Showing papers by "Ana Maria Oliveira Brett published in 1996"
TL;DR: In this article, an electrochemical method for the determination of the anticancer platinum drug carboplatin using a DNA-modified electrode was developed, and the electrode was successfully used for the electrochemical determination of carbplatin in serum samples of patients with ovarian cancer undergoing treatment.
Abstract: An electrochemical method for the determination of the anticancer platinum drug carboplatin using a DNA-modified electrode was developed. This electrode was successfully used for the electrochemical determination of carboplatin in serum samples of patients with ovarian cancer undergoing treatment. The electrochemical results clearly demonstrated that, for low concentrations, carboplatin interacts preferentially with adenine rather than guanine groups in the DNA and they can contribute to clarifying the mechanisms of interaction of platinum anticancer drugs with DNA. The pharmacokinetics corm ondIng to the administration of the drug was followed electrochemically and the detection limit in serum samples was 5.7 x 10 M. Due to a similar mechanism of reaction with DNA other platinum anticancer drugs can be determined by this method.
87 citations
TL;DR: In this paper, the application of batch injection analysis to the determination of trace metals in samples of volume ≤ 100 μl by square wave anodic stripping voltammetry has been investigated in detail, using a programmable electronic micropipette.
63 citations
TL;DR: Nafion-coated mercury thin film electrodes have been evaluated for use in batch-injection analysis with anodic stripping voltammetry (BIA-ASV) and their effect was found to be much less with the Nafion film coating.
52 citations
TL;DR: It was demonstrated that zinc in zinc-insulin solution can be measured in the presence of dissolved oxygen by square-wave anodic stripping voltammetry (SWASV) at mercury thin-film electrodes on glassy carbon disc minielectrode and cylindrical carbon fibre microelectrode substrates.
Abstract: The electrochemical determination of zinc arising from zinc–insulin complexes was investigated and it was demonstrated that zinc in zinc–insulin solution can be measured in the presence of dissolved oxygen by square-wave anodic stripping voltammetry (SWASV) at mercury thin-film electrodes on glassy carbon disc minielectrode and cylindrical carbon fibre microelectrode substrates. Reoxidation signals arise from complexed zinc at low insulin concentrations (< 100 nmol l–1) and from labile zinc at higher concentrations; the latter can be quantified through linear calibration curves. Batch injection analysis with SWASV was successfully tested for the determination of zinc in zinc–insulin solutions in small sample volumes. Since intracellularly stored insulin exists in the form of a zinc–insulin complex, these techniques are very promising for the indirect study of insulin release from pancreatic β-cells.
25 citations
TL;DR: In this paper, square wave adsorptive stripping voltammetry (AdSV) in conjunction with batch injection analysis technique has been investigated at mercury thin-film electrodes, using analysis of nickel and cobalt ions with nioxime ligand as example, and injection of sample volumes of 5100pL.
Abstract: Square wave adsorptive stripping voltammetry (AdSV) in conjunction with the batch injection analysis technique has been investigated at mercury thin-film electrodes, using analysis of nickel and cobalt ions with nioxime ligand as example, and injection of sample volumes of 5100pL. Experiments were conducted in a HEPES neutral buffered medium, suitable for analysis of biological fluids. Sensitivity is maximized by continuing the adsorptive accumulation after the end of the injection period, and employing the lowest possible injection rate from the electronic micropipette of 24.5pLs-I. The practical detection limit is 5 nM for nickel and 2nM for cobalt. Comparison is made with batch injection analysis with anodic stripping voltammetry and the merits of the technique relative to continuous Row-through methods are assessed.
18 citations