Chapter 25 Pulsed electrochemical detection of carbohydrates at noble metal electrodes following liquid chromatographic and electrophoretic separation

Abstract

Publisher Summary This chapter discusses the pulsed electrochemical detection (PED) of carbohydrates at noble metal electrodes following liquid chromatographic and electrophoretic separation. PED technology is developed to achieve the highly sensitive and reproducible detection of alditols, monosaccharides, and oligosaccharides at Au electrodes. Aldehyde and terminal alcohol moieties in carbohydrates can be detected with high sensitivity by oxidation at Au electrodes in alkaline media and at Pt electrodes under all pH conditions. The anodic response of these compounds is electrocatalytic in nature with the direct participation of the electrode surface within oxidation mechanisms. While all carbohydrates yield a PED response, only aldoses (reducing sugars) can be detected selectively because of the judicious choice of the detection potential within PED waveforms. The analytical impact of HPLC–PED can be appreciated on the basis of the recognition that (1) carbohydrates are polar compounds and therefore are not easily separated by gas chromatography (GC) and (2) these compounds are aliphatic without conjugated bonding and therefore are not easily detected by conventional photometric or fluorometric techniques without a priori derivatizations to attach chromophoric functional groups.