Electrocatalysis and detection of carbohydrates by anion-exchange chromatography at a gold substrate electrode modified with nickel cyanide ions

Chemically modified electrodes obtained by direct interaction between gold substrate and tetracyanonickelate(II) ions in alkaline medium were characte rized by cyclic voltammetry toward the electrooxidation of carbohydrates. S atisfactory performance with respect to catalytic stability, background cur rent stability and lowering of detection limit was obtained for the analysi s of ten oligosaccharides contained in a synthetic sample by anion-exchange chromatography in alkaline solutions. Under constant applied potential of 0.55V (vs. Ag/AgCl), the detection limits (S/N=3) for all investigated comp ounds ranged between 3 and 6 pmol injected for melezitose and turanose, res pectively. The dynamic linear ranges spanned generally three orders of magn itude above the limit of detection. The effects of the concentration of tet racyanonickelate(II) ion on the catalytic activity, amperometric stability and chromatographic separations were examined.