IAEA CRMs

Shuzhong, Z., Shaoxian, L. and Zhenhong, X, Rapid Determination of Sr by TBP Extraction. IAEA CRM, Vienna, 1991. 

Vajda, N., Ghods-Esphahani, A. and Danesi, P.R., Determination of radiostrontium in soil samples using a crown ether. IAEA CRM, Vienna, 1991. 

Vapirev, F.I. and Hristova, A.V., Rapid correlation assessment of Sr in fallout by gamma-spectroscopy. IAEA CRM, Vienna, 1991. 

From the mid 1980 s the rise of Quahty Standards, Total Quahty Management and Accreditation schemes created a booming demand for RMs and CRMs. Thus, the use and production of matrix RMs rapidly increased the new IAEA database lists 56 producers from 22 cormtries and about 1640 RMs. The 1998 Comar database, which covers a much wider scope, hsts more than 200 producers and around 10 000 RMs see Chapter 8 for more details. 

The minimum sample sizes currently recommended by CRM producers are generally =ioo mg (IAEA-TECDOC-825/880 1995/1996). These minimum sample sizes were developed for determinations made primarily on dissolved samples. There are, however, some CRMs available that may permit the successful use of much smaller sample aliquots as discussed in the examples below. 

IAEA efforts related to both CRMs and others, such as hair for total mercury and methyl mercury (prepared in India), and lichen for multi-element certification (prepared in Portugal) to assist biomonitoring programs in Brazil, Chile, China, Czech Republic, India, Italy, Malaysia, Slovenia, and Vietnam,... 

Interlaboratory exercises have to be a part of the measurement program in order to ensure, as far as possible, a consistent data set. CRMs of artificial precipitation samples and solid samples are available from various organizations, for example, BCR, NIST, and IAEA. In addition, laboratory intercomparisons are arranged annually by, for example, WMO/GAW and EMEP. Artificial precipitation samples are distributed to different laboratories. EMEP laboratory comparisons of the main components in precipitation have been conducted for 25 years, and they have provided important documentary evidence for the evolution of data quality in EMEP during this period. The results show that laboratory performance has improved during this period, so that at present most laboratories manage to be within the 10% relative standard deviation (RSD) for all the major ions (Table 17.4). 

The accuracy of the methods described above for the analysis of biological and food samples has been checked by dilferent approaches. These include recovery test and standard addition, use of independent analytical methods of proven validity, and verification of the method by means of CRMs, the latter two approaches being the most applied. In the specibc case of biological and food samples, a great variety of CRMs, such as those produced by NIST, BCR, NRC, and IAEA, are available. The reliability of the techniques mentioned in this survey has been mainly checked against these CRMs. There is much evidence in the literature that the capabilities of the solubilization sampling technique compare favorably with those of other techniques. 

Jayasekera and Freitas were the first to investigate the content of 24 chemical elements in rice grain and flour from Sri Lanka [19]. The purpose of their study was to compare the data obtained with the maximum permissible levels prescribed by international guidelines. Determinations were made by means of INAA with k0 standardization. The rice samples were collected from local markets and were representative of two major varieties, raw polished and parboiled rice. Prior to analysis, samples were freeze-dried and ground to fine powder. The CRM IAEA V-8 rye flour was used to check the accuracy of experimental... 

The leading CRM producers in the world are NIST, the National Research Council of Canada (NRCC), and the International Atomic Energy Agency (IAEA). Information about CRMs produced by NIST can be found at the NIST website, www.nist.gov/srm/index.cfm... 

IAEA currently specializes in the production of certified RM for radioactive isotope content, but also offers CRM for inorganic trace analysis, organic analysis, and determination of stable isotopes. Information can be foimd via the IAEA homepage, www.iaea.org, or directly from nucleus.iaea.org/rpst/Reference Products/ReferenceMaterials/index.htm... 

Pond sediment NIES 2 Lake sediment SL-1 River sediment CRM 320 Soil-5 IAEA Soil-7 IAEA " ... 

The ISO Council on Reference Materials (REMCO) has identified more than 170 RM producers worldwide for the various fields of analyses. Two main bodies - the National Institute of Standards and Technology (NIST, USA) and the Institute for Reference Materials and Measurements (IRMM, European Commission, Belgium), successor of BCR (which is now a trade mark for materials produced by IRMM) - cover several fields and ensure long-term availability of the CRMs due to the large batches of materials produced. Other producers specialize in a particular field of interest, e.g., the National Research Council of Canada (NRCC, Canada), the National Institute for Environmental Studies (NIES, Japan), the IAEA Marine Environment Laboratory (Monaco), etc., specialize in marine analysis. The International Atomic Energy Agency (IAEA, Austria) mainly provides materials for nuclear measurements but also supplies RMs for non-nuclear analyses. 

Certified reference materials (CRMs), described in the Appendix such as those available from NIST (http //ts.nist.gov/), IAEA (http //www.iaea.org), BCR (http //www.irmm.jrc.be), or other national or international standards bodies, are occasionally used as multielement calibration standards. The chief drawbacks of these materials are the difficulty of selecting an appropriate material for all the elements of interest and the inferior accuracy of certified element content compared with in-house preparations. The most important use of CRMs is to validate the results of a measurement if the certified value is obtained when a sample is analyzed in the same manner as the unknown, then the measurement is less likely to be in... 

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