Organomineral material for preconcentration and electrothermal atomic absorption spectrometry determination of Hg(II), Sn(II) in high-salinity natural and drinking waters with slurry sampling

The synthesis of new functionalized silica gel with immobilized thiosemicarbazone fragments by the reaction of aldehyde silica gels with thiosemicarbazide in an ethanol medium in the presence of a catalytic amount of hydrochloric acid is described. The material was characterized by thermogravimetric analysis and infrared spectroscopy data. Effective solid-phase extraction of Sn(II) and Hg(II) using synthesis organomineral material—silica with immobilized thiosemicarbazone fragment has been demonstrated. Determination of Sn(II) and Hg(II) in samples whose matrix excludes the possibility of direct ETAAS (electrothermal atomic absorption spectrometry) determination, for example in sea waters, an approach has been proposed to replace the matrix of the analyzed sample with a sorbent matrix based on modified silica. ETAAS conditions for the determination and preconcentration of Sn(II) and Hg(II) in the sorbent used with slurry sampling have been described. The proposed methodology for determination Sn(II) and Hg(II) was tested on the example of sea water of the Black Sea, fresh tap water and mineral drinking water “Esentuki.” The error of determination was no more than 10% rel. The detection limit for mercury was 50 ng/L, tin 7 ng/L. The concentration factor is 100 for both elements. The advantage of the developed ETAAS approach for the determination of mercury and tin in comparison with other spectroscopic methods (ICP-AES, ICP-MS) is shown.

Graphical abstract