Methods for Validating Reference Materials

Reference materials are used widely across scientific fields to ensure the accuracy and reliability of analytical results. However, how can we be sure that the reference materials used are an accurate standard to measure results against? Because they themselves need validation. Validating reference materials is a critical part of analytical chemistry as it will ensure analytical results are accurate and can be measured reliably. In this blog post, we will look at methods for validating reference materials, with a focus on fused calibration beads and synthetic ion ore materials.

Validating Reference Materials

The validation process of reference materials involves several stages but is ultimately guided by metrological traceability. The metrological traceability of a material relates to the original source and pieces used in production and the distribution and whereabouts of the material since. As defined by NIST: ‘Metrological traceability requires the establishment of an unbroken chain of calibrations to specified reference measurement standards: typically national or international standards, in particular realizations of the measurement units of the International System of Units (SI).’ The importance of traceability means that results (or measurements) can be compared by different researchers in different laboratories worldwide and can be clearly understood. However, the results must be supported by a documented and unbroken series of calibrations that refer to the original standard.

Reference materials can be validated by meeting specific ISO requirements, and they must be produced by a certified reference material manufacturer. Materials can be validated against a certified reference material (CRM) as they provide the highest level of accuracy and traceability to an SI unit of measurement. The final step in the chain is to measure a reference material to national metrology standards, for example, NIST, as this will provide the utmost accuracy and traceability. 

Validating a reference material involves testing its content, homogeneity, identity, purity, stability, and traceability to determine its suitability for its intended applications.  Researchers must be confident that the materials and test methods are accurate and precise. Validating reference materials involves taking samples from different batches to analyze and verify their stability over time. These results must be compared with certified values and monitored to ensure there are no major changes over time. 

XRF Scientific and Reference Materials

XRF Scientific develops chemicals and equipment for a range of commercial analytical laboratories, construction material companies, and production mines for use in sample preparation analysis. Our technology is designed to measure the purity of materials for quality and process control purposes and to help improve product quality and performance.

Fused Calibration Beads

One reference material commonly used to calibrate X-ray fluorescence (XRF) instruments is fused calibration beads. These beads are produced by melting several elemental oxides into a homogeneous glass matrix and can be customized for specific applications.

Multiple tests must be conducted with an XRF instrument to validate fused calibration beads to compare values obtained to the certified values of the beads. This process must be performed with beads from several batches to ensure accuracy.

Ion Ore Reference Materials

Iron ore reference materials are used to calibrate XRF instruments. These materials are produced with a matrix material and a specific quantity of the element being tested, which results in a homogenous sample.

Validating ion ore reference materials requires scientists to compare measured values from the ICP-MS instrument with certified values. This analysis must be conducted on multiple batches so that accuracy is ensured.

Contact a member of XRF Scientific today to learn more about the importance of validating reference materials and how we can support you with the process.