Determination of nonelectroactive cations by capillary electrophoresis with amperometric detection at a graphite electrode modified with a thin film of mixed-valent ruthenium-iron cyanide

Organic Redox Probes for the Key Oxidation States in Mixed Valence Ruthenium Oxide/Cyanometallate (Ruthenium Prussian Blue Analogue) Catalysts

“…Disturbing of such a complicated systems may result in some secondary structure with predominant RuOx characteristics. The selective determination of Cs in the presence of other alkali metal cations like Li and Na by Fu et al should therefore not be expected at the mvRuOx À FeCN [16]. In their studies the mvRuOx À FeCN was prepared in 0.1 M KCl/HCl of pH 2 bath followed by scanning the electrode in the potential window of À 0.5 to 1.1 V (vs. Ag/AgCl) in 0.1 M KCl (pH 5) until a steady profile was obtained.…”

“…There is even inconsistency in the reported electrochemical behavior of the mvRuOx À MCN films. For example, Cataldi et al reported three redox peaks in the potential region from À 0.2 to 1.2 V (vs. Ag/AgCl) for mvRuOx À FeCN [14]; whereas, Fu et al observed only two redox peaks in the same potential range [16]. Gorski and Cox reported oxy/hydroxy-Ru IV/III and Ru VI/IV redox transitions for mvRuOx À RuCN at 0.8 and 1.0 V (vs. Ag/ AgCl), respectively, in pH 2 solution [13].…”

“…The redox assignment, however, is different from that of classical solid state and solution phase oxy/hydroxy-ruthenium chemistry, where the Ru IV/III and Ru VI/IV redox transitions should occur in the potential range from 0.06 to 0.14 V and 0.56 to 0.81 V (vs. Ag/AgCl), respectively, in pH 2 solution [18 ± 24]. Recently, Fu et al selectivity determined Cs ion by using mvRuOx À FeCN [16], which is against the property of size insensitive to alkali metals for the classical PB analogues [2,14]. There are obvious qualitative changes in the redox and electrochemical features of the catalysts from time to time.…”

Analysis of inorganic and small organic ions by CE with amperometric detection

“…Carbon electrodes are most widely used in CE-AD systems for analysis of inorganic and small organic ions. The forms of carbon electrodes include carbon fiber [16,54,58,59,61,67,68,[72][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90], glassy carbon [17,91], graphite [92], carbon paste [93][94][95][96], carbon film [56,63,65,66,70,71,[97][98][99][100][101][102][103][104], etc. Advantages of carbon electrodes include wide useful potential range, low overpotential and background noise, rich-surface chemistry, minimal fouling, available in a variety of forms and low cost.…”

Detecção eletroquímica em eletroforese capilar

“…Wang e colaboradores têm utilizado deposição de partí-culas de platina 54 e paládio 60,61 sobre fibra de carbono. Eletrodos modificados com rutênio de valência mista têm sido aplicados na determinação de compostos com grupos sulfeto 69,213 e espécies não-eletroativas 214 . Vários compostos podem ser determinados em eletrodos modificados com ftalocianinas de cobalto 69,74,215,216 .…”