The present paper reports a concise study on the mechanism of electrosorption of quercetin (3,3`4`5,7-pentahydroxyflavone) molecule on glassy carbon (GC) electrode surface in 0.1 M sodium acetate-acetic acid buffer, in 90% methanol solution. The recorded anodic charge-transients (obtained by injecting small amounts of quercetin-based buffer to initially quercetin-free buffer solution, carried-out at the constant electrode potential) provided for the first time evidence that the process of mutual interaction between quercetin molecules and the surface of glassy carbon electrode is chemisorptive in its nature. Consequently, a possible mechanism of this adsorbent/adsorbate interaction was proposed. (c) 2010 Elsevier B.V. All rights reserved.