The electrochemistry of Cu(II) in aqueous solutions containing triglycine has been investigated at glassy carbon surfaces. Experiments were carried out at the pH range comprising 7 and 10 and a correlation between the electrochemical behaviour and the nature of the Cu(II) species was per-formed. Spectrophotometric and coulometric studies were also done both to characterise Cu(II) and Cu(Ill) species in solution and to prove the existence of a degradation step related to Cu(Ill) complexes. Rotating ring-disc voltammetry was employed to follow this chemical step coupled to the electrode reaction and rate constant values were calculated at three different temperatures. Data show that Cu(Ill)-triglycine species degrades with faster kinetics compared to tetraglycine and pentaglycine Cu(II) complexes. (C) 2004 Elsevier Ltd. All rights reserved.