Determination of dihydrozeatin and dihydrozeatin riboside by cathodic stripping voltammetry

The present study develops methods to quantify the phytohormones dihydrozea tin (DHZ) and dihydrozeatin ridoside (DHZR) using cathodic stripping and di fferential pulse voltammetry (DPS). Employing a supportive electrolyte with 0.04 M acetic/acetate buffer pH 4.5 and 40 s accumulation time at -0.60 V, the detection and determination limits for DHZ were 5.5 and 8.0 ng mL(-1), respectively. For DHZR using a 0.04 M acetic/acetate buffer pH 4 with a 50 s accumulation time at -0.95 V the detection limit was 16.0 ng mL(-1) with a determination limit of 24.0 ng mL(-1). Both methods were successfully ap plied to determine minute amounts of cytokinins in apples.