Collect. Czech. Chem. Commun. 1993, 58, 2039-2046

Voltammetric and Potentiometric Determination of Gold in Gold-Plated Electrotechnical Components

Karel Vytřas, Ivan Švancara, František Renger, Malis Srey, Radmila Vaňková and Marie Hvízdalová

Department of Analytical Chemistry, University of Chemical Technology, 532 10 Pardubice, Czech Republic


Differential pulse voltammetry was used to determine gold in gold-plated electrotechnical components. Samples were dissolved to form tetrachlorourate, which was determined on a carbon paste electrode containing tricresyl phosphate as pasting liquid. A characteristic cathodic peak for tetrachlorourate, whose selective accumulation is based on extraction, is obtained during cathodic scan from +0.8 to -0.5 V vs Ag/AgCl electrode. The accompanying Fe(III) and Cu(II) ions from the matrix are masked by adding EDTA. Gold can be determined in the presence of their thousand-fold excess in the concentration range 1 . 10-5 - 1 . 10-7 mol l-1. The results were confirmed by potentiometric titration with a solution of 1-(ethoxycarbonyl)pentadecyltrimethylammonium bromide (Septonex) by using a coated-wire indicator electrode with a softened plastic membrane.