The degree of homogeneity is normally assessed by the variability of the results of independent analyses of several (e.g.,
15) normal-scale replicates. Large sample instrumental neutron activation analysis (LS-INAA) with a collimated Ge detector
allows inspecting the degree of homogeneity of the initial batch material, using a kilogram-size sample. The test is based
on the spatial distributions of induced radioactivity. Such test was applied to samples of Brazilian whole (green) coffee
beans (Coffea arabica and Coffea canephora) of approximately 1 kg in the frame of development of a coffee reference material. Results indicated that the material do
not contain significant element composition inhomogeneities between batches of approximately 30–50 g, masses typically forming
the starting base of a reference material.