[en] Methods for the preparation of hair samples and soft tissue samples employed in instrumental neutron activation analysis and in electron probe microanalysis are given. Realistic values of detection limits for liver, muscle, hair and nail samples are found for different irradiation and counting conditions in both techniques. The variation of flux in the reactor core affects the intensity of the activity produced in the sample, so method and results of measurement of these variations were investigated and are presented. Hair and nail samples collected from a selected population group in Africa were analysed using the above described techniques, as were hair samples collected from breast cancer patients and both sets of results are given. The distribution of some elements along selected lines on the hair cross section were studied using the electron probe microanalyser, whereas the elemental content of microvolumes in both pigmented and matrix areas in the hair cross section were looked at using the transmission electron microscope with electron probe microanalyser. Cancerous and non-cancerous breast tissues were analysed for their elemental content. (author)