Proficiency testing Programme

Table 4 Interlaboratory comparison of enzyme activity measurements. Source Austrian Proficiency Testing Programme...

Traceability and its role in interlaboratory comparisons (proficiency testing programmes), modeled on trace element determination in biological materials... 

The ISO 17025 standard [3] describes monitoring the quality assurance of test and calibration results by, amongst other means, the regular use of CRMs and/or internal quality control using secondary reference materials and by participation in inter-laboratory comparisons or proficiency testing programmes. 

The issues of method validation and assessment of measurement uncertainty in the determination of potentially toxic trace elements in rice are of permanent interest for the scientific community. In this context, the sources of uncertainty associated with the determination of Cd, Cu, Pb, and Zn have been recently estimated in rice through an interlaboratory comparison [30]. Four Brazilian laboratories participated in the proficiency test. The analytical technique used were FAAS, ET-AAS, and ICP-AES. The rice samples were supplied by the Institute for Reference Materials and Measurements (IRMM), Joint Research Center of the European Commission, within the scope of the interlaboratory comparison International Measurement Evaluation Programme (IMEP) 19 Trace Elements in Rice (see also Chapter 7 in this book). Three out of the four laboratories reported values close to the reference values. It was emphasized that, in order to establish a reliable uncertainty budget, all significant sources of uncertainty should be identified. 

With reference to the measurement of artificial and natural radionuclides in environmental samples, activities of the Agency s laboratories in Seibersdorf include the preparation, characterisation, and distribution of reference materials of terrestrial origin, organisation of interlaboratory comparison exercises and proficiency tests, co-ordination of the activities of the ALMERA network, provision of training and expert assistance to scientists from Member States (MS) laboratories, and provision of analytical and radioanalytical support for the benefit of the programmes and projects of the IAEA and its Member States. 

Nowadays it is generally accepted that laboratory proficiency testing schemes are an important quality assurance tool in environmental monitoring programmes. Apart from using validated analytical methods and internal laboratory quality control procedures, the regular participation of laboratories in interlaboratory comparisons is required to ensure the accuracy and comparability of data. 

The current state of practice also varies considerably across sectors. Under the VAM programme, the aims are to increase user confidence in the validity of data derived from portable measuring equipment and to improve the reliability and comparability of measurements made using portable equipment. The possibility of establishing formal QA and QC procedures and proficiency testing for out-of-laboratory measurements will also be explored. 

We acknowledge financial support from the Sixth Framework Programme of the European Union (Contract SSPI-CT-2003-502492 http //www.swift-wfd.com). We also thank Nel Frijns and the RIZA monitoring team in Eijsden (The Netherlands), the local Environmental Agency (in the Aller) for permission to work. Finally, we thank all the partners in the SWIFT-WFD consortium who carried out reference measurements, prepared the reference materials, participated in the proficiency testing and in field studies. 

In the field of QA/QC the network will check regularly on the availability of methods for high-priority substances and their validation status, and initiate, whenever necessary, the organisation of interlaboratory studies for specific emerging substances. QA/QC information, such as available reference materials, proficiency testing schemes and training programmes for laboratories will be circulated. 

Participation in proficiency testing (PT) programmes is included as part of the requirements that the laboratories must fulfil in order to demonstrate their competences in analysing relevant physico-chemical or chemical measurands under the WED. 

Samples from international laboratory proficiency test exercises were also analysed, these included five soils from the Mixed Analyte Performance Evaluation Programme (MAPEP), USA Department of Energy, Idaho Falls, Idaho, (MaS21, 23, 24, 25 and 26) and one soil from the Institutde Radioprotection et de Sflrete Nucleaire (IRSN), Le Visenet, Cedex, France, (113SL300). 

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