A Simple Procedure for Decomposition of Human Hair Using Polypropylene Vials for Selenium Determination by Hydride Generation Atomic Absorption Spectrometry

Two procedures for wet decomposition of human hair samples were compared for selenium determination by hydride generation atomic absorption spectrometry (HGAAS). These procedures involve treatment with HNO₃/H₂O₂ and H₂SO₄/HNO₃, respectively, using small disposable polypropylene (PP) vials. Analytical steps from weighing to dilution were performed in the same individual PP vial. After sample weighing (10±3mg) and reagent addition, decomposition was performed in a conventional oven (20h, 100°C). Addition of sulfamic acid prior to HGAAS measurements was necessary to minimize interference due to residual nitrogen oxides from the decomposition step. The accuracy was estimated using certified hair reference analysis which yielded an agreement higher than 97% (recovery tests). The absolute limit of detection was 1.2ng (3 s; n=10), corresponding to 0.12µgg^–1 in the dry sample.