Voltammetric behaviour of gallium(III) in the mineral-organic electrolytes with high solvating ability containinig dimethylformamide and limethylsulfoxide

The electroreduction of Ga(III) in aqueous media is related with a number of difficulties cause of its rather negative potential and hydrolysis addiction. Non-aqueous and mineral-organic media concerning analytical aspects of gallium chemistry are not accounted practically. Only the investigations on electroreduction of gallium and its alloys on copper from glycerine and ethylene glucol as well as its anodic behavior on DME in dimethylformamide medium might be mentioned. Aside from benzol-acetic solution was recommended for amperometric titration of Ga(III) by EDTA using back-titration of EDTA excess amount with the help of Bi(III)-solution. The determination of Ga(III) is also possible in the form of its acetylacetonate using aqueous-cloroform nitrate background electrolyte. The method of voltammetric determination of Ga(III) using monoethanolamine and tetraethylammonium bromide background electrolyte with previous Ga(III) extraction by tributylphosphate injected into carbon paste electrode has been described too. All methods mentioned above are sufficiently complicated and not allow to realize the condition of direct determination of gallium without accompanying elements separation. The perspective of application in voltammetry of p-elements the mineral-organic backgrounds electrolytes, containing organic solvents with high solvating ability has been shown earlier [5]. The peculiarities of voltammetric behaviour of Ga(III) in mineral-organic background electrolytes with high solvating ability, containing dimethylformamide (DMF), dimethylsulfoxide (DMS) and perchloric acid has been studied now. It has been shown that electroreduction of Ga(III) proceeds irreversible with 3 electrons participation at diffusion control of limiting current throughout the investigated concentration range of the background electrolyte components. The values of the Ga(III) diffusion coefficients in DMF- and DMS solutions has been found and the range of linear dependence of Ga(III) limiting diffusion current vs. its concentration in the solution has been stated. The influence of several accompanying elements upon the voltammetric behavior of Ga(III) in the studied conditions has been analyzed. Thus in perchloric dimethylformamide- and dimethylsulfoxide-containing solutions Ga(III) reducts on DME forming clear limiting current peaks which can be used for selective electroanalytical determination of Ga(III) in mineral-organic solvent in the wide range of its concentrations.