The electrochemical oxidation of benzoquinone on expanded graphite (EG) electrode was conducted. Electrochemical process was realized by cyclic voltammetry technique in alkaline solution. The main part of this work was devoted to examination of benzoquinone oxidation proceeding through the opening of aromatic ring accompanied by the formation of carboxylic acids. Water samples containing benzoquinone and short chain mono- and dicarboxylic acids were analyzed qualitatively and quantitatively with high performance liquid chromatography (HPLC). The validation of chromatographic method was determined for benzoquinone, oxalic acid, malonic acid, acetic acid, maleic acid, succinic acid and fumaric acid. (C) 2012 Elsevier Ltd. All rights reserved.