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National Measurement Institute

Certified Reference Materials

CRMs Explained

Certified reference materials (CRMs) play a critical role in quality assurance and contribute to the process of establishing traceability of units used to report laboratory results. The use of appropriate CRMs is an important aspect of accreditation to ISO/IEC 17025.

The highest level measurement benchmarks are provided by CRMs. CRMs are a specific class of reference material whose property values (purity, concentration etc) are established and certified in accordance with metrological principles using established, international best practice protocols. CRMs can be pure chemical substances, blends or synthetic mixtures, and spiked or naturally occurring matrices.

CRMs are used to calibrate the measurement process and they all have common characteristics:

  • assigned values are accompanied by an uncertainty statement
  • information is given on the methods used to assign values
  • the intended use of the CRM is described
  • the reported values of CRMs are, by definition, traceable to accurate realisations of the units in which they are expressed

Appropriate use of CRMs will help you to assess the accuracy of your analysis and to establish the traceability of test results to national or international standards.

NMI has NATA accreditation for reference material production for chemical reference materials and reference gas mixtures and complies with ISO Guide 34 General Requirements for the Competence of Reference Material Producers.

The following criteria apply to NMI's CRMs which are detailed at the bottom of this page:

  • compound identity is confirmed by a minimum of two spectroscopic techniques including NMR (1H, 13C), GC–MS, LC–MS and FT–IR
  • purity is assessed using a minimum of two techniques including GC–FID, HPLC, TGA, DSC, quantitative 1H NMR and elemental microanalysis
  • the characterisation data for each compound are assessed by an independent scientific review panel as the final step in the certification process
  • a comprehensive analytical report is provided with each compound and full details of chromatographic and spectral data are available on request

Click here for information on:

  • DNA reference materials — NMI is able to design, prepare and characterise DNA reference materials for specific applications. They may be provided in solution or pre-dispensed in client-defined quantities into wells of a PCR plate.
  • Chemical reference materials for quality control and method validation — surplus reference materials from our interlaboratory proficiency testing program are available for purchase. All samples are homogeneous and have been well characterised. However they have not been produced or certified in strict accordance with ISO Guides 30 to 35 and so are not CRMs; in particular, long-term storage stability has not been assessed.

For further information contact, +61 2 9449 0191 or use our on-line form.