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This Bulletin describes the simultaneous determination of gold and copper by potentiometric titration using an Fe(II) solution as titrant. Fe(II) reduces Au(III) directly to the free metal, whereas Cu(II) does not react. By the addition of fluoride ions the Fe(III) is complexed and a shift of the redox potential is effected. Afterwards, potassium iodide is added, thus reducing the Cu(II) to Cu(I), and the free iodine is again titrated with the Fe(II) solution using a Pt Titrode.Chemical reactions:Au(III) + 3 Fe(II) → Au + 3 Fe(III)2 Cu(II) + 2 I- → 2 Cu(I) + I2I2 + 2 Fe(II) → 2 I- + 2 Fe(III)

In the following tables, the half-wave potentials or peak potentials of 90 metal ions are listed. The half-wave potentials (listed in volts) are measured at the dropping mercury electrode (DME) at 25 °C unless indicated otherwise.

Silver is an important metal not only in jewelry and silverware but also in electrical conductors and contacts. The knowledge of the exact silver content in fine silver and silver alloys ensures that quality standards for jewelry and silverware are met. As for the plating industry, the knowledge of the amount of silver in silver plating baths helps to run the bath efficiently.While X-ray fluorescence (XRF) is a fast alternative to determine the silver content in fine silver and silver alloys, it can only determine the silver content of the outermost sections of the metal. In contrast, titration offers a more comprehensive solution considering the whole sample, thus preventing fraud by thick plating.This application bulletin describes the potentiometric determination of silver in fine silver and silver alloys accordingto EN ISO 11427, ISO 13756, GB/T 17823, and GB/T 18996 as well as in silver plating baths by a titration with potassium bromide or potassium chloride, respectively

Halides interfere with most determinations of mercury or silver. However, if mercury or silver is titrated with sulfide ions, extremely insoluble sulfides are formed.A simple method is described that allows the direct titration of mercury(II) or silver(I) compounds in the presence of halides. The potentiometric titration takes place under alkaline conditions using thioacetamide as the titrant after formation of the EDTA complex.Organic compounds that are insoluble in alkaline EDTA can also be titrated after a Schoeniger digestion.

This document outlines complexometric and potentiometric determination of metal ions via EDTA titration using a copper-selective electrode (Cu-ISE) with a durable epoxy shaft and crystal membrane. Because the electrode is insensitive to complexing agents, a preformed Cu–metal complex must be introduced into the sample prior to analysis. The method, applicable to direct or back-titration, exploits EDTA–metal formation constants to define equivalence points and enables quantification in several different matrices.

This Application Bulletin describes the stripping analysis of Ag at the rotating disk electrode (RDE) with glassy carbon tip (GC) or Ultra Trace graphite tip. In routine operation, the determination limit lies at approx. 10 μg/L Ag, with careful work 5 μg/L Ag can be obtained. After appropriate digestion, silver determination is also possible with samples containing a relatively high proportion of organic substances (e.g. wine, foodstuffs etc.). The method has been developed primarily for water samples (well, ground and wastewater, desilvering solutions of the photographic industry).

This Application Bulletin describes …

The study of the electrochemical behavior of platinum in acidic media is of crucial importance in fundamental electrochemistry and electrocatalysis. Most electrocatalytic processes occurring at Pt electrodes are highly sensitive to the structure of the platinum surface. Cyclic voltammetry (CV) is a widely used rapid measurement technique that provides both a qualitative and quantitative fingerprint of platinum surfaces. A comparison of results given by linear and staircase CVs is presented in this Application Note.

Many different configurations are made possible when using two-, three-, or four-electrode cell setups in research. Depending on the experimental requirements, one setup may be preferred over another. Therefore, the proper electrode arrangements for these three situations are defined in this Application Note. As an example, the potential at the counter electrode is measured during the platinum oxidation in acidic media, with the second sense (S2) of VIONIC powered by INTELLO. Since dissolved Pt in solution could bias the results, it is important to be able to monitor the potential of the counter electrode.

In this Application Note, the electrochemical properties of electrodes with a micrometer-size surface area are compared with the electrochemical properties of electrodes with millimeter-size surface area. The comparison is made through cyclic voltammetry in a Fe3+/Fe2+ (ferro/ferri) solution, and the differences in the voltammograms are explained with the different diffusion profiles at the electrode-electrolyte interface.

Thermometric complexometric titration of metals is often performed with tetrasodium EDTA. This Application Note explains the standardization of tetrasodium EDTA titrant with copper.

Standardization of copper back-titrant using standard tetrasodium EDTA titrant in the determination of metals.

Silver and nitric acid are determined in silver electrolyte solutions by means of thermometric titration. The method provides accurate results in a short time and is ideally suited for routine process control.

Simultaneous determination of cyanide and silver in a silver plating bath by potentiometric titration with silver nitrate using the Ag-Titrode.

Determination of palladium(II) by potentiometric titration with hexadecylpyridinium chloride using the «Ionic Surfactant» electrode.

Palladium is determined at a pH value of 4 to 5 using back titration with zinc sulfate. Xylenol orange is used as the indicator for visualization of the endpoint. The equivalence point is determined with the Optrode at a wavelength of 610 nm.

The knowledge of the exact silver content of silver allows used for jewelry is very important to ensure the quality of jewelry. Therefore, the determination procedure is regulated internationally and nationally. A common approach is the titration with potassium bromide after an acidic digestion of the silver using a silver electrode for indication.

The concentration of Pd in pharmaceutical products is determined by polarography after wet digestion.

Rhodium and platinum can be determined in water samples after UV digestion and complexation by adsorptive stripping voltammetry (AdSV) at the HMDE.

For the determination of heavy metals in wine, UV digestion is required to mineralize the sample. The determination of platinum and rhodium is carried out with adsorptive stripping voltammetry (AdSV) at the HMDE.

Platinum in urine can be determined by adsorptive stripping voltammetry (AdSV) after UV digestion of the sample.

Gold can be determined by anodic stripping voltammetry (ASV) in the µg/l range at the Ultra Trace Graphite electrode. The solution should not contain halide ions.

The concentration of Pd in an activator bath is determined by polarography in ammonium chloride electrolyte.

Controlling Au(I) levels in gold plating baths is required for high quality. Voltammetric analysis with the Multi-Mode Electrode Pro is an efficient solution.