Topic
Polarography
About: Polarography is a research topic. Over the lifetime, 4772 publications have been published within this topic receiving 75478 citations.
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Abstract: Speciation of model Cu complexes on the basis of size and charge was achieved by anodic stripping voltammetry (ASV) at mercury film electrodes (MFE) coated with Nafion or cellulose acetate Nafion (CANMFE). The Nafion-coated MFE effectively excludes negatively charged Cu complexes, and evidence for the containment of the diffusion layer beneath the Nafion coating is provided. The CANMFE excludes complexes with molecular weights greater than 200, including the Cu-fulvic acid complex, which is of particular interest for speciation in natural waters. Complexation titrations of fulvic acid with Cu show the unsuitability of differential pulse ASV for providing a realistic estimate of the end point (complexation capacity). Differential pulse polarography, which provides results more comparable with bioassays, can be used for the determination of complexation capacity. Results for the speciation analysis of coastal seawater and polluted fresh water are presented. The CANMFE is insufficiently sensitive for seawater analysis, but in polluted fresh water its use indicates that organic and inorganic complexes with molecular weights greater than 200 dominate the speciation for Cd (72%), Pb (96%), and Cu (> 99.8%).
24 citations
TL;DR: The reduction potentials for 1-chloropermethylpolysilanes are in all cases, including the hexasilanes, less negative than those for the corresponding α, ω-dichloropermethyl polysilanes as mentioned in this paper.
24 citations
TL;DR: Current developments in the design and applications of electrochemical-based approaches for the determination of the benzodiazepine class of drugs form their introduction in the early 1960s to 2019 are described.
24 citations
TL;DR: In this paper, two methods for the determination of anti-hypertensive drug Doxazosin by differential pulse polarography and square wave polarography (SWP) based on adsorptive stripping techniques, using a hanging mercury drop electrode are described.
23 citations
TL;DR: In this article, carbon paste electrodes modified with humic acid extracted from a peat area in the Mogi GuaAu River at Sao Paulo State in Brazil showed high reproducibility and particular stability in solution.
Abstract: Polarography at dropping mercury electrode and infrared spectroscopy were used to confirm the reaction of copper(II) ions with humic acid in solution. Polarography allowed observing the reaction to follow the concentration of the Cu(II) in solution while infrared permitted one to follow the humic acid complexation. Cyclic voltammetry experiments, at stationary carbon paste electrode, showed original properties of humic acid which adsorbs at the surface of carbon paste electrode that becomes appropriate for the preconcentration and identification of Cu(II) species. Although very promising the use of adsorption showed the disadvantage of not being reproducible therefore we developed a new preparation method for the carbon paste electrodes modified with humic acid that allow highly repeatable measurements. Humic acid was dissolved in base solution before mixing it with carbon graphite powder and freeze-drying to lead to a fine powder that allows reproducible batches of electrodes. The modification of carbon paste electrode with two different humic acids revealed that the electrochemical behavior of Cu(II) solutions depends on the nature of the humic material. The effects on the electrochemical behavior of Cu(II) of the solutions pH and the ratio of humic acid in the bulk of the electrode were also examined. Such carbon paste electrodes modified with humic acid extracted from a peat area in the Mogi GuaAu River at Sao Paulo State in Brazil showed high reproducibility and particular stability in solution (pH range of 3.0 to 5.5) entitling them to be very good candidates for analytical purposes.
23 citations