Reference materials metrology

The analysis was performed by SRXRF at the XRF beam-line of VEPP-3, Institute of Nuclear Physics, Novosibirsk, Russia. For accuracy control the International Certified Reference Materials were used. There were obtained all metrological characteristics, namely precision, accuracy and lower limits of detections. 

We will also review the development of chemical metrology in the pharmaceutical industry, an industry that is ever more closely related to molecular biology. The pharmacists first developed quality protocols and reference materials more than 40 years ago, quite independently of the activities of ISO and the REMCO Technical Committee. Only in the closing years of the 20th Century have these two important groups begun to realize that they share common objectives. 

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. 

Chase GW and Long AR (1997) Nutritional Metrology, PART 4, The Role of a Zero Control Reference Material. Food Testing and Analysis, Jun/Jul 1997, 3 30-33. 

Tanner JT, Wolf WR, and Horwitz W (1995) Nutritional Metrology. The role of reference materials in improving quality of analytical measurements and data on food components. In Greenfield H, ed. Quality and Accessibility of Food-Related Data, pp 99-104. AOAC International, Gaithersburg MD. 

Wolf WR and Iyengar V (1996) Nutritional metrology Food-based reference materials. Food Testing Analysis 2(6) 27-3i. 

Section 5.2 introduced the subject of metrological traceability and calibration and the use of pure chemical substances and reference materials in achieving trace-ability. Reference materials are used as transfer standards. Transfer standards are used when it is not possible to have access to national or international standards or primary methods. Transfer standards carry measurement values and can be... 

A reference material characterized by a metrologically valid procedure for one or more specified properties, accompanied by a certificate that states the value of the specified property, its associated uncertainty and a statement of metrological traceability. 

Metrologically valid procedures for the production and certification of reference materials are given in, among others, ISO Guide 34 [7] and ISO Guide 35 [5]. 

Laboratories must use calibration standards that are metrological trace-ability to an embodiment of the unit in which they are expressed. This requires use of certified reference materials, usually to make up working standards that calibrate instruments in the laboratory. Implicit is that results will be expressed in common units, and while this is increasingly the case, the example of the Mars Climate Orbiter (chapter 1) should signal those still using versions of imperial units that it might be time to join the rest of the world and use SI units. 

There are some existing texts that cover the material in this book, but I have tried to take a holistic view of quality assurance at a level that interested and competent laboratory scientists might learn from. I am continually surprised that methods to achieve quality, whether they consist of calculating a measurement uncertainty, documenting metrological traceability, or the proper use of a certified reference material, are still the subject of intense academic debate. As such, this book runs the risk of being quickly out of date. To avoid this, I have flagged areas that are in a state of flux, and I believe the principles behind the material presented in this book will stand the test of time. 

Key words Traceability Mole Definition Measurements Chemical metrology Calibration Validation Reference materials... 

At the metrological top, the CGPM defines SI units, and its executive, the CIPM, oversees their dissemination [12], The rather newly established CCQM organizes Key Comparisons of measurements on reference materials among the national metrology institutes to ensure adequate measurement capabilities at the highest metrological level. Several of these materials are relevant to calibration hierarchies in laboratory medicine. 

It is, therefore, praiseworthy that internationally organized cooperation and collaboration within an agreed system is emerging from European and global consultations since 1999, not least prompted by the EU Directive on IVD MD s essential requirement of metrological traceability for values assigned to reference materials, which will become a challenge to industry. 

Adviser on Metrology in Chemistry to the Director of the Institute for Reference Materials and Measurements, European Commission - JRC, 2440 Geel, Belgium... 

Key words Traceability chain Metrology in chemistry Reference material Amount standard Validation... 

The Slovak Institute of Metrology (SMU) has recently rebuilt its high-precision coulometric equipment to be used as a national standard for amount of substance measurements. Its main purpose is certification of primary reference materials of composition with directly determined main component. These primary reference materials can be subsequently used for disseminating traceability into different chemical measurements. 

Historically, there have been several ways of demonstrating metrological linkages of traceability. One of the earliest was for a reference laboratory to calibrate an artifact by measuring it and then provide it, along with certified results, to one or more laboratories so that they could also measure it and then compare their results with those of the reference laboratory. Later, distribution of certified reference materials, produced in lots by reference laboratories, provided an exactly analogous linkage for those kinds of materials amenable to production and certification in lots. 

De BiLvre I Kaarls R, Rasberry S, Reed W (1995) Metrology and the role of reference materials in validation and calibration for traceability of chemical measurements. Proceedings of the 1995 NCSL Workshop and Symposium, pp 479 494... 

National traceability or dissemination structures, internationally linked via comparison measurements under the CIPM Mutual Recognition Arrangement, are beginning to play a central role in establishing trace-ability of chemical measurements in practice. Reference materials are the most important transfer standards for disseminating traceability (more precisely the units of measurement) to the user level. Availability of certified reference materials with evidence of their metrological quality is, however, very limited. Great efforts are necessary to improve this situation. 

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