The electrochemical behaviour of acidic and neutral pharmaceutical active compounds (PhACs) was studied by cyclic voltammetry and pulse voltammetric techniques on mercury, carbon nanotube paste, carbon paste and gold electrodes. The best results, in terms of sensitivity, linearity range and detection limits, were obtained by differential pulse voltammetry (DPV) for ofloxacin (LOD 5.2 mu M), differential pulse polarography (DPP) for clofibric acid (LOD 4.7 mu M) and normal pulse voltammetry (NPV) for diclofenac (LOD 0.8 mu M) and propranolol (LOD 0.5 mu M). An enrichment step of approximately two orders of magnitude was performed by a solid-phase extraction procedure (SPE) in order to concentrate the samples. The developed method was optimized and tested on spiked river water samples. (c) 2005 Elsevier B.V. All rights reserved.