Determination of Carbohydrates by Capillary Zone Electrophoresis with Amperometric Detection at a Copper Microelectrode

Caplllary zone electrophoresis (CZE) was employed to separate sugars accordlng to their electrophoretic moMlitks In strong alkallne clolutlons (pH ca. 13). Saccharide zones were monltored electrochemlcaliy udng amperometrlc detectlon at a constant potentlal, 0.6 V (vs Ag/AgCI), with a cyllndrlcal copper wire electrode (25 pm In diameter). The Cu-wire microelectrode In strong badc solutions had electrochemlcal behavlor slmllar to that of Cu electrodes with larger dlmendono and appeared to &ow no deterloratton for hundreds of runs. A sample mixture contalnlng 15 different sugars was separated In l e r than 45 mln with reparation efflclencles up to 200 000 theoretical plates. The callbratlon plot was found to be llnear over 3 orders of magnitude and the llmits of detection for the saccharides studied were In the femtomole range.