Cathodic adsorptive stripping voltammetry of abscisic acid using pencil-lead bismuth-film electrode

In this study, electrochemical behavior of phytohormone abscisic acid (ABA) at the bismuth-film electrode (BiFE) has been investigated using square-wave cathodic stripping voltammetry. BiFE was prepared ex situ on a supporting pencil-lead graphite electrode. ABA yielded a well-defined voltammetric response in phosphate buffer, pH 3.0 at -1.08 V (vs. Ag/AgCl) (a pre-concentration step being carried out at a fixed potential of -0.80 V for 120 s). The process could be used to determine ABA concentrations in the range 0.756-15.08 mu m, with a detection limit of 0.209 mu m (55.24 ng/ml). As an example, the practical applicability of pencil-lead BiFE was tested with the measurement of ABA in seed samples of maize plant (Zea mays L.).