FAQ

  1. How should I use the data obtained on measurements of a CRM?
    30/04/2014

    There are different possibilities to use the data obtained on a measurement of a CRM. It can be used to help to:

    • validate a method of measurement. This is to see, if the observed value and the certified value match within the uncertainty.
    • verify a specific measurement procedure. This is to see, if the observed value and the certified value match within the uncertainty under the specific laboratory conditions.
    • control the accuracy of measurements within the uncertainty.
    • calibrate a measurement device for a specific type of measurement. This is to establish the relation between a ‘signal’ and the quantity intended to be measured (usually a concentration). In the simple case, a calibration factor and its uncertainty is calculated from the observed value and the certified value.
    • establish proficiency testing. The use of a well characterised (i.e. certified) material in form of a ‘blind sample’ is advantageous, in order to monitoring against a stated reference, in particular the inalterable SI being stable in time and space.
    • develop new methods of measurement.
    • estimate measurement uncertainty.
    Institutes: IRMM
    Keywords: reference material, measurement, quality, standard
  2. How reliable is my measurement result?
    30/04/2014

    The reliability of the method applied has to be demonstrated by means such as method validation, proper use of quality assurance tools (including the use of CRMs) and the participation in proficiency testing.

    Institutes: IRMM
    Keywords: reference material, measurement, quality, standard
  3. Which value do I use for calibration?
    30/04/2014

    The value mentioned on the certificate is the certified value for the reference material and consequently the value to be used for calibration. But the uncertainty of the certified value has also to be included for the estimation of the measurement uncertainty.

    Institutes: IRMM
    Keywords: reference material, measurement, quality, standard
  4. How do I know whether the certified value is valid for my method?
    30/04/2014

    There are two CRM properties that describe the usefulness of a material for a certain method, namely traceability and commutability. Traceability describes what the certified value actually refers to including the definition of the measurand: is it about total or extractable element content, Kjeldahl or Dumans N? Commutability describes whether a material behaves similarly as a certain routine sample for a given method.

    Therefore, one should check whether the certified value of a CRM is traceable to the same reference as one’s method. If this is not the case, the material is unsuitable.

    Example: Certified values for dietary fibre traceable to a certain ISO method are only valid, if exactly this method is used.

    Additionally, one should check whether commutability is ensured. If this is not the case, the material may be unsuitable.

    Institutes: IRMM
    Keywords: reference material, measurement, quality, standard
  5. Which method do I have to use?
    30/04/2014

    Any method that is traceable to the same reference as the certified value can be used.

    Institutes: IRMM
    Keywords: reference material, measurement, quality, standard
  6. Where can I get additional information on my material?
    30/04/2014

    IRMM publishes for each material an extensive report available on this web site. This report gives valuable information on methods used by the participants and potential problems besides giving more detailed information on the production of the material.

    Institutes: IRMM
    Keywords: reference material, measurement, quality, standard
  7. Is the ERM® concept a closed club?
    30/04/2014

    ERM® is not a closed club, but explicitly open to new members, who fulfil the defined membership criteria as given at the ERM web site. The criteria are in brief:

    Be located within the European Union and be a signatory or designated laboratory of the CIPM-MRA.

    • Be a producer of certified reference materials who fulfils agreed quality standards,
    • in particular by having in place a quality system for the production of CRMs in accordance with ISO Guide 34 and 35.
    • Accept all principles of the ERM® Memorandum of Understanding.

    The three ‘founding’ partners of ERM® (BAM, IRMM, LGC) understand their role as being a nucleus.

    Institutes: IRMM
    Keywords: reference material, measurement, quality, standard
  8. What is an ERM® -branded material?
    30/04/2014

    An ERM is a CRM with the added value that very stringent quality criteria regarding production, homogeneity and stability testing, and of course characterisation measurements, have to be fulfilled. A special panel made up of leading experts in the field scrutinises every application before the ERM ® label is granted.

    Institutes: IRMM
    Keywords: reference material, measurement, quality, standard
  9. Are ERM® materials only for Europeans?
    30/04/2014

    No. ERM-CRMs are suitable for any user who requires reference materials of the highest level of assurance. ERM® materials are available from a number of reference material distributors who make them available worldwide. But membership of reference materials producers in the ERM® co-operation is open only to producers located in the European Union, who can demonstrate that they meet certain defined membership criteria. Materials marketed under the ERM® brand have been produced in accordance with the principles laid down in ISO Guides 34 and 35 and have been subject to extensive review by all member organisations.

    Institutes: IRMM
    Keywords: reference material, measurement, quality, standard
  10. Who owns the trademark?
    30/04/2014

    The European Community owns the ERM® trademark. The Community licences the trademark to the ERM® partner organisations to mark products accepted as ERM® in accordance with the ERM® rules.

    Institutes: IRMM
    Keywords: reference material, measurement, quality, standard