Lead sampling procedures final evaluation

Procedure blanks are performed at each occasion of measurement and their results are discussed before correction can be applied. Finally, all results are corrected for the water content in the sample. Particular attention is given to the reliability of the signal of the detector and the calibration of this signal. For detectors with a poor linear dynamic range the calibration must be performed in an adequate concentration so that extrapolation is possible to the signal of the unknown sample. Finally, all chromatograms — samples with and without internal standard(s), blanks, calibration solutions — are examined by all participants collectively. Any remaining unresolved question or any doubt on one or the other step in a procedure that may affect the trueness of the result leads to rejection of the data. The methods and data that successfully passed this technical evaluation are used to calculate the certified value and its uncertainty. 

Interlaboratory exercises focusing on nuclear forensics have been initiated by the Joint Research Centre (JRC) of the European Community. The two most recent exercises were called NUSIMEP-6 (Aregbe et al. 2008) and NUSIMEP-7 (Truyens et al. 2013) (NUSIMEP—Nuclear Signatures Inter-laboratory Measurement Evaluation Programme). In these exercises, identical samples were sent to the participating laboratories and the predefined analytes (content and isotopic ratios) were measured and reported to the coordinators, who then compiled the results, compared them with the target value, and produced a report. The remainder of the samples that were not consumed in the measurements can subsequently serve as standards for future measurements. One other benefit of these intercomparisons is that the accuracy and effectiveness of the different analytical procedures and the instrumentation can be assessed. In addition, corrective measures can be implemented in order to improve the performance. Finally, the cooperation between the scientists and the laboratories can lead to the development of standard procedures and recommended methods. This is essential for nuclear forensics where the implications of the analytical results, as mentioned earlier, may evoke political and even military actions in some cases. 

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