Colloidal gold supported onto glassy carbon substrates as an amperometric sensor for carbohydrates in flow injection and liquid chromatography

Abstract

Gold microparticles dispersed on glassy carbon structures were characterized by SEM. Some aspects of the electrooxidation mechanism of carbohydrates in alkaline medium were investigated by cyclic voltammetry. The chemically modified electrode described was tested in flow injection and anion-exchange LC with pulsed amperometric detection. The electrode response was stable: over 8 h a 1.5–3% signal loss was observed for all of the investigated carbohydrates. Typical relative standard deviations ranged between 0.9 and 3.5%. The detector response was linearly dependent on the concentrations of polyhydroxyl compounds and monosaccharides over three orders of magnitude. Linear plots of 1/I_p and 1/c indicated a Langmuir-type adsorption of analyte on the catalytic sites. All investigated carbohydrates were detected at the picomole level. The determination of glucose in human biological fluids was achieved by LC in an alkaline medium.