title: Sensitive voltammetric determination of lead released from ceramic dishes by using of bismuth nanostructures anchored on biochar.
abstract: A simple and sensitive electroanalytical method was developed for determination of nanomolar levels of Pb(II) based on the voltammetric stripping response at a carbon paste electrode modified with biochar (a special charcoal) and bismuth nanostructures (nBi-BchCPE). The proposed methodology was based on spontaneous interactions between the highly functionalized biochar surface and Pb(II) ions followed by reduction of these ions into bismuth nanodots which promote an improvement on the stripping anodic current. The experimental procedure could be summarized in three steps: including an open circuit pre-concentration, reduction of accumulated lead ions at the electrode surface and stripping step under differential pulse voltammetric conditions (DPAdSV). SEM images revealed dimensions of bismuth nanodots ranging from 20 nm to 70 nm. The effects of main parameters related to biochar, bismuth and operational parameters were examined in detail. Under the optimal conditions, the proposed sensor has exhibited linear range from 5.0 to 1000 nmol L(-1) and detection limit of 1.41 nmol L(-1) for Pb(II). The optimized method was successfully applied for determination of Pb(II) released from overglaze-decorated ceramic dishes. Results obtained were compared with those given by inductively coupled plasma optical emission spectroscopy (ICP-OES) and they are in agreement at 99% of confidence level.
authors.affiliation: Laboratório de Sensores Eletroquímicos (LabSensE), Departamento de Química, Universidade Federal do Paraná (UFPR), CEP 81.531-980 Curitiba-PR, Brazil.
authors.forename: Deonir
authors.initials: D
authors.lastname: Agustini
authors.affiliation: Laboratório de Química de Húmus e Fertilizantes, Departamento de Química, Universidade Federal do Paraná (UFPR), CEP 81.531-980 Curitiba-PR, Brazil; Instituto Nacional de Ciência e Tecnologia de Energia e Ambiente (INCT/CNPq), Brazil.
authors.forename: Antonio Salvio
authors.initials: AS
authors.lastname: Mangrich
authors.affiliation: Laboratório de Sensores Eletroquímicos (LabSensE), Departamento de Química, Universidade Federal do Paraná (UFPR), CEP 81.531-980 Curitiba-PR, Brazil.
authors.forename: Márcio F
authors.initials: MF
authors.lastname: Bergamini
authors.affiliation: Laboratório de Sensores Eletroquímicos (LabSensE), Departamento de Química, Universidade Federal do Paraná (UFPR), CEP 81.531-980 Curitiba-PR, Brazil. Electronic address: luiz1berto@ufpr.br.
authors.forename: Luiz Humberto
authors.initials: LH
authors.lastname: Marcolino-Junior
keywords: Bismuth nanostructures; Ceramic dishes; Electrochemical sensor; Lead