Validation of a Horizontal Standard: of Elements in Aqua Regia and Nitric Acid Digests by GF-AAS in a European Intercomparison Exercise

Project HORIZONTAL is interdisciplinary aiming at a harmonisation and horizontal standardisation of test procedures, in particular for sludge, soils and biowastes. In the context of this standardization project, a series of draft technical specification were designed upon an extensive desk study, fine-tuned after expert consultations and finally validated in international intercomparisons exercise. This report summarises the work performed within the validation study of the draft standard for the determination of elements in aqua regia and nitric acid digests by graphite furnace atomic absorption spectrometry method (GF-AAS). It further explains the underlying statistical concept for the calculation of reproducibility and repeatability from intercomparisons data. In addition all single values, results of the statistical evaluation as well as background information on the validation materials used are described and explained.