Polarographic Study of the Iodine-Iodide Couple at the Rotating Platinum Electrode.

“…It is known, indeed, that iodide oxidation occurs via many steps in which adsorption-desorption process are involved; this was studied in detail for Pt electrodes [27][28][29][30] and for gold electrodes as well [31][32][33][34]. For the latter case, it was shown by Weaver and coworkers [34] that iodide electroxidation follows the pathway (where "ads" refers to an adsorbed species):…”

Section: Cyclic Voltammetry Of Iodidementioning

confidence: 99%

“…in the environment or in foodstuff, directs methods (which could avoid a preconcentration step) might be preferable. It was shown that at low pH values, the electrochemical oxidation of dilute solutions of iodide at Pt [27][28][29][30] or Au [31,32] electrodes is reversible, however, at iodide concentrations equal or higher than 1 mM the process is complicated by the formation of adsorbed iodine films. The structure of the adsorbate layer was studied by surface-enhanced Raman spectroscopy on gold electrodes by Weaver and coworkers [33,34].…”

Section: Introductionmentioning

confidence: 99%

Gold nanoelectrode ensembles for direct trace electroanalysis of iodide

Pereira

Moretto

Leo

et al. 2006

Analytica Chimica Acta

View full text Add to dashboard Cite

A procedure for the standardization of ensembles of gold nanodisk electrodes (NEE) of 30 nm diameter is presented, which is based on the analytical comparison between experimental cyclic voltammograms (CV) obtained at the NEEs in diluted solutions of redox probes and CV patterns obtained by digital simulation. Possible origins of defects sometimes found in NEEs are discussed. Selected NEEs are then employed for the study of the electrochemical oxidation of iodide in acidic solutions. CV patterns display typical quasi-reversible behavior which involves associated chemical reactions between adsorbed and solution species. The main CV characteristics at the NEE compare with those observed at millimeter sized gold disk electrodes (Au-macro), apart a slight shift in E 1/2 values and slightly higher peak to peak separation at the NEE. The detection limit (DL) at NEEs is 0.3 M, which is more than one order of magnitude lower than DL at the Au-macro (4 M). The mechanism of the electrochemical oxidation of iodide at NEEs is discussed. Finally, NEEs are applied to the direct determination of iodide at micromolar concentration levels in real samples, namely in some ophthalmic drugs and iodized table salt.

show abstract

“…45 Additionally, the redox reaction and related chemistry of I − /I 3 − are also well-known. [46][47][48][49] According to the previous reports, [50][51][52][53] the characteristic absorption maxima of I 3 − in aqueous solution appear at 286 and 353 nm. Although the former band is hidden in the strong absorption by DMF solvent, that corresponding to the latter can be observed at 365 nm in Fig.…”

Section: Iodidementioning

confidence: 96%

Uranyl–halide complexation in N,N-dimethylformamide: halide coordination trend manifests hardness of [UO2]2+

et al. 2013

View full text Add to dashboard Cite

Complexation of [UO2](2+) with Cl(-), Br(-), and I(-) in N,N-dimethylformamide (DMF) was studied by UV-vis absorption spectroscopy and extended X-ray absorption fine structure (EXAFS) to clearly differentiate halide coordination strengths to [UO2](2+). In the Cl(-) system, it was clarified that the Cl(-) coordination to [UO2](2+) in DMF proceeds almost quantitatively. The coordination number of Cl(-) almost quantitatively increases up to 4, i.e., the limiting complex is [UO2Cl4](2-). Logarithmic gross stability constants of [UO2Cl(x)](2-x) (x = 1-4) were evaluated as log β1 = 9.67, log β2 = 15.49, log β3 = 19.89, and log β4 = 24.63 from UV-vis titration experiments. The EXAFS results well demonstrated not only the Cl(-) coordination, but also the DMF solvation in the equatorial plane of [UO2](2+). The interaction of Br(-) and I(-) with [UO2](2+) in DMF was also investigated. As a result, the Br(-) coordination to [UO2](2+) stops at the second step, i.e., only [UO2Br](+) and UO2Br2 were observed. The molecular structure of each occurring species was confirmed by EXAFS. The evaluated log βx values of [UO2Br(x)](2-x) (x = 1, 2) are 3.45 and 5.42, respectively. The much smaller log βx than those of [UO2Cl(x)](2-x) indicates that Br(-) is a much weaker ligand to [UO2](2+) than Cl(-). The EXAFS experiments revealed that the presence of I(-) in the test solution does not modify any coordination structure around [UO2](2+). Thus, I(-) does not form any stable [UO2](2+) complexes in DMF. Consequently, the stability of the halido complexes of [UO2](2+) in DMF is exactly in line with the hardness order of halides.

show abstract

Polarographic Study of the Iodine-Iodide Couple at the Rotating Platinum Electrode.

Cited by 33 publications

References 13 publications

Voltammetry of iodine(I) chloride, iodine, and iodate at rotated platinum disk and ring-disk electrodes

Voltammetry of iodine(I) chloride, iodine, and iodate at rotated platinum disk and ring-disk electrodes

Gold nanoelectrode ensembles for direct trace electroanalysis of iodide

Uranyl–halide complexation in N,N-dimethylformamide: halide coordination trend manifests hardness of [UO2]2+

Contact Info

Product

Resources

About