Ti metal electrode as an unconventional amperometric sensor for determination of Au(III) species

Abstract

The control of the noble metal concentration is crucial in order to increase the efficiency of hydrometallurgic processes in mining and in the recovery of precious materials from electronic waste. The present study is devoted to the development of an effective procedure for the quantification of Au(III) species dissolved in aqueous solutions, similar real complex matrices included. In particular, a novel electrode system based on Ti has been studied. This electrode material is still poorly investigated in the framework of electroanalysis, despite its lack of sensitivity to common interfering species, such as oxygen; hence, the determination of metal species can be carried out without performing deaeration of the solution. In addition, the interfering effect due to the presence of other heavy metal ions, such as Ag, Fe and Pb, has been minimised by a proper choice of the conditions adopted for the amperometric measurements. Ti electrodes exhibit reproducible electrochemical responses, even in the presence of high concentration of organic fouling species typical of biosorption processes.

Nanostructured Au/Ti bimetallic electrodes in selective anodic oxidation of carbohydrates

“…Interestingly, the removal of oxygen through deaeration, by bubbling nitrogen through the solution for 30 min, does not lead to significant variation of the electrochemical responses. In fact, the influence of the oxygen, is not relevant for the reactions on Ti electrode surface [2] at variance with many other electrodes used in electrochemistry.…”

“…The deposition has been performed at constant potential (+0.10 V) for 30 s in a 1 Â10 À3 M Au(III) solution, prepared by dilution of a 1000 ppm stock solution of AuCl 4 À (CPI International Peak Performance TM Standards, USA) in 0.1 M HClO 4 [2]. Before the deposition the Ti electrodes were polished using 1200, 2500 and 4000 emery paper and 6, 3, 1 mm diamond spray (Arfex microcrystalline diamond spray from Remet) until mirror-like surfaces were obtained.…”

“…Ti constitutes a novel electrode material in the fields of electrocatalysis and electroanalysis [1,2]. In our previous papers we reported the electrochemical behaviour of bare Ti electrodes with respect to strong oxidizing species [1] and to heavy metals [2]: effective amperometric sensing systems for hydrogen peroxide, hypochlorite ions, and Au(III) species have been developed.…”

“…In our previous papers we reported the electrochemical behaviour of bare Ti electrodes with respect to strong oxidizing species [1] and to heavy metals [2]: effective amperometric sensing systems for hydrogen peroxide, hypochlorite ions, and Au(III) species have been developed. It is important to underline that a layer of Ti x O y , few nanometer thick, spontaneously forms on Ti surface [3].…”

A rapid and sensitive spectrofluorometric method for the determination of Au(III) based on fluorescence quenching of a 1,3,5-triphenyl-2-pyrazoline

“…* Correspondence: abasoglu@gumushane.edu.tr Due to the low concentration of gold ions in environmental samples and their great importance, many reports exist on the analysis of trace amounts of gold ions in water and several matrixes. Therefore, various analytical techniques such as spectrophotometry, 11 atomic absorption spectrometry (AAS), 12 thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS), 13 carbon slurry sampling graphite furnace atomic absorption spectrometry (GFAAS), 14 inductively coupled plasma atomic emission spectrometry (ICP-AES), 15 inductively coupled plasma mass spectrometry (ICP-MS), 16 and electrochemistry 17 have been reported for detecting the amount of gold ions. However, these methods are time-consuming, have interference problems, and require complicated and expensive instruments.…”