Theoretical and experimental study of the catalytic cathodic stripping square-wave voltammetry of chromium species

Cuéllar, Mariela; Vettorelo, Sabrina N.; Ortiz, Patrícia I.; Garay, Fernando

doi:10.1007/s10008-016-3307-3

Cited by 6 publications

(9 citation statements)

References 27 publications

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“…Fig. 5 shows the result obtained after the fitting process, which requires numerous iterative comparisons between experimental and simulated curves [15][16][17][18][19]26]. Once the fitting process was finished, all experimental voltammograms were simulated considering n = 2 and = 0.53, indicating that the electrochemical responses would correspond to the reduction of copper instead of arsenic.…”

Section: J O U R N a L P R E -P R O O Fmentioning

confidence: 99%

“…The cathodic stripping voltammetry (CSV) with Hg as the working electrode is a classical technique for analysis of anions. Although the use of Hg as electrode material is discouraged due to its toxicity, SMDE is still recognized as one of the best electrodes for trace-analysis of various metals as well as for mechanistic studies of those reactions [14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

“…Instead of this, calibration curves with 2 different slopes, the formation of peak-shoulders, and variations of peak-shapes are typical problems found during the electrochemical quantitation of arsenic species [10,21]. Because of this, diverse research groups have found that addition of extremely low amounts of small organic molecules presenting one or more thiol groups enhances the voltammetric response of arsenic [9,10,19]. Those ligands would stabilize the base line, allowing the determination of lower concentrations of arsenic [10,20,21].…”

Section: Introductionmentioning

confidence: 99%

“…and (3) will depend on the concentration of arsenic species, while the chemical equilibria and consequently the slope of calibration curves would be proportional to the amount of both. The presence of a flat profile of I b results not only because of the formation of AsH 3 , but also due to the impossibility of re-oxidizing copper in the absence of arsenide.Suitable simulated curves have to resemble the shape of experimental voltammograms under different scanning conditions[15,16,19,26]. Therefore, the effect of E sw on the shapes of I f and I b is analyzed in Fig 6…”

mentioning

confidence: 99%

“…The counter electrode was a glassy carbon rod and all potentials are referred to a Ag|AgCl|KCl(sat) reference electrode. The parameters of SWV are defined as usual[15][16][17][18][19]22,29].…”

mentioning

confidence: 99%

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Mechanistic analysis of the cathodic stripping square-wave voltammetric response of the copper‑arsenic system at a mercury electrode

Avila

Gómez

Heredia

et al. 2021

Journal of Electroanalytical Chemistry

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Section: J O U R N a L P R E -P R O O Fmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Mechanistic analysis of the cathodic stripping square-wave voltammetric response of the copper‑arsenic system at a mercury electrode

Avila

Gómez

Heredia

et al. 2021

Journal of Electroanalytical Chemistry

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Cathodic stripping square-wave voltammetry for assessing As(III) removal with synthetic mixed oxides

Heredia

Avila

Garay

et al. 2017

J Solid State Electrochem

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Improved voltammetric methodology for chromium redox speciation in estuarine waters

Pađan

Marcinek

Cindrić

et al. 2019

Analytica Chimica Acta

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14Chromium is a toxic element naturally present in natural waters whose chemical speciation 15 regulates its cycling, mobility and bioavailability. We present here: 1-an improved analytical 16 method for chromium speciation (Cr(VI) vs Cr(III)) in estuarine samples by catalytic 17 adsorptive cathodic stripping voltammetric (cat-AdCSV) and 2-a study highlighting a 18 significant change of redox speciation during summer and winter. Initial measurements first 19 revealed that surface-active substances (SAS) present in estuarine samples strongly influenced 20 the analytical determination of Cr by partially masking the Cr peak through an increase of the 21 background current. We found that the application of a low negative accumulation potential (-22 1.65 V) resulted in much better voltammograms compared to those obtained using the usual 23 accumulation potential of -1.0 V . Using humic acid (HA) as a model SAS of natural origin, 24we show that this negative potential clearly prevents adsorption of SAS on the Hg-electrode 25 surface, which in turns benefits the adsorption of the in-situ formed Cr(III)-DTPA complex 26 and the resulting signal. The optimised method was applied to determine chromium redox 27 speciation and distribution along the 23 km long salinity gradient, well oxygenated, Krka 28 River estuary (Croatia). Cr(VI) was found to be the dominant redox species in both summer 29 and winter, with Cr(III) contribution being lower in summer (up to ~30%, average of ~5%) 30 than in winter (up to ~50%, average of ~30%). In summer, lower concentrations of Cr(VI) 31 were found in the freshwater end-member (2.5 nM) than in the seawater end-member (4-5 32 nM), while the opposite trend was found in winter. Hexavalent chromium exhibited a non-33 conservative behaviour along the salinity gradient for both seasons. Chromium predominantly 34 exists in dissolved phase, and contribution of particles reactive Cr(III) was minor. 35

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Theoretical and experimental study of the catalytic cathodic stripping square-wave voltammetry of chromium species

Cited by 6 publications

References 27 publications

Mechanistic analysis of the cathodic stripping square-wave voltammetric response of the copper‑arsenic system at a mercury electrode

Mechanistic analysis of the cathodic stripping square-wave voltammetric response of the copper‑arsenic system at a mercury electrode

Cathodic stripping square-wave voltammetry for assessing As(III) removal with synthetic mixed oxides

Improved voltammetric methodology for chromium redox speciation in estuarine waters

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