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Analytical procedures are described for the solid state phase microanalysis of synthetic and natural tin-, arsenic-, and antimony-bearing sulfosalts and sulfides of thallium, tin, lead, and silver. In these procedures, abrasive stripping voltammetry and coulometry of the solid phases are applied. Trace amounts of the sample compounds were transferred onto the surface of a graphite electrode and the electrochemical reduction or oxidation was followed by voltammetric techniques. The most valuable technique for distinguishing different mineral phases is to record the anodic dissolution voltammograms after a preliminary electrolytic reduction of the sulfides or sulfosalts to the elementary metals which are still confined to the electrode surface. For various compounds an approach was developed in which the ratio of charges consumed during reduction and oxidation of the solid phases is used for unambiguous identification. Coulometric measurements are also used for the determination of the quantitative composition of the solid phases.

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Phase identifications and quantitative analyses of mixed crystals by means of abrasive stripping voltammetry are reported using covelliteklockmannite (CuS(x)Se(1-x)) and emplectite-chalcostibite (CuBi(x) Sb(1-x)S(2)) mixed crystals as examples. The composition of CuS(x)Se(1-x) can be determined within a span of x=+/-0.03. Additionally the standard potential of the Cu/CuSe-electrode is measured to be E(. )(Cu/CuSe)= -0.749 V vs. Ag/AgCl.