategies)
• Forensic and environmental testing labs
• Quality control in manufacturing (metals, ceramics, electronics)
• Instrument manufacturers and software developers implementing quantitative EDS workflows It helps users produce traceable, consistent quantitative results and to understand the limitations of EDS (especially for light elements and low concentration measurements).

Related standards

• ISO 14594 - EPMA guidelines for WDS parameters
• ISO 15632:2002 - Instrumental specification for EDS with semiconductor detectors
• ISO 16700 - SEM magnification calibration
• ISO/IEC 17025 - Competence of testing and calibration laboratories

Keywords: ISO 22309:2011, EDS quantitative analysis, microbeam analysis, SEM, EPMA, k‑ratio, matrix effects, standardless analysis, reference materials, light elements, silicon drift detector.