1) What is the difference between reference material certified reference material?
Reference materials is the general name given to pure or matrix materials used for material calibration, method validation, metrological traceability, quality control studies (proficiency testing, quality control cards).
For the reference material to be a Certified Reference Material (CRM), metrological traceability must be provided for the values and ambiguities to be assigned using proven homogeneity and stability, and validated methods for the characterization of the material. All the information obtained for the CRMs is presented to the customers with a certificate.
Metrological traceability and uncertainty information are mandatory for the assigned values of CRMs.
In order to check the accuracy of the results obtained by the applied measurement method (Trueness Check) and to provide metrological traceability, CRMs should be used.
You can distinguish reference materials produced by TÜBİTAK UME and certified reference materials from product codes. Certified reference materials are offered for sale with CRM code (UME CRM 1234) and reference materials with RM code (UME RM 1234).
While the CRMs produced by TÜBİTAK UME are presented with the Certification and Certification Report documents, the Reference Materials (Non-Certified) are presented with the Material Information Form.
2) What are the most common Reference Materials / Certified Reference Material (CRM) types?
i. Calibrator CRMs (pure materials): characterized for chemical purity and / or trace amounts of impurities. They are used for calibration purposes.
ii. Standard Solvents and Gas Mixtures: They are prepared from pure materials by gravimetrical mixing. They are used for calibration purposes.
iii. Matrix CRMs (analyte in the matrix): Characterized for major, minor and/or trace amount of chemical constituents. Prepared from a matrix having the constituent or addition of constituents to the matrix or preparation of a synthetic matrix with major matrix components. Used for method development, validation and quality control purposes.
iv. Physico-Chemical CRMs: Characterized for properties such as melting point, viscosity and density.
v.Reference objects or Human made artefacts: They are characterized for functional properties such as taste, smell, hardness. Microscopy samples characterized for microbiological properties or samples characterized for fiber type are also belong to this group.
3) What do you need to pay attention to in order to select the proper reference material?
Intended use of the material should be clearly defined:
Either the usage is for calibration (Pure materials or solutions) or quality control measurement (Matrix materials) should be clarified.
Observe the measurand and range:
Do you measure the extractable lead or total lead in your sample? You should choose a suitable material for your method.
A CRM with a certificated value that is lower than the method limit of your method is not suitable for you.
Matrix matching and potential interferences should be considered:
Care should be taken when the matrices are different, such as lead analysis in drinking water and lead analysis in serum are very different.
You should try to select the reference material that most closely resembles the routine samples that you measure in your laboratory. For example, in food analyzes, care should be taken to ensure that the fat content of the reference material is not very different than fat content of your routine samples .
The competence of the reference material manufacturer should be observed:
Does the manufacturer have ISO Guide 34 or ISO 17034 accreditation? Does it perform its activities in accordance with the requirements set out in these documents?
Laboratories involved in certification studies should also be assessed for ISO / IEC 17025 accreditations or CIPM MRA CMCs (Calibration and Measurement Capabilities).
It should be checked whether the information about the reference materials is mentioned clearly and transparently whether it is accessable or not:
The manufacturer should share the documents related to the reference materials (Certificate, Certification Report, Material Information Form) and it should be questioned whether access to these documents is easy.
Accessibility and price of reference material:
Can the material be reached as quickly as possible to the customer under defined conditions ? (e.g: In dry Ice: < -70 °C)
Feedback About Purchased Reference Material
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