New ISO/TR 33402:2025 on Reference Material Preparation

The International Organization for Standardization (ISO) has published ISO/TR 33402:2025 "Good practice in reference material preparation" (Edition 1, Publication Date: January 2025). This new technical report provides guidance on best practices in the preparation of reference materials (RMs). It was developed by Technical Committee ISO/TC 334, Reference Materials, and replaces ISO Guide 80:2014.

Reference Materials (RMs)

Reference materials are essential for ensuring accuracy, reliability, and comparability in analytical measurements. Laboratories use them for method validation, calibration, and quality control.

The new ISO/TR 33402:2025 outlines the key steps in preparing candidate matrix reference materials (RMs), including:

• Defining material specifications,
• sourcing and selecting bulk material, and
• processing the material.

These steps are crucial for producing reliable matrix RMs. The new report expands on ISO Guide 80:2014, which primarily focused on statistical quality control materials. In contrast, ISO/TR 33402:2025 covers a broader range of matrix reference materials, applicable across multiple industries and scientific fields.

Content

The 41-page document is structured as follows:

• Foreword
• Introduction
• 1. Scope
• 2. Normative references
• 3. Terms and definitions
• 4. Overview of preparation of candidate reference materials (RMs)
• 5. Material specification
• 6. Sourcing and selection of bulk material
• 7. Material processing
• Annex A. Case study 1 — Production of a quality control material (QCM) from coal
• Annex B. Case study 2 — Production of geological or metallurgical quality control materials (QCMs)
• Annex C. Case study 3 — Production of a wheat flour fortified with folic acid quality control material (QCM)
• Annex D. Case study 4 — Bauxite quality control material (QCM)
• Annex E. Case study 5 — Pharmaceutical reference standards
• Annex F. Case study 6 — Production of testing materials for “bromate in water”
• Bibliography

Target Groups and Availability

The document serves as a practical guide for laboratory staff involved in preparing and using matrix reference materials for specific applications. Additionally, reference material producers (RMPs) can use it as a resource for RM preparation.

The annexes (A–F) provide case studies, illustrating RM preparation in different fields. While these are not full production manuals, they highlight key considerations in the preparation process.

ISO/TR 33402:2025 can be purchased from DIN Media or ISO. A read sample is available on the ISO Online Browsing Platform (OBP).