HPLC analysis of carbohydrates in wines and instant coffees using anion exchange chromatography coupled to pulsed amperometric detection

Carbohydrates (arabinose, fructose, fucose, galactose, glucose, mannose, rhamnose, ribose, sucrose, xylose, and the alditol mannitol) have been analyzed in wines and instant coffees, using anion exchange chromatography coupled to pulsed amperometric detection. Good separation and resolution of the 11 compounds were obtained using just nanopure water as eluent, although rinsing the column with 0.2 M NaOH was necessary to avoid gradual decline in column resolution. Coffee solution, red wines, and rose wines needed a cleanup process by solid-phase extraction on C-18 cartridges. Arabinose, galactose, glucose, xylose, mannose, fructose, and ribose were detected and quantified in red wines using melezitose as internal standard. In the case of the coffee samples mannitol, fucose, arabinose, rhamnose, galactose, glucose, sucrose, mannose, and fructose were quantified and differences between unadulterated and adulterated coffees could be detected.