Use of Tow IAEA Intercomparison Studies to Assess the Appropriateness of Modern Analytical Methods

Abstract

Intercomparison studies provide a useful approach to characterise candidate reference materials and provide a tool to assess the performance of laboratories, instrumentation and sample work-up protocols. The IAEA organises intercomparison exercises for trace elements in a range of matrices which attract the participation of a large number of laboratories from around the globe. Participants are free to choose their own analytical strategy and therefore a wide range of digestion procedures and analytical methods are represented. A statistical assessment of the data obtained by up to 158 laboratories for six elements (Al, Fe, Se, Cd, Hg and Pb) representing ‘easy’, ‘problematic’ and ‘challenging’ analytes during two IAEA intercomparison studies on biological matrices, NIST SRM 1570a Spinach and a candidate reference material, IAEA-359 Cabbage, is discussed. The elemental concentrations for the elements studied range from the ng g ^-1 to the fraction of a percent level.