Sequential Voltammetric Determination of Ultratrace Osmium, Ruthenium and Iridium. Application to Superficial Water

Abstract

The present work, regarding the determination of ultratrace Os(VIII), Ru(III) and Ir(III) in superficial waters is an interesting example of the possibility to simultaneously, or better sequentially determine each single element in real samples by voltammetry. The method is based on the catalytic current of the Os(VIII)-and Ru(III)-bromate systems by square wave voltammetry and on the Ir(III) determination by square wave catalytic adsorptive stripping voltammetry. 0.5 mol L À1 acetate buffer pH 4.9 + 7.7 10 À2 mol L À1 NaBrO 3 and 0.5 mol L À1 acetate buffer pH 4.9 + 7.7 10 À2 mol L À1 NaBrO 3 + 2.3 10 À5 mol L À1 cetyltrimethylammonium bromide (CTAB) + 0.2 mol L À1 KCl were employed as the supporting electrolytes. The analytical procedure was verified by the analysis of the standard reference materials: Sea Water BCR-CRM 403 and Fresh Water NIST-SRM 1643d. For all the elements, the accuracy, expressed as relative error e (%), was satisfactory, being lower than 6 %, while precision as repeatability, expressed as relative standard deviation, s r (%), was generally lower than 5 %. Once set up on the standard reference materials, the analytical procedure was transferred and applied to superficial water sampled in proximity to superhighway and in the Po river mouth area.

Experimental determination of concentration factors of Ni, Ru and Sb in the phytoplankton species Phaeodactylum Tricornutum

“…Data on ruthenium and antimony concentrations in Kattegat or the Baltic Sea could not be found. The ruthenium concentration in heavily tra cked waters in the Mediterranean Sea has been measured to be 0.5 nM [21] which is much lower than our measured values. However, ruthenium pollution occurs to an important extent through wear of ruthenium containing alloys which are frequently used in high-wear applications [21], resulting in small ruthenium-containing particles which may have been included in our analysis.…”

“…The ruthenium concentration in heavily tra cked waters in the Mediterranean Sea has been measured to be 0.5 nM [21] which is much lower than our measured values. However, ruthenium pollution occurs to an important extent through wear of ruthenium containing alloys which are frequently used in high-wear applications [21], resulting in small ruthenium-containing particles which may have been included in our analysis. The antimony concentration in the Baltic Sea has been measured to be 0.3 -0.8 nM [22] and 1.7 nM in the North Atlantic [23] which is similar to our measured data.…”

Ruthenium redox equilibria: 1. Thermodynamic stability of Ru(III) and Ru(IV) hydroxides

“…The choice of the appropriate method requires knowledge of the forms of existence of ruthenium in solution and the composition of its complex compounds. Depending on the solution pH, metal ion concentrations in solution, presence of oxidants and reductants as well as their concentration, ruthenium can exist in the form of several complexes, each exhibiting its own catalytic and voltammetric activities [6,7]. Within research of the reduction -oxidation mechanism, it is necessary to know if some coexisting species are reduced simultaneously or, conversely, the process has a "stepwise" character and one species reduces gradually [8].…”

Iridium and lead as vehicle emission pollutants: Their sequential voltammetric determination in vegetable environmental bio-monitors

“…The present work is the continuation on the study relevant to the presence of PGMs in the environment [21][22][23]. It suggests a method for sequentially determining, by voltammetric technique, Ir(III) and Pb(II) in vegetable environmental matrices.…”