Certified reference materials

reference materialsreference materialStandard Reference Materialcertified reference material
Certified Reference Materials (CRMs) are ‘controls’ or standards used to check the quality and metrological traceability of products, to validate analytical measurement methods, or for the calibration of instruments.wikipedia
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Calibration

calibratedcalibratecalibrating
Certified Reference Materials (CRMs) are ‘controls’ or standards used to check the quality and metrological traceability of products, to validate analytical measurement methods, or for the calibration of instruments. Quality management systems involving laboratory accreditation under national and international accreditation/certification standards such as ISO/IEC 17025 require metrological traceability to Certified Reference Materials (where possible) when using reference materials for calibration.
Establishing traceability is accomplished by a formal comparison to a standard which is directly or indirectly related to national standards (such as NIST in the USA), international standards, or certified reference materials.

Standard (metrology)

standardstandardsmetrology standard
A certified reference material is a particular form of measurement standard.
Working standards and certified reference materials used in commerce and industry have a traceable relationship to the secondary and primary standards.

Canadian Reference Materials

Canadian Reference Material
Canadian Reference Materials (CRM) are certified reference materials of high-quality and reliability produced by the National Metrology Institute of Canada – the National Research Council Canada.

GeoReM

GeoReM (Geological and Environmental Reference Materials), a database of reference materials of geological and environmental interest, is accessible to the scientific community on the internet.

Metrology

metrologicalmetrologistlegal metrology
Certified Reference Materials (CRMs) are ‘controls’ or standards used to check the quality and metrological traceability of products, to validate analytical measurement methods, or for the calibration of instruments. Quality management systems involving laboratory accreditation under national and international accreditation/certification standards such as ISO/IEC 17025 require metrological traceability to Certified Reference Materials (where possible) when using reference materials for calibration.

Quality management system

quality systemQuality Management SystemsQuality Systems
Quality management systems involving laboratory accreditation under national and international accreditation/certification standards such as ISO/IEC 17025 require metrological traceability to Certified Reference Materials (where possible) when using reference materials for calibration.

International standard

international standardsstandardstandards
Quality management systems involving laboratory accreditation under national and international accreditation/certification standards such as ISO/IEC 17025 require metrological traceability to Certified Reference Materials (where possible) when using reference materials for calibration.

ISO/IEC 17025

ISO 17025ISO/IEC 17025:2005(ISO/IEC 17025:2000
Quality management systems involving laboratory accreditation under national and international accreditation/certification standards such as ISO/IEC 17025 require metrological traceability to Certified Reference Materials (where possible) when using reference materials for calibration.

United States

AmericanU.S.USA
The United States National Institute of Standards and Technology (NIST) uses the trade marked term Standard Reference Material (SRM) to denote a certified reference material that satisfies additional NIST-specific criteria.

National Institute of Standards and Technology

NISTNational Bureau of StandardsBureau of Standards
The United States National Institute of Standards and Technology (NIST) uses the trade marked term Standard Reference Material (SRM) to denote a certified reference material that satisfies additional NIST-specific criteria. Due to the difficulty in production and value assignment, these are usually produced by national or transnational metrology institutes like NIST (USA), BAM (Germany), KRISS (Korea) and EC JRC ( European Commission Joint Research Centre).

Federal Institute for Materials Research and Testing

Bundesanstalt für Materialforschung und -prüfungBAMFederal Institute for Materials Research
Due to the difficulty in production and value assignment, these are usually produced by national or transnational metrology institutes like NIST (USA), BAM (Germany), KRISS (Korea) and EC JRC ( European Commission Joint Research Centre).

Korea Research Institute of Standards and Science

KRISS
Due to the difficulty in production and value assignment, these are usually produced by national or transnational metrology institutes like NIST (USA), BAM (Germany), KRISS (Korea) and EC JRC ( European Commission Joint Research Centre).

Joint Research Centre

Joint Research Centre (European Commission)Directorate-General of the Joint Research Centre (European Commission)European Commission Joint Research Centre
Due to the difficulty in production and value assignment, these are usually produced by national or transnational metrology institutes like NIST (USA), BAM (Germany), KRISS (Korea) and EC JRC ( European Commission Joint Research Centre).

Antioxidant

antioxidantsanti-oxidantantioxidative
For example, stabilizing agents such as antioxidants or antimicrobial agents may be added to prevent degradation, liquids containing certified concentrations of trace metals may have pH adjusted to keep metals in solution, and clinical reference materials may be freeze-dried for long term storage if they can be reconstituted successfully.

Antimicrobial

anti-microbialantimicrobialsantimicrobial agent
For example, stabilizing agents such as antioxidants or antimicrobial agents may be added to prevent degradation, liquids containing certified concentrations of trace metals may have pH adjusted to keep metals in solution, and clinical reference materials may be freeze-dried for long term storage if they can be reconstituted successfully.

PH

pH levelneutralpH value
For example, stabilizing agents such as antioxidants or antimicrobial agents may be added to prevent degradation, liquids containing certified concentrations of trace metals may have pH adjusted to keep metals in solution, and clinical reference materials may be freeze-dried for long term storage if they can be reconstituted successfully.

Stratified sampling

stratificationstratifiedstratified random sampling
Typically 10-30 CRM units are taken from the batch at random; stratified random sampling is recommended so that the selected units are spread across the batch.

Blocking (statistics)

Randomized block designblockingblocks
Other designs, such as randomized block designs, have also been used for CRM certification.

Statistical hypothesis testing

hypothesis testingstatistical teststatistical tests
Data processing for homogeneity tests usually involves a statistical significance test for evidence of differences between units of the candidate CRM.

F-test

F''-testF testF-statistic
For the simple balanced design above, this typically uses an F test following ANOVA.

Analysis of variance

ANOVAanalysis of variance (ANOVA)corrected the means
For the simple balanced design above, this typically uses an F test following ANOVA.

Linear regression

regression coefficientmultiple linear regressionregression
The results are usually assessed by inspection and by linear regression to determine whether there is a significant change in measured value over time.