DETERMINATION OF SUGARS BY LIQUID-CHROMATOGRAPHY AND AMPEROMETRIC DETECTION WITH A CUPROUS-OXIDE MODIFIED ELECTRODE

A chemically modified electrode was applied as a working electrode for the amperometric detection of sugars in liquid chromatography. A mixture of cuprous oxide and conductive carbon cement was used as electrode material. Cuprous oxide acted as a catalyst for the oxidation of sugars. Cyclic voltammetry was used to examine the oxidation of the sugars at the electrode surface. The stability and sensitivity of a cuprous oxide/conductive carbon cement (20/80 %, w/w) electrode were tested in flow injection analysis experiments. For liquid chromatography, sugars were separated on an ion-exclusion column with 0.01 M H2SO4 as mobile phase. After the separation, 0.2 M NaOH was added post-column and the sugars were determined at 550 mV vs. Ag/AgCl. Calibration was linear in the range of 10(-6). 10(-3) M with limits of detection of approximately 1 . 10(-6) M. The application of the modified electrode for the determination of sugars in fruit beverages and dairy products following chromatographic separation is shown.