Manganese has been known as an essential element, whichplays an impor tant role in activation of many enzymes involvedin metabolic processes with respect to man, animals and plants.Trace manganese in biochemical and environmental sampleshave been determined by various methods, including graphitefurnace atomic absor ption spectroscopy, inductive coupledplasma atomic emission spectroscopy or the colorimetric methodbased on formation of formaldoxime complex. However, most ofthese techniques are either not easily amendable to on-site ana-lysis or do not provide suf®cient limits of detection required.Anodic stripping voltammetry (ASV) with a hanging mercurydrop (or mercury ®lm) electrode has proved to be an extremelysensitive electrochemical technique for trace metal analysis [1].However, conventional ASV of manganese suffers from the dif-®culties associated with the relatively low solubility of manga-nese in mercury, large hydrogen evolution background currentand the formation of intermetallic compounds at the mercuryelectrode [2]. Consequently, there is no suf®cient sensitivityachieved. In recent years, traces of manganese have been deter-mined by cathodic stripping voltammetry (CSV) using variety ofsolid electrodes [3±6]. This method involved a preelectrolysisstep whereby the trace Mn(II) was anodically oxidized to Mn(IV)which immediately hydrolyses to form manganese dioxide (or thehydrate) on the electrode surface, then the deposited Mn(IV)oxide was reduced to Mn(II) again. Brainina ®rst reported theapplication of CSV for determination of trace Mn(II) with agraphite and graphite paste electrodes [3]. Roitz et al. success-fully employed CSV for the determination of trace Mn(II) incoast and estuarine waters with glassy carbon electrode [5]. El-Maali and Ei-Hady demonstrated the application of square-waveCSV (SWCSV) at a glassy carbon electrode for selective deter-mination of Mn(II) in some industrial samples. Several nM ofmanganese was detectable by this method [6].