Results of proficiency testing with regard to sediment analysis by FAAS, ICP­MS and TXRF

Three different techniques of instrumental analysis applied at ISAS were evaluated within a proficiency test, organised by IRMM in Geel. The 3 techniques, in particular flame atomic absorption spectrometry (FAAS), inductively coupled plasma mass spectrometry (ICP­MS) and total­reflection X­ray fluorescence (TXRF) were used for multielement trace analysis of a sediment sample after digestion. The reported results of up to 9 elements were evaluated with respect to the reference values after the disclosure of the latter. The relative deviations, mostly <4%, demonstrate the high accuracy of the 3 techniques. In addition, the uncertainty bars of report and reference show a high degree of overlapping, which gives evidence that the mean values are not significantly different. The high ranking of ISAS results among all 239 participants of the test confirms these findings. With regard to accuracy, ICP­MS and TXRF are somewhat inferior to conventional FAAS but in their favour they are labour­ and time­saving and have a good detection power.