The electrochemical oxidation of iodic acid and lithium iodate to periodate, a powerful oxidation agent for dialdehyde carbohydrates, was investigated for various anode materials (viz. boron-doped diamond, lead and platinum). Galvanostatic electrolyses and voltammetric experiments were carried out for iodic acid, iodic acid-lithium iodate and lithium iodate-lithium hydroxide solutions. It was found that the maximum periodate current efficiency for boron-doped diamond and lead electrodes is about 0.6 and for platinum electrodes almost zero. A reaction mechanism for the oxygen and periodate formation on the boron-doped diamond electrode in acid solution has been proposed. For a boron-doped diamond electrode in the high potential range the charge transfer coefficient and the exchange current density for the oxygen evolution are 0.14 x 10(-4) and 4 x 10(-4) A m(-2), respectively. (C) 2003 Elsevier Ltd. All rights reserved.