Abstract: In a supporting electrolyte containing NH₃-NH₄Cl, a reduction peak of p-fluoro-(4-diphenylmethylpiperazino-l-yl)-butyrophenone (FDB) was found by linear-sweep voltammetry at Hg electrode.The peak shows a potential of - 1.43 V(vs.Ag/AgCl) and adsorptive characteristics.The peak current was proved to be contributed by the reduction of both surface species of FDBadsorbed at Hg electrode and solution species of FDBdiffusing to the electrode.When the concentration of FDBis sufficiently low, the sweep rate is sufficiently small and the accumulation time is sufficiently long, the peak current is totally contributed by the reduction of adsorbed FDB.The adsorbed species is most probably neutral molecule of FDB.The saturated adsorption amount of FDBat Hg electrode is 7.04 × 10^-11 mol/cm² and every FDBmolecule occupies 2.34 nm².The transfer coefficient a of the irreversible adsorptive system of FDBis 0.64.The detection limit of the adsorptive stripping voltammetry of FDBis 5.0 × 10^-10 mol/Lwhen the accumulation time is 300 s under an optimized condition.

Key words: p-Fluoro-( 4-diphenylmethylpiperazino-1-yl )-butyrophenone, Adsorptive stripping voltammetry, Electrochemical characteristics