Electrochemical behaviour of chalcopyrite was investigated in collectorless condition and in the presence of dithiophosphate (DTP), which is a selective collector for chalcopyrite, by cyclic voltammetry (CV) study. Diffuse Reflectance Infrared Fourier Transformation (DRIFT) spectroscopy was employed to identify surface species of DTP at chalcopyrite surface. CV tests established the certain degree of irreversibility in the absence of DTP possibly due to preferential dissolution of iron ions in slightly acid solution, and irreversible surface coverage by iron hydroxides in neutral and alkaline solutions. Cu(DTP)+(DTP)(2) formation as major DTP-compounds on chalcopyrite in slightly acid and neutral conditions was estimated from DRIFT spectroscopy study. However, heavy surface oxidation inhibited the identification of collector species in alkaline condition. (C) 2004 Elsevier B.V. All rights reserved.