Natural Matrix Reference Materials

This database was originally prepared as an information resource for participants in IAEA programmes in the area of nutritional and health-related environmental studies. The selection of the measurands and matrices of interest arose out of the specific needs of these programmes.

All the materials listed in the database are of natural origin, i.e. so called "matrix" or "compositional" reference materials. The database contains over 24,000 values (mass fraction or concentration) for 725 different measurands and 1751 reference materials produced by 57 producers from 22 countries.

Quality LevelExplanation of Terms

• Authoritative: All information in the resource has been verified by authorities as indicated.
• Quality-checked: All information in the resource has been quality-checked as indicated.
• Not quality-checked: Although the information in the resource may come from peer-reviewed journals or other high-quality sources, it has not undergone subsequent quality checking before incorporation in the resource.

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CompletenessExplanation of Terms

• Comprehensive:The resource includes all items in the category for which the resource was created.
• Selective: The resource includes only selected items in the category for which the resource was created, with the process or basis for the selection as indicated.

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Update FrequencyExplanation of Terms

• Updated continually: A conscientious effort is made to add new information immediately and keep the resource up-to-date on a day-by-day basis.
• Updated periodically: The resource is updated on a schedule. Common values are monthly, quarterly, annually or biennially, but others are also used.
• Updated occasionally: The resource is updated now and then, but not on a schedule.
• Static: The resource is a one-off creation with no plans for updates, or a resource that was updated in the past but has now been frozen with no new input planned.

: Updated occasionally