Authors:M. Gouveia, J. Seabra e Barros, M. Tavares and M. Freitas
Instrumental neutron activation, atomic absorption spectroscopy and conventional methods of analysis were used on eight different silicate rocks and two minerals. Trace elements and major constituents were determined. It was considered that the methods should be regarded as complementary analytical techniques.
Authors:M. Carmo Freitas, L. Moens, P. De Paepe and J. Seabra E Barros
A 7 kg stone of a Carrara marble was reduced to grains smaller than 100 m, mixed and homogeneized in order to prepare a marble reference material. The homogeneity was tested for 16 elements by instrumental neutron activation analysis (INAA). Through a one-way analysis of variance based on several analyses of each of 15 bottles and within the same bottle, it was concluded that the inter-bottle heterogeneity is not greater than the intra-bottle heterogeneity. Results on the concentration of major and trace elements in the marble reference material, obtained by different laboratories and different techniques, are given. The limestone certified reference material KALKSTEIN KH was used to evaluate measurement accuracy, to intercalibrate laboratories, and to provide compatibility of measurement data.