The direct determination of HgS by thermal desorption coupled with atomic absorption spectrometry

This research was aimed at the direct determination of HgS in environmental samples by means of thermal desorption coupled with atomic absorption spectrometry. Operating parameters of the apparatus used for thermal desorption (including a prototype desorption unit) are described in this work, as well as the procedure for measuring mercury release curves together with an evaluation of the analytical signal including two methods of peak integration. The results of thermal desorption were compared with HgS contents obtained by sequential extraction. The limits of quantification of the proposed method for the selective determination of the black and red forms of HgS were 4 μg kg− 1 and 5 μg kg− 1, respectively. The limit of quantification of red HgS in soils was 35 μg kg− 1. The developed analytical procedure was applied to soil and sediment samples from historical mining areas.