PRECONCENTRATION AT A CARBON-PASTE ELECTRODE AND DETERMINATION BY ADSORPTIVE-STRIPPING VOLTAMMETRY OF RUTIN AND OTHER FLAVONOIDS

The non-Faradaic preconcentration behaviour of nine flavonoids (six fl avones: fisetin, galangin, morin, quercetin, rhamnetin, rutin, and thr ee flavanones: hesperidin, hesperitin, naringin) at a carbon-paste (nu jol/graphite) electrode and the factors affecting it (pH, accumulation potential, presence of various surfactants) for their subsequent diff erential pulse voltammetric determination are examined. All flavones t ested are readily accumulated on the carbon paste electrode resulting in a considerable signal enhancement making determinations feasible do wn to 10(-8)-10(-7) M after preconcentration for 1-4 min. Flavanones a re not preconcentrated so their lower determination limits are of the order of 10(-6) M. A simple voltammetric procedure for the determinati on of rutin in a multivitamin preparation is presented.