Certified reference material CRM

Many of these are also available as BCS Certified Reference Materials (CRM) supplied by the Bureau of Analysed Samples Ltd, Newham Hall, Middles borough, UK, who also supply EURONORM Certified Reference Materials (ERCM), the composition of which is specified on the basis of results obtained by a number of laboratories within the EEC. BCS Reference Materials are obtainable from the Community Bureau of Reference, Brussels, Belgium. In the USA similar reference materials are supplied by the National Bureau of Standards. 

In geochemistry, the introduction of RMs did not take place until 1951 but, once RM usage became a regular part of geochemical analysis, the consequences were not far short of amazing. For many years geochemical analysts had been concerned about the accuracy of their determinations of major elements in rocks, but it was the potential of emission spectrometry for the determination of trace elements which set off the production of the first rock Certified Reference Materials (CRMs),... 

The definition of a certified reference material (CRM) is given in ISO Guide 30 (1992) and it forms the root of all other ISO Guides ... 

Morabito R, Muntau H, Cofino W, Quevauviller Ph 1999) A new mussel certified reference material (CRM 477) for the quality control of butyltin determination in the marine environment. J Environ Monit 1 75-82. 

Quevauviller Ph, Maier EA, Vercoutere K, Muntau H, Griepink B (1992a) Certified reference material (CRM 397) for the quality control of trace element analysis of human hair. Fresenius J Anal Chem 343 335-338. 

Quevauviller Ph, Vercoutere K, Griepink B (1992b) Certified reference materials (CRMs 398 and 399) for the quality control of major element determination in freshwater. Mikrochim Acta 108 195-204. 

Certified reference materials (CRMs) to validate measurements of organic constituents were introduced in the early 1980 s, more than a decade after the development of the first natural matrix CRMs for inorganic constituents. There are three types of CRMs to support measurements of organic constituents ... 

Quevauviller Ph, and Maier EA (1999) Interlaboratory studies and certified reference materials for environmental analysis - the BCR approach. Elsevier, Amsterdam Quevauviller Ph, Drabaek I, Muntau H, Biahchi M, Bortoli A, and Griepink B (1996a) Certified reference materials (CRMs 463 and 464) for the quafity control of total and methyl mercury determination in tuna fish. Trends Anal Chem 15 160-167. 

Although the work of ATCC and others has done much to ensure the reproducibility and even demonstrate some traceability of microbiological reference materials the development of microbiological Certified Reference Materials (CRMs), certified for number of viable life forms is seen as important for control analyses of water and food. Somewhat of a holy grail the development of such CRMs has long been hampered by the unstable concentration and insufficient homogeneity of viable organisms in the materials. 

Primary reference materials, i.e. international or national certified reference materials, CRMs)... 

There is an abundance of references defining and describing the role played by QA, Quality Control (QC) and Total Quality Management (TQM) in a modem commercial analytical laboratory. The role played by reference materials (RMs) and certified reference materials (CRMs) in the pursuit of analytical measurement accuracy is also well documented. 

The Promochem Group was the first international specialist supplier of certified reference materials (CRMs) and pharmaceutical reference substances used in environmental, medical and trace element analysis. Their experience provides a viewpoint that echoes, reinforces and expands on many of the trends discussed above (Jenks 1997). From the middle of the 1980 s, sales of CRM by Promochem increased between 10 % and 20 % annually, depending on the market sector and application. Since then National and International Metrology Institutes, such as the now privatized U.K. Laboratory of the Government Chemist (LGC), the European and U.S. Pharmacopoeias, the E.U. IRMM and others have recognized that efficient distribution of RMs, backed by available technical support, is as important as production and certification. Thus, they have moved to spread their influence outside their national origins. The Web and e-commerce will continue to grow as major facilitators of better information dissemination and supply of CRMs. 

Quality assurance considerations lead to the need for appropriate reference materials, and their consistent and effective use to monitor the precision and accuracy of laboratory analyses. In this context, certified reference materials (CRMs), now still largely lacking in the polymer/additive area, play an important role. In previous years, some attempts have been undertaken to prepare some inorganic CRMs (VDA and PERM projects), but this is highly insufficient when we consider that some 60 elements are used in polymer/additive formulations. The lack of CRMs for organic compounds in polymeric matrices is an even more serious handicap. Nagoumey and Madan [122] have demonstrated that intermediate or finished in-house materials can be utilised successfully as QA reference materials. Good QC of polymer/additive formulations as yet has not been achieved. 

In analytical practice, they are best recognized by the determination of xtest as a function of the true value xtrue, and thus, by analysis of certified reference materials (CRMs). If such standards are not available the use of an independent analytical method or a balancing study may provide information on systematic errors (Doerffel et al. [1994] Kaiser [1971]). In simple cases, it may be possible, to estimate the parameters a, / , and y, in Eq. (4.5) by eliminating the unknown true value through appropriate variation of the weight of the test portions or standard additions to the test sample. But in the framework of quality assurance, the use of reference materials is indispensable for validation of analytical methods. 

Provided the sample matrix and analyte concentration are appropriate, matrix Certified Reference Materials (CRMs) can make ideal proficiency testing samples. The assigned value is the certified value given on the certificate accompanying the CRM. The certificate will also give an uncertainty estimate for the certified value, and the use of CRMs allows the traceability of analytical data to be established. However, matrix CRM availability is limited and the materials are often expensive. Hence, Certified Reference Materials are seldom used as PT samples. 

Eight Certified Reference Materials (CRMs) (Table 1) were analyzed, in triplicate random order, for 53 elements by five digestion protocols (Table 2) as shown in the experimental design (Table 3). All final determinations were by ICP-AES and -MS in a single batch using a randomized ordering of the prepared digestions. 

Do you use Certified Reference Materials (CRMs), and if so, how For example, specify the concentrations) matrix type(s) etc. 

Certified Reference Materials (CRM) should provide traceable values (to... 

The certified reference material (CRM 450), used for the validation of the method, is real contaminated powdered milk with a certified content in PCB-52, PCB-101, PCB-118, PCB-156, and PCB-180. This material contains approximately 3.9% water and 25% fat. It is used after reconstituting and was supplied by the EC Community Bureau of Reference (BCR). 

In the above discussion, standard reference materials (SRMs) were mentioned often. A reference material (RM) is a material or substance suitable for use in calibrating equipment or standardizing solutions. A certified reference material (CRM) that a vendor indicates, via a certificate, is an RM. A standard reference material (SRM) is one that is distributed and certified by a certifying body, such as NIST. The SRM is the material to which all calibration and standardization materials should be traceable. A standard material becomes one when it is compared to or prepared from another. Ultimately, it all rests on the SRM — meaning all standard materials are traceable to an SRM (see Figure 5.10). 

Four basic requirements for accurate and precise determination of the amount of fluoride or total fluorine in any type of the sample are (1) the sample has to be appropriately pre-treated so that the required form of fluorine can be determined (2) interfering reactions have to be effectively suppressed (3) the final concentration of fluorine must be above the detection limit of the method and (4) if possible, method should be validated using certified reference material (CRM), or the results of analyses compared to the results obtained by an independent method. 

In order to make reliable comparisons it is therefore suggested that, in future studies, decomposition methods that are known to release all the fluoride should be used. Use of certified reference materials (CRM) as part of the quality assurance system should be mandatory. In addition, sufficient information to enable proper comparison of data from different studies must be provided. 

Segura, M., Camara, G, Madrid, G, Rebollo, C., Azcarate, J., Kramer, G. N., Gawlik, . M., Lamberty, A., and Quevauviller, Ph. (2004), Certified reference materials (CRMs) for quality control of trace-element determinations in wastewaters, Trends Anal. Chem., 23,194-202. 

Standard reference material (SRM) for wavelength accuracy, stray light, resolution check, and photometric accuracy can be purchased from NIST. Certified reference materials (CRMs) which are traceable to NIST and recertification services can be purchased from instrument manufacturers and commercial vendors [12]. The cost of neutral-density filters and prefabricated standard solutions in sealed cuvettes can be substantial. When purchasing performance verification standards from a secondary supplier other than a national standard organizations such as NIST in the United States and National Physical Laboratory (NPL) in the United Kingdom, make sure that the traceability of the standards are available in the certificates. The traceability establishes the relationship of individual results to the national standard through an unbroken chain of comparisons. 

Certified reference materials (CRMs) are mainly applied to validate the analytical procedure developed for routine analysis in order to determine the accuracy of analytical data, the recovery for selected elements, the uncertainty of trace element determination and the detection limits. Otherwise, in solid-state mass spectrometric techniques, such as SSMS, LA-ICP-MS, GDMS, SNMS or SIMS, one point calibration using CRMs has been established as an important calibration strategy to obtain reliable analytical data. The one point calibration is performed using the experimentally determined relative sensitivity coefficients (RSCs) on a suitable CRM with a similar trace/matrix composition. An RSC of a chemical element is defined as the ratio of the measured element concentration (experimentally determined) divided by the certified element concentration (accepted or recommended value of element concentration) in a given matrix. 

Solid certified reference materials (CRMs) are used for calibrating the analytical procedures in inorganic mass spectrometry. Quantification of analytical data in solid mass spectrometry via... 

To an increasing extent, the isotope dilution technique is being applied in the certification of standard reference materials, e.g., for Hg determination in a polyethylene certified reference material (CRM 680 and 681), or Cd and T1 determination in high purity Zn (CRM 325/2R), where ID-ICP-MS yields the most accurate data.45... 

---