title: A mercury-free electrochemical sensor for the determination of thallium(I) based on the rotating-disc bismuth film electrode.
abstract: A bismuth film electrode was tested and proposed as an environmentally friendly sensor for the determination of trace levels of Tl(I) in non-deoxygenated solutions. Determination of thallium was made by anodic stripping voltammetry at a rotating-disc bismuth film electrode plated in situ, using acetate buffer as the supporting electrolyte. The stripping step was carried out by a square wave potential-time excitation signal. A univariate optimisation study was performed with several experimental parameters as variables. Under the selected optimised conditions, a linear calibration plot was obtained in the submicromolar concentration range, allowing the electrochemical determination of thallium in trace amounts; the calculated detection limit was 10.8nM and the relative standard deviation for 15 measurements of 0.1muM Tl(I) was +/-0.2%, for a 120s accumulation time. Interference of other metals on the response of Tl(I) was investigated. Application to real environmental samples was tested. The bismuth film electrode appears to be a promising tool for electroanalytical purposes, ensuring the use of clean methodology.
authors.affiliation: Departamento de Química e Bioquímica, Centro de Ciências Moleculares e Materiais, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisboa, Portugal.
authors.forename: E O
authors.initials: EO
authors.lastname: Jorge
authors.forename: M M M
authors.initials: MM
authors.lastname: Neto
authors.forename: M M
authors.initials: MM
authors.lastname: Rocha