Scientific publications

Content of sulfates in the Karelian's natural waters including atmospheric precipitations is enough low and there is the problem of determination it by different methods. The photometric method of determination sulfates was modified for the purpose of improves realization analyses and obtains reproducible results.
Photometric methods are widely applied in analytical practice by using derivatives of chromotropic acid. Very often such indicator is sulfonazo III or [3,6-bis (2-sulfophenylazo)-4,5-dihydroxy-2, 7-naphthalenedisulfonic acid tetrasodium salt].
All photometric methods by using sulfonazo III are based on sedimentation sulfates by barium ions and photometric determination free quantities of barium.
Experience testing analyses of sulfates at the laboratory of hydrochemistry and hydrogeology showed that basic defect of the method was low reproduction of graduated graphs. For elimination the defect was suggested to use a difference values optic densities: ΔD = D₆₄₀ – D₆₁₅. The new approach makes it possible to obtain reproducible graduated graphs to improve a convergence results with models of internal check and within the bounds of project ICP Waters.
The approach was applied for determination of sulfates in the samples collected from territory of Petrozavodsk in December 2008. In addition was calculated a percentage of anthropogenic sulfates by sulfates-chlorides ration in the sea aerosols.
Content of sulfates is low on the territory of Petrozavodsk except Solomennoe's sample. Percentage of anthropogenic sulfates is quite higher (91–98%) then percentage of natural sulfates (2–9%).