Determination of arsenic by anodic stripping voltammetry and differential pulse anodic stripping voltammetry

Abstract

Figure 3. Correspondence of results obtained with the column RIA procedure and the dextran-coated charcoal method patients on digitoxin therapy is immunologically indistinguishable from the digitoxin in the standards. In other words, the antibody recognizes the digitoxin in clinical specimens and standards as identical. As shown in Table II, acceptable results were obtained in a parallelism study over a sixfold range of dilution. These data indicate that various components in the serum, including potentially cross reacting materials, do not interfere in the test.

Electrocatalysis of the anodic oxidation of As(III) on platinum and other noble-metal electrodes

“…This same conclusion was reached by Forsberg^^. (21), who performed differential pulse ASV as well. These workers found Hg and Ag to be completely unsatisfactory as electrodes.…”

“…The stripping peak at 0,2 V is therefore due to the stripping of As in the outer As layers ( , As stripped from an As substrate), while the peak at 0.5 Vis due to the stripping of the As in the first 1-2 monolayers. The observation of one and two stripping peaks has been reported in the determination of arsenic by anodic stripping voltammetry (19,21).…”

“…Finally, Forsberg e^£l_. (21) saw an enhancement in the stripping peak area on a Pt electrode when a Au(III) salt was added to the electrolyte. This could be due to either a partial As deposition on a deposited Au surface, thereby enhancing the reversibility, or to an increase in the real surface area which would lead to a less-hindered deposition.…”

“…These authors recognized that oxide films on the electrodes presented difficulties, so a pretreatment step was included in the experimental procedure to ensure that deposition occurred on a reproducible, reduced surface. A negative deviation in the calibration curve of high [As(III)] was attributed to "the formation of a monolayer of adsorbed As, a poor electrical conductor, at the electrode surface" (21). Finally, Forsberg e^£l_.…”

Determination of As(III) by anodic stripping voltammetry using a lateral gold electrode: Experimental conditions, electron transfer and monitoring of electrode surface

“…In particular, gold was found to be the superior substrate as a working electrode for arsenic determination [20,29,30], because it provides a more sensitive response toward arsenic oxidation than other electrode materials and has a higher hydrogen overvoltage than platinum [31,32]. Problems occurring with solid electrodes include the dependence of their response on pre-treatment and the formation of oxide films, which limits sensitivity and reproducibility and, as a consequence, their use for routine applications [23,33].…”