A cobalt-based glassy carbon (Co/GC) chemically modified electrode (CME) is described for use as an amperometric detector in the flow analysis of mono-, di- and trisaccharides. The preparation of the electrode is very easy and rapid. As with copper- and nickel-based glassy carbon electrodes, the Co/GC CME allows the electrocatalytic oxidation of scarcely electroactive compounds without recourser to pulsed waveform potentials. Hence, constant-potential amperometric detection is feasible and it has been applied successfully to reducing and non-reducting sugars. The chemical nature of cobalt species on glassy carbon was investigated using x-ray photoelectron spectroscopy and the results indicate that a Co(III) oxide hydroxide is present on the glassy carbon surface. However, electrochemical detection in an alkaline mobile phase of aliphatic organic compounds seems to take place through mediation of Co(IV) species produced from the oxidation of Co(III) during anodic polarization. Carbohydrates and related polyhydroxy compounds were determined at the micromolar level with an operating potential of 0.50 V vs. Ag/AgCl after anion-exchange chromatographic separation. The detector responds linearly to an increase in glucose concentration with a linear dynamic range that extends over three orders of magnitude (0.5 μM-0.5 mM).
|Titolo:||Cobalt-based glassy carbon chemically modified electrode for constant-potential amperometric detection of carbohydrates in flow-injection analysis and liquid chromatography|
DESIMONI, ELIO (Penultimo)
|Parole Chiave:||Amperometry; Carbohydrates; Chemically modified electrodes; Cobalt-based electrodes; Flow injection; Liquid chromatography|
|Settore Scientifico Disciplinare:||Settore CHIM/01 - Chimica Analitica|
|Data di pubblicazione:||1992|
|Digital Object Identifier (DOI):||10.1016/0003-2670(92)80103-E|
|Appare nelle tipologie:||01 - Articolo su periodico|