The voltammetric and polarographic behavior of 2-(5-bromo-2-pyridylazo)-5-[N-propyl-N-(3-sulfopropyl)amino] phenol disodium salt dihydrate (5-Br-PAPS) at a hanging mercury drop electrode (HMDE) and static mercury drop electrode (SMDE) has been studied by several techniques including square-wave voltammetry (SWV), differential pulse polarography (DPP), direct current polarography (DCP) and cyclic voltammetry (CV). Current-potential curves recorded at a HMDE and SMDE provide information about the electrode reaction mechanism. The electrochemical reduction mechanism of the azo compound is suggested using SWV, DPP, DCP and CV techniques in different electrolyte media. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.031210jes] All rights reserved.