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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TL;DR: In this paper, the approximate l = i ( l ) curves proposed in Part I are compared with the exact ones, and their accuracy with respect to the values of the adsorption parameters and the pulse amplitude is discussed.
20 citations
TL;DR: Some adsorption isotherms for anion-induced adaption of metal ions are proposed in this paper, and the influences of adsorbing on d.c polarograms are examined theoretically.
20 citations
TL;DR: The polarographic method has been applied to determine thymoquinone in two black seed oil preparations available on the Austrian pharmaceutical market and showed a distinct peak in Sörensen buffer:methanol.
Abstract: A reliable and simple differential pulse polarographic method is described for the determination of thymoquinone in black seed oil. The polarographic behaviour of thymoquinone was examined in various buffer systems over the pH range 5.0-10.0. Thymoquinone is reduced in a single, reversible peak at the dropping mercury electrode. The differential pulse polarogram showed a distinct peak in Sorensen buffer:methanol (3:7, v/v; pH 8.5) at a peak potential of -0.095 V (vs. silver/silver chloride electrode), and a plot of peak height against concentration was found to be linear over the range 0.2-15.0 microg/mL (R = 0.9998). The limit of detection was calculated to be 0.054 microg/mL. The polarographic method has been applied to determine thymoquinone in two black seed oil preparations available on the Austrian pharmaceutical market.
20 citations
TL;DR: In this article, the authors derived theoretical expressions for pseudopolarography at a hemispherical mercury ultramicroelectrode and compared with experimental data at varying deposition times and low and high electrolyte concentrations and with previous theory for other electrodes.
Abstract: Trace heavy metals play a central role in many biogeochemical processes. Their toxicity and bioavailability in aqueous systems has been shown to be directly related to the chemical forms in which they exist, i.e., their chemical speciation. Especially promising in speciation studies has been an electrochemical technique referred to as pseudopolarography or stripping polarography. The theoretical expressions for pseudopolarography at a hemispherical mercury ultramicroelectrode are derived and compared with experimental data at varying deposition times and low and high electrolyte concentrations and with previous theory for other electrodes. It is shown that, even though several of the physical conditions are different, the behavior of both the pseudopolarographic half-wave potential and the limiting peak stripping current is similar to that for the HMDE. The fit between the theory and the experimental data was excellent. A correction term for the increase in the limiting peak stripping current with increasing negative deposition potentials seen in this and previous works is discussed and attributed to adsorption of trace organics on the mercury electrode surface. 21 refs., 4 figs., 1 tab.
20 citations
20 citations