Instrumental neutron activation analysis (INAA) has been employed in the investigation of mass balance for mercury species
analysis in the analytical process. A new human hair reference material (IAEA-085) was analyzed for methylmercury using a
solid/liquid extraction procedure, with samples of extracts, residues, and untreated samples being analyzed by INAA. The certified
reference material NIES CRM No. 13, human hair, was analyzed in parallel. From the results obtained through the mass balance
studies, it was found that the extraction procedure was quantitatively complete, and that there was no difference between
the mass balance of Hg and the total Hg in the untreated materials.