Hulled sesame seeds possessing relatively low selenium content were investigated for Se-speciation in order to assess the possible role of sesame seeds in Se-supplementation. As sesame seed is widely used by sprinkling over bakery products in Hungary, this study also deals with the effect of a simulated bakery process on selenium species distribution. Since fatty seeds, like sesame tend to become rancid in consequence of no appropriate or long storage time, the prospect of conversion of selenium species was under investigation. The sample was analysed for total selenium and selenium speciation by the means of a coupled technique, HPLC-UV-HG-AFS. Peculiar attention was paid to avoid the misidentification of selenium species when co-elution problems may occur by applying independent HPLC separation techniques (cation and anion-exchange chromatographies). For validating the total Se measurements, a certified reference material (BCR-422) was used. Different sample preparation techniques were applied to reach the maximal extraction efficiency. An adequate extraction efficiency (83%) was achieved, making the quantification of selenomethionine (552 +/- 14 mu g SeMet as Se kg(-1) in the original sesame) possible. Neither the simulated bakery process (roasting) nor forced oxidation caused any changes in the Se-species distribution of sesame seeds. (c) 2006 Elsevier Ltd. All rights reserved.