Development of analytical procedures based on abrasive stripping coulometry and voltammetry for solid state phase microanalysis of natural and synthetic tin‐, arsenic‐, and antimony‐bearing sulfosalts and sulfides of thallium, tin, lead, and silver

Abstract

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.

Electroanalytical chemistry for the analysis of solids: Characterization and classification (IUPAC Technical Report)

“…The relative quantification of constituents (the molar and/or mass ratio of different electroactive components) of solids by SSEAC is possible applying different chronocoulometric and voltammetric approaches. An example is the determination of the ratio of thallium to tin in various thallium-tin sulfides [174]. The transferred sulfide is reduced using an electrolyte solution that contains mercury ions.…”

“…Similar to what happens in case of thin-mercury film electrodes, the deposited mercury dissolves the tin and the thallium, and the oxidation of the two metals can be recorded by chronocoulometry so that the ratio can be calculated. Another example is the determination of the oxidation state of sulfur in different thallium sulfides [174]: That method is based on measuring in a first step the charge consumed for reduction of the thallium sulfide to thallium, and in a following step the determination of the charge of oxidation of the thallium metal. The metal ratios of high-temperature superconductors have also been determined by SSEAC [175].…”

Electrochemical Detection of High Oxidation States of Chromium(IV and V) in Chromium‐Doped Cassiterite and Tin‐Sphene Ceramic Pigmenting Systems

“…[16] Recently, Scholz et al described the electrochemistry of natural and synthetic tin sulfosalts using the voltammetry of microparticles methodology. [17] This scheme has previously been applied for studying the electrochemistry of SnO 2 and Sn-rich glazed ceramics. [18] Studies on nanosized SnO 2 particles dispersed on graphite electrodes, [19] nanocrystalline tin oxide electrodes [20] and modification of the film of SnO 2 nanocrystallites with organic reagents, [21] all devoted to the detection of selected analytes, have also been reported.…”

Voltammetry as an Alternative Tool for Trace Metal Detection in Peloid Marine Sediments

“…This solid state electroanalytical technique is based on the mechanical transfer of microparticles of solid compounds to an electrode surface, which is then used as the working electrode in the classical voltammetric experiment [4 -5]. The adjective abrasive refers to the method of transfer of the solid depolarizer onto the electrode surface, and the adjective stripping refers to the fact hat the solid is usually stripped of the electrode surface during the measurement [4]. Sometimes it is possible to reduce a solid sample on the electrode surface before the measurement commences.…”